Carbide Insert Cutting Data: Speed, Feed and Depth of Cut | JetCutt

How to Set Cutting Speed, Feed and Depth of Cut for Carbide Inserts

Carbide inserts give a machining process a wide operating window, but the best result rarely comes from copying one number into every job. Cutting speed, feed and depth of cut must be matched to the workpiece, insert grade, cutting geometry, machine rigidity, coolant strategy and the actual engagement. This guide provides a practical method for setting the first trial and then improving it with evidence from chips, surface finish and tool wear.

Quick answer: Start with the insert manufacturer’s recommended cutting-data range, select speed from the workpiece and grade, set feed from the nose radius or milling geometry, and choose a depth of cut that keeps the edge engaged safely. Run a controlled first piece, change one variable at a time, and record wear and part quality before increasing output.

The three cutting parameters at a glance

Parameter	Typical symbol	What it controls	What to watch
Cutting speed	v_c (m/min)	Heat generation and productivity	Crater wear, flank wear, built-up edge and thermal cracks
Feed	f_n (mm/rev) in turning; f_z (mm/tooth) in milling	Chip thickness, cycle time and surface finish	Edge chipping, vibration, burrs and feed marks
Depth of cut	a_p in turning; a_e/a_p in milling	Material removal per pass and cutting-force level	Deflection, chatter, notch wear and insert stability

1. Start with the correct data family

Use the data range intended for the exact insert grade, chipbreaker or geometry, workpiece group and operation. Turning and milling values are not interchangeable, and a finishing geometry should not be loaded with the same feed as a roughing geometry. Manufacturer calculators and tooling guides are useful starting points because they connect material, tool style and machine conditions before the first cut.

For a new application, record the insert designation, nose radius, coating, workpiece hardness, stock condition, coolant method and machine power. This small record prevents a common mistake: comparing a result from a sharp finishing edge with data intended for a tougher roughing edge.

2. Choose cutting speed by heat and workpiece behavior

Cutting speed is the first lever for managing heat. Tough steels, nickel alloys and work-hardening stainless steels often need a conservative starting point, while free-cutting steels and stable cast irons may allow a wider speed window. The insert grade also matters: a wear-resistant grade may support higher speed in a stable cut, while a tougher substrate may be the safer choice when interruption or impact is present.

Do not raise speed simply because the chip looks small. Check the workpiece surface, the cutting edge and the temperature trend. Excessive speed commonly appears as accelerating flank or crater wear, discoloration, loss of dimensional control or a short, repeatable tool life.

3. Set feed from geometry and edge security

Feed controls chip thickness and has a direct effect on productivity and surface finish. Use a lighter feed for a small nose radius or a delicate finishing edge, and use a stronger feed only when the geometry, edge preparation and machine can support it. In milling, verify that the programmed feed is based on feed per tooth and that the effective chip thickness is considered at the actual radial engagement.

If the edge chips at entry or exit, reduce impact before reducing everything: check workholding, lead angle, corner entry and whether the selected geometry is too sharp for an interrupted cut. If the edge is intact but the finish is poor, inspect runout, tool overhang and feed marks before making a large speed change.

4. Select depth of cut for the stock and the machine

Depth of cut should remove the required stock while keeping the cutting edge engaged in a predictable way. A shallow pass can be appropriate for finishing, but an unnecessarily light cut may rub instead of cut, especially on a work-hardened surface. A heavy pass can be efficient in a rigid setup, yet it increases force, deflection and the risk of notch wear.

Observed condition	First adjustment	Why it helps
Chatter or visible deflection	Reduce depth of cut or overhang; then review feed	Lowers cutting force and stabilizes the setup
Rapid flank wear with a stable edge	Reduce speed in a small step	Reduces thermal load without immediately sacrificing chip thickness
Nose chipping at entry or exit	Use a tougher geometry, soften entry, or lower feed at the interruption	Reduces impact loading on the cutting corner
Rubbing, poor finish and no stable chip	Increase feed or depth slightly if the setup is rigid	Keeps the edge cutting instead of repeatedly rubbing the surface

5. Correct for rigidity, coolant and engagement

The same insert can behave differently on a short, rigid toolholder and on a long, flexible setup. Check spindle power, workholding, tool projection, runout and alignment before chasing a parameter. Coolant delivery also matters: a consistent jet can improve chip evacuation and temperature control, while intermittent coolant on a hot carbide edge can increase thermal shock.

In milling, consider radial engagement, axial depth, entry angle and whether the cutter is slotting or side milling. In turning, consider whether the cut is continuous, interrupted, internal or close to a shoulder. These details change the load on the edge even when the nominal speed, feed and depth are unchanged.

6. Run a controlled first-piece test

Set a conservative point inside the recommended data range.
Cut a representative feature using the intended stock and coolant method.
Inspect chip form, sound, surface finish, burrs and dimensional drift.
Measure wear after a defined cutting time or number of parts.
Change one variable at a time and record the result.

Use the evidence to decide whether the next move is speed, feed, depth, geometry or setup. A stable process normally shows gradual wear and repeatable parts; sudden chipping, built-up edge or vibration points to a mismatch that parameter-only changes may not solve.

Turning and milling formula reminders

Turning spindle speed: n = (1000 × v_c) / (π × D), where D is the cutting diameter in mm.

Turning feed rate: feed per minute = f_n × n.

Milling feed rate: feed per minute = f_z × number of teeth × spindle speed.

These formulas convert a selected cutting-data value into machine settings; they do not replace the insert maker’s grade and geometry recommendations. Use the actual diameter and effective engagement, then verify the result on the machine.

JetCutt application checklist

Confirm the workpiece material group, hardness and cutting continuity.
Match insert grade, coating, chipbreaker and nose radius to the operation.
Check holder orientation, tool overhang, runout, coolant and workholding.
Start inside the supplier range and record speed, feed, depth and tool life.
Use chip shape, wear pattern, finish and dimensional results to guide the next trial.

JetCutt’s technical overview and quality and supply information can be used alongside the product range when building an application-specific cutting plan.

Frequently asked questions

Should I increase speed or feed first?

Use the wear evidence. If heat-related wear is accelerating while the edge is intact, test a lower speed. If the edge is stable but productivity or chip thickness is low, test feed in a controlled step. Avoid changing both at once.

Can one cutting-data table be used for every carbide insert?

No. Grade, coating, geometry, nose radius, workpiece condition and machine stability all affect the usable range. Treat published data as a starting window for the exact tool configuration.

Why does a shallow cut sometimes produce a worse result?

If the edge rubs instead of maintaining a stable chip, a light pass can increase heat and work hardening. Check runout and setup, then test an appropriate feed or depth that keeps the edge cutting.

Conclusion

Reliable carbide-insert performance comes from matching cutting speed, feed and depth of cut to the whole machining system. Start with verified tool data, make the first cut deliberately, and use wear and part evidence to refine one variable at a time. This approach supports stable quality, predictable tool life and a safer path to higher productivity.

Technical references: Sandvik Coromant machining formulas and definitions; Seco Tools machining calculators; Sandvik Coromant tool-guided cutting data; Seco Tools geometry guidance.