Cutting Insert Pocket Structure to Prevent Rotation and Cracking
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Solution Overview
Problem
Existing cutting tools and inserts face challenges in providing adequate support to cutting inserts during machining, leading to potential rotation and cracking under cutting forces, especially in active chip-removing states, and restrict the use of reversible inserts.
Innovation Solution
The cutting tool features a raised support face with projecting members that extend to the periphery of the insert, providing enhanced support and stability, allowing for reversible inserts and improved resistance to cracking by positioning the support face near the cutting edge's maximum load area, with two projecting members improving stability and facilitating easy mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a flat pocket bottom surface is used as the support face, then the insert can be supported from below, but the insert cannot be properly supported on the sides leading to rotation and cracking under cutting forces
Solution Approach 1:
The support face is segmented into multiple levels: a first support face at the pocket bottom and a second support face on the raised portion. This segmentation allows different regions of the insert to be supported at different heights, providing both bottom support and side support to prevent rotation and cracking under cutting forces.
Solution Approach 2:
The support system transitions from a two-dimensional flat pocket bottom surface to a three-dimensional structure with a raised portion. This adds vertical dimensionality, creating a second support face that extends upward to provide lateral support to the insert's side surface, thereby preventing rotation and improving stability under cutting loads.
2Ease of manufacture
If the support face is positioned away from the insert periphery, then the insert mounting is simplified, but the insert lacks adequate support near the cutting edge leading to cracking
Solution Approach 1:
The raised portion is positioned locally at a specific region of the pocket, creating a second support face that extends toward the insert periphery. This localized structural enhancement provides targeted support near the cutting edge where cutting forces are highest, preventing cracking while maintaining simplified mounting through the engagement member clearance.
3Strength
If the insert seating surface is extended to the periphery, then support is improved, but the insert cannot be rotated for indexing
Solution Approach 1:
The raised portion is designed with an asymmetric profile relative to the insert, creating a second support face that provides lateral support while leaving specific regions clear for engagement members. This asymmetric design enables both peripheral support and rotational indexing by allowing engagement members to clear the raised portion during rotation.
Solution Approach 2:
The engagement member acts as an intermediary between the insert and the pocket's raised portion. It provides the necessary clearance to allow insert rotation and indexing while the raised portion maintains its support function. The engagement member mediates between the conflicting requirements of peripheral support and rotational capability.
4Device complexity
If a single projecting member is used for engagement, then the structure is simpler, but the insert stability under rotational moment is insufficient
Solution Approach 1:
The engagement system is segmented into multiple engagement members distributed around the insert perimeter. This segmentation distributes the rotational moment loads across multiple contact points, significantly improving insert stability under cutting forces while maintaining relatively simple individual engagement member structures.
Data Source
Figure 1
Figure 2~4
AI summary
A cutting tool has a tool body having at least one pocket (3), at least one cutting insert releasably fixed to the pocket and fastening means for securing the insert in the pocket. The pocket has a raised portion (20) with a flat upper support face (22) to be received in a recess of an insert and support the insert by receiving a bottom surface of the recess bearing on the support face (22). A projecting member (25) of the raised portion (20) has delimiting walls (29) designed to bear against border walls of a said recess of an insert for establishing mutual contact therewith and prevent rotation of the insert in the pocket by receiving a rotational moment acting on the insert in an active chip-removing state of the tool.