Tangential Milling Insert Geometry for Sintering Distortion Control
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Solution Overview
Problem
Milling inserts made of cemented carbide often experience unpredictable distortion during sintering due to denser regions adjacent to the clamping bore, leading to undesirable surface irregularities, particularly bulges on abutment surfaces.
Innovation Solution
A reversible and indexable triangular tangential milling insert with a non-twisted geometry, featuring a clamping bore and concavely curved minor abutment surfaces that converge outwardly, reducing distortion and enhancing chip flow and stability during machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a clamping bore is included in the milling insert, then the insert can be securely clamped and retained during machining, but denser regions adjacent to the bore cause unpredictable distortion and surface irregularities during sintering
Solution Approach 1:
The patent applies local quality by creating a non-uniform density distribution within the insert body. Specifically, the insert is designed with a first density region and a second density region having different densities, with the second region having lower density than the first. This localized density variation compensates for the densification that occurs during sintering near the clamping bore, preventing distortion and maintaining surface accuracy while preserving the clamping retention provided by the bore.
2Productivity
If traditional sintering is used to produce the insert, then the carbide powder can be compacted and sintered efficiently, but volume decrease and distortion occur in regions adjacent to the clamping bore
Solution Approach 1:
The patent applies parameter changes by modifying the density parameter of the insert material in specific regions. The insert comprises a first density region and a second density region with different densities, where the second region has lower density than the first. This density parameter variation is implemented to compensate for the volume decrease that occurs during traditional sintering, thereby maintaining geometric stability and preventing distortion in regions adjacent to the clamping bore while preserving sintering efficiency.
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
The solution minimizes surface distortion during sintering and improves the operational lifespan and chip flow efficiency of the milling insert by maintaining a robust, non-twisted design and optimized abutment surface geometry.
Implementation Method 1
A common process of producing a milling insert includes compaction of a carbide powder mixed with a binder, followed by sintering
Data Source
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AI summary
A reversible and indexable tangential milling insert includes two major surfaces and a peripheral surface which extends therebetween. The milling insert includes a mid-plane (M) located midway between the major surfaces, and an insert clamping bore with a central bore axis (H). The peripheral surface includes three side surfaces, each of which includes exactly two cutting portions, two relief portions and two minor abutment surfaces located on opposite sides of the mid-plane (M), each continuously extends between respective cutting portion and relief portion. Each cutting portion includes a major cutting edge, a minor cutting edge, and a corner cutting edge. In a cross section along a first imaginary plane perpendicular to the bore axis (H), each minor abutment surface is concavely curved, and on each side surface, the minor abutment surfaces converge outwardly.