Fix prusa MK2 after accident
Hi there
We have had one month happy with PRUSA MK2. The printing quality was really good. However, happy time was up two days ago.
We have to fix the PRUSA MK2 now since the accident happened.
you see the attached photo for detail
The problem is that the part failed to stick on the heated bed in the middle of the night. the printer was not aware of this (I wish it could) and continue to pump material out. OF course this does not result in a nice part but a blob of material. It even big enough to press the heated bed down for several millimeters. The material fully melted out and block the whole bottom face of the printing head. No way to remove the material cleanly and safely. We have used heat gun to melt but it took so much time and not efficient.
We are not sure if we can fully recover it without new replacement part. But in the mean time I want to reach you guys for few questions
1) CAN prusa can improve the software that is able to be aware of collision and stop the machine safely before this kind of issue happens. Principally, the nozzle never get external collision in a long time, let say few minutes. Only time that could happen is when it slightly hit the printed part. So why not having some kind of current/force detection here.
2) In case we have to fix, we wonder if Prusa sells individual parts, hotend, sensor? Otherwise, is this hotend compatible with MK2
http://e3d-online.com/E3D-v6/v6-1.75mm-Universal
3) where to by the inductive sensor that compatible with MK2
Cheers
Re: Fix prusa MK2 after accident
try to tidy up as much as you can do. maybe you'll need to use a hot air gun.
you can find a few threads here at the forum with pictures like yours... and reports of failed prints.
for the replacement for the inductive sensor: go to the prusa shop, use the customer chat and ask them to enable your account to access the spare parts section (where you can get heatbed, p.i.n.d.a. probe, fan etc.).
but beware: shipping is quite expensive.
dem inscheniör is' nix zu schwör...
Re: Fix prusa MK2 after accident
That looks really bad. Ask Prusa chat to open the spare part list for you. Guess you also need a new PINDA. Check the forum for other BLOBS there were few i saw maybe you can find help there.
Re: Fix prusa MK2 after accident
Yes, it did look really bad when we had to spend hours hto melt the PLA blob and still was not able to remove it. Compared to our old LUZbot, I had had very good impression about this machine before this happening. What annoying me now is not how to fix it, but mainly how to avoid this kind of situation not happening again. I do not want to change hotend every few months or even weeks. And I am quite suprise there are not many peope having the same problem as mine. The chance that can happen quite high.
If you print something large in volume but low in height and the part does not stick to the heated bed, the printing head will move the mess of material with it and continuously pump out material over 10 hours and you get a blob of plastic stuck between nozzle and bed
Re: Fix prusa MK2 after accident
2 things:
1) Use the LCD menu to pause the print for up to 24hrs and only print during the daytime ( read the forum on how to turn off the heat to the nozzle and bed when pausing for more than just a few minutes).
2) Use a trip wire to stop the print, see http://shop.prusa3d.com/forum/improvements-f14/print-failure-detection-t2585.html
2a) I think disconnecting the wire going to the thermister will cause a min temp error and stop the print, so the trip wire could break the connection to the thermister which would stop the print, correct?
Re: Fix prusa MK2 after accident
...If you print something large in volume but low in height and the part does not stick to the heated bed...
so it all comes down to find the proper 1st layer adjustment to get the best adhesion to the printbed.
dem inscheniör is' nix zu schwör...
Re: Fix prusa MK2 after accident
Prusa should be including the silicone covers that e3d offers - they are very inexpensive, and have saved me a few times from similar situations.
Were you playing with different nozzles prior to this problem? I see plastic that has extruded out the top of the hotend, and the kind of melting on your filament looks like it wasn't pushing out the nozzle but rather out the top and down onto the hotend and down (a big no no).
The nozzle and the thermal tube need to be tight together when you assemble the hotend. If there is any gap, you get this sort of issue. It should be tightened when the whole hotend is 260+ degrees.
You might still be able to salvage it - just requires you remove the hotend/coldend - put it on a frying pan with a oven glove underneath for insulation. Attach the blue shroud and coldend fan (to keep the coldend from heating up) - then heat up to 240 degrees. You can handle the coldend mostly but don't touch the hotend. Slowly remove all the goopy mess with some pliers. Then unscrew the coldend. When you remove the coldend, wipe it off quickly with a rag to clear out the threads (while it is still warm). Screw it in and remove a few times and remove any remaining plastic you can get (doesn't need to be perfect. Check that the cold end hole doesn't have any plastic inside and then follow the e3d guide for v6 assembly making sure the thermal tube (attached to the cold end) and the nozzle are tight against eachother.
Cool down, and check that the cold end doesn't have any play or that you can twist it off. This might not be the correct way, but its what worked for me. No guarantees of course.
Re: Fix prusa MK2 after accident
I agree entirely that this is a problem that needs to be solved. For some reason, the 3D printing industry has stuck to this idea that a 3D printer is a toy instead of a real product that performs a task. Imagine selling a laser printer, that when it jammed it would just keep printing and destroy itself. The first time that happened the printer company would be called out and would never be in business again. But it gets even worse. Did you ever see a laser printer that would continue to print in the air when the paper ran out? Of course not as even the cheapest $50 laser printer stops when paper is empty, you fill the paper and continue. But on a 3D printer, forget having a filament sensor. Rather if filament runs out, you just throw away you 20 hours of print work and start again. Again, if the most basic of laser printer didn't have this protection, they would be the laughing stock of the industry, but for 3D printing, its expected.
I say forget muticolor printing for now and get the basics worked out first.
1) Loose print detection (Print Jam Detection) A camera could fairly easily provide this.
2) Filament sensor
3) Network connectivity STANDARD. Printer power turns on and off automatically.
4) Auto bed leveling STANDARD.
5) Automatic nozzle height setting based on the material printed, and maybe automatic fine tuning.
6) Completely automatic filament loading and unloading.
Leave the toys for the kids, and make a 3D printer, a real product.
Re: Fix prusa MK2 after accident
The problem with all this electronic wizardry is, it's a hobby printer. Sure people use them to run farms and sell parts, etc., but they also realize they are going to have to have some kind of know how to rebuild to get it back going again. Once you start adding detection the cost rises, and puts it out of reach of hobbyists. Follow the advice of people trying to help you, and you will be successful in repairing it. Good luck, I had this happen on a printrbot, and it took several hours and lots of different tools to get the blob off the hotend, out of the heat sleeve, and get it going again.