Making a highly detailed aluminum mold

Hi all,

I’m trying to get a aluminum mold quoted but the file is a mesh that I cannot export to step file. I basically created a map displacement from an image to create the details but the only way I have found to save the file properly is through a stl format.

The aluminum mold suppliers I have talked to require a step format. I need some help because I’m inexperienced with this issue. Help!

The programs I have access to are Rhino 5 and Solidworks.

Side note: Is this the best way to get a highly detailed, precise aluminum mold made?

A STL file is a polygon mesh format. It is made up of many tiny triangles and is acceptable for 3D printing, but not for CNC machining or other precise methods of production.

If you are trying to create tooling, you need access to a true CAD tool. Rhino and Solidworks can both create the surfaces needed - I am not sure what you used to generate your displacement map but displacement mapping is a technique used for rendering and animation, not production.

If it’s a very elaborate pattern you would need to figure out how to rebuild the design in Rhino or Solidworks (as surfaces/solids).

The only other alternate I could suggest is there are tools out there which will convert mesh files into NURBS models, but it is still a very labor intensive process and may or may not be feasible depending on your design.

You would need to find a moldmaker who can actually machine the displaced mesh(CAM software that can do it certainly exists, ) somehow recreate it as actual surfaces (very tricky,) or get a mold cast using an rp’d master pattern.

There are ways to do this with your existing tools, or with other options.

  1. Depending on the density/size of your mesh, you can use Rhino’s MeshToNurb command. This will quite simply create one NURBS patch for every one polygon. This results in super heavy data, but can work if your vendor can handle it or if your file isn’t particularly large.

  2. Try the technique outlined in this tutorial. SOLIDWORKS Forums
    Basically it involves saving your mesh file as a DXF, which Solidworks can import and then convert to NURBS. It does this in much the same way as Rhino’s MeshToNurb.

  3. Find a molder who can deal with mesh data (they exist)

  4. If you’re going to do this kind of thing often, just buy Power Surfacing. I hardly use it for its primary purpose (native sub-D modeling in SW) but use it all the time for its other purpose: mesh-to-surface conversion. It does the translation automatically.

Thanks for all the info. All that helps me out a lot.

  1. How would a molder produce the part? Would they 3d print the data and make a mold based off of that? I would need precise details vs. free handing. I have made products that required molds but the mold developments weren’t part of my work day.

  2. I have never used a 3d scanner. What type of data do they typically produce? and would one be able to CNC that data?

I want to be able to test the part with a 3d print (that’s not an issue) and then make the mold with the negative data. I’m trying to cut down my development times and that is why I’m tying to go straight to a CNC’d mold, without using a molder.

The issue is the very tight detail that our current hand made molds have is tough to model without exporting the map displacement or 3d scanning. Fun stuff!

If you have artwork for the texture, Mold-Tech can produce the texture and apply it to the mold like any of their other textures. You may want to cut a steel tool if you are going to texture it.