Boolean Subtract Offset error?

tom_auger

Hello, I'm encountering what appears to be an error calculating an offset (for 3D printing) in a boolean subtraction of two solids.

Offset All produced an error, so I had to manually select my faces, but even after doing so, I noticed one region (see screenshot) where the two parts will touch because there is no offset. 

Am I doing something wrong, or can we not always rely on the Offset parameter and I have to think of another way to build these parts so they can be printed together and yet remain physically separated?



If anyone has the time and inclination to look at this document, please have a gander: https://cad.onshape.com/documents/a4fffc5d4661140d07d058cf/w/5e47121190aba3b18112f40c/e/5bd89b5b46314bcf9f668a4d

I'll keep trying to find a solution in the meantime. I don't know how document sharing works, so I'll save this as Version 2.0 and then keep working on Master.

Thanks in advance for any thoughts or advice!

tom_auger

I was able to resolve the issue in this instance by taking the offending face and using, well, Move Face. I was amazed that this worked as well as it did. Might be an alternative to using Boolean Offsets in some cases.

This is such an issue with 3D printing (not sure of other manufacturing methods) because of material tolerances and plastic expansion. I'm always taking my perfectly aligned parts and trimming away 0.5mm here and there to make them fit in reality.

tom_auger

I was able to resolve the issue in this instance by taking the offending face and using, well, Move Face. I was amazed that this worked as well as it did. Might be an alternative to using Boolean Offsets in some cases.

This is such an issue with 3D printing (not sure of other manufacturing methods) because of material tolerances and plastic expansion. I'm always taking my perfectly aligned parts and trimming away 0.5mm here and there to make them fit in reality.

michael3424

tom_auger said:

This is such an issue with 3D printing (not sure of other manufacturing methods) because of material tolerances and plastic expansion. 

Speaking for myself only, redesigning a subtraction manufactured (machined) part is only necessary when I somehow screw up the machining of the part and it gets redesigned to match what was made.  That's one of the benefits of being both the designer and fabricator.