Game on!

[Voicecoil]

I'm not too worried about the strain relief (the supplied one wouldn't fit over the cable!) as I've added a couple of layers of adhesive lined heatshrink over the cable so the clamp is pretty damn tight now, and the last inch or so of the cable has been stiffened up a lot. The heat transfer is an interesting point, I'll keep an eye on that, if necessary up the cooling - easy to add some finned extrusion to the pot and up the pump speed. As mentioned above, having to bundle the water pipes and spindle drive together and take them through the bushing wasn't really intentional!
The Z-axis design was done that way to keep things compact and the spindle axis as close to the gantry as possible (it's saved between 40 and 50mm off a more conventional design), and was partly inspired by Routercnc's machine. Should see how well it works in a few days once I've got the VFD programmed.....

[JAZZCNC]

The Z-axis design was done that way to keep things compact and the spindle axis as close to the gantry as possible (it's saved between 40 and 50mm off a more conventional design), and was partly inspired by Routercnc's machine. Should see how well it works in a few days once I've got the VFD programmed.....

Ermm not sure if that gain alone will be worth it.? It's going to make tramming the spindle an absolute bitch of a job. Accurate Alignment of rails, ball-screws, etc looks much more difficult.
Also, the bearings being sat on thin edge-mounted plates will allow more vibrations into the spindle.

Don't get me wrong I'm sure it will work fine but the conventional approach would have been stronger and easier to setup. I also think it's a bit of a wasteful design.? In that doesn't require 2 screws which cost extra money and also put excess load on the motor robbing it of performance.! . . . I'd rather have it simpler, stronger and more efficient than save 40mm travel if I'm honest.

Sorry to be negative about it, . . . But I'd rather say it than think it, then sees someone else copying it thinking it's better because saving travel without seeing the negatives I see. I

You made a nice job of it thou well done..

[Voicecoil]

Ermm not sure if that gain alone will be worth it.? It's going to make tramming the spindle an absolute bitch of a job. Accurate Alignment of rails, ball-screws, etc looks much more difficult.
Also, the bearings being sat on thin edge-mounted plates will allow more vibrations into the spindle.

Don't get me wrong I'm sure it will work fine but the conventional approach would have been stronger and easier to setup. I also think it's a bit of a wasteful design.? In that doesn't require 2 screws which cost extra money and also put excess load on the motor robbing it of performance.! . . . I'd rather have it simpler, stronger and more efficient than save 40mm travel if I'm honest.

Sorry to be negative about it, . . . But I'd rather say it than think it, then sees someone else copying it thinking it's better because saving travel without seeing the negatives I see. I

You made a nice job of it thou well done..

[AndyUK]

Looks like a nice tidy job!

*goes back to my spindle and gets some cable braid out*

[Voicecoil]

To be honest, it wasn't just a desire for neatness :blush: Having painted myself into a corner with feasible belt paths on the Z-axis I came up with the idler-with-the-cable-through-the centre idea. Problem was, the cooling pipes tended to have a bit more friction through the bushing than I was comfy with - the cable braid is a lot more slippy and makes everything move a lot more freely .

[Voicecoil]

The spindle of course needs cooling water. After a long and fruitless search on the Bay of fleas for a suitable flat sided metal pot, I made one out of a bit of 100x100x2 ali tube that's been at the back of the workshop for ages. Add a pump + flow switch and everything's cool

[Voicecoil]

Tramming's not such a bad thing as might appear - the vertical blocks that the Z-axis Hiwins are attached to have increasing clearance hole diameters from 6.1mm (bottom) to 6.6 mm bot( top) to allow some side to side movement at the top to get it square. And they make the Z-axis plate seriously chuffing rigid top to bottom-wise. Front to back tramming (which would always seem to be a bugger on a gantry machine to me) was done using the end fastenings on the gantry and a bit of shimming As regards the bearings being on thin plate, that was a result of me not having much in the way of machining facilities, the top plate and a few other bits are due for a re-make once I have it making chips, with thicker material and better alignment once I can sink the bearings and the motor into the plate.

[JAZZCNC]

Tramming's not such a bad thing as might appear - the vertical blocks that the Z-axis Hiwins are attached to have increasing clearance hole diameters from 6.1mm (bottom) to 6.6 mm bot( top) to allow some side to side movement at the top to get it square.

In that case, you are bending the ball-screws because they are fixed to the top plate while the bottoms are fixed to the upright plates which your moving causing a twist on the screw. Also, the ball-screws must stay aligned perfectly parallel to the rails which they cannot do this way because you have them fixed to the top plate.

This design fails the golden rule of DIY to me.? Which is build-in Adjustment, adjustment, adjustment and bit more adjustment just for good measure?

And they make the Z-axis plate seriously chuffing rigid top to bottom-wise.

Pointless if they cause vibrations through the spindle, which they will do compared to if they were fixed directly to backplate like on conventional design. You could also use a similar supporting strip on the rear plate if felt it was needed on conventional design but without causing vibrations.

[Voicecoil]

In that case, you are bending the ball-screws because they are fixed to the top plate while the bottoms are fixed to the upright plates which your moving causing a twist on the screw. Also, the ball-screws must stay aligned perfectly parallel to the rails which they cannot do this way because you have them fixed to the top plate.

This design fails the golden rule of DIY to me.? Which is build-in Adjustment, adjustment, adjustment and bit more adjustment just for good measure?
.

Well, the holes that secure the top plate to the back plate are a bit oversized to allow the bit of L to R adjustment whilst the idea is that the top of the side blocks and bearings stay fixed relative to each other - and after all the position where tram is spot-on should be when everything is perfectly aligned at 90 deg. If I were to do it again I would likely split the back plate into 2 stacked thinner plates to make assembly and tramming easier, but right now the important thing is to get this one up and running.And whilst it took a couuple of goes round the loop to adjust it all to get it running smoothly, it does basically work, it goes up and down quite happily apart from a slight wobble on one of the pulleys which I seem to have managed to bore out slightly off-centre, that's a job for tomorrow.

[Voicecoil]

So the last few days have been a "getting it all working" scenario. First off was a power problem: I'd had some issues with the control box and other gear (typically with big SMPS) tripping out the RCCB in the workshop, and as soon as I tried to power up the VFD it did it every time. Investigation showed that the whole workshop was on a 30mA trip, fine for a domestic ring main, but unlikely to be stable with a couple of big EMI filters on the line, I've come across such issues before. Thankfully I have a humungous (1.5KVA) isolation transformer I use when developing switch mode supplies, putting that in the line has at least enabled me to get going. looks like I'm going to have to have a word with the estate to get a more realistically rated breaker fitted Then came the joys of programming the VFD (a Sunfar 300 - the more usual Huanyang doesn't go high enough for a 4 pole spindle), although the manual (or at least the newer version of it) isn't so bad there's a couple of things that vary between ambiguous and rather misleading. Anyway finally I've managed to get the spindle spinning (and the right way round!!) and sorted out stopping and starting from UCCNC. This showed up and interesting twist in that for survivability's sake you need a high voltage open collector O/P from the AXBB-E to switch the spindle On/Off as it's switching something that seems to vary between 5.5 and 6.5V; OK so you could use one of the Port 2 isolated outputs. BUT the switching input is referred to the 5V/processor ground on the AXBB-E through the 0-10V speed control line, NOT the 24V "machine" ground that the isolated outputs run from, so the choice is to either common all the grounds up, or get creative: I chose the latter and added a wee MOSFET on the output of Port1 p17 to buffer it. Then lastly I had some issues with limits triggering when the spindle started, after some parping about this was solved by tying the 24V ground to earth but floating the 5V ground.