A small gap inside the groovemount causes clog?

[mogcaiz]

Hi, I've had my M2 for about a year now. I just stumbled on a problem I cannot seem to fix or find a way around. Been trying over and over again, but the same happens, and I'm stuck and can't print. It's a sad day.

I had a small clog and did my routine of cleaning the nozzle and peek barrel with a butane torch to get rid of all the leftover PLA. works 100% of the time in my experience so no problem there.

After reassembling the cleaned parts, and starting up the printer again, I could easily let the filament flow through again, however once I started a print, it clogged immediately.
I noticed when I disassembled the parts, there was a thick layer of PLA stuck on top of the peek barrel which covered the entry hole itself. All this happening inside the groove mount. It seems to me there is a small 1mm gap inside the grovemount where filament can go astray and cause an immediate clog.


As you can see in the picture, there is a small layer of melted plastic on the left, covering the entry hole.

Once I removed the clog, the plastic could flow freely again, and clog once I started a print. Or it would clog immediately. I noticed if it didn't clog immediately, it would definitely clog when doing a retract followed by an extrude.

Here is what I think has happened, based on the location of the clog:

I've no idea why this has become a problem now, since I assume the small gap has always been there.
Everytime I clean the nozzle and the barrel, it clogs again now.

I measured the PLA to be 1.73mm, and less than 2 weeks old, so I doubt it has to do with the filament.
I've cleaned with a butane torch and tried 6-7 times since this issue first started, all yielded the same results.
The groove mount, peek barrel and nozzle is less than 3 months old, which replaced the first old ones.
However I tested with the first old groove mount I received, and now exactly same thing happens there with those. I didn't have this problem before.

I made sure I tighten all the parts together when I reassemble, I don't know if that 1mm air gap inside the groove mount has always been there or not, but if it has, why suddenly a problem now?

I've tried printing at 185, 195, and 200 celcius, and it made no difference.

So any ideas?

[Toby]

I assume these aren't v3b hot ends? If they are, then the printing temps should be 20 degrees higher.

Not sure if this might cause the symptoms you see, but maybe the temperature readings aren't accurate anymore, and this is causing the filament to back up rather than extrude?

[jimc]

its been a good month or two since i have had my v3b apart so someone can correct me if i am wrong but there should not be a gap. the brass barrel should be tightened all the way until it hits the ptfe/white plastic sleeve inside the peek. if you have a gap then you didnt thread it into the peek far enough.

[mogcaiz]

Toby: Yes, I use v3b hotend. I also updated the M2 firmware on my Rambo board so it *should* read and assign the temperature correctly. However it might be a solution to print at a higher temp, so the upper parts of the barrel is hot enough to keep the plastic liquid.

jimc: I wouldn't know if there is supposed to be a gap or not, but it does make sense. Maybe someone from M2 team could confirm this. All I know I tried to tighten it as much as I could with a pair of pliers. But perhaps I could tighten it even more. Any tips on how to use pliers without damaging the peek brazzel from the grip?

[Toby]

Yes, I would try printing at higher temps. Makergear says the v3b hot ends need to be set at 20 degrees higher than the previous hot ends. Something about the temperature sensor being in a different location iirc. I print Makergear PLA at 215 successfully, and i know others go all the way up to 225.

Why this should only recently start affected your prints is a mystery, but still worth a try I think.

[ajw05001]

You may consider trying to tighten the extruder nozzle while it is at higher temp with some pliers/wrench. If you tightened at RT, you may still have a gap, whereas heating up will give the threads room to continue screwing in. I've noticed that on Makerbot at least. Let me know if it works.

[helix_3]

its been a good month or two since i have had my v3b apart so someone can correct me if i am wrong but there should not be a gap. the brass barrel should be tightened all the way until it hits the ptfe/white plastic sleeve inside the peek. if you have a gap then you didnt thread it into the peek far enough.

Don't forget to include the 2.5-3.0 mm gap: http://makergear.wikidot.com/m2-hotend-assembly