Drill Tool Asymmetric Inserts for Balanced Cutting
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Solution Overview
Problem
Existing drill tools face challenges in achieving a 50:50 ratio of effective cutting edge lengths for inner and outer square-shaped indexable inserts when drilling small diameter holes, leading to intensified vibrations and reduced processing performance due to imbalanced force transmission.
Innovation Solution
A drill tool design featuring chamfered inner and outer inserts with specific angle configurations and two-stepped cutting edges, ensuring a 50:50 ratio of effective cutting edge lengths while maintaining the strength and durability of square-shaped inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If square-shaped inserts are used to drill small diameter holes, then four cutting edges can be utilized, but the effective cutting edge length ratio between inner and outer inserts cannot be maintained at 50:50
Solution Approach 1:
The patent applies asymmetry by modifying the cutting edge geometry of inner and outer inserts differently. The inner insert has its cutting edge chamfered at the radially inward side, while the outer insert has its cutting edge chamfered at the radially outward side. This asymmetric modification allows each insert to have different effective cutting edge lengths while maintaining the 50:50 ratio, resolving the contradiction between using square-shaped inserts and achieving the desired length ratio.
2Length of moving object
If the insert size is reduced to enable drilling of small diameter holes, then the drill can process smaller holes, but the insert strength is weakened
Solution Approach 1:
The patent applies local quality by selectively chamfering different portions of the cutting edges on inner and outer inserts. The inner insert is chamfered at the radially inward side while the outer insert is chamfered at the radially outward side. This localized modification optimizes the effective cutting edge length distribution without requiring a complete redesign of the insert geometry, thereby maintaining insert strength while enabling small diameter hole drilling.
3Ease of manufacture
If the effective cutting edge length ratio deviates from 50:50, then the drill can be simpler to manufacture, but vibrations are intensified and processing performance deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the chamfer angles and positions of the cutting edges on the inserts. By carefully controlling these geometric parameters, the effective cutting edge lengths are adjusted to achieve the 50:50 ratio. This parameter optimization reduces vibrations and improves processing performance while maintaining a relatively simple insert configuration that is easy to manufacture.
Data Source
AI summary
A drill tool including a drill body having an inner insert and an outer insert at an end portion of the drill body. The distance from a central axis of the drill body to the outer insert is greater than the distance from the central axis to the inner insert. The cutting edges of the inner and outer inserts can be chamfered with the inner insert chambered at a radially inward portion and the outer insert chamfered at a radially outward portion. The inner insert and the outer insert can be mirror symmetric to one another. The inner insert and the outer insert are mounted to the drill body such that an effective cutting length of the inner insert equals an effective cutting length of the outer insert, the effective cutting lengths being measured in a direction perpendicular to the central axis.