Machining Time Estimation
Every optimization result is quoted as a time — 303 minutes down to 95 — so it matters what that number is and is not. HiNC's machining time is computed from the ideal feed rate in the NC or CL program together with the maximum rotary-axis speed limits. It does not model dynamic behaviour: no acceleration and deceleration ramps, no look-ahead, no servo lag.
Why It Matches Controller Simulators
That simplification is the same one the controller vendors' own simulators make, which is why the two agree closely. On a five-axis impeller program:
| Estimator | Cutting time |
|---|---|
| Heidenhain simulator | 15 h 02 min |
| HiNC | 15 h 05 min |
| Difference | 0.39% |
Agreeing with the vendor's simulator is a useful check that the program was read correctly. It is not evidence that either number matches the shop floor.
Why the Shop Floor Differs
Real machining time can differ substantially from any of these estimates — the vendor's included — because the dynamics they all omit are real. Acceleration limits at direction changes, look-ahead window size, and block processing rate all cost time that no ideal-feed estimate contains. The same NC on two controllers with different look-ahead settings takes different times.
The consequence for reading an optimization result: trust the ratio, not the absolute. Before and after are computed the same way and omit the same dynamics, so a reported reduction from 303 to 95 minutes is a sound statement about what the optimization achieved, even where neither number will be observed on the machine.
Feed rate acceleration is also the reason an optimized corner feed is conservative rather than wrong — see Optimized Feed Rate at Corners.
See Also
- Optimized Feed Rate at Corners — the same missing dynamics, seen from the corner where they matter most
- NC Optimization Principles — what the optimizer changes to produce the reduction this page quantifies
- Optimization Results — the tables whose ratios this page says to trust