Outlier Screening for Manufacturing Quality Control

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Solution Overview

Problem

Current quality control methods in manufacturing are resource-intensive and costly due to the need for extensive data analysis and testing of numerous parameters, which can be streamlined to reduce the number of measurements required for screening manufactured units.

Innovation Solution

The method involves measuring multiple parameters on manufactured units until failures occur, normalizing pre-failure data to identify outlier parameters, and using these parameters to screen subsequent units, thereby reducing the number of measurements needed for quality control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple parameters are measured and analyzed for each manufactured unit, then quality control reliability is improved, but testing costs and time consumption increase significantly

Engineering Contradiction:

Improvequality control reliabilityVSAvoidtesting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the quality control process into two phases: (1) an initial phase where multiple parameters are measured on units until failures occur to identify critical parameters, and (2) a subsequent phase where only those identified critical parameters are measured on all units. This segmentation reduces the measurement burden from measuring all parameters on all units to measuring only critical parameters on subsequent units.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by measuring multiple parameters and analyzing failure data before mass production screening. The pre-failure data analysis identifies which parameters are most indicative of defects, allowing the screening process to be optimized beforehand. This preliminary parameter identification phase enables more efficient subsequent screening.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple parameters are measured and analyzed for each manufactured unit, then quality control reliability is improved, but testing costs increase significantly

Engineering Contradiction:

Improvequality control reliabilityVSAvoidtesting costs

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by measuring only the critical parameters identified from failure analysis on subsequent units, rather than measuring all parameters. This partial measurement approach is sufficient for quality control purposes and significantly reduces testing costs while maintaining reliability.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If vast amounts of data are generated and analyzed, then measurement precision is improved, but resource consumption increases

Engineering Contradiction:

Improveparameter measurement precisionVSAvoiddata processing resources

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the critical parameters that are most indicative of failures from the full set of measured parameters. By analyzing pre-failure data and identifying which parameters show the strongest correlation with defects, the method extracts a small subset of critical parameters for ongoing screening, eliminating the need to process vast amounts of data from all parameters.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a simplified model or copy of the full measurement process by using only the critical parameters identified from initial failure analysis. This copied screening process uses a small subset of parameters rather than the complete parameter set, reducing data processing requirements while maintaining quality control effectiveness.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS7359813B2Outlier screening technique

Publication Date: 2008.04.15 TEXAS INSTRUMENTS INC

AI summary

Multiple parameters of manufactured units are continually measured until some of the units fail, where failure can be accelerated by adjusting operating conditions. Pre-failure data is then examined to find outliers or aberrant parameter values that may have contributed to the failures. The data is normalized to allow different parameters to be compared to one another. The parameters producing the highest outlier values are then used to screen subsequently manufactured units, thus significantly reducing the number of measurements that have to be taken to screen the units. Lower outlier values for these parameters are, however, used in screening subsequently manufactured units to “catch” potentially defective units.