Extruder problems, advice wanted.
Posted by Myndale
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Extruder problems, advice wanted. March 05, 2011 12:00AM |
Registered: 13 years ago Posts: 87 |
Hi guys,
I managed to do a test of my extruder this morning. Very promising results for a first attempt but I have a few concerns:
First of all, it occasionally seems to smoke a little when it starts extruding, is that normal or an indication that the nozzle is running too hot? It also doesn't stop for a few seconds after I halt the stepper, is it supposed to? Or is that again an indication that it's too molten and hence the temperature is too high?
Secondly, it has a tendency to bunch up around the nozzle. I suspect that during an actual print the plastic will effectively pull itself out of the nozzle and prevent this, but could it indicate that the extruder gearing isn't gripping the plastic properly?
Here's my blog with photos and video, any and all help and advice muchly appreciated etc:
[www.ppl-pilot.com]
Myndale
I managed to do a test of my extruder this morning. Very promising results for a first attempt but I have a few concerns:
First of all, it occasionally seems to smoke a little when it starts extruding, is that normal or an indication that the nozzle is running too hot? It also doesn't stop for a few seconds after I halt the stepper, is it supposed to? Or is that again an indication that it's too molten and hence the temperature is too high?
Secondly, it has a tendency to bunch up around the nozzle. I suspect that during an actual print the plastic will effectively pull itself out of the nozzle and prevent this, but could it indicate that the extruder gearing isn't gripping the plastic properly?
Here's my blog with photos and video, any and all help and advice muchly appreciated etc:
[www.ppl-pilot.com]
Myndale
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Re: Extruder problems, advice wanted. March 05, 2011 04:06AM |
Admin Registered: 17 years ago Posts: 7,879 |
Myndale Wrote:
-------------------------------------------------------
> Hi guys,
>
> I managed to do a test of my extruder this
> morning. Very promising results for a first
> attempt but I have a few concerns:
>
> First of all, it occasionally seems to smoke a
> little when it starts extruding, is that normal or
> an indication that the nozzle is running too hot?
> It also doesn't stop for a few seconds after I
> halt the stepper, is it supposed to? Or is that
> again an indication that it's too molten and hence
> the temperature is too high?
Yes 250C is a bit too hot. I extrude the PLA I got from Vik at 190 and for 4043D PLA from Makerbot I use 220. For the first layer I use 20C higher to make it stick and that does tend to to bunch up if I extrude it into mid air.
The "smoke" could well be steam. If you live in a humid place the PLA will absorb some moisture. That also increases how much it oozes. You need fast reversal to stop it.
>
> Secondly, it has a tendency to bunch up around the
> nozzle. I suspect that during an actual print the
> plastic will effectively pull itself out of the
> nozzle and prevent this, but could it indicate
> that the extruder gearing isn't gripping the
> plastic properly?
I think it bunches because it is too liquid when it exits the nozzle to form a filament so it hangs around as a drop until it sets.
>
> Here's my blog with photos and video, any and all
> help and advice muchly appreciated etc:
>
> [www.ppl-pilot.com]
>
> Myndale
[www.hydraraptor.blogspot.com]
-------------------------------------------------------
> Hi guys,
>
> I managed to do a test of my extruder this
> morning. Very promising results for a first
> attempt but I have a few concerns:
>
> First of all, it occasionally seems to smoke a
> little when it starts extruding, is that normal or
> an indication that the nozzle is running too hot?
> It also doesn't stop for a few seconds after I
> halt the stepper, is it supposed to? Or is that
> again an indication that it's too molten and hence
> the temperature is too high?
Yes 250C is a bit too hot. I extrude the PLA I got from Vik at 190 and for 4043D PLA from Makerbot I use 220. For the first layer I use 20C higher to make it stick and that does tend to to bunch up if I extrude it into mid air.
The "smoke" could well be steam. If you live in a humid place the PLA will absorb some moisture. That also increases how much it oozes. You need fast reversal to stop it.
>
> Secondly, it has a tendency to bunch up around the
> nozzle. I suspect that during an actual print the
> plastic will effectively pull itself out of the
> nozzle and prevent this, but could it indicate
> that the extruder gearing isn't gripping the
> plastic properly?
I think it bunches because it is too liquid when it exits the nozzle to form a filament so it hangs around as a drop until it sets.
>
> Here's my blog with photos and video, any and all
> help and advice muchly appreciated etc:
>
> [www.ppl-pilot.com]
>
> Myndale
[www.hydraraptor.blogspot.com]
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Re: Extruder problems, advice wanted. March 06, 2011 07:53AM |
Registered: 13 years ago Posts: 87 |
Thanks again nophead. Lowering the temperature seems to have stopped it bunching up, although it still seems to curl up shortly after exiting the nozzle regardless of what temperature I extrude at. If I give it something else to stick to then it extrudes out fine, I did some line tests today and it seems to print nicely onto painters tape at 220 degrees.
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