PETG and PLA as support  

RE: PETG and PLA as support

I think the theory is that the time taken in filament changes is enough for the nozzle to reach temps for the filaments.

My main reason for not trying this is that I've definitely found that PLA, PETG and TPU all have different optimal zOffsets.  In fact I have separate sheet profiles for them:  Spla, Spetg, Stpu, Tpla, Tpetg and Ttpu

I'm not sure if you had a mixture of PETG and PET filaments you'd get good first layer adhesion if part of the first layer was PETG and part was PLA since in doing the zOffset calibration on the same sheet with the two filaments, I got different numbers that worked best.

Maybe someone else with more experience could chime in.

RE: PETG and PLA as support

Dim question, why would you want to do this?

RE: PETG and PLA as support

@towlerg

Good question.  I guess if you don't want to pay for pva or bvoh?

It's still going to be hard to remove from some places where as with soluble material you just drop it in a bucket of water.

RE: PETG and PLA as support

@ssill2

Sorry I didn't phrase that very well, why not just use PETG or PLA? Surley theres not enough difference in price to be worth the hassle and neither material has any advantage when used for support.

RE: PETG and PLA as support

@towlerg

From what I've seen, people printing in PETG wanted an alternative to printing the supports in PETG since they can be difficult to remove.   I've experienced this myself.  I printed a mask in PETG and in some cases, it was difficult to remove them.  I think that PLA doesn't bond super well to PETG but will support it during the print.  I believe the OP was asking about this.   Yes, PETG and PLA have different temps, but so do the soluble support materials like PLA and BVOH.   Using the stock profiles for BVOH provided in the slicer it lowers the nozzle to 195 and up to 230-240 for generic PETG.   The period of time taken to switch out filaments is more than enough time for the change.  I watched it do this a few hundred times when printing in PETG and BVOH.  down 195, up to 240 rinse and repeat.  it spends a bunch of time on load of the filament and unload and this is ample time to allow the nozzle to come to temperature.   But if you have the mmu,  I'm not sure why you wouldn't just print in PLA or BVOH instead of PLA, unless it was a cost thing.  At the end of the print being able to just dunk the print in a bucket of water and have the solubles loosen up and dissolve is much better than having get the pliers out.  I guess it just depends on how much support material you have and how engrained it is in your print.  in some cases solubles would be the only option.

RE: PETG and PLA as support

@ssill2

"an alternative to printing the supports in PETG since they can be difficult to remove" couldn't agree more.

Thanks for taking the trouble to explain so comprehensively.

RE: PETG and PLA as support

@towlerg

Sure.  But like I said, if you have an mmu, why not just print with BVOH(the one recommended by prusa)?  For me the main compatibility between the different materials is more the zOffset diff.   When doing first layer calibration, PETG needs to be further away from the build plate than PLA, TPU, etc.  It's why I have the separate sheet profiles.  So if you had a first layer with both materials I could see issues getting adhesion on the first layer.

The other thing with the soluble supports of course is you just dunk the thing in water at the end....   No pliers or cut up fingers!

RE: PETG and PLA as support

Sorry for a thread Necro but no one replied to you.

I avoid BVOH because I want to avoid adding (more) microplastics to our water.

By using PETG or PLA for supports I hope to get the same clean support surfaces as BVOH and recycle the supports like my other supports.