Strange stepping issue

I have a Sells Mendel running Gen6

I used to run it off an old desktop just fine using Repsnapper, when that died I switched to running it off a netbook and that is when this issue started.

About 60% of my prints now step over after a few layers mostly on the Y axis but sometimes on the X axis too. Often they step back after about 6-10 layers leaving a ridge on the print.

I changed back to running off a different desktop and tried printing a box the Y axis printed about 5 layers perfect then started stepping over, this time it never came back.

Is this likely to be a motor issue or an electronics issue, I have a spare Sanguino board that I have been making to run a SD card is this likely to fix my stepping issue as I am at a total loss as to whats causing it.

Gary

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Experimenting in 3D in New Zealand

Anyone? I'm kinda getting desperate as I can no longer rely on my printer to make decent prints and I'm not sure what my next step should be

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Experimenting in 3D in New Zealand

Could it be your USB messing up the connection?
Try using a different computer. From your description it seems all that has changed is your computer, and the weak link there is the USB connection.

Your missing steps, it's either a mechanical issue, i.e. one of your axis takes more force to move than the steppers are providing.
Lubricate the axis, if that doesn't fix it try turning the pots on the stepper drivers up very slightly, and by slightly I mean as little as you physically can.

It could also be an electrical issue
Loose connection
Electrical noise
or any number of other things, but I'd start by assuming it's mechanical.

Justin Andrews Wrote:
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> Could it be your USB messing up the connection?
> Try using a different computer. From your
> description it seems all that has changed is your
> computer, and the weak link there is the USB
> connection.


Yes the original computer died and this issue is now happening on 2 different ones, I'm looking around for a shielded cable I know I have one somewhere

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Experimenting in 3D in New Zealand

Assuming that you've already checked for a mechanical problem ...

Could it be a power-saving feature powering down the USB after a few minutes?

Hmm could be I do remember disabling that on the original desktop and the screensaver. I have done the screensaver on this new computer but forgot about the power saving function on ports will have to have a look

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Experimenting in 3D in New Zealand

Nope not a power down issue, and not a heat issue either as had a desk fan blowing on the Gen6 today and it still stepped on layer 4 damn annoying and mechanically everything is fine, so time to finish the sanguino board

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Experimenting in 3D in New Zealand

It looks like a power surge due to switching of a the lamp load. Try with a ferrite torus in both your USB and power supply cables. Two turns of cable through the torus is better than just going through.

misan Wrote:
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> It looks like a power surge due to switching of a
> the lamp load. Try with a ferrite torus in both
> your USB and power supply cables. Two turns of
> cable through the torus is better than just going
> through.

Any idea where I can get some?

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Experimenting in 3D in New Zealand

Some USB cables do have it built in (these bulges [www.computeractive.co.uk] ). Some electronic equipment may have it too. You can get them on eBay and I guess on RadioShack too.

After much thinking I realised the freezer is on the same circuit, but haven't had time to see if it is what's causing the issue

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Experimenting in 3D in New Zealand

Have you tried printing from SD? I know, "bbbbut... it's not convenient"...I get it. But have you tried it that way? If you are having issues with the communications, then that should resolve it.

Since it would be resolved under those circumstances, then you would have a pretty good assurance the issue IS communications rather than something other mechanical or electrical issue directly associated with the printer itself, leading to better understanding than stumbling about blindly in the dark groping for something that may or may not even be the issue.

Not yet because my only SD capable card is finished yet

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Experimenting in 3D in New Zealand

The step signals are generated by the microprocessor, so USB communications would not be a likely culprit, unless you are using Win7 64-Bit.

You can evaluate your machines tendency to skip steps by loading each axis up with some weight, and observing how it runs. On the y axis you can stack books or magazines until it stalls. If the problem is too little current, or binding, it will turn up right away. If the problem is over current/over temp protection kicking in on the drivers, it may take a while moving for the problem to show.

Thanks will have a try at the weekend, using XP 32bit

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Experimenting in 3D in New Zealand