Tool passivation is a way to extend cutting tool life. It improves tool quality through processes like flattening, polishing, and deburring. This is actually a normal step in cutting tool manufacturing after grinding and before coating.
What is cutting tool passivation？
It improves tool quality through processes like flattening, polishing, and deburring. This is a normal step in tool manufacturing after grinding and before coating.
Why Cutting tools Undergo Passivation Treatment？
After grinding with conventional or diamond wheels, cutting tool edges exhibit microscopic defects like microchipping and serration to varying degrees. During cutting, these edge imperfections readily propagate leading to accelerated cutting tool wear and failure.
Modern high-speed machining and automated machine-cutting tools place greater demands on cutting tool performance and consistency. Especially for coated cutting tools, pre-coating edge passivation is crucial to ensure coating integrity and cutting tool life.
The Purpose of Cutting tool Passivation
The purpose of edge passivation technology is to address the microscopic defects present on cutting edges after grinding, reducing or eliminating the serrated irregularities to make the edges smooth and uniform. This achieves sharp and strong edges with lasting durability.
The Main Effects of Cutting tool Passivation
Edge rounding: Removing edge burrs and achieving precisely consistent edge radii.
Edge burrs cause cutting tool wear and poor workpiece surface finish. Stoned edges are very smooth, greatly minimizing chipping. This also improves workpiece surface quality.
Polishing of chip grooves:
Uniformly polishing the cutting tool grooves improves surface quality and chip evacuation.
Smoother groove surfaces facilitate better chip removal, enabling higher cutting speeds. Improved surface quality also reduces risks of work material adhesion and built-up edge. Cutting forces can be reduced by 40%, resulting in smoother cutting.
Polishing of coatings:
Removing coating droplets and increasing surface finish improves lubricant retention.
Coated cutting tools can have small coating protrusions that increase surface roughness. This generates higher friction and heat during cutting, limiting speeds. Passivation removes droplets and leaves small pits that retain more cutting fluid. This greatly reduces heat to significantly increase machining speeds.
Why Cutting Tools Undergo Passivation Treatment?
Passivation removes microscopic edge defects and increases edge strength and cutting tool life.
What are the main methods for cutting tool passivation?
Common methods are manual stone rubbing, mechanical abrasive belt passivation and polishing.
What is the optimal abrasive for passivation?
Generally, superfine abrasives around 100-600 grit or diamond laps are used.
What should be noted during passivation?
Use light pressure to avoid excessive edge wear. Dress the stones frequently.
What are the effects of passivation?
It can improve fracture resistance, prolong life, reduce cutting forces, and improve chip evacuation.
Which cutting tools need passivation?
Carbide, ceramic and PCD/CBN cutting tools typically require passivation.
What is the relation between passivation and coating?
Passivation removes defects and improves coating adhesion and retention.