Any Concerns Switching Materials? (PLA > PETG > PLA > ...)  

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

I always do a nozzle clean when switching from high temp filament like PETG to lower temp like PLA. If any filament residue gets left behind, it won't melt out at lower temps and can cause a partial clog. I use cleaning filament that will melt out all the PETG at 265C but will still melt out at PLA temperatures. A cold pull is also recommended.

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

Thanks for the reply.  What is a cold pull, and where does one get cleaning filament from?

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

I don't have cleaning filament, but when going from a higher temp filament to colder temp filament I do a cold pull. I use the lower temperature filament but use the higher temperature filament max temperature as the high temp for the cold pull. So, from going from ASA to PETG, I do a cold pull with PETG filament, but heat it up to 260 C, push the filament to start extruding, cool down while extruding to about 200 C or where it gets difficult, then cool down to about 130 C and do the pull.

https://help.prusa3d.com/en/article/cold-pull-mini_126399

Regards

Mark

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

Posted by: @canardiain

Thanks for the reply.  What is a cold pull, and where does one get cleaning filament from?

I use eSun cleaning filament ordered off Amazon, but there are others available depending on where you are located. The main thing is that the stuff is both very sticky (good for grabbing crud) and melts over a wide range. You don't have to use cleaning filament, but I sure recommend it.

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

Thanks for the replies!  I found this information regarding the Cold Pull, but it's for the other larger printer:

https://help.prusa3d.com/en/article/cold-pull_2075

Am I right in that PLA > PETG would not require a Cold-Pull, but then when going from PETG > PLA, that's when a Cold Pull would be good to perform?

I had visions of being able to freely switch back and forth between these materials but sounds like that's not really a good idea.  Do most people just end up sticking with one material and always print with just that?  I've had other printers but tended to always just stick with one material since they were so finicky.

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

@canardiain

My previous post had the link for cold pull on the Mini. Since it has the Bowden extruder, it is different as you have to remove the fitting and the tube. It does not seem like a big deal although you should not over tighten the fitting when it goes back on.

A cold pull is usually needed when going from hotter to colder, so yes from PETG>PLA. It is not always needed going the other direction, but if the extrusion does not look right, I do a cold pull then also. When the filament loads and extrudes the first amount I look at it as it is extruding. If it doesn't look smooth, large enough, or has gaps I might do a cold pull.

I change up filaments all the time. I haven't tried cleaning filament, but as you can see there are many that recommend it.

I've only answered what I do. I have no idea what the many other Mini owners do, and just reading this forum is a very poor poll. Most people in forums post problems. For each person that posts, there may be 100 others that have everything working and never post. So, I would never try to say what "most people" do. Of course there are posters like @bobstro who mostly help others with their problems. They probably have a much better perspective than I do.

Regards,

Mark

RE: Any Concerns Switching Materials? (PLA > PETG > PLA > ...)

@canardiain

I personally don't do a cold pull every time I switch from hotter to colder materials. I've printed nylon last week and switched to PLA afterwards without any problems.

BUT knowing how to do a cold pull is always useful. I usually do it when as mark said the extrusion doesn't look smooth. 

I'd say doing a cold pull in between is optimal but not mandatory, I get away without all the time. But it has a chance to clog up a bit.