[SpiderPig]

Hello to all,

I have a 6040 800W CNC mill and sometimes the X and Y axis skip steps. I've uploaded a video to YouTube so you can have a listen and you can also see it if you look closely. Here's the link : https://www.youtube.com/watch?v=J_sPRkuZTso

I've tried many different settings, in MACH 3 and in CamBam (which makes the GCode) with no success. I'm not sure weather the problems lies in the parallel port (the parallel port is built onto the motherboard), or with the power supply, the driver boards, or the settings in MACH 3.

I'm running Windows XP 32 bit. MACH 3 is the only software installed and I run my GCode from a USB stick.
Here's a few images of the settings in MACH 3;

Attachment 334178
Attachment 334180
Attachment 334182
Attachment 334184
Attachment 334186

If anyone has any ideas I'll be glad to have this problem behind me.

Thanks,
Matt

[snowyskiesau]

Your problem could be noise from the spindle,
Check that you have a good earth connection to the spindle. As supplied, most of the 6040 machines don't have any earth connection.

[SpiderPig]

Your problem could be noise from the spindle,
Check that you have a good earth connection to the spindle. As supplied, most of the 6040 machines don't have any earth connection.

I'll check it out, thanks. But the problem is there even when the spindle is not running.

[109jb]

the parallel port is built onto the motherboard

Is this on a desktop PC or on a laptop?

[awerby]

See if it stops happening when you lower the acceleration on the axes that are faulting. Also, copy the G-code to your hard drive before running it; there are sometimes glitches introduced when running it directly off a thumb drive.

[SpiderPig]

Is this on a desktop PC or on a laptop?

It's a desktop PC, Pentium E5400 2.7Ghz Dual Core with 2Gb of RAM running Windows XP v2002 service pack 3.

See if it stops happening when you lower the acceleration on the axes that are faulting. Also, copy the G-code to your hard drive before running it; there are sometimes glitches introduced when running it directly off a thumb drive.

I lowered the acceleration to about 1 and it didn't help so I put it back up to 10. It seems to be missing steps worse today too, which is odd. I also am running the GCode from the hardrive now but it had no effect.

EDIT : I've also come across something about an ACPI driver that might need changing? Though I couldn't find it on my PC. Any one heard of this?

[A_Camera]

I think it is a mechanical issue. I think that either your screws are not aligned with the motor axis or something gets stuck now and then. I assume you don't push any keys or move the mouse when this is happening. I would also change the look ahead lines from 20 to 1 and increase the step pulse time to at least 5 or even 10 microseconds. 1 is just not a good value unless you really have a very fast and reliable parallel port card and very fast stepper controller and driver. If your machine has has the crappy blue card, or something similar with Toshiba chips and slow opto couplers then that value is totally bad, should be much higher.

It was a long time ago I used parallel printer port but remembering to hear the same occasional clonk when I had the blue card, before switching to USB, so if you can afford it, I'd advice you to do the same and upgrade your machine, even if you don't have the blue card but have decent drivers. Of course, try the other alternatives first, check alignments and change the settings, those cost nothing extra.

[SpiderPig]

I turned the look ahead lines down to 1, although it was slower, it didn't make a difference to the skipping steps. I put the step pulse time up to 10 and even the max of 25, which seemed to help a lot but it still skips every now and then. To test the driver boards I wrote some code for Arduino and plugged the boards into that and the motors ran perfectly at all manner of speeds and changes in direction which makes me think the problem is either in Mach3 or in the parallel port hardware / software. Tempted to try out a PCIe card with a parallel port and see if that works, or even just program the Arduino to run the G code.

How did you upgrade to USB? Is it a different board? Can Mach3 use a USB?

EDIT : Also, I'm using mm's as the units in Mach3. Not sure if it should make a difference or not...

[snowyskiesau]

There are (at least) 2 USB options for Mach3.
UC100 and Smoothstepper.
Mach3 has drivers for both.