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different max speed for rapid and feed movement?
11 Nov 2012 21:19 #26454
by helig
different max speed for rapid and feed movement? was created by helig
Dear all
I understand that I can define a max velocity for each axis in stepconf and that this commands rapid movement (G0).
Question: How can I define another (lower) max velocity limiting the programmed feed movement (G1, G2, ...) for each axis?
(Hints to doc where I could have found this info are appreciated)
Thanks and regards
Volker
I understand that I can define a max velocity for each axis in stepconf and that this commands rapid movement (G0).
Question: How can I define another (lower) max velocity limiting the programmed feed movement (G1, G2, ...) for each axis?
(Hints to doc where I could have found this info are appreciated)
Thanks and regards
Volker
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11 Nov 2012 21:33 #26455
by ArcEye
Replied by ArcEye on topic different max speed for rapid and feed movement?
Hi
This outlines the velocity settings
linuxcnc.org/docs/2.5/html/config/ini_config.html
You can set max velocity, stepgen max velocity and default velocity.
The former sets your max G0 rate, the second allows stepgens to exceed this to bring off co-ordinated moves within the required feed rate and the latter defines the default slider position and jog rate for axes.
The feed rate for other moves is solely defined by the F value in your G code, to the limit set in max velocity, AFAIK
regards
This outlines the velocity settings
linuxcnc.org/docs/2.5/html/config/ini_config.html
You can set max velocity, stepgen max velocity and default velocity.
The former sets your max G0 rate, the second allows stepgens to exceed this to bring off co-ordinated moves within the required feed rate and the latter defines the default slider position and jog rate for axes.
The feed rate for other moves is solely defined by the F value in your G code, to the limit set in max velocity, AFAIK
regards
The following user(s) said Thank You: helig
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12 Nov 2012 03:10 #26460
by andypugh
Replied by andypugh on topic different max speed for rapid and feed movement?
I don't think you can. Why do you think you need to?How can I define another (lower) max velocity limiting the programmed feed movement (G1, G2, ...) for each axis?
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12 Nov 2012 06:55 #26465
by helig
Replied by helig on topic different max speed for rapid and feed movement?
Why do I think I need to?.
I use a DIY 3-axis mill to cut wood with inexpensive cutters.
I have found that I can do let's say 700mm/min feed when cutting in X or Y direction, but I'm losing steps when cutting more than 200mm/min in Z direction.
Anyhow max Z speed for rapid movement is beyond that.
I want to do a helical G2 movement cutting into wood. XY plane selected with G17.
If I could limit Z speed for G2 (and all non-G0 movements), then I could use F700 for the coordinated G2 movement without bothering about Z because the machine would slow down XY movement accordingly when Z speed limit was reached. Otherwise I have to calculate the speed limit for the F-word in my procedure.
(btw: I've already done the speed-limit calculation - no need to help me with that)
I use a DIY 3-axis mill to cut wood with inexpensive cutters.
I have found that I can do let's say 700mm/min feed when cutting in X or Y direction, but I'm losing steps when cutting more than 200mm/min in Z direction.
Anyhow max Z speed for rapid movement is beyond that.
I want to do a helical G2 movement cutting into wood. XY plane selected with G17.
If I could limit Z speed for G2 (and all non-G0 movements), then I could use F700 for the coordinated G2 movement without bothering about Z because the machine would slow down XY movement accordingly when Z speed limit was reached. Otherwise I have to calculate the speed limit for the F-word in my procedure.
(btw: I've already done the speed-limit calculation - no need to help me with that)
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12 Nov 2012 07:53 #26467
by cncbasher
you will probably find this is more a mechanical issue than software , or down to the type of cutters you are using ..
also look at reducing the default velocity in the [traj] section of your z axis in your INI file .
if your loosing steps or missing steps theirs a reason for it . be it stepper performance or mechanical issues
or just plain running the machine outside it's physical capabilities or performance
Replied by cncbasher on topic different max speed for rapid and feed movement?
Why do I think I need to?.
I use a DIY 3-axis mill to cut wood with inexpensive cutters.
I have found that I can do let's say 700mm/min feed when cutting in X or Y direction, but I'm losing steps when cutting more than 200mm/min in Z direction.
Anyhow max Z speed for rapid movement is beyond that.
I want to do a helical G2 movement cutting into wood. XY plane selected with G17.
If I could limit Z speed for G2 (and all non-G0 movements), then I could use F700 for the coordinated G2 movement without bothering about Z because the machine would slow down XY movement accordingly when Z speed limit was reached. Otherwise I have to calculate the speed limit for the F-word in my procedure.
(btw: I've already done the speed-limit calculation - no need to help me with that)
you will probably find this is more a mechanical issue than software , or down to the type of cutters you are using ..
also look at reducing the default velocity in the [traj] section of your z axis in your INI file .
if your loosing steps or missing steps theirs a reason for it . be it stepper performance or mechanical issues
or just plain running the machine outside it's physical capabilities or performance
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12 Nov 2012 09:29 #26469
by andypugh
If you need to keep the Z rapids high, then I don't think there is an easy way (or possibly any way) to do this.
However, setting the Z axis velocity and accel limits to what the Z axis can manage during cuts, rather than what it can achieve during free movement might do what you want.
You might find it makes less difference to rapid moves than you might expect, as typically the Z movement is less that the XY movement during the sorts of rapids where you notice the traverse time.
Replied by andypugh on topic different max speed for rapid and feed movement?
I have found that I can do let's say 700mm/min feed when cutting in X or Y direction, but I'm losing steps when cutting more than 200mm/min in Z direction.
Anyhow max Z speed for rapid movement is beyond that.
If you need to keep the Z rapids high, then I don't think there is an easy way (or possibly any way) to do this.
However, setting the Z axis velocity and accel limits to what the Z axis can manage during cuts, rather than what it can achieve during free movement might do what you want.
You might find it makes less difference to rapid moves than you might expect, as typically the Z movement is less that the XY movement during the sorts of rapids where you notice the traverse time.
The following user(s) said Thank You: helig
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18 Nov 2012 01:37 #26717
by helig
Yes, exactly this was my point - I wanted to tell the software about the limitations of the hardware. Anyhow: the more I think about it I prefer explicitely calculating the optimal speed. Thank you anyway - the statements in the forum were really helpful for me
Replied by helig on topic different max speed for rapid and feed movement?
you will probably find this is more a mechanical issue than software , or down to the type of cutters you are using ..
also look at reducing the default velocity in the [traj] section of your z axis in your INI file .
if your loosing steps or missing steps theirs a reason for it . be it stepper performance or mechanical issues
or just plain running the machine outside it's physical capabilities or performance
Yes, exactly this was my point - I wanted to tell the software about the limitations of the hardware. Anyhow: the more I think about it I prefer explicitely calculating the optimal speed. Thank you anyway - the statements in the forum were really helpful for me
Please Log in or Create an account to join the conversation.
- Configuring LinuxCNC
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- StepConf Wizard
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