MDF and alu sandwich router

[Tom]

Well, I've decided to start building the router I pictured over at CNCZone.

Shall i build this router? (http://www.cnczone.com/forums/showthread.php?t=80112)

I'll do the build log here at CNCUK because there seem to be several people nearby... :) Thanks for your encouragement so far.

The build will be in 4 stages, partly to help my planning, and partly to spread the spending evenly (ouch!)

Stage 1: Build basic MDF structure, bearing carriages, and get it all moving. No alu at this stage. If the machine's looking sloppy or flawed I may call it all off at this point (I'll only be about £120 down).
Stage 2: Fit motion components to structure (bearings, leadscrews, motors, etc)
Stage 3: Wire up the electronics and get the machine moving.
Stage 4: Fit router (kress), make test cuts, then re-cut the final MDF and aluminium skin components.
Stage 5+ Do useful work. I'm not planning for this to be purely a toy - it will be earning its build cost back. Might also earn itself some upgrades in the distant future.

Attached pics: (how do I get them to appear in the thread?)
Initial sketch
Pile of MDF, with the base layed out dry
Base glued and screwed, with gantry MDF cut
Top surface of base, showing screwholes, and holes for later workholding (M8)

That's enough for now. Next step is to put the lower skin on the base (hope it doesn't fall through the floor), and order the bright steel bar....

Anyway, I have a prior history of almost finished projects. I hope putting myself under some pressure by posting will be useful! :eek:
Feel free to give me grief for no progress!:biggrin:

Cheers,
Tom

PS. Just tried to upload all the pics, but max size is 800x600. I don't really want to re-size everything manually - any way around this? CNCZone took the biggest size no problems.
Sorry to keep you in (very mild) suspense chaps - it's late now...

[Lee Roberts]

Humm, i thout i'd covered everyone.

ok try uploading them now.

[Tom]

Uploads are working today (thanks Lee)

Attached pics:
Initial sketch
Pile of MDF, with the base layed out dry
Base glued and screwed, with gantry MDF cut
Top surface of base, showing screwholes, and holes for later workholding (M8)


The only changes since I made the initial sketchup sketch is I've built the base from 25mm MDF, instead of 12mm. I saw the prices at Great Barr Sawmill (http://www.greatbarrsawmills.co.uk) and decided it was worth the extra £10. GBS also do a great service of ripping the sheet up to your dimensions free of charge (within reason) using a professional table saw. I got them to cut all the base pieces out, and I've cut all the gantry pieces myself. Fantastic service, and well worth the 1.5hr round trip.

Steel's all ordered tonight for collection tomorrow from Eggleston Bros (http://www.egglestonbros.co.uk), so I might have a weekend of pillar drilling and bit sharpening ahead of me....
Bearings are also on the way (ordered from ebay), so all the stage 1 ordering is done.

Just got to build it now ,,,,,,:eek:

[Smiler]

Hi Tom,

Looking good mate and welcome to the forum.

Regards, Jeff.:beer:

[Lee Roberts]

Cant wait to see the build unfold Tom, who did you get the bearings from on ebay ?

[Tom]

who did you get the bearings from on ebay ?

I got them from this chap. (http://myworld.ebay.co.uk/cvrltd/) Is that you? :) They've not arrived yet, but i'm expecting them to be low-rent.

Some progress tonight - I got the M8 nuts fitted to the inside of the router base. I thought it would be a 30minute job....

Ho hum. 74 nuts and 2.5 hours later I've just finished!

Pics:
I counterbored the 8mm holes with a 12.5mm bit on the underside of the base.
Then pulled a nut into each counterbore using a screw. M8 nuts are ~14.5mm across the diagonal, so they're staying put.
Finished. Just need to put the underside skin on now.

[Tom]

My bearings arrived today. At 27p each I can't say I was surprised when they weren't packed in individual Nachi Bearing (http://www.nachi-fujikoshi.co.jp/eng/jik/tokutei/indexkos.html) boxes, but I was pleasantly surprised by the quality. They're smooth and were bulk packed very cleanly with no grit in sight. They'll definitely do the job.....! :-)

Also collected my steel tonight. Very heavy. And about 1m longer than a VW polo.


Hows your arms?

Arms are recovering thanks... :smile: They need to - they've got to hacksaw this steel up into at least 29 different pieces before I can spend any more money! :eek:

Pics:
27p "don't bet your life on 'em" bearings
Worra lorra steel (quite nice sharp corners - never worked with bright flats before)

[Tom]

Hey Kip,

Yeah I'd love a bandsaw!
I made the X carriages today (probably put pics up tomorrow). Funnily enough the hacksawing (5 cuts) took half an hour, and the pillar drilling took most of the rest of the day! (44 holes centred, 4mm pilot, then 8mm final size) The end result looks tidy, but blimey that's a lot of holes.

Some good came of it though - I calculated the proper RPMs for drilling steel at different bit diameters. It turns out I've been drilling steel far too slowly for the last couple of years! It's like butter at the right speed (with some cutting fluid)... :cool:

I've attached the spreadsheet I made just in case anyone finds it useful. The steel figures seem about right, but not tested alu or SS yet.

[Tom]

Lots of hacksawing and hole drilling this weekend.

Pics:
1) Finished X carriages
2) X carriages mounted to Y gantry
3) Detail of rear of gantry with emergency dowels - without these the 12mm MDF was splitting, and the gantry had almost no strength.
4) The gantry wedged under the table to see what it looks like. Z plate is propped up to get an idea too.

The next step is to get the X rails drilled and mounted to the underside of the table. Can't wait to get the gantry rolling... I've tested the carriages on the rails already and found them smooth rolling, but sensitive to quite small pieces of debris on the rails. Hopefully having them mostly tucked out of harms way will keep them fairly clean - if not I'll add some oiled felt wipers later.

I'm quite enjoying this! Hopefully there'll be a 2nd working router in Derby soon,,,,,

[Tom]

Yes, they are quite chunky - nearly 3kg each.

MDF is great to work with apart from the dust. I might buy water resistant MDF next time I buy a sheet - the extra resin might mean its a bit less dusty. One other downside of MDF is the smell - I can't wait to paint this thing - my house smells like B&Q!!!

[Tom]

OK, a bit more progress this week... And the result is a rolling X axis!! wooo hoooo!!

My Y gantry was ready to go, so this week I drilled the X rails (8mm dia), clamped them to the router bed and adjusted to get things roughly symmetrical. When happy, I put 8mm holes through the router bed itself.

Next I removed the rails and opened the holes out to 12mm dia - this is part of my 'cunning plan' to allow things to be set up just right when it comes to final assembly. The oversize holes allow up to 2mm adjustment in each direction (there's a similar arrangement in the carriages, but only 1mm each way).

I also had to do a bit of 'fine tuning' with a newly ordered 16mm dia bit to counterbore for the hex screwheads. I thought modelling the fasteners in sketchup would be going a bit too far - I was wrong!!

Getting it all fitted up and adjusted was a little fiddly, but not as bad as it could have been! :clap:

And it rolls fairly smoothly.... A bit of a relief! :biggrin:


http://www.youtube.com/watch?v=7o2Nd1u4tDQ

Pics:
1) Fitting the first X rail
2) Counterbore for screwhead clearance (oops)
3) Looking along one of the rails
4) The whole machine, with Y rails drilled ready to do the whole thing all over again on another 2 axes :eek:

Right, I'm off camping for the weekend,
Tom

[michael]

Builds lookin good mate,

As for your spindle, I'm now qualified to say get a Kress!, I know you were going to come over the other week to here my Trend T3, Since then the bearings gave way and I'm now the proud owner of a Kress 1050 thanks to a little trade with Steve.Hilton:yahoo:

It makes half the noise and has twice the power, Soon as I picked it up I knew it was a qaulity item (pretty heavy though).

Michael.

[michael]

I had one to wire into another machine...I didn't believe it was spinning at 30.000RPM it was so quiet!...applied tacho....30.100RPM Are you considering water-cooling the router mounting?

I did notice the 43mm collar felt rather hot after a short period of time, Is it the bearings that are getting so hot or just the motor it self.

Water cooling the mounting? Sounds interesting have you any examples on how this can be acheived:question:

Michael.

[John S]

Well you could pi..............no we won't go down that route :yahoo:

.

[michael]

So that wasn't suds you were using on your Bridgeport then John?

[michael]

Well you could live dangerously like John suggests :naughty: If your pee is pure you won't be electrocuted!....take a chance :D

I was thinking just a piece of square bar bolted to the mounting with a hole down the centre and pass water through...voilà kiss principle cooler :idea: I have one drawn up in cad somewhere that got a little fancy.

I'm not sure of the internals of the Kress ie whether it's like a lot of routers and has the bearings mounted in rubber cups or if they're in metal for heat transfer....Bearings get hot and the comm takes a pounding (I have a router that I ran for 5 minutes and the comm is messed up...cheap crap) Way too much plastic in use on electric tools these days!

Would like to see a pic if you find your cad drawing:wave:

[John S]

Possible to simplify a design I don't split my brackets.

http://www.stevenson-engineers.co.uk/files/kress1.jpg

I drill the side hole first and put a bolt and nut thru and tighten it up, then bore the 43mm hole.
Lastly I cut the head off the bolt so the stud with cutaway can move and clamp.
Just like a tailstock barrel clamp.

Saves a slitting or sawing operation, did I mention I was idle ?

Not noticed mine getting hot but it's only the 800w model, never run more that 6mm cutters so couldn't see the reason to go bigger

[michael]

Nice clamp John, not seen any made this way before.

Michael.

[John S]

Yes it's a .cad format that will only open if someone has got Bobcad.
took the liberty of getting a jpg from it.

I presume the small circles are for a top mounting plate ?

http://www.stevenson-engineers.co.uk/files/Kip%27s%20mount.jpg

.

[michael]

My doodle.... Drawn in Bobcad so not sure if it'll open correctly in anything else...A cotter pin John....lazy bugger :D


Can u do DXF? or if its 3D step,iges etc sorry but none of my cad software will open it!

Michael Duffin.

[John S]

Aahh, all becomes clear.

http://www.stevenson-engineers.co.uk/files/Kip%27s%20mount%20solid.jpg

.

[John S]

Better get some air-con...I'm melting.........

Poke the bat with a sharp stick.................

.

[Tom]

Here's me cobbling a wooden hulk of a router together, and everyone's discussing the finer points of water-cooled spindle mounts! lol
CNC machined of course - this must be what torture is like (only metal-removal tools in this build so far are so far are a hacksaw, and hand/pillar drills)!! :rolleyes:

I suppose I can only promise to be creative with this machine when it's finished to make up for this!

While we're talking about water cooling splindle mounts - I think a combination of John's cotter pin design, and Kip's water path with coverplate would be best. I recon fewer risks of water leaks caused by flexing to tighten onto the router.

Thanks for the complement Michael - I think I'm going with a Kress. Only choice is 800 or 1050 - seem to be the same (expensive) price on ebay. Anyone know of any 2nd hand ones going?

OK, a bit of progress. The Y and Z mechanics are finished now. A bit of adjustment will be needed to get the Z exactly perpendicular to the table, but that can wait till leadscrew time. I'm pleased with the way it's turned out - heavy for sure, but no sign of any flexing.

Pics:
1) Distance shot (can't see the rough edges from back here!)
2) Close up - (ah yes, there are the rough edges)

[John S]

Thanks for the complement Michael - I think I'm going with a Kress. Only choice is 800 or 1050 - seem to be the same (expensive) price on ebay. Anyone know of any 2nd hand ones going?



Got two brand new ones here but the old single speed series, could be made to run variable with a light dimmer switch, not sure what model, I think about 750 w
Need to check tomorrow as it's dark here and that workshop is bloody haunted...........

.

[John S]

Well managed to get a few minutes today free from upsetting customers long enough to do a few water cooled Kress mountings.

I suppose you could call these Waterkress mountings :naughty:

http://www.stevenson-engineers.co.uk/files/waterkress.jpg

One piece construction with the water going around about 70% of the circle, 6mm push in piping.

Couple more at the back just want scotchbriting as this was the last bit of 25mm thick bar I had and it was a *bit* shop soiled.

.

[John S]

No cross drilling, it's all milled out internally with a 8m cutter down the sides to form 20 mm wide slots and a 14mm cutter at the back.

No idea on pump, just made the mountings to order.

.

[John S]

Close but we use bats. :nope:

.

[Tom]

Ladies and gents,

Today I can happily announce the arrival of my leadscrew. :-)
Which means that very shortly the machine build can re-start. The only components I don't have yet are the power supply (50V and 12A max, probably play it safe with 45V and 8A should be fine), and the router itself....

EMC2 is running and recognising estops and limit switches, so all in all I can't wait to get stuck back in. :yahoo:

But first I've got to go to Poland...
Back soon I hope...

[John S]

But first I've got to go to Poland...
Back soon I hope...

Bring us a chuck back............

.

[Tom]

Lots of Poles, stunningly good looking women, and factories in Poland. Sadly I was involved exclusively with the latter...:nope:

Didn't know Poland was famous for chucks either - let me know some manufacturers and I'll do some research (it seems I may have wasted 12kg of my 20kg baggage allowance :naughty:).

Kip cheers for the power supply link. Even including postage that'd come in at the same price as the toroidal transformer alone! (nevermind the cap(s), rectifier, and faff) Cheers! :beer:

My finger is hovering over the buy it now button, but I'm a little worried about the voltage. My drivers have an absolute max of 50V, so I was going to play it safe with 45V or so. Those power supplies are trimmable from 50.5V to 56.5V according to the datasheet.

What's the best way to drop 5V or so at 10A? Shall I order something like a 50W power resistor?
http://docs-europe.electrocomponents.com/webdocs/0031/0900766b8003123a.pdf

[Tom]

What drivers do you have?
I bought the "standard" 18-50V, 4.2A max drivers that everyone seems to be selling (black cases, green terminal blocks). Got mine from Arc Euro Trade at a very fair price with free shipping. I recon they compare OK with geckos.


if no good I'll buy em off you :D
Cheers for the offer, but you should buy your own! :whistle: I'm confident they'll be good! :biggrin:
Seriously though, have you got your 'lectrics sorted yet, or is that the next step?

I'm going to order one of those power supplies and a resistor... Cheers again for the link....

[irving2008]

Nice powersupplies and i've ordered two (can never have too many supplies hanging around!)

Note though you may need to use a reverse energy dump circuit with this supply as it has an over-volts latch off function if the output voltage exceeds 60v. With a large stepper under load the reverse EMF could cause the over-volt trip to shut the supply down (sort of like a self-inflicted e-stop)

It shouldnt be hard to tweak it to go below 50v. When I get it I'll have a look, also will advise on best way to replace the output connector with something more cost effective as the DIN41612H connectors are £10+ each without the shells. The connector on the supply is a male, so it may be possible to use female push-fit spade connectors directly on the terminal pins.

[Tom]

shouldnt be hard to tweak it to go below 50v. When I get it I'll have a look, also will advise on best way to replace the output connector with something more cost effective as the DIN41612H connectors are £10+ each without the shells. The connector on the supply is a male, so it may be possible to use female push-fit spade connectors directly on the terminal pins.

Thanks Irving,

I was hoping spade connectors would fit too, otherwise I was just planning to solder directly to the pins (not pretty), or open the box and find another way.

I'd read about energy dumps for back EMF during deceleration, but didn't think that would affect steppers so badly. Anyway, it would be great if you could let me know about voltage adjustment when you get the supplies..... :biggrin:

[Tom]

OK then,

The summer has been had, the long evenings have long gone, and it's time to get back to the CNC router build.

Over the last couple of weeks I've been getting things back in shape (mainly remembering where I'd put everything). I got the electrical panel built during a day off work a fortnight ago - once I saw the motors singing there's no way I'm stopping!

Here's a video of the YZ gantry moving.
Y travel is 480mm, Z travel is 100mm in this video but it will go further.
These are G00 moves and the speed seems quite good (but it may be losing steps - need to check with some dial gauge tests when its on the x table).
I'll post the current EMC2 accelerations and velocities next time I'm near that computer.


http://www.youtube.com/watch?v=q6VKNQsS78A

Next jobs:
Mounting the X axis leadscrew and nut.
Then limit switches and a bodged up router mount.
Then (quickly before it all falls apart) I'll need to mill an MDF router mount, followed by decent motor mounts (they're pretty heath robinson at the mo).
Finally, make a few xmas presents on it... :) (time is v short)

Photos:
Pic of the front
Bodged temporary motor mounts
Rear of the Z carriage

[jonm]

hi tom
could you tell what breakout board you used with the euro arc trader drivers, i looked at these are they ok


thanks

[Tom]

Hi Jon,

I'm very happy with the drivers. I've not worked them hard yet, but they have a decent feel of quality. They're on offer at Arc Euro at the mo - For £39 I can't find a complaint...

I bought a readymade breakoutboard from DIYCNC (PCPPS-2). This is the simple board which is not opto-isolated. As far as I remember the inputs to the drivers are opto-isolated so I decided there was no need to double-up. Also I have a scrapper of a PC running EMC2, and I'm not doing anything commercial, so the consequence of a fried motherboard is not too serious (also unlikely).

I got the one with a charge pump to improve safety, and it also has a voltage regulator to provide 5V for the limit switches, which is handy...

[jonm]

hi tom
thanks for reply i am using the system 3+ board from diycnc
with 3nm steppers board limit is 30v , i think i could do with more voltage on these steppers , its always good to hear positive feedback before you buy, £39 each aint bad may give em a try

thanks

[Tom]

The shakedown runs of this router are finished, and I'm growing in confidence with it.... Purely for posterity here is a before screengrab from sketchup, and an actual photo of the thing for real! (complete with deadly MDF dust)

There are a couple of weaknesses with it so far. Some are easy to build out with some re-cut panels, which I'm in the process of doing. Others are slightly more fundamental (but happily, not too serious).

Improvements to make:
1) The gantry is not sufficiently strong along the Y direction. Looking at it now it's obvious! But there are no diagonals, and I'm re-cutting these before even attempting alu. If you remember, this is supposed to be an alu sandwich router, but it's going to need gantry #2 before I can cut the alu for gantry #3...

2) The X leadscrew is not perfectly straight (well actually, bent!), and combined with the poorly braced gantry leads to wavy sides (pitch of 4mm!) on the x edges of parts I cut. Hopefully the braced gantry will fix this. If not, a new screw....

3) Some poorly placed drill-holes during the initial build means that at the moment the Z axis sits a couple of degrees away from vertical. The collet end of the router hands back under the gantry. Again, some re-cut panels (with computer aligned holes, not pencil aligned ones) will solve this.

4) The final, slightly more thorny problem is that the Y rail support twists slightly (tucks under) in the x direction, when the router is at full Z travel down. The problem is worst in the centre of the Y travel. A fix to this would involve spacing the Y rails further apart, and re-drilling the Z carriage to accept new skate bearing positions. It's not impossible, but I will try alu skinning first, possibly followed by replacing that piece of MDF with a chunk of solid alu if that doesn't work (it's only 100mm x 700mm).

Current max axis speeds are (so I don't forget):
X 40mm/s, accel 80mm/s/s
Y 100mm/s, accel 110mm/s/s
Z 30mm/s, accel 60mm/s/s

X and Z are conservative, put there to stop the machine shaking itself to bits with a wobbly gantry and bent screw. I hope to increase these as the improvements are added...

A happy speed I've found for cutting MDF so far is 1800mm/min, with a 6mm 2flute mill, and 4mm of cut on each pass. This is definitely limited by the current rigidity of the machine, but onwards and upwards... Rooolll on the improvements.... :smile:

[Tom]

Here's the first really pleasurable job i've done on it... This was fun, a small oak box as an xmas present...

Pics:
1) ProgeCad
2) CamBam
3) EMC2
4&5) The finished article (too many straight lines though :wink:)

(oh by the way, there was some belt sanding involved - unfortunately didn't come off the machine looking like that! :)

[Tom]

Happy New Year!

I've spent part of this holiday getting my router into better condition. I'm surprised at how much time it takes to go from a machine that moves, to one you can walk away from during a job. I still have to pounce on the E-stop too often!

There are some photos of the latest changes.
Major one is that the new gantry is now fitted. This is now 18mm MDF (was 12mm), and it has bracing round the corners which improves the rigidity massively! It's fixed problems 1 to 3 in my earlier post. I think the aluminium skins are still worth adding, but that will be in a few more months when it's earned some money!

A smaller change is that i've added flexi conduit to control the cables. This has tidied it up immensely, and is a major step towards the day when I can sit in another room with a cuppa while the machine's running! lol Unfortunately it's two steps forwards, one step back - it doesn't bl***y work any more because of electrical noise issues which keep tripping the limit inputs during a run. :thumbdown:

I shouldn't be surprised - the motor and signal cables are both unscreened, and they're now running in the same conduit in some places. There's some lovely screened motor cable on it's way to me now. For the screened signal cable I'm going to butcher a network cable, which is an idea I've pinched from Robin's Mill Build Log (http://www.mycncuk.com/forums/showthread.php?651-Warco-Major-CNC-build-log&p=9999&viewfull=1#post9999)

Lesson learned - make it bombproof from day one!

[Tom]

Mainly for my benefit - a few EMC2 file backups (v2.3.4).
If they're not useful to you they will be to me if my PC every fries itself!!! :eek: (Thanks for the diskspace Lee! :beer:)
If anyone uses these just be careful - I'm learning so there could be some mistakes in here I haven't found yet...

Change summary:
Custom HAL File - startup of classicladder for touchprobe. Startup of chargepump.
Custom PostGUI HAL File - connects AXIS PyVCP buttons (jog, touchprobe, and various easy homing and co-ord change buttons)
Main HAL File - not sure if there any changes here - maybe the charge pump one.
Custompanel.xml - pyVCP button layout (as PostGUI HAL file)
Classicladder File - sorts out the logic and debouncing of the touchprobe (allows single button touchoff)
Main INI File - Base & Servo periods, scales for axes (X needs tweaking), homing, limits. MDI commands for touchoff and other PyVCP buttons.

[Tom]

I finally got around to replacing the dodgy original MDF router mount with a shiny "John S" type. An evening with an alu block and a mini-lathe is all it took.

It has (obviously) massively improved the quality of cutting, and I can just just just cut aluminium now. Though 0.3mm depth of cut doesn't really count as cutting. Closer to vigorous polishing, but it's progress. :smile: Well chuffed.

Off to post a separate Q about dust extraction now....