Sunlu PETG color changes variations during print  

RE: Sunlu PETG color changes variations during print

Bad filament... I would return it. 

RE: Sunlu PETG color changes variations during print

i think you are right. This is a new print that I started after letting it dry for 6 hours at 70C.

RE: Sunlu PETG color changes variations during print

Posted by: @sceiler

i think you are right. This is a new print that I started after letting it dry for 6 hours at 70C.

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I can't tell the size from the photo but long narrow tubes like this generally require slowing down the print or increasing the part cooling fan. 

RE: Sunlu PETG color changes variations during print

Posted by: @sceiler

i think you are right. This is a new print that I started after letting it dry for 6 hours at 70C.

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I can't tell the size from the photo but long narrow tubes like this generally require slowing down the print or increasing the part cooling fan. 

RE: Sunlu PETG color changes variations during print

250x6.53mm

That was the end though and I wonder why it didn’t happen earlier. I am not even sure what exactly happened that would make it look like this 

Posted by: @hyiger

 

Posted by: @sceiler

i think you are right. This is a new print that I started after letting it dry for 6 hours at 70C.

---

I can't tell the size from the photo but long narrow tubes like this generally require slowing down the print or increasing the part cooling fan. 

RE: Sunlu PETG color changes variations during print

Posted by: @sceiler

Hi everyone,

I’m testing a new Sunlu PETG filament and running the latest firmware 6.4 with the current PrusaSlicer. The print uses the Prusa Sunlu PETG profile with mostly default settings. Nozzle and bed temperatures are 250 °C and 85 °C, stable throughout the print.

I’m seeing noticeable color variation in the finished part. The filament was dried for about two hours right after unpacking and is currently being dried longer to rule out moisture.

Besides moisture, what other factors could cause this kind of color inconsistency?

https://imgur.com/a/WWtXd0F

Given that this is PETG and should be shiny but your print appears to be matte in the imgur photos, I wonder if you aren't running it hot enough so it isn't melting thoroughly. Does the layer adhesion seem less than expected? (Another indication of not melting thoroughly.)

Though the regular banding (that gets wider when not as much filament is being used) might indicate process issues manufacturing the filament...

RE: Sunlu PETG color changes variations during print

The exact PETG is called Rapid Matte PETG. They claim it can be printed with 255-270 for 300-600mm/s. However I am not sure it would reach that fast given the rather compact print so I opted to leave it at 250C

Posted by: @sembazuru

Posted by: @sceiler

Hi everyone,

I’m testing a new Sunlu PETG filament and running the latest firmware 6.4 with the current PrusaSlicer. The print uses the Prusa Sunlu PETG profile with mostly default settings. Nozzle and bed temperatures are 250 °C and 85 °C, stable throughout the print.

I’m seeing noticeable color variation in the finished part. The filament was dried for about two hours right after unpacking and is currently being dried longer to rule out moisture.

Besides moisture, what other factors could cause this kind of color inconsistency?

https://imgur.com/a/WWtXd0F

Given that this is PETG and should be shiny but your print appears to be matte in the imgur photos, I wonder if you aren't running it hot enough so it isn't melting thoroughly. Does the layer adhesion seem less than expected? (Another indication of not melting thoroughly.)

Though the regular banding (that gets wider when not as much filament is being used) might indicate process issues manufacturing the filament...

RE: Sunlu PETG color changes variations during print

I have used the Sunlu Rapid Matte PETG in white with perfect results but I have a diamondback nozzle (0.4mm) and have not reduced the standard PETG temperature, I also am not using the HF profile just the normal nozzle profiles. Most people find they need to reduce the temperature with this nozzle so maybe you need to raise it.

Sorry I cant see imgur as it is currently blocked in the UK.

Also typically PETG of any sort needs to be hot enough to melt into the previous layer and if cooled too rapidly results in weak layer adhesion. Small diameter tubes tend to be very problematic as the heat builds up and causes the tube to melt and warp, you could try slowing the non print moves and spacing the tubes so the print head takes longer to travel between tubes giving them time to cool. I have always found petg is strongest if hot and given time to cool. Normally it should be glossy but in this case it is more of a satin finish with this filament and when printed correctly it has a very nice finish.

RE: Sunlu PETG color changes variations during print

Always take manufacturer's speed claims with a grain of salt. If they say (for example) 300 - 600 mm/s I would start with 450 mm/s and work my way down. So basically 450 mm/s with a 0.4mm nozzle and 0.2mm would be a max volumetric flow of 40 mm^3/s. I would then run a volume flow test at 260° between say 25 - 50 mm^3/s. Then what ever I come up with, for example 35.5 mm^3/s I would subtract off 20% and make it 30mm^3/s