Plastruder MK5 Heating Element Won't Heat Up

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Will Smith

Sep 23, 2010, 5:16:36 PM9/23/10
to MakerBot Operators
Hey all,

More MK5 problems for me. I was just getting everything dialed in
nicely, too.

When I set the Plastruder temp to 210C to warm it up, it seems like
it's only getting to 160C. I verified that temperature, so it's not a
thermistor problem. I did notice something weird on one of the heating
elements when I was checking to make sure that my connections were
still good. It seems that the resistor slides in and out of one of the
heatsinks very easily. Since that doesn't happen on the other side, I
assume one of them isn't right. Would this prevent the bot from
heating up?



Stan Seibert

Sep 23, 2010, 5:38:01 PM9/23/10
to MakerBot Operators
A loose heatsink might indicate poor heat transfer from the resistor
to the steel block.

Quick sanity check first: Did you update your PID settings when you
installed the MK5?

Will Smith

Sep 23, 2010, 5:59:30 PM9/23/10
to MakerBot Operators
Yes. I've changed the PID settings, and am running ReplicatorG 019.

Just to be clear, the heatsink is bolted tight to the steel block that
the nozzle is screwed into. The thing that's loose is the round thing
(I assume it's a resistor) inside the heating element itself.


Sep 23, 2010, 6:16:39 PM9/23/10
to MakerBot Operators

A loose resistor inside the heatsink will give you less of a heat
transfer than a tight one, but you should still be ok. I would
recommend you turn off everything and let the temp settle to match the
room, then heat it up again and verify that the loose power resistor
is in fact heating up and not broken.

My first thought is that you may have hooked up the heaters in series
instead of parallel, making them far less powerful. Can you verify
that you are definitely hooked up in parallel?


Achilles Boiser

Sep 23, 2010, 6:31:16 PM9/23/10
There's small threaded holes in the block for both resistors to bolt onto.  So how can they slide?

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Will Smith

Sep 23, 2010, 6:44:06 PM9/23/10
to MakerBot Operators
It's cooling off right now. I'll fire it back up again in a bit and
check it out.

I'm pretty sure the resistors are wired in parallel. It was heating up
fine until this morning. (For what it's worth, one wire goes from the
relay board to one terminal of the first heating element then to a
terminal of the second heating element. The other wire runs from the
second heating element back to the first heating element, and then
back to the relay board).

Looking at the connections again, I'm wondering if the high-temp
solder I used wasn't high-temp enough. It's looking a little
tarnished. When the thermistor was loose, I probably hit 250C before I
fixed it, which could have broken my connections. I'm going to see if
I can find some high-temp solder in San Francisco someplace tonight,
resolder it tomorrow, and try it out again.

Anderson Ta

Sep 23, 2010, 6:48:33 PM9/23/10
Did you check your solder connections?

Luis E. Rodriguez

Sep 23, 2010, 7:01:14 PM9/23/10
Charles Pax snipped the ring at the ends of the resistor and crimped
the Teflon coated wire. I threaded the wire in a way that ensured
physical contact. I bought silver solder but not high temp enough. I
solder-sucked off the extra because it liquified at operating temp.

Luis E. Rodriguez

*sent from iPhone 4

Achilles Boiser

Sep 23, 2010, 8:46:50 PM9/23/10
I used solder that I purchased from home depot.  It's not one used for electronics but it works and doesn't melt away. 

Theron Trowbridge

Sep 23, 2010, 9:22:45 PM9/23/10
I was having a similar problem until I upgraded the extruder controller to the latest firmware.  I suspect I could have overcome the issue with PID settings, but the firmware definitely fixed something.


Martin Bogomolni

Sep 23, 2010, 9:45:29 PM9/23/10
I've stopped using solder altogether. I'm using pure crimped
connectors and steel screw terminals now. That's pretty much the way
things have to be with very hot connections...


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