1. Got a question or need help troubleshooting? Post to the troubleshooting forum or Search the forums!

Unresolved Stud Thermistor Issues.

Discussion in 'Troubleshooting' started by Oisin, May 13, 2016.

  1. Oisin

    Oisin Member

    Joined:
    Apr 14, 2015
    Messages:
    384
    Likes Received:
    23
    Hi guys. I was wondering if anyone has the same thermistor as the one I posted an image of below. I've been through 6 of them in the last few months. After a few rounds of heating and cooling the adhesive separates and the thermistor comes out of the stud. This, of course, causes the prints to cancel if it happens in the middle of a job.

    It wasn't too much of an annoyance until the other night when it popped out of its stud DURING the heating process. At that stage, the printer will continue to try to heat up. Unfortunately the thermistor is measuring the air temperature, meaning the hot end just gets hotter and hotter. It began to smoke and thankfully I was in the room to kill the power.

    This being said, I have a few questions:

    1) Is there a safer stud thermistor I can use that anyone knows of?
    2) Is there a modification I can make to the firmware to make it safer (i.e. if the expected heating gradient isn't being followed, it cancels the heating process altogether.)
    3) Can someone with a better understanding of the materials around the hotend tell me what would have happened if I wasn't in the room to cut the power? Would it have been capable of starting a fire or would the heater cartridge wires have snapped?
     

    Attached Files:

    #1 Oisin, May 13, 2016
  2. Geof

    Geof Volunteer Moderator
    Staff Member

    Joined:
    Nov 9, 2015
    Messages:
    6,757
    Likes Received:
    2,339
    1. Www.printedsolid.com. M3 stud thermistor. Proven great quality.

    2.your firmware should have a max temp error and min temp error to cut out. If it's in between those numbers then not that in aware.

    3.it very likely could have been a...thermal event or melted. Always monitor your prints :). Lots of people set up webcams and the such. I install a fire extinguisher and a smoke detector for each printer. Makes me feel warm and cozy. There is a smoke detector that you wire into your printer that kills power when it senses smoke but I don't have any other information than they exist. I think @mark tomlinson , @WheresWaldo would know more than I do with much more valuable information.

    @Printed Solid is the owner of printedsolid.com who sells many 3d items including the m3 stud thermistor. (I assume yours is a m3 as well)
     
    #2 Geof, May 13, 2016
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    23,915
    Likes Received:
    7,338
    You, we posted a smoke detector with a shutoff for the printer to thingiverse.

    The only way that thermistor should be popping out of the epoxy is if it got too hot. SOme have a thermal limit of 260-ish and the newer ones over 300 (I think). @Printed Solid would know. I have one on the detail printer it works fine and has never even hiccuped. I use a thermocouple on the other one (with the volcano extruder) so that I can get really hot...
     
    #3 mark tomlinson, May 13, 2016
    Geof likes this.
  4. Oisin

    Oisin Member

    Joined:
    Apr 14, 2015
    Messages:
    384
    Likes Received:
    23
    Good call on the smoke detector. That's being integrated ASAP.

    The printer is definitely not getting as high as 260. It's getting to 195. Those 6 thermistors I've been through all failed in the exact same way, with the adhesive failing and letting the thermistor come out of the stud. Must just be cheap Chinese stuff or something!

    What I've done is physically secured the thermistor to the stud with wire. I then coated it in heat resistant silicone so hopefully it doesn't occur again.

    Thank you both for your replies. I'll search for the smoke detector on thingiverse.
     
    #4 Oisin, May 13, 2016

Share This Page