Thread Mill Cutting Edge Layout to Reduce Internal Thread Tilting
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Solution Overview
Problem
Existing thread mills experience tilting of internal threads at an early stage due to excessive small cutting amounts per rotation, leading to reduced tool life, especially under certain cutting conditions.
Innovation Solution
A thread mill design with functional and non-functional cutting edges, where non-functional edges are relieved towards the shank end, and gashes are formed to house chips, reducing load concentration and ensuring uniform cutting amounts and reaction forces, thus minimizing tilting and increasing tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all end cutting edges are made functional to maximize material removal, then productivity increases, but tilting of internal thread increases and tool life decreases
Solution Approach 1:
The end cutting edges are differentiated into functional cutting edge portions and non-functional cutting edge portions. The functional portions actively cut the workpiece to remove material, while the non-functional portions are relieved toward the shank end to prevent contact and cutting. This local differentiation allows some cutting edges to contribute to productivity while others prevent tilting, resolving the contradiction between material removal rate and tool life.
2Reliability
If cutting amount per rotation is increased to reduce tilting, then tool life increases, but the complexity of cutting edge design increases
Solution Approach 1:
Each end cutting edge is segmented into a functional cutting edge portion and a non-functional cutting edge portion. The functional portion is positioned to actively engage and cut the workpiece, removing material effectively. The non-functional portion is relieved toward the shank end, positioning it above the cutting trajectory to prevent contact. This segmentation allows the tool to achieve sufficient cutting amount per rotation to reduce tilting and extend tool life, while maintaining a relatively simple overall structure that integrates seamlessly into the thread mill body.
Data Source
AI summary
Provided is a thread mill that can reduce tilting of an internal thread to be machined, thus increasing the tool life. A thread mill includes a plurality of thread cutting edges that are circumferentially spaced apart on a front end side of an outer circumference of a tool body, and a plurality of end cutting edges formed at the front end of the tool body. A functional cutting edge portion that cuts a workpiece, and a non-functional cutting edge portion that is relieved toward an axial shank end relative to a trajectory of the functional cutting edge portion when the tool body is caused to make one rotation about an axis are formed on the plurality of end cutting edges.