Questions on using a moving gantry style mini-mill...

I wonder how you take so brave cuts and meanwhile try to tune your mist system....:boxing:


Why just you dont cut a 50x50 mm pieces and figure there the speeds, feeds and mist system.



Here are some tips, you could say cornerstones:



-mist system tip should be 0.8-1mm, 2-2.5 bar pressure at reservoir, mist spray length should be 80-100mm if all done correctly. when done correctly it will blow away even when 20mm bit cutting



About the cuts in aluminum. you will continue to snap bits until you don't figure what are you doing. Deep slotting is a recipe for disaster. Make slot double wide so you have space where the chips to go, or go slower.


Start from 12000rpm and ~600mm/min, slowly rise speed and look about the quality of the cut/6mm 2 flute/. But not on big pieces. Make small pieces and test all untill happy, including final slot depth test.


And better more mist than not at all

I leave 4mm thick by 10mm long tabs

Dave this what I meant when said Aluminium bed is Ok but often you'll have Spoil board on it. So here's what I would do.
Fit spoil board that can be screwed into and surface it. Then I would change the Code and move the smaller part in wards and drill holes put screws where I have black circles on your last pick.

Then onion skin the both parts with about 0.3mm. Doesn't matter the large part will not be held down one side the rest will old it.

The skin then just breaks away and quick cleanup with De-burr sorts what's left.

I do this type thing all the time in shity 1050 2mm plate and works perfectly.

Attachment 18066

Points noted Boyan, BTW the coolant is working nicely - the cutter was clear even during the heavy cuts.

Jazz, the two screws in the small cutouts - they would be fitted after the finish pass on this features?

Spoilboard - MDF?
What sort/size for facing cutters?

Quote:

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Originally Posted by Davek0974

Points noted Boyan, BTW the coolant is working nicely - the cutter was clear even during the heavy cuts.

Jazz, the two screws in the small cutouts - they would be fitted after the finish pass on this features?

Spoilboard - MDF?
What sort/size for facing cutters?

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Yes screws with washers in cut outs after finish pass on pockets.

MDF, ply anything that can screw into really.

Facing cutter then widest you have but with such small piece then wouldn't take long if small.

Actually to be honest dave if spoil board is resonably flat then just for this job won't even need surfacing because your only profiling. The main reason I said surface is because 0.3mm isn't much so can easily cut thru if not flat but if you want to have thicker skin then don't bother with surfacing.

Disclaimer here .!! . . . You'll need to sort that discrepency in the Z axis if your having 0.3mm Skin so don't blame if your Z isn't fettled.!

Quote:

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Originally Posted by JAZZCNC

Disclaimer here .!! . . . You'll need to sort that discrepency in the Z axis if your having 0.3mm Skin so don't blame if your Z isn't fettled.!

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Thats task no1, I will re-check it with the dial indicator as i cant see how it was going too deep. I know the bed is 0.1mm out of parallel over ints 400mm length but this was too deep at the point i set the tool using my probe plate.

My thinking is that I can set a tool, set zero height using the touch-plate, command G0 Z0.00 and run the cutter over the bed without any more than a witness mark?

The only thing i can see is the steps-per being off in Mach settings.

No2 job is fit and program the new VFD for sensors vector, might help a little, should certainly sort out that odd voltage issue on the 0-10v control, maybe even the lack of power at half speed.

No3 job is to run some tests on small scraps - i seem to have plenty now ;)

While doing all that I will be resigning my parts and maybe ordering some larger sheet stock so that it can be fixed down around the edges easier.

Getting beyond a joke now :(

Being smart ;) I programmed the new VFD at work on a test motor, all went well, nice and easy.

Just about time to fit it when i got home, booted the pc up, pressed the reset button to power up the VFD/spindle and pop goes the breaker.

Reset the mcb, try again - pop.

Ok, thinking there might be another issue here i disconnected the VFD and put a plug on it and plugged in directly - pop.

Now, this is a 32A circuit and I really can't see why a small drive like this should need a slow breaker?

Obviously no time left in the week now to replace the drive, so its a case of putting the dodgy one back now and keeping my fingers crossed.

I have emailed the supplier as they were shut by the time I came in from the shop.

Things shouldn't be this damn difficult, doing my head in now ;(

Busy time of day so, do you're breakers have an undervoltage trip? If so, something heavy starting up might be causing a dip sufficient to drop the breaker out!

Additional thought, VFD's generally default to a very fast ramp-up time, people never turn it down sometimes fixed just by changing the ramp up time.

Doubt it, just the bog-standard 32A MK mcb.