Workpiece material / Plastic
Acetal (Delrin) speeds and feeds
Starting surface speeds and chip loads for milling Acetal (Delrin). Every value below is cross-checked against published sources and linked, so you can re-verify it yourself. Starting points, not limits.
| Value | Used | Provider readings (each linked) |
|---|---|---|
| Surface speed, HSS (estimated) | 400 SFM | |
| Surface speed, carbide (estimated) | 1,000 SFM | |
| Chip load @ 0.25" (estimated) | 0.0025 in/tooth |
| 0.125" | 0.25" | 0.5" |
|---|---|---|
| 0.0010 | 0.0025 | 0.0050 |
| Constant | Value | Readings |
|---|---|---|
| Kc1.1 (specific cutting force) (estimated) | 250 N/mm2 | ISO group-typical - see notes |
| mc (chip-thickness exponent) | 0.20 | ISO group-typical - see notes |
| Unit power (estimated) | 0.10 HP/(in3/min) | ISO group-typical - see notes |
The power-model constants (Kc1.1, mc, unit power) are class-typical values for the ISO material group, used only for a rough spindle-power estimate. Only their relative ordering and internal consistency are verified, never tuned to match any vendor.
Notes
Acetal (Delrin) machines cleanly at high speed with sharp tools and a generous chip load; the limit is usually melting from rubbing, not cutting force, so keep speeds high and the edge sharp. Power constants reflect the low cutting force of plastics. The surface speeds are plastics-machining starting estimates (flagged), not read from the general overview cited.
Verify this yourself
Every number above links to the provider that publishes it. Open two or more and confirm they agree with what is shown here. Full source list:
Take these into the feeds and speeds calculator for RPM, feed and power. Start a little under these numbers on a light or flexible setup.