How hot is too hot?  

Re: How hot is too hot?

I use no external heat source. I can only see a need if your room temperature is below Prusa MINTEMP. Otherwise printer operation provides all the heat that is needed.

Re: How hot is too hot?

Hmm, even without a heat source, my enclosure seems to be getting hot.

Did another ABS print, this time without the heater. I noticed after a longer period, the cooling shroud started drooping again. Not quite as bad, and it's a newer, slightly heavier one. It was 50c inside. It also appeared that the print itself was going slower. The steppers didn't feel overly hot though.

I had to open the "door" of my enclosure for the temp to drop down to a more reasonable 38c. I might have to put a fan on my enclosure rather than a heater!

I think what's happening is the screw for the shroud is losing it's grip when the plastic heats up, and it starts to loosen. There's no nut behind it, the screw just threads into the plastic housing. Once it cools, I can tighten the screw and the shroud pulls back up where it should be.

I'm thinking maybe a longer screw with a nut, but I'm not sure I can get the nut back there with the shroud I'm using.

I'm more concerned about what else might be affected though, and what the safe temp environment for the printer should be. My PS it outside, everything else is inside.

Re: How hot is too hot?

Is your enclosure a tight fit to the printer? I deliberately built mine high to have a larger volume of air in the enclosure to mitigate temperature problems. Each cabinet is 600 x 550 mm inside dimensions.

Re: How hot is too hot?

For abs printing remove the shroud. It has no use.
Something is wrong with your hot end. Maybe parts of the extruder are touching the heater block.

Re: How hot is too hot?

The shroud isn't my main concern, it's other parts. The shroud is more an indicator that bigger problems may arise.

Maybe parts of the extruder are touching the heater block.

I hadn't considered that. I don't think that's the case, but it's a possibility. I'm planning on partially disassembling the extruder body soon to better examine things and to see if I can get a nut behind the shroud bolt.

As I'm thinking about it, it stands to reason that it shouldn't be ambient temp in the enclosure since the heater block is considerably hotter and should be radiating higher temps to nearby parts than the ambient air temp. Yet as soon as I bring down the ambient temp, things improve.

Re: How hot is too hot?

It seems like the hot end is slightly rotated, causing the heat block either touch the housing, or get *really* close. It seems to have rotated while doing the cable management. It looks like a partial teardown is in my near future 🙁

Re: How hot is too hot?

no need to do any major disassembly to fix your issue .
just remove 2 bolts holding the cooling fan , then just loosen 2 bolts behind it .
now you can twist the hot end assembly .

before you do that , make sure your heat break is not loose from the heat sink and twists freely .this will cause other issues .

Re: How hot is too hot?

If only things were that easy. I believe part of why the block was rotated was when I routed the wires and bundled them up, the tension tugged on the head. There wasn't enough slack to safely rotate it back.

It wasn't too bad though, I just snipped off the tie wraps, unwound the sheathing a bit, and was able to pull the heater and thermistor cables from the controller just enough to get a tiny bit of slack, then tied it back up.

I ran out of time to re-check calibration though, so I need to do that, and then figure out why my first layer for ABS is so horrible. I'm sure pinda temp has something to do with it. I was using the experimental temp calibration set to on. Thinking that it might not be ready yet, I turned if off, and it seemed worse, causing the print to break loose and gunk up the heat block 🙁

Re: How hot is too hot?

I have my power suply outside the enclosure. The temperature, when I print with ABS, is arount 35. The PSU gets above 50.

Re: How hot is too hot?

I have a fan and heater in my enclosure. When printing with ABS, I've been keeping the enclosure interior at 60 C. Power comes from outside.

Re: How hot is too hot?

I've been keeping the enclosure interior at 60
That's a good data point, thanks.
No issues with the fan shroud drooping or the hot end cover melting at those temps?

Re: How hot is too hot?

Nope, everything is fine. My fan shroud is ABS, but other extruder parts are stock (PETG).

I am going to replace the part that hits the x-axis end stop, however, as I had a bit of a tumorous growth of PLA that deformed it and made a giant mess. I had to tape a piece of steel to the button-poker to get it to push before running out of travel. 🙁 That accident had nothing to do with the enclosure temperature and everything to do with a nozzle clog-then-unclog that cause all further material to stick to the nozzle. I didn't notice for several hours.