I have heard that on the Sparkx i7, or any multi-color printer, that you can use PLA and PETG together, one for the main model and the other as the support material. The idea is that since these two filaments don’t stick to each other very well, that they make a good pair for printing supports in one filament that break off easily on a model of the other filament. So, I decided I would try it.

I used one of my models, a scorpion, since on this model, removing supports without breaking the legs is delicate process.

https://www.crealitycloud.com/model-detail/scorpion-printing

The supports are underneath and around the legs and when removing the support the legs can break off.

As a control, I printed the Scorpion in its normal size and everything in PLA. The supports were taken off without much trouble. I did have some good support related print settings as shown below. Link to Youtube

Layer height .20

Wall loops 2

Infill, type 15%, Rectilinear

Supports Enabled, Tree(auto)

Top Z Distance .4

Minimum Support Contact Area .64

I then reduced the model size slightly to help with the longer print times of using two different filaments. Next, I added a PETG as a second filament along with my existing PLA filament.

In my support settings I went to switch supports to use the PETG filament and I was surprised to find that I didn’t have to switch between filaments for every layer, only for the interface layers-where the supports meet the body of the model. This would save time and filament. So, I changed the print settings to be PETG for ‘Support/raft interface’.

When I changed the setting under ‘Filament for Supports’ and the option for ‘Support/raft interface’ to be the PETG filament. I received the following prompt to adjust my top z distance to 0, interface spacing to 0, use concentric pattern and disable independent support layer height.

I click on Yes. Also, note that I temporarily changed the ‘Support/raft base’ setting to be PETG but Creality Print basically said “Really, I don’t think you want that”. So, I left the ‘Support/raft base’ setting as ‘Default’.

Here are my settings in Creality Print for supports to use PETG.

Slicing looked like the first photo below. The second photo is the actual printed model. The white is the PETG support interface layer whereas the black is the model itself as well as the supports before the interface layer. Note: the nozzle temp for the PETG for this filament is set at 250 and print bed at 70 (Celsius). For the PLA filament it was 220 and 50 (Celsius).

Finally, I sent the print job to the printer for about a 3 hour print. When finished I tried to remove support. This did not go well.

I noticed that sometimes the PETG broke away easily from the PLA but only sometimes. It did stick together in some instances.

I also noticed during the print that the print bed was at 60 degrees Celsius while printing PLA and had not cooled down during the PLA printing after the change from PETG. Maybe nozzle temp did not fully adjust with each filament change.

I suspect that as the printing was too hot for PLA that it caused my model to become stiff and brittle. When I removed the supports, the legs broke off and the body of the model split apart easily.

To double check the cause of this, I printed the model again, all in PLA but with the same settings using the previously suggested changes to supports (top z distance to 0, interface spacing to 0, use concentric pattern and disable independent support layer height).

It did not split and break as easily, but the body did break apart and supports did stick too well and the legs broke off and the model body split as well. So, the support settings were at least partially at fault.

So, I changed the support settings back and reprinted all in PLA, just to make and it was the support settings and this last time I was again able to remove the supports without breaking anything.

Rather than reprint without these settings but with the two filaments, I determined based on my print of the two filament, that the PETG did stick too well to the PLA. This was perhaps affected by the many different spots where the two filaments interfaced, rather than it being a flat surface where they interfaced -- and in the case of a flat surface PLA supports remove fairly easily so not need for special treatment. Also, possibly the brand and colors affect how well the two filaments stick together.

My conclusion was that it was not really all that helpful, at least on a complex model. Try it yourself, if you are so inclined, and comment below on your results.

PLA Model with PETG Supports-Trial