Rotary Drill Cutting Head with Segmented Corner Bevels
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Solution Overview
Problem
Rotary cutting tools face high mechanical and thermal loading at the cutting corner, leading to reduced service life and increased burr formation during through-openings, requiring additional secondary cutting edges for re-working.
Innovation Solution
A rotary tool design featuring two main cutting edges with differently configured corner bevels, a larger roughing bevel for initial machining and a smaller finishing bevel for re-work, eliminating the need for secondary cutting edges and enhancing service life while minimizing burr formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a corner bevel is provided at the cutting corner, then the service life of the cutting tool is increased, but burr formation at the exit of the drill hole is increased
Solution Approach 1:
The corner bevel is segmented into two distinct parts: a first corner bevel (roughing bevel) and a second corner bevel (finishing bevel). The first corner bevel has a larger angle (45-60 degrees) to reduce mechanical loading and extend tool life, while the second corner bevel has a smaller angle (10-30 degrees) to minimize burr formation. This segmentation allows each bevel to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different regions of the cutting corner are given different geometric properties through the two corner bevels. The first corner bevel region is designed with a larger angle for roughing and load distribution, while the second corner bevel region is designed with a smaller angle for finishing and burr reduction. This local differentiation of geometric quality enables simultaneous achievement of extended tool life and reduced burr formation.
2Object-generated harmful factors
If additional secondary cutting edges are added to re-work the hole exit, then burr formation is reduced, but device complexity increases
Solution Approach 1:
The functions of roughing and finishing at the cutting corner are merged into a single integrated structure with two corner bevels, eliminating the need for separate secondary cutting edges. The first and second corner bevels work together in sequence during the cutting operation, with the first bevel performing roughing and the second bevel performing finishing, thereby achieving burr reduction without increasing tool complexity.
Solution Approach 2:
The dual-corner-bevel structure serves multiple functions simultaneously: it reduces mechanical and thermal loading (extending tool life), minimizes burr formation, and maintains simple tool geometry. By making the cutting corner multi-functional through geometric design rather than adding separate components, the invention achieves burr reduction without increasing device complexity.
Data Source
AI summary
In order to provide a rotary tool, in particular a drill, with a long service life together with high-quality drill holes, particularly in the case of through bores, the invention provides a cutting head which extends along a rotational axis and has a plurality of main cutting edges which extend radially outwards and each end at a cutting corner having a corner bevel, wherein the corner bevels are of differing designs, specifically in the form of a roughing bevel and in the form of a finishing bevel.