Stepped Rotary Tool Helix Layout for Low Deflection Drilling
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Solution Overview
Problem
Stepped drills face challenges in balancing helix angles between small and large diameter portions to minimize cutting resistance and deflection, leading to issues with run-out and deflection during machining.
Innovation Solution
A rotary tool design featuring a body with distinct helix angles for different parts, where the second helix angle is smaller than the first, reducing cutting resistance and deflection while enhancing strength and chip dischargeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the helix angle of the small diameter portion is increased to reduce cutting resistance, then cutting resistance is reduced, but deflection of the large diameter portion becomes more significant
Solution Approach 1:
The patent applies different helix angles to different portions of the drill: a larger helix angle (30-45 degrees) for the small diameter portion to reduce cutting resistance, and a smaller helix angle (10-20 degrees) for the large diameter portion to reduce deflection. This local differentiation resolves the contradiction by optimizing each portion's helix angle according to its specific functional requirements.
2Strength
If the helix angle of the large diameter portion is reduced to reduce deflection, then deflection is reduced, but cutting resistance of the small diameter portion is increased
Solution Approach 1:
The patent applies different helix angles to different portions of the drill: a smaller helix angle (10-20 degrees) for the large diameter portion to reduce deflection, and a larger helix angle (30-45 degrees) for the small diameter portion to maintain low cutting resistance. This local differentiation resolves the contradiction by optimizing each portion's helix angle according to its specific functional requirements.
3Force
If the helix angles of both small and large diameter portions are increased to reduce cutting resistance, then cutting resistance is reduced, but deflection becomes more significant
Solution Approach 1:
The patent applies different helix angles to different portions of the drill: a larger helix angle (30-45 degrees) for the small diameter portion to reduce cutting resistance, and a smaller helix angle (10-20 degrees) for the large diameter portion to reduce deflection. This local differentiation resolves the contradiction by optimizing each portion's helix angle according to its specific functional requirements.
4Strength
If the helix angles of both small and large diameter portions are reduced to reduce deflection, then deflection is reduced, but cutting resistance is increased
Solution Approach 1:
The patent applies different helix angles to different portions of the drill: a smaller helix angle (10-20 degrees) for the large diameter portion to reduce deflection, and a larger helix angle (30-45 degrees) for the small diameter portion to maintain low cutting resistance. This local differentiation resolves the contradiction by optimizing each portion's helix angle according to its specific functional requirements.
Data Source
AI summary
A rotary tool according to a non-limiting aspect includes a body having a rotation axis and extending from a first end to a second end. The body including: a first part including the first end; a second part located closer to a second end than the first part and having a larger outside diameter than the first part; a cutting edge located at a side of the first end; a ridge portion located in the first part and the second part, connected to the cutting edge and helically extending from the cutting edge toward the second end; and a flute located along the ridge portion. The flute includes: a first flute located at the first part and having a first helix angle; and a second flute located at the second part and having a second helix angle. The second helix angle is smaller than the first helix angle.