Drill Cutting Edge Geometry for Strength and Chip Removal
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Solution Overview
Problem
Drills with existing designs face issues of low cutting edge strength and poor chip removability, particularly when drilling non-flat surfaces, leading to potential damage and inefficiencies due to heavy loads and inadequate chip disposal mechanisms.
Innovation Solution
A drill design featuring a cutting edge angled between 85° and 90° with a recess and a rake face having a clearance angle, along with a thinning portion and front clearance, enhancing cutting edge strength and chip removability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the drill tip has a concave shape with a point angle of 170° to 180°, then the drill can process non-flat surfaces with better accuracy, but the outer peripheral portion of the drill tip is likely to be damaged due to heavy load
Solution Approach 1:
The invention applies different geometric characteristics to different parts of the cutting edge. The outer peripheral portion has a larger included angle (170°-180°) for processing non-flat surfaces, while the inner portion has a smaller included angle (90°-100°) for reduced load and improved strength. This local differentiation resolves the contradiction between hole position accuracy and cutting edge strength.
2Manufacturing precision
If the drill tip is a linear cutting edge with a point angle of 180°, then the drill can process non-flat surfaces, but chip removability is poor due to less influence of chip flute on chip disposal
Solution Approach 1:
The invention creates a non-linear cutting edge geometry where the inner portion has a smaller included angle that enhances chip flute influence on chip disposal. This local geometric variation improves chip removability while the outer portion maintains the larger angle for non-flat surface processing accuracy.
Data Source
AI summary
Provided is a drill having a flat-shaped drill tip and excellent in cutting edge strength and chip removability. The drill includes: a cutting edge extending in a direction at an angle α of not less than 85° and not more than 90° with respect to a drill axis (line O-O); a flank face contiguous to the cutting edge and having a clearance angle β of not less than 5° and not more than 10° with respect to the drill axis (line O-O); and a rake face located opposite to the flank face across the cutting edge, the cutting edge includes a recess receding in a direction parallel to the drill axis (line O-O), and the rake face includes a front clearance formed at a side of an outer periphery of the drill.