VCP Feedrate override problem (stepmotor lossing steps) <don't run jobs above 100% override>

[Gary Campbell]

I see this not as a solution to set the feedrate high and only use the feedrate override to lower the cutting speed. When CNC12 software has a problem with the + button, why didn’t remove the developers this button, or fix this problem?

Short answer: There are some valid reasons for feedrate increases, it is better to train the operator than eliminate the feature.

This "problem" as you describe it is usually not a problem when a machine is performing properly, which it sounds like yours isn't. Answer my questions posted above and you may eliminate the issue.

[CNCMaryland]

I see this not as a solution to set the feedrate high and only use the feedrate override to lower the cutting speed. When CNC12 software has a problem with the + button, why didn’t remove the developers this button, or fix this problem?

Short answer: There are some valid reasons for feedrate increases, it is better to train the operator than eliminate the feature.

This "problem" as you describe it is usually not a problem when a machine is performing properly, which it sounds like yours isn't. Answer my questions posted above and you may eliminate the issue.

I respectfully disagree in general. It would be one thing where it was 1 user that experienced this, but it does seem that multiple people are saying this. I have the same issue, and I 100% think my machine is performing properly.

Have you tested this yourself? I would love to see a video with a 150% feedrate override, operating smoothly.

[helicop]

I see this not as a solution to set the feedrate high and only use the feedrate override to lower the cutting speed. When CNC12 software has a problem with the + button, why didn’t remove the developers this button, or fix this problem?

Short answer: There are some valid reasons for feedrate increases, it is better to train the operator than eliminate the feature.

This "problem" as you describe it is usually not a problem when a machine is performing properly, which it sounds like yours isn't. Answer my questions posted above and you may eliminate the issue.

It did some more investigation, and found a problem. And I will explain my test.

First test:
When I run from de MDI the G1 X0 Y100 F1000 command, it runs ons 1000mm/m. When It set feedrate override on 150%, the same command runs on 1500mm/m. Conclusion is that feedrate override is working with my cnc router from MDI.

Second test:
When I run a very simple G-code program with Single Block on and feedrate override 150%. I discover that on G2 command (see below in bold) the stepmotor bumping and not using acceleration settings. All the other commands are working ok on 150% feedrate.

%
(Machine)
( vendor: TDR router)
( description: Generic 3-axis)
(T9 D=4. CR=0. - ZMIN=-8. - flat end mill)
N10 G90 G94 G17
N15 G21
(When using Fusion 360 for Personal Use, the feedrate of)
(rapid moves is reduced to match the feedrate of cutting)
(moves, which can increase machining time. Unrestricted rapid)
(moves are available with a Fusion 360 Subscription.)
N20 G28 G91 Z0.
N25 G90
(2D Pocket3)
N30 T9 M6
(TDR VHM 4 mm end mill)
N35 S14000 M3
N40 G54
N45 M7
N55 G0 X33.951 Y20.045
N60 G43 Z15. H9
N65 G1 Z5. F1000.
N70 Z0.2 F150.
N75 G2 X35. Y21.05 Z0.172 I1.049 J-0.045 F1000.
N80 G1 X70. Z-0.439
N85 G2 Y18.95 Z-0.497 I0. J-1.05
N90 G1 X69.8 Z-0.5
N95 X35.
N100 G2 Y21.05 I0. J1.05

N29140 M9
N29145 G28 G91 Z0.
N29150 G90
N29155 G0 X0. Y0.
N29160 M30
%

Third test:
I run from the MDI the following commands, with override on 150%. And also on the G2 command problems with (no) acceleration step motors.
Z0.2 F150.
G2 X35. Y21.05 Z0.172 I1.049 J-0.045 F1000.
G1 X70. Z-0.439
G2 Y18.95 Z-0.497 I0. J-1.05
G2 X35. Y21.05 Z0.172 I1.049 J-0.045 F1000.

I look like that stepmotor bumps are on G2 command without F (Feedrate) parameter.

I attach a new report file, and my test G-code file.

[cnckeith]

Run g code programs with the feedrate override set to 100% or lower.

if you find that what you programmed is not moving fast enough at 100%, then changed the G code program and increase the F command value. so that the feedrate override is at 100% or lower while cutting a job.

[helicop]

Run g code programs with the feedrate override set to 100% or lower.

if you find that what you programmed is not moving fast enough at 100%, then changed the G code program and increase the F command value. so that the feedrate override is at 100% or lower while cutting a job.

Hi Keith,
Thats is not the solution of this problem. Look to my post about G2 command. May be you can test this on your CNC machine.

[cnckeith]

Run g code programs with the feedrate override set to 100% or lower.

if you find that what you programmed is not moving fast enough at 100%, then changed the G code program and increase the F command value. so that the feedrate override is at 100% or lower while cutting a job.

Hi Keith,
Thats is not the solution of this problem. Look to my post about G2 command. May be you can test this on your CNC machine.

im not sure what the problem is

[helicop]

Run g code programs with the feedrate override set to 100% or lower.

if you find that what you programmed is not moving fast enough at 100%, then changed the G code program and increase the F command value. so that the feedrate override is at 100% or lower while cutting a job.

Hi Keith,
Thats is not the solution of this problem. Look to my post about G2 command. May be you can test this on your CNC machine.

im not sure what the problem is

Hi Keith,
I did some new tests, And I discover that the G2 and G3 commands not use the stepmotor acceleration settings. I test it with feedrate F parameter behind the G2 commands, but that doesn't matter.
I attached a new test file, when you run this with feed override on 150%, you will probably see the the problem.
May be there are more G code commands with this problem, but G1 seem to work ok.

[cnckeith]

ok. i'll look into it....but, i don't run any G code tests over 100%. as i stated before CNC12 is design to run at 100% or lower when actually cutting.
this is like the RPM tachometer on a car.. you run the engine in the recommended range. will it run out side of the range? sure..but your results may vary. feedrate override above 100% acts like a multiplier, like an amplifier, everything gets amplified and multiplied. so any issues caused by any number of things that may not show at 100% but will at 150% or 200% for sure. if the machine is configured on the edge of the happy zone and runs fine at 100% and you amp things up to 150% you could see something show up. that being said i'll look into your findings and try to figure out what you are seeing.

[Gary Campbell]

Not running most any controller over 100% is like machining 101. That said, your results may be exacerbated by not using the optimum settings or setup on the machine. Even tho it's not recommended, I'm sure that dozens, hundreds, maybe even thousands do it every day.

Point being, in most cases there is no reason to be losing steps, even at 150% of a normal set feedrate. Your feedrate didn't seem to be out of the ordinary, but losing steps is. I'm sure Centroid will look into their end of this issue, you should do the same.

[helicop]

ok. i'll look into it....but, i don't run any G code tests over 100%. as i stated before CNC12 is design to run at 100% or lower when actually cutting.
this is like the RPM tachometer on a car.. you run the engine in the recommended range. will it run out side of the range? sure..but your results may vary. feedrate override above 100% acts like a multiplier, like an amplifier, everything gets amplified and multiplied. so any issues caused by any number of things that may not show at 100% but will at 150% or 200% for sure. if the machine is configured on the edge of the happy zone and runs fine at 100% and you amp things up to 150% you could see something show up. that being said i'll look into your findings and try to figure out what you are seeing.

Hi Keith,
Please do the test on 150%, and you will see the problem directly.
When CNC12 is designed to work only till 100%, then is my question why the feedrate override + button is on the VCP panel, and also the max feedrate override setting/parameter in the setup wizard. When CNC12 using the stepmotor settings in de setup wizard, there is no problem at all, because when override will be higher as the stepmotor max settings it’s limit the movements. But every stepmotor will losing steps when the cnc12 not using acceleration, because the torch moment will be to high.
But a good software design will prevent that stepmotors losing steps when the user are pressing on a button. And CNC12 is very good software, and there are always bugs to fix.