Two-Margin Drill Layout for Hole Roundness Without Rigidity Loss
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Solution Overview
Problem
Existing drills face challenges in maintaining high rigidity while improving the roundness of holes, as excessive torque during drilling can lead to deteriorated roundness and reduced rigidity when trying to extend the distance between drill margins.
Innovation Solution
A drill design with a specific configuration including a flank face, thinning face, outer peripheral surface, and swarf discharging surface, where the outer peripheral surface features a first and second margin with back tapers of the same angle, and a distance between the front ends of these margins is optimized between 3 mm and 5 mm to balance torque and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between drill margins is extended to improve hole roundness, then hole roundness is improved, but drill rigidity deteriorates
Solution Approach 1:
The drill margin is divided into two separate margins (first margin and second margin) with a specific distance between them. This segmentation allows the first margin to engage the workpiece for stable drilling while the second margin provides guidance for hole roundness, resolving the contradiction between rigidity and precision by distributing functions across separated elements.
Solution Approach 2:
The invention introduces a dimensional parameter (distance between margins of 3-5 mm) that optimizes the balance between rigidity and roundness. By controlling the spatial relationship between the two margins along the axial direction, the design achieves both sufficient structural rigidity and improved hole roundness through dimensional optimization.
2Manufacturing precision
If the distance between drill margins is extended to improve hole roundness, then hole roundness is improved, but excessive torque is generated
Solution Approach 1:
By segmenting the margin into two parts with controlled spacing, the first margin handles the primary cutting and torque transmission while the second margin provides gentle guidance. This segmentation prevents excessive torque by distributing the mechanical interaction between the drill and workpiece across two separated contact points.
Solution Approach 2:
The invention optimizes the distance parameter between margins (3-5 mm) to achieve the right balance. This parameter control ensures that the margins are far enough to reduce torque and improve roundness, but not so far as to compromise drill stability or generate excessive forces.
3Strength
If the distance between drill margins is reduced to maintain rigidity, then drill rigidity is maintained, but hole roundness deteriorates
Solution Approach 1:
The segmented margin design with 3-5 mm spacing proves that segmentation can simultaneously maintain rigidity (through the first margin's engagement) and improve roundness (through the second margin's guidance), contradicting the assumption that closer margins are needed for rigidity.
Solution Approach 2:
By changing the margin distance parameter to 3-5 mm, the invention achieves optimal performance where both rigidity and roundness are satisfied, demonstrating that the specific parameter range resolves the apparent contradiction between strength and precision.
4Force
If the distance between drill margins is reduced to control torque, then torque is controlled, but hole roundness deteriorates
Solution Approach 1:
The two-margin segmentation with 3-5 mm spacing demonstrates that proper segmentation can control torque (through distributed contact) while simultaneously improving roundness (through the second margin's guidance function), resolving the contradiction between force control and precision.
Solution Approach 2:
Optimizing the margin distance to 3-5 mm achieves the ideal balance where torque is adequately controlled and hole roundness is significantly improved, showing that parameter optimization resolves the trade-off between force management and manufacturing precision.
Data Source
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AI summary
A drill rotatable about an axial line has a flank face, a thinning face, an outer peripheral surface, and a swarf discharging surface. The thinning face is contiguous to the flank face. The outer peripheral surface is contiguous to each of the flank face and the thinning face. The swarf discharging surface is contiguous to each of the flank face and the outer peripheral surface. A ridgeline between the flank face and the swarf discharging surface forms a cutting edge. The outer peripheral surface is provided with a first margin contiguous to each of the cutting edge and the flank face, and a second margin that is located on the rear side with respect to the first margin in a rotation direction and that is separated from each of the flank face and the thinning face. An outer peripheral portion of the first margin and an outer peripheral portion of the second margin have respective back tapers having the same angle. In a direction parallel to the axial line, a distance between a front end of the first margin and a front end of the second margin is more than or equal to 3 mm and less than or equal to 5 mm.