EWMA Process Control for Cyclic Fluctuations in Electronics Manufacturing
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Solution Overview
Problem
Existing manufacturing systems struggle to effectively manage data values with trending cyclic fluctuations in process parameters, leading to the production of electronic devices with abnormal specifications.
Innovation Solution
A manufacturing system that includes a calculation unit to determine upper and lower control limit values based on previous data strings and an exponentially weighted moving average (EWMA) slope value, comparing these with real-time data to generate a comparison result.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed control limit values are used to monitor process parameters, then the manufacturing system can detect abnormal specifications, but the system cannot effectively control data values with trending cyclic fluctuations
Solution Approach 1:
The patent applies dynamics by transitioning from static fixed control limits to dynamic adaptive control limits. The control limits are continuously updated based on historical data and EWMA calculations, allowing the system to adapt to cyclic fluctuations in process parameters while maintaining reliable detection of abnormal specifications.
Solution Approach 2:
The patent changes the parameter of control limits from fixed values to dynamically adjusted values based on EWMA statistics. By modifying how control limits are calculated and updated over time, the system becomes capable of handling cyclic fluctuations while preserving its ability to detect abnormalities.
2Productivity
If the manufacturing system monitors process parameters in real-time, then it can generate warning messages for abnormal specifications, but it produces electronic devices with abnormal specifications when parameters show trending cyclic fluctuations
Solution Approach 1:
The patent implements feedback by using historical process data to continuously update control limits through EWMA calculations. This feedback mechanism allows the system to learn from past performance and adjust control parameters accordingly, improving specification compliance while maintaining real-time monitoring productivity.
Solution Approach 2:
The patent applies preliminary action by establishing adaptive control limits based on historical data before actual production occurs. This preparatory configuration enables the system to anticipate and prevent cyclic fluctuation issues before they result in defective products, while maintaining efficient real-time monitoring.
3Ease of operation
If conventional control methods are applied to process parameters, then the system operates efficiently, but the control limit values become inapplicable when data values show trending cyclic fluctuations
Solution Approach 1:
The patent achieves universality by creating a control system that handles both stable and cyclic fluctuating processes through a unified EWMA-based approach. This multi-functional control mechanism maintains ease of operation while ensuring reliability across different process conditions, eliminating the need for separate control strategies.
Data Source
AI summary
A manufacturing system for an electronic device is provided. The manufacturing system includes a manufacturing equipment, a calculation unit, and a comparison unit. The manufacturing equipment provides a previous data string and a real-time data string. The calculation unit receives the previous data string and outputs an upper control limit value and a lower control limit value accordingly. The comparison unit generates an exponentially weighted moving average (EWMA) slope value based on the real-time data string, and compares the EWMA slope value with the upper control limit value and the lower control limit value to generate a comparison result.