Saw Blade Tooth Projection for Chip Redirection and Wear Control
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Solution Overview
Problem
Prior art band saw blades used for cutting difficult-to-cut materials like tool steels and nickel-based alloys suffer from short blade life and uneven cuts due to aggressive tooth geometries leading to rapid wear and increased cutting forces.
Innovation Solution
The saw blade design features a cutting edge with teeth having a positive rake angle, a flat or non-curvilinear projection between the rake face and gullet, and a repeating set pattern with varying set magnitudes, which redirects chips efficiently and reduces heat generation, resulting in longer blade life and straighter cuts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If extreme rake angles are applied to traditional tooth/set geometries, then cutting performance is improved when the blade is new, but tool wear increases rapidly and teeth fracture in an uncontrolled manner
Solution Approach 1:
The patent applies different geometric features to different parts of the tooth structure. The rake face maintains a moderate angle while a specific portion (the projection) has a different orientation and geometry. This local differentiation allows the cutting edge to perform effectively while reducing stress concentration and heat generation that lead to tooth fracture.
Solution Approach 2:
The patent modifies the geometric parameters of the tooth by adding a projection with specific dimensions and angles. The projection has a leading surface inclined at a specific angle range (10°-45°) relative to the rake face, creating a gradient in geometric parameters that optimizes both cutting performance and durability.
2Ease of operation
If a full-contact radius feature is incorporated on the rake face to capture chips, then chip capture is improved, but cutting forces increase and heat generation increases leading to more rapid wear
Solution Approach 1:
The patent segments the chip capture function from the rake face by introducing a separate projection structure. The projection's leading surface provides chip guidance and capture, while the rake face maintains its primary cutting function with reduced contact area. This segmentation allows chip capture without the full-contact radius that causes increased cutting forces and heat.
Solution Approach 2:
The projection acts as an intermediary element between the rake face and the chip flow. It provides a controlled interface for chip capture and redirection, mediating the interaction between the cutting edge and chips to reduce direct full-contact friction and heat generation on the rake face.
Data Source
AI summary
A saw blade, such as a metal-cutting band saw blade, has a cutting edge including a plurality of teeth. A plurality of the teeth include a tip, a clearance surface located on one side of the tip, a rake face located on an opposite side of the tip relative to the clearance surface, a gullet, and a substantially flat, linear, or non-curvilinear projection formed between the rake face and the gullet and projecting outwardly relative to the rake face. The projection is inclined at an acute angle relative to a plane extending between the tips of consecutive unset teeth. The projection defines an inner end adjacent to the rake face and an outer end adjacent to the gullet. The inner end is located at a depth below the tip of at least about 25/1000 inch, and the distance between the inner end and the outer end of the projection in a direction substantially parallel to the plane extending between the tips of at least two teeth is less than about 65/1000 inch.