How to Choose the Right Carbide Insert？
Choosing the correct carbide insert is critical for achieving stable machining, improving surface finish, and extending tool life. Whether you are turning steel, stainless steel, cast iron, or non-ferrous metals, the right insert geometry and grade directly affect your machining efficiency.
1. Select the Insert Shape
Common insert shapes include CNMG, TNMG, SNMG, and WNMG.
CNMG / SNMG – High strength, suitable for roughing.
TNMG – Balanced versatility for finishing and roughing.
WNMG – Low cutting resistance, ideal for stainless steel.
2. Choose the Proper Chip Breaker
Chip control determines cutting stability:
Finishing breaker – Thin chip, low feed.
Medium breaker – General applications.
Roughing breaker – Large chip load, high durability.
3. Select the Right Insert Grade (Coating / Substrate)
Different materials require different carbide grades:
Steel (P-grade) – Wear-resistant coating, excellent toughness.
Stainless steel (M-grade) – Anti-built-up-edge, smooth cutting.
Cast iron (K-grade) – High hardness, strong wear resistance.
Non-ferrous (N-grade) – Sharp cutting edge, no coating.
General purpose – Balanced toughness + wear resistance.
4. Match Insert to Workpiece Material
Each material behaves differently during machining:
Steel – Need high toughness, stable wear resistance.
Stainless steel – Require sharp edges + anti-adhesion coating.
Cast iron – Prefer harder grades and solid edges.
Aluminum / Copper / Plastics – Mirror-polished sharp inserts.
5. Consider Cutting Parameters
Insert selection depends on:
Cutting speed
Feed rate
Depth of cut
Machine rigidity
With the right combination of insert shape, breaker, grade, and cutting conditions, you can greatly enhance machining stability and productivity.
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