Carbide-Tooth Saw Blade Using Ductile Weld Zones for Fine Pitch Setting
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Solution Overview
Problem
Existing saw blades with fine pitch and hard metal cutting teeth face challenges in attaching and setting carbide inserts due to their small size, leading to manufacturing difficulties and potential fracturing.
Innovation Solution
The saw blade design incorporates hard metal strips with full carbide teeth that are set left or right by bending ductile weld fusion zones, allowing for easier attachment and setting without risking fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hard metal cutting inserts or tips are attached to a fine pitch saw blade, then cutting performance on hard materials is improved, but the small size of the teeth makes welding or brazing impractical and increases risk of fracturing
Solution Approach 1:
The hard metal cutting edge is divided into multiple separate carbide segments, each with its own base portion, rather than using a single continuous strip. This segmentation allows each segment to be independently attached to the blade body, making the attachment process more manageable and reducing the risk of fracturing during manufacturing.
Solution Approach 2:
A ductile weld fusion zone is introduced as an intermediary between the carbide segment and the blade body. This intermediate layer absorbs stress and prevents direct stress transfer to the brittle carbide, eliminating the need for complex attachment processes while preventing fracturing.
2Productivity
If carbide strips are set left or right to improve cutting performance, then kerf width and cutting efficiency are improved, but the high hardness and poor fracture toughness of carbide causes teeth to fracture during setting
Solution Approach 1:
The ductile weld fusion zone is created beforehand during the attachment process, serving as a cushioning layer that will absorb setting stresses before they reach the carbide teeth. This pre-established protective layer prevents fracturing during the subsequent setting operation.
Solution Approach 2:
The material properties at the interface are changed by creating a ductile weld fusion zone with different mechanical properties than either the carbide or the blade body. This parameter change in the intermediate layer allows it to deform plastically during setting, protecting the brittle carbide teeth from fracturing.
3Area of stationary object
If long carbide strips with many teeth are used, then coverage of the cutting edge is improved, but setting teeth in different directions causes fracturing of the carbide strip
Solution Approach 1:
The long carbide cutting edge is divided into multiple separate segments rather than using a single continuous strip. Each segment can be independently attached and set without affecting adjacent segments, eliminating the fracturing problem that occurs when trying to set a continuous long strip in different directions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables the production of saw blades with significantly longer life and improved cutting performance, even at fine pitches, while allowing for the blending of carbide grades for versatility in cutting various materials.
Implementation Method 1
bending ductile weld fusion zones
Data Source
AI summary
A saw blade includes an elongated body with a working edge extending along a longitudinal axis. A first strip composed of carbide or cermet and including at least one first full cutting tooth is coupled to a first portion of the working edge by a first weld fusion zone composed of a ductile material. The first strip is set in a first direction at a first angle out of a plane of the body by a first bend in the first weld fusion zone. A second strip composed of carbide or cermet and including at least one second full cutting tooth is coupled to a second portion of the working edge by a second weld fusion zone composed of a ductile material. The second strip is set in a second direction, opposite the first direction, at a second angle out of the plane of the body by a second bend in the second weld fusion zone.