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Bogwopit
(@bogwopit)
New Member
Wits end

I have been trying to fix this using all the guides available, but I just can't seem to nail the issues.

It all started after having a major blockage that was the result of a print fail. I cleaned everything out, shouldn't have been a problem but it hasn't been right since. I have 2 problems that I believe are connected, but right now I have no idea.

1. As I bring the hot end up to temperature, it begins to extrude. The motor isn't moving, it's just... extruding. As you can see in the photo here, this has just finished coming up to temperature. This seems to start kicking in at around 195 degrees and just gets worse as you up the temp. After a while it runs out of material and stops extruding but as soon as you advance the motor it starts again.

2. When the motor does extrude when I've been performing tests it will do various different curls rather than just coming down straight. Sometimes corkscrew, sometimes it does what's in the photo. Either way, I know it's not supposed to do that.

All the guides I've seen basically trace it back to an unclean nozzle or hot end. Well, I've done lots of cold pulls, I've had the nozzle in isopropanol to get all the PLA out then cleaned it, I've used acupuncture needles, I've even replaced the PTFE tube and tried with different brand new nozzles but None of it has made a difference. I'm really at my wit's end and I don't know what else to try. The quality of the prints is massively effected, and I can't print in detail without the print failing, which is a problem because I got the printer to do fine detail D&D scenery printing.

Any help is really appreciated

Posted : 26/03/2019 5:28 pm
holmes4
(@holmes4)
Estimable Member
Re: Wits end

It's not extruding, just oozing/dribbling. There is some filament left in the hotend, and when it gets hot, it oozes out. I have seen this with every 3D printer I have had. Maybe try lowering your print temperature a bit if the temp you're using is on the high end for what the filament wants. There are a bunch of temperature tower test prints on Thingiverse that can help you determine a good temp for your particular filament.

I see the curling sometimes too. First thing is to clean off the outside of the nozzle when hot (using a towel). You may also want to try "cleaning filament" (I have some from eSun) - you load this as normal, and then unload. It has a rough texture and tends to pull out crud from the path.

Posted : 26/03/2019 5:49 pm
Bogwopit
(@bogwopit)
New Member
Topic starter answered:
Re: Wits end

I've seen the term oozing in a few places, but I wasn't sure that was the correct term, so thank you for confirming that 🙂

I'd agree with fiddling with the temps, but this has only started happening since the initial clog and it's the PLA that came with the printer, not a different manufacturer. As all the default settings from Prusa are based on 215 degrees, is lowering the temperature really the answer? Also, as my test have been confirming, the oozing starts from 195 degrees, which feels pretty low end for PLA.

Cleaning filament is on my list of things to acquire. How effective do you find it?

Posted : 26/03/2019 6:11 pm
bobstro
(@bobstro)
Illustrious Member
Re: Wits end

The filament not extruding evenly likely indicates a partial clog. When clear, the filament should flow out cleanly after a bit and coil up neatly. Read up on doing a cold pull. I've got some notes here.

That build-up of filament at the rear is going to bite you soon. Give the nozzle a bit of a clean. I like to heat it up and use some alcohol-dipped cardboard to pull away any accumulated gunk. If you're not using a coated nozzle, you can use a soft brass brush. Remove the part cooling duct and give the entire heater block a good clean, being very careful around the thermistor and heat cartridge wires.

The oozing is normal. The work-around is to use startup gcode that only heats the nozzle up to a "no ooze" temp before doing mesh bed leveling, the finishing up the warmup process to print temps after the bed temp is reached and leveling completed. Ideally, you want the nozzle warm (I used 160C) before doing mesh bed leveling to avoid driving a chunk of cold hard filament into the bed, but not so hot it oozes out like that. I've got some dated notes here on the process I use.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 26/03/2019 7:28 pm
holmes4
(@holmes4)
Estimable Member
Re: Wits end

I find 215 to be on the very high end for PLA, despite that being the MK3 default for preheat. I print at 200 with most of my filaments to good results. (Some "premium" filaments do better at 205.)

Follow bobstro's first link for info on doing the cold pull cleaning method. I see he too uses eSun cleaning filament. In addition to its cleaning features, it is also clear, and this helps you see contaminants.

Posted : 26/03/2019 9:31 pm
Pepe LePew
(@pepe-lepew)
Eminent Member
Re: Wits end

I do see that there is very little "if any" clearance between the nozzle and the heat block.
It looks to me that you have tightened the nozzle up against the heat block.
I personally would re-adjust the heat break and nozzle to give you a bit of clearance to
ensure that your nozzle is tight up against the heat break, not the heat block.
If there is a small gap between nozzle and heat break you could set yourself up for a clog.

Zoom in on the picture located here to get an idea of the gap needed between nozzle
and Heat Block. It will require that you adjust the heat break in order to achieve this.
Scroll to step 14

https://manual.prusa3d.com/Guide/5.+E-axis+assembly/1055

Posted : 29/03/2019 6:35 pm
randolph.l
(@randolph-l)
Honorable Member
Re: Wits end

or go straight to the company that makes the V6 for Prusa
https://e3d-online.dozuki.com/Guide/V6+Assembly/6?lang=en
and then read Step 3

Posted : 29/03/2019 11:07 pm
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