Sudden uphill battle with PETG?

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Sudden uphill battle with PETG?

Postby KaiborgStudios » Wed Mar 14, 2018 7:06 am

Little bit of background info to start:

I've printed around 40 spools of ESUN PETG, and I believe I have a decent understanding of its characteristics and required settings. I print costume helmets for clients in pieces, and many of my prints are 24 hours plus. PETG has been a great filament for this purpose.

I use a slightly modified version JimC's settings.

M2 Rev. E V4

Over the last few months I've had more and more issues with PETG clogging mid print. I've slowly raised the temperature and lowered the speed. I'm now up to 260C and 40mm/m, just to get past the 3rd layer of the print. I know something must be wrong.

Things I've tried:
-Messing with tension.
-Printing a new ePC filament drive housing with less room for filament bunching above/below the drive gear.
-Opening up and greasing planetary gears.
-Torch heating nozzles
-Weldon #4 soaking nozzles
-Filament dust filter

I notice my filament drive stepper is running hotter than my x/y steppers, I can't remember whether or not that's normal.

I've ordered a few .35mm drill bits and I'm going to attempt to drill my nozzles out.

The only other thing I can imagine is an issue with the thermistor or heating cartridge? Is there any way to test their functionality with a multimeter?

Thanks!
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Re: Sudden uphill battle with PETG?

Postby ednisley » Wed Mar 14, 2018 12:16 pm

KaiborgStudios wrote:going to attempt to drill my nozzles out


At your level of production, consider nozzles as consumable items. Replace them, don't (try to) repair them, at least for the purposes of debugging failures.

I suggest swapping the entire hot end, rather than in-situ tweaking, to debug the problem. If the problem follows the hot end, then swap nozzles / liners / whatever on the known-bad hot end until the problem goes away. If the problem doesn't go away with a known-good hot end, then you know it's a feeding problem.

The symptoms indicate a mechanical problem, so start by verifying the filament feed path. Check for:
  • Worn support
  • Impacted fuzz in the guide tube
  • Round, unobstructed 2 mm hole through filament drive
  • Plastic fragments blocking the drive gear
  • Loose drive gear screw

Basically, make sure the filament feeds smoothly and easily by hand, install a known-good hot end, return the temperature & speed to the previous levels, then see what happens.
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Re: Sudden uphill battle with PETG?

Postby insta » Wed Mar 14, 2018 4:08 pm

Seconding consider it consumable. That's why you can buy nozzles by themselves :)

For reference, I have 6x M2s, about 600 hours a month of printing -- and I keep 8 SPARE v4 hotends, and 16 nozzles of different sizes (about 60/30/10 0.35/0.5/misc). Most of the nozzles are blowtorched and ultrasonicly cleaned, but I generally buy about 4 new ones every time I order parts from MakerGear and discard the least-goodest ones. When I get a jam, or excessive hairs, the nozzle comes off immediately and a new one replaced, and then it's post-mortem cleaned and refurbished then put back into the spares drawer.

I also have full spare heatbeds (2x extra), a spare RAMBo, a spare Z, spare linear rail carriages, spare belts. I don't run the printers full-time, but when I get print jobs, I need them all to work, and I need them all to work right then.
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Re: Sudden uphill battle with PETG?

Postby KaiborgStudios » Fri Mar 16, 2018 2:01 pm

Thanks for the info guys! I had no idea the nozzles had such a limited lifespan.

Regarding the hot end, can the physical hot end itself have any issues? Would swapping out just the thermistor/nozzle/heater cartridge have the same effect?

Checked the potential feed path issues, all seem ok.

Another question, would stainless nozzles be advantageous at all?

Thanks!
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Re: Sudden uphill battle with PETG?

Postby ednisley » Fri Mar 16, 2018 5:08 pm

KaiborgStudios wrote: Would swapping out just the thermistor/nozzle/heater cartridge have the same effect?


It depends on how much production time you're willing to squander on debugging.

If the intent is to make money printing parts, then swap in an entire known-good hot end, restart the part, and see if the situation has improved.

If you can debug the problem during normal downtime, then, sure, fiddle around with individual parts to decide what needs replacing.

Despite all that, you should have a thermistor on the shelf, if only because that's the most fragile part of the whole hot end, tends to fail unpredictably, and is trivially easy to replace. The symptoms will be erratic extruder temperatures, a MIN_TEMP shutdown, or a mysterious "heater failure" shutdown. No need to remove the hot end: just pull out the thermistor and slip in the new one.
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Re: Sudden uphill battle with PETG?

Postby insta » Fri Mar 16, 2018 8:55 pm

KaiborgStudios wrote:Thanks for the info guys! I had no idea the nozzles had such a limited lifespan.

Regarding the hot end, can the physical hot end itself have any issues? Would swapping out just the thermistor/nozzle/heater cartridge have the same effect?

Checked the potential feed path issues, all seem ok.

Another question, would stainless nozzles be advantageous at all?

Thanks!


You've run 100 pounds of PETG through a 0.01 inch hole at 480 degrees american, on a single $10 piece of brass. That's not a limited lifespan. ;)
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Re: Sudden uphill battle with PETG?

Postby KaiborgStudios » Sat Mar 17, 2018 11:05 am

Really appreciate the advice, new parts ordered!
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