It's begun....

[Washout]

Just a quick pic showing rails going on:

[Washout]

Another pic showing the beginnings of the Z axis.

I must be doing at least something right here as it moves nice and freely on its Y axis rails (as my crushed finger will attest to when I tilted it to put it back on the bed ;-) ).

Also I guess I should relate some areas of "interest" (read frustration) getting this far:

Firstly I had a problem with the profile from metallin having a slight ridge along the centre "flat area" on the 60x60 profile. This combined with Chai using hex machine head screws meant the rails would not sit flat to the profile bars but instead rocked side to side. This was easily fixed with replacment button head screws, which are lower profile and therefore the ridge in the profile can sit inside the rail supports and they can lie flat. Mine were very tight, but didn't have the stripped threads I see in another build log....probably air tools or something used to screw them in with too much torque.

Secondly screwing the extrusion together can be a pain, but I found that using a couple of turns on each screw using a similar pattern familiar to anyone who has torqued a cylinder head down seems to work well and almost pulls the extrusion into alignment itself (provided its cut at a nice right angle, which I'm using a TCT bosch blade in a chop saw for).

Thirdly I highly recommend a spiral flute tap (I think that's the correct name) for tapping the aluminium. The alloy for the extrusions seems to be stickier than most and was clogging up my normal taps after only a few turns. Even backing out to break the "chip" after every 1/4 or 1/2 turn didn't seem to help on my normal taps. IIRC I got the spiral flute tap from Arc Euro trade (is that John S's company?) - highly recommended and I'll be ordering more goodies from there in the future.

Of course there is much more to do, but it is nice to have a moving part operating correctly on the machine.

My ali plate also arrived today from Aluminium Warehouse (thanks for the link Jonathan), so I can get on with making the mounting plates to fix the X Axis bearing blocks to the gantry.

I am also having to do an on the fly redesign of the z axis, as the 120mm extrusion is not going to be wide enough for the two supported rails and ballscrew mount etc. Luckily I ordered a 1000x500x15mm ali plate so I have at least got plenty of material to make a wide version from.

More as I progress......

Cheers


Chris

[Washout]

Hi All,

Build has been on a bit of a pause since my last post, partially due to waiting for a new circular saw (read more powerful and able to take my Bosch 210mm metal cutting blade), which I also needed for some other wood projects and also due to finally selling my house, which means I will (fingers crossed) be moving to premises with a nice 30x15 foot workshop :-)

Anyway here's a quick couple of pics of the wiring work in the control box (re-purposed rack mount servre case) progressing and its now pretty much complete, with the remaining XLR sockets wired to the BoB, which will be used for limit switches and spindle relay (need to find out how the latter is wired i.e. at the VFD directly if it has one built in or whether I need to grab a seperate unit). The second pic shows the mains on/off switch, which was a nice fit into a 3.5inch drive bay blanking plate.

Stuff I need to do in the control box are decide if I need the short CY cables shielding earthed (probably not) and work out where the parallel lead will go.

Which also leads me to a few questions:

1. What kind of parallel lead will I need, as there are data transfer and printer types and IIRC 1 is 25 pin straight through and the other has a pin 1/2 swap like a nul modem (been a while since I've used a parallel lead on anything).

2. Also has anyone run a 3metre parallel lead and is this likely to be an issue?

3. Finally has anyone used this unit? Zapp Automation Ltd - Stepper motors & Stepper Motor Drivers - Servo motors and Servo Motor Drivers - Ballscrews & linear motion products. : PLCM-E3 CNC Controller (For use with Mach3) [PLCM-E3] - £150.00

From reading up on it, it doesn't seem to do more than provide conversion from ethernet/USB to an existing Parallel port BoB (or BoBs), but using my structured cabling to connect the PC to the controller box is appealing.

Tomorrow I will likely attempt to chop my ali plate for the Z axis and the spacers to mount the gantry to the X axis bearing units.....will report back after that...

Later


Chris

[Washout]

Ooops nearly forgot.

As I tend to cover all soldered connections with heatshrink I have kept a spreadsheet of conections and wire colours etc, so that if I am troubleshooting or adding new wiring I can work out what goes where and its function.

Might be of use to somebody, so attached.

Cheers


Chris

[m.marino]

You might want to look at www.ascmetals.com and remember that Aluminium can have both a crown and warp to the sheet. This means that unless you are buying engineering grade that you will most likely have to face the metal or have it faced to bring the surfaces into true parallel. Depending on how large the section of plate you are using this might have no effect, on the other hand the wider and long a plate is that has not been brought to tolerances the more likely the piece will have warp or crowning and that means surfacing/facing needed to be done to bring it into tolerances.

Just a few points that you might want to consider when looking at buying as the cost in material does have a bit of a reason behind it.

Michael

[Washout]

Thanks Michael,

Link added to my list of suppliers.

The ali plate I have seems to be pretty accurate over the size I'm cutting it to, but I'm expecting some shimming being necessary, as my cutting of extrusion is likely not to the same tolerance. Hopefully I can get the machine true to itself to a certain degree and then work on replacement parts machined to better tolerances than the current tools I have been making it with, or of course issue some RFQs here for bits...

Cheers


Chris

[Washout]

A quick update, as I got some time to work on the machine tonight, but no pics (will post some tomorrow):

I have my first ballscrew mounted, as I figured before I attach the Z-mounting plate the Y Axis needed to be finished. Used a Bosch 17mm bi-metal hole cutter to bore the holes in the gantry sides for the ballscrew and I find these tend to cut ~1mm over size (possibly due to my bench drill being a little wobbly). This is fine however as I need a little clearance to allow for alignment adjustment and have ~1mm rather than the intended 0.5mm.

The floating end is attached using an FK bearing block and circlip and the fixed is also a larger FK type which goes in the stepper motor mount and that is bolted to the gantry side also.

I have come across one of those annoying gotchas where the supplied ballnut mount protrudes ~1mm too far outside the gantry, so I need to work out whether I can "pocket" the ali plate for the z axis by 1mm using the tools I have. I'm thinking of very gently/slowly milling the pocket using my bench drill and an 8mm TC End Mill with the z axis plate clamped to my small cross slide table (normally only used for drilling holes in a straight line) - not sure I should mention a foolish move like this here, but it's a problem that needs solving (I have also toyed with using a low speed on my hand wood router, but I don't trust myself with that method.....).

Hopefully tomorrow I will also get try out the new circular saw on the ali plate (didn't finish work till late and the neighbours would probably not appreciate the tortured machining noises;-) ).

I must also try to resist connecting up the Y Axis just to get something moving under its own steam.....

[Washout]

Afternoon gents (and ladies),

Not posted for a little while but I have not been idle ;-)

Here are a few pics of latest progress and despite a few "rough" bits (z axis plates and spindle mounts), I am finally approaching the end of the mechanical side of things.

I do a have some deflection in the gantry, which is due to my crude mounting solution, but have an RFQ out to help resolve this and will soon order a second ballscrew plus pulley/belt to make sure both sides get equal x axis driving force.

In the meantime, I am now working on the cable runs for the steppers and then the water cooling system and VFD/spindle wiring.

Good news is I have the rest of the year off from work, so I'm hoping I can get at least some light material cutting underway before Christmas.

Lastly before finishing I had better relate some frustrations:

1. I had underestimated the weight of the gantry once all the "stuff" is on it and care is needed when assembling the z axis, as its easy to drop the spindle/mounts etc and if your fingers are in there pain can result - propping things up when securing bolts etc is a must

2. Constructing the z axis is a pain the first time you do it - everything had to go on in order to avoid not being able to get tools onto bolts/nuts etc.

3. Like a berk I assembled the gantry reversed as you can see in one pic, but luckily I needed to almost completley disassemble the gantry to get the y axis ballscrew mounting block in, so put it back the right way.

4. to align the x axis ballscrew I torqued down the fixed end (stepper motor end) then ran the gantry by hand to the far end and tied down the ballscrew and floating end bearing. Hopefully that is the correct method, but it turns and moves easily by hand (I'm assuming turning a stepper by hand is OK).

5. I had a job getting the rails into the bearing blocks on the z axis and actually stripped a bunch of ball bearings out of one of the block, so had to get some replacements, but they are relatively inexpensive and I've sorted out a method which involves only bolting one end of the rails to the front plate, which gives some play to allow for alignment. I then put the remaining bolts onto the rails once they are located in their bearing blocks - not a hard job just needs doing with the front plate in the right place, so I can get access from the rear.

Oh I should (fingers crossed) be moving house soon and I'm really looking forward to the new workshop :-)

Hopefully my next update will not be too far away.

Later



Chris

[Washout]

Quick update and some questions someone maybe able to help with.

I have thrown an e-chain on for the x axis movement and wired up the 3 steppers with cables going back to my control box (shield connected at the control box end to my earth point and not at the machine end).

I figured I would get the stepper motors working first before moving to the spindle and VFD and to prepare for the first control box power up I have done the following:

- Manually moved the spindle to the centre of x, y and z travel so that if for some reason the machine decides to shoot to the extremes of my travel I have time to hit the estop.
- Loaded Mach3 and connected the PC I'm running that on to the ZP5A-INT controller board/BoB but not in the control box so I can set up the software according to this pdf manual without risk of the machine moving in an undesired fashion: http://www.zappautomation.co.uk/down...d%20manual.pdf

After running through that manual for setup I have loaded the Roadrunner.tap and run the GCode - the LEDs for the axis on the board are flickering nicely in sync with the movement on the Mach3 3D display, which is encouraging.

All good so far, but here comes the questions:

Having wired my steppers and drivers in bi-polar parallel mode (wiring diagram: http://www.zappautomation.co.uk/down...%20%281%29.pdf) I am now stuck with what dip switch settings to use on the drivers (PM752's - http://www.zappautomation.co.uk/down...vers/PM752.pdf) with the following Steppers: SY60STH88-3008B (Data sheet: http://www.zappautomation.co.uk/down...H86-3008BF.pdf)

My first guess is the following in order from SW1 to 8: OFF, ON, OFF, OFF, ON, ON, ON, ON which should translate to Peak Current 4.09A, RMS Current 3.32A, Standstill=Half Current, Microstep=4, Steps/rev=400 - I have no idea if this is correct although one of the manuals mentions setting the Amp rating to the closest for the motor and 4.09 seems to fit that bill.

Any help would be gratefully received before I wire the BoB back in and throw the switch just to see what happens :-)

Oh if it helps I have 1605 ballscrews on all axis.

Cheers


Chris

[Jonathan]

My first guess is the following in order from SW1 to 8: OFF, ON, OFF, OFF, ON, ON, ON, ON which should translate to Peak Current 4.09A, RMS Current 3.32A, Standstill=Half Current, Microstep=4, Steps/rev=400 - I have no idea if this is correct although one of the manuals mentions setting the Amp rating to the closest for the motor and 4.09 seems to fit that bill.

That is correct. Also depending on the feedrate you get and the kernel frequency your computer will support you may be able to use 800 or 1600 step/rev which will help the machine run more smoothly.