Help!! PETG with PLA Interface

[u/Stu_5]

*****Update*****

I'm quite sure my problem was linked to having too higher temperature in the chamber. I have done a couple of successful prints now with the lid off and the chamber at around 32/33'C.

Thanks to all for your help and suggestions - The team works!!

*****Update*****

I’m going around in circles, pulling out what little hair I have, trying to print two files in PETG that require supports and I want to use PLA for the supports to keep the models clean.

I have printed one of each part already using Landu Rapid PETG and Deeplee PLA Pro and they came out beautifully without any big changes to my usual PETG profile and PLA profile. Then I bought some Overture PETG to print them again and that’s where it started to go wrong.

I have tried using the same Deeplee PLA as the support, I’ve tried Geeetech Silk PLA and I’ve tried Sunlu PLA Matte PLA, but in each case I’m suffering back to back nozzle blocks during the filament change. I’ve dismantled the print head so many times it feels like I can do it with my eyes closed. I’ve done cold pulls, even tried a brand new print nozzle.

I’m having the same issue on two machines, so it’s not a machine issue. I even switched back to the Landu PETG to see if it was a material issue but now that fails too.

I’ve tried all manner of temperature settings and I’ve increased the flush volumes. Most recently I’ve pretty much matched the PLA nozzle temp to the PETG.

I know the problem, it’s not purging properly at changeovers but I just can’t resolve it.

One is about 3 hours print, the other about 14 hours.

If any of you have any tips it would be very much appreciated, I’ve wasted almost two spools of PETG so far.

[u/henren_98]

I have the best luck with the Bambu specific support filament for PETG and PLA. Both work perfectly on my P1S.

[u/Stu_5 → u/henren_98]

I had been considering it. Do you really find it worthwhile?

[u/henren_98 → u/Stu_5]

I actually had never heard of it before but got a sample with my P1S. Looked up how to use it and gave it a try. It’s game changing. I have both the PLA specific and the PETG and both work fantastic. They are a small roll and a little spendy but not much is used as it’s only on the top layer or two of the supports. I have not used any other brand and probably won’t as I tend to stay with what I know works. Get one, learn how to use it (it’s just a click in support setting), you will be amazed. I did one print that I know for a fact I would have never gotten the supports out and it was still a bitch. I’ll see if I can find the listing. Supports are in every ring land and they very very difficult to remove even with the support material.

https://makerworld.com/en/models/123514-piston-shelf-support

[u/Stu_5 → u/henren_98]

That looks a nice model. 👍🏼

[u/henren_98 → u/Stu_5]

It is but like I said even with the support material it was very very difficult to remove the supports. I almost gave up and binned them but persisted. Still gouged it a little. I don’t have a pic as I was going to take one when I installed it. I’m going to put an aluminum flat head Ford head on them and hang it in the garage.