Milling Insert Clamping Structure to Prevent Displacement
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Solution Overview
Problem
Conventional milling tools face issues with insufficient clamping force, leading to displacement and potential detachment of cutting inserts during cutting, affecting accuracy and stability.
Innovation Solution
The milling tool design includes a body with an insert attachment portion defined by acute angles and a screw system that enhances clamping force, featuring a sintered cutting edge made of cubic boron nitride or polycrystalline diamond, and a fly-off prevention surface to secure the cutting insert, along with an oil hole for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional bolt and locking piece system is used to attach the cutting insert, then the structure is simple, but the clamping force is insufficient leading to insert displacement and detachment
Solution Approach 1:
The screw hole is formed with an inclined axis at an acute angle relative to the radial direction, creating a curved force application path. This inclined geometry transforms the linear screw tightening force into a multi-directional clamping action that simultaneously presses the insert against both the first and second seat surfaces, significantly enhancing attachment reliability without increasing structural complexity
Solution Approach 2:
The invention transitions from a conventional single-plane clamping system to a three-dimensional multi-surface attachment system. The cutting insert contacts multiple surfaces (first seat surface, second seat surface, and fly-off prevention surface) through the inclined screw hole geometry, distributing clamping force across multiple dimensions and preventing insert displacement more effectively
2Manufacturing precision
If the cutting insert is securely clamped to prevent displacement, then machining accuracy is maintained, but the structure becomes more complex
Solution Approach 1:
The inclined screw hole serves multiple functions simultaneously: it acts as the fastening feature, the clamping force generator, the multi-surface contact guide, and the fly-off prevention mechanism. This multi-functional design achieves high machining accuracy through a single integrated feature rather than multiple separate components, avoiding increased structural complexity
Solution Approach 2:
The insert attachment portion is segmented into multiple functional surfaces (first seat surface for primary support, second seat surface for clamping contact, and fly-off prevention surface for lateral restraint). These segmented surfaces work together through the inclined screw hole to provide comprehensive insert stabilization while maintaining a relatively simple overall structure
3Reliability
If the screw hole is inclined at an acute angle to enhance clamping force, then insert stability is improved, but the manufacturing of the inclined screw hole becomes more difficult
Solution Approach 1:
The invention optimizes the screw hole inclination angle within a specific acute angle range relative to the radial direction. This parameter optimization balances the competing requirements: the angle is steep enough to generate sufficient multi-directional clamping force for insert stability, but not so steep as to make drilling or tapping excessively difficult. The acute angle geometry can be manufactured using standard inclined drilling techniques
Data Source
AI summary
A milling tool includes: a body having an outer circumferential surface formed around a central axis; a cutting insert having a rake surface, a flank surface, and a cutting edge formed by a ridgeline of the rake surface and the flank surface; and a screw attaching the cutting insert to the body. The outer circumferential surface has an insert attachment portion. The insert attachment portion is defined by a first seat surface continuing to the outer circumferential surface and a second seat surface continuing to the first seat surface and having a flat portion provided with a screw hole in which the screw is inserted. The cutting edge is formed of a sintered material containing at least one of cubic boron nitride and polycrystalline diamond. In a cross section perpendicular to the central axis, a first angle formed by a first direction and a second direction is an acute angle.