Three-Edge Flat Drill Geometry for Stable Chip Removal
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Solution Overview
Problem
Existing flat drills face challenges in stability, service life, centering, and chip removal efficiency, particularly when drilling hard or difficult materials.
Innovation Solution
A flat drill design with three main cutting edges, each converging at the drill axis, featuring a point thinning correction and crescent-shaped course, along with optimized chip angles and clearance angles, to distribute stress and improve chip removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If main cutting edges are arranged at 180° tip angle in one plane, then flat hole base is achieved, but drill stability and service life are reduced
Solution Approach 1:
The patent applies asymmetry by arranging the three main cutting edges at different radial positions around the drill axis, with tip angles of 120° between adjacent edges. This asymmetric configuration prevents the cutting edges from lying in a single plane, thereby improving drill stability and service life while still achieving a flat hole base through the coordinated action of all three cutting edges.
2Ease of manufacture
If point thinning is applied to correct chip angle, then reliable chip removal is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by implementing point thinning only in specific regions of the main cutting edges where chip flow requires correction. Rather than modifying the entire cutting edge geometry, the point thinning is localized to particular segments, achieving reliable chip removal while minimizing the increase in manufacturing complexity.
3Reliability
If three main cutting edges are used instead of two, then stress distribution and service life are improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the cutting function into three separate main cutting edges instead of two, with each edge bearing approximately one-third of the cutting load. This segmentation of the cutting function improves stress distribution and service life, while the regular 120° spacing maintains a relatively simple and balanced device structure.
Data Source
AI summary
A flat drill (1) with a shank (6) and a cutting part (8) with front-side main cutting edges (16), which each extend in a plane transversely to the drill axis (3) from a cutting edge corner (22) into the drill center. The flat drill (1) has exactly three main cutting edges (16), which converge at the drill axis (3).