Circular Saw Blade Gullet Geometry for Downward Chip Direction

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Solution Overview

Problem

Circular saw blades with tipped ends experience significant chip scattering rightward and leftward during cutting of synthetic resin or aluminum alloy materials, leading to noise and residual chips within hollow work pieces, which complicates post-processing and can cause issues with paint application and precision work.

Innovation Solution

The circular saw blade design features gullets with linearly extended gullet bottoms and back portions, along with a specific slant angle range, and an optional hollow face on the rake face of the tips, which directs chips to fall intensively below the rotation direction, reducing scattering and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If tips with one-side or both-side beveling are used to reduce cutting noise, then noise is significantly lowered, but chip scattering rightward and leftward increases

Engineering Contradiction:
Improvecutting noiseVSAvoidchip scattering
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The invention changes the geometric parameters of the tip by introducing a hollow face on the rake face, creating a cavity with specific depth and width relative to the tip width. This parameter modification redirects chip flow downward while preserving the noise-reducing beveling configuration, thereby resolving the contradiction between noise reduction and chip scattering control

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If alternating one-side and both-side beveled tips are used, then cutting noise is reduced, but residual chips remain inside hollow work pieces

Engineering Contradiction:
Improvecutting noiseVSAvoidresidual chip contamination
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The hollow face geometry parameters (depth H and width W relative to tip width) are optimized to maximize downward chip direction while maintaining compatibility with alternating beveling patterns. This ensures that chips are consistently directed downward regardless of tip type, preventing residual chip accumulation in hollow work pieces

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional tipped saw blade design is used, then cutting capability is maintained, but chip scattering rightward and leftward reaches up to 99%

Engineering Contradiction:
Improvecutting capabilityVSAvoidchip scattering
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The hollow face is introduced as a localized feature on the rake face of each tip, concentrating chip redirection functionality at the chip-formation zone. This local modification maintains the overall tip strength and cutting capability while effectively suppressing chip scattering through the cavity-induced flow redirection

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3090824B1Circular saw blade and method of working with circular saw blade
Publication Date: 2021.11.17 KANEFUSA HAMONO KOUGIYOU KK
  • EP3090824B1 patent drawingFigure 1A~1B
  • EP3090824B1 patent drawingFigure 2
  • EP3090824B1 patent drawingFigure 3A~3C

AI summary

A circular saw blade having tips (16) bonded to a base metal (12), rearward in a rotation direction of gullets (14), recessed in a periphery of the base metal (12) at predetermined intervals, wherein a gullet bottom (18) of the gullet (14) is linearly shaped, and a back portion (20) of the gullet (14) facing a rake face (22) of the tip (16) is linearly shaped, a slant angled formed by the back portion (20) with respect to a straight line (L1) passing a rotation center of the circular saw blade and a front portion (24) of the gullet bottom (18) in the rotation direction is between -5° and 35°, whereby: - either a slant angle formed by the linear gullet bottom (18) with respect to a straight line (L2) passing the rotation center of the circular saw blade and a rear portion (26) of the gullet bottom (18) in the rotation direction is between 45° and 100°, and a straight length (D) of the gullet bottom (18) is between 3.5 mm and 7.5 mm, - or the rake face (22) of the tip (16) in the gullet (14) and the back portion (20) facing the rake face (22) are set substantially in parallel to each other, and a slant angle formed by the linear gullet bottom (18) with respect to a straight line (L2) passing the rotation center of the circular saw blade and a rear portion (26) of the gullet bottom (18) in the rotation direction is between 45° and 60°.