Different infill for separate models?

[stere0atypical 0]

If I have 2 separate models to be made in the same print, is there a way in Cura 3.1 to set the infill as different values for each? I want to print two models at once, but want one to have 100% infill and the other 10%.

 

Thanks

[Nicolinux 285]

Sure, it is called "Per Model Settings"

Check out this guide:

https://ultimaker.com/en/resources/52004-adjustment-tools

[smartavionics 288]

BTW, 100% infill gets printed as skin so if you really want it to be infill, use 99%.

[yellowshark 148]

Interesting; as someone who prints at 100% infill most of the time I am wondering what the difference is between skin and 99% infill, is there any real difference? My focus would be on structural strength.

[ahoeben 731]

The difference in a layer that is all bottom layer and a "normal" layer that has 99% infill is that in the latter the walls and bottom/top layers are "drawn" separately from the infill, whereas in the former case it is all printed in one go.

[smartavionics 288]

3 minutes ago, ahoeben said:

The difference in a layer that is all bottom layer and a "normal" layer that has 99% infill is that in the latter the walls and bottom/top layers are "drawn" separately from the infill, whereas in the former case it is all printed in one go.

Really? In the case of 100% infill, each layer gets printed just like a top/bottom layer, i.e. walls first and then skin. There is no option to print skin before walls but this was actually talked about recently as a possible means to improve wall adhesion on the first layer (myself, I don't believe that is a good solution but that's another topic). In the case of less than 100% infill, the walls may or may not be printed before the infill depending on the user option. I do not understand what you mean by "all printed in one go" above.

[ahoeben 731]

Sorry, I did a bit of a shitty job explaining.

 

Nothing really changes about how the walls are printed. The main difference afaik is for walls that don't go straight up. Slanted walls normally get a bit of top or bottom skin added, to ensure there is enough thickness in all directions. Think of printing the top couple of layers of a dome without infill, where each layer gets smaller increasingly quickly; without additional "top skin" printed on the inside of the inner walls, there would not be enough wall to put the next wall on. Those pieces of top layer would be printed separately from the wall and separately from the infill in a "normal" 100% infill, but when everything is printed as bottom layer then those pieces are merged with the "faux infill".

 

At least, that's what I understood. But you know more of the innards of CuraEngine than I do.

 

PS: little unknown fact: you can also print at more than 100% infill.

[smartavionics 288]

Hi @ahoeben, thanks for the longer explanation - that makes sense.

 

I would have thought that printing with more than 100% would make the resulting model bulge!

[ahoeben 731]

Yes, printing at >100% infill will effectively cause overextrusion. But setting infill to 100.01% does not trigger the "if infill is 100, use only bottom layers" thing and gives you only 0.01% over-extrusion.

[ultiarjan 1,162]

On infill, as a side note, be aware some cura profiles, i think only on the UM3, have a thicker infill line setting, which you only see when you open the extra advanced settings. This results in thicker but less dense infill, and with some speed settings into under extruded infill, making a weaker print.

 

I personally think this is a pretty bad default, specially combined with some of the really high default speeds for infill.

 

Edited January 6, 2018 by ultiarjan

[smartavionics 288]

19 minutes ago, ultiarjan said:

I personally think this is a pretty bad default, specially combined with some of the really high default speeds for infill.

 

And it's going to get worse when the variable layer height feature becomes available unless Cura is given a means to limit the layer height (or adjust the infill speed, etc.) so that the hotend+extruder throughput limit is not reached. As we know the product of line width, layer height and print speed can't be a greater mm^3/S than the hotend+extruder can deliver for a given temp/material combo.