Single-Lip Drill Trough Geometry for Chip Breaking and Tool Life
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Solution Overview
Problem
Conventional drilling tools with chip formers have a limited service life when dealing with tough and long-chipping materials, as they tend to weaken the cutting edge and are inefficient in chip formation.
Innovation Solution
A single-lip or two-lip drill design featuring a depression or trough on the cutting surface, where a narrow strip of cutting face remains between the trough and the main cutting edge, enhancing chip formation without weakening the cutting edge, and optionally incorporating a chip breaker to divide the cutting edge into sections, and a wear protection layer for extended durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a chip former is used to improve chip formation, then chip formation is improved, but the cutting edge is weakened and tool life is reduced
Solution Approach 1:
The invention separates the chip formation function from the cutting edge by introducing a groove on the rake face that is spaced away from the cutting edge. The groove forms a chip breaker surface that breaks chips without being part of the cutting edge itself, thus improving chip formation while preserving the integrity and strength of the cutting edge.
Solution Approach 2:
The groove acts as an intermediary element between the cutting edge and the chip flow path. It provides a dedicated chip breaker surface that influences chip formation and breaking without directly compromising the cutting edge structure, serving as a mediator that achieves chip control while protecting the cutting edge.
2Productivity
If a groove is positioned close to the cutting edge to influence chip formation, then chip formation is improved, but the cutting edge is weakened
Solution Approach 1:
The invention applies local quality by creating a groove with specific geometry (width, depth, and spacing) at a specific location on the rake face. The groove is positioned at an optimal distance from the cutting edge to influence chip formation locally without affecting the overall strength of the cutting edge. The narrow strip of rake face remaining between the groove and cutting edge maintains edge integrity while the groove provides localized chip breaking action.
Data Source
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AI summary
The invention relates to single-lip drills (1) and double-lip drills, in which one or more depressions (37) are formed in the cutting surface (23). The depressions (37) according to the invention are arranged in the longitudinal direction of the tool at a distance from the cutting edge and have a positive influence on chip breaking.