Extra support around holes for fasteners

[spepin 1]

Hi,

When printing an object with, say 20% infill, is there a way to adjust the thickness of the material surrounding a hole independent of the outside wall thickness? For instance, I want to include some holes for fasteners. I'd like a bit more solidity in the area around the holes to better support against crushing. Is there a way to design this with a thicker wall than what is normally printing around the perimeter of the object?

[eldrick 65]

Cura and other slicers use the same external wall thickness around holes as around the outside.

I'd love to hear of a better solution, but the only method I've seen mentioned is to make several parallel very small (fraction of a mm) holes surrounding the hole you want to reinforce. The tiny holes will each get their own wall, and those will merge around the main hole for a thicker wall around it.

(I haven't personally experimented with this.)

[yellowshark 153]

I have not tried this but another option, although @eldrick 's point is a good one, would be to use one of the add-ons either tweak at Z or another one whose name escapes me, that lets you change the settings at particular Z heights and change the infill to 100% for the layers that the hole(s) "sits" in.

[JVorders 0]

I'd love to see a feature in Cura that can independently control the thickness of a wall section around a hole. I've noticed that screw heads tend to leave an indent in the material over time and although that seems to be the case on all the different manufacturing methods we've tried (machined PVC, Nylon SLS and PLA/ABS FDM) I think extra material around a hole would help the longevity of the fixture parts we print on our U3.

[kmanstudios 1,120]

On 3/10/2016 at 12:49 PM, yellowshark said:

I have not tried this but another option, although @eldrick 's point is a good one, would be to use one of the add-ons either tweak at Z or another one whose name escapes me, that lets you change the settings at particular Z heights and change the infill to 100% for the layers that the hole(s) "sits" in.

Would that not be accomplished by using the 'infill mesh option'?

[yellowshark 153]

And of course the simplest method is to use 100% infill not 20%

[spepin 1]

16 minutes ago, yellowshark said:

And of course the simplest method is to use 100% infill not 20%

Maybe it's the easiest, but for most parts, especially very large pieces, 100% isn't necessary, and sometimes isn't even feasible.  Also, sometimes 100% leads to other problems.

[yellowshark 153]

Well it all depends on what you do. All I am saying is that 100% will solve your problem; which arguably means it is necessary. Most of my work is engineering where strength is important, even when prototyping if that incudes "form and fit"; so 90% of what I print uses 100%, which on the smaller parts is sometimes is faster to print that say 20%. And yes if I have a piece that is at least 75% of the bed space I will try to avoid 100%. Personally over 4+ years I have never had an issue with 100% infill so I am wondering what you have experienced.

Another solution is to consider "inserts for plastic" In fact I think @eldrick has been using these for a long time for his foil handles. These are metal threads that you insert into the plastic so you can screw in bolts securely. I managed to get a sample set for free from one of the manufacturers/distributors and they seem to work very well although I have not tried them in earnest in production yet; having said that although I cannot remember I suspect I used 100% infill when I tried them.