Drill Margin Extremity Burnishing for Ductile Material Finish
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Solution Overview
Problem
Drilling ductile materials like low carbon steel and alloy steel often results in poor finish quality, and existing drill designs tend to shatter during compression, limiting their longevity.
Innovation Solution
A drill or drill head design featuring a central axis with cutting portions that include a rake surface, relief surface, and a cutting edge, where the margin extends rearwardly from the relief surface and has an extremity outside the cutting diameter, providing a burnishing function and increasing tool longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a drill is designed with conventional geometry for drilling ductile materials, then it can maintain structural integrity, but it produces poor finish quality and the drill shatters during compression
Solution Approach 1:
The drill margin is segmented into multiple functional zones: a burnishing zone with the margin extremity outside the cutting diameter for finish quality, and a support zone within the cutting diameter for structural integrity. This segmentation allows each zone to perform its specific function without compromising the other.
Solution Approach 2:
Different portions of the margin are given different geometries and functions. The margin extremity (local region outside cutting diameter) provides burnishing action for high finish quality, while the margin portion within the cutting diameter provides structural support to prevent shattering. Each local region has optimized properties for its specific function.
2Manufacturing precision
If the margin extremity is positioned outside the cutting diameter to provide burnishing function, then finish quality improves, but the drill was expected to shatter under compression
Solution Approach 1:
The burnishing action is performed preliminarily during the drilling process itself, as the margin extremity continuously contacts and burnishes the hole surface during rotation and feed. This eliminates the need for separate finishing operations and ensures high surface quality is achieved during the primary machining operation.
Solution Approach 2:
The margin structure provides beforehand cushioning by distributing compressive forces through its geometry. The margin acts as a cushioning element that absorbs and distributes compression loads, preventing stress concentration that would lead to shattering, while still allowing the extremity to extend outside the cutting diameter for burnishing.
3Duration of action of stationary object
If the margin extends rearwardly from the relief surface with the extremity outside the cutting diameter, then tool longevity increases, but the geometry becomes more complex
Solution Approach 1:
The margin structure serves multiple functions simultaneously: it provides structural support within the cutting diameter, performs burnishing with the extremity outside the cutting diameter, and distributes compression loads. This multi-functionality increases tool longevity without requiring additional separate components, as the single margin structure accomplishes all these tasks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances drill longevity and maintains performance when drilling ductile materials by preventing shattering and improving finish quality, with specific protrusion distances and shapes optimizing performance across various cutting diameters.
Implementation Method 1
The margin, and more particularly the margin extremity, has been found to provide a burnishing function
Data Source
AI summary
A drill configured for drilling ductile materials includes a drill margin with a margin extremity adjacent to a relief surface. The drill includes a drill body and a drill head secured to the drill body via rotational coupling of the drill head on the drill body.