[CHP] Aluminum on big cnc

My understanding is that the big CNC is not available to all the members. Right now it is reserved to the members that have funded the project. to the best of my knowledge, no one except this people is certify to operate this machine alone. But I might be wrong…

Anyway, you may want to share your settings for cutting this piece of aluminum. what is your feed rate, plunge rate and pass thickness?


It is not available to everyone yet due to safety reasons, just for people trained on it. I do know that includes Ryan, Coy, Ian and I believe Jon. (This is not an all inclusive list just who I can think of.) But I do not believe it has anything to do with who provided funding for this.
I believe I was told it can handle aluminum, but it was a passing comment and I do not want to be held to that alone.


Coy gave me basic training on the cnc, and I have cut MDF four or five times without breaking anything. The policy seems to be fuzzy to me but I assumed I’m ok to use it at least for plywood/mdf.

I will definitely share feed speeds etc when I get to my computer! Comments or criticism will be appreciated. I am using the zero-divide.net calculator.h


here’s the cutting parameters I would like to try:
end mill: 0.25 in diameter, 2 flute, HSS
pass depth: 0.1 in
spindle: 8000 RPMI
feed: 40 in/min
plunge rate: i have plunge rate set to 20in/min, but I am doing a spiral ramp-in, so the actual plunge rate is very slow


If you are doing a spiral ramp what is your spiral angle? What is your helix angle on the end mill?

The pass depth seems OK?

Do you have check that your torque x your speed is lower than the maximum power of the spindle?

What is your tool deflection?

Good luck!



Thanks for the reply Julien!
I made my first test cuts. I definitely should have calculated the torque x speed vs the spindle power, I stalled the spindle on my first cut. I then reduced the cut depth to a conservative 0.015in. This cut slow but turned out pretty nice. It could probably go deeper but I’ll keep it there for now to be safe.
I’m using vectric aspire…I’m not sure if there is an easy way to calculate the angle on the spiral cut. With the 0.015 cut depth it is a very shallow angle.

Usually, the spiral angle of the end mill is a data given by the manufacturer. The spiral angle for the ramp in could be calculated with proper tool: http://blog.cnccookbook.com/2012/03/07/helical-interpolation-ramp-angle-and-the-best-ways-to-enter-a-cut/

Or you can be conservative and take 5 deg. If your cut is a success, it is now what only matters.