PCD & CBN Tools Wear Modes, Failure Diagnosis and Regrinding

August 17, 2026 · Exactalloy Technical Team

Every premature failure has a signature. Reading it saves far more than tightening a tolerance on paper.

Quick answer: Flank wear is normal and progressive; chipping means rigidity or geometry; built-up edge means speed too low or coating too reactive; thermal cracks mean interrupted coolant. Regrind at a wear land of 0.2–0.3 mm.

Normal wear

Flank wear grows predictably with cutting time — set a wear-land limit and change tools on a schedule rather than on a hunch.

Chipping and breakage

Trace it to run-out, insufficient coolant, too aggressive a feed or a workholding weakness before blaming the tool.

Built-up edge

Raise surface speed, switch to a smoother coating, or use a sharper positive geometry.

Thermal cracking

Caused by cycling coolant on and off — keep coolant continuous or go fully dry, never intermittent.

Specifications at a glance

Symptom	Likely cause	Action
Uniform flank wear	Normal	Regrind at 0.2–0.3 mm
Chipping	Run-out / vibration	Check holder, reduce feed
Built-up edge	Speed too low	Raise vc, change coating
Thermal cracks	Intermittent coolant	Continuous or dry
Colour burn on edge	Speed too high	Reduce vc, improve cooling

Frequently asked questions

When should I regrind instead of replace?

When a regrind restores the original geometry and costs well under the price of a new tool — typically two to four regrinds per carbide tool.

Does regrinding change the diameter?

Yes — controlled regrinding reduces diameter slightly, so compensate offsets in the control.

Get a quote and technical support

Exactalloy supplies PCD and CBN cutting tools from stock, made-to-order and reground. Send your drawing or specification for a quotation and lead time within 24 hours. Contact us or browse all products.