Support Filament --> PETG for PLA and PLA for PETG and more

Hello all,

because the PLA Support Filament in the Bambu Store is almost always sold out there is also another possibility.

You can also use PETG for PLA and just PLA for PETG. PETG and PLA are printed at similar temperatures, but they can’t combine and so they are very good as a release material.

This wisdom is not from me, but from the Youtube channel of Manbo. In this video it is explained again and shown the settings that should be made. Here is shown “only” PETG as suppoort for PLA. The video is in German. I can if wanted the settings based on the video, again write and translate “let” if the Youtube subtitle is not enough.

I just tested the other way with PLA as separation for PETG and it works just as well. In addition, PLA and PETG is much cheaper than the special support filament from the store.

I hope this information helps some of you, and thanks again to Manbo.

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Hey this is great. I find it hard to follow the settings explanation even with subtitle. Do you have them summarized?

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Ok I will try to write an understandable instruction:

In my example I print with PLA and want to use PETG as a release liner for the support. As I said it also works the other way around.

1) On the “Other” tab, in the “Flush Options” section, disable the “Flush to support objects” function.

2) Then click on “Flushing volumes” in the Filament section to change the flushing volume.

In the video it is set to 800, but I tested it at 300 and it works fine.

This is to safely separate the two types of filament and get a support layer that separates well.

3) Switch to the “Support” tab, where the rest of the settings are made.

  • In the “Support” section, set the support style to “Snug”.

  • In the “Filament for Supports” section, under “Support interface”, select the desired filament for support separation (for PLA prints PETG and for PETG prints PLA).

  • In the “Advanced” section, set the following: (this ensures that the support and the print object are printed through in one and that a smooth surface is created after removing the support).

→ Top Z distance = 0.0 mm
→ Bottom Z distance = 0.0 mm
→ Base pattern spacing = 2.0 mm
→ Top linterface layers = 3 (I only use 2 layers and thus save myself a filament change)
→ Bottom interface layers = 3 (if present)
→ Top interface pattern = Rectilinear
→ Bottom interface pattern= Rectilinear (if present)
→ Top interface spacing = 0.0 mm
→ Bottom interface spacing = 0.0 mm (if present)
→ Support/object xy distance= 0.5 mm

4) (Optional, to save time and material) In the “Other” tab, disable Prime Tower.

*I hope I wrote it understandable. My English is not very good, so I will use a translator. If there are mistakes in the translation please correct and apologize.

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Awesome - thank you!

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As @ jonas91 has tested here in his thread, the whole thing also works with ASA as support for PAHT-CF.

I’m posting this here as a supplement so that we can have all the materials that can be used with each other as support together in one thread if possible, and not have to search for them together in many threads.

Tested were:

  • PETG as support for PLA

  • PLA as support for PETG

  • ASA as support for PAHT-CF

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Has anyone experienced that the prints separate by the support layers?? Test one model with PLA as support separator and its great… then a little more complex model where it seemed like the PETG for the main model was not hot enough or something. The PETG broke apart in every layer where the support was changed to PLA…

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Yeah I have seen similar things when going PLA->PETG. I find I have to purge quite a lot of PETG to properly flush out the PLA to ensure good layer adhesion.

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Works a little too well. I had 2 failed prints because the aux cooling fan blew the part off the support.

I love the ability to do the filament switching, and HATE the increased time and waste. Please make a dual head printer in the future!

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This problem is due to incorrect (too little) “flushing” between PLA and PETG filaments - for this reason, after changing the material, the nozzle is not super clean - part of the next layer is made of a mixture of PLA and PETG and breaks or separates very easily layers.
This is clearly visible when the printout is, for example, white, and the interface layer (made of a different material) is black - all one layer (and if the model is small - even several) is gray, and gradually changes back to white. This is a trace of contamination of white PLA by black PETg (or vice versa)

Set the flush volume from/to pla/petg to 800 - this is enough to blow the nozzle well and not to contaminate the print.

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You can also change the size and amount (mm3) of the prime tower, and flush object infil and support on the “Others” tab.

I am still trying to find the sweet spot to minimize the amount of waste and decrease the print time.

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Yes i found out :slight_smile: the guide i follow Said that 400 was plenty… not….

Another problem is that one of x1c is not able to push out the PETG because pla temp is (i guess …?) and therefore builds a clog… pla grinds and make a ball right before the extruder gear… its then not able to print or retract…. Are you guys running pla at PETG temperatures…?

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Strange. Mine have no problems like that - petg and pla is flushing at ~250’C and works great, my petg (from DevilDesign) is working good even on 220’C like pla (but printing must be sloooow), so no clog or something.

Look at slicer > printer settings > Machine g-code > Change filament g-code:
here is something like that:

; FLUSH_START
; always use highest temperature to flush
M400
M109 S[nozzle_temperature_range_high]

So - nozzle_temperature_range_high should be hot enought, but MAYBY your PLA in this soo high temp is going to be like glass/charcoal and leave some debris in nozzle?

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Make sure that your AMS and slicer has the correct info on the filament. Should be heating nozzle up at the PTEG swap, then cooling down for PLA.

If you have PTEG in the AMS as the support and it is listed as BL Support filament or PLA, then it won’t get to the correct temp.

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I did some tests with using PETG as support for PLA and vice versa. My findings:
using PETG as support for PLA prints works perfectly well. Even with flushing volumes of 280, 'though the PLA print has some PETG remains in the printed object, the PLA object is very strong. In my case the flushing volumes that work good are 280 from PLA to PETG and 346 from PETG to PLA.

On the other hand i had no luck using PLA as support for PETG prints. I used flushing volumes of 346 from PETG to PLA and 480 from PLA to PETG. The printed PETG object will crumble very easy in my hands when applying pressure. So for PETG object with PLA supports the flushing volume needs to be cranked up quite high. PETG contaminated with just a little PLA will result in poor layer adhesion.

For me, with these large flushing volumes, printing PETG objects with PLA supports is a no-go. It simply creates too much waste for the benefits of having clean undersides, compared to simply using PETG as supports in this case.
I will only consider using PETG as a support material for PLA prints, as PETG is way cheaper than the support filaments like Support W or PolySupport, etc.

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For many models it is not a huge problem though if you just use the support material for interface layers.
It will reduce the amount of filament changes by a drastically that reduces the amount of total flush volume and increase print speed.

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I did. I forgot to mention this but i only used the other filament for the support interface layers. The support underneath were printed with the same filament as the main object.

Depending on the model, a big flush volume to make sure no residue is left isn’t a big problem then, something like 800 similar to black->white changes. But with the wrong model, there might still be many different layers that need filament switches and then it might add up.

I can also confirm that PLA does not work as support for PETG. The next layers with PETG after PLA got messed up and my print was destroyed.

PETG might work with PLA just like in the video above, but not the opposite.

I assume that Verbatim BVOH is the best support for PETG. Any other PETG support suggestions?

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Are you sure that flush values from PLA to PETG below 700 is a good idea? I am not worried about PETG to PLA, but PLA to PETG should be higher than 480 or not?

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If you mix PETG and PLA things not gotta work out great, so you will require rather big flush volumes for things to work out smoothly, else the material might get very easy to break on that entire layer.