The Physics of HSM
Traditional milling takes heavy cuts at slow speeds. High Speed Machining (HSM) takes light radial cuts at very high speeds and high feed rates.
The goal is to reduce the Tool Engagement Angle.
1. Chip Thinning
When taking a light radial cut (less than 50% of cutter diameter), the actual chip thickness is thinner than the programmed feed rate.
2. Heat Management
In HSM, the heat goes into the chip, not the tool or the part. Because the contact time is so short and the chip is ejected so fast, the tool stays cool.
Core Strategies
1. Trochoidal Milling
A circular motion used to machine slots wider than the cutter. The cutter spirals into the material, maintaining a constant low radial load. Allows cutting full depth (2xD or 3xD) in a single pass.
2. Peel Milling
"Peeling" thin layers off the material at high feed rates. Used for facing or profiling. The stepover is typically 5-10% of cutter diameter.
3. Plunge Milling
Converting lateral force into axial force. The tool cuts along the Z-axis (like a drill). Ideal for deep pockets or weak setups where vibration is an issue.
Parameter Guidelines
| Strategy | Radial Depth (Ae) | Axial Depth (Ap) | Speed Adjustment |
|---|---|---|---|
| Dynamic Roughing | 5% - 15% Dia | 200% - 300% Dia | +20% SFM |
| High Feed Milling | 40% - 60% Dia | 2% - 5% Dia | +50% Feed |
| Trochoidal Slotting | 10% - 20% Step | 200% Dia | +30% SFM |