Milling and grinding are both machining processes used to remove material from a workpiece, but they differ in their cutting action, tool geometry, and resulting surface finish.
Milling
Milling uses a multi-toothed cutter rotating at high speeds to remove material from the workpiece. The cutter has a specific shape and size, which determines the final shape of the workpiece.
- Cutting Action: Milling involves a chip removal process where the cutter teeth engage the workpiece and remove material in the form of chips.
- Tool Geometry: Milling cutters can have various shapes and sizes, including end mills, face mills, and slot mills.
- Surface Finish: Milling typically produces a rougher surface finish compared to grinding.
Grinding
Grinding utilizes a rotating abrasive wheel to remove material from the workpiece. The abrasive wheel consists of abrasive particles embedded in a bonding material.
- Cutting Action: Grinding involves abrasive wear where the abrasive particles on the wheel remove material from the workpiece by scratching and tearing it.
- Tool Geometry: Grinding wheels come in various sizes, shapes, and abrasive materials, depending on the application.
- Surface Finish: Grinding produces a very smooth and precise surface finish due to the fine abrasive particles.
Key Differences:
| Feature | Milling | Grinding |
|---|---|---|
| Cutting Action | Chip removal | Abrasive wear |
| Tool Geometry | Multi-toothed cutter | Rotating abrasive wheel |
| Surface Finish | Rougher | Very smooth |
| Material Removal Rate | Higher | Lower |
| Applications | Shaping, contouring, and cutting slots | Fine finishing, sharpening, and deburring |
Examples:
- Milling: Creating a groove in a metal block, machining a complex gear shape.
- Grinding: Sharpening a knife blade, smoothing a metal surface to a high polish.
Practical Insights:
- Milling is often used as a primary machining process to shape the workpiece, while grinding is used as a secondary process to refine the surface finish.
- The choice between milling and grinding depends on the required surface finish, material removal rate, and desired shape.
