Making a compression mould from a complicated non-symmetrical part.

[joshua_tuffnell]

Hi all,

This is my first time using this forum so please let me know if I have missed any useful info. I have an STL file from a (relatively) complicated part. I'm trying to make a 2 part compression mould i.e. a positive and a negative rather than just two halves. I was following along a useful video - https://www.youtube.com/watch?v=nNP4aMrQnjU but there is a step around 1:45 where they select the outline of the part, but I cannot find an easy way of doing this.

I have attached a .f3d file although I am not sure what is the easiest way to share the part.

Any advice would be appreciated,
Josh

[TheCADWhisperer]

@joshua_tuffnell 

If this were my work -

the first thing I would do is remodel proper geometry using the stl only as reference.

If you closely examine the imported stl geometry you should observe that there are no curves. Not one!

All straight lines and faceted planar triangle that shaded sort of look like curves until examined closely.

Can you get a better quality native file from the source (stl will always be rubbish).

[joshua_tuffnell]

@TheCADWhisperer Thanks for the quick response. I understand that remodelling everything in fusion 360 would be ideal but the purpose of this project was to use exported X-ray CT data (in STL format), tidy up the mesh a bit in fusion 360 and then create the 2 part compression mold.

Remodelling isn't desirable for this purpose because: the stl file with its polygons is good enough quality, the time it would take me to remodel it wouldn't be efficient and the process could then be applied to more complicated parts.

[davebYYPCU]

(Never thought I would say this )

Mesh > Tesselate
Converts the mould parts to STL format, and the combine operations will work.

Bodies for the operation must all be the same type.

That movie was painful, didn’t get to the end.

Hole for bolts - draws a circle, sheesh.

Might help…..

[TheCADWhisperer]

@davebYYPCU 

Going to have a really tough time getting a parting line with this faceted geometry.

[joshua_tuffnell]

@TheCADWhispererYes, this was one of the main issues I was having. I have tried creating face groups but the edge is not well defined. It also rules out using the loft tool.

[TheCADWhisperer]

@joshua_tuffnell 

If you Surface Swept an angled line around the profile and then use the Surface to trim to a clean edge - then I think it would work.

None of this is beginner level endeavor.

You also need to clean up the edges of the holes.