FEATURE REQUIRED: DIFFERENT LINE WIDTH FOR BOTTOM SKIN

[centunesima 0]

Hello Everybody.

I'd been playing with supports settings in Cura for a few days.

I mainly use a 1mm nozzle for my prints. I never managed in having supports removed properly when using a big nozzle.

The issue comes from the fact that a 1mm line is hard to cool down quickly in order to not let it collapse over the supports' roof. The first unsupported layer ends up in being melted with the support's roof. Z-gaps adjustmens do not solve the problem. Thinner lines let the filament to not collapse more easily and therefore the supports to be removed properly.

I thought about a workaround for this: let people set different bottom skin line widths per different skin layer.

For example: By using a 1mm nozzle, the first of the bottom skin layers line width could be set to 0.5, while from the second one it could be set to 1mm in order to save printing time. This should let you have a higher supports removal accuracy since the very first supported layer would be a 0.5 light one, not a 1mm heavy one.

This should help in making 1mm nozzle prints more funtional regarding supports removal. It would influence the quality of bridges and unsupported areas like vertical holes' top parts too.

The line width change could be also be automatically  applied selectively to supported areas only. This feature would help a lot in having neater supported areas. This would work for 0.4 nozzels too, where, for example the supported area skin would be printed at 0.3 line widht instead of 0.4. this would automatically increase the print quality.

At the moment Cura let you only change global skin parameters, except for the very first layer that can be tuned separately.

 

 

 

 

 

Edited February 6 by centunesima

[Slashee_the_Cow 269]

The feature request form is here on the Cura GitHub repo.

 

I do think several of your ideas are misguided though:

 

If you're having trouble with supports collapsing onto the interface you can set Support > Support Top Distance to 0. This will make the supports harder to remove, but will prevent collapses because it'll be printing right on top of the support interface.

 

If you're completely filling an area, thinner lines won't have as large an effect without having the thinner lines spaced out (like when it bridges) because you'll end up with roughly the same weight, just taking longer to print (and the effect to which the lines setting because they're thinner varies significantly by material, i.e. you're never going to get TPU to set before it droops).

 

Bridges already default to using thinner lines spaced further apart in order to set more quickly. Something like this isn't likely to have an effect on covering the top of holes because that's entirely dependent on overhang, which is very different to doing a straight line between two support surfaces and to try and not droop. It would also reduce the quality of the surrounding area because of the large, quick changes in flow rate required.

 

In my experience from doing entire prints at different line widths (but keeping the same width for support interface), mostly with PLA, thinner lines aren't any less likely to stick to the support interface and it can make removing support manually without damaging the model harder because the smaller lines are more fragile.

 

I haven't tested it, but it might be possible (but completely impractical) to create a support blocker, turn it into a modifier mesh to change the line width, position it very carefully where you want it, then copy and paste for everywhere else that needs doing (told you it was impractical).

[centunesima 0]

@Slashee_the_Cow Setting the Z-gap to zero would make the situation just worse. Increasing the density of the roof's surface won't solve the issue. The issue comes from the time needed to cool down a thicker line. 

About the modifiers, I'd love to use them, but cura's ones are really a mess, where you need to split the mesh into nested meshes. Cura should take inspiration from Ideamaker regarding to modifiers and textures. 

I still thinkm the option would be usefull.

I'll try to reach them via form.

Edited February 6 by centunesima

[Slashee_the_Cow 269]

6 hours ago, centunesima said:

About the modifiers, I'd love to use them, but cura's ones are really a mess, where you need to split the mesh into nested meshes.

You can create support blockers and turn them into modifiers using the Per Model Settings tool:

(all the default values of 0 there just mean "not gonna change anything", if you want to actually get rid of walls or top/bottom - which is something you can totally to and just leave infill if you really wanted - you click the dropdown menu and change it from an infill mesh to a cutting mesh)