Wire Saw Bearing Control for Flat, Parallel Slice Separation
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Solution Overview
Problem
Existing methods for cutting multiple slices using a wire saw struggle to achieve high plane parallelism and flatness, especially in the semiconductor industry, due to limited effectiveness of existing temperature control and correction methods.
Innovation Solution
A method that uses a wire saw with a tensioned wire array between two wire guide rollers, supported by fixed and floating bearings. The method involves adjusting the temperature of the fixed bearings with a cooling fluid according to a first temperature profile and simultaneously moving the floating bearings to correct shape deviations, while also controlling the workpiece temperature to minimize shape deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the position of wire guide roller is kept fixed, then the structure is simple, but shape deviations occur due to thermal expansion during cutting
Solution Approach 1:
The wire guide roller support structure is segmented into two independent bearing units: a fixed bearing that remains stationary and a floating bearing that can move axially. This segmentation allows different parts of the support system to perform different functions - the fixed bearing provides stable mounting while the floating bearing compensates for thermal effects
Solution Approach 2:
The floating bearing is designed to move dynamically in the axial direction of the wire guide roller during operation. This dynamic capability allows the bearing to automatically adjust its position in response to thermal expansion, maintaining proper wire tension and alignment without requiring complex active control systems
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
The method achieves slices with a target shape match as closely as possible by combining temperature-controlled wire guide rollers and workpiece movement, thereby improving the flatness and plane parallelism of slices.
Implementation Method 1
adjusting a temperature of the fixed bearings with a cooling fluid
Implementation Method 2
a thermal length increase or length decrease in the wire guide roller is brought about by adjusting the temperature of the wire guide roller interior
Implementation Method 3
material is removed by means of a three-body interaction involving the tool carrier (saw wire), the tool (abrasive) and the workpiece
Data Source
AI summary
Slices are cut from workpieces during a sequence of cut-off operations by a wire saw, having a wire array. The wire array is tensioned in a plane between two wire guide rollers supported between fixed and floating bearings. During each cut-off operation, a workpiece is fed through the wire array perpendicular to a workpiece axis and the wire array plane. The workpiece is fed with simultaneous axial movement of the floating bearings by adjusting a temperature of the fixed bearings in correlation with a first correction profile, which specifies a travel of the floating bearings in dependence on the depth of cut. In dependence on the depth of cut, operating parameters are set, such as the feed rate, an amount of working fluid fed to the wire array per unit time, a temperature of the working fluid, a wire speed, a wire consumption per cut-off operation, or a wire tension.