Upper Turn Table Eccentricity Detection in Polishing Apparatus

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Solution Overview

Problem

The existing double-side polishing and lapping apparatuses face issues with workpiece holding abnormalities, leading to damage during machining, which decreases yield rates, increases costs due to component replacement, and degrades machine accuracy over time, making it difficult to detect and correct deviations in the center of the cylinder and upper turn table alignment.

Innovation Solution

A machining apparatus equipped with an upper turn table support mechanism featuring a vertically movable cylinder, a horizontal plate with displacement sensors to measure height positions, and a control apparatus that calculates the relative height position and eccentric angle of the upper turn table, enabling real-time detection of workpiece holding abnormalities and apparatus deviations, thus preventing damage and maintaining quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual handling or automatic handling apparatus is used to insert workpiece into carrier, then workpiece can be held for machining, but workpiece holding abnormality occurs leading to damage

Engineering Contradiction:

Improveworkpiece insertion operationVSAvoidworkpiece holding accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary detection of workpiece holding state before machining begins. The detection apparatus checks whether the workpiece is correctly positioned in the carrier, and only allows machining to proceed when proper holding is confirmed, preventing damage from abnormal holding conditions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detection apparatus provides feedback on workpiece holding status to the control system. When abnormal holding is detected, the system generates an alarm and prevents machining, creating a closed-loop control that ensures reliable workpiece holding

Inventive Principle:

Principle #23Feedback

2Productivity

If polishing slurry is supplied to enable efficient polishing, then machining efficiency is improved, but workpiece protrusion damage occurs when workpiece is abnormally held

Engineering Contradiction:

Improvepolishing efficiencyVSAvoidworkpiece damage from protrusion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The detection apparatus performs preliminary checking of workpiece holding state before the polishing process begins. By detecting abnormal holding conditions in advance, the system prevents the supply of polishing slurry to improperly held workpieces, thereby preventing damage while maintaining efficient polishing when holding is correct

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the detection apparatus to control the polishing process. Polishing slurry supply and machining operations are conditioned on confirmed proper workpiece holding, creating a safety mechanism that eliminates damage risk without reducing productivity

Inventive Principle:

Principle #23Feedback

3Ease of operation

If upper turn table support mechanism with cylinder is used to move turn table up and down, then workpiece can be clamped between turn tables, but deviation of cylinder center from turn table rotational axis degrades machine accuracy

Engineering Contradiction:

Improveturn table positioningVSAvoidmachine accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The detection apparatus continuously monitors the relative position between the cylinder center and the turn table rotational axis during operation. When deviation exceeds acceptable thresholds, the system generates alarms and can adjust positioning, creating feedback control that maintains manufacturing precision while preserving operational ease

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system replaces purely mechanical alignment methods with sensor-based detection and electronic control. By using detection apparatus to monitor and control alignment, the system achieves higher precision without complicating the mechanical structure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10166649B2Machining apparatus for workpiece

Publication Date: 2019.01.01 SHIN ETSU HANDOTAI CO LTD

AI summary

A machining apparatus for a workpieces includes an upper turn table support mechanism supporting an upper turn table from above to be vertically movable by a cylinder extending along a rotational axis direction of the table, a horizontal plate fixed to the cylinder so that a main surface thereof becomes perpendicular to a longitudinal axis of the cylinder, at least three displacement sensors which measure horizontal plate surface height positions when the upper turn table has moved down to a fixed position, and a control apparatus to calculate a relative upper turn table height position and an angle formed between the upper turn table rotational axis and the cylinder longitudinal axis from the horizontal plate surface height positions measured by the displacement sensors. A workpiece holding abnormality can be accurately and quickly detected before machining the workpiece to avoid damage, and an cylinder eccentric angle can be detected during machining.