Wire Saw Slurry Distribution for Silicon Ingots
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Solution Overview
Problem
Conventional methods for cutting large-diameter silicon ingots with wire saws face issues such as uneven abrasive grain slurry supply, leading to reduced cutting performance, wafer defects like undulation and breakage, and quality issues like cracking due to excessive slurry vibration.
Innovation Solution
A method involving the supply of a first abrasive grain slurry to two points on the saw wire separated by a predetermined distance, with a second slurry supplied to the meshing area, ensuring consistent slurry distribution and preventing unnecessary stress and heat during cutting, thereby maintaining precise cutting and preventing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abrasive grain slurry is supplied from nozzles on both sides of the workpiece onto the saw wire, then the saw wire is lubricated and cooled, but for large-diameter workpieces (450mm), the slurry supply becomes insufficient along the cutting run, causing decline in cutting performance
Solution Approach 1:
The patent segments the slurry supply system into multiple zones along the cutting run. Nozzles are positioned at different locations (entry side, intermediate position, exit side) to divide the long cutting path into segments, each with dedicated slurry supply points. This ensures adequate slurry coverage throughout the entire cutting run for large-diameter workpieces, preventing performance decline.
Solution Approach 2:
The patent introduces a longitudinal dimension to the slurry supply system by placing nozzles at multiple positions along the cutting run direction, not just at the entry and exit sides. This multi-point distribution along the length of the workpiece ensures consistent slurry supply throughout the cutting path, addressing the insufficient coverage problem in large-diameter cutting.
2Reliability
If the whole area where the saw wire and workpiece contact is immersed into abrasive grain slurry, then the cutting area is well-lubricated, but the saw wire vibrates in the cutting groove causing wafer cracking
Solution Approach 1:
The patent applies local quality by providing slurry supply at specific localized positions (entry side nozzle, intermediate nozzle, exit side nozzle) rather than immersing the entire cutting area. This targeted approach ensures adequate lubrication at critical zones while avoiding excessive slurry that would cause vibration and cracking in other areas.
Solution Approach 2:
The patent uses partial action by supplying slurry to specific segments of the cutting run rather than completely immersing the cutting area. The intermediate nozzle positioned at 1/3 to 2/3 of the cutting run provides slurry to the critical intermediate zone without excessive slurry in areas where it would cause vibration and cracking.
3Manufacturing precision
If excessive abrasive grain slurry is supplied to the cutting area, then the cutting surface is well-protected, but the slurry liquid vibrates violently causing sliced parts to vibrate and touch each other
Solution Approach 1:
The patent applies local quality by positioning nozzles at specific locations (entry side, intermediate, exit side) to provide slurry only where needed for lubrication and cooling. This prevents excessive slurry accumulation that would cause violent vibration, while still protecting the cut surface with adequate slurry supply at critical zones.
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 approach allows for precise cutting of large-diameter workpieces with improved cutting speed and surface quality, reducing defects and enhancing processing reliability.
Implementation Method 1
a slurry containing abrasive grains (hereinafter called 'abrasive grain slurry') is supplied to a saw wire and the workpiece then is cut
Data Source
AI summary
A method for cutting a workpiece with a wire saw includes running at least one saw wire in a lateral direction. A first abrasive grain slurry is supplied to the saw wire on two points that are separated by a predetermined distance in a lateral direction. Cutting of the workpiece is started by moving at least one of the workpiece and the saw wire relative to the other and bringing the workpiece into contact with the saw wire from above at a location between the two points on the saw wire where the first abrasive grain slurry is supplied. A second abrasive grain slurry is supplied to a part of an area where the saw wire meshes with the workpiece.