Diagnosing Insert Wear - Causes, Signs, and Remedies

Diagnosing insert wear - causes, signs, and remedies

October 6, 2025
By Sandvik Coromant, for the Blue Print

Every cutting tool is subject to wear, and while some amount is inevitable, the way it develops and the speed at which it progresses can have a major impact on machining performance. Excessive wear can shorten tool life, reduce accuracy, and lead to unplanned downtime — driving up costs and cutting into productivity. By learning to recognize common wear patterns and what causes them, you gain the ability to spot problems earlier and take action to extend tool life, reduce interruptions, and keep performance consistent.

This article is designed as an easy-to-use reference for identifying typical insert wear types, understanding their causes, and applying practical solutions to minimize their impact.

Flank Wear: Flank wear is one of the most common wear types and it occurs on the flank face of the insert (tool).

Cause - During cutting, tool material is lost on the flank face due to it sliding against the surface of the newly cut workpiece material. This wear type normally begins at the edge line and then gradually develops downward, perpendicular to the edge line.
Remedy - Reducing the cutting speed and simultaneously increasing the feed will result in increased tool life with retained productivity.

Plastic Deformation: Plastic deformation is a permanent change in the shape of the cutting edge, where the edge has either suffered an inward deformation (edge impression) or a downward deformation (edge depression).

Cause - This type of wear occurs when the cutting edge is simultaneously subjected to high cutting forces and high temperatures resulting in a stress state in the edge exceeding the tool materials yield strength at the given temperature.
Remedy - Plastic deformation can be dealt with by using grades with higher hot hardness. Coatings improve the plastic deformation resistance of the insert (tool).

Cracks: A crack is a narrow opening in which new boundary surfaces have been formed through rupture. Some cracks are confined to the coating, while others extend down into the substrate. Comb cracks are roughly perpendicular to the edge line and most often thermal cracks.

Cause - Comb cracks form as a result of rapid fluctuations in temperature.
Remedy - To prevent this, a tougher insert grade can be used and the coolant should be applied copiously or not at all.

Fracture: A fracture is defined as the breakout of a large part of the cutting edge, where the insert can no longer be used.

Cause - When a fracture occurs, the cutting edge has been exposed to a greater load than it can resist. This could be the result of allowing the wear to progress too far leading to increased cutting forces. A fracture could also be caused before the insert is even significantly worn due to the wrong cutting data.
Remedy - Identify and prevent the original wear type or select another cutting data.

Crater Wear: Excessive crater wear causing a weakened edge and poor surface finish.

Cause - Crater wear occurs as a result of the chip contact with the rake face of the insert (tool). Tool material is being removed from the insert (tool) which leads to the gradual formation of a cavity, or a crater.
Remedy - Lowering the cutting speed and choosing an insert (tool) with the right geometry and a more wear resistant coating will increase the tool life.

Built-up edge: Built-up edge (BUE) is an accumulation of material against the rake face.

Cause - Built up workpiece material can form a cutting edge on top of the original edge, which separates the tool from the material. One of the problems with BUE is that when it sooner or later rips off, it can in worst case also take away parts of the coating and even substrate.
Remedy - Increasing the cutting speed can prevent the formation of BUE.

Chipping: Chipping consists of minor damage to the edge line. The difference between chipping and fracture is that with chipping the insert can still be used.

Cause - There are many wear mechanisms and combinations of wear mechanisms that can cause chipping. However, the most commonly occurring wear mechanisms are thermo-mechanical and adhesive.
Remedy - Different preventative measures can be taken to minimize chipping, depending on which wear mechanism/mechanisms that caused it.

Notch wear: Notch wear is characterized by excessive localized damage at maximum cutting depth but can also occur on secondary edge.

Cause - The growth of notch proceeds differently depending upon the wear mechanisms. If the chemical wear mechanism dominates the notch wear proceeds more regularly, as in the picture, compared to irregular growth when adhesive or thermo-mechanical wear mechanisms dominate. In the latter case work hardening of the workpiece material and burr formation are important factors for the notch growth.
Remedy - For work-hardening materials, select a smaller entering angle and/or vary the depth of cut.

Insert wear may be inevitable, but it doesn’t have to be unpredictable. By understanding the different wear mechanisms, their causes, and the remedies available, you gain the ability to spot problems earlier and take corrective action with confidence. This knowledge not only helps extend tool life and reduce downtime, but also supports more consistent results, improved productivity, and greater cost-efficiency across machining operations.

Keep this guide in mind as a reference whenever wear challenges arise — a small step toward keeping operations running smoothly.

Content originally from Sandvik Coromant. Reused here with permission.

Diagnosing insert wear - causes, signs, and remedies

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