Extruder overheating --- causes?

[Dave Durant]

Fan --- to cool extruder

I wouldn't bother, unless it's trivially easy or you have another reason to add a fan.

You've got some (quite serious?) problem with the machine that is not due to it not having a fan.. Adding a fan might lessen the symptom but the problem will still be there.

I like cvoinescu's idea of the PID being really screwy. If nothing else, it's probably easier to test & fix firmware issues than electrical ones.

[WillAdams]

Okay, it's my understanding that the all-metal hot ends want active cooling when printing PLA, so the fan still feels right to me (it helps that I can pick it up cash-and-carry at Radio Shack on my way home).

Looking back, it seems as if this might be the chain of events:

- ran the hot end into one of the binder clips on the print bed
- perhaps this cracked something inside, creating a thermal break
- the hot end would then heat up inconsistently depending on whether or no the broken pieces were in contact w/ each other

Regardless, I have to replace the mangled hot end before I can begin testing.

Agree that once I install it I'll need to:

- verify the firmware (it's a Smoothieboard (Azteeg x5 mini) and loads that from a file --- will make sure the file isn't corrupt)
- carefully install things
- carefully test all the connections
- run temperature calibration

anything I'm missing? Hopefully third time will be the charm.

[cvoinescu]

True, you almost certainly need a fan for an all-metal hot end with PLA, and, depending on design, ABS too. My J-Head (which is not all-metal, obviously) prints PLA without a fan with zero problems, but YMMV, and a fan is recommended. Still, the temperature excursion is a problem you need to fix.

[Dave Durant]

Looking back, it seems as if this might be the chain of events:

It would be nicer if it was a firmware problem but this sounds like an electrical problem. Also, I would look for shorts instead of things related to thermal conductivity.

Like, if you were to picture a graph of the temperature, a flaky connection would give you a lumpy or spiky graph. Having a crack in something that's supposed to conduct heat (or some other physical heat-conducting problem) wouldn't have lumpy or spiky graph, it would just be more shallow than it should be. From what you've said, it sounds like you have a lumpy graph.

[Dave Durant]

prints PLA without a fan with zero problems.

I've never heard of this (which does not at all mean it does not exist).

What sort of feed rate do you normally print at?

[WillAdams]

It would be nicer if it was a firmware problem but this sounds like an electrical problem.

Okay. Suggestions on how to test this? I've got a multimeter which I barely know how to turn on.

[Dave Durant]

Suggestions on how to test this?

Sorry.. My limit on electronics maxes out at "look at all the wires and see if they're connected."

[Dave Durant]

Any progress on chasing down this problem, Will?

[WillAdams]

I've ordered a Pico Hot End from B3 Innovations. (and it turns out I didn't need to buy the fan --- one is included w/ the hot end --- oh well, the one I've been using to cool the electronics is large and clunky and a bit loud, so I'll swap things around)

Once it arrives I'll re-wire my electronics and test it w/ the brand new hot end, thermistor, heating cartridge and fan wired in for active cooling and we'll see how things work.

William

[WillAdams]

I am however, kind of regretting not getting a: http://e3d-online.com/E3D-v6/Full-Kit/v ... -Universal

and may have to buy a second hot end (hey, I need to convert my SO1 back into a Repstrapoko!) so as to be able to do a head-to-head comparison.

William