Hole Saw Tooth Layout for Burning Control and Swarf Expulsion
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Solution Overview
Problem
Existing hole saws experience serious burning and wear during cutting, leading to a limited lifespan and difficulty in expelling swarf, especially when cutting through materials like wood and metal.
Innovation Solution
The hole saw features a unique cutting tooth configuration with a front cutting face comprising a planar part and an arched-surface part, where the planar part accounts for less than 20% of the tooth depth, facilitating swarf expulsion and reducing resistance, along with varying sub-tooth amounts and angles to distribute wear evenly among teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cutting teeth are distributed uniformly at the circumferential edge, then the hole saw can cut round holes, but the cutting teeth experience serious burning and wear
Solution Approach 1:
The cutting teeth are segmented into multiple functional types (inner sub-teeth offset towards axis, outer sub-teeth offset away from axis, and straight teeth) rather than uniform distribution. This segmentation allows different teeth to perform different functions: inner teeth remove material from the inner radius, outer teeth from the outer radius, and straight teeth from the middle, distributing wear more evenly and reducing burning
Solution Approach 2:
Different regions of the cutting edge are given different tooth configurations tailored to local requirements. Inner sub-teeth have offset towards the axis to handle inner radius material removal, outer sub-teeth offset away for outer radius, and straight teeth for intermediate zones. This local optimization reduces stress concentration and thermal buildup at any single location
2Strength
If the planar part of the front cutting face is long, then the cutting tooth is strong, but swarf expulsion becomes difficult and resistance increases
Solution Approach 1:
The geometry of the front cutting face is optimized by changing the parameters of its components: the planar part length S is limited to ≤20% of tooth depth H (preferably ≤15%), while the arched-surface part accounts for ≥80% of tooth depth. This parameter optimization maintains sufficient strength through the arched geometry while dramatically improving swarf expulsion by reducing the planar surface that swarf must slide across
Solution Approach 2:
The front cutting face incorporates a dominant arched-surface part (≥80% of tooth depth) instead of a long planar surface. This curved geometry reduces friction and resistance against swarf, allowing chips to be ejected more easily from the cutting zone, while still providing adequate structural strength through the arch shape
3Ease of manufacture
If cutting teeth have uniform configuration, then manufacturing is simple, but wear is not evenly distributed leading to premature failure
Solution Approach 1:
The cutting teeth are configured asymmetrically with respect to the cutting axis: inner sub-teeth are offset towards the axis, outer sub-teeth are offset away from the axis, and straight teeth remain unoffset. This asymmetric arrangement ensures that teeth at different radial positions experience more uniform wear patterns, as each tooth type is optimized for its specific location, preventing premature failure from uneven stress distribution
Data Source
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AI summary
The present application provides a hole saw, and a device for cutting a hole. The hole saw (100) according to the present application has an axis (A), the hole saw (100) comprising: a cylindrical body (120); and multiple cutting teeth (110) disposed at a circumferential edge of the body (120), the multiple cutting teeth (110) comprising: inner sub-teeth (1121, 1125) offset towards the axis (A), outer sub-teeth (1122, 1124) offset away from the axis (A), and straight teeth (1123, 1126) which are not offset, wherein for 80% or more of the multiple cutting teeth (110), the ratio of the tooth depth (H) of the cutting tooth to the pitch (P) of the cutting tooth and the preceding cutting tooth thereof is in the range of 30% - 60%.