Extruder keeps slipping

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jimc
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Re: Extruder keeps slipping

Post by jimc » Sat Jul 05, 2014 3:30 pm

Terry it depends on which hot end your using. V3b requires hotter by 20 deg or so.

slamma
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Re: Extruder keeps slipping

Post by slamma » Tue Nov 18, 2014 9:12 am

Hey guys, I just wanted to come back here and post a follow-up for others. After struggling with the V3b extruder, I finally went back to the previous (V3?) ceramic hot end style extruder and my problems all vanished. I've been printing regularly for months without a single pop or click once I switched back.

As much as I like the V3b (I bought 2), I'm pretty confident it's a flawed design. There is simply too much mass on the V3b.

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insta
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Re: Extruder keeps slipping

Post by insta » Tue Nov 18, 2014 4:33 pm

:/ that doesn't make any sense. I also had good luck with the ceramic hotends, but I had good luck with the V3Bs as well...

The mass differential between the aluminum heater block and the ceramic has got to be inconsequential between the two designs, and the internals are the same.
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jimc
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Re: Extruder keeps slipping

Post by jimc » Tue Nov 18, 2014 5:00 pm

Yes they are the same hot end just with a different heater. not to mention that 99% of all the printers on the market right now use a heater block just like the v3b with the same 40w cartridge. Its a good proven design.

jsc
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Re: Extruder keeps slipping

Post by jsc » Tue Nov 18, 2014 8:13 pm

If the v3 works and not the v3b, that suggests that it may be a temperature issue. Did you bump the temperatures up by 20C for the v3b? It was the last thing jimc suggested.

Also, can you slide a piece of filament through the entire stack when dismounted, by hand? If not, perhaps a good cleaning is in order.

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Capt. John
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Re: Extruder keeps slipping

Post by Capt. John » Tue Nov 18, 2014 10:35 pm

v3b is not a flawed design. Printed 100s of models with no issues to speak of.
Does extruder drive hole line up into the v3b where there's a clear path?
Are you using the same extruder drive with both hotends?

Not the sharpest tool in this shed, but know the v3b has done me right.
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davycroc
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Re: Extruder keeps slipping

Post by davycroc » Wed Nov 19, 2014 1:07 am

I regularly swap between the ceramic heater and the v2b hotends.
185C on the ceramic is about 210C on the v3b due to the temperature gradient (acking previous post!)

If anyone else runs into this issue (extruder skipping):
1. Remove variables like the PEET tube, spool, use known good filament, etc.
2. Heat the nozzle to temperature.
3. Purge the nozzle with 10mm of filament at a good speed (100mm/min) and listen for the chunka-chunka of the stepper motor skipping.
4. No noise? Start your print.
5. It's skipping? Clean the nozzle.
6. Still skipping? Increase the nozzle temperature by 5C and try the purge again.
7. Still skipping? Adjust the tension on the idler bearing (1/2 turn at a time), try the purge again.

You can repeat 6&7 until the skipping goes away. Using small changes, you will see the skipping happening later in the purge (as chamber pressure builds up), or earlier (or more often). Use the feedback to continue fine-tuning the variables until everything works.

Now that you have it working:
Pinch the filament next to the top of the extruder block and purge it again. If it skips, keep tuning. When it is properly tuned, it will grab and feed the filament hard enough to pinch your skin between the filament and the extruder block. Don't bleed on your printer, and nozzle tattoo-burns are so not cool.

pjdevor
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Re: Extruder keeps slipping

Post by pjdevor » Sat Apr 04, 2015 5:08 pm

I'm also at a loss for what to do here. I've printed for 6 months fairly heavily, multiple objects, multiple filaments, etc. When the extrusion started producing thin/weak extrusion. I thought it was the hot-end, so ordered a replacement and still persists. After further troubleshooting, I removed the extruder block and cleaned it well, did the tests that MG video suggests, and I still have same issue. I've removed the hot-end, and tried to feed the filament through and it just slips, goes nowhere. With force, it can come through but it is not "gripping" like it did when new. I've adjusted the M4 idle screw in all directions to no avail. I'm convinced that the alignment has worn-out from the amount of filament and friction and the gear and idle pulley can no longer create enough contact to pull the filament through. I've send MG another email with this suggestion. I'm OK with replacing parts, but think it should last longer than 6 months before becoming non-usable. I would like to hear a simple solution, but changing the temps and firmware should have no impact on this. I believe its a mechanical issue that has prevailed over time, due to usage. Any other thoughts on this issue of slippage? or lack of filament pushing through?

Patrick

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jimc
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Re: Extruder keeps slipping

Post by jimc » Sat Apr 04, 2015 6:37 pm

well the bearing wont wear out. the drive gear teeth should still bite into the filament and make obvious marks in it. there is really nothing there to wear except the hole for the filament path. this would just get bigger over time and cause the filament to glide through the filament drive easier. is the drive gear spinning? is the shaft on the extruder motor spinning and the drive dear slipping on the shaft? do you hear noise from the extruder motor, clicking? did you take the extruder motor gearbox apart and look at the pinion gear? are the teeth worn out?

Dale Reed
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Re: Extruder keeps slipping

Post by Dale Reed » Sat Apr 04, 2015 8:14 pm

Perhaps the pinion gear in the stepper gearbox has worn out. In this case, the skipping is actually internal to the gearbox, and is not the drive gear losing grip on the filament.

Here's a way to verify that. Take the fans off the front of the extruder so you can watch the rotation of the drive gear. Heat the hot end to about 210 and try to feed and jog-extrude some PLA. Watch the drive gear as it tries to push. If the drive gear rotates consistently while you hear the skipping, the drive gear is not biting into the filament, the hot end is clogged, etc. If the drive gear itself is not rotating at a consistent speed while you jog, either the drive gear is loose on the shaft of the stepper gearbox (and you'll be able to see this, because you can see the D-shaped end of the shaft), or, if the shaft is not rotating at a consistent speed, the pinion gear inside the gearbox is worn out.

If your FFF profile has retraction enabled for most of the stuff you print, the constant reversals in extrusion can quicken the wear on the gearbox. Others have run into this, and you can contact MakerGear support for how to proceed to get the stepper/gearbox/whatever replaced.

BTW, only leave the hot end hot long enough to verify the problem! And don't do what I do, which is put the M3 hex driver through the fan with the fan running! (I have a little cemetery for fans I've destroyed this way!)

Hope this helps you find what's happening...
Dale

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