Segmented Indexable Drill Insert for Centering and Chip Breaking
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Solution Overview
Problem
Conventional quadrangular indexable drill inserts with four cutting edges often drift away from the center due to unbalanced forces, causing them to rub against the drilled hole surface, especially when the hole diameter is less than the desired value.
Innovation Solution
The design features a drilling insert with four cutting edges, each comprising multiple segments at distinct angles, providing effective centering, penetration, and chip breaking, with side surfaces that stabilize the insert in the drilling body, preventing drifting and ensuring precise cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional quadrangular indexable drill inserts with four cutting edges are used, then the drilling operation can be performed, but the drill drifts away from its center due to unbalanced forces
Solution Approach 1:
Each cutting edge is divided into multiple cutting edge segments (first, second, and third segments) arranged at distinct angles. This segmentation allows each segment to contribute differently to the cutting action, with the first segment engaging the workpiece at a smaller angle for initial penetration and centering, while subsequent segments complete the cutting action, thereby balancing the forces and preventing drill drift
Solution Approach 2:
Different portions of the cutting edge are given different geometric properties through the segmented design. The first cutting edge segment has specific angular orientation to provide effective centering and penetration, while the second and third segments are oriented to provide chip breaking and finishing. This local differentiation of cutting edge properties ensures balanced force distribution across the cutting edge
2Productivity
If conventional indexable drill inserts are used, then cutting can be performed, but the insert rubs the surface of the drilled hole when the hole diameter is less than the pre-desired value
Solution Approach 1:
The cutting edge is segmented into multiple portions with different angular orientations. The first segment engages the workpiece at a controlled angle that allows proper centering and penetration before the full diameter is reached, preventing the cutting edge from rubbing against the hole surface. The segmented design ensures that cutting action begins properly even when the hole diameter is less than the final desired value
Solution Approach 2:
The first cutting edge segment is designed to perform preliminary centering and penetration action before the other segments engage fully. This preliminary action establishes proper hole formation from the beginning of the drilling operation, preventing surface rubbing as the hole grows to its final diameter
3Productivity
If conventional drill inserts with four cutting edges are used, then drilling can be performed, but unbalanced forces cause the drill to drift
Solution Approach 1:
By dividing each cutting edge into multiple segments oriented at distinct angles, the cutting forces are distributed more evenly around the drill axis. The first segment engages at a smaller angle to provide initial stability, while subsequent segments contribute to the cutting action in a balanced manner, maintaining drill stability throughout the drilling operation
Solution Approach 2:
The cutting edge segments are arranged at distinct asymmetric angles rather than symmetric configurations. This asymmetric arrangement of segments at different angular orientations creates a more balanced force distribution pattern that prevents lateral forces from causing drill drift, thereby improving drill stability
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. The plurality of cutting edge segments are provided at distinct angles with respect to a reference plane of the drilling insert 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 central pocket of a drilling body.