routercnc_MK3

[routercnc]

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 !
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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).
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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.
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Here is the proof:

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And here is the new unit (the one on the right):

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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.
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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.
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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]

Coming along nice Barry hopefully no more troubles.!

[routercnc]

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!


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).


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.


It should look like this when finished:


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]

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.



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]

Its coming along nicely when's the party ..Clive

[Neale]

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]

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:


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

And the rest of the machine:


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:


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:




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:




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


Then drilled a matrix of M6 holes for the clamps:


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]

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.
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Big thumbs up. Happy New Year