PT100 temp question



  • As long as I have been using both of my Duet equipped printers (with PT100) I have had issues with layer adhesion and structural failure with both PLA and PETG. The past week I tried printing Solutech PLA from 225 to 235, and even 240 first layer. The parts are crazy strong and there are no signs it's printing too hot. This seems like the way it was meant to print all along. So now I question if the actual temps are a lot lower than indicated. But I've seen DC say that PT100 sensors are accurate to within half a degree. So I'm a bit baffled. I can just keep printing 10 degrees higher than the highest recommended temps, but that seems questionable. I will be testing PETG and Ryno soon at similar temp increases over recommended. One of my printers was a WiFi, and the other is a Maestro. Soon they will both be Maestro so I can move the WiFi to the new MPCNC.



  • Are you by chance using a steel nozzle instead of brass? Steel nozzles generally need extra temperature due to low thermal conductivity.



  • @3dmntbighker It's kind of impossible to give any sort of informed opinion without knowing anything about the geometry of your hot end. But are you using part cooling and is that perhaps a bit too aggressive?

    Regardless of that, if you've found you get better results using a higher temperature, then stick with it. I have the opposite problem and frequently find that I get better results by printing a few degrees lower than the recommended minimum temperature for any particular filament. The important thing to remember is that the temperature of the filament as it exits the nozzle, may differ significantly from the temperature at the measurement point in the hot end. So simply find what works best for you, on your machine, and ignore what the books (or other people) say.



  • @jamesm said in PT100 temp question:

    Are you by chance using a steel nozzle instead of brass? Steel nozzles generally need extra temperature due to low thermal conductivity.

    Yep, I am.



  • @3dmntbighker said in PT100 temp question:

    @jamesm said in PT100 temp question:

    Are you by chance using a steel nozzle instead of brass? Steel nozzles generally need extra temperature due to low thermal conductivity.

    Yep, I am.

    I'm using hardened steel here as well and I tend to use temps about 10c hotter than otherwise recommended for the material in order to get good results. PT100 as well.



  • PLA manufacturers (err, basically natureworks LLC) have been pushing the extrusion temperature higher and higher in an effort to increase temperature resistance. You might also notice that these PLAs that require higher temperatures no longer smell like maple syrup when you use them. This is the progress of the chemistry of the PLA. It seems to essentially all come from one manufacturer (the raw PLA pellets). There are several different forms of the raw PLA, the newest of which will likely have the highest extrusion temps.



  • @bot said in PT100 temp question:

    no longer smell like maple syrup when you use them.

    I have definitely noticed this. They also seem less shiny and less brittle.