no, nothing mechanically is in the way. I’ve tried different belts, different motors, it homes, fine, its only cutting pockets. I’ll attached the cgode.
2x audi 220x300 pocket and design for viewing.pdf (291.2 KB)
Here is the exact gcode file that i was using. This file works on my other CNC. the only difference is one is new and runs CMv4 and GRBL 1.1
Thank you for all your help with this
Try cutting your Z rapid and acceleration in half.
$112=2500
$122=200
how do i change that, i thought it was locked in v4?
In the MDI, type one setting in at a time
If the G-Code works on a different machine, it’s not the G-Code (but see below).
It’s either some difference in the electronics (check for wiring faults) or something mechanical.
One possible consideration is that an SO3 and an XL/XXL have different vertical travel — could you be bottoming out at the top stop?
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^^ I thought that regarding the travel. Its a XL and and CMv4 thinks its a SO3, so i had to change that, but then shouldnt that fix it.
The profile cuts I make on it can go down 10mm past the pocket, so it has travel. i’ve also added more waste board, adjusted the location of the router etc. its just when it goes up clunks and its the motor skipping, not the belt. Same as if you try to go down, hit wood and it makes the clunking sound. All the wires seem ok, one was snagged in the y2 motor and broken when I got it, but I fixed that. all others seem fine.
I’d also say that it retracts the 3 or 4 times before this happens perfectly. Its always on the final pocket cut that it doesn’t lift fully. it clunks then carries on with the file, but now set about 10mm to low so it destroys the product.
In that case, check the mechanical aspects of cutting — usually what happens in this sort of instance is the endmill is loose, or belt tension is low, and the endmill or router are pulled into the cut over time.
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done all that, tried multiple belts, all tight, new set screws, up cut bit (same I’ve been using for 2 years and its brand new) Collet is so tight I’m surprised it didn’t break.
The cut isn’t bad, its perfect in fact, its not until it tries to lift and then do a final edge pass that it doesn’t lift.
I sanded the Z rails, swapped out the v wheels, made sure both CNC’s felt the same unplugged when lifting the Z axis… I clear the wood chips so nothing is binding the wheels, and nothing is stuck on the pulleys.
Any heres the thing, it still starts the retract, it just only goes up about 5mm. It goes up enough to clear the pocket bottom its just cut, then clunks and stops, then carries on with the file low…
So it starts the clunking completely free of wood or anything. speeds and feeds are set the same on both CNC’s and i’ve even slowed it right down on the new one and it made no difference.
I feel like i’m out of idea’s as I’ve already experienced just about everything with the other CNC over the past 2.5 years.
Can you replicate the same behavior with a rapid move?
Home the machine, set your Z zero at your wasteboard, and then send (assuming millimeter mode)
/G53 G0 Z-5
That will tell the Z to move to 5mm below the limit switch as fast as your settings allow (same as a retraction).
If you use inches, change the -5 to -0.2 or thereabouts.
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cool trick, but nope, moves smooth and perfect.
Try several times. If it continues to work, then it’s just the cutting force at some point. You may be losing Z gradually and not noticing it during the cut.
I’d try a test, say a 10mm deep pocket, and measure the depth.
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I just did the up down 6 times, each time perfect. Also measured the file that I last cut that went wrong and its exactly level, 12mm deep all round, cut in 4 passes, 3mm each pass.
I’m honestly at a loss. I made a mini guitar shape last night and it worked (took 8 min to make). the files I normally make take about an hour each. You think that either voltage or heat or something may affect it?
its always on the 4th or 5th pass (starting) that it goes wrong, so about 30 min to the cut.
Both can. The motor would have to get really hot. Can you put your hands on it for a couple seconds? The driver is on a giant heat sink.
Can you measure your source voltage?
Did you try reducing the rapid speed and acceleration? Not the source of your problem, but it may help until the source is discovered.
yes tried reducing the speed using the codes you put in above. no change.
I have got another upgraded motor here (amazon arrived today) so i’ll wire that in and see if that makes a difference.
I did notice that just using CMv4 to move the z axis there is a small electrical clicking noise, it still travels smooth, but you can hear clicking. the y and x axis dont do this, so i’m leaning more and more towards voltage from the mother board. i don’t have a voltage reader thats accurate to test.
Got the specs? Off the top of my head, the Carbide board only can provide 2 amps.
https://www.amazon.com/gp/product/B00PNEPKH6/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
its this, 1.8 amps. I’m about to try it and see what happens. bolts right up and one of the reviews said they used it to upgrade for a shapeoko so… here goes.
It’s not by chance hitting the top during one of those retracts is it? You mentioned additional waste board. I’ve had this happen before when cutting pockets where during one or more retracts the Z hits the top of its travel, skips teeth or steps, then loses its mind and dives through my material. Check your retracts height, and maybe raise your router and inch or so up in its mount?
Dan
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