Prints stopping after about two hours even with complete new hotend  

RE: Prints stopping after about two hours even with complete new hotend

Hi,

To help, I think the community will need a bit more info to work with.

A good start will be if you can explain exactly how a print stops. Does all X-Y-Z-E movement suddenly cease or only the extrusion stops? Any error messages? Is the printer still responsive to front panel commands? Are there any common circumstances between different prints stopping? e.g. stopping around the same print height above the bed.

Cheers,

Tim

RE: Prints stopping after about two hours even with complete new hotend

Hi Yes, sorry, I will explain,

It seems to be about the same height, although I have run all axis and there is no resistance.

I haven't actually seen the print stop, when I return, there are no errors, and the extruder is back left as if it has finished.

The print itself, so far, looks fine after the stoppage.

Front panel is responsive.

I have another print going now which I will stay near so I can see if I see or hear anything, all looks good so far, but it is on layer 2....

RE: Prints stopping after about two hours even with complete new hotend

When you have found it in that 'finished' state, is the Z-axis on the same level as the last successfully printed layer or is it at the height you would expect for a fully successful print?

Keep us posted on your observations!

Cheers,

Tim

RE: Prints stopping after about two hours even with complete new hotend

Are you printing from the SD card or Octoprint or…? 

RE: Prints stopping after about two hours even with complete new hotend

SD card, I have about 12 different ones I use between printers to keep the number of files down on each of them for faster loading and printer menu performance.....

That's actually one thing I haven't checked, the SD card, but I have been using the same ones for a few years now, I will try another on it now

RE: Prints stopping after about two hours even with complete new hotend

The Z axis has raised as if it has finished and the total elapsed time is showing as if the full print has complete....

Maybe an SD card issue as the guy above has said, I will try a different one now, but I have never seen an SD card issue, but I suppose it could happen.

Thanks for the reply, I will let you know.

RE:

Try the suspect SD card on another machine too.

As the print seems to be finishing in terms of X-Y-Z movement, then that would imply the G-code is being properly read out from the card. If the SD card was actually bad, you would expect the file to be corrupted and for the print not to work at all.

Another possibility could be a broken wire in the umbilical going to the extruder. The broken wire could be making a connection at low heights but after a certain z-height the connection is broken and no more plastic is extruded. That said, I would probably not expect to see a hard transition from one state to the other in such a scenario - so typically the top of the print would look messy which, from what you have said, it does not.

Perhaps also try printing a simple tall object - say a 1 cm x 1 cm x 10 cm solid. It will go quite fast (1h20m with 0.2mm SPEED profile) and you can perhaps monitor that a bit more easily or shoot a video. Being less than 2 hours, the success (or not) of that print would also test whether elapsed print time is a factor.

Cheers,

Tim

RE: Prints stopping after about two hours even with complete new hotend

So a little update, and still not fixed...

I put the SD card in another printer, and it printed fine so I don't think the card was the issue, it also looks fine in Windows. The next print with another SD card was fine so I thought the issue might be fixed and that the printer was just having a hissy fit with that particular SD card. 

The next print it didn't put about 10 lines down on the initial layer and then put the rest down so I had to stop that.

I have tried with the tension screw tighter, looser, a lot tighter, and a lot looser, some prints are OK others fail. I have tried tall prints, some work and some fail so I don't think it is a height thing.

The two prints I watched start to fail yesterday, the printer is moving but no filament is coming out for about 10 mins. The extruder motor isn't moving, I have a line drawn on it. I don't know if it isn't moving because it is broken, or there is a jam somewhere? This is a brand new hotend. I stopped the print at this point.

I left another running for about 6 hours yesterday into a 9 hour print and all was good, went to bed, just woke up, and it has failed. The extruder has moved to the back left and risen, so it looks like it thinks it has finished. When I try to 'unload filament' now the extruder motor doesn't move and the filament won't come out. I have to unscrew fully the tension screw and pull the filament out.

To me, now, it looks like an extruder motor problem, is this a 'thing'? Do they fail? I have A/c on in the room set to 22 degrees, so I don't think it is too hot, it, along with the other printers, and fully open and in no enclosure?

Is there a test I can run on the extruder motor?

Thanks

RE: Prints stopping after about two hours even with complete new hotend

Just another update, I have just tried to load filament again, the extruder motor is not moving, just running a self-test now, to see what it says....

RE: Prints stopping after about two hours even with complete new hotend

Good updates!

Based on the evidence, I see three possibilities:

1. There is an intermittent connection to the extruder at the plug in the EINSY box. Try unplugging and re-plugging a few times to wipe the contacts (machine powered down of course).
2. There is a broken wire in the cable bundle going to the extruder which is intermittently connecting/disconnecting. I think the cable can be unplugged from the extruder end, although I have never done this. If you can unplug it, then try another cable between the EINSY box and the extruder if you have one.
3. The motor itself has some intermittent connection internally - try another motor if you have one.

Your last post suggests that the fault may now have become 'hard'.

Hope that helps.

Cheers,

Tim

RE: Prints stopping after about two hours even with complete new hotend

Thanks Tim, I am out and about today but I will try tomorrow. Prusa doesn't have any spare motors on the site at the moment, they are out of stock.

RE: Prints stopping after about two hours even with complete new hotend

Sounds like an issue with the filament sensor.

Just my 2c

Chris