Ductile-mode Cutting of Cemented Carbide Using Diamond Tools
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Solution Overview
Problem
Current methods for cutting cemented carbide molds for aspherical lenses face inefficiencies and inaccuracies due to tool wear and brittle fracture, particularly in ductile-mode cutting, which limits the reproducibility and precision of machining highly-hard materials like cemented carbide.
Innovation Solution
A cutting method and device utilizing a machining device with precise positioning errors of 5 nm or less in axial directions, combined with a single-crystal or multicrystal diamond tool, and controlled chip thickness between 20 to 60 nm, enabling ductile-mode cutting by maintaining chip thickness within the critical chip thickness range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grinding machining is used to cut cemented carbide, then the material can be processed, but tool wear and brittle fracture occur frequently
Solution Approach 1:
The invention changes the fundamental machining parameters by transitioning from grinding to cutting with a diamond tool, controlling chip thickness to remain below the critical value throughout the entire chip formation process. This parameter change enables ductile-mode cutting of cemented carbide, eliminating brittle fracture and tool wear while achieving continuous chip removal.
2Productivity
If conventional cutting machining is applied to hard and brittle materials, then material removal is achieved, but brittle fracture occurs on the finished surface
Solution Approach 1:
The invention changes the chip thickness parameter to remain consistently below the critical chip thickness throughout the entire chip formation process. This parameter control transforms the material removal mechanism from brittle fracture to plastic deformation, achieving both high productivity and excellent surface quality without cracks or defects.
3Speed
If diamond tool cutting is used for cemented carbide, then cutting speed increases, but the diamond tool becomes abrasively worn by super-hard fine particles
Solution Approach 1:
The invention changes the chip thickness parameter to remain below the critical value, which fundamentally alters the material removal mechanism from abrasive wear to ductile-mode cutting. This parameter control enables the diamond tool to cut cemented carbide at high speeds while maintaining tool life, as the super-hard fine particles are removed through plastic deformation rather than abrasion.
4Productivity
If chip thickness exceeds critical chip thickness during cutting, then material removal is efficient, but brittle fracture occurs instead of ductile-mode cutting
Solution Approach 1:
The invention changes the chip thickness parameter to remain consistently below the critical chip thickness throughout the entire chip formation process. This parameter control enables ductile-mode cutting where material removal occurs through plastic deformation, achieving both efficient material removal and excellent surface integrity without brittle fracture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate and efficient ductile-mode cutting of highly-hard materials like cemented carbide, reducing tool wear and brittle fractures, and achieving smooth surfaces without cracks, thereby improving machining reproducibility and precision.
Implementation Method 1
a material removal mechanism mainly based on plastic deformation is adopted, and that a smooth finished surface without brittle fracture such as cracks can consequently be obtained
Data Source
AI summary
A method of cutting a workpiece made of a highly-hard material is provided. The workpiece is cut by a machining device including a workpiece holder that holds the workpiece, a spindle device that rotates the workpiece holder, a tool holder that holds a tool, and a relative moving mechanism that relatively moves the workpiece holder and the tool holder at least in two axial directions orthogonal to each other. In the machining device, positioning errors in the axial directions are within 5 nm.