Cutting styrofoam, a work in progress

I put my lowrider3 on steroids to be able to cut 100mm styrofoam. I was not able to find a 100mm router bit for a price that doesn’t cost me a kidney yet, so now working with 75mm. Made a spoilboard of styrofoam today and tried flattening it. As you can see the router needs some tramming and the dust collection is still sub-optimal. Need a larger diameter hose, its now 42 mm, want 65 or something like that. For now its working allright to cut some styrofoam to build a dragons head. I wanted to carve it from an stl, but it costs too much time, mainly because of the large (and slow) z-travelling. Now I’m going to cut out the outline of each layer and do the rest of the carving by hand.


I have some ideas to throw out about your Z movement. I assume you are cutting the foam in layers and assembling the result.

I’m not sure what tools you are using to author your g-code, but in Fusion 360, there is a 3D contour toolpath. This toolpath will have little Z movement and just make multiple passes around the outside of your object. The level of detail achieved will be defined by the Maximum Step Down. You will still have significant hand work, but having more detail to guide the shaping will make the carving go much faster. I’ve never used it, but Fusion 360 also has a Ramp toolpath which might be even better for layers.

The Z axis federate is limited in the firmware, and you can increase the maximum federate using a M203 g-code. Note that this g-code uses millimeters per second, not millimeters per minute. At some point, the federate will be too fast for the hardware, and you will lose steps. That point is based on multiple factors and is best found by experimentation.

Higher voltage for the steppers will increase torque at higher stepper motor speeds. If you are running at 12V, changing to 24V can be helpful.

If by chance you are using 1-start or 2-start lead screws, replacing them with 4-start lead screws would be beneficial. Note that 4-start is the common one and the one assumed by the firmware.

Not related to the Z movement, but, in my layered works, I’ve been well served by authoring in two reference holes. I then thread the layers on dowels assuring that everything is rotated and aligned correctly.

I’d love to see your foam creations posted on the forum!

1 Like

Yes, that’s right, just like its predecessor

I use Estlcam for cam and for controlling the lr3.

I will look into cam in fusion later, but i haven’t got enough spare time right now. Too much scenery to build for our musical Shrek and too few people to help…

Thank you for your extensive answer!

I did the outlines and one of the other “set builders” did the carving with a hotknife

I 3-d printed the eyelids, they are not built in yet. I tried to print the eyes, but my 3d printer’s extruder broke down (again). Still can’t aford the mk4, but bought a hemera extruder as a replacement. One day I want to build a V4… thats where the hemera is going to go


Me with my co-builders.