CBN Insert Cutting Speed, Feed and Depth of Cut
Use these recommended starting ranges for CBN and PCBN turning, finishing and milling. Final parameters must be adjusted to the insert grade, geometry, workpiece hardness, cutting continuity, machine rigidity and required surface finish.
Treat the Values as Starting Ranges
Begin conservatively, inspect the cutting edge and surface, then optimize one variable at a time.
CBN Cutting Parameters for Hardened Steel
Use lower speed ranges as interruption increases, and lighter feed and depth of cut for final turning.
| Operation | Condition | Vc (m/min) | ap (mm) | f (mm/rev) | fz (mm/tooth) |
|---|---|---|---|---|---|
| Turning / Roughing | Continuous | 80–160 | 1.0–2.5 | 0.1–0.5 | — |
| Turning / Roughing | Interrupted | 80–125 | 1.0–2.5 | 0.1–0.5 | — |
| Final Turning | Continuous | 125–210 | 0.1–0.5 | 0.05–0.2 | — |
| Final Turning | Interrupted | 100–150 | 0.1–0.5 | 0.05–0.2 | — |
| Milling | Starting range | 80–200 | 0.1–2.0 | — | 0.1–0.25 |
Confirm the PCBN grade and edge preparation before using the upper speed range.
CBN Cutting Parameters for Cast Iron
Grey cast iron can use significantly higher cutting speeds than chilled cast iron.
| Material | Operation | Vc (m/min) | ap (mm) | f (mm/rev) | fz (mm/tooth) |
|---|---|---|---|---|---|
| Chilled Cast Iron | Turning / roughing | 60–140 | 1.0–2.5 | 0.2–0.6 | — |
| Chilled Cast Iron | Final turning | 70–160 | 0.1–1.0 | 0.1–0.35 | — |
| Chilled Cast Iron | Milling | 100–200 | 0.1–2.5 | — | 0.1–0.25 |
| Grey Cast Iron GGG 20–30 | Turning / roughing | 500–1500 | 1.5–4.0 | 0.2–0.6 | — |
| Grey Cast Iron GGG 20–30 | Final turning | 800–2000 | 0.5–1.5 | 0.1–0.35 | — |
| Grey Cast Iron GGG 20–30 | Milling | 800–2000 | 0.5–4.0 | — | 0.1–0.35 |
| Grey Cast Iron GGG 40–70 | Turning / roughing | 500–1200 | 1.2–3.5 | 0.2–0.5 | — |
| Grey Cast Iron GGG 40–70 | Final turning | 800–2000 | 0.3–1.3 | 0.2–0.3 | — |
| Grey Cast Iron GGG 40–70 | Milling | 800–2000 | 0.5–3.5 | — | 0.1–0.3 |
Verify the exact cast iron grade, hardness, inclusions, scale and interruption before selecting the upper range.
Starting Parameters for Other Workpiece Materials
These applications require additional confirmation of the PCBN grade and machining condition.
| Material | Operation | Vc (m/min) | ap (mm) | f (mm/rev) | fz (mm/tooth) |
|---|---|---|---|---|---|
| Heat-Resistant Alloys | Turning / roughing | 100–200 | 1.5–2.5 | 0.15–0.35 | — |
| Heat-Resistant Alloys | Final turning | 120–250 | 0.1–1.5 | 0.1–0.25 | — |
| Heat-Resistant Alloys | Milling | 150–300 | 0.1–2.5 | — | 0.1–0.35 |
| High-Alloyed Steels | Turning / roughing | 60–110 | 0.5–2.0 | 0.15–0.3 | — |
| High-Alloyed Steels | Final turning | 80–150 | 0.1–0.5 | 0.05–0.2 | — |
| Sintered Metals | Turning / roughing | 180–320 | 1.0–2.5 | 0.2–0.35 | — |
| Sintered Metals | Final turning | 200–380 | 0.1–1.0 | 0.1–0.3 | — |
| Sintered Metals | Milling | 150-300 | 0.1–2.5 | — | 0.1–0.35 |
The sintered-metal milling speed in the supplied image is inconsistent and should be checked against the original document before publication.
How to Adjust Speed, Feed and Depth of Cut
Start from the lower half of the range when the setup is new or the cut is interrupted.
Cutting Speed Vc
Reduce speed if flank wear, thermal damage or edge instability develops too quickly.
Feed f
Feed affects chip thickness, cutting load and theoretical surface finish.
Depth of Cut ap
Confirm that the PCBN edge length and insert structure support the selected engagement.
Interrupted Cutting
Use lower speed direction and a tougher grade as impact and chipping risk increase.
Machine Rigidity
Reduce cutting load where holder overhang, clamping or component support is limited.
Surface Finish
Optimize feed, nose radius, vibration control and tool wear together.
Information Needed to Confirm Cutting Parameters
Match the starting range to the actual grade, insert code, hardness, operation and current failure mode.
CBN Cutting Parameters: Common Questions
Are these CBN cutting speeds guaranteed values?
No. They are recommended starting ranges. Final values depend on the PCBN grade, insert geometry, workpiece hardness, machine rigidity, interruption and required surface finish.
Should interrupted cutting use a lower speed?
Usually yes. Interrupted cutting increases impact and chipping risk, so a lower speed direction, tougher grade and stable edge preparation may be required.
Why is grey cast iron cutting speed much higher than chilled cast iron?
Grey cast iron and chilled cast iron have very different structures and hardness. Chilled or hard zones are more severe on the cutting edge and normally require lower speed.
Can the same cutting data be used for every PCBN grade?
No. Different grades balance wear resistance and toughness differently. Confirm the range for the selected grade and insert code.
What should I provide for a cutting-parameter recommendation?
Send the material, hardness, operation, insert code, grade, cutting continuity, current speed, feed, depth of cut, tool life and failure mode.
Send Your CBN Machining Application
Share the material, operation, insert code and current process. Our team will review the starting speed, feed, depth of cut and PCBN grade.
- Workpiece material and hardness
- Turning, finishing, boring or milling operation
- Insert code, grade and tip structure
- Continuous or interrupted cutting condition
- Current speed, feed and depth of cut
- Tool life, failure mode and target result
