Extrude stops extruding (not jammed), consistent temp issues (m2)

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UnknownTarget
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Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by UnknownTarget » Mon May 21, 2018 1:08 am

Hey all,

So this has been driving me bonkers. I had everything dialed in, and then all of a sudden one of my print files started acting funny - it would print the first 50 or so layers fine, then above that it would barely extrude, leaving whispy towers of filament on top of the model.

So of course I checked - nozzle's clear. In fact, all I had to do was retract the filament, snip it, reinsert and it would be good to extrude again.

So, since it's a small thin part I thought that maybe the extruder was getting overworked by retracting and extruding all the time. So I disabled the retract - which made it worse! So I re-enabled it. Issue continued - first 50 layers or so, then no extrusion.

Then it started happening on all of my files. Now I can't print files that were fine just before.

I've also noticed that the cartridge has difficulty maintaining a consistent temperature - if I set it to 215, it goes up to 220, then down to 210 in a sine wave style pattern. It keeps overshooting and undershooting its target temperature. So, thinking that maybe the filament was getting soft and jamming up in the extruder motor, I dropped the target temperature to 205 so that it would only go up to 210 and down to like 190ish. Still no luck.

I've also noticed that the HBP is now cutting off its temperature returns at random intervals - sometimes it'll register, other times it will just show 0.

I've also tried cleaning the nozzle (it's fine), making sure the spool is free to rotate (it is).

Really hoping someone can help me solve these issues. This has been driving me nuts! Thanks!

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ednisley
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Re: Extrude stops extruding (not jammed), consistent temp issues

Post by ednisley » Mon May 21, 2018 1:06 pm

UnknownTarget wrote:
Mon May 21, 2018 1:08 am
the cartridge has difficulty maintaining a consistent temperature
The hot end thermistor is failing, so order a new thermistor (*) and install it.

While awaiting the package, restore all the settings to their previous values. There's no way to tweak around broken hardware.

It's that simple ...

(*) Order two, put one in your small box of M2 bits & pieces, and don't forget you have it. You will thank me later. [grin]

UnknownTarget
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Re: Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by UnknownTarget » Mon May 21, 2018 1:50 pm

I should have mentioned that I *just* put in a brand new thermistor AND a brand new cartridge.

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ednisley
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Re: Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by ednisley » Mon May 21, 2018 3:56 pm

Assuming the new thermistor is good, the failure will be in the cable between the thermistor and the RAMBo board. That's uncommon, but not rare.

With the hot end at operating temperature, wiggle-n-jiggle the entire length of the cable to locate the problem; when the temperature fluctuates, you've found the spot.

You could pull the thermistor cable out of the braid and look for the worn section, but sometimes the failure will be hidden from view inside the insulation.

A multimeter applied end-to-end on each wire (with both ends unplugged!) may help, although the test will be easier with three or four hands.

Good luck on the hunt ...

UnknownTarget
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Re: Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by UnknownTarget » Mon May 21, 2018 5:52 pm

Just to clarify, are we talking about the hbp or the hot end heating issue? I only replaced the thermistor in the hot end.

Also any ideas on the extrusion problem?

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ednisley
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Re: Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by ednisley » Tue May 22, 2018 1:05 am

UnknownTarget wrote:
Mon May 21, 2018 5:52 pm
are we talking about the hbp or the hot end heating issue?
I'm not sure anymore ... [sigh]

The initial "above that it would barely extrude" suggests an extruder problem.

The "extruder was getting overworked by retracting and extruding" could point to a filament drive problem.

The "happening on all of my files" rules out a model geometry problem and definitely points to a mechanical or electrical issue.

None of those will have anything to do with the platform heater, so that's where I started.

When you see "it goes up to 220, then down to 210 in a sine wave style pattern", then you should run a PID auto-tune operation. Search the forum for details; it's been covered recently. Remember to store the new PID parameters when you're done.

You reported installing a new thermistor and cartridge in the hot end, then only the thermistor. Either of those may be different enough from the previous ones to require a retuning the PID loop controlling the temperature.

The "HBP is now cutting off its temperature returns at random intervals" is entirely different and suggests a problem with either the platform thermistor or its cable to the RAMBo.

So, do this in order:

0. Restore all your slicing settings to whatever they were before this mess started

1. Run a PID auto-tune to fix the hot end oscillation

1a. If the hot end temperature varies abruptly, then it's a bad hot end thermistor or its cable

2. Disassemble the filament drive, check for worn plastic (non-round holes), remove accumulated crud & fuzz, verify drive gear tightness on drive shaft, verify filament track near middle of gear width. Reassemble, verify proper gear tooth indentations in filament.

3. Manually heat the platform, then apply cable wiggly-jiggly to find the thermistor cable break. Replace as needed.

3a. If the platform thermistor cable shows no problem, then you need a new platform thermistor. I don't know if they're available separately or if you're in for a whole new assembly.

Report back along the way, because you may find relevant evidence ...

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sthone
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Re: Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by sthone » Tue May 22, 2018 3:43 am

ednisley wrote:
Tue May 22, 2018 1:05 am
3a. If the platform thermistor cable shows no problem, then you need a new platform thermistor. I don't know if they're available separately or if you're in for a whole new assembly.
You can get these separate you just have to ask for them as they are not listed on the site. (they were about $15 last time I ordered)

Depending on the age of your M2 yours may have a connector at the build plate for the thermistor but the new ones come wired completely with a single connector that plugs right into the Rambo board so you have to redo the wire harness. (the one I was sent was why too short for my kit M2 so it might be a good idea to measure your wire length and let them know exactly what you need.
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jk42
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Re: Extrude stops extruding (not jammed), consistent temp issues (m2)

Post by jk42 » Tue May 22, 2018 5:35 pm

I would suggest contacting us at support@makergear.com.
We can help you trouble shoot what is going on.
A thermistor should never read 0°C. Shoot us an email
and we would be happy to assist you.
~Jason from MakerGear

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