.125 styrene feeds/speeds

Hi everybody!

I’ve got a 1000x1000 x carve that I’m working with at a maker space and I’m working on cutting out some parts out of .125" styrene with a .125" two flute upcut bit. The router is the standard issue dewalt and I’ve got x carve pro to generate the g code. The hard part is I have no ide where to start to figure out my feeds and speeds. I tried g code wizard but that seems to be a bit too advanced for me.

Suggestions on starting out settings?


You can use this formula to calculate feeds and speeds…
FeedRate= ChipLoad x ToolDiameter x #Flutes x RPM

I have a lookup table that specifies a chipload of 0.003" for plastic using a 0.125" diameter tool.
FR = 0.003" CL x 0.125 ToolDia x 2 flutes x 16000rpm
FR = 12inches/min (305mm/min)

This is where “I” would start to do some practice cuts. You may have to make adjustments based on your results. I have been looking for a styrene project myself.

Thanks. That’s the formula I need

I did some reading and others that are making the same parts as me suggested a slower feed rate so the plastic doesn’t gum up the tool.

I’m making R2D2 parts. By the way.

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I would switch to a downcut tool also

Dave evert plans?

better! These plans are so much easier to construct.


I need to double check. I might be using a downcut. It’s been a while since I was working on R2 but now I have time to get back into it.

Are you on astromech?

I am. I have a build thread that I’ve been neglecting. I think my username there is “TheDon”


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Slightly jealous of you David

Also the styrene seems to cut nicely with m 1/8" bit. At 30 IPM /24k RPM’s with a plunge of 15 IPM. Makes a lot of tiny chips. I really need to make the line loc dust collection work.

Mines the green R9, that’s sennas place.

Glad to find other R2 guys talking about this. I was working on an R2 build with students on our X-Carve at school and ran into lots of trouble trying to cut the media-conversions files. Our bits would collect material, then melt plastic on the next pass when the material came in contact with the surface of the styrene sheet. What a mess.

We had a difficult time getting the pdf drawings into Easel, too. Ended up using VCarve to export gcode and get some done, but then contended with the melting.

I’m planning another R2 build of my own now and I’m thinking I’m going to attempt styrene again. Been reading through the forum to see what’s happened in X-Carve since. I really wish they’d make Easel (or even Pro now) capable of working with pdfs. It would save us so many headaches.

To address the melting, I’ve found another builder who uses an X-Carve with a Makita router (with a lower, 10krpm speed minimum) and a straight cut bit to produce good results. I’m thinking about using the supplied DeWalt (to save hassle with the mount) and rigging in a SuperPID.


I think I’m going to get the super pid. There are a few other r2 builders I was talking to and they swear by it so I just might have to give it a try.

@JohnDWilliams. I cut foam without melting. Here is a quick video


Great video Phillip, thank you for sharing.

Plastic/foam melting when carving => go faster and/or lower RPM.

Awesome video, and a super cool project!

I should have clarified - in this project, I’m working with High Impact Polystyrene.

I’ll bet some of it might translate though.

I have a question about cutting Styrene with my cnc machine im using lazy cam with dxf converting to gcode and for some reason I can ever get the cnc to cut curves i have jagged edges. Is there some thing i am missing it should be able to cut clean curved lines on 39/64 Styrene Plastic. Any thoughts.