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routercnc
09-01-2014, 08:14 PM
Quick overview of cnc machine mk3 which is nearing completion. Main uses are still balsa, liteply, and wood routing, but I've also been doing more aluminium recently.

Only the Z axis and gantry top from the Y axis have been retained, everything else is new.

Bed
Bed is now 80x80 aluminium profile (heavy gauge) with multiple cross members. One more is due to be added in addition to those shown in the photos, plus further crossbracing in other directions. Intention is to be able to bolt a big machine vice directly to the bed for ali work, and/or purchase a milling table (e.g SIEG 400x125 T-slot) for bigger bits. For wood cutting the bed would instead support an 18mm ply main board followed by a sacrificial board.

Gantry
The sides are 100x50x6 RHS with sliced profile inserts to allow bolting through without crushing. At the base of the gantry is a 30mm thick block drilled lengthways to take the 16mm ballscrews, bolted down onto the bearing blocks, and bolted from the sides to take M12 bolts from the side sections.
There is an adapter plate to join the ballscrew to the front of these blocks. It was quite a squeeze to get all these bits to together without clashing but I'm glad I persisted with the design to get a good joint.
Gantry drive is now twin X axis not single.
The gantry itself now runs on supported rail rather than a cobbled together set of roller bearings. I considered profile rail but at these lengths it gets expensive.

Y axis
This uses the parts from mk2 as they worked well. I've designed the layout to allow me to move the stepper motor to the side and drive the ballscrew via a belt in future. This is mainly for neatness.

Dust extraction
I've posted the details in a recent post but this will be an automatic floating shoe using 100mm clear flex pipe throughout.

Spindle
Spindle is the existing 1.5kW water cooled unit and 1.5kW Moeller VFD drive. If I were to start again I would go for the 2.2kW spindle as it can take the ER20 collect (up to ~12mm). I stalled the 1.5kW spindle quite often if I slowed the speed enough for drilling so more power would be better and I don't think any extra weight would bother the rest of the machine.

Enjoy the pics . . .
11229112301123111232
11233
1123411235

For info the old mk1 and mk2 machines can be found here:
http://www.mycncuk.com/forums/gantry-router-build-logs/1923-time-mk2-upgrade.html

GEOFFREY
09-01-2014, 08:52 PM
Looks neat and purposeful. Very nice. G.

Lee Roberts
09-01-2014, 09:10 PM
Looks nice !

routercnc
26-01-2014, 12:17 PM
Few more photos to show progress . . . .

General machine is starting to come together. Gantry now fixed squarely onto rails, Y axis and Z axis all wired up and running. Both run beautifully smooth but then they were carried over from the old machine without disturbing them.
11374

Extractor hose upgrade to 100mm. Will use the m/c to make bits for the extractor brackets etc.
11375

Y axis stepper currently mounted on the end of the ballscrew for now. For neatness, and give a bit more space for possible future acoustic enclosure, the layout of the drag chains behind the gantry have space reserved to move the stepper behind the gantry for a belt driven Y axis.
11376

Have just finished wiring new slave driver, and configuration for twin stepper drive. It all works but needs a bit of fettling to get everything aligned.

The X1, Y, Z axes all run from the system3 board, and the slave X2 runs from the A axis output via an M542 stand-alone driver. This is fine except I had to de-tune the X2 axis (M542) as it was more capable then the X1 axis and I clearly don't want an asymetric gantry stall during running (!).

As per a previous post I intend to upgrade all the control system as per Jazz and Jonathan's suggestions to 60V PSU and 80V drivers (DQ860MA are top of the list). Didn't need much pursuading to be honest, especially having now compared the performance of X1 vs X2. I'm still on 26v so expect great things from 60v when I get there!

The bed of the machine will have more crossmembers than currently shown, plus short connecting pieces between the crossmembers in the X direction.

Cooling system on Z axis was a temporary solution several years ago on the previous machine - I intend to re-locate the radiator out of the way, although there is a good chance it will just stay there again !

Still need to wire up the home switches, which were taken off the old machine I but need additional bits for gantry squaring which the old machine didn't need.

The wooden end bearing supports on the end of the bed are temporary - machine will be used to make ali ones. Used like this I suspect the gantry could be driven hard against the wood and break them off, which would be pretty bad! Esp. on 60V.

routercnc
11-02-2014, 08:40 PM
Brief update.

I've been working on the bed making up brackets and crossmembers. The previous bed was a piece of 18mm ply with very little support. I intend to make this one much better and with the move from single central ballscrew to twin X drive I can now use all the space in the middle.

My chopsaw (with TCT blade) made short work of the aluminium angle brackets (1.25"x1.25"x1/4"), and then on to using the machine for the first time to cut all the holes out.
11570

I had to rig up a quick bed support for the vice to machine the holes.
11571

Putting it together.
11573

The bed assembled . . .
11572
This is a multi-function bed with vice work at one end, flat work in the middle, and limited 'end-on' work at the far end. Or everything can be stripped and a wooden sacrifical bed added.

Running a DTI over the bed (in spindle) shows there is some uneven-ness which was confirmed with a flat edge so I plan to lightly skim it. This will only be as level as the rails allow but will be better than the current condition.

I've taken some machine stiffness measurements but I'll put those in another post later to keep this one for the build.

Thanks for the all positive comments - keeps me going !

routercnc
04-04-2014, 10:38 PM
One of the ballscrews that I sent away to be straightened was returned some time ago but I've not had much time recently to put it back together (started a post on that subject and will update at some point!). So last weekend I had another session on the machine and took the opportunity whilst refitting the ballscrew to shim both X axis AC bearings and pack in some grease. I also corrected one of the AC bearing pairs which were not face-to-face, but line-astern.

Before the shims were fitted I could grab the ballscrew and move it back and forth ever so slightly, possibly 0.1mm or so, but now it is nice and solid.

I also noticed that the cap head bolts holding the X axis stepper motors on were hard against the laminations of the motor body, preventing the bolts sitting centrally in the mounting hole. This was preventing me from inserting all 4 bolts fully, and putting a twist/offset in the coupling, so I end up drilling out the thread in the mounting bracket to a large clearance hole and using a nut and bolt to secure the motor. The Y axis motor is a different model (but similar spec) and seems to have more clearance for the cap heads and went on without a problem.

After all this work the X axis is now running much more smoothly - a bit more adjustment should have it just right.

With everything looking good I decided to lightly skim the bed frame - see photos below. As my spindle is a 1.5kW model with a maximum collet size of around 6mm it took some time but it's done now.
12000

12001

12005

I've also managed to re-mount the cooling system off the side of the gantry rather than on the Z axis. This was mainly for cosmetic reasons but whilst doing this I had difficulty filling the system and eventually realised that the spindle was blocked. A quick blast of compressed air and all was well. It must have been running like this for some time but I didn't notice the spindle getting warm so I'm clearly not stressing the machine for the little jobs I throw at it. I was going to buy one of those computer water cooling flow indicators (small vaned disc which rotates with the water flow) but noticed that a thin strand of the PTFE tape on the outlet of the spindle connection fluttered about when the pump was started so decided to just look at that instead!

I don't have a detailed photo story of the cooling system relocation but you can see the initial Vs the almost finished layout in these 2 photos:
12003
vs
12004

Now I'm working on replacing the last 2 wooden parts on the machine (Y axis ballnut mounting plate and the Z axis stepper motor plate). The first one should improve Y axis stiffness, and the second one will just make it look nicer.

The other improvement parts in the pipeline are:
Much better Z plate with pockets for the Z ballscrew etc.
Buying one of those SMA50 GUU linear bearings (from Zapp) to convert to an 80mm spindle mount
Long awaited upgrade of the control system to seperate drivers on 60V (from an all-in-one at 27V)

I hope I can stop myself from further upgrades at that point since the machine already cuts through wood, liteply, and balsa with more speed and accuracy than I could ever need. And yet I find myself sketching mk 4 . . . . worrying.

EddyCurrent
04-04-2014, 11:25 PM
I also corrected one of the AC bearing pairs which were not face-to-face, but line-astern.

Are you sure you don't mean back-to-back ? see here http://www.mycncuk.com/forums/gantry-router-build-logs/6565-ready-steady-eddy-21.html#post56132

Those bearings really do need attention, all the ones I bought had to have the bearings turned, shimmed, and greased.

The cooling system looks far better on the side of the gantry and I like the sound of the cheapo flow indicator.

routercnc
05-04-2014, 05:57 PM
Hi Eddy,

Thanks for the link -I'd missed some of that thread first time around.

I positioned them with the side engraved '7001 AC' touching each other. That face has the outer race 'peened' over as per SKF-fig2 in the link above. If that is the 'back' then yes they are back-to-back.

routercnc
07-04-2014, 11:21 PM
Finally decided to place an order yesterday for 3off DQ860MA drivers and a 60V 10A supply (Z will use existing MD542). This is from Wantai motors and includes a BoB. I'm going to use this BoB initially and see how it goes. Whilst I'm waiting for those nice new bits to arrive, I'm thinking about upgrading the home/limit system to reduce the false e-stops which very occasionally occur. All limits & homes wire straight into the system3 board currently.

Reading around suggests:
home - proximity switches DIRECT to BoB input (for speed and accuracy)
limit - 24V system though relay then to BoB input (for reducing false e-stops and noise etc)

My question is about the 24V system. I've found a 24V 4-channel relay module board. I intend to use this for limits, probe, and two spare. Questions are:
1. It comes in 'active high' or 'active low' versions. Which one do I need? I'm guessing active low since the 24V would run through the NC switches and into the board so would be 'high' during normal running. When the switch opened the 24V circuit would be broken and go 'low'?

2. In terms of wiring this board looks like it needs 24V DC input, then the switches wire straight into the relay board without any other bits required, and the output contacts wire straight into the BoB without other bits- is this correct?

3. Is this board suitable for this or is there something better?


4-Relay Module with Optocoupler isolation High & Low Level Trigger 5v 9v 12v 24v | eBay (http://www.ebay.co.uk/itm/4-Relay-Module-with-Optocoupler-isolation-High-Low-Level-Trigger-5v-9v-12v-24v/151248613838?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222003%26algo%3DSIC.FIT%26ao%3D1%2 6asc%3D20891%26meid%3D6043548699394165663%26pid%3D 100005%26prg%3D9312%26rk%3D2%26rkt%3D6%26sd%3D1212 40524419&rt=nc#ht_2740wt_952)


Thanks

irving2008
08-04-2014, 07:59 AM
I'd like to see a wiring diagram for the board, there's no mention of current limiting resistors, so assume it has some. My guess though is thst active low means pulling the input to ground for current to flow through the opto's diode which is connected to the supply rail and active high means the diode is grounded and a voltage is applied to activate it..

Assuming active low, a 2-wire switch is wired from input to ground, + side to input. An NC switch is always preferred so the relay is always energized and loss of supply or wire break is a fault.

A 3-wire NPN NC switch would be wired to +24v and ground, output to the input.

Similarly on the BOB input, the relay NO connection (as this is closed coz the relay is energized) is used as input to the BOB so again a break in the wiring or relay board is a fault condition.

Whether you need any other bits depends on whether pullup and/or current limiting resistors are in place.

Personally if you have open-ended optoisolated inputs on the BOB (i.e. access to both ends of the diode) the use of an intermediate relay board reduces reliability and adds complexity and cost for no real benefit.

JAZZCNC
08-04-2014, 11:42 AM
Don't use a relay for the probe as you'll get a delay and you don't want that.

Regards the relay then just use a Standard 12 or 24V relay for the limits. Unless your BOB inputs can accept 24V which they won't All your doing is running the 5V signal from BOB thru the NO contacts and keeping the wire length to the shortest possible. Most false trips are picked up from the Long limit switch wire runs connected directly to the input and often close to power cables acting as antena picking up stray signals. Using 24V means you can run it thru the Limits and E-stop to power the Relay coil making the system stable and won't trip the relay unless broken and keep the Signal wires short and inside the Control box.

Also I wouldn't use Solid state Relays as they tend to fail On which is BAD news for limits.!!

EddyCurrent
08-04-2014, 01:24 PM
This is a similar 5v version, SainSmart 4-Channel 5V Relay Module for PIC ARM AVR DSP Arduino MSP430 TTL Logic Specializing in Arduino compatible development boards and modules, oscilloscopes and other electronics. (http://www.sainsmart.com/arduino/arduino-components/relays/4-channel-5v-relay-module-for-pic-arm-avr-dsp-arduino-msp430-ttl-logic.html)

Circuit drawing 12012

As Irving said regarding active low etc., as Dean said regarding probe and 24v circuit.

I'm a big fan of 'volt free' contacts, i.e. in this case the contacts of the relays, it lets you interface different voltages from different sources without problem and if you want to add other things into the circuit later on you won't have to modify existing parts to accommodate it. As Irving says, fewer components is more reliable but in this instance my preference is to use a relay.
In my case I eventually used 3 wire proximity switches for the home switches directly into the bob and a PILZ relay with the limits in series with E/Stop switches and then one of the PILZ relay contacts into the bob.

routercnc
08-04-2014, 01:31 PM
Irving,
Thanks for the info. Yes, by 'other bits' I was referring to additional resistors to limit the current. It's not clear from the description but as this appears to be a module I think they must already be there. Thank you for the general explanation, that clears up the areas I was thinking about.
As for adding complexity etc. my main reason for looking into this was to reduce or eliminate false e-stops on the limit circuit. The homes and probe would be direct to the BoB as before. It is only the limits I was considering going to 24v via a relay. I think that is where the benefit will be - but when the new driver and BoB system has arrived I'll try it all direct to the BoB and see what happens.

Jazz, thankyou that confirms how I thought this would all operate. And yes, good point about no probe on a relay.
The reason I looked at a module system mounted to a board was to have simple wire connections. I had looked at automotive relays as these use standard spade terminals and had a mounting bracket, but then wondered about current resistors and diode spike protection and whether this was inside the relay box or not. Basically I don't want to have to build a PCB circuit board for this, just spade or terminal blocks onto something which works. So would the automotive type be OK?
I also looked at solid state relays but will avoid on that advice. I quite like hearing a click anyway to confirm all is well.

Eddy,
Thank you, I did look at that as well but it talked about PIC and Arduino and I didn't know what to make of it. But the diagram makes sense so thanks for posting that. I've decided to try out the BoB all direct and see what happens. If there is just one false e-stop I will add something like that - should be straight forward and there is plenty of space in the new control box I have planned out.

Thanks

irving2008
08-04-2014, 01:35 PM
The point I was making is that if your BOB has optoisolated inputs you can run these directly at 24v with 5kV isolation and all the noise immunity you need and saves all the hassle, adding an optoisolated relay doesn't 'make it better' just less reliable. Noise immunity is only an issue with non-isolated 5v BOB inputs.

.
Incidentally, if that is the circuit on that board then it has a potential noise immunity issue of its own unless used in a 'permanently energised' arrangement. With the diode not energised, the base of the output transistor, say Q1, is floating. Depending on the gain of Q1 a sufficiently large spike could briefly turn the transistor on and energise the relay. It should have a pull-down from the base to ground to prevent charge build-up on the base. A moot point and unlikely but not impossible.

JAZZCNC
08-04-2014, 01:43 PM
So would the automotive type be OK?
I also looked at solid state relays but will avoid on that advice. I quite like hearing a click anyway to confirm all is well.

Yes they would work ok provided contacts rating is correct but why not just use a Din rail mounted relay as they have proper clamp terminals and are easy to access and remove.
With relay either put a doide across coil or get the type which have one built in to stop back EMF. I prefer external diode then if it blows I can just change and they cost penny's not pounds like they want to charge extra for built in version.!!

irving2008
08-04-2014, 01:54 PM
With relay either put a doide across coil or get the type which have one built in to stop back EMF. I prefer external diode then if it blows I can just change and they cost penny's not pounds like they want to charge extra for built in version.!!

That's coz the diode in the relay is often a high current fast schottky diode with a known clamp voltage and thus guaranteed safe with almost any drive transistor, MOSFET, or IC - while I agree they don't cost s they aren't cheap and there's additional testing plus they save assembly and test costs elsewhere. An external diode would almost certainly be an 1N4xxx series of general purpose devices and cost pennies, plus if it gets disconnected more expensive driver could be compromised.

EddyCurrent
08-04-2014, 02:31 PM
Eddy,
Thank you, I did look at that as well but it talked about PIC and Arduino and I didn't know what to make of it. But the diagram makes sense so thanks for posting that. I've decided to try out the BoB all direct and see what happens. If there is just one false e-stop I will add something like that - should be straight forward and there is plenty of space in the new control box I have planned out.

Yes, the link was just to show where I got the diagram from.

@Irving, I have a board like the one in the diagram, there is a moveable link so that VCC can be tied to Gnd or JD-vcc

routercnc
08-05-2014, 11:27 PM
Few more bits for the upgrade parts.

Left = replaces some wooden parts which held the Z axis stepper motor, plus the Y axis ballscrew nut

Back right = Bracket which connects the new Z plate (20mm aluminium) to the Z ballnut

Front = Bracket which holds the bearing at the lower end of the Z ballscrew. Purpose designed compact unit to limit the amount of Z plate pocketing to retain Z plate stiffness. Machined the bearing pocket with a roughing cut, leaving 0.2mm dia undersize, then finished with full depth cut at final 20mm diameter. Really nice finish. Bearing arrived today (ID6xOD19xdepth6) and is a lovely gentle press fit into the bore. The end of the ballscrew will be turned down to leave a 6mm dia spigot.

12358

As you can see I like to print out some basic drawings with a few key dimensions on as I find this helps overcheck the machining etc. I've also started sketching the outline of the part on the blank with a felt pen to see where it will cut, where to clamp, make sure the machining is occuring roughly where it should be etc. All for now.

routercnc
02-06-2014, 09:46 PM
My VFD being out of action has stopped progress for now. I need to get the machine working to cut out the control panel, and some other parts. Whilst I sort that out I thought I'd keep the log going by showing these bits which arrived a while ago:

12510
DQ860MA drivers for X1, X2, Y (80V 7A) from Wantai
60V 10A power supply for drivers
12V power supply for relays, limits, home
Breakout board ('free' model which came with DQ860MA) - this is pretty basic and has no relays etc.
5off 12v relays with spade terminals - one master, 4 slaves
e-stop panel mount version
master on/off switch with power light
voltmeter (just for show really)

not shown:
Z axis retains existing MD542 driver at around 32v (re-using current bits which work fine)
3off proximity switches for homing
red 12V LED in bezel mount (to show e-stop condition)

Far from complete, here is current wiring layout:
12511
This assumes I upgrade the BoB as:
It is shown controlling the VFD speed
It is shown using BoB to run cooling fan and pump for spindle
It is shown running of 12v (free one is 5V)

Also drawn too many limit switches!

routercnc
25-11-2014, 10:19 PM
A couple of weeks ago I finished machining the final part for upgrade and disassembled the Y and Z axis. Here are a few photos of the new bits coming together.

1. Z stepper motor mount and side pieces which hold the Y axis ballscrew
13914

2. Z axis main plate
13915

3. Y axis main plate
13916

4. Z axis rails and ballscrew coming together
13917
13918

5. Converted a linear bearing housing to clamp the 80mm spindle (as posted by others on this site)
13919
Removed circlips, knocked out bearing, machined slot in one side, drilled 2 new holes to make 6 in total, counterbored to suit M8, job done.
Plan is to fit 2 long blocks onto the Z axis plate either side of this clamp so that if I ever index it up or down the Z axis it will remain aligned.

Still bits and pieces to tidy up, new spindle strain relief bracket to make, tidy hoses etc. but have already cut out my first new part and it does seem to be cutting better than before.

Might finish this thing one day . . .:whistle:

EddyCurrent
25-11-2014, 11:48 PM
Nice looking aluminium parts, it will be interesting to see how much improvement there has been, and maybe you could say which new parts made improvements and which parts did not.

njhussey
26-11-2014, 10:12 AM
Might finish this thing one day . . .:whistle:

Looking good, I can sympathise with the above sentiment....I keep trying to carry on with my build but work and other stuff keeps getting in the way...one day!!

Jonathan
26-11-2014, 02:16 PM
Didn't you measure the stiffness of this machine a few months ago? If so it would be interesting to compare the readings before and after the upgrade.

EddyCurrent
26-11-2014, 02:41 PM
Didn't you measure the stiffness of this machine a few months ago? If so it would be interesting to compare the readings before and after the upgrade.

http://www.mycncuk.com/threads/7155-stiffness-measurements-cnc-mk3?highlight=stiffness+measurement

routercnc
26-11-2014, 09:33 PM
Didn't you measure the stiffness of this machine a few months ago? If so it would be interesting to compare the readings before and after the upgrade.

Yes, I do plan to measure the stiffness again but it will be at the weekend at the earliest before I can get back in the garage.

Eddy, I've made all the changes together so won't be able to measure individual contributions but my best guess at where any improvements would come from are:

1. Y axis ballscrew plate changed from 18mm plywood to 20mm aluminium (forms part of the 'box' assembly at the top of the Y axis)
> Should improve Y direction stiffness

2. Z axis thin wall aluminium box section and plate arrangement with large offset from gantry changed to 20mm aluminium plate with pockets and lower gantry offset
> Should improve X direction stiffness, plus some Z and some Y due to having much less offset from the gantry

3. Spindle mounting bracket changed from a pair of 20mm thick clamping plates to a converted linear bearing housing
> Probably wasn't a limiting factor in the previous machine, but would in theory improve all 3 directions a bit.

Obviously don't try this at home but whilst I cut out my first part last weekend (from 10mm aluminium) I touched various parts of the machine and felt the vibrations. Not the most scientific method, but found the following, working back from the tool:

Spindle vibration high (not excessive or troubling but high relative to the other points)
Z axis plate vibration high
Z axis rail vibration fairly high
Z axis carraiges (which are on the Y axis) medium /medium low
Y axis assembly medium / low
Gantry low
Gantry sides low

In other words the biggest delta was across the Z axis linear profile bearings, in particular the top one which is the one further from the tool. These are 15mm units. If I was to start again I'd go with 20mm units as they are stiffer, plus they are a bit easier to mount (15mm rails take M3 bolts!), involve less pocketing, plus other general advantages.
But I'm pleased with the progress and if everything is as good as it can be and I've hit the limit of the rail then its not such a bad place to be.

Boyan Silyavski
29-11-2014, 03:06 AM
This seems quite an upgrade to me. Plus more pleasing to the eye, call me crazy but that's quite important to me.

routercnc
02-02-2015, 09:56 PM
Before you ask - no I still haven't measured the stiffness of the new machine! But I have managed to make progress on the semi-automatic dust shoe system, and as you can see it is making nice cuts in aluminium.

The bits assembled on the bench. Used 12mm stainless rod and linear bearings for the rise and fall bits.
14581:

I posted ages ago about the concept in another post, but made more sense to tack it on the end of this. To re-cap,

Bit changes
The dust shoe has a removable lower section, held on by magnets plus located by the ends of the support rods. This is to allow easy bit changes. It also allows a variety of dust shoes to be fitted depending upon the job.

Semi-automatic height adjustment
It is attached to the Y axis, not the Z axis, so it does not simply rise and fall with the cutter. Instead there are 2 adjustable knobs, one to control the maximum raised position, and one to control the maximum lowered position.

Initially at the home (or raised Z position) the dust shoe is held up by the lower adjustment tab, which rides on top of the spindle body. When the cutter drops down the dust shoe drops with it.

As the cutter approaches the cutting position the upper knob and stop-collar prevent the dust shoe falling any further, being set to be just above the top of the workpiece (say 2mm). During cutting, even deep plunging, the dust shoe is always at 2mm above the workpiece irrespective of cutting depth as the spindle moves independantly of the dust shoe. This should make it good at collecting dust, and avoid the problem of crushed brushes or brushes being sucked into the extractor or cut with the cutter etc.

When the cut is finished the Z axis raises up and at some point collects the dust shoe tab which raises the dust shoe as well. It is then ready for a bit change, or the next cut.

Here are the parts fitted to the machine:
14582

Here is a close up showing the 2 adjustors for the max and min height adjustors.
14583

Still have to cut a short length of 100mm duct to fit between the lower part and the fixed part, plus add the 100mm duct from the extractor machine, but you should get the idea. All sounds OK in theory so will let you know if it actually works!

Boyan Silyavski
02-02-2015, 10:28 PM
Very nice idea with the dust shoe. if you use some advanced CAM you could control all tool paths so no problem will arise. It seems even with simpler CAM it should work ok.

By the way i have a very similar dust shoe setup, only thing is that it does not slide like yours. Biggest problem i have encountered is when something chips and stucks in the section between the spindle and the vacuum hose. But my dust shoe seems not so deep like yours. So your should work better. i believe this dust shoe design will work better with short brush

EddyCurrent
03-02-2015, 10:29 AM
Nice looking dust shoe, I need to study it better when I get time. I liked this idea, don't know if it can be applied to your; https://www.youtube.com/watch?v=tBzoQw4du8E

routercnc
04-02-2015, 08:11 AM
@Silyavski
I guess you mean CAM toolpath control to avoid any clamps? I have some low profile clamps so should be OK there.
With regard to adding brushes - yes I've considered that and with the lower plate being removable I can try different designs and use the best one for the job.

@Eddy,
Thanks for the link to the video. He does go on a bit! During cutting mine will behave a bit like that, but with the advantage of rising up out of the way when the cut is finished. His looked static from what I could tell.
Also, the lower plate on his is completely open, whereas mine is only open locally around the cutting bit so should give better extraction. I also think my magnetic removable plate means it is quick to get everything out of the way and change over to jobs which don't really need a dust shoe such as aluminium machining.

EddyCurrent
04-02-2015, 12:26 PM
Eddy,
Thanks for the link to the video. He does go on a bit! During cutting mine will behave a bit like that, but with the advantage of rising up out of the way when the cut is finished. His looked static from what I could tell.
Also, the lower plate on his is completely open, whereas mine is only open locally around the cutting bit so should give better extraction. I also think my magnetic removable plate means it is quick to get everything out of the way and change over to jobs which don't really need a dust shoe such as aluminium machining.

The only aspect I was drawing your attention to was the piece of 4" flexible ducting around the spindle collet area

routercnc
04-02-2015, 01:24 PM
I'd glossed over that but you are right - that is a good feature and would improve dust collection still further. I don't think I could fit 4" hose, but something smaller in diameter and just tall enough to make a seal with the spindle during cutting should work. I'll look into it . . .

routercnc
04-03-2015, 10:50 PM
Some progress. Putting my hand under the extractor shoe feel likes a reasonable draft so I think it will do the job.

I won't be cutting anything for a bit as I've decommisioned the control box to make the new upgraded version. Here is the old control box - low voltage basic all-in-one system which has run well for over 5 years now, but time for an upgrade:
14808
It was pretty clean inside as you can see so the filter on the left was doing its job well.

Here is the revised electrical layout - the one I posted a while back would not have worked as the relays were linked in series! There are some other 'improvements' as well:
14809

Here is the progress on the new control box:
14807

As you can see I was inspired by Eddy's control box to make a better job of it this time round.

Top row left to right:
Invertor/VFD 1.5kW
12V PSU (ancillaries, BOB, safety relay and limits)
60V 10A PSU for X1, X2, Y2 drivers
32V PSU for Z driver (out of old machine)

Next row:
permanent 12V terminal block
permanent 0V terminal block
relay switched 12V terminal block (the photo is now out of date as I had intended to use this as a 5V terminal block)
Master relay with 4 outputs - latching function, driver relay control, BOB e-stop trip, Spindle run inhibit
4off 30A automotive relays (5pin) to control the drivers
star earth point terminal block

Final row:
Breakout Board - Fairly cheap board (~10 ebay) but with space for something much bigger/better should the need arise(!)
3off DQ860MA 80V drivers for X1, X2, Y1
1off MD542 48V driver for Z

Tool collection so far - That bootlace ferrule tool (orange) makes a really nice job of the cable terminations, thank you to those who recommended that route:
14812

I've posted the front control panel in another post but will repeat it here for completeness:
14810

I've ordered the Pokeys board which will fix to the back of this control panel, keeping all the wiring local on the front panel and just leaving the USB to run to the main board. This will control the feed start/pause/stop/rewind, feedrate override, and feedrate reset in Mach3 using the Pokeys plugin. All other functions will be hardwired in simple circuits.

Now a question on the relays. Earlier in this post I asked about diodes across the coil - 1Nxxxx series was mentioned but when I looked this up recently there were so many to choose from! So I did a google search specifically on suitable diodes and found mention of an SR5100 5A 100V Shottky Diode so bought a set of 5 for about 2 as I was buying some other stuff anyway. Before I fit these to the relays are they suitable?
14811
Can someone confirm that the grey bar on the part is the 'bar' in a diode symbol and that this faces the positive end of the relay - see layout diagram.

Boyan Silyavski
04-03-2015, 11:28 PM
Just some random thoughts on buttons.

I was thinking adding the same buttons. Though i don't see a reason for spindle controls there. Its clearly seen on the mach3 screens/ok i have MSM Mill screen /, or at the VFD/if you have it on the wall like me/.

I see the need though of these buttons, most are same as yours, ordered by importance / to me at least/. Mist flood and vacuum are last, as these are controlled via the program and relays or/and manually turning valves.


Reset

Start
Hold
Stop

Find Zero Z /Touch plate/
REF ALL

Go to XY0
Go to Z0
Go to TC position
Go to Park position


Mist
Flood
Vacuum

routercnc
05-03-2015, 08:09 AM
silyavski,

I think in the end it comes down to how you use the machine and personal preference. I looked at lots of commercial panels to see what could be useful and ended up after many different options with the panel above.

The VFD will be inside the cabinet so I can't see the screen. I've not been able to find a long extension cable to detach the panel and put it on the door. Any links to one welcome!

Although there is control for VFD on/off, it is also under Mach3 control for on/off so it is just a manual override option.
I thought about Mach3 spindle speed control and in the end just went for the manual pot direct to the VFD. I tend to cut the same things at the same speed. It would be very easy to get Mach to also control the speed and then wire the pot to the Pokey system if I change my mind. Keeping it simple for now.

My buttons are laid out in order of running sequence left to right. Power on, then e-stop reset to energise the relays, then switch on lights and pumps if required, then start the spindle and set the speed, then run the cycle, with a feedrate override tuning dial right at the end.

I have a seperate MPG pendant so no need to add controls on the panel.

That's my version anyway . . .

routercnc
06-03-2015, 11:04 PM
Managed to get a bit more done tonight:
14823

14824

Wired up the safety relay and the 4 slaves, plus the panel e-stop, the e-stop reset button and e-stop red LED. Triple checked all the wiring, stood back, held my breath and switched it on at the wall. The PSUs came on and the BOB came on.

Then switched the 12V power switch and the e-stop went into standby and the red LED came on. Excellent. I then pressed the reset button and the safety relay clicked along with all 4 slaves (also the red e-stop LED went out). Everything worked perfectly!

Decided to leave on a high and carry on later this weekend if I get a slot. Oh and to answer my own question the diode bar goes to the positive side of the relay to provide flyback control.

GEOFFREY
07-03-2015, 07:38 PM
I have been watching this post for a long time now, and everthing seems to be coming together beautifully. I don't think it will be too long now before chips are really flying. Great job. Well done. G.

routercnc
08-03-2015, 11:39 AM
Thanks for the encouragement Geoffrey!
Got the latching bit working on the master relay so it stays on when reset and trips out on estop button being pressed.
Got power to the first 2 drivers via the relays so starting to come together.

Very pleased that it is working as per my original electrical plan. One thing that bothers me is that if I power up the spindle manually and there is an estop then the inhibit relay will tell the VFD to stop. All good except when I reset the fault the spindle will come on straight away. something for me to watch if I use it manually

Most of the time the spindle on/off will be under mach3 control and I'm expecting the relay on the BOB to trip if there is an estop so no problem. Does anyone know if the Bob will trip the spindle relay if there is an estop?

routercnc
24-03-2015, 10:29 PM
Quick update.

Got the main panel on the wall and wired up all the stepper motors. I have changed over from series to parallel connections (on the X1,X2,&Y motors) to take advantage of the higher current available from the new drivers. I decided to solder and heat shrink the cables at the stepper motor end and dispense with the choc-block. One less terminal to come loose. Here it is before the final large heat shrink was placed over the cables:
14950

At the other end I re-did the connnectors including new earth cables to the outer screen. It all looked rather neat and tidy. Panel on wall (box sides and front to follow):
14951
(note stepper motors are un-plugged in photo)

Here is the loom I made up to join the BOB to the steppers:
14952

I then spent (wasted!) many hours this weekend trying to get the breakout board to talk to the stepper drivers. I checked the output from the direction pins and got around 4V or 0V depending upon direction. I wondered if this was a bit low so unplugged the USB lead and found a 5V source in the PC and made up a cable to connect to the 5V and GND pins instead. Got 5V output this time on the direction pins, but still no stepper movement.

I checked and double checked all the wiring, tried common anode and common cathode connections but still nothing. Checked all the Mach3 settings and they were all correct. Tried various things but to no avail. Borrowed an oscilloscope tonight and connected to the BOB pins. Direction still gave 5V or 0V but no pulse-train out of the step pins.

This was the BOB I was using - it was about 8 from ebay:
14948

In frustration I wired up the one which came free with the drivers:
14949

5V and GND from the PC, then pins 2 & 3 for step and direction and got a pulse-train! Plugged the driver back in one axis and the stepper moved ! So this will have to do to get it moving again with the new steppers. From that quick test it sounds much better than my all-in-one board if that is anything to go by.

I need to make up some proper looms for the bits I lashed up to get the new board working, but that should be straightforward.

The new board is very simple with no relays, speed control etc. so once I'm running I'll be looking into better boards with more features. There are a couple on my list such as the PMDX126, but not rushing into things.

routercnc
30-03-2015, 11:10 PM
The saga continues!

On Sunday morning I managed to finish the last bit of basic wiring and set up all the motor tuning etc. Managed to achieve 2500mm/min - 3000mm/min jog speed before stalling, so settled on a safe 2000mm/min on X & Y to get it all going. Old machine ran at 1000mm/min so a great step forward.

I set out the machine to cut the 3mm aluminium front panel out to house all the controls. Fired up the spindle, hit cycle start and it started to cut the first circle. About 3 seconds into the cut there was a large bang and blue flash from the 60V 10A SMPS. This was the supply to the X, A and Y drivers (Z is only its own driver and supply).

After a bit of head scratch I realised that in my haste to get things going I'd left the 3off drivers on the factory default current setting of around 7.8A peak (5.6A RMS). As the power supply is rated at 10A I guess that was too much! Annoyingly the fuse inside the power supply was not blown, so I guess the whole thing is dead. I bought the PSU early last year, and I can't see another one of that spec on ebay, so that is that.

So, been doing a bit of research and will most likely build my own linear power supply for the X, A, and Y axes. Here is where I'm at with it:

Stepper motors - M60STH88-3008DF x 3off, 3.1Nm, 2.1A per phase (4.2 total), 5.46V
Drivers - DQ860MA 3off, 80V max

Toriod calculations
Nominal current draw = 3off x 2 phases x 2.1A per phase = 12.6A
Actual real draw = 0.7 x 12.6 = 9A
Required output to drivers = 68V (with margin for back EMF etc.)
Secondary voltage in coil = 68 / 1.4 = 48V AC
Toroid wired in series = 24 + 24
Power requirement = 48V x 9A = 432 Watts (432 VA)
Power with overhead in case of 4th axis = 750 Watts (750 VA)

Model selected: 750VA 230v to 2x24v CM0750224 from airlink at 48.00
15027

Power regulator
For simplicity I'm looking at these power regulator boards at 29.00+6.99 postage ebay. I know 60,000uF 100V is more than required but it was not much more than the 40,000uF 100V system.
15028

Input fuse
I'm not completely sure on this but am looking at a 6A Type D MCB double throw fuse to switch the Live and Neutral into the toroid. Do I need to match the 9A real current draw or do I go lower? This 6A one is from Chalon at 7.18:
15029

Output fuse
Is this required, and what would be the best type and rating to use?

Any thoughts on the above spec? thanks.

routercnc
31-03-2015, 11:25 PM
I've redrawn the circuit diagram with a few planned updates. What I'm stuck on is:

Question 1: Choosing values and types of fuse for the input mains side of the power supplies:
3 power supplies requiring input protection are:
1. Planned new linear supply for X, A, Y axes, @750VA, pulling up to 9A (4.1A parallel 3.1Nm steppers x 3off x 70%)
2. Existing SMPS for Z axis is 350W pulling about 1-2A (2A series 1.8Nm stepper x 1off x 70%)
3. Existing SMPS for ancillaries is 12V, 60W, 5A

What to choose for each of the 3 above power supply mains inputs:
> Use MCB din rail mounted double throw?
> What type (A,B,C,D) to choose to avoid trip on inrush?
> What current level to choose?

Question 2: Choosing fuse values for DC output side of supplies
1. Linear supply on X,A,Y could pull up to 4A per motor - choose 5A blade fuse to each stepper?
2. SMPS on Z could pull up to 2A - choose 3A blade fuse?
3. SMPS for ancillaries rated at 5A - just go with 5A blade fuse?

If it helps here is the updated schematic, with the required new fuses / MCBs shown in RED (ignore ratings and type, those are some ideas which I'd like confirming):
15047

Question 3: Setting current rating on DQ860MA drivers
Stepper motors are rated at 2.1A per phase so 4.2A total. Current setting options are either PEAK or RMS. Which to choose on the driver dip settings? Is it 4.2A PEAK or 4.0A RMS?
15048

Question 4: Do the toriod and power regulator calcs in the previous post seem OK?

Sorry for all the questions . . .

routercnc
03-04-2015, 11:07 PM
I ordered the toroid (750VA, 2x24v), power regulator board (60,000uF 100V capacitors, 20A rectifier), double pole MCBs for each power supply of various current rating with type D trip, DIN rail, DC fuse box holders.

Whilst waiting for this stuff to arrive I looked again at the blown SMPS and noticed a tiny glass fuse tucked away in the corner and soldered direct to the PCB (F2 - photo shows it removed).
15100

15097

It was clearly blown with black on the glass. I managed to cut the legs and get it out to read the rating and it looked like 250V 15A (printing was faint so not sure) about 3.5mm wide and 10mm long. Bit of searching revealed it was called an axial lead fuse and only they cost a few pounds for a pack of 4. Started to wonder if I could repair it and get the machine running for now until the linear supply was here and built. So I took the board out but discovered alot of damage underneath, some of them were charred surface mounted components. Even if I replaced the fuse and it worked would I trust it? Decided not.
15098

15099

So I need to wait a few weeks for all the new linear bits to arrive. No doubt I'll post any questions I have at that time so I don't get any more blue flashes. All for now.

routercnc
11-04-2015, 09:57 PM
All the bits arrived in double quick time. Now I need some help confirming the wiring colours and general connections.

Here is the toroid: 750VA 2x24 from airlink
15132

Here is the power regulator (60,000uF, 100V, 20A rectifier):
15133


Here is a circuit I've drawn up but need help with:
1. Toroid blue and brown I assume are mains input?
2. 4 output wires are from the pair of windings? - but which to connect to the regulator and in which order?
3. I'll mount all this on an aluminium plate which will go to earth - does the centre GND output on the DC side need to be earthed as well?
15134

I'm away from the parts at the moment otherwise I would at least give you the resistance readings across the toroid wires, but hopefully the above is enough.

Thanks

Boyan Silyavski
11-04-2015, 10:20 PM
I had similar parts wired like that http://www.mycncuk.com/threads/7659-PSU-wiring-help-needed?p=59481#post59481

Hope that helps

Jonathan
11-04-2015, 10:22 PM
Here is a circuit I've drawn up but need help with:
1. Toroid blue and brown I assume are mains input?

Likely yes, but it should say on the transformer itself.


2. 4 output wires are from the pair of windings? - but which to connect to the regulator and in which order?

The capacitor arrangement you have is intended to obtain a positive and negative voltage, not the single supply that you require. To use the board as-is, you could connect both secondary windings in series to AC1 and AC4, but you'll then have 3 capacitors in parallel with two in series, so only 10000*3/2=15000uF. That may be sufficent ... but it's a bit of a waste when you could modify the board to have all 6 capacitors in parallel to get 60000uF.

routercnc
12-04-2015, 08:21 PM
Silyavski,
Thank you for that link - very good reading. Based on Jonathan's comments and your selection of the 40,000uF model then based on Neil's suggestion then you might only be getting 10,000uF (10,000uF x 2 /2). Any issues with running like that on your machine? If I use my board as-is then I'll only get 15,000uF.

Jonathan,
Thank you. I briefly looked at the toroid when it arrived to make sure all was intact and didn't notice the sticker on the side!
15136

As for modifying the board to get the full 60,000uF - the tracks are 'painted over' ; either that or it is a multilayer board because apart from the solder points there are no exposed tracks on the top or bottom. I'd probably have to demount the capacitors and run flying leads to them from the output of the rectifier.

Had a couple of minutes spare today so checked the output from the secondary coils:
15137
Mains was 243V AC and each secondary coil was 26.4V AC

I need to wire the secondarys in series but cannot find any markings on the cables to show which is the start of the winding. I've read that it does not matter how they are connected (unlike parallel which is vital). Can someone confirm this is the case?

Jonathan
13-04-2015, 01:47 PM
Silyavski,
Thank you for that link - very good reading. Based on Jonathan's comments and your selection of the 40,000uF model then based on Neil's suggestion then you might only be getting 10,000uF (10,000uF x 2 /2).

Sounds like it to me.


Any issues with running like that on your machine? If I use my board as-is then I'll only get 15,000uF.

Sizing the capacitors is quite tricky - there are formulas floating about on forums, but prizes for finding one with some derivation or reference, not just a rule-of-thumb. You can easily calculate the voltage ripple on the capacitors for a known current (V=I/(C*f)), but what current do you use and what voltage ripple is acceptable? We can get a reasonable idea of the input current from the motor power ratings, but even then it's a bit of a guess as to what voltage ripple the stepper driver will tolerate. You could look at it in terms of what voltage (and hence current) ripple the capacitors will tolerate, or define some minimum input voltage from the transformer you'll allow and go from there. I'd probably go with the former...then take an educated guess!

For a while I had my machine running 4 motors from a 500VA transformer with 11000uF capacitance and I noticed an improvement in obtainable feedrates when I moved one motor to another (320VA) transformer and left the original transformer and capacitors with just 3 motors. So maybe 15000uF is fine ... bit subjective though as I didn't take any readings to verify.


As for modifying the board to get the full 60,000uF - the tracks are 'painted over' ; either that or it is a multilayer board because apart from the solder points there are no exposed tracks on the top or bottom. I'd probably have to demount the capacitors and run flying leads to them from the output of the rectifier.

That's a shame. Do you have a working CNC router, or is this your first? If you want I can send you the dxf to make these ... it's very simple:


http://www.mycncuk.com/attachment.php?attachmentid=15139&stc=1

Or we could do some sort of swap.


Mains was 243V AC and each secondary coil was 26.4V AC

That's normal - they are a bit high as the rating is when loaded.


I need to wire the secondarys in series but cannot find any markings on the cables to show which is the start of the winding. I've read that it does not matter how they are connected (unlike parallel which is vital). Can someone confirm this is the case?

Not the case. If you get them the wrong way round, the voltages will cancel out and you'll get approximately zero. I would guess that the order they are written on the label is indicative of their polarity, so try connecting red to orange and measure the open circuit voltage between black and yellow.

routercnc
13-04-2015, 10:18 PM
Hi Jonathan,

Thank you for taking time to write that comprehensive reply. I'd done a bit of thinking on the series connections and quickly realised that one way would be ~0V and the other way ~50V AC ! So thank you for confirming that. I'll try connecting as you suggest - its either one way or the other and at least being series it won't matter if I get it wrong.

Had another look at the regulator board and I can now see some tracks but am not confident I could make a safe job of modifying it.
15145
15146
15147

So I've also decided to de-mount the capacitors and build a more conventional system. I've ordered:
Solder sucker (had one years ago but can't find it ~4)
35mm diameter capacitor clamps (6off ~1.50 for a pair)
400V 35A rectifier centre bolt mounted (~3)

Thank you for the kind offer to swap / supply dwgs for the capacitor circuit but I'm going to go for the traditional route of mounting each capacitor in the plastic mounts (inverted) and solder cables between the pins. It looks like there will be about 3mm of pin remaining from the top of the caps which should be enough to a cable get onto. The rectifier will be the traditional 4 spade pin type. All bits will be mounted to a ~4mm aluminium plate for heat dissipation and general sturdiness.

That's good background info on the ripple voltage. I had started to wonder about what an acceptable level would be. More capacitors will be better with lower ripple but I guess gives more in-rush current so more chance of tripping the MCB on start up. At least I can play around with the number of capacitors if I have that problem. But if it just works then I'll leave it and get on with using the machine.

For info this is my 3rd generation of cnc machine, with many minor iterations of development along the way, but it remains my only cnc machine and is currently out of action until the PSU if fixed.

Jonathan
13-04-2015, 11:22 PM
Don't you just hate black soldermask :|

If you remove three of the capacitors that are in parallel, then put them back in the other way round, you will have one terminal of all 6 connected, so just one piece of wire will be needed to connect the '+VCC' and '-VCC' terminals to have the capacitors in parallel. If you can break one track on the PCB and add one piece of wire, then you can use the existing diodes.



More capacitors will be better with lower ripple but I guess gives more in-rush current so more chance of tripping the MCB on start up. At least I can play around with the number of capacitors if I have that problem. But if it just works then I'll leave it and get on with using the machine.

Yes, we'll see - you will have a lot of capacitance. I looked at that situation recently with my motor drive - that's got 660uF @ ~340V and with direct connection to the mains the scope showed that the current peaks at about 15-30A depending on the timing. That still doesn't blow a 6.3A slow blow fuse though, as the duration is only a few milliseconds.

routercnc
15-04-2015, 10:45 PM
Hi Jonathan,

Thank you again. I had to draw out your idea of reversing the capacitors before I could see how it could work. I considered it for quite a while but in the end was concerned about breaking the tracks and adding flying leads. I've had enough of blue flashes and bangs.

I've managed to remove the capacitors from the board. Looks like there is plenty of remaining pin to solder the cable to:
15148

Capacitor mounting brackets and a new rectifier should be here by the weekend so I will lay it all out on the mounting plate if I get the opportunity.

I've decided for reasons of space (6off 10,000uF caps with mounting brackets takes up a surprising amount of space!) and in-rush current to go with 40,000uF as a starting point.

I'll report back with success or more questions . . .

One more thing, I've added a safety latch relay for the spindle inhibit. This makes sure that if there is an e-stop (which stops everything including the spindle) that when the e-stop is cleared the spindle does not fire up until the start button is deliberately pressed again. Ordered 2 pole DIN relay for this job. Drawing updated:
15149

routercnc
16-04-2015, 11:36 PM
Based on a discussion I was having in another thread (but didn't want to hijack) my plan is to remove power directly from the drivers in the event of an e-stop via relays.

But as the steppers a likely to be moving then is this is problem for the drivers? I'm sending an e-stop to the BOB at the same time so the motors should be in the process of stopping.

Would it help if I added a capacitor across the relay coils to slightly delay driver shut down prior to the motors coming to rest - just a few milliseconds? Or am I worrying over nothing?

Does anyone else remove power to the drivers using relays in the event of an e-stop?

JAZZCNC
17-04-2015, 10:18 AM
Or am I worrying over nothing?

Does anyone else remove power to the drivers using relays in the event of an e-stop?

Yes your worrying over nothing.!!! . . . If you remove signals so no pulses are still getting thru while caps drain then just turning off the power will be enough and motors will come to stop quick enough.

Edit: If you do want to go a little OTT then have e-stop turn off drive Enables so motors are still under torque and stop quick then remove power second or two later using a timer relay.!!

routercnc
17-04-2015, 06:22 PM
Hi Dean

In my layout (see post above) my relays are AFTER the PSU so there are no caps to drain and the drivers loose power immediately. So I either leave it, change to a relay BEFORE the PSU on the mains side which I think is what you are referring to, or add delay / capacitor across the existing driver relays on the DC side to hold them closed for a few milliseconds. Hope this distinction makes sense.

JAZZCNC
17-04-2015, 06:50 PM
Well my way is to remove power by dropping out a contactor to transformer and send signal to control informing about e-stop so halting pulses.!

But in all honest your setup won't be a problem unless you intend traveling at high velocity and have a heavy gantry. So if you have it wired then wouldn't worry.!

routercnc
17-04-2015, 11:39 PM
Ok, good to know thank you. Gantry is pretty light and feedrates aren't that high.

Capacitor mount brackets arrived today so roughly laid it out on the aluminium plate. Plate will be trimmed off just after caps, and before MCB.

I noticed that the toroid 2x24V AC cables are a much heavier gauge than the 240V AC cables so I'll match that heavy gauge with the DC cable out of the rectifier and over the caps.
15161

It's a bit bigger than the blown SMPS it replaces but should still just about fit in the cabinet, top centre:
15162

routercnc
18-04-2015, 11:02 PM
Joined the red and orange together and got 54V AC across the black and yellow, so that is the correct series connection.
15163

I cut the red and orange cables back to leave about 60mm showing, stripped and tinned then ends then soldered together. Heatshrink over the join, then another long heat shrink over the top to finish the series connection.

Crimped terminal ends on the black and yellow cables for the rectifier. Had a look at the datasheet and the terminal rotated 90 degrees to the other 3 is the DC + output. Diagonally opposite this is the DC - output. The other 2 are AC inputs.
15164

Marked out the holes for the cap brackets, rectifier, toroid and corner bolts and started drilling a few out. Went with M4 tapped on the capacitor bolts. Getting there slowly . . .
15165

The MCB hasn't tripped out yet on the few times I've turned it on (6A type D) but since I haven't connected the capacitors yet that probably doesn't mean much.

njhussey
19-04-2015, 09:01 AM
Joined the red and orange together and got 54V AC across the black and yellow, so that is the correct series connection.
15163

I cut the red and orange cables back to leave about 60mm showing, stripped and tinned then ends then soldered together. Heatshrink over the join, then another long heat shrink over the top to finish the series connection.

Crimped terminal ends on the black and yellow cables for the rectifier. Had a look at the datasheet and the terminal rotated 90 degrees to the other 3 is the DC + output. Diagonally opposite this is the DC - output. The other 2 are AC inputs.
15164

Marked out the holes for the cap brackets, rectifier, toroid and corner bolts and started drilling a few out. Went with M4 tapped on the capacitor bolts. Getting there slowly . . .
15165

The MCB hasn't tripped out yet on the few times I've turned it on (6A type D) but since I haven't connected the capacitors yet that probably doesn't mean much.
This was the way I joined my transformer from the technical description on the airlink website...

http://images.tapatalk-cdn.com/15/04/18/1ced54d861edcbf3b0b969d83690b7e7.jpg

JAZZCNC
19-04-2015, 09:23 AM
Joined the red and orange together and got 54V AC across the black and yellow, so that is the correct series connection.
15163

Like the Wood.!!. . . . This way you can Bat your self with it when you electricute your self.!. .Lol:joker:

routercnc
19-04-2015, 03:29 PM
Doh! I've cut the red and Orange back quite short and soldered them together. Can someone tell me if it matters this way around instead of Neil's picture ?
Thanks

JAZZCNC
19-04-2015, 03:41 PM
Doh! I've cut the red and Orange back quite short and soldered them together. Can someone tell me if it matters this way around instead of Neil's picture ?
Thanks

Doesn't matter.!

routercnc
19-04-2015, 04:21 PM
Dean you are a star thankyou!:encouragement:

And the wood was to make it easier to touch the end of cables with the multimeter - don't like zapping myself!

routercnc
02-05-2015, 11:29 PM
Bit of an update.

Wired up the PSU caps last weekend and did a final check before switch on. so glad I did because I noticed that for some reason I'd connected the black cable to the positive side of the caps and red/white to the negative! I dread to think what would have happened if I'd switched on. I know electrolytics don't like that sort of thing and have seen small ones explode and unravel. These ones are much bigger! I always wear eye protection in the garage whatever I'm doing but it still would not have been pleasant.

So I switched the spade terminals over out of the rectifier so -ve went to -ve on the caps etc and switched on. Got 72V DC output so was happy with that. The type D 6A MCB did not trip so another good sign. I switched off and unplugged everything.

I then thought about re-soldering the cap cables so I wouldn't get confused with the wire colours if I needed to change anything in the future, but realised I had a problem. There was 70V DC stuck in the caps and the cables were therefore live. I tried discharging them by touching them on the power supply pins of one of the drivers but got a blue spark. I think this was because I couldn't really make a quick decent connection on the bare wire touching a small pin rather than anything untoward.

In the end I de-soldered one of the 10k resistors from the power module board (that held the capacitors) and managed to wedge/rest it across the pins of one of the caps. It took about 1 hour to discharge to 0V, probably not helped by the contact being quite light between the resistor and the capacitor.

This did get my thinking though about the voltage that the 12V DC relays would be switching across their terminals, and I wondered about the lifespan of the contacts. This coupled with the fact that if I e-stop the machine then there would be 70V DC floating around in the control box. So, the relays all came out and the drivers will be hardwired to the PSU. This solves both problems in one.

The PSU will be switched by a 25A SSR which is now on order. I looked for a contactor but they are all 24V and I only have 12V. I thought about changing to 24V but then would need to consider the LEDs, the pump, and cooling fans etc which are all 12V. So staying with 12V assuming SSR does the job. Here is the updated wiring drawing:
15258
[ edit - spotted some copy/paste errors in the layout diagram above since posting so have corrected those ]

I've also just received a few more bits from Chalon components to form a second rail to house most of the DC side including power distribution, safety relays, etc. Here is an update of the control box layout:
15257

routercnc
04-05-2015, 10:06 PM
Did a bit more today.

15259
Top left space is for 12V SMPS and VFD


I decided to use the DIN rail as the star earth point (instead of a small block I had in the corner of the cabinet) and am now using proper DIN earth terminals to connect up all the earths.
15263

I've also added a lower DIN rail which is for DC, leaving the upper for mostly AC. I've also split out the main PSU positive into 3 feeds which will run down to the fuses on the new lower DIN rail and then into the drivers.
The old DC terminal blocks for 12V, 0V, and 12V 'switched' are gone and have been replaced by DIN rail terminal blocks (blue). I looked at all sorts of options here and went with these in the end. This type are actually meant for AC neutral so will be labelled clearly as 12V DC, 0V DC, and 12V switched.
The master relay and spindle inhibit relay are now on the DC DIN rail next to them.
15260

The drivers have been moved down a bit and the trunking run around them. The BOB has plenty of space in case it starts mis-behaving and needs to be replaced.
15261

The power supply has been wired up correctly (!) - still need to split out the black 0V cable into 3 feeds and tidy up the general wiring but otherwise PSU is nearly done. As reported previously it all works.
15262

More terminal blocks are on order! All for now . . .

GEOFFREY
05-05-2015, 09:05 PM
That looks very neat and professional. Well done. G.

routercnc
05-05-2015, 10:04 PM
Thanks Geoffrey,

Starting to enjoy the electronics but would really like to finish it soon !

Can anyone confirm that using an SSR (25A) is OK to control the 2 power supplys? My plan is to apply 12V DC across the DC side and switch the 240V AC supply of the live cable to the 72V linear power supply primary, and also to the live cable of the 32V SMPS.
15280

I understand that when SSRs are 'off' there is still a small voltage which passes through the AC side so in theory the drivers are still powered, although the voltage is very small. Is this the case and should I be concerned about it? Should I add anything else?

I also understand that an SSR works well with pure resistive loads - but I think the linear supply is a heavily inductive load with voltage and current out of phase. Is this the case and again is it a problem for these SSR devices?

I don't know what type of load the SMPS is but again will this switch well with the SSR?

See post #62 for the circuit diagram - the SSR is slightly right of centre.

This is a sketch of where it will be located (red rectangle):
15281

Thanks for your help

routercnc
11-05-2015, 08:42 PM
OK, I've added the 25A SSR but am not sure it is the right device to use to switch the linear supply. Here's why . . .

The SSR is connected to the e-stop circuit to cut or supply power to the driver power suppliers. To test it out I tried it on the driver supplies one at a time. When I just connected it to the SMPS (30V) it all worked fine (on the one time I tried it). But when I connected it to the linear power supply (750VA coil, 40,000uF caps, 72V output) the MCB tripped (6A type D). Previously on the couple of times I tried it without the SSR it did not trip.

I'm now convinced that the SSR is not the right switching device for linear supplies due to the high inductance of the load, but I'd welcome a second opinion. I've been hesitating using a contactor because they all seem to be 24V and my box runs 12V. But I now think it is the only way so I'll have to modify all the 12V items to work with 24V. I did look at 12V to 24V DC-DC convertors but didn't like the idea of running it for extended periods to hold the contactor closed. Plus, I think they give out electrical noise?

So to convert the box to 24V needs a resistor for the 12V LED, and either resistors for the mechanical relays, or most likely swap them out for 24V versions. The pump and lights are 12V each so I can add them in series and switch both at once (instead of independently).

So the big question is what current rating of contactor do I need to switch the big linear supply (X,A,Y axes) and the SMPS (Z axis)? I'm guessing many tens of amps at least? The inrush current on this linear supply is quite high I suspect but the online calculations for current spec seem very involved. Does anyone have an idea of what to use? I don't want to run it for a bit then burn it out.

Thanks

njhussey
11-05-2015, 10:02 PM
I think I've got this one...http://chaloncomponents.co.uk/epages/5ce70930-822f-444b-90aa-ca3e0dcdcc0e.sf/en_GB/?ObjectPath=/Shops/5ce70930-822f-444b-90aa-ca3e0dcdcc0e/Products/NC1-1210Z but without looking at either it of the paperwork I can't be 100%. My PSU is a 625VA unit and also going through it is the 230V Nema 34 driver and 24V PSU.

I'm sure someone far more electrickery minded will pop along soon!

routercnc
11-05-2015, 10:45 PM
Hi Neil

Thanks for that. Google search shows this is 12A which I think would be ok for continuous running just not sure about the inrush. Is yours powered up yet and running everything connected to it without problems? Thanks

njhussey
12-05-2015, 11:22 AM
Unfortunately mine's had nothing done on it in the last 2 and a bit weeks as one of my colleagues (there's only 3 of us in the office) is on long term sick so I'm now doing all the design and engineering as well as all the other stuff I normally do so this has taken a backseat :thumbdown:

I got the 12A one as I was going to put a soft start on my torroid....not got round to that yet. I'll probably do it if I have problems.....

routercnc
13-05-2015, 10:52 PM
Hi Neil,

Sorry to hear that - it's so close to being finished.

On my machine I've re-drawn my circuit diagram to run the control side from 24V DC instead of 12V. I've ordered a 24V 5A SMPS and 2off 24V 4PDT DIN relays, laid out the 12V cooling pump and fan in series to give 24V load, and will drop a resistor (680ohm 1/2 Watt) onto the 12V LED line.
15314

Those are the easy bits. But can anyone out there help with the following? I'm missing the contactor to switch on the 70V linear power supply and 30V SMPS for the 4 drivers. This will connect after the 6A type D MCB. I keep reading around on this and am getting no-where. There are 2 problems:

One is that I can't find a simple way to work out the inrush current on the power supply so don't know the peak current rating for the contactor.

Second is that contactors appear to be rated for different applications, labelled AC1, AC2,AC3 .. .AC6a, AC6b . . . For example AC3 is for motors, AC6a is for transformers etc. I can't seem to find any that are 24V DC coil with AC6a rating. All are AC3 rating which is really for motors?

I noticed Dean posted a drawing in Neil's build log (e-stop circuit) with a 25A contactor so that is my starting point. Is this an AC3 unit? If so does this work OK with a high inductive load such as the transformer?

All real world experiences and advice welcome as the Chint 25A (NC1-2510Z) AC3 24V DC coil is about 50 when you add delivery and VAT.
http://chaloncomponents.co.uk/epages/5ce70930-822f-444b-90aa-ca3e0dcdcc0e.sf/sec5b5842e550/?ObjectPath=/Shops/5ce70930-822f-444b-90aa-ca3e0dcdcc0e/Categories/7/Contactors/%22Chint%20NC1%2024V%20DC%20Contactors%22

Finally is it best to isolate both the L and N as I've drawn? I assume I should leave the earth permanently connected to the devices being switched i.e. not run earth through the contactor?

Thanks

routercnc
15-05-2015, 03:01 PM
Hi Dean - PM sent

mitchejc
15-05-2015, 10:08 PM
Your box is looking VERY tidy and I've been watching this part of your build with a keen eye for ideas since I'm +- at the same stage with mine. Well done!

Can't advise you on the suitability of the SSR but I also got a 25A one (not the same make/model as yours) and I was unaware that it would still pass current when off so I exchanged it as faulty only to find out the new one does exactly the same. On mine its enough to light a 220V pilot light dimly an if I recall correctly I measured it at around 12V or 14V when in off position. For what its worth the guy at the shop told me to put a BIG heat sink on it if I plan to run 25amps thru it.

routercnc
16-05-2015, 09:03 AM
Thanks for that Mitchejc,

For info here is where I got to using the SSR (small white square in the middle of the top DIN rail for those who don't use them):
15342

15343

15344

But since these pictures were taken I've removed the SSR because as mentioned above I don't think it works well with the transformer. If it had worked then I didn't plan on using a heat sink because the 25A rating was just to help it survive the unrush current (which is momentarily 100s or 1000s of amps), but then it should settle to a couple of amps (?) for normal running. But if you've got a heat sink then I guess there is no harm in using it anyway.

New plan is to do what I should have done in the first place which is to run 24V DC control instead of 12V (as industry do) which means I can use a 24V DC contactor to switch the transformer and SMPS. The e-stop can then (through the relay) cut power to the drives in an emergency.
The proximity switches are happy on 24V and if I ever upgrade to something like the CS labs unit this also uses 24V. Just waiting for all the new bits to arrive from China.

At the moment I've laid the earth terminal blocks out to act as end stops/cover plates for the main grey terminals because in case you didn't know one end of each JXB4 terminal blocks is open so the last one in the row is 'exposed'. I've got some cover plates on order and when they arrive I can then cluster the earth terminals in the middle to make it as close to a star layout as possible.

Also when the new relays arrive I plan to re-do the diode layout and run it through a terminal block instead of hanging out the back piggy backed onto an cable.

15345

routercnc
16-05-2015, 11:51 PM
Got one of the drivers wired up for power and hooked the linear supply direct to the mains feed (just to check operation)
The driver green led came on and got 72V across the power terminals. Then switched off to see how long it would take to drain the caps. It was dropping just under 0.5V per second so took a couple of minutes to drop to a low level (obviously will be quicker with all three drivers). But strangely it stopped at just under 4V and stayed there. I waited but it did not go any further. In the end I held a 10K resistor across the cap terminal to drain it right down. Why did the voltage stop? Must be something in the drivers that stops drawing current at 4V?
This means there will always be a bit of energy stored in the supply long after it has been turned off. This bothers me a bit so I may add a bleed resistor permanently. Anyone else checked if their power supply drops to zero?

Clive S
17-05-2015, 12:08 AM
You will find in reality in use that with the motors connected it will drop in seconds. I personally don't use a bleed resistor. ..Clive

edit A 10K will do nothing to drain it down even from 70V it will only draw about 7mA

JAZZCNC
17-05-2015, 02:58 AM
Your bothering over nothing. Get it built and working stop freting over shit that doesn't matter. 4v won't even tickle.!!

routercnc
17-05-2015, 08:43 AM
Hi Clive, Jazz,

OK thanks for the info I've stopped worrying now . . .:thumsup:

routercnc
22-05-2015, 11:26 PM
Whilst waiting for the various bits to arrive I've turned my attention to the wiring I'll need for the proximity switches. I've kept this job until last as I knew there were going to be problems.

The prox switches are SN04-N. Brown wire (10-30V) , blue wire (0V), black wire (signal NPN NC).

I rigged one up on the bench (at 12V for now), with a 700ohm resistor between brown and black, then checked the voltage between black and blue. Got 12V or 0V when a metal plate was present or not.
15414

All good, but my BOB is 5V inputs only. So I've thought about the options:

1. Upgrade to 24V logic BOB ! Maybe when funds permit but not now

2. Use a pair of resistors as voltage dividers
I think can work out the ratios OK (top one ~4.5 times the bottom one, giving ~5V tap out in centre?)
But what actual values to use to control the current into the BOB?
What is the acceptable current into the BOB - I've seen a USB board quoted at 7mA . . .
How do I calculate the current my resistor selection will allow into the BOB?
I've got a feeling I need to know the resistor value inside the board . . .

Here is a diagram I created showing one option (adapted from a great post by Irving long time ago):
15410

Here is another option:
15411

But I have a feeling I need to do / know this:
15415


3. Use an opto-coupler module

I bought this out of curiosity (1.32 all in) - just got to wait for it to arrive in a couple of weeks:
15412
15413

http://www.ebay.co.uk/itm/391102497845?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT#ht_5545wt_1109

I asked the supplier about max input voltage and max output voltage but after several days no reply. In the advert they suggest an ideal use is using 3V systems to control 24V systems but I want to go the other way around.
They sell sauce bottles, phones and underwear so I guess they don't make them themselves and probably have no idea!!

Any thoughts on the above options and questions?

Thanks

Graeme
24-05-2015, 11:58 AM
The output of an NPN switch does not have to go to the supply voltage. There is no need for additional opto-couplers or voltage dividers. A NPN output is simply just a switch to 0V.
Depending on the inputs to your BOB you have two simple options. If the input is connected to an opto-coupler then connect the anode to the BOB supply voltage (5V) and connect you proximity switch output to the cathode (may need to add a series resistor if BOB does not have one). If the BOB has a logic type input then simple connect the proximity switch output to the input. You may need to add a resistor between input and BOB supply (5V) if one does not already exist on the BOB.

HankMcSpank
24-05-2015, 01:32 PM
A NPN output is simply just a switch to 0V.

The datasheet is a bit scant... I'd verify that there aren't any pull-up resistors attached to the output of that NPN switch (which would see the supply voltage on the output if the switch is in the open state)....therefore to test, just provide it with its supply voltage & see what voltage is on it output (if any)

Clive S
24-05-2015, 03:47 PM
Some of these proximity switches already have a pull-up resistor inside.
Here is a good explanation of how to calculate it's value.
See page 11 http://cnc4pc.com/Tech_Docs/C50R1_user_manual.pdf in the ones I have it is 10K

..Clive

routercnc
24-05-2015, 08:50 PM
Hi Graeme, HankMcSpank,

OK, that makes a bit more sense now, thank you. I'll check Hank's suggestion first - power it up without the resistor between black and brown and check the voltage on the black. If it is nothing then I have a simple switch and can follow up on your suggestions Graeme. I may need to clarify something with you but lets see what I have first.

If it is 24V then I have a pull-resistor inside the sensor and need to do something else as I know this board won't like 24V into the logic circuits!

I see Clive has posted as well so I'll have a read of his link next . . .

Thank you

HankMcSpank
24-05-2015, 09:46 PM
If there is a voltage on the black, then a simple voltage divider should do....but it'd be useful for you to measure the input resistance of the follow on BOB board input pin (as that will end up being in parallel with your proposed voltage divider)....I'd imagine it'll be very high input resistance on your BOB input.

routercnc
25-05-2015, 04:58 PM
If there is a voltage on the black, then a simple voltage divider should do....but it'd be useful for you to measure the input resistance of the follow on BOB board input pin (as that will end up being in parallel with your proposed voltage divider)....I'd imagine it'll be very high input resistance on your BOB input.

Checked the black wire without resistor and it was 12V (running from 12V supply for now) which means there is a resistor in the sensor and I can't wire it as a simple switch. Used method Clive posted and worked out the value as around 5k ohm

So I can work out the other resistor required to complete the divider except I need to factor in the Bob resistor

Tried to check Bob resistance across pins with multimeter (board was off) and got no reading at all. What is the method to determine this resistance

HankMcSpank
25-05-2015, 05:16 PM
Checked the black wire without resistor and it was 12V (running from 12V supply for now) which means there is a resistor in the sensor and I can't wire it as a simple switch. Used method Clive posted and worked out the value as around 5k ohm

So I can work out the other resistor required to complete the divider except I need to factor in the Bob resistor

Tried to check Bob resistance across pins with multimeter (board was off) and got no reading at all. What is the method to determine this resistance

As mentioned, the BOB input resistance will likely be high ...there's nothing special involved with the measuring method - just check for resistance between the BOB input pin & BOB ground ...powered off is fine. (if you get too high a reading for your meter to detect, then to all intents & purposes the BOB input resistance can be disregarded for the purposes of your 'to be deployed' voltage divider)

What supply voltage do you eventually intend running your sensor with?

routercnc
25-05-2015, 05:28 PM
I had the meter on max setting and still got no reading

Final system will be 24V when PSU arrives - testing on 12V for now

Clive S
25-05-2015, 06:30 PM
OK

If the internal R is 5K then the most current that can flow at 12 V will be 2.4mA. Just to prove this put the meter in series with the black wire to gnd and check (put the meter on to the mA range). I am sure that I used one of these sensors connected to the 5V input of my bob. But don't let the magic smoke out. ..Clive

HankMcSpank
25-05-2015, 06:36 PM
I was just about to suggest trying to establish what value the internal R is (on the sensor)....try connecting a 4.7k resistor between your sensor's black wire & your supply voltage ground ...power up the sensor & measure what voltage you have across the 4.7K resistor (it doesn't have to be a 4.7k resistor ...whatever resistor you have to hand!)

routercnc
30-05-2015, 12:00 AM
Small update. Thanks for all your help on the proximity switches. I think I have a plan on that now but will revisit that later because . . .

24V PSU, 2off 24V relays, and the 20A contactor all arrived in the post today! Big thanks to Dean for some behind the scenes help :wink:.

Managed to get a quick hour in the garage tonight and made some progress:

24V PSU wired in
Contactor to control the linear power supply mostly wired in (need the 24V DC feed to complete)
Shifted all the earth blocks to a common location to make proper star-earth point
Made new earth cables to suit
Added terminal end block clamps to stop them wobbling around
Swapped out one of the 12V relays for the new 24V, but not wired in. Got one more to do.
Added 2 pairs of green adapter brackets (near the VFD) - these will guide the power and signal cable (not added yet). Not really required but they were about 1.30 for 2 on ebay and I just liked the look of them !

Overview:
15436

AC DIN rail coming along:
15437

DC DIN rail getting close (ignore 12V labels it will be 24V):
15438

Questions on the contactor:
T1, T2 are the mains input ?
L1, L2 are the switched output ?
Should I keep the earth permanently connected (i.e. not through T3/L3 of contactor) ?
A1 / A2 24V DC polarity important? I'm guessing not.
There is a 0 / 1 switch in the middle - some sort of tester / over-ride? Can I leave it at 0 ?

JAZZCNC
30-05-2015, 12:57 AM
Questions on the contactor:
T1, T2 are the mains input ?
L1, L2 are the switched output ?
Yes Either or doesn't matter really it's just a switch.


Should I keep the earth permanently connected (i.e. not through T3/L3 of contactor) ?
Yes leave Earth unbroken.


A1 / A2 24V DC polarity important? I'm guessing not.
Yes it matters. A1 is Positive A2 Negative.


There is a 0 / 1 switch in the middle - some sort of tester / over-ride? Can I leave it at 0 ?
It's not a switch it's a Lever. The Contactor can have a Module added onto front and this switches it. Look inside the Box it came in and you'll see what i mean.?

Clive S
30-05-2015, 08:16 AM
routercnc It's a very neat and tidy job you are doing:thumsup:.
.
May I ask where you got the three blue connectors (on the din rail next to the relay) from?.
.
Can I see a blue wire trapped under the din rail where the connectors are!! ..Clive

routercnc
30-05-2015, 09:00 AM
Dean

Thanks for the info. Rushed out into the garage and didn't really see the printing inside the box!

Clive
Thanks for the encouragement!

blue terminal blocks were from ebay
http://m.ebay.co.uk/itm/331547573505?nav=SEARCH
They are really for mains neutrals but work ok like this

Had another look at the picture and it does look like a wire is trapped but it must be a bit of outer sleeving that has dropped into the rail. I was stripping a lot of cables last night.

JAZZCNC
30-05-2015, 10:38 AM
ICan I see a blue wire trapped under the din rail where the connectors are!! ..Clive

Bloody hell Clive you must have eaten some carrots as a Kid. Had to look really hard to see that even after you highlighted.:black_eyed:

Clive S
30-05-2015, 10:59 AM
Bloody hell Clive you must have eaten some carrots as a Kid. Had to look really hard to see that even after you highlighted.:black_eyed:That's what happens when you won't go to bed early.:fatigue:

routercnc
04-06-2015, 08:37 PM
Got the 24V relay and the contactor wired in earlier this week. But when I energise the 24V relay, the contactor switches but the MCB for the linear supply then trips out. Tried it twice and it tripped both times.
.
Wiring diagram re-posted here:
15450
.
Here is a close up picture if it helps:
15451
.
The powering up sequence is:
1. Plug in and switch on at wall - this powers up the 24V PSU
2. Switch master on/off switch which puts the system into e-stop mode and lights up the red LED
3. Press the RESET momentary button which switches off the red LED
4. This energises the 24V master relay (which self-latches)
5. The master relay makes a circuit which runs 24V to the contactor A1/A2
6. The contactor switches on (with a click, and the lever indicator on the front moves to I)
7. This takes the mains power from the 6A type D MCB . . .
8. . . . and feeds it to the linear PSU (which is connected to 3 drives), but the MCB immediately trips
.
If I disconnect the linear PSU then the relay, MCB and contactor operate and power up correctly and stay on so it would seem that the transformer inrush is too high for the MCB?
.
Previously with the linear supply connected to one driver and just through the MCB without the contactor it has switched on (on the one and only time I tried it) without a problem.
.
So, what to try? - What is the reason for most of the current draw ? -
Inrush through the 'shorted' coil until the magnetic field is established ? (750VA 2x24)
Charging up the capacitors (40,000uF) ?
Doing the above and powering up the 3off DQ860MA 80V drivers ?
Or some from each ?
.
I could try switching on and off several times without any drive connected
I could then try disconnecting the AC supply to the rectifier and see if the MCB stays on with just the inrush through the coil - is that OK to do?
If that is OK I could unsolder one of the capacitors to reduce the charging draw.
Up-spec the MCB ?
.
Any ideas? thanks

EDIT:
Bit of reading around and found a document from Allen Bradley, who make lots of good control gear. As I'm protecting the secondary with fuses I can go a bit higher on the primary protection as it is 'just' protecting the wire to the coil and the coil itself. So can probably go to 10A - my logic being:

10A type D should offer around 200A peak for a couple of cycles during switch on
During normal use I'm expecting a couple of amps, so will be OK there
If there is a problem on the primary the 10A MCB should go first as the coil can take 15A and the wall fuse is 13A
Chalon sell the double pole 10A type D for 10.25 all in . . !
Worth a try?

JAZZCNC
04-06-2015, 11:35 PM
EDIT:
Bit of reading around and found a document from Allen Bradley, who make lots of good control gear. As I'm protecting the secondary with fuses I can go a bit higher on the primary protection as it is 'just' protecting the wire to the coil and the coil itself. So can probably go to 10A - my logic being:

10A type D should offer around 200A peak for a couple of cycles during switch on
During normal use I'm expecting a couple of amps, so will be OK there
If there is a problem on the primary the 10A MCB should go first as the coil can take 15A and the wall fuse is 13A
Chalon sell the double pole 10A type D for 10.25 all in . . !
Worth a try?

Exactly What I was going to suggest. I think you'll find that you can even get away with 10A Type C. It's worked for me many times before just to get going so try this if you have one.!

Boyan Silyavski
05-06-2015, 06:37 AM
Now if you make a soft start for the PSU and i will officially say you are the master of enclosures :applouse:


http://www.ebay.co.uk/itm/220V-Class-A-power-supply-amplifier-board-soft-start-delay-temperature-protect-/271644319361?pt=LH_DefaultDomain_3&hash=item3f3f435e81

http://electronics-diy.com/soft-start-for-power-supply.php

routercnc
05-06-2015, 07:21 AM
Thanks Dean
OK will get my order in with Chalon . . .

routercnc
05-06-2015, 07:29 AM
Silyavski
Wow, wouldn't say I'm the master of enclosures - I'm making most of it up as I go along!

Looked at soft start options but I only found home made circuits so thanks for those links. Hope to get away without them but good to know there is a ready made module should I need it

routercnc
09-06-2015, 09:44 PM
Good news !

10A MCB type D arrived today so I swapped out the 6A unit, held my breath, and switched it on. The contactor clicked and the drivers powered up !
.
Could have been lucky (by chanced switched at maximum peak voltage) so tried it again. Same thing, worked fine. Switched off and tried one more time. All fine again. All this was with 3 drivers connected (but no motors yet).
.
Switched off again and checked the decay time on the linear supply and it dropped from 72V at just over 1V per second, and stopped at around 3V.
.
Here is the proof:
15498
.
And here is the new unit (the one on the right):
15499
.
It will be the weekend at the earliest now but hope to mount it on the wall and plug in all the cables etc. to get the basic machine running. It might be the following weekend but hope to machine out the control panel that I was cutting out when it went bang last time.
.
Purely for neatness a few days ago I ordered another DQ860MA 80V stepper driver for the Z axis. When it arrives this means all 4 drivers can run from the single linear supply (I sized it at 750VA to cope), and I can get rid of the 32V SMPS in the top corner. The Z axis stepper is 1.8Nm and only around 1.7mH so I think I need to wire it in series to keep the current down.
.
I also ordered a small 5V SMPS so I don't need to take a feed from the PC molex power supply. Just feels better this way. The top of the control box will then be shuffled around a bit to get a really nice layout and it will allow me to seperate the power and signals even more than current.

JAZZCNC
09-06-2015, 10:44 PM
Coming along nice Barry hopefully no more troubles.!

routercnc
29-06-2015, 09:34 PM
I thought I wait for decent progress before posting again.

Finally mounted it to the wall and wired in the stepper motors. At 72V it jogs around much faster than the previous machine!
15643

The monitor will mount to the door, probably on a small pivoting bracket.

I've swapped out the Z axis stepper driver to another DQ860MA and am running it off the main linear power supply. This meant I could remove the 34V SMPS power supply. I've also added a 5V PSU to run the breakout board (next to the invertor).
15644

I decided after much thought to put both X axis stepper drivers on the same fuse and up the rating to 10A (Y and Z are on 5A each). I was worried that if one fuse blew the gantry would quickly twist and do some damage. This way if one goes they both stop. What has everyone else done?


Recently I managed to machine the front panel and offer it up as a trial. Fits OK but was a pain to machine. It is 3mm aluminium 1050 grade which is very soft. Didn't help that I'd not paid much attention to the 6mm bit I ordered recently and it arrived with 3 flutes. In the end I had to machine it very slowly (120mm/min at 1mm DOC) otherwise it stuck to the cutter.
15645

It should look like this when finished:
15646

Still need to wiring up all the buttons to the panel, add the POKEYs board to the back, wire in the external e-stop, the machine limits and proximity home switches . . . . .

Can't come soon enough to be honest as I managed to jog the machine into the (non-functioning) micro-switches on the X axis and smash them to pieces, plus bend the end stops a bit. Those motors have some power now on 72V !

Another problem is this afternoon the PC just switched off without warning (wasn't cutting just doing a bit of CAM). When I switched it on it said there was a keyboard error and would not start !! More to sort out - but it will have to wait for my next session.

routercnc
05-07-2015, 09:03 PM
The PC switch-off turned out to be overheating. At least that is all I can think of as it had been on all afternoon machining and it was a very hot day. It's working fine now.

15669

I've fitted all of the buttons and started to wire some of it up. Power on/off, e-stop and reset, auxillary to run cooling pump and fan, and spindle start/stop all work. In the process of wiring up the spindle speed through the 10K pot. I'm hoping to get the readout to show the rpm.

Cycle controls and feedrate are not functioning yet. I've still got the POKEYs board to fit and wire up to get those going.

All the e-stop interlock functionality works (e.g. can't start spindle until e-stop is reset, and pressing e-stop stops drivers and spindle), but I've noticed that if the VFD is off at the mains and you switch on the control system, reset the e-stop to get the drivers on, and press the spindle start button on the new control panel, and then switch the VFD on at the mains the spindle starts straight away. It might be possible to add a further interlock for the spindle start/stop if the VFD is not on but as I can't reach the mains socket and the spindle at the same time its not a big concern just something to be aware of.

Clive S
05-07-2015, 10:11 PM
Its coming along nicely when's the party:beer: ..Clive

Neale
05-07-2015, 11:18 PM
The PC switch-off turned out to be overheating. At least that is all I can think of as it had been on all afternoon machining and it was a very hot day. It's working fine now.


When mine started doing this, I found that the cpu heatsink was full of MDF dust...

routercnc
30-12-2015, 09:51 AM
I thought I'd finish off this build thread with the final pictures of the control box, machine, plus my long awaited bed upgrade:

Here is the control box with the door finished and 15" monitor mounted:
16935

I still haven't wired up the POKEYs (cycle start, hold, stop, feedrate) but the rest works.

And the rest of the machine:
16936

The bed was OK but there was often a gap where I wanted to hold something down. It was intended to take a wooden spoil board, and then cutting would happen on top of that. I stripped the old bed out:
16937

Then I machined up a drilling jig to drill each end. There were 4 holes. One pair would take an 8mm clearance and the other pair would take M8 threaded holes. On the next cross member the holes were reversed so that a clearance lined up with a tapped hole etc. The idea was to join each cross member into the back of the previous one and build it up:
16938

16937

Then I added members at the far end. This was to allow cutting pieces on their end and other options. The bed was skimmed to make it level:

16939


Checked it against a known straight edge and it looks pretty good:
16940

Then drilled a matrix of M6 holes for the clamps:
16941

In practice these have not been great and some of the threads have already stripped as the extrusion is only about 4mm thick. I've started upgrading these to M8 which due to the shape of the extrusion will go into a much thicker part.

I've done some machining on the new bed and it is definitely stiffer and gives a better cut than before. Pleased with how it turned out. Will post some pictures of the new bits I've been making in a new thread.

Clive S
30-12-2015, 01:02 PM
Well you now have a very nice neat machine with a suburb looking control box. Looking at the picture of the spindle do you have a cable restraint to stop the cable breaking at the plug as this could be detrimental to the VFD.
.
Big thumbs up. Happy New Year:encouragement:

routercnc
30-12-2015, 03:30 PM
Hi Clive
Thanks for the comments !
:welcoming:
Cable is hard wired (no plug) through the cap onto the motor cables. There is a large cable restraint on top of the end cap which allows a gentle radius on the cable.
I did this after the previous one arced at the plug and blew and killed the VFD.:confusion:
See post #27 for another picture. I'm away from PC but I posted on it in another thread when my VFD blew

My next machine will have the cable running in energy chains rather than hanging in midair but I need a new longer cable to make that happen.

JoeHarris
02-01-2016, 08:58 PM
Nice work looking very smart!

nairepooc
07-08-2016, 05:41 PM
Hi RouterCNC,

Just spent the day going through your build of the electrical cabinet as you made some good points on my build.
Very interesting build and issues that you worked through along the way, hope mine is half as good as yours ;-)
Are the last posts of the wiring diagrams the most up to date or are there others?
Guess I should move onto your MK4 build guessthere could be some more information in those.
ATB,
Ian

routercnc
07-08-2016, 10:18 PM
Hi Ian,

MK4 will run off the same control box so there won't be any updates in that log.

In post #95 in this thread showing the wiring diagram there were some changes made after that:
1. 68V linear supply was actually putting out 72V
2. 30V Switched mode power supply was removed (far right)
3. Z axis driver (MD542) bottom right replaced by another DQM860 driver, and powered by the 72V linear supply
4. 5A fuses going to each X driver replaced by a single 10A fuse shared to both (if fuse blows gantry stops)
5. 6A MCB type D uprated to 10A MCB type D to cope with linear power supply inrush current when switched on
6. 5V power supply cable from PC to BOB was replaced with a dedicated 5V DIN rail PSU (mains driven)
7. A green LED was included in the power on circuit when the main switch was switched on

Very happy with it and works well.

Thanks

nairepooc
08-08-2016, 11:24 AM
Many thanks for the reply.
I have been mulling over the design of mine and plan to incorporate many ideas from your build.
Just placed and order with Chalon for a rotary disconnect switch and two type D MCB's 4A & 10A.
On holidays fo rthe next few weeks so taking viso and some cables, plugs and sockets plus soldring iron with me and relax in the sun while building my wiring looms ;-)
Cheers,
Ian

nairepooc
09-08-2016, 12:21 PM
Hi Ian,

MK4 will run off the same control box so there won't be any updates in that log.

In post #95 in this thread showing the wiring diagram there were some changes made after that:
1. 68V linear supply was actually putting out 72V
2. 30V Switched mode power supply was removed (far right)
3. Z axis driver (MD542) bottom right replaced by another DQM860 driver, and powered by the 72V linear supply
4. 5A fuses going to each X driver replaced by a single 10A fuse shared to both (if fuse blows gantry stops)
5. 6A MCB type D uprated to 10A MCB type D to cope with linear power supply inrush current when switched on
6. 5V power supply cable from PC to BOB was replaced with a dedicated 5V DIN rail PSU (mains driven)
7. A green LED was included in the power on circuit when the main switch was switched on

Very happy with it and works well.

Thanks


Hi RouterCNC
I now have all my bits around me and startng to work through the wiring schematic;
Parts are;
2 off 36V - 400W PSU (for drivers)
1 off 24V 2.5A mini rail mount PSU
1 off 5V - 2A mini rail mount PSU
1 off CP0-10V BOB (cnc4you)
4 off CW5045 (cnc4you)
1 off UC300 (cnc4you)
2 off E-Stops (2 pos NC)
4 off 24V 10A DPDT rail mount relays
1 off 4A type D MCB rail mount
1 off 10A type D MCB rail mount
1 off Rotary panel disconnect
1 off 10A EMI filter (cnc4you)
1 off Green reset (NO) panel push button
2 off 24V fans (blown air into cabinet)
1 off Green panel mount led (5Vdc - live)
1 off Yellow panel mount led (24Vdc - live)
2 off White panel mount leds (36Vdc - live)

DIN rail mounting and red, black, yellow and fused connectors.

Oh and I have been given a PILZ PNOZ 16S safety unit, just not too sure how to incorporate this.

I did notice that you have an Allen Bradley unit, would this be of use to me or do I have enough above?

routercnc
09-08-2016, 10:08 PM
Hi nairepooc,

It would be best to start a new thread on your build. Also, I wouldn't consider myself an electrical expert, I got through my build after many wrong turns and used the advice of fellow forum members.

I haven't use the Pilz myself, but it is purpose built and used commercially and is well known. Instead I was happy with a standard relay to run all the 24V signal control hooked up to the e-stop circuit and wiring it up manually to create the latch circuit. If I remember your schematic that is what you had done so a Pilz unit is not critical.

This relay in turn drives the 'Allen Bradley' unit. This is a contactor and is a purpose built relay (with lots of features as m_c posted on recently). It uses 24V DC to switch 240V AC. When the control box is turned on you have to press the reset button to latch the 24V circuit. This then sends 24V DC to the contactor signal terminals, which in turn switch the mains (L) and (N) feed to the linear power supply. This in turn powers all the drivers at about 70V DC.

As has been pointed out by others, you could use a normal relay instead to switch the mains so long as it can take the current. I have a linear PSU with high in-rush current so didn't want to go that route. Maybe SMPS is lower in-rush and would be OK - but I'm not an expert.

I had to size my MCBs with some trial and error, and forum advice, to meet my particular needs. You will have to decide if 4A and 10A are what you need in your case, or ask for further advice on those.

Tom J
03-01-2017, 10:25 PM
Bloody hell Clive you must have eaten some carrots as a Kid. Had to look really hard to see that even after you highlighted.:black_eyed:

20209

I start using spec glasses at 40, try the same Dean:)

Clive S
03-01-2017, 10:43 PM
20209

I start using spec glasses at 40, try the same Dean:)

Well done Tom digging up the past and upsetting Dean I thought he used a bloody great magnifying glass:glee:

Tom J
03-01-2017, 10:46 PM
Well done Tom digging up the past and upsetting Dean I thought he used a bloody great magnifying glass:glee:

Only did as I realized that he is on better mood:smiley_simmons:

JAZZCNC
04-01-2017, 12:01 AM
20209

I start using spec glasses at 40, try the same Dean:)

Bloody hell You need to get out more if nothing better to do than go back that far to get your Kicks.!! . . . . But I've got pair in every room and vehicle so now I'm sorted.:thumsup: