2. All Machinists Know the Basics RPM = SFM * 4 / Cutter Diameter Feed Rate = RPM * Chip Load * Teeth Isn’t That Good Enough???
3. 4 Problems Tables Are Worst Case Estimates Chip Thinning Compensating for Odd Shapes Tool Rigidity Classic Formulas Don’t Consider All the Variables…
4. #1 Tables are Worst Case Estimates Only a Few Variables: Full Range of Tool Diameter, Depth of Cut, Width of Cut, Materials, etc. No Interpolation No Idea of Coolant or Other Conditions What About Micro-Milling? Is Manufacturer Pushing Tool Life or MRR? Have to Assume Worst Case HSM Toolpaths can go 3-5x Faster
5. #2 Chip Thinning Chip Thinning: Simple formulas assume the red chip The blue chip is reality. You have to feed faster to get to the recommended chipload!
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7. Rubbing = Heat = Poor Tool LifeShallow Cuts w/o Chip Thinning Adjustment Often Lead to Rubbing!
8. #3 Compensating for Odd Shapes Not all cutters are nice and square in profile Lead Angle Changes Feeds & Speeds Ballnose Changes Feeds & Speeds
9. #4 Tool Deflection All tools deflect, it’s about how much… Roughing: > 0.001” = Onset of Chatter Finishing: < 0.0002” for Accuracy and Finish What’s the Impact of HP on Tooling & Machine?
10. Optimizing Feeds and Speeds is About Mastering More Variables…Hard to do by hand!
11. So We Use a Calculator!Let’s See How With G-Wizard
12. For More Information Try the CNCCookbook Milling Feeds and Speeds Cookbook! www.cnccookbook.com
