Beginners Feeds and Speeds.

I am the beginner! This is a short post about what I have learned so far. I intend it only to show the method I use to decide how to set my speeds and feeds. Use at you own risk!

speeds and feeds 1

I begin with the chipload. It will be .05% to 5% of cutter diameter. Hard to soft materials. Some websites have chipload tables. If you find one with % chiploads, bookmark it.

Initially stick to three common spindle speeds, for ease of calculation…
7000- Foam PVC, other melty plastics, very low density materials.
18000- MDF, softwood, hardwood, acrylic, Delrin.
24000- Brass, aluminium, V engraving.

From this calculate feed rate.
(you are using mm cutter and revs per minute so the result is mm per minute)

Feed rate = Chipload x RPM x Number of cutting edges.

0.09mm(3% of 3mm cutter) x 7000(melty soft plastic) x 2 flutes = 1260 mm/minute

The other thing you need is pass depth.

  • With low density materials you can use diameter of cutter as a start and increase if everything is going well.
  • With medium density pass depth of cutter diameter or less
  • With hard it varies. 0.25mm is where I normally start.

Feed and speeds is a very complex subject with many variables. I would of course recommend reading up on some of the tool manufacturers websites to see what they say regarding the specific material you are cutting.

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