3 Axis 900x500mm

Over the last few weeks I've been hanging out in Clive's garage after taking him up on his offer to help me cut the larger plates and assemble a new router to compliment the mini-mill I built a couple of years back - that machine's still going strong and I'm making some good work with it, but I really do need a bit of extra cutting area (my ultimate goal is to build my own bass guitar from scratch - despite already having eleven of 'em :pig: - it's a big part of getting into the whole CNC thing for me).

Clive's done the heavy lifting here - the only area where I managed to make a significantly greater contribution than him was in the biscuit eating and tea drinking department (thanks Mary..!)

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The design is a tweaked version of a tried and tested router he built a while back - there's also been a great deal of CAD/CAM input from Dean, to whom I'm hugely grateful.

It's based on the heavy duty Motedis extrusions which I ordered from Germany.

Attachment 22730

A fairly conventional build - the hardware is made up of the usual suspects:

• 1610 ballscrews on the X/Y with a 1605 on the Z all mounted on the BK/BF bearings blocks. The X and Y axis are geared 1:1.5 (20T pulley on the motor 30T pulley on the screw) while the Z remains 1:1.
• Profile rails are HIWIN HR20s.
• I'll be using AM882 drivers.
• Standard water-cooled 2.2KW spindle with a Huanyang VFD.
• Machine control will be via the newer version of Linux CNC (I get on with it and it looks so much nicer than Mach).

Not sure on the BOB as yet and still undecided on a computer to run it off - I have a (very) old Windows box which I could re-purpose, or I could take a leaf out of Clive's book and squirrel away a MOBO into the control box (nice idea!). Ideally I'd love to run this off a laptop as it would mean no extra monitor to accommodate around the machine - Clive's pointed out that this can lead to issues, such as certain power saving features kicking in (that you have little/no control over) - but I'm totally open to advice here..!

There have been a couple of hiccups along the way - a couple of holes in the wrong place, a ball-nut coming off the end of a ball-screw, but nothing that's fazed Clive - in fact, I re-packed the ball-nut myself and was surprised to learn that it's not that big a deal - I was gutted when it happened, but sit tight, be patient, pop them in methodically and you can have it sorted in half an hour.

Here's a short vid of the machine semi-assembled over at Clive's. The X slides easily as it's not back-feeding against the screw (the ball-nut mount needed shimming so was left unattached). The gantry will get detached for transporting back to mine at some point next week.

https://youtu.be/j7be4KVUXJY

It's coming together. I've been busy making some of the smaller bits and pieces on my mill:

https://youtu.be/MaH4S53SHHs

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And here's a vid showing some of the cutting that went in to these smaller parts. I've taken to using a drilling strategy to cut out large chunks out of the stock so as to avoid deep slotting. I can deep slot, but I'm not a fan - it can get a bit loud for a confined space and it means using a fair bit of WD40 which I'd sooner avoid. The spindle bracket was cut dry, ok - the odd squirt of WD during the drilling routine, but the profiles themselves were cut using only air.

https://youtu.be/9uhBAU68eO0

I'll hopefully darken Clive's doorstep again (if he hasn't tired of me by then) to cut the mounting holes for the spindle bracket - it's a bit too tall for my mill when stood on end.

That's about it for now. I have some video of Clive's machine cutting the larger plates - it needs editing down a bit, but I'll get something up in the not too distant.

There's still plenty to do - homing switches, e-chain, electrics/electronics. In fact there's probably a couple of months left before it's up and running properly - as ever, it's the small things that end up taking time...

I'll post anything of interest as I go...

Wal.

Nice! Drooling!!!

Wal Your too kind:welcoming: I only see one spindle bracket you will need two. :joker: If you get the other cut we can do them Monday.

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Originally Posted by Clive S

Wal Your too kind:welcoming: I only see one spindle bracket you will need two. :joker: If you get the other cut we can do them Monday.

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The other one's still hidden inside the piece of ali that the first one's standing on. I'll be starting it in the next hour or so - need to eat some biscuits to get me in the mood..!

See you soon!

Wal.

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Quick update.

Spindle brackets about finished:

Attachment 22796 Attachment 22797

Thanks once again to Clive for helping out with the drilling and countersinking of the mounting/clamping holes - these one-piece brackets are a smidge too tall for my mill so it was a real help to get that bit done over at his place.

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I've spent a bit of time this week making some NEMA23 motor covers. See that large chunk of plastic..? I spotted it in a scrap bin outside an industrial unit coming out of band practice last Sunday. I didn't just want to take it, so I drove back in the morning and asked if I could have it - the answer was 'yep' and I've been chuffed about it ever since - 750x220x50mm - got to be the skip find of the month, huh? Not sure what it is, but it cuts very well... I've got a feeling that it might be worth trying to cut this conventional as opposed to climb. The 6mm cutter's quite aggressive and the material is surprisingly hard, so I've kept the DOC/step-over quite conservative. Here's a vid:

https://youtu.be/5LEZ6qsTqFc

The cut's not as clean as I'm sure it could be, but the burr knocks off very easily with a bit of wire wool/fine sand-paper. I tried using a t-slot cutter for the under-cut (where the wires come out of the motor body) but even with the spindle at 3krpm it was still way too hot - I'll use aluminium caps to seal 'em up - an extra step, but it'll work - here's a bit of 3D to show you what I mean:

https://youtu.be/hg8wP8PaV7I

Still want to try making these covers out of some walnut I've got lying about (much to Clive's amusement) - no reason why a decent hardwood shouldn't work, eh.?!

Wal.

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Still want to try making these covers out of some walnut I've got lying about (much to Clive's amusement) - no reason why a decent hardwood shouldn't work, eh.?!

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:tickled_pink: Re the T-slot cutter for the sake of others I have done plenty of these but the cutter needs to be spun at 600-1000 RPM.

Going to be a very nice machine, Keep up the good work and vids.

Those covers for your motors are going to add mojo! Nice touch!!!

very nice and simple could kill for a machine like that right now, but think its at least 3 projects away.

Covers pretty much finished now - just waiting for a bunch of 16mm cable glands to arrive (in black) and then I can pair up and solder what's coming out of the motors onto lengths of CY cable. (Of course, the walnut covers will be getting brass cable glands...) A couple more pics:

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...and a vid showing the machining off of the extra bit of plastic that was used to clamp to whilst cutting the main body along with a quick bit at the end showing the cutting out of the alu caps:

https://youtu.be/2sRNIWZo0OM

Next job is to fit the e-chain, I reckon.

Wal.

Started on the Y-Axis E-chain earlier today. I've got a length of chunky alu L-section that I rescued from my Dad's shed a while back and it's pretty much the ideal size for this job - well, maybe a little on the heavier-duty side...

First job was to drill and tap a hole on one of the plates that makes up the side to side moving part of the Z-Axis. Rather than take the whole thing apart, I used the plate edge tapping kit I 'designed' and had made by Dominic when I first joined the forum. Worked nicely...

Attachment 22817 Attachment 22818 Attachment 22819

Then I machined a little (0.6mm) step into the L-section, this'll prevent it from slipping/rotating without having to use two bolts.

Attachment 22820 Attachment 22821 Attachment 22822

I attached one end of the E-chain - looks alright so far. Space at a premium at this end of the axis as I need to get a little bracket in there somewhere for the limit switch...

Attachment 22823 Attachment 22824

Next I need to make a 7mm spacer that will sit between the L bracket and the extrusion at the other end of the axis. Should look something like this:

Attachment 22825

Again, recesses and proud bits are to prevent it (and the L-section) from rotating once bolted on.

There'll be another bit of L-section positioned somewhere in the middle to prevent the chain from sagging...

Wal.

A little more progress today - I might have got a bit more done, but there was a bit of a fire in my neighbours house while they were out walking their dog - I smelt burning plastic, saw a few wisps of smoke coming from an open window and called the Fire Brigade. A laundry basket left on the stove, apparently...

Firemen did a great job. Loads of smoke but no severe damage - I imagine that there'll be a fair bit of scrubbing to do over the next few days...

https://www.youtube.com/watch?v=_PQrRWSsuc0

Anyway. I made a couple more of the L brackets, these needed slotting for a bit of built in adjustment - nice to have those extra long 5mm end-mills to hand...

Attachment 22842

Then it was on to the spacers. First I machined a channel for the L-bracket to sit in - the channel would also locate onto a fixture so that the reverse could be machined in order for the spacer to locate into the extrusion:

https://youtu.be/d3SXDZDjzyI

Attachment 22840

It's looking like it should work okay:

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One thing I have noticed is that I won't have as much cutting area as what I say in the title of this build - despite the Y gantry being 670mm across, it's going to be more like 460mm rather than 500. I can see myself having to go lock to lock with the Y axis - and as a consequence I think it's a bit hopeful trying to squeeze in the limit sensor on a bracket of some sort. I'll take out the existing support and cut a section out to accommodate the sensor. Ideally the hole would be a bit lower, but bugger it - I'll make the targets a bit bigger.

Attachment 22838 Attachment 22839

That's about it for now - the other E-chain should be a bit more straightforward, so I won't bore you with progress on that one.

Wal.

Support bracket modified to take a sensor:

Attachment 22846 Attachment 22848 Attachment 22847

It's not a pretty effort. In retrospect I didn't need to put the hole right at the edge, worrying about the sensor being able to pick up a target - I could have placed it further in-land (dodging the existing horizontal screw holes) and made the targets tall thin bars secured into the extrusion with countersunk machine screws to keep it low-profile. That would have been the more elegant solution, for sure. Ah well, it works and I can always make a new one later on, though I probably won't..!

Nice video Wal (post#9). Like the speeding up bits !

The rest of it is progressing nicely. There is almost as much time spent on kitting it out as making the basic frame work, so hang in there.

Nice looking build! Do you have a log of your previous mini-mill build by any chance?

Cheers guys.

Thomas, I don't, I'm afraid - I have various bits and pieces which I've wanted to compile, but they're spread over various drives etc. The mini-mill, despite its shortcomings continues to serve me well - if it helps I'll attach a .pdf of the main frame structure. After that it was just a case of buying 4x20mm ecocast plates and getting them drilled at a local shop (not sized, just drilled) - to accept rails and bearing housings etc. The idea was then to use shims to square up the plates as best as I could relative to each other - kinda worked - well, it's a bit out, but at the sizes I work at it's not that big a deal - where I do need better squareness I skew my drawings by a small amount (what I've been able to measure) before making the toolpaths - yep, it's an imperfect workaround but gets me close enough..!

The idea behind the mill build was to make it as easy as possible to put together, while at the same time being able to have a closer look at the hardware (and learn a bit more about how these things are put together..) I wouldn't copy what I've done - it certainly works and gets me some excellent results, but having learnt from it I'd do a few things a lot differently..!

Wal.

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Hi Wal, thanks for the reply. Shame there's no log, I could spend hours reading about other people builds!

Considering it was made in a relatively simple way, it looks a very capable machine. I'm looking forward to seeing the end result of your current project!

Got a couple of jobs done in the last couple of days. Finished the e-chain that runs beneath the bed and is attached to the X-axis - a brief and rather lacklustre vid here:

https://youtu.be/a0B4Cv9uWHI

The fixed end that travels uses a similar spacer as the one I made earlier in the thread - that way the chain stays horizontally level. There's an additional support bracket halfway up the bed, I had to nibble a bit of it away as it fouled the ball-nut housing:

Attachment 22875

Another thing I thought I'd have a look at is creating a mechanical union between the router and the bench that it's sat on - I was going to screw some strategically placed blocks down to prevent it from walking but thought that I might as well add some mass to the unit as a whole and leverage the weight of the bench (and all the stuff that'll eventually get stored down below) to help hold the router down.

I took the feet off and drilled/tapped a couple of M8 holes in the middle 'foot' - too late to use the corner 'feet' - lack of space notwithstanding, I'm not strong enough to lift the router off by myself - I could have attempted a bit of a balancing act, but laying out on the steel L-section would have been, at best, a very awkward affair...

Attachment 22872

Next I drilled a couple of 8.1mm clearance holes for the bolts:

Attachment 22873

And then bolted the router bed down to the bench sub-frame.

Attachment 22874 Attachment 22876

There will eventually be a third plank running up the middle of the bench - I'm leaving it out for now so as to be able to get access to the underside when needed.

Waiting for CY cable and switches to arrive now...

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Originally Posted by Wal

There will eventually be a third plank running up the middle of the bench - I'm leaving it out for now so as to be able to get access to the underside when needed.

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One problem i found with my mini-mill build - the base was almost identical to yours - was that when mounted, you could not get to the screws underneath for service/lube etc. If i was ever to build another i might fit some nylon pipe to the ball nut and run it through the chain to the outside world so it could get a few pumps of grease/oil at service time.

Attachment 22877

Nice build Wal. Dean's a great guy when it comes to inspiration and great design advice. My machine is up and running very nicely! (see here) It will be good to see some footage of it running when completed.

BTW how are you wiring your proximity switches? are they NPN, Are they connected to a 5v break-out board? I've been trying for ages to get mine to work and I'm stumped!

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BTW how are you wiring your proximity switches? are they NPN, Are they connected to a 5v break-out board? I've been trying for ages to get mine to work and I'm stumped!

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Mike best to start and ask again in your thread http://www.mycncuk.com/threads/10262...oes-nt-it-work.

And give us the relevant up to date info.

Hi Mikey,

Nice vid - running very nicely..!

Right - regarding the switches, firstly you must understand that I'm an electronics dunce, the little I do manage to learn tends to get overwritten fairly rapidly :(

I'll be setting up my switches on this machine in a largely similar way to how I've done 'em on my mini-mill - the big difference will be in the type of switch - I'll be using three of these (NPN):

http://www.ebay.co.uk/itm/263081103449

...instead of the small red switches - which are great, but fairly fragile...

Each switch, as you know, has three wires, LN and sensing(?) which sends the triggered signal.

Here's what happens in my set-up.

The wires from all switches run back to this black box:

Attachment 22967

...where they connect to an RJ45 BOB - all L's go to 1, N's go to 2 and sensing goes to 4.

Back inside my main control box there's another one of these RJ45 boards where I've connected a 12VDC supply (don't use a 5V - I understand that the lower voltages are more susceptible to crosstalk/errors) to pins 1 & 2 whilst pin 4 connects to one of the limit switch points on the main BOB. My Linux CNC .ini file is configured to look for a home/limit trigger from just one pin - there's a reason I did it this way, but I can't for the life of me think why, maybe I was just being lazy, which is more than likely... In practical terms what this means is that my axis can't home simultaneously - Z goes first, then X then Y - in all honesty you probably want Z up and out of the way during a homing routine anyway... It also means that if you hit a limit on one axis you'll get three joint errors - it's not the tidiest of set-ups but it certainly works..!

Not sure how helpful my rambling is to you - maybe your issue is more software related - like Clive says, asking on your thread may get you more relevant answers!

All the best.

Wal.

I like the idea of the internal cable chains... neat way to do it.

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Originally Posted by Zeeflyboy

I like the idea of the internal cable chains... neat way to do it.

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I merely followed the ways of Clive and Dean...

The only potential drawback I see, is if I use a hugely over-length bolt for fixturing - anything that protrudes 12mm or so below the left underside of the bed could potentially foul the chain.

Hopefully there'll be none of that nonsense... [emoji1]

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