Extruder keeps slipping

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jimc
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Re: Extruder keeps slipping

Post by jimc » Mon May 12, 2014 4:47 am

if you have gone all the way through to the point of replacing your hot end then you need to look at the gearbox. occasionally the pinion gear can become worn. just remove the small allen screws holding the planetary box together, look closely at the center gear then report back


problem is for both of you guys is there are quite a few things that can cause this and 95% of them are usually user error, dirty hotend, bad filament, etc. its almost always that stuff first before its a printer problem.

slamma
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Re: Extruder keeps slipping

Post by slamma » Mon May 12, 2014 6:13 am

I put a groove mount on my other 3D printer to try and debug this issue. I have mounted my M2 hot ends on my other printer as a test and then print fine. It's only when printing on my M2 that I have a problem.

Now that I know that the gearbox might have a problem. I'm going to look into that.

slamma
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Re: Extruder keeps slipping

Post by slamma » Mon May 12, 2014 8:05 am

I separated the planetary gearbox from the stepper and the gear that's mounted on the stepper shaft was worn down significantly. Each tooth of the gear was worn down to a sharp point and the diameter of the gear as a whole was reduced.

Does this necessarily mean it's the source of the problem though?

Thanks for that suggestion jimc, it was a good one.

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jimc
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Re: Extruder keeps slipping

Post by jimc » Mon May 12, 2014 12:24 pm

Yeah you need to send an email to rick or support. Im sure he can fix you up no problem

markb
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Re: Extruder keeps slipping

Post by markb » Mon May 12, 2014 1:55 pm

jimc wrote:if you have gone all the way through to the point of replacing your hot end then you need to look at the gearbox. occasionally the pinion gear can become worn. just remove the small allen screws holding the planetary box together, look closely at the center gear then report back


problem is for both of you guys is there are quite a few things that can cause this and 95% of them are usually user error, dirty hotend, bad filament, etc. its almost always that stuff first before its a printer problem.
This is great advice. How often do you end up cleaning out your hotend?
I know you are using good filament.

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jimc
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Re: Extruder keeps slipping

Post by jimc » Mon May 12, 2014 2:17 pm

mark, as for cleaning the nozzle and tube, that all depends. i have found that the more i switch plastic types the faster the tube will tighten up. it could be 2 weeks if i switch everyday or it could be 2mos or more. its not exactly routine maintenance. it will vary depending on the person. it can happen not just from changing plastic types either. for example i have one abs filament here in a few colors, very good quality stuff and i have no trouble with it except for the silver. if that sits idle in the extruder for maybe just 10 min its all over with. something about it, i assume the metallic colorant, makes it turn dark brown and harden like a rock. that is an unusual filament and not the norm but it is what happens over a very long period of time if plastic is left to sit idle in a heated hotend. just look at the crusty crap that builds on the outside of the nozzle. it turns black and hardens. i personally dont have an issue with that so much though as i do with switching plastics. in a sense the same thing is happening because some of the plastics dont intermix well and a coating of the previous plastic is in the tube and doesnt get pushed out so it hardens. switch plastics again and it does it again and so on until the tube gets tight. i pulled a piece of plastic out of my tube recently that when sliced you could see the rainbow of layers.

b8smat
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Re: Extruder keeps slipping

Post by b8smat » Tue May 13, 2014 2:50 pm

To update my original problem - the fix of reducing the flow to 90% produced two flawless 7 hour prints but only with the layer height set to 0.1mm. Increasing to 0.2mm resulted in the same problem, so maybe 90% is still too much flow for my current level of "clogness". I guess I'll buy some 0.35mm drill bits to see if I can clean the head.

Of course there is a vicious circle in this, failed prints where the filament stops feeding is precisely what causes plastic to get overheated in the hot end and cause clogging.

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Re: Extruder keeps slipping

Post by jimc » Tue May 13, 2014 2:57 pm

I have never actually had a vlog in the nozzle itself. Its the brass tube that gets tight.

slamma
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Re: Extruder keeps slipping

Post by slamma » Thu May 15, 2014 12:57 am

I have worked with the good people at MarkerGear to get this pinion gear replaced on my machine. Once I receive and test it, I will report back if it successfully resolved my issue or if I'm still in the hunt for a solution. Thanks for the help guys.

slamma
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Re: Extruder keeps slipping

Post by slamma » Thu May 22, 2014 6:49 pm

After replacing the pinion gear, I had some time to investigate this some more. I'm at a bit of a loss because replacing the pinion gear didn't appear to improve the situation.

Basically, when I have the hot end up to temperature and remove the filament drive, I can push the filament through the hot end by hand and it goes quite easily. When I put it back together and use the stepper to drive extrusion, it yields and clicks immediately like is shown in the video at the top of this thread.

In the process of replacing the pinion the stepper was also replaced. Additionally, I inspected the gearbox and it was very smooth and appeared to be in good working order.

Additionally, I boosted the extruder current to the maximum via a gcode command and put a heat sink on the extruder stepper controller chip and boosted the airflow over the controller board. This didn't affect the clicking behavior.

The thing that is strange to me is that when this M2 was new, it seemed to be able to exert much more force onto pushing the filament through the hot end. It never clicked in the first 6 to 9 months of owning it. Now anytime it tries to extrude the filament it clicks. Despite anything I try to do, it just seems unable to develop any amount of force now.

Maybe I should try to extrude using the unused E1 stepper driver on the rambo board. One of the only things left to investigate seems to be that perhaps the E0 stepper driver on my controller board is degraded somehow and unable to develop drive current.

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