Segmented Drill Point Geometry for Burr-Suppressed Hole Drilling
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Solution Overview
Problem
Conventional drills often leave burrs around drilled holes due to cutting conditions such as high-speed rotation and high-speed feed, regardless of the work material type, necessitating additional deburring processes.
Innovation Solution
A drill design featuring specific cutting edges and flanks, including thinning faces, major cutting edges, and curved or straight fourth cutting edges, with controlled point angles and clearance angles to suppress burr formation by finely dividing and discharging chips effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed rotation and high-speed feed cutting conditions are used, then drilling productivity is improved, but burr formation around drilled holes increases
Solution Approach 1:
The drill point is segmented into multiple distinct cutting edges (first, second, third, and fourth cutting edges) with different functions. The third and fourth cutting edges specifically address burr formation by controlling chip discharge at the exit side, while maintaining high-speed cutting capability through the first and second cutting edges.
Solution Approach 2:
Different regions of the drill point are given different geometric properties. The first and second cutting edges have specific point angles for efficient cutting, while the third and fourth cutting edges have extended lengths and specific clearance angles to control chip flow and suppress burrs at the critical exit region.
2Ease of manufacture
If conventional drill designs are used, then manufacturing simplicity is maintained, but burr suppression capability is insufficient
Solution Approach 1:
The drill design incorporates preliminary actions to prevent burr formation during the drilling process. The third and fourth cutting edges are positioned and angled to control chip discharge before the chips can cause burrs, proactively preventing the harmful effect rather than addressing it after formation.
3Object-generated harmful factors
If extended third and fourth cutting edges are added, then burr suppression is improved, but drill point complexity increases
Solution Approach 1:
The third and fourth cutting edges are merged with the existing drill point structure, extending from the second cutting edge rather than being separate components. This integration achieves burr suppression functionality while minimizing additional complexity compared to a completely separate burr-control mechanism.
Data Source
AI summary
There is provided a drill including cutting edges wherein each of the cutting edges includes a first cutting edge extending outward in the radial direction from a chisel edge, a second cutting edge having a straight part extending outward in the radial direction from the first cutting edge, a third cutting edge extending outward in the radial direction and extending in a circumferential direction and toward a rear of the drill from the second cutting edge, and a fourth cutting edge extending toward the rear of the drill from the third cutting edge and connected to a leading edge. A first point angle α1 formed by the first cutting edge is set not larger than a second point angle α2 formed by the second cutting edge, and the first point angle α1 formed by the first cutting edge is set within the range of 90° to 140°.