Switching to PTEG from PLA and First layer calibration?  

RE: Switching to PTEG from PLA and First layer calibration?

Textured sheet is thinner than smooth, I'd recommend re-running the wizard. There's no need for anything special, you will be fine by just unloading PLA and loading PETG, PLA will be flushed out of the nozzle pretty easily since PETG prints at higher temperature (240). First layer calibration wizard has PETG as one of the options, no struggle there either. PETG does not like to be squished as much as PLA, keep nozzle a tiny bit higher than you are used to with PLA. Clean your textured sheet properly with dish soap and rinse with hot water, then dry thoroughly, and do not touch the surface. Don't forget to change filament profile in slicer 😉 

RE: Switching to PTEG from PLA and First layer calibration?

@crawlerin

Why clean with soap? Alcohol is not enought? 😀

RE: Switching to PTEG from PLA and First layer calibration?

@crawlerin

If I switch to flex material? Is it easy as change to pteg? Thank you 😀

RE: Switching to PTEG from PLA and First layer calibration?

Posted by: @crawlerin

Textured sheet is thinner than smooth, I'd recommend re-running the wizard. There's no need for anything special, you will be fine by just unloading PLA and loading PETG, PLA will be flushed out of the nozzle pretty easily since PETG prints at higher temperature (240). First layer calibration wizard has PETG as one of the options, no struggle there either. PETG does not like to be squished as much as PLA, keep nozzle a tiny bit higher than you are used to with PLA. Clean your textured sheet properly with dish soap and rinse with hot water, then dry thoroughly, and do not touch the surface. Don't forget to change filament profile in slicer 😉 

Many thanks for your response!

RE: Switching to PTEG from PLA and First layer calibration?

I use only the smooth sheet so I use a layer of gluestick on the heatbed when I print PETG. You need to be careful while using the smooth sheet because PETG sticks really well on it and it might pull the surface apart.

Other than that I am using the custom gcode that people have posted here in the forum. This custom gcode performs mesh bed leveling with a bed temperature equal to the first layer bed temperature(e.g. 85C for PETG). This means that your MINDA will heat up differently than PLA (bed temperature 70C) and produce different results during mesh bed leveling because of the fact that MINDA doesnt have temperature compensation. In the custom gcode I set the mesh bed temperature on 70C for all materials.

RE: Switching to PTEG from PLA and First layer calibration?

@geoper2

Thank for explained more technique for pteg. Can you please explain more about "This custom gcode performs mesh bed leveling with a bed temperature equal to the first layer bed temperature" I still cannot understand. 🙂

And what is bad point about using normal prusa preset? why need more complex modification?

if i want to ask about using flex, can you explain here? Or I should post new topic. 🙂

thank you

RE: Switching to PTEG from PLA and First layer calibration?

I only use the smooth sheet and when I changed the filament to PETG I saw major changes in mesh bed leveling. This means that the first layer was way off, the nozzle was too high and the first layer failed. I found that this happened because of the difference in the temperature of the heatbed while mesh bed leveling.

If you look in the link below you will see that because of the fact that the MINDA sensor does not have temperature compensation it produces different results when cold from when hot. Because of this people have been reporting that they add custom g-codes to warm up the MINDA before performing mesh bed leveling. This ensures that your mesh bed leveling will produce the same results everytime. You could use @rick-m12 custom gcode if you would like. The normal Prusa preset will heat your bed to "first_layer_bed_temperature" which is different for each material and will produce different results everytime. If you use the custom start gcode the bed will go to a specific temperature and produce the uniform results.

https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/brand-new-prusa-mini-z-needs-to-adjust-on-every-new-print/paged/2/

RE: Switching to PTEG from PLA and First layer calibration?

Posted by: @geoper2

I only use the smooth sheet and when I changed the filament to PETG I saw major changes in mesh bed leveling. This means that the first layer was way off, the nozzle was too high and the first layer failed. I found that this happened because of the difference in the temperature of the heatbed while mesh bed leveling.

If you look in the link below you will see that because of the fact that the MINDA sensor does not have temperature compensation it produces different results when cold from when hot. Because of this people have been reporting that they add custom g-codes to warm up the MINDA before performing mesh bed leveling. This ensures that your mesh bed leveling will produce the same results everytime. You could use @rick-m12 custom gcode if you would like. The normal Prusa preset will heat your bed to "first_layer_bed_temperature" which is different for each material and will produce different results everytime. If you use the custom start gcode the bed will go to a specific temperature and produce the uniform results.

https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/brand-new-prusa-mini-z-needs-to-adjust-on-every-new-print/paged/2/

THis is very interesting, I have not run into this problem yet. I have had pretty consistent prints without first layer issues. I don't do many back to back prints so I don't know if that is a factor.

RE: Switching to PTEG from PLA and First layer calibration?

@kevman

Yeah it is a factor. There's some slight difference when printing from "hot" vs "cold" printer, for some reason. Especially with PETG, it can mess second and further layers of solid infill because that thing is pretty sensitive at speeds it prints (80 mm/s by default). If it's too low, it won't stick properly and will stick to nozzle instead of being pulled by previous layer, making clumps. If it's too high, you will have holes and filament blobs on sides of the nozzle.

RE: Switching to PTEG from PLA and First layer calibration?

@geoper2

thank you so much 🙂

RE: Switching to PTEG from PLA and First layer calibration?

@geoper2

I see, this gcode is heating minda to proper temperature and then minda will get right measurement the operating mesh bedding with every material. And then it heat to material temperature to perform printing.  Right? 🙂

RE: Switching to PTEG from PLA and First layer calibration?

@crawlerin

what temp should minda get? I see some user said 35 c. Is it this temp?

thank you

RE: Switching to PTEG from PLA and First layer calibration?

@atomleef

Yeah exactly the mesh bed leveling is performed with a specific temperature every time no matter the filament. Then after mesh bed leveling the printer will reach the appropriate temperature for each filament and according to your Slicer settings in order to start printing.

RE: Switching to PTEG from PLA and First layer calibration?

@atomleef

Yes people say this for the PINDA probe in mk3s and benji here in the forum performed a test and saw that after a certain amount of time under heat the sensor performs uniformly. But its uncertain at what temperature it reaches.

RE: Switching to PTEG from PLA and First layer calibration?

@geoper2

thank you

RE: Switching to PTEG from PLA and First layer calibration?

@geoper2

if the proper minda temperature should be around 30 c degree, the for me it not much worry because my average temperature is 30-35. right 🙂
thank you

RE: Switching to PTEG from PLA and First layer calibration?

How do you measure it? MINDA does not have temperature sensor, compared to its bigger cousing PINDA 2 🙂  

RE: Switching to PTEG from PLA and First layer calibration?

I think you cannot measure it, that's why I said its uncertain at what temperature it reaches. The certain thing is that after an amount of time under heat it starts performing uniformly.