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A quick feeds and speeds course
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A quick feeds and speeds course


This slideshow is a quick course in speeds and feeds for cnc machinists

This slideshow is a quick course in speeds and feeds for cnc machinists

Published in Technology , Business
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  • 1. G-Wizard Machinist’s Calculator
    A Quick Feeds and Speeds Course
  • 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!
  • 6. Irony: Babying the Cut is Bad For Cutter Life!
    Think of the Cutter Edge Radius Versus the Chip Thickness:
    Radius <= Chip Thickness: Shearing Cut
    Radius > Chip Thickness: Rubbing!
    • Chip pushed under not over
    • 7. Rubbing = Heat = Poor Tool Life
    Shallow 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!