2.4 beta 2 nozzle temperature bug

[rexipus 0]

I recently switched from 2.4 beta to 2.4 beta 2, and I've started seeing a new problem that I've never before seen in the 6 or 7 months I've been using Cura.

The nozzle temperature is showing up in the gcode file 5 C higher than it was set in Cura 2.4 beta 2.

I routinely set my PETG nozzle temp to 245 C, and was surprised to see my temp was at 250 C. I manually set it to 245 and continued that print. Then my next print was at 250 C, and my next. I have looked around inside of Cura to make sure that I was doing it correctly, and I was. The bottom line is I am having either to manually set my nozzle temp to 240 C in Cura so that it appears in the gcode as 245 C, or else I leave it at 245 C and then manually edit the M104 and M109 commands from 250 back down to 245.

Anyone else seeing this? This has been quite a bother for me, because I keep forgetting to manually correct the temps to 245 C, so my Duet Wifi controller will heat up the nozzle to 250 before it drops back to 245 when I manually set the temp to 245 in the Duet Wifi control page. The problem with this is that I'm still using my stock hot end with a PTFE nozzle, and 250 C is really too high, and threatens to damage my PTFE liner. It's tolerating 245 C, but just barely: I cooked a PTFE liner experimenting with 255 C before, so this is right on, or just over the line.

[ahoeben 1,852]

There's a new setting in Cura 2.4 to allow you to set the nozzle temperature for the first layer. By default this is set to the normal nozzle temperature + 5.

On a personal note: this is exactly why I argued that this should not be the default, even if the +5 degrees for the first layer may give better result for some (most?) materials. I feel your confusion.

[rexipus 0]

Oh wow, I had no idea.

Yeah, adding 5 C by default to the starting temperature is just ludicrous. Why 5 C? What about different materials? What about different build surfaces? What about the fact that people have already tweaked their settings and arrived at settings and profiles and whatnot that work for them? And then the new Cura version steps in and makes a decision for them and changes things up.

Wow. If this is in any way a democracy, then I vote NO. Don't ever, EVER change my settings by default with a new version of the program. Just don't do it. If you want to give me new options that's great. But don't change my settings by default with a new added feature. That's completely bogus.

[rexipus 0]

To reinforce, or perhaps just to reiterate, this addition of 5 C to my nozzle temperature could actually have damaged my print head, because I was already running a nozzle temperature that was already right on the line between what the PTFE liner could sustain, while printing PETG, and what it couldn't sustain without cooking the PTFE liner.

I'd be pretty upset if my liners got cooked, and a nozzle clogged up and ruined a print, and necessitated me taking my print head again just to replace a cooked PTFE liner, just because someone on the Cura team thought it would be really clever to add 5 C to my nozzle temperature without asking me if this was OK. No, it's not OK.

To steal a meme from the social justice warriors (not knocking them), "consent is mandatory!"

[nallath 1,117]

I'd be pretty upset if my liners got cooked, and a nozzle clogged up and ruined a print, and necessitated me taking my print head again just to replace a cooked PTFE liner, just because someone on the Cura team thought it would be really clever to add 5 C to my nozzle temperature without asking me if this was OK. No, it's not OK.

To steal a meme from the social justice warriors (not knocking them), "consent is mandatory!"

 

To play the devil's advocate here; If you want nothing to change, don't update. In this case we could have prevented this change, but there are always behavioural changes, even when no settings are changed. I understand you are annoyed that it's something that directly impacted you, but stating that nothing should change is simply unrealistic.

I do agree that in this case it should have been put in the profiles and not in the default behavior. Then again, we would have most likely put it in every profile with pretty much the same result.

Adding the temperature isn't all that silly as you think it is. If you read the github issue about this (https://github.com/Ultimaker/Cura/issues/1315) the reasons for this are explained.

[ahoeben 1,852]

The issue remains that this is a potentially dangerous change. At the very least this should be flagged in release notes.

[nallath 1,117]

The issue remains that this is a potentially dangerous change. At the very least this should be flagged in release notes.

 

I agree. I will discuss this with "the powers that be"

[mhotze 7]

 

The issue remains that this is a potentially dangerous change. At the very least this should be flagged in release notes.

 

I agree. I will discuss this with "the powers that be"

 

Oohoops. For me a lesson to have a look at the release notes before upgrading. Well... I wonder if I would have noticed. It's this line I think, in retrospect right? "Initial layer printing temperature. The initial and final printing temperature settings have been fine-tuned for higher quality results."

 

I also just found out about the +5deg change when going to Cura 2.4. I noticed considerable oozing after the first prime poop going to the brim, which I did not recall seeing before. I first thought it to be a setting issue. Double checked everything, finally had a look at the g-code, and noticed the +5 deg. Took me a day or so to figure out.