Best advice for efficiently machining a two-piece mold for miniature skateboards (?)

[traditional.builds]

Hey so this is a bit random but I started making miniature skateboards for fun and wanted to take it in a new direction with an actual mold to press layers of veneer.

I downloaded an STL file of a skateboard mold and resized it to fit my dimension (roughly 100mm x 37mm, and oversized a bit for wiggle room). 

My main issue is that the STL file is made up of hundreds of triangles and it is very demanding on my desktop. Especially when I start to apply toolpaths to the mold, it sometimes takes a minute or two to render the toolpath and is very laggy. I understand this may be a computer issue, but what i am asking is if there is a way to "simplify" the STL file. I converted the STl file into a solid body but this did not fix the issue. It allows me to slightly edit the model and apply tooling, but it is still a very demanding file.

Is there an easier way to do this? This is my first 3D mold I have ever made by CNC machine and right now I just want to finalize this one before moving on, although in the future I would love to be able to slightly modify the mold's shape, such as changing the contour, the width, length, and depth to make different skateboard shapes. As of now, I don't see myself being able to do this with the current setup I have.

Any thought or ideas on how I could simplify this process? I can attach the file as well as a screenshot of the file I am working on. This will be super duper helpful if anyone has some advice for me.

*There are also a couple, seemingly random, "rapid collision with stock" errors for almost no reason. I know there is a reason, but when I watch the simulation it literally makes no sense as to what the "collision" is and why it's happening.

Thanks a ton in advance,

Mike

[oscar-cadcampilot · Accepted solution]

From your image it looks the issue with your converted solid file from stl is that you didn't processes it correctly. There some good tips on the process workflow on the Fusion 360 Self-Paced Learning webpage here.

In short, you'll need to make sure the original mesh (stl) is clean and create face groups to convert into a parametric solid, if possible.

As for the stock collision in you toolpaths, those may be showing if you don't have a rough toolpath that removes enough material before a semi-finish or finish toolpath, or a drilling toolpath where there would be material above the start point.

I've also seen this when there's zero thickness between a wall and the shank of your tool on a contour pass in a milling toolpath.

[engineguy · Accepted solution]

@traditional.builds 

For what it`s worth there are dozens of Skateboard Mold file available for download, so download only files with types that are easily edited, examples are :-  .stp, .iges, .sldprt

The above examples are "ready to rock" and will be much more manageable for your computer 🙂

Go back and look at where you got your file from and see if there is an option to download in a different format, most CAD stuff usually can be downloaded in different formats.

Fusion is not the best for working with .stl file yet so best to stay away if you can.

Meantime here is a mold design that I found on Grabcad in about 2 minutes which had the option to download as a .sldprt (Solidworks) file, loaded straight in to Fusion and when saved out as a Fusion .f3d file is only about 80Kb file size, super quick to work with 🙂

Save you hours if not days of headaches 🙂 🙂

[traditional.builds]

You are awesome! Thanks for the reply it was super helpful. I will look into some premade molds and try working with those and eventually I will figure out the best methods to modify them as needed. Thank you for attaching a mold, I will take a look and test some things out. 

Very helpful, thank you!

Mike

[traditional.builds]

Thank you so much for the detailed response. I will be taking a look at the link you directed me to and play around with some pre existing molds. I definitely need some more practice with machining 3D shapes on the CNC. I have made a few 3D pieces but they are all very simple. The skateboard mold has been giving me issues but this helps me out a ton so thank you!

Mike