I'm using Mach3 on my PP . I can't go higher than 40ipm or I get round corners like it's nobody's business. I get them mostly on one side only. There are 'two' corners. One is cutting on x and transitioning to y and one is cutting on y and transitioning to x.

My corners are round on the former, cutting on x transitioning to y. The latter are perfect. I know it's acceleration problem since the x is geared down and y is a direct drives.

My question is what setting other have. I'm trying to mentally think and solve the problem but I'm just not getting it. I think I have to increase the x acceleration, since it takes it longer to come up to speed (because of the speed reduction) but I'm not sure.

Any body else runs Mach3 on the PP ? It could be that the USB CNC setup is the same but I'm not sure.

 

Yes, please check your settings. I'd like to know why I can't cut faster than 40ipm without getting round corners. As I've said, it's only one corner, the one transitioning from x to y.

 

Your Mach3 must be in constant speed.
Go to "General Logic Configuration" and select "Exact Stop" in "Motion Mode"

Edit in Gcode:
G64 (constant speed) for G61 (exact stop)

Exemple:
%
(Generated by PhlatscripT {trunk})
(Bit diameter: ~ 3,2mm)
(Feed rate: 2540,0mm)
(Material Thickness: ~ 6,3mm)
(Material length: 558,8mm X width: 1066,8mm)
(Overhead Gantry: false)
(http://www.PhlatBoyz.com)
G90 G21 G49 G61
M3 S15000
G0 Z3.175
X82.136 Y86.549 Z3.175
G1 Z-8.890 F2540
(move y= 25.823770 GT max of 558,8mm)
Y558.800 Z-8.890
(move y= 25.823770 GT max of 558,8mm)
X596.211 Y558.800 Z-8.890
Y86.549 Z-8.890
X82.136 Y86.549 Z-8.890
G0 Z3.175
G0 X0 Y0
M05
G0 Z0
M30
%

Hugs ...

 

Marco, the problem with the G61 is that it slows down the process and you have no speed gains over the normal code (without the G61) at 30 inch per minute (ipm). If you have a circle made of 26 segments it will stop 26 times. Not good. I hope rcav8r will remember to check his setting.

 

Wrong!
It will not stop 26 times, Mach3 will slow as necessary to make the turn to the true path.

There is no free lunch, you gain something and lost another
Or you use a constant speed with a loss on the path or use the exact stop with deceleration in hard cornering.
With exact stop and a good fit of accelerations in Mach3 (compatible with the inertia of the machine) can be a good top end speed
Hugs

 

Thanks,guys, I'll try it and we'll see how it goes.

Edit: I feel like such a tool. When I've set up my PP I made all the accelerations equal. When I went to put the rcav8r posted I saw that for some reason the setting was three times as fast for the x as for the y. No idea how that had happened but that, of course was the culprit. I set the accel to 40, as posted above and ALL the corners are, of course , square cutting at 100ipm. I'll try higher ipm next.