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

[helicop]

125%, 150% and even 200% feed rate override is very doable with a properly designed and built CNC machine. I once ran my router to 200% when I was surfacing the spoil board. I bought a new 2-1/2" surfacing bit and wasn't sure how fast I could push it over my old 1-1/4" surfacing bit. So when I first tried out the larger bit I used the same feed rate as my smaller 1-1/4" bit to start out and then I slowly increased the feed rate while it was cutting to see how fast I could go and then I could edit the G code later with the new feed rate. All three axis ran just fine at 200% but I'd never do this for any other reason. My machine in my garage is an Italian made, Holz-Her industrial CNC router that only has a 3X5 cutting envelope but it weighs more than my car and I retrofit it with Clearpath servos with the proper power supply voltage and current. It's basically bulletproof.

I ask it again, did you test my testfile with your 100% tunned cnc router? Please send a video to show it on 150% feedrate.
Take also a look on the graph I posted.

[ShawnM]

125%, 150% and even 200% feed rate override is very doable with a properly designed and built CNC machine. I once ran my router to 200% when I was surfacing the spoil board. I bought a new 2-1/2" surfacing bit and wasn't sure how fast I could push it over my old 1-1/4" surfacing bit. So when I first tried out the larger bit I used the same feed rate as my smaller 1-1/4" bit to start out and then I slowly increased the feed rate while it was cutting to see how fast I could go and then I could edit the G code later with the new feed rate. All three axis ran just fine at 200% but I'd never do this for any other reason. My machine in my garage is an Italian made, Holz-Her industrial CNC router that only has a 3X5 cutting envelope but it weighs more than my car and I retrofit it with Clearpath servos with the proper power supply voltage and current. It's basically bulletproof.

I ask it again, did you test my testfile with your 100% tunned cnc router? Please send a video to show it on 150% feedrate.
Take also a look on the graph I posted.

Ok then I'll ask again, please share a pic of the label on your power supply(s) and the label on your motors so we can see how your machine is powered.

Running your file on my machine proves nothing. I could send you a file that you could run at 200% on your machine, what would that prove? I loaded your file but when I graphed it I got errors and I stopped there. That's as far as I will go because I don't run other people g code on my production machine for MANY reasons.

I know what my machine is capable of and what it's not. I've built a very robust machine with plenty of headroom to machine aluminum and plastics and it cuts beyond my expectations.

[CNCMaryland]

Question for all - let's say I have a file that I run at 1000mm/min. Then I go and change the feedrates to 2000mm/min a minute and it runs flawlessly.

Wouldn't that prove that the machine can run at say 200% then? Would it be safe to assume going back to the original file of 1000mm/min and running that with a 200% override accomplishes the same thing?

[tblough]

The motion planner takes into consideration the accel and decel for each axis at the programmed feedrate. Therefore, doubling the feedrate is not the same as 200% feedrate override.

[CNCMaryland]

The motion planner takes into consideration the accel and decel for each axis at the programmed feedrate. Therefore, doubling the feedrate is not the same as 200% feedrate override.

Ok, that make sense. I assume its safe to also say that if accel/decel is set in the wizard to 0.5, then with an override of 200%, that changes the accel/decel to 0.25s. I can certainly see how that is a problem if a machine can't achieve that level of accel/decel.

I also wonder if stepper versus servo is in play as well.

[helicop]

The motion planner takes into consideration the accel and decel for each axis at the programmed feedrate. Therefore, doubling the feedrate is not the same as 200% feedrate override.

Ok, that make sense. I assume its safe to also say that if accel/decel is set in the wizard to 0.5, then with an override of 200%, that changes the accel/decel to 0.25s. I can certainly see how that is a problem if a machine can't achieve that level of accel/decel.

I also wonder if stepper versus servo is in play as well.

I test this on my machine with accel/decel on 1s in stead of 0.5s. The machine jogging very slowly, but the spikes are not gone and the stepmotors still lossing steps on the spikes. This with feedrate override on 150%.

[helicop]

125%, 150% and even 200% feed rate override is very doable with a properly designed and built CNC machine. I once ran my router to 200% when I was surfacing the spoil board. I bought a new 2-1/2" surfacing bit and wasn't sure how fast I could push it over my old 1-1/4" surfacing bit. So when I first tried out the larger bit I used the same feed rate as my smaller 1-1/4" bit to start out and then I slowly increased the feed rate while it was cutting to see how fast I could go and then I could edit the G code later with the new feed rate. All three axis ran just fine at 200% but I'd never do this for any other reason. My machine in my garage is an Italian made, Holz-Her industrial CNC router that only has a 3X5 cutting envelope but it weighs more than my car and I retrofit it with Clearpath servos with the proper power supply voltage and current. It's basically bulletproof.

I ask it again, did you test my testfile with your 100% tunned cnc router? Please send a video to show it on 150% feedrate.
Take also a look on the graph I posted.

Ok then I'll ask again, please share a pic of the label on your power supply(s) and the label on your motors so we can see how your machine is powered.

Running your file on my machine proves nothing. I could send you a file that you could run at 200% on your machine, what would that prove? I loaded your file but when I graphed it I got errors and I stopped there. That's as far as I will go because I don't run other people g code on my production machine for MANY reasons.

I know what my machine is capable of and what it's not. I've built a very robust machine with plenty of headroom to machine aluminum and plastics and it cuts beyond my expectations.

Very strange! What errors did you get? It's a very simple gcode file, and it gives no errors in cnc12 with my cnc machine. When you don't trust this file, you can always run it in single block mode.

%
(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)
N40 G54
N55 G0 X33.951 Y20.045
N60 G43 Z15. H9
N65 G1 Z5. F1000.
N4815 G3 X86. Y33.2 I-7.2 J0.
N4825 G3 X49.25 Y32.7 I0. J-0.813
N4830 G2 X98.5 Y92.2 I-0.75 J0.313
N4840 G3 X7.8 Y30. I0. J-2.2
N4850 G3 X40. Y7.8 I2.2 J0.
N4860 G3 X92.2 Y14. I0. J6.2
N4870 G3 X86. Y32.2 I-6.2 J0.
N4875 G1 X88.5
N4880 X48.453 Y32.193
N4885 X48.41 Y32.173
N4890 X48.375 Y32.141
N4895 X48.35 Y32.1
N4900 X48.325 Y32.059
N4905 X48.29 Y32.027
N4910 X48.247 Y32.007
N4915 X48.2 Y32.
N4920 X10.
N4925 G3 X8. Y30. I0. J-2.
N4930 G1 Y10.
N4935 G3 X10. Y8. I2. J0.
N4940 G1 X86.
N4945 G3 X92. Y14. I0. J6.
N4950 G1 Y26.
N4955 G3 X86. Y32. I-6. J0.
N4960 G1 X48.2
N29140 M9
N29145 G28 G91 Z0.
N29150 G90
N29155 G0 X0. Y0.
N29160 M30
%

[Nigelo]

helicop, you keep banging on about your test file but ignore the many answers given. I for one am simply not prepared to derate my machine to satisfy your obstinate curiosity. Read what has already been written and try to understand

[helicop]

helicop, you keep banging on about your test file but ignore the many answers given. I for one am simply not prepared to derate my machine to satisfy your obstinate curiosity. Read what has already been written and try to understand

Exactly,
Read what I write, and stop with this kinds of posts.

[ShawnM]

You simply fail to understand or don’t want to understand that the issue is NOT with Acorn or CNC12. The hardware and software are both proven by the thousands of users all over the globe. All the charts and g code in the world won’t help your case. When your machine runs right on the edge of the envelope at 100% and you try to push it to 150% you get………well you know what you get.