High Speed Machining

A brief overview of high speed strategies

Although high speed machining is mainly used on hard material the strategies that we use can be lent to a whole manner of common materials to significantly reduce cycle times significantly increasing manufacture productivity.

Utilisation of our high speed machines with large block look ahead and combining experience gained knowledge and techniques with the correct tooling enables us to effectively implement these strategies where ever possible.

The use of HSM strategies requires the material to be removed with very shallow cuts and with small step over. The smoothness of the machined surface is determined by the height of the scallop between adjacent passes . . . and by taking a smaller and smarter step over, the scallop height goes down. Lighter depth of cuts contribute to reduced hand polishing. At the same time, HSM offers an efficient way to use very small tools. This can make it practical for high-speed CNC machines to generate fine details that might otherwise require inserts or EDM.

  • Constant surface speed is critical to dimensional accuracy and surface finish.
  • Sharp direction changes cause a CNC to slow down as it decelerates and accelerates.
  • To keep the surface speed constant rounding moves are added to the tool path.

In addition to providing extremely high metal removal rates a key attribute of HSM over conventional machining is that in many cases the new process yields improved dimensional accuracy, as most of the heat generated is removed with the chips and hence does not build up in the work-piece to generate distortion.

Key points for HSM

  1. Tooling and specialist coatings to cope with increased chip heat (TiALN fails at 850°C)
  2. High speed spindles /ceramic bearings
  3. Heat shrink balanced tooling
  4. Knowledge of material harmonics/resonance
  5. Thermal growth compensation an spindle
  6. Chilled ball screws/bearings to combat thermal drift
  7. Large high pitch ball screws for rapid acceleration
  8. Rigid new machinery
  9. Large block look ahead on cnc control Cam package with hsm strategies and nurb options


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