Grinding Apparatus Sub-Chuck Table Height Measurement
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Solution Overview
Problem
The existing grinding apparatus struggles to measure the thickness of workpieces with large thicknesses and is affected by dirt on the holding surface, which hinders accurate measurement and wear calculation of grinding stones.
Innovation Solution
A grinding apparatus with a chuck table, grinding unit, and measuring units that include a sub-chuck table and a measuring unit moving mechanism to calculate workpiece thickness by measuring differences between the holding surface, sub-chuck table, and workpiece surface, while also calculating wear by storing and adjusting for grinding stone heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the upper surface height measuring gage is used to measure the height of the upper surface of the workpiece, then the thickness of the workpiece can be calculated, but the measurement cannot be performed when the workpiece has a large thickness
Solution Approach 1:
A sub-chuck table is introduced as an intermediary reference surface between the chuck table and the workpiece. The holding surface height measuring gage measures the height of the sub-chuck table upper surface, which serves as a reference plane. This intermediary allows the system to handle thick workpieces by providing a measurable reference point that the measuring gage can access, even when the workpiece thickness exceeds the direct measurement capability.
2Measurement precision
If the holding surface height measuring gage measures the height of the holding surface directly, then the thickness calculation can be performed, but the measurement is affected by dirt on the holding surface
Solution Approach 1:
The sub-chuck table acts as an intermediary reference surface that replaces the dirty holding surface as the measurement reference. By measuring the height of the sub-chuck table upper surface instead of the holding surface directly, the system eliminates the harmful effect of dirt contamination on measurement accuracy while maintaining the ability to calculate workpiece thickness.
3Device complexity
If the measuring units are fixed in position, then the structure is simple, but the measuring units cannot accommodate different workpiece thicknesses and measurement requirements
Solution Approach 1:
The base on which the holding surface height measuring gage and upper surface height measuring gage are mounted is made movable in the vertical direction by a measuring unit moving mechanism. This dynamic capability allows the measuring units to adjust their positions to accommodate workpieces of different thicknesses and to access the sub-chuck table reference surface, thereby increasing versatility without significantly complicating the overall structure.
Data Source
AI summary
A height of an upper surface of a sub-chuck table is measured by a holding surface measuring unit in contact with the upper surface of the sub-chuck table. A height of a holding surface of a chuck table is measured by an upper surface height measuring unit in contact with the holding surface of the chuck table. A first difference between the height of the upper surface of the sub-chuck table and the height of the holding surface of the chuck table is calculated. A workpiece is held on the holding surface, and the height of the upper surface of the sub-chuck table is calculated again by the holding surface measuring unit. The upper surface height measuring unit is brought into contact with the upper surface of the workpiece by vertically moving it, and the height of the upper surface of the workpiece is measured.