Crimped Saw Wire Spool With Rotational Symmetry for Wafer Cutting
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Solution Overview
Problem
Structured saw wires used for cutting hard and brittle materials often experience uneven wear due to lack of circular symmetry, leading to increased total thickness variation and saw marks in wafers, and existing solutions for helicoidal shapes face efficiency obstacles in production.
Innovation Solution
A spool with saw wire featuring two or more crimp deformations perpendicular to the longitudinal axis, combined with elastic and/or plastic rotations per unit length, which maintains the wire's rotation around its axis during cutting, preventing preferential direction formation and enhancing abrasive transport and swarf evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If structured saw wires with crimps are used to improve abrasive transport and swarf evacuation, then cutting speed and productivity increase, but the wire develops a preferential direction due to lack of circular symmetry, leading to increased total thickness variation and saw marks
Solution Approach 1:
The patent applies asymmetry by introducing elastic and plastic rotations to the structured saw wire, creating a helical configuration that breaks the rectangular symmetry of conventional crimped wires. This rotational asymmetry ensures that the wire maintains circular symmetry in its action plane, preventing preferential direction formation while preserving the productivity benefits of structured wire design
Solution Approach 2:
The patent introduces dynamic elements by incorporating elastic rotations that allow the wire to adapt its configuration during operation. The elastic crimps can deform and rotate, enabling the wire to maintain optimal geometry for abrasive transport and swarf evacuation while preventing the development of fixed preferential directions that cause thickness variation
2Loss of substance
If the saw wire is made thinner to reduce material abrasion and increase wafer extraction, then more wafers can be produced from the same material block, but the wire cannot sustain sufficient working force to maintain tautness and exert downward pressure on the abrasive
Solution Approach 1:
The patent applies local quality by concentrating the structural modifications (crimps and rotations) at specific locations along the wire rather than uniformly thickening the entire wire. The thin wire diameter is maintained in the cutting zone where material removal occurs, while the crimped and rotated sections provide localized structural reinforcement to sustain working forces
Solution Approach 2:
The patent creates a composite structure by combining the thin steel wire base material with added geometric features (crimps and rotational deformations). This composite configuration allows the wire to maintain low overall material volume for reduced abrasion while the geometric composite structure provides the necessary mechanical strength and force transmission capability
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 configuration results in improved surface quality of cut wafers with reduced wear and increased throughput, as the rotary movement agitates slurry and prevents wire direction bias, leading to better wafer characteristics and reduced wire consumption.
Implementation Method 1
The saw wire has a number of elastic rotations per unit length that are applied in an elastic rotation direction
Implementation Method 2
the rotation of the crimp deformations is permanent along the longitudinal direction of the saw wire
Data Source
AI summary
A spool of saw wire is disclosed. The saw wire is wound on the core of the spool (718). The saw wire is made of steel wire (406) wherein two or more crimp deformations are implemented. Each of said two or more crimp deformations has a crimp direction that is perpendicular to the longitudinal axis. Each of the crimp directions is different from the other crimp directions. The saw wire on the spool comprises a number of elastic rotations per unit length applied in the elastic rotation direction. The spool with saw wire can give excellent processability in the sawing process.