Storm Trooper – Fifth Project, Lexan is Awesome

I friend of mine recently built himself a new computer. Spent weeks picking out parts and putting it together, and it turned out great. It’s mostly white, with black accents so he named the computer “Storm Trooper”. When he saw what the Nomad could do he asked if we would make him something he could put behind the side window of his case that had the computers name on it.

I had been wanting to try working with Lexan, so after putting together a design in Photoshop I loaded the image into MeshCAM. I don’t know how to use a CAD program, the Nomad is the kid’s machine and Dallas is learning CAD as part of a high school engineering class. So when I want to design something I use Photoshop to put together my designs and rely on MeshCAM to turn images into CAD designs.

By accident this is where I learned something that for me is rather important. I really like MeshCAM but as discussed previously the setting “Don’t Machine Top of Stock”, is being ignored by MeshCAM (don’t know if this is a bug or by design). I had resigned myself to just learn to deal with this limitation, but if you look at the toolpath above you will see that this time IT WORKED!.

I tried lots of different settings and found the trigger that caused this change. If the tool being used in the finishing path an Endmill (ie tool #102 or #112), MeshCAM will honor the “Don’t Machine Top of Stock” setting. But if the tool being used in the finishing path is a Ball (ie tool #101 or #111) MeshCAM will ignore the “Don’t Machine Top of Stock” setting. Can anyone explain why this would be?

Since I was working with a clear material, this made a big difference in the result. And what a result!


Another nice project. To save time machining, you can turn on Pencil finishing and then set the parallel finishing to only cut in X or Y, not X&Y. I also think you can change your parallel stepover to be .05 or more with Pencil finishing on.

Regarding the Top of Stock, with the profile of a ball mill, the cutter will follow an arc to the top of the stock. This leads to ragged little edges along the top, depending on the cutter, machine, and material, but it’s “mathematically correct” For a part like the one you’ve shown, a flat cutter is the way to go anyway.



Thanks for sharing your projects. I appreciate the effort and the things you are doing are interesting.
A professor once told me to study those that have gone before and have a goal of only making new