1 Topic by byshop303 (edited by byshop303 2015-04-16 01:39:01)

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Topic: Extruder problems

Like many, I'm having problems getting the Press to consistently extrude. I've read through every thread that I could find on the topic on this board but the problem I'm seeing now seems to be slightly different from those I have read about so I'm posting a new topic. If this is something that was solved in a previous post, I apologize for creating another post on the topic.

The main issue I'm having with the press right now is that it seems like the filament isn't in alignment with the top of the hot head and it stopping when it reaches it. I've taken apart the entire hot head/block, acetone bathed it the heads and the block itself to get ABS off of the threads, manually unclogged it so I could blow through it, and re-assembled. It seems like the top of the hot head doesnlt align well enough with the hole and the filament is colliding with an edge and not melting. Attached is a photo of when I see after the "thumping" starts. No filament gets inside the hot head. I can push the filament through manually if I hold the heat block with some pliers.

Here's what I see when I take it apart: http://soliforum.com/i/?lQDJ4PY.jpg

What am I missing? Thanks in advance.

Edit: Wrong photo.

2 Reply by workwesty

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Re: Extruder problems

My partial answer is feed it from the right. Second adjust the gear to the left. That being said I tried all that and got mixed results.

3 Reply by scruffybob

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Re: Extruder problems

I think it may actually be a problem that others have seen.    When the Press gets hot, the filament can heat up BEFORE it goes into the extruder heat block, it softens up and jams right at that point.

On the new Press I received, the fan has been reversed from the original shipments, so that the extruder fan blows INTO the extruder.   This seems to keep the filament cool enough not to soften before it goes into the heat block.

4 Reply by byshop303 (edited by byshop303 2015-04-24 20:56:58)

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Re: Extruder problems

I've tried both of your suggestions but with no luck so far. I've adjusted the stepper gear multiple times and it appears to be as lined up as best I know how to do. I've tried feeding from the right but the result is the same. I've also tried reversing the fan since that's a pretty easy mod, but it didn't have any effect.

It actually kinda seems like the extruder is too cold if anything. I've been trying temps ranging from 210 to 260 but with no difference.

I've removed the block and head parts and dropped them in acetone again and I'll put it all back again tomorrow.

Thanks.

5 Reply by trayracing

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Re: Extruder problems

Is there a gap between your heater block and extruder body? Looks like they could be touching (but hard to tell), and that would overheat the bottom of the extruder & top of the heat break. You want the heat break tube in the heater block just far enough that the nozzle tightens on the heat break tube, not the block.

(Also, you want to snug up the nozzle when it's warm. Snug, not tight like a lug nut. smile )

6 Reply by trayracing

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Re: Extruder problems

As far as clues, also note in your photo that the filament slumped where it enters the heat break tube. This usually means the top of the heat break overheated. (Although if you opened the extruder for the photo while heater block was hot, that would do it.) You'd need to get rid of the thickened filament before you can extrude again.

7 Reply by byshop303 (edited by byshop303 2015-04-16 22:19:50)

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Re: Extruder problems

trayracing wrote:

Is there a gap between your heater block and extruder body? Looks like they could be touching (but hard to tell), and that would overheat the bottom of the extruder & top of the heat break. You want the heat break tube in the heater block just far enough that the nozzle tightens on the heat break tube, not the block.

(Also, you want to snug up the nozzle when it's warm. Snug, not tight like a lug nut. smile )

I think you're on the right track. I dismantled the whole thing, cleaned it and put it all back together. I think the problem I was seeing might have been related to the cables turning the heat block a bit from tension after the extruder gets hot. I think this was creating a small gap between the top hot end and the nozzle, which resulted in the top hot end not staying hot enough to soften the filament enough to push through. In retrospect, this might be related to a lot of the extruder jam issues I've seen. I gave the heater block a little twist to make sure it's tight after it heated up and the thing printed like a charm, although I noticed that the block twisted back a few degrees over the course of the print, presumably from the cable tugging it a bit as the head moved around the bed.

I printed this earlier today and I didn't get a single jam in the 2-3 hours it took to build:

http://soliforum.com/i/?2o1Najr.jpg

I'll keep you guys posted.

Edit: Then I gave him a "bath" and now he's all shiny:

http://soliforum.com/i/?kOU9FXu.jpg

8 Reply by byshop303 (edited by byshop303 2015-04-17 18:41:17)

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Re: Extruder problems

I had to dismantle and re-assemble the head one more time. With the heater block hot, I screwed the top end in to the desired height and angle, which would leave the heater block rotated a few degrees clockwise (looking down) from square with the rest of the assembly. Then I screwed the extruder nozzle into the plug tight. After attaching the whole thing back to the extruder, I turned the heater block counter clockwise a few degrees to tighten it and square it with the extruder assembly. Now the thing is printing like an absolute champ. Barring temp difference requirements for different types of thread (I have a few colors of translucent ABS that appear to need higher temps to melt) I haven't had a single stepper jam yet after hours and hours of printing. Honestly, this is the best I've seen the machine run since I got it.

Thanks everyone for the suggestions.

9 Reply by workwesty

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Re: Extruder problems

http://soliforum.com/i/?VFNfjtD.jpg
This is my temporary fix to my jamming problem. I guess I wasn't getting the friction I needed. Now my press is printing like a champ. I tried shifting the ridged spooler over for better contact but the seemed to torque the filament too much , I think. I hope the rubberband holds up to the heat.

Adam

10 Reply by workwesty

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Re: Extruder problems

I love my fix, I can print again!! The tension it puts on the bearing fixed the problem of the gear eating dinner he f iliament and fix the alignment problem I had when the f iliament enters the hotend.

11 Reply by madfalcon81

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Re: Extruder problems

I might have the same problem. So here is a question: you moved the small wheel closer to extruder gear (this means it presses harder on filament) or away from it ???

Fat kids are harder to kidnap!

12 Reply by workwesty (edited by workwesty 2015-04-24 13:08:59)

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Re: Extruder problems

Ok, it presses harder on the gear. This took awhile to figure  out because I thought my jamming problem was because the gear was eating the filament but really the filament was being eaten because it wasn't able to push hard enough. Also my last theory is that when it pushes hard it lines up the filament with the top of the hot end better. Still looking for a permanent fix. To test if this would help you just push down on the lever while printing to see if it helps.

Adam

13 Reply by madfalcon81

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Re: Extruder problems

Adam, does your extruder motor thumps ?

Fat kids are harder to kidnap!

14 Reply by workwesty

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Re: Extruder problems

Nope that is a connection problem or voltage issue.

15 Reply by mikebrown

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Re: Extruder problems

I have had a similar problem.  I thought the filament was not lining up properly with the input tube on the extruder head.

If you cannot get filament to feed, one thing to check is that top input tube.  It can become coated or blocked similar to the hot end extruder head.  The way to test this is to disassemble (unscrew the two thumb screws) the assembly and pull out the extruder head while the unit is cool.  Unscrew the top feed tube and then test that filament will pass through easily and smoothly. 

When it's blocked, your filament only goes in partially and will not pass through.  I found the best way to fix was to soak the input tube in acetone for 20 minutes, rinse off with water and then use a piece of filament or similar sized wire or allen wrench to clean out the debris.  Then hopefully the filament will now pass through the tube.  Worked for me.