Asymmetric Step Drill Geometry for Low-Resonance Chip Removal
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Solution Overview
Problem
Existing multi-tip drilling parts experience resonance issues due to symmetrical cutting edges, leading to high cutting resistance and inefficient chip discharge, particularly in small step segments.
Innovation Solution
The drilling part features asymmetrical step segments with non-symmetrical cutting-edge tips, allowing for offset cutting and a composite cutting effect, distributing cutting force unevenly to prevent resonance and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If symmetrical cutting edges are used in multi-tip drilling part, then manufacturing precision and balance are improved, but cutting resistance increases and resonance occurs
Solution Approach 1:
The patent applies asymmetry by designing step segments where cutting edges on different sides have different radial distances from the working rotational axis. Specifically, at least one step segment has asymmetric configuration where the radial distance of cutting edges on one side differs from the radial distance of cutting edges on the other side, breaking the symmetry that causes resonance while maintaining cutting precision
Solution Approach 2:
The patent implements local quality by making different step segments have different asymmetry characteristics. Each step segment can have its own specific radial distance configuration, allowing localized optimization of cutting properties at different depths while maintaining overall drilling precision
2Productivity
If symmetrical cutting edges cut at the same time, then productivity is improved, but resonance and cutting resistance increase
Solution Approach 1:
The asymmetric step segment design causes cutting edges to operate at different radial positions, which disrupts the synchronous cutting action that generates resonance. The asymmetry allows multiple cutting edges to work simultaneously at different effective radii, maintaining productivity while eliminating the harmonic resonance caused by symmetrical simultaneous cutting
Solution Approach 2:
The patent changes the critical parameter of radial distance from uniform (symmetrical) to variable (asymmetrical). By making the radial distance of cutting edges different on opposite sides of the working rotational axis, the cutting timing and force distribution are altered, preventing resonance while maintaining efficient material removal
3Manufacturing precision
If small step segments are used, then manufacturing precision is improved, but chip discharge becomes difficult
Solution Approach 1:
The asymmetric design of step segments creates varied radial distances for cutting edges, which influences chip formation and discharge paths. This asymmetry helps prevent chip jamming in small step segments by creating more favorable chip flow conditions while preserving the precision cutting capability of the small diameter segments
Data Source
Figure 1a~2b
Figure 3a~4
Figure 5~6
AI summary
The present invention relates to a drilling part (4) for a hole processing tool, characterized in that the drilling part (4) comprises at least two chip-discharging flutes (3); a plurality of sides, each side comprising a plurality of step segment portions (Tn), the step segment portions of the same serial number or all sides form a single step segment, each side further comprising a transition segment portion (12); a plurality of major cutting edges; a plurality of minor cutting edges; and a plurality of cutting-edge tips (9), wherein at least one step segment is formed as an asymmetric step segment, and a single asymmetric step segment having at least two asymmetric step segment portions separated by a chip-discharging flute in a circumferential direction, the at least two asymmetrical step segment portions and at least two chip-discharging flutes forming correspondingly at least two asymmetrical cutting-edge tips, the at least two asymmetrical cutting-edge tips having different radial distances from a working rotational axis and being axially offset relative to each other in the direction of the working rotational axis. The present invention further relates to a hole processing tool.