Wire Saw Roller Mount Geometry for High-Speed Wafer Cutting
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Solution Overview
Problem
Existing wire saws face limitations in achieving high wafer quality and throughput due to restricted rotational frequencies of wire guide rollers, which increase cutting time and reduce output, while also having a costly and space-consuming design.
Innovation Solution
The wire saw design features a larger distance between roller engaging portions and smaller inner diameter bearings, allowing for higher rotational speeds and flexibility in the holding members to adapt to tension forces, enabling increased wafer cutting efficiency and throughput while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large-diameter bearings are used to firmly hold holding members, then reliability of roller support is improved, but rotational frequency is limited due to increased friction losses and temperature
Solution Approach 1:
The patent changes the geometric parameters of the bearing system by increasing the distance F between roller engaging portions relative to the bearing inner diameter D (ratio F/D ≥ 6). This parameter change allows using smaller inner diameter bearings that generate less friction and heat, enabling higher rotational frequencies while maintaining adequate support reliability through the optimized geometric configuration.
2Manufacturing precision
If wire guide roller is kept short to make it stiff, then manufacturing precision is improved, but productivity decreases due to reduced throughput
Solution Approach 1:
The patent applies dynamics by allowing the wire guide roller to be flexible rather than rigid. The roller is designed with sufficient flexibility to adapt to tension forces from the cutting wire web, and the holding members can tilt according to a common bending line. This dynamic adaptation maintains wafer quality while enabling longer roller configurations that increase throughput.
Solution Approach 2:
The patent changes the geometric parameter F (distance between roller engaging portions) to be at least 6 times larger than the bearing inner diameter D. This parameter change enables the use of longer wire guide rollers that increase throughput while the optimized bearing configuration maintains the necessary stiffness and precision for high-quality cutting.
3Device complexity
If holding members are made compact with small bearings, then device complexity and space are reduced, but ability to adapt to tension forces is worsened
Solution Approach 1:
The patent makes the compact holding member design dynamic by allowing the holding members to tilt and adapt to tension forces. The smaller bearings enable this tilting motion more easily, and the holding members are designed to rotate and tilt according to a common bending line, providing adaptability to force variations while maintaining a compact configuration.
Solution Approach 2:
The patent segments the force adaptation function into two parts: the smaller bearings handle rotational support with reduced friction, while the holding members themselves provide force adaptation through tilting and rotation. This segmentation allows compact bearing design while maintaining adaptability through the holding member geometry and motion capabilities.
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 enhances wafer quality by allowing higher rotational speeds, reduces cutting time, and increases the number of wafers that can be cut, while also providing a cost-effective and space-efficient solution.
Implementation Method 1
the rolling elements of the bearing (e.g. cylindrical or ball shaped elements) have a larger contact area with the bearing rings so that they deform less
Implementation Method 2
at least one of the at least two bearings is an axial bearing, preferably a ball bearing
Data Source
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AI summary
The invention relates to a wafer cutting wire saw (1) comprising at least two roller mounts (20, 30), wherein at least one roller mount (20, 30) comprises at least - a first rotatable holding member (5) having a first shaft portion (7) and a first roller engaging portion (25) for engaging the wire guiding roller (2, 3) from a first side wherein the roller engaging portions (25, 26) face each other and wherein the rotational axis of the first holding member (5) and the rotational axis of the second holding member (6) essentially coincide with each other, wherein each of the holding members (5, 6) is rotatably supported by means of at least one bearing (9, 10), which surrounds the shaft portion (7, 8) of the holding member (5, 6) and is accommodated within a bearing support (11, 12), wherein the distance between the first roller engaging portion (25) and the second roller engaging portion (26) is at least 6 times larger than the inner diameter (D) of the at least one bearing (9, 10) surrounding the shaft portion (7, 8) of the first holding member (5).