Static Pressure Carrier Guides for Double-End Surface Grinder
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Solution Overview
Problem
Conventional methods for grinding thin sheet-like workpieces, such as silicon wafers, face challenges in maintaining high precision due to external force influences and wear issues with support rollers, leading to reduced rotation accuracy and increased maintenance needs.
Innovation Solution
A double-end surface grinder employs static pressure carrier guides that support the carrier ring in a non-contact manner, using static pressure pads and fluid to reduce external forces and maintain precision, with adjustable and pivotally supported carrier guides to ensure stable rotation and prevent wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If support rollers are used to support the carrier ring in a contact manner, then the carrier ring can be supported structurally, but external forces are applied to the carrier ring causing runout and reduced rotation precision
Solution Approach 1:
The patent replaces the mechanical contact support system (support rollers) with a non-contact support system using static pressure pads and fluid pressure. This substitution eliminates the transmission of external forces and runout from the support mechanism to the carrier ring, thereby maintaining rotation precision while providing structural support.
Solution Approach 2:
The patent employs static pressure pads and fluid pressure to support the carrier ring in a non-contact manner. The fluid pressure creates a cushion that supports the carrier ring without physical contact, preventing the transmission of external forces and maintaining high rotation precision throughout the grinding operation.
2Reliability
If support rollers are used to support the carrier ring, then the carrier ring can be supported, but the support rollers are subject to wear and friction leading to reduced accuracy over time
Solution Approach 1:
The patent replaces the mechanical contact support system (support rollers subject to wear) with a non-contact support system using static pressure pads and fluid pressure. This substitution eliminates friction and wear between the support mechanism and the carrier ring, ensuring that rotation precision is maintained throughout the entire service life of the equipment without degradation.
Solution Approach 2:
The patent employs static pressure pads and fluid pressure to support the carrier ring without physical contact. This eliminates the friction and wear that would otherwise occur with contact-based support rollers, thereby extending the service life of the support system and maintaining consistent rotation accuracy over time.
3Device complexity
If a direct-contact support method is used, then the structure is simple, but the workpiece cannot be ground with high precision due to transmitted runout
Solution Approach 1:
The patent replaces the simple but imprecise direct-contact support structure with a non-contact support system using static pressure pads and fluid pressure. Although this increases device complexity, it eliminates the transmission of runout and external forces to the carrier ring, thereby enabling high-precision grinding of thin sheet-like workpieces.
4Reliability
If conventional contact support method is used, then the carrier ring can be supported by support rollers, but runouts of support rollers are transmitted and synthesized causing deterioration of rotation precision
Solution Approach 1:
The patent replaces the contact-based support roller system with a non-contact support system using static pressure pads and fluid pressure. This substitution prevents the transmission and synthesis of runouts from multiple support points, maintaining high rotation accuracy of the carrier ring throughout the grinding operation.
Solution Approach 2:
The patent employs static pressure pads and fluid pressure to support the carrier ring without physical contact. This eliminates the runout transmission that occurs with mechanical support rollers, as the fluid pressure support does not have rotational imperfections or manufacturing tolerances that would transmit error to the carrier ring.
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 enhances grinding precision and durability, reducing edge runout and maintaining high accuracy over time by minimizing friction and wear, while allowing for easy adjustment and maintenance.
Implementation Method 1
both surfaces of a thin sheet-like workpiece are ground by a pair of grinding wheels while rotating the workpiece via a carrier in a state where the workpiece is supported by static pressures of a pair of static pressure pads in a non-contact manner
Implementation Method 2
an outer peripheral surface of a carrier ring disposed on the outer periphery of the carrier and substantially concentrically with the rotation center of the carrier is supported by static pressures of a plurality of static pressure carrier guides in the circumferential direction in a non-contact manner
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
[Object] To reduce influences of external forces that are to be applied to a carrier ring and improve workpiece grinding precision, and maintain high grinding precision over a long period of time without problems such as wear, etc. [Solution Means] In a double-end surface grinder that grinds both surfaces of a thin sheet-like workpiece W by a pair of grinding wheels 3 while rotating the workpiece W via a carrier 4 in a state where the workpiece W fitted to the carrier 4 is supported by static pressures of a pair of static pressure pads 1 in a non-contact manner, a plurality of static pressure carrier guides 6a and 6b that support a carrier ring 5 on the outer periphery of the carrier 4 by static pressures in a non-contact manner are provided in the circumferential direction. The carrier ring 5 has a cylindrical outer peripheral surface 12, and in proximity to the outer peripheral surface 12, static pressure carrier guides 6a and 6b are disposed at substantially even intervals. The static pressure carrier guides 6a and 6b may be fixed or floatable.