Multiple print failures  

RE: Multiple print failures

I am also suffering from underextrusion and also had to replace completely jammed PTFE tube. My thread is here.

Last time on support chat they suggested I mesaured the extruder thermistor resistace which was 70kOhm. Tehy said this was not right (forgot to ask what would be the correct resistance sadly...). At the moment I am waiting for the spare thermistor. Hope this will help as I already replaced the nozzle, put new thermal paste between the heatsink and heatbreak, tried many different filaments, calibrated whatever I could, etc...

Maybe worth trying to replace the thermistor? It's cheap (approx. $9 or so) and easy to swap.

RE: Multiple print failures

Prusa are going to send me a replacement printer.  They are as baffled as I am by my 30 second extrusion variation cycles.  A  friend thinks I might be detecting gravitational waves.  So here comes my Nobel prize........

RE: Multiple print failures

Ha, Nobel Prize for Gravitation wave detection has already been won - sorry 🙂    -  look/google for "LIGO".
Just wanted to let you know that my new thermistor has arrived (at last!) and so far my problem seems to be gone!!! Too early be 100% sure but all critical prints where I always suffered underextrusion went through well.

Getting on with some Face Mask prints (more here).

RE: Multiple print failures

You've spoiled my day now dashing my hopes.... 😭 

Happy to hear that your problems has been solved.  Good luck with it.

RE: Multiple print failures

@makak007

At 20°C 986kOhm at 30°C 966kOhm

RE: Multiple print failures

@makak007

At 20°C 126,8 Ohm at 30°C 79,36 kOhm

RE: Multiple print failures

That's quite interesting as my new thermistor showed approx. 130kOhm @22-24C and the old (faulty) one showed between 70-110kOhm @ 22-24C (was varying a LOT without any temperature change so I assume this was part of it's malfunctioning). With rising temperature the resistance falls steeply down, @ cca 200C it was only a few Ohms. But yours shows values one order of magnitude higher.
Unfortunately I haven't found any technical specs for the thermistor.

RE: Multiple print failures

Sorry I had to correct the figures see upper

RE: Multiple print failures

Oh yes, now these are totally corresponding figures! Glad I have proper values 🙂

RE: Multiple print failures

I thought I should give an update to my friends here who were helping me.

I got a replacement printer from Prusa, and after a few initial hiccups, it is working fine. (They didn;t tell if they found what as wrong with the old one!) 

I got involved in printing supports for face shields here. I did about 40 successfully, but had problems with PETG.  One major issue what they were requiring these to be compliant with medical standards which meant that minor flaws - i.e.very small short gaps between layers - made them unacceptable.  I was getting a lot of waste parts, so gave up.  They have now stopped doing them altogether.

I have a different problem now which is really to do with my ignorance, but I am going to start  new thread for that.

Thank you again for your help.

RE: Multiple print failures

Posted by: @epzcaw

I thought I should give an update to my friends here who were helping me.

I got a replacement printer from Prusa, and after a few initial hiccups, it is working fine. (They didn;t tell if they found what as wrong with the old one!) 

Glad to hear it! You went through a lot. Good on ya for sticking with it.

I got involved in printing supports for face shields here. I did about 40 successfully, but had problems with PETG.  One major issue what they were requiring these to be compliant with medical standards which meant that minor flaws - i.e.very small short gaps between layers - made them unacceptable.  I was getting a lot of waste parts, so gave up.  They have now stopped doing them altogether.

Our local needs weren't as picky -- or perhaps circumstances were more dire -- and I got involved myself. Every area seems to have been unique. Locally, they were accepting a variety of qualities and materials -- PLA for single use, PETG for reusable -- but only wanted shields of a particular design that was slow to print. Fortunately, demand has died down here in Massachusetts and the supply chain seems more robust, so I'm back to hobby printing.

Glad you're back with us. I expect your grandson is going to have some good times learning with you.