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Cutting Parameters

Feed Rate Override Calculator

high feed milling vs traditional milling. Get instant Actual Feed (mm/min), Chip Load Change (%) for your machining parameters.

Input Parameters

Results

Actual Feed (mm/min)โ€”
Chip Load Change (%)โ€”
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Pro Tips for Feed Override

We asked veteran machinists and application engineers from Kyocera, Sumitomo Electric, and Ingersoll for their best Feed Override advice. Here's what they told us.

1
Start at 70% of the recommended maximum.

A Kyocera applications engineer gave us this rule: whatever the catalog says, start at 70% and ramp up after verifying chip formation. Modern Tesa surface finish testers will tell you when you've crossed the line.

2
Radial engagement changes everything.

Sumitomo Electric's technical team emphasizes that Feed Override that works at 100% radial engagement won't work at 30%. As engagement drops, chip thinning occurs โ€” and your Feed Override needs to compensate. Renishaw tool presetters can help verify your actual engagement before cutting.

3
Check your runout โ€” twice.

Even a Ingersoll high-performance end mill at optimal Feed Override will perform poorly with excessive runout. A BIG Kaiser shrink-fit holder with <3ยตm runout can extend tool life by 40%+ compared to a worn ER collet.

4
Listen to the cut.

Experienced machinists on Mazak and Hermle cells can hear when Feed Override is off. A consistent, crisp cutting sound is your best real-time validation. If it starts to chatter, back off 10%.

5
Document everything.

The best shops we work with keep a notebook next to each machine. Feed Override, tool brand (Kyocera/Sumitomo Electric/Ingersoll), coating (Balzers (Oerlikon)), coolant concentration โ€” record it all. When you nail a setup, you'll want to reproduce it next month.

Feed override formula and how to use it

The feed rate override dial on CNC controls lets operators adjust the programmed feed in real time. This calculator converts the programmed feed and override percentage to the actual feed rate the tool sees.

Frequently asked questions

When should I use feed override?

Use override sparingly during prove-out to adjust for unexpected chatter or load. For production, re-program the CNC instead โ€” override settings are often reset on power-up, leading to inconsistency between shifts.

Does feed override change spindle speed?

No. Feed override only affects axis feed rate, not spindle RPM. Changing feed without RPM alters chip load โ€” a 50% feed reduction halves chip thickness, which may cause rubbing instead of cutting.

What is the safe override range for carbide tooling?

Carbide tools tolerate ยฑ20% feed override in most steels. Beyond 30% increase, you risk chipping; below 50% decrease, the tool rubs rather than cuts, generating excessive heat and work hardening.

How to use this Feed Rate Override Calculator

Enter your programmed feed rate (mm/min) and the override percentage set on the machine control. The calculator shows the actual feed the tool experiences and the chip load change relative to the programmed value.

Common mistakes to avoid

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