Four-Flute Drill Tip Structure for Biting and Chip Discharge
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Solution Overview
Problem
Conventional 4 flute drills face issues with insufficient biting property and poor chip discharge due to increased chisel edge thickness and narrower flute grooves, leading to reduced machining efficiency.
Innovation Solution
A cutting tool design featuring four or more cutting edges with a first tip portion forming a sharp first tip angle, a second tip portion with a larger second tip angle, a gradually decreasing first core thickness portion, and a constant second core thickness portion, along with a two-stage thinning portion to enhance biting and chip discharge properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of cutting edges is increased to four or more, then chip discharge property is improved, but the chisel edge becomes thicker and biting property deteriorates
Solution Approach 1:
The patent applies local quality by creating different tip angle regions: a first tip portion with a first tip angle and a second tip portion with a second tip angle that is larger than the first. This allows the first tip portion to provide sharp biting while the second tip portion provides structural support, resolving the contradiction between having multiple cutting edges for chip discharge and maintaining a sharp chisel edge for biting.
2Strength
If the chisel edge is made larger to ensure drill tip strength, then structural integrity is improved, but biting property deteriorates
Solution Approach 1:
The patent divides the tip structure into two distinct portions with different tip angles. The first tip portion has a smaller tip angle optimized for biting, while the second tip portion has a larger tip angle providing structural support. This local differentiation allows the drill tip to have both strength and biting capability simultaneously.
Solution Approach 2:
The patent segments the tip structure into functionally distinct first and second tip portions. This segmentation allows each portion to be optimized for its specific function - the first for cutting/biting and the second for structural support - thereby resolving the contradiction between strength and biting property.
Data Source
AI summary
Provided is a cutting tool capable of improving both the biting property to a work material and the chip discharge property. The cutting tool includes a drill body rotated about a central axis, four or more cutting edges formed on one end portion of the drill body to face a forward side of a rotation direction, and a flute groove that is formed between the cutting edges adjacent to each other in a circumferential direction and extends substantially spirally along the central axis. (1) The one end portion includes a first tip portion that includes the central axis and has a first tip angle, and a second tip portion that extends from the first tip portion to an outer peripheral edge of the drill body and has a second tip angle larger than the first tip angle, and (2) the drill body includes a first core thickness portion that is formed in such a manner that a core thickness thereof gradually decreases from the one end portion to the other end portion, and a second core thickness portion that is formed in such a manner that a core thickness thereof is constant from the first core thickness portion toward the other end portion.