What's the use of different supports

[Patriboom 1]

Hello everyone,

 

I would like to understand why in Cura, we have those optionnal support for printing.

What is the mecanic use of (how does it help to piece to stick better on the plateau):

- Skirt  ?

- Contour  ?

 

About Raft, I know and I use it sometime

1)  when the piece has a small base, to make sure it sticks good on the plateau;

2) when the surface is very big, to make sure the piece will not present any « bubble » in its attachment to the plateau.

 

 

Complementary:

a) Why « skirt » is set as default.  I can see no use of that, but pure waste of filament  ?

b) How to change the default value without creating a new profile ( Cura 5.4.0 under Linux - appImage) ?

 

Thanks.

[Slashee_the_Cow 279]

This is build plate adhesion, support is the stuff that gets built up so that parts of your model that extend outside its original footprint (or vertical gaps) doesn't just fall straight down.

 

A skirt is there to make sure the material gets flowing correctly and gets any dust or crap off the nozzle in a throwaway bit instead of the start of your model.

 

Brim greatly helps adhesion, because the plastic adheres far better to itself than the plate, so in order to dislodge it in anyway not only do you have to its so-so grip on the build plate, but also each line of the brim's grip on the build plate, because the whole thing will only come off as one (to a point anyway, too much brim is just wasted material, but even ten lines can be useful).

 

Rafts aren't designed for big objects (it's a massive waste of filament), the idea you're supposed to keep the build plate clean so if something causes a "bubble" it's part of the extrusion process, not something on the print bed (and also why you have multiple layers of skin, so it evens out in the end.

You are correct in that they can be used if the base of an object is very small, because then even a brim might not be enough to hold it, and as I said about brims, the material grips far better to itself than the build plate.

They're not used anywhere near as much as they used to be though because printers and software have gotten a lot better over the years and adhering to the build plate is a lot better than it used to be. They're also a lot more hassle to remove than a brim and more likely to leave scars where the object was being held up.

 

As for your questions:

a) As explained earlier, it's to make sure the material is flowing correctly and getting crap out if its system. It's also a great time to hit the stop button if for some reason the skirt isn't adhering.

b) Not in an AppImage. I think it's possible (never tried) in a Windows/Mac installation because you can actually edit the files the program installs (which include the quality profiles), but the way an AppImage is packed, you can't. You could just create a custom profile where the adhesion method is whatever you want it to be by default and the rest will just carry over from the profile you based it on, Cura should load with the last used profile automatically set.

Edited November 21, 2023 by Slashee_the_Cow

[Patriboom 1]

On 11/21/2023 at 12:46 AM, Slashee_the_Cow said:

As for your questions:

 

Thanks a lot for all this.