So my first silicone heater failed after being moved back and forth from printer to printer - at one point, it simply stopped effectively heating, and from testing around it felt like a broken wire. So i cut it open to get a better look inside!
The thermistor is crimped and insulated in PTFE tube, i suppose that was round at some point. And as expected, it’s simply sitting on top of the heater part. Now, the heater wiring is where it gets interesting: There are sheet metal brackets embedded in the silicone, supposedly for strain relief, which have the supply wire soldered on on one side and the heater wire simply wrapped around the other. I guess this is where this bed failed, since its much too easy for the coiled heater wire to lose its tension over time and then score and burn the few contact points that are left. I think this should really be crimped in some way and not just wrapped, but there might be some technical factor inhibiting that.
For good measure, i then sliced apart the rest of the bed to see more of the heater wire, and it all seems to be solidly embedded in the glass-fiber reinforced silicone.
This one failed after about two year of intensive use, what are your experiences with these heaters?
Well I was thinking about a silicone heater cause I had one on the old printer. Was good and reliable at the old one. Now ive got an mk3 alubed which seems to warp. Any suggestions there?
@Mark_Rehorst i moved it with the aluminum plate attached, i guess the movement from tucking the cord in and relocating it ultimately led to its demise. And the “3M” adhesive underneath still held up fine, but was completely dried up, as expected.
Other than thermistor failures, I have had nothing but great performance on all of mine. In the future if I buy any more mine will just have a hole in the center of the pad to locate the thermistor in the bed plate instead of encapsulated in the pad.
Do you remember who you bought it from? Maybe it’s worth buying some smaller cheaper ones from Keenovo and AliRubber/AliBrother and dissecting them to make sure they’re built well now. I had AliRubber make me a couple custom ones and now I’m concerned. I remove my bed for transport.
Yeah, Nichrome resistance wire is a bitch to actually connect to - usually they’ll just wrap it or crimp it. You see this a lot on heater cartridges, the nichrome comes out of the cart, and they crimp a connector on and then normal wire afterwards. Nichrome has to be welded, it can’t really be soldered, and even then it’s difficult to do right.
Best when welded, I know a lot of people use capacitor banks to weld them to wires.
Is the nicrome wrapped around a fiberglass core? I’m curious how hard it would be to make yourself. I have wanted to make/buy a kapton heater that would fit, you could save 100-200 grams in bed weight.
I like the idea of running nichrome wire on a Kapton backer. Use a pre-cut one if there is one that fits your need. Routing your own would take some planning to be sure it’s within a target power range. The nice thing about the silicone ones is they can make a custom size, shape and power.
This is stuff I want to know about