Segmented Indexable Drill Inserts for Stable Hole Accuracy
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Solution Overview
Problem
Conventional indexable drill inserts with rectangular cutting edges tend to drift from their center due to uneven cutting force distribution, leading to suboptimal hole drilling, especially when the hole diameter is smaller than desired, resulting in narrow walls and surface rubbing issues.
Innovation Solution
The design features drilling inserts with four cutting edges, each comprising multiple segments and a wiper edge, angled to provide effective chip breaking and stable corner edges, allowing for better support within the drilling body's pocket, and a system of central and peripheral inserts with specific orientation and positioning to maintain cutting diameter consistency across varying diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional rectangular cutting edges are used, then the drilling insert structure is simple, but the drill drifts away from its center due to uneven force distribution
Solution Approach 1:
Each cutting edge is divided into multiple segments (first cutting edge segment, second cutting edge segment, and wiper edge segment) arranged at different angles. This segmentation allows each segment to bear specific portions of the cutting force, distributing the load more evenly across the insert and preventing drill drift while maintaining structural simplicity.
Solution Approach 2:
Different segments of the cutting edge are designed with different orientations and functions. The first and second cutting edge segments are positioned at specific angles to optimize cutting performance, while the wiper edge segment is positioned to provide surface finishing. This local differentiation of quality and function improves hole center accuracy without significantly increasing overall complexity.
2Ease of manufacture
If rectangular cutting edges are used, then the insert design is straightforward, but narrow walls are created which are not feasible in practical applications
Solution Approach 1:
The cutting edge is segmented into multiple portions with different orientations. The first cutting edge segment extends at a first angle, the second cutting edge segment extends at a second angle, and the wiper edge provides a finishing surface. This segmentation enables the creation of holes with wider, more practical wall geometries while maintaining ease of manufacture through modular segment design.
3Device complexity
If conventional cutting edges are used, then the insert structure is simple, but the drill rubs the surface of the drilled hole when diameter is less than desired
Solution Approach 1:
The cutting edge is divided into segments including a dedicated wiper edge segment positioned at a specific angle. This wiper segment acts as a separate functional element that cleans and finishes the hole surface as the insert rotates, eliminating surface rubbing without significantly increasing overall device complexity.
Solution Approach 2:
The wiper edge segment is specifically positioned and oriented to contact the hole surface at the appropriate location and angle. This local specialization of function ensures that surface rubbing is prevented while maintaining a relatively simple overall insert structure.
4Productivity
If all sides of an insert are used for cutting, then productivity is improved, but corner edges become weak without proper angling
Solution Approach 1:
Each corner of the insert features a corner edge portion formed by the intersection of adjacent cutting edges with different angle segments. This segmentation allows each corner to be reinforced by the geometric intersection of angled segments, strengthening the corner edges while enabling all four sides of the insert to be used for cutting, thereby improving productivity.
Data Source
AI summary
Drilling tool systems including a drilling body and a drilling inserts are disclosed. The drilling inserts include four indexable cutting edges. The four cutting edges may each comprise a plurality of cutting edge segments and a wiper edge. The plurality of cutting edge segments and the wiper edge are provided at distinct angles to provide effective chip breaking and a stronger cutting edge at the drilling insert corners. Furthermore, the side surfaces of the drilling inserts allow the drilling insert to be more stably supported in a pocket of the drilling body. The drilling inserts may be used in a peripheral pocket of a drilling body.