Different wall thickness for "inside" walls?

[tier777 0]

Is it somehow possible to have a separate wall thickness for walls on the inside of my model?

 

I am currently preparing to print a threaded piece with a fairly large diameter and hollowed out the middle of the piece to save material and printing time. However, as I have set a wall thickness of 3mm to make my threads more robust, Cura slices the walls around the hollow space also 3mm wide, which defeats the whole purpose of hollowing out that space in the first place...

 

Any ideas or suggestions?

 

Cheers,

 

Oliver

[gr5 2,268]

I think you will find that those 3 walls print faster than anything else.  Faster than infill, etc.  Going from 2 to 4 walls may increase print time by 10%.  Going from 20% infill to 10% infill may cut print time almost in half.  Maybe those 3 walls aren't a problem around the inner air shaft.

 

 

[tier777 0]

21 minutes ago, gr5 said:

I think you will find that those 3 walls print faster than anything else

Well, it's more than just 3 walls... As I wrote, it's 3mm worth of wall lines (actually: 3.2mm - I had simplified that in my previous post), i.e. at 0.4 mm line width, that's 8 wall lines, where I was hoping to somehow get away with only 2 (i.e. 0.8mm wall thickness)...

 

The difference between the Cura estimates for print time between the model with hollowed out middle and the one without (both using 25% infill) was actually zero in one of the test slices I did. Seems the slower print speed of the additional walls completely negated the gain of doing less infill... And all that while using up even more material...

 

FYI: The "air shaft" at the center of my model is actually more TicTac-shaped (or should I say "minion-shaped" 😉 ). and has an inner diameter of 3cm and a height of ~6cm.

[yellowshark 153]

It would be interesting to see what the result would be if you reduced the number of walls to 2 and increased the infill to say 40%. I am not saying you are wrong but I have always used 2 walls and tailored the strength of the part by the density of the infill. I quite often print at 100% infill and have found on certain sizes/geometries that 100% infill is faster than using a lower density - important to us as print time is by far the major influencer on pricing whereas material has a small influence.

 

 

.Also you do not say what print speeds you are using for infill and for walls. If they are all the same it surprises me that you are not seeing a gain but maybe my brain is missing something.

[Framar 38]

The solution is to create another geometry (you can create a support blocker) and change the per model setting to set a 100% infill. This will give you the extra walls you are looking for.