DISCUSSION: Multicam CNC Optimization for Cuts & Updating the Tool Database

This discussion is about finding the optimal (in terms of speed vs quality vs tool life) and hopefully accumulating some data for DMS and the tool database.

Anyone can chime in, but I suppose this is more geared for users who have more experience with the Multicam and have sufficient time on it.

I’ve discussed with a few of the other CNC gear heads on here for over a year now about this topic and like many of you may know it’s all about trial and error. With more people adding to the discussion I figure it’d be faster to get some good quality data and maybe start getting some of this plugged into the tool database so users can save time, get better quality finishes, and save the space from either not having bits on hand, dull bits on hand, and saving money.

I cut mostly plywood (maple ply and BB) on the CNC but will do hardwood projects from time to time so most of my thoughts will revolve around that.

Standard chip load/feedrate/RPM calculators are a great starting point, but really are just that. I’d like to see if any of you have real experiences on finding optimal settings and what bits you are using.

I’ve played around a lot with 1/4" compression, 1/4" down cut, but would like to try 3/8" compression and 3/8" down cut to see if single pass 3/4" Ply can be sped up.

There’s also limited material regarding HP/kw (we have 4hp) to torque information that I can find (resulting in tool deflection) that I can find. GWizard is useful but Brian Davis has said before that it’s ultraconservative. So if anyone can chime in on that, it’d be appreciated. How does this correlate to running a 3/8" or 1/2" bit in mathematical terms and in turn what can we assume would be safe upper values of running these bits at a full pass.

Format: Bit (short description + # of flutes) / Depth of Cut (DOC) / Material / RPM / Feed rate
Ex: 1/4" 2+2 Compression / .75 (Plywood) / 23500 RPM / 282 IPM

For the new comers and those that want to try and optimize their stats the calculation for finding out my IPM is:
Feed Rate = 23500 (RPM) x 2 (# of flutes) x .012 (Optimal chip load for bit to material) x .5 (factor for 3x DOC)

The reason the stock value in Vcarve isn’t optimal is given the optimal chipload:
Feed Rate = 18000 x 2 x .012 x .5 = 216 assuming a .75 DOC. The value in the database is 252 IPM . This is the obnoxious screaming we hear sometimes. I believe with the default value of a standard .25 DOC the calculations should be 18000 x 2 x .012 = 432 or ~42% faster!

Settings for the Multicam (correct me if I’m wrong) in helping you try to optimize 4HP, 25000 max RPM, 650 max IPM.

I’ll post some other settings later when I get time this afternoon

1 Like