Sudden uphill battle with PETG?

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KaiborgStudios
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Sudden uphill battle with PETG?

Post by 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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ednisley
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Re: Sudden uphill battle with PETG?

Post by 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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insta
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Re: Sudden uphill battle with PETG?

Post by 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.
Custom 3D printing for you or your business -- quote [at] pingring.org

KaiborgStudios
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Joined: Mon Mar 21, 2016 2:18 am

Re: Sudden uphill battle with PETG?

Post by 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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ednisley
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Re: Sudden uphill battle with PETG?

Post by 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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insta
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Re: Sudden uphill battle with PETG?

Post by 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. ;)
Custom 3D printing for you or your business -- quote [at] pingring.org

KaiborgStudios
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Joined: Mon Mar 21, 2016 2:18 am

Re: Sudden uphill battle with PETG?

Post by KaiborgStudios » Sat Mar 17, 2018 11:05 am

Really appreciate the advice, new parts ordered!

ChrisERAU
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Joined: Thu Nov 12, 2015 1:23 am

Re: Sudden uphill battle with PETG?

Post by ChrisERAU » Fri Oct 16, 2020 8:52 pm

Sorry for resurrecting an old thread, but I'm experiencing the same problems as you. Did the new hotend solve the issue?

airscapes
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Re: Sudden uphill battle with PETG?

Post by airscapes » Tue Dec 01, 2020 5:04 am

funny, today I had my hot end stop printing after the first layer.. 2 times. It was my .5 nozzle hot end and had been used just the other day for several prints with eSun PETG. Seemed like the hot end is cooling off yet the thermistor says it is still 240. I swapped it out for the hot end that has the .75 nozzle and finished my print with no issue. I measured the resistance against one of the other hot ends after it was cool and both had very similar readings.. Wiggled the wire with no change on the meter. Will investigate later this week but seems odd.. I did find octoprint unresponsive from the console and I did reboot, not sure if I tried again after booting or just swapped out the hot end.
BTW the roll of black eSun PETG was wound very smoothly on the roll and diameter was 1.73 and 1.74 in some spots which seem as if they got some new equipment at the factory.. was thinking that this was the problem until I got the digital meat thermometer out and it read 138 when the hot end was reading 240. After swapping the working hot end thermometer and reading matched... Will let you know what I find

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