sarkis.e
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Filament delay at start of print

Aug 21, 2018 1:46 am

The printer goes through the initial calibration, does the first wipe of filament at the front of the bed (which comes out just fine), then when it starts to print the 1-width skirt, it takes a couple of inches before the filament actually starts coming out. Then the first little bit that comes out kind of dots on the bed, then a full line of filament comes out.

After that, everything works just fine.

Any ideas what could be causing this?

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bobstro
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Re: Filament delay at start of print

Aug 21, 2018 2:00 am

In reality, that's why the skirt is used. It's meant to ensure you have a good steady flow before starting the print proper. If it's not causing problems on your actual prints, I wouldn't worry about it unless you're also having other inconsistent extrusion. It is possible you have a partial clog or some other problem.

If you want to delve into it, all of those things you describe are under control of the gcode generated by your slicer. Mine does not do the skips on the skirt. When I've got my 1st layer set properly, it prints a solid purge line (I have mine tweaked to start with a thick blob to catch dangling filament, then a narrow strip, a thicker strip and finally a 5mm run of 0 extrusion) them moves to print one continuous skirt line that adheres perfectly to the bed. Well, most of the time.

You can compare the gcode produced by various slicers to see if there are any observable difference. Gcode files are plain text so you can open them up in a text editor to see what's going on.

sarkis.e
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Re: Filament delay at start of print

Aug 21, 2018 1:39 pm

Thanks for the reply.

95% of the time it's not a problem. The other 5%, the drips don't stick and sometimes get in the way causing a snowball effect. I can live with that, I'm usually able to manually get them out of the way when it happens. As far as I can tell, the rest of the prints are fine.

I might try messing around with that initial purge line. Right now it's whatever the default Slic3r Prusa MMU settings are.

Thanks!

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richard.l
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Re: Filament delay at start of print

Aug 21, 2018 1:48 pm

It's this line in the Custome G-Code for the printer that causes the problem.

G1 E-4 F1000.0

You can try a smaller negative E or try removing it completely. I changed mine to

G1 E-1 F1000.0

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PJR
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Re: Filament delay at start of print

Aug 21, 2018 4:24 pm

richard.l wrote:
Aug 21, 2018 1:48 pm
It's this line in the Custome G-Code for the printer that causes the problem.

G1 E-4 F1000.0

You can try a smaller negative E or try removing it completely. I changed mine to

G1 E-1 F1000.0
I changed mine to:

G1 E-<DESTRING> F1000

Only problem is that I don't think that works in Slic3r :(

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

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bobstro
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Re: Filament delay at start of print

Aug 22, 2018 2:47 am

PJR wrote:
Aug 21, 2018 4:24 pm
[...] I changed mine to:

G1 E-<DESTRING> F1000

Only problem is that I don't think that works in Slic3r :(
Sadly, no. You can do some basic math and conditional tests though. I wish we could combine the best features of Slic3r and KISSlicer. Conditionals and user-defined variables in filament-specific settings would be so convenient. Perhaps a future update in one or the other?

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