loosing steps in 3D only

loosing steps in 3D only

Postby Zerspaner » 28 Mar 2016, 07:45

Dears,

I've the problem that I miss steps in 3d milling.
I've absolute no problems in 2d. It seems that the data is too much in 3d to bring it through USB. Could that be?

It works fine for some time and then steps are gone - no not really - not only a few steps.. we are talking about 10-20mm..

Has someone the same issue?

Thanks


Michael
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Re: loosing steps in 3D only

Postby Support » 30 Mar 2016, 07:24

Please post your settings and your g-code program.

What kind of machine setup are you using? Are lost steps located at the same lines in program?
Have you tried air cutting without using spindle? Maybe this has got something to do with a EMI?
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Re: loosing steps in 3D only

Postby Zerspaner » 30 Apr 2016, 07:59

Dears,

sorry for the delay - we made a few further tests on it - also with earthing and testing without spindle and so on.
Everything without efforts.

So.. meanwhile I've seen that Jerry has a similar problem.
Perhaps we could find a solution together.

Please find attached a file in 2D (found the same problem also here).
There are always steps in Y missing after running this (approx 1mm).

Thanks

Zerspaner
Attachments
Setting Forum 300416.setting
settings
(50.32 KiB) Downloaded 48 times
Versuch 7 Kleeblätter.dxf
dxf of problem file
(105.63 KiB) Downloaded 50 times
Versuch 7 Kleeblätter.tap
TAP of problem file
(52.74 KiB) Downloaded 46 times
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Re: loosing steps in 3D only

Postby Support » 05 May 2016, 09:26

What kind of stepper driver do you use?

The problems can be caused by short moves which can be very erratic if acceleration and speed values are high.

You can use lower speeds and accelerations and also please try re-configuring these settings(File/Settings/Lookahead):

Angle: 170
Radius: 0 ; Angle: 20
Speed Adjust -> enabled
Radial Acceleration value should usually be same as "Acceleration" value from "Axes" setup.
Path tolerance: Depends on your requirements
Path blend: Enabled
Path Range: 5-180

"Initial Speed" should be zero. This is often reason for lost steps because motors start too hard.(Axes/Setup/Init Speed)

Please try your g-code programs with this settings configuration and post the results.
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Re: loosing steps in 3D only

Postby JerryBurks » 07 May 2016, 00:57

Support wrote:What kind of stepper driver do you use?

The problems can be caused by short moves which can be very erratic if acceleration and speed values are high.

You can use lower speeds and accelerations and also please try re-configuring these settings(File/Settings/Lookahead):

Angle: 170
Radius: 0 ; Angle: 20
Speed Adjust -> enabled
Radial Acceleration value should usually be same as "Acceleration" value from "Axes" setup.
Path tolerance: Depends on your requirements
Path blend: Enabled
Path Range: 5-180

"Initial Speed" should be zero. This is often reason for lost steps because motors start too hard.(Axes/Setup/Init Speed)

Please try your g-code programs with this settings configuration and post the results.


O.K., thanks I will try that.

Most of the time I machine 2.5d Vcarve toolpaths and never have this problem, even when creating very detailed tool paths. But in the meantime I tried a similar complex 3d-file flat (without indexer) and had the same trouble. Let's see if the new settings help.

FWIW, my machine has low-inductance 450in-oz NEMA34 steppers on Gecko 203V drives at 72 volt. Actually, the stalling x-axis uses two of them. I know if I just reduce speeds the problem goes away but then the machine is crawling.
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Re: loosing steps (not) in 3D only

Postby Zerspaner » 08 May 2016, 15:07

Dear Support / Andrej,

thanks for your help!
I tried your proposals and it seems to be better, but not solved yet.
After the first test a reduction of lost steps (or better mm) from 0,8mm to 0,3mm can be found. - But this was a short test only.

What means the option "RotaryABC"? What does it change?

Do you have another idea what I can do?

EDIT:
after a few more tests..:
The problem occures ONLY when you work on curved lines, so when you test it on straight lines, also with high speed no problem occures.

Could some changes in microstepping help? Or do you have an another proposal?

Thanks


Michael
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Re: loosing steps in 3D only

Postby Support » 11 May 2016, 15:31

Please try this:
Set "Step delay" to 12us in settings
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Re: loosing steps in 3D only

Postby Brian » 12 May 2016, 13:49

I have had this problem myself. It appears only on arcs ( gcode with "i" and "j") sometimes small arcs like when engraving curved text but not circles. I was using Cambam to draw and generate gcode. The machine would stall and lose, sometimes, a half inch. Changing a Cambam setting to "convert all arcs to lines" solves the problem but generates loads of gcode. From what I can see it appears that acceleration and deceleration are not taken into account in arcs. I'd be interested to see if this helps or, maybe, opens another line of thought.

Brian.
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Re: loosing steps in 3D only

Postby JerryBurks » 13 May 2016, 14:51

The arcs issue may be another problem. The one I experienced with 3-d cuts (and I suppose user Zerspaner as well) was only linear moves as created by VcarvePro, no G2 or G3 moves.

I will give it a try with the step delay next time I have such a project.
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Re: loosing steps in 3D only

Postby Zerspaner » 17 May 2016, 16:34

Hi all,

I've made the first tests on my sample file "Kleeblatt" - which makes it a little more reproducable for me.

and.. surprise surprise - it works!
In the first tests I couldn't detect any lost steps.

What is behind this "step delay" value?

Jerry, have you done your test already?
Brian, could you also test with another "step delay" and with arcs? Would be interesting if this is a solution also for this.

Thanks and best regards


Zerspaner
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Re: loosing steps in 3D only

Postby JerryBurks » 22 May 2016, 04:14

Sorry, no test so far, just don't have a 3-D project right now.

But since yours was successful, that is some motivation to repeat the one that failed last time. Not this week but maybe next weekend.
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Re: loosing steps in 3D only

Postby JerryBurks » 22 May 2016, 18:07

Zerspaner, forgot to ask: which software version are you running? If that delay change helps I may try the newer version again.
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Re: loosing steps in 3D only

Postby Zerspaner » 25 May 2016, 04:04

Hi Jerry,

software is version
<VersionSW>2.10.1511.401</VersionSW>
(see also settings file above).
I'm very curious about your results.

BR

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Re: loosing steps in 3D only

Postby JerryBurks » 27 May 2016, 15:56

Aha, that is the one I am using as well.

I changed the step delay settings to 12us. I did not cut an extremely complicated 3D model yet but yesterday I made a pair of pistol grips that came out quite nice and without lost steps: https://lh3.googleusercontent.com/-EwgZIuIWsnaSltZGpix_re_kf77ZEEklY_6bN7A6-DzZ8MG5lOnoerQbpmjTYripmg5C-cJaA=w1920-h1080-no.
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Re: loosing steps in 3D only

Postby Zerspaner » 30 May 2016, 16:04

Dear Jerry,

looks great!

While during a few tests another strange problem occures.
Background: I have two steppers for x.

While milling this horse the "carving lines" mirrored (the program is ok).
I lost steps on both x-axis, approx. 1mm on one ande approx. 4mm on the other one.

I think this is not the same problem as before.. please see file
Attachments
Pferdekopf Forum.jpg
Pferdekopf Forum.jpg (64.36 KiB) Viewed 1349 times
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Re: loosing steps in 3D only

Postby Zerspaner » 12 Jun 2016, 08:13

Dears,

here a a few results after further testing:

1. There seems to be a power problem with USB ports, mainly with camera. So this maybe occours the mirroring of the "horsehead" and a few "system stops"

Is this possible that this comes from USB-power? For further testing USB camera off and I will try a powered USB-hub.

2. Loosing steps
It's much better with the settings from Andrej (step delay to 12µs). But still some lost steps detected on (Y) in most cases it has been X-axis.
What does the delay do? what are the advantages / disadvantages?

Thanks and best regards


Zerspaner
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Re: loosing steps in 3D only

Postby Support » 13 Jun 2016, 09:18

Do you use external power supply?
All devices that are connected so same root hub need to share bandwidth.
Never use any USB 1.0 devices connected to same root hub as controller.
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Re: loosing steps in 3D only

Postby Zerspaner » 13 Jun 2016, 12:40

Dear support,

yes I use external power supply for controller, but not for USB-hub (just ordered a active one).

Hm, I'm not sure if there are more than one contoller on the board of the laptop..

What means the step delay as I asked above?

Thanks and best regards

Zerspaner
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Re: loosing steps in 3D only

Postby Support » 16 Jun 2016, 07:34

DirStep Delay is delay between direction and step signal in microseconds.

So with recommended settings machine still looses steps? Also, toolpath as I understand gets at one point mirrored?
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Re: loosing steps in 3D only

Postby Zerspaner » 26 Jun 2016, 07:28

Dear Support,

thanks for your response.
Reducing the stepdelay makes it much better.
I think the mirroring is a separate problem.

In the next step I will try the new hub with external power supply. Hope this will solve the problem.

Thanks and best regards.

Michael
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Re: loosing steps in 3D only

Postby JerryBurks » 27 Jun 2016, 14:40

Just for the record....I have not had lost steps since I changed the delay to 12 us and I upgraded the software to the latest version (not sure if the latter has anything to do with it).
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