# Actual Chip Thickness Calculation for CNC Machine Endmills

Have a look at this image:

this image is from: https://www.guhring.com/Tech/endmillcalc

I would like to know how the formula for the "Actual Chip Thickness" is done In this case, it is 0.104

Using speeds and feeds for this tool: https://www.guhring.com/ProductsServices/SizeDetails?EDP=9067370160000 (Using HPC-ROUGHING; Aluminium, Al-wrought alloys, Al-alloys)

I managed to replicate all the other formulas in my spreadsheet it's just this one I'm having an issue with. I would like to have this because it seems to affect the (actual) MRR

I have contacted the manufacturer and a CNC form with no luck so far Maybe I should ask this in the Mathematics community if no one here knows?

• The chip thickness is based on the depth of cut ie the rate the cutting edge is advanced into the material that is the pitch oif you think about a thread. 1 turn = 1mm etc Mar 31 at 12:09
• The "radial chip thinning" calculation recommends 0.16 FZ, the manufacturer recommends 0.13 Fz, but with a stepover of 3.2, the actual Fz is 0.104 (thats why the radial chip thinning says 0.16 so you can get your 0.13 for 3.2 ae). I want to know how they calculate the 0.104 to get the 'actual' MRR (for comparison reasons). Mar 31 at 17:35