Printer extrudes filament off the plate before printing..

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Spencer
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Printer extrudes filament off the plate before printing..

Post by Spencer » Mon Feb 15, 2016 6:59 am

Before each print the printer moves from the left, all the way to the right, extrudes filament completely off the plate for about 5 seconds, and then goes off to print. No idea why this is happening :( Any ideas?

Vandal968
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Re: Printer extrudes filament off the plate before printing.

Post by Vandal968 » Mon Feb 15, 2016 8:10 am

The printer does it so that your print will succeed. During the relatively slow warm up time the filament above the hot end softens from sitting in the warm air rising from the hot end. It purges off the side so that there is no back pressure and it can easily feed the softened filament and clear it out. The printer can feed filament faster than it heat soaks, so after the purge it can lay down the first layer (high back pressure) without the feed pinion stripping softened filament since the soft stuff has already been purged.

Hth,
C

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PcS
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Location: Michigan

Re: Printer extrudes filament off the plate before printing.

Post by PcS » Mon Feb 15, 2016 1:28 pm

This is in your g-code start up script. It is to prime the nozzle and wipe the string off in an effort to ensure a good solid clean line at print start. You can remove this if you wish , but if you do, at least use a skirt of one layer and 3 lines around your print to get it primed before it starts your first layer.

Spencer
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Re: Printer extrudes filament off the plate before printing.

Post by Spencer » Mon Feb 15, 2016 2:56 pm

Ah! Okay that makes total sense. So do you guys have a little bucket to catch it in?

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Jules
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Re: Printer extrudes filament off the plate before printing.

Post by Jules » Mon Feb 15, 2016 2:59 pm

Spencer wrote:Ah! Okay that makes total sense. So do you guys have a little bucket to catch it in?
Tweezers. :lol:

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Matt_Sharkey
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Re: Printer extrudes filament off the plate before printing.

Post by Matt_Sharkey » Mon Feb 15, 2016 3:02 pm

My students always freak out when they see the little loop of plastic hanging off the edge. I just explain that they're boogers.

and then I throw it at them.

some days are slow at work.

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Jules
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Re: Printer extrudes filament off the plate before printing.

Post by Jules » Mon Feb 15, 2016 3:09 pm

Matt_Sharkey wrote:.....and then I throw it at them.

some days are slow at work.
:lol: :lol: :lol:

Spencer
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Re: Printer extrudes filament off the plate before printing.

Post by Spencer » Mon Feb 15, 2016 3:47 pm

Haha I got kind of concerned because it drops right next to the fan of the motherboard..

Spencer
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Re: Printer extrudes filament off the plate before printing.

Post by Spencer » Mon Feb 15, 2016 3:54 pm

Wait, so is this way the first few inches of the filament sometimes comes out at a 45 degree angle from the nozzle at first? But after a few inches it flows straight down?

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Jules
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Re: Printer extrudes filament off the plate before printing.

Post by Jules » Mon Feb 15, 2016 5:53 pm

Spencer wrote:Wait, so is this way the first few inches of the filament sometimes comes out at a 45 degree angle from the nozzle at first? But after a few inches it flows straight down?
The 45 degrees? Tiny bit of cold unmelted leftover filament on the tip of the nozzle that eventually melts. If you clean the tip every time when it's done that won't happen. Not a big deal though either way - it does melt eventually and fall off. (But yeah, that's one of the reasons for the purge off the side, to get things flowing evenly before printing.) :D

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