This is a bit tricky to explain. I haven't had any awesome prints yet, but I'm getting closer daily. I have my extruding speed dialed in enough now that I was able to move forward enough to discover a new problem. This is on a Prusa with RAMPS and a makergear extruder.

I did 4 prints last night of the 40mm test cube. The first one got about 2cm high (Z) and then decided to move about 2cm toward my endstop (Y) and continue printing, mid air. I tried from a different computer, same result, but it happened sooner. On my last one, it finished the raft and about 2 layers high, it did it.

At first I thought maybe it was a pot set too high on the driver (Y) or maybe a communications problem? I'll try lowering the baud from 115200 tonight. Has anyone ever had this problem (and solved it?)
I'll post a video a little later.

Here is a picture:
[picasaweb.google.com]

And one more:
[picasaweb.google.com]

Edit: No, the belt isn't slipping or skipping, this isn't a mechanical issue, I paid very close attention to the belt when I did this.

Edited 1 time(s). Last edit at 04/01/2011 09:09AM by sharkcus.

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blog.burningriverlabs.com <-blog
www.burningriverlabs.com <- work
www.clevelandracing.com <-fun

The most common cause is the flow rate being a bit too high so as the layers build up the nozzle starts to plough through the plastic and that causes enough resistance to stall the stepper motor. Or the stepper current might be too low, rather than too high.

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[www.hydraraptor.blogspot.com]

[www.youtube.com]

I started the video right after it messed up, hopefully it makes sense after this.

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blog.burningriverlabs.com <-blog
www.burningriverlabs.com <- work
www.clevelandracing.com <-fun

You know, I can see a line where it "plowed" through on the cube, would that be enough to stall? Would I adjust the Z layer height for that or just work with flow?

But I did a 20mm "walls only" cube and it did the same thing, there would have been no resistance even if it plow through it.

You can kind of see it here:
[picasaweb.google.com]

The only reason you dont see the rest of the cube after the shift is because it was about 3cm above the bed and pla just went everywhere.

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blog.burningriverlabs.com <-blog
www.burningriverlabs.com <- work
www.clevelandracing.com <-fun

sharkcus Wrote:
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> You know, I can see a line where it "plowed"
> through on the cube, would that be enough to
> stall?

That depends on how much torque the motor gives and the current setting.

>Would I adjust the Z layer height for that
> or just work with flow?

You should set the flow rate to give the correct filament width on the thin walled box.

>
> But I did a 20mm "walls only" cube and it did the
> same thing, there would have been no resistance
> even if it plow through it.

Does the Y-axis move freely or does it bind? Perhaps the pulley is loose or the current too low. Grab it while is moving and feel how easy it is to stall. It should need significant force to stop it.

>
> You can kind of see it here:
> [picasaweb.google.com]
> /DropBox?authkey=Gv1sRgCKCqisT4m-m_igE#55904343924
> 08147394
>
> The only reason you dont see the rest of the cube
> after the shift is because it was about 3cm above
> the bed and pla just went everywhere.

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[www.hydraraptor.blogspot.com]

Thank you. I will go through all of your suggestions as soon as I get home (specifically grabbing the Y to see if it slips)

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_____________________________________________
blog.burningriverlabs.com <-blog
www.burningriverlabs.com <- work
www.clevelandracing.com <-fun