Cannot get to the PTFE Tube  

RE: Cannot get to the PTFE Tube

Spent some time on the live chat.  Was basically told to keep doing what I'm doing, and I can order more parts if something breaks.  It is a really tough pill to swallow to have a suggested course of action to fix a known problem, but when that doesn't work the response is just "keep doing it and if it breaks buy a new part."  I have been trying to get the fitting unscrewed, but now the bolt is nearly stripped.  The suggestion that I get a tool that fits is not really applicable in the realm of stripped hardware.  The brass is simply too soft, and wont budge.  My only option now is to spend 25% of the purchase price of a new printer to buy a replacement part, wait a few weeks for it to arrive, and I guess pray that this problem doesn't repeat or that the new item can be disassembled.  From the forums it sounds like this is a one off problem, fingers crossed.  Been a 3d pinterer for 48 hours and i guess I'm getting a solid dose of what it's like to be a 3d printerer.

RE: Cannot get to the PTFE Tube

I am a long time 3D printer and have the MK3 as well.  Just put the Mini together and was running the z test pattern a few times for adjustment.  Started off fine with full extrusion but now extrusion thins out and stops.

No clogs, I can unload and reload filament.  I've run the same filament load a number of times and it flows nicely.  Without unloading I do more loads and show the filament keeps flowing nicely, but as soon as I try another test print I lose extrusion.

Based on what I'm reading above, I assume I'm having the same problem with heat creep.  Will follow the guide, but for a brand new machine this is wrong.  I'll contact support as well and update this thread.

RE: Cannot get to the PTFE Tube

Update on my situation.

Turned out that my PTFE tube was short also and the spare was the right length.  All sorts of problems to get it all corrected though. But I think that getting all the cold pulls to clean out the tiny bit at the bottom due to the initial factory installation error (tube itself was clean)  and then following the guides did the trick.  A lot of work for a new printer, especially for someone who gets this as a first printer.  The kicker was that filament loading/unloading was clean and sometimes the z calibration pattern printed but thinner than it should have been.  New person would not know the difference.

what the guides do not mention is that after changing to the correct tube length and getting it properly put together, that PINDA was now lower than the nozzle itself.  No guides on getting that fixed, fortunately I recall adjusting the PINDA on the MK3 upgrade.

RE: Cannot get to the PTFE Tube

@reddadsteve

I can relate 100% to what you are saying. The Mini is my first printer and I had the problem with heat creap and the PTFE tube beeing too short. I had no idea what the first layer should look like or what a cold pull was and how a successful cold pull looked like. I spent 3-4 days working it out and learning what the problem was. Since this is/was a common problem there fortunately is a lot of help and guides to find. 

RE: Cannot get to the PTFE Tube

@reddadsteve

For future reference (and others who may read this thread): Adjusting the MINDA Probe https://help.prusa3d.com/en/guide/troubleshooting-the-mini_7848#7904

RE: Cannot get to the PTFE Tube

@gordon-w   Thank you.  Actually I ran into that guide later on.   I also added a comment on the guide for the PTFE tube replacement mentioning that the MINDA should be checked after replacing the tube (I still thought it was  called a PINDA!).  Normally simply replacing the tube would not affect the MINDA, but if the original one is short then the MINDA could be severely affected. 

Of note, looking at the 'short' tube that I pulled out, I now see that not only is it shorter but the ends are not as tapered as the long tube.  Leads me to think that the tube is not simply shorter but was actually meant for another purpose and was used by accident during build time.