How the chip is formed
In climb milling, contact starts with a thicker chip and ends near zero thickness. Conventional milling starts with a very thin layer before the edge develops a full chip.
Key differences
| Feature | Climb | Conventional |
|---|---|---|
| Chip at entry | thick → thin | thin → thick |
| Typical force tendency | pushes the part toward the table | can lift the part |
| Rubbing at entry | usually lower | usually higher |
| Machine requirement | low backlash and rigid drive | more tolerant of an older feed mechanism |
When to choose each direction
On a modern rigid CNC with carbide tooling, climb milling is normally preferred. Conventional milling may be justified where feed-drive backlash exists, when entering a hard surface layer or in an operation specifically defined by the tool maker.
With weak workholding, the real force direction and support may matter more than a general rule.
Direction in CAM and at the machine
Verify a CAM climb/conventional option together with spindle direction, contour side and cutter compensation. In pockets and complex paths, local engagement changes continuously, so inspect contact animation rather than relying on one path arrow.