1 Topic by mdrVB6

  • mdrVB6
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Topic: I keep shorting my E3D thermistors

I've got an E3D V6 and I'm frustrated because I keep going thru a thermistor about every couple weeks or every spool or 2.  How long have you all been getting these things to last?  The issue is that the provided fiberglass sleeving melts or frays over time and leads to it shorting out and this forces a reset to the printer, ruining the print.

I've wrapped some kapton over the fiberglass sleeve and this lasted just a few more prints before it started shorting again.  I've got the fiberglass completely up against the head, although it has started to fray again.  Then I've got the kapton all the way against the head but it still shorted.  I actually have never broken a thermistor (knock on wood) but I'm on my third thermistor now because after it shorts a few times, the fiberglass is so frayed from inserting and removing it that it is useless to prevent further shorting.

Any tips to make these things stop shorting?  I've lost 4 good size prints already today.  I'm about to wrap some kapton around the entire heater block to reduce the metal area that it can contact to cause a short, but I think I shouldn't have to do that.  Thanks.

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed

2 Reply by elmoret

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Re: I keep shorting my E3D thermistors

If it frays, it is because it is being allowed to move.

If it is being allowed to move, it is not properly strain relieved/attached to the extruder body.

The portion of the thermistor cabling that is covered in blue fiberglass sleeving should not be moving or flexing during printing. If it is, you haven't properly secured your wiring.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

3 Reply by wardjr

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Re: I keep shorting my E3D thermistors

elmoret wrote:

If it frays, it is because it is being allowed to move.

If it is being allowed to move, it is not properly strain relieved/attached to the extruder body.

The portion of the thermistor cabling that is covered in blue fiberglass sleeving should not be moving or flexing during printing. If it is, you haven't properly secured your wiring.

Yep.

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4 Reply by mdrVB6 (edited by mdrVB6 2014-09-07 13:42:18)

  • mdrVB6
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Re: I keep shorting my E3D thermistors

elmoret wrote:

If it frays, it is because it is being allowed to move.

If it is being allowed to move, it is not properly strain relieved/attached to the extruder body.

The portion of the thermistor cabling that is covered in blue fiberglass sleeving should not be moving or flexing during printing. If it is, you haven't properly secured your wiring.


Any tips or pictures on how to actually secure it?  There's just not a lot of real estate in that area.  The best I can think of is making the next one a little longer and trying to tape it somewhere like the side of the hot end mount near the top.

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed

5 Reply by elmoret

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Re: I keep shorting my E3D thermistors

If the wiring is fully constrained relative to the extruder, and the hotend is fully constrained relative to the extruder, then the wiring between the extruder and hotend can't flex.

Tape is not a reliable solution. You have a 3D printer, modify an extruder body to have features for zip ties, print, install!

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

6 Reply by mdrVB6

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Re: I keep shorting my E3D thermistors

That still doesn't help with melting through the fiberglass, which is a contributing to all of my 3 failed thermistors and the only cause (no fraying) on one of them.  Look, I'm not trying to make a sympathy post, I know you have given a lot of people discounts for complaining and I'm not here to ask for that because I already placed an order for several more earlier today.  I can't be the only one who has had an issue with this and I really want to find a long term solution.

Has anyone successfully used something other than the supplied fiberglass tube to insulate the thermistor wires?  I will try to come up with another mount that includes a stud to zip tie the wires against, but it would be better to just use a more robust insulating material.

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed