Any reason for the 262 C max temp?

Sethipus

I was trying to print some PCMax and ePC at 270 C, but my hotend wouldn't go above 260, and I discovered reading the Wiki that after some version of Reprap firmware the default maximum is 262 C.

I just added two M143 commands to config.g to set the max temperature of both hotends to 275 C.

Is there any reason the max temperature was set to 262 C? That seems like an awfully specific number, so it gives me pause to just change it uninformed.

dc42

After some discussion with others I chose 260C as a likely maximum temperature that a user would need to set when printing common filaments, then I added 2C to allow for overshoot when heating up.

zzing

This caused me to waste about half an hour being utterly frustrated because I couldn't get it up to 285 to change my nozzle - and nothing told me anything.

iDevelo

Here's what i use for reference:

M143 H0 S110                                      ; Set maximum temperature for bed to 110C
M143 H1 S285                                      ; Set maximum temperature for hotend to 285C

Sethipus

Thanks David for the response.

dc42

btw the reason for having a default limit was that most hot ends don't like high temperatures, because they have either a thermistor with a temperature limit of (typically) around 270-280C or a PTFE liner.

GrodanB

So the fact that E3D recommend 285 for nozzle change is not useful…

hmm...

my bad...

P1 is not correct... H1...

Jackal

@GrodanB:

So the fact that E3D recommend 285 for nozzle change is not useful…

I can't override?

Or 262 is good enough for nozzle change?

Read the reply a few post above

dc42

@GrodanB:

So the fact that E3D recommend 285 for nozzle change is not useful…

Can you give me a link to that? I'm quite happy to increase the default maximum temperature if that would help users.

GrodanB

Yes: https://wiki.e3d-online.com/wiki/E3D-v6_Documentation#Swapping

dc42

Thanks, I'll increase the default limit to 288C in the next release.