Thread Milling Cutter Edge Geometry to Resist Deflection
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Solution Overview
Problem
Thread milling cutters tend to deflect due to radial forces applied by the workpiece, leading to reduced tool life.
Innovation Solution
The thread milling cutter design includes end cutting edges with specific angles and dimensions to enhance axial bracing and reduce cutting resistance, featuring a first end cutting edge with an angle of 6° or less and a second end cutting edge angled more towards the rear, along with a diameter configuration that balances cutting forces and minimizes wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If end cutting edges are added to eliminate pre-drilling, then productivity is improved, but deflection increases due to radial force
Solution Approach 1:
The patent changes the geometric parameters of the end cutting edges, specifically setting the angle between the first end cutting edge and the imaginary plane perpendicular to the axis at 6° or less. This parameter optimization strengthens the axial bracing force while managing radial forces, allowing simultaneous drilling and threading without excessive deflection.
Solution Approach 2:
The end cutting edges are segmented into two distinct parts: a first end cutting edge with a specific angle (6° or less) connected to the thread cutting edge, and a second end cutting edge angled more toward the rear end. This segmentation allows each part to perform different functions - the first edge provides axial bracing while the second reduces cutting resistance.
2Force
If the first end cutting edge angle is set to 6° or less, then axial bracing force is strengthened, but cutting resistance increases
Solution Approach 1:
The end cutting edges are divided into two segments with different angular orientations. The first end cutting edge (at 6° or less) generates axial bracing force, while the second end cutting edge (angled more toward the rear end) reduces cutting resistance. This segmentation allows the tool to simultaneously achieve strong axial support and reduced cutting resistance.
Solution Approach 2:
Different portions of the end cutting edges are given different geometric properties. The first end cutting edge has a shallow angle optimized for axial bracing, while the second end cutting edge has a steeper angle optimized for reducing cutting resistance. Each local region is optimized for its specific function.
3Force
If the diameter at the boundary between thread cutting edges and first end cutting edges is set to minor diameter, then axial bracing force location is optimized, but tool complexity increases
Solution Approach 1:
The patent specifies a particular parameter value for the diameter at the boundary between thread cutting edges and first end cutting edges, setting it equal to the minor diameter of the thread. This parameter optimization positions the axial bracing force outward, improving tool stability without requiring complex additional structures.
Data Source
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AI summary
Provided is a thread milling cutter with a long tool life. A plurality of threads projecting in directions perpendicular to the axis from a front end side of an outer circumference of the tool body(10) to form thread cutting edges(20a,24,29).The end cutting edges (33) formed on the front end face of the tool body includes a first end cutting edge (34) that is connected to the front end of the thread cutting edge, and a second end cutting edge (35) that is connected to the first end cutting edge on the side closer to the axis (C), and is angled more toward the rear end than the first end cutting edge. The angle (θ1) formed by an imaginary plane (P) perpendicular to the axis and the first end cutting edge is set to 6° or less. The angle (θ2) formed by the second end cutting edges and the imaginary plane perpendicular to the axis and is set to be greater than the angle formed by the first end cutting edges and the imaginary plane perpendicular to the axis.