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Topic: How did this happen?

I came in to check on my print, the print head was about 10MM above the printed service and nothing was coming out. See the picture for the jam. I have no idea how this could happen, does anybody else? Any thoughts on how to prevent it from happening again. After disassembly, cleaning and reassembly all seem to be good so far...

TiM

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2

Re: How did this happen?

Filament got too hot near the drive wheel.

3

Re: How did this happen?

ronsii wrote:

Filament got too hot near the drive wheel.

I had the same issue. Whats the lowest extruder temp that we can use? I don't think the reported  temp reading are that accurate.

SD3, E3D hotend,linear bearing on x/y axis',pillow block bearing on y conneting rod, ball bearngs on front y axis, fan on y stepper motor.

4

Re: How did this happen?

This can happen if the extruder fan stops working.  The heat from the motor softens the filament as it goes over the top, and also from the face of the motor and the gear.  If the fan is working,m maybe the extruder motor is getting too much voltage from the motor driver.  There is a section on the driver voltage at the troubleshooting page on the Solidoodle website.

5

Re: How did this happen?

It started happening again, I cleared the problem. This time I noticed the feed gear was grinding. I loosened the feed tension and it seems to have solved it. We'll see. I'm extruding with a setpoint  of 200C. This was the default setpoint and I haven't played with it at all. I did have to remove the tensioning arm to change colors. It's looking like over tightening the tension arm is the culprit.  Does this make sense?

TiM

6

Re: How did this happen?

It happened for a third time. I loosened the pinch roller and reduced the extrude temperature to 190 and it still happened. I flipped the unit around and checked the voltages. How close should they be? The extruder voltage was only off by 1.3 milli volts, and it was low. I'm assuming this can't be the cause of the fillament over heating in the jigsaw?

TiM

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Re: How did this happen?

This has happened to me also numerous times. It started happening when I got a New hotend after the first one failed.For the first 2 weeks all was well.

SD3, E3D hotend,linear bearing on x/y axis',pillow block bearing on y conneting rod, ball bearngs on front y axis, fan on y stepper motor.

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Re: How did this happen?

It's consistently failing now. I wonder if I have a partial clog? It seems to extrude OK for awhile, but it seems to start skipping sooner and sooner. I've tried higher extruder temperatures, I've tried lower extruder temperatures. So far it's a no go. I guess it's off to the music store for a violin E-string...
The part that has me boggled is everything has been working fine for about a month.

TiM

9

Re: How did this happen?

How long has the filament been on back of the printer. Mine seem to start doing that after a couple of weeks

10

Re: How did this happen?

Filament goes bad? I had that same issue.

SD3, E3D hotend,linear bearing on x/y axis',pillow block bearing on y conneting rod, ball bearngs on front y axis, fan on y stepper motor.

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Re: How did this happen?

It will absorb moisture slowly over time.

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Re: How did this happen?

lawsy wrote:

It will absorb moisture slowly over time.

What is the effect of this happening (besides the one discussed)?

13

Re: How did this happen?

Grr, I can't print anymore. I've tried three different spools of filament and all three had the same problem. I swapped out the hot end, that didn't help. On a side note, the new hot end from SD had a different connector on the heater connection. After struggling for 5 minutes with the too short wires trying to get it to engage I compared it to the old one. The connector had two ears opposite the guide key that the old one didn't have. Snipped them off and it snapped right in. Of course after tuning the PIDs I started a simple print, about 20 minutes into it the filament was stripping and there was no feed. So it's not a clog. I guess the next step is to bake some filament in the oven and see what that does? Any suggestion would be greatly appreciated at this point.

TiM

14

Re: How did this happen?

One more thing I forgot to mention. I decided to check the extruder calibration as a possible culprit. At the end of the 100mm extrusion and the motor turned off, the back pressure on the filament was enough to reverse the extruder and back out about 4 to 8mm of filament. I'm pretty sure this isn't normal behaviour. Could it be caused by moisture in the filament generating steam, which causes the back pressure? Living in Southern California I didn't think I had to worry about humidity. Where are the Santa Anna winds when you need them.

TiM

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Re: How did this happen?

I think the filament over cured. to fix mine I put  the reels in a oven for 2 hours at 195 degrees Fahrenheit. They worked great after that. the plastic reels warped some but I could still use them with outside spacers.

16

Re: How did this happen?

Hi,

mr_tim34 have you checked the fan as Ian suggested?

This is what happened to me to when my fan stopped working.

17 (edited by saymo606 2013-04-23 10:03:09)

Re: How did this happen?

I started a simple print, about 20 minutes into it the filament was stripping and there was no feed. So it's not a clog

Hmmm from that I would say you DO have a clog!if classic sign! If the drive on the extruded motor turns but the bearing wheel doesn't and there is no feed into the hot end then its a clog IMO. It cant feed any filament in cos there is a clog, hence the stripping

18

Re: How did this happen?

It seems like a clog, but swapping in a whole new hotend didn't make any difference. It's fine for a bit, then it starts skipping and no plastic coming out. I've been printing with these spools for a month with no problems. Natural, blue and black. It started with the blue, I switched to black, same problem. I switched to the natural as I've printed with it the most, same thing. I baked it at 195F for a  couple hours this morning and still the same thing. I run the extruder at 200C and always have. Any suggestions?

TiM

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Re: How did this happen?

I'm pretty sure the fan is running, I'll check it tonight. I checked  the voltage to the extruder and it was 1.3mv low and I didn't adjust it. I am running the bed at 95C and have an enclosure, could this be a contributing factor?

TiM

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Re: How did this happen?

can u push it thru by hand?

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Re: How did this happen?

Yes, I can push it by hand, but I have to push pretty hard to get it through. I don't know if you saw the part about the backpressure. after extruding 100mm the filament will  back up 4 or 5mm due to the pressure inside the hotend forcing the extruder drive wheel to reverse.

TiM

TiM

22

Re: How did this happen?

Slow down the extruder max speed.

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Re: How did this happen?

Yes, the extruder fan is running, and what would be a reasonable extruder speed to try?

TiM

24

Re: How did this happen?

cut what you got by 25%

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Re: How did this happen?

pcpoirier wrote:

cut what you got by 25%

I am having similar issues, do you mean extrusion multiplier in slic3r?

SD3, E3D hotend,linear bearing on x/y axis',pillow block bearing on y conneting rod, ball bearngs on front y axis, fan on y stepper motor.