Helical Drill With Symmetric Cutting Edges For Flat Bottom Holes
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Solution Overview
Problem
Existing cutting tools for creating flat bottom holes often result in weakened areas, excessive wear, and high cutting forces due to inefficient chip formation and control, leading to drill breakage and deviations in hole formation.
Innovation Solution
A helical cutting tool with symmetrically oriented cutting edges, a central chisel edge, and positive axial rake angles, along with chip discharge flutes for efficient chip removal, is designed to provide stability and reduce thrust during drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If prior art flat bottom cutting drills are configured to form flat bottom holes, then the desired flat bottom hole shape is achieved, but the drills experience weakened areas that lead to breakage or fracture
Solution Approach 1:
The cutting edge is divided into multiple discrete segments or insert elements rather than a continuous traditional cutting edge. This segmentation allows each segment to be independently optimized for strength while maintaining the overall flat bottom hole formation capability, thereby preventing drill breakage at weakened areas.
Solution Approach 2:
The drill incorporates composite structure combining hard cutting elements (such as carbide inserts) with tougher matrix material. This composite construction provides both the hardness needed for precise flat bottom hole formation and the toughness to prevent catastrophic failure, resolving the contradiction between manufacturing precision and reliability.
2Manufacturing precision
If prior art drills are configured for flat bottom hole formation, then the hole shape is achieved, but chip formation and removal become inefficient causing excessive wear
Solution Approach 1:
The drill features dynamic chip breakers and variable pitch helical flutes that actively manage chip flow during drilling. These dynamic elements adapt to different drilling conditions to optimize chip evacuation, preventing chip clogging and reducing wear on cutting edges, thereby extending drill life while maintaining flat bottom hole precision.
Solution Approach 2:
Chip breakers and flute geometries serve as intermediary elements between the cutting edge and chip discharge path. These intermediaries facilitate efficient chip formation and removal by controlling chip flow patterns, reducing direct contact between chips and cutting edges, and minimizing wear while preserving flat bottom hole accuracy.
3Manufacturing precision
If prior art cutting edges are designed for flat bottom hole formation, then the hole shape is achieved, but cutting forces become excessively high
Solution Approach 1:
The drill incorporates optimized helical angle, flute pitch, and cutting edge geometry parameters that reduce cutting thrust while maintaining flat bottom hole formation. By carefully selecting and adjusting these geometric parameters, the drill achieves lower cutting forces without sacrificing hole shape precision.
Solution Approach 2:
The cutting edges and flutes incorporate curved and helical geometries rather than straight rigid forms. These curved paths allow for more gradual material engagement and reduced shock loads, decreasing cutting thrust while effectively forming flat bottom holes through the rotational motion and curved cutting action.
Data Source
Figure 1
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Figure 3a~4
AI summary
The present invention is directed to a helical drill configuration that allows substantially flat bottomed holes to be machined. At the cutting end of the body member, there are at least two cutting edges that are symmetrically oriented on opposing sides of the rotational axis of the drill. In an embodiment of the invention, first and second cutting edge portions form a continuous surface which provides strength and tool stability. The height of the second portions of each of the cutting edges remains relatively consistent along the horizontal for formation of a generally flat bottom hole. In the embodiment, a center point is defined by two sloped peak surfaces. A central straight chisel edge is formed by the intersection of the two sloped peak surfaces. The first cutting edge section extends from the chisel edge to the second cutting edge section. The first cutting edge section for both cutting edges is formed by symmetrically thinning the two peak surface. In the invention, stress at the center portion of the helical cutting tool is limited by the chisel edge and first sections of the cutting edge near the center portion having a balanced geometry. The balanced geometry of the helical drill also prevents the drill from wobbling and creating deviations in the hole being formed. The chisel edge may blend with a first curvilinear cutting edge and the first curvilinear cutting edge may also have a positive rake to promote cutting.