A Systems Approach to Electronic Assembly Optimization L

A Systems Approach to Electronic Assembly Optimization L B Newnes, A R Mileham and A Doniavi Chris Egbert Dec. 8, 2008

Function To describe a generic systematic model for optimizing Electronics Manufacturing To put forth a method for improving an entire system rather than discrete subsystems Focus on the electronics assembly portion of electronics manufacturing

Importance “Electronics manufacturing comprises 1/3 of all manufacturing in the world!” – Dr. Red Increasing the rate of successfully made assemblies will reduce wasted resources and increase revenues Offer manufacturers a comprehensive and overall approach to achieve an optimal system and desired targets Create a model that may predict the behavior of an electronics assembly system

References 1 Brindley, K. Newnes Electronics Assembly Handbook, Techniques, Standards and Quality Assurance, 1990 (Heinemann Newnes, London). 2 Groover, M. P. Fundamentals of Modern Manufacturing, Material, Processes, and Systems, 1996 (Prentice-Hall, Englewood Cli. Vs, New Jersey). 3 Edwards, P. R. Manufacturing Technology in the Electronics Industry, 1991 (Chapman and Hall, London). 4 Conway, P. P. , Whalley, D. C. , Wilkinson, M. and Williams, D. J. Automated adaptive control of the re¯ow soldering of electronic assemblies. In Proceedings of the 21 st IEEE International Electronic Manufacturing Technology Symposium, Austin, Texas, October 1997, pp. 229± 236. 5 Doniavi, A. , Mileham, A. R. and Newnes, L. B. A systems approach to modelling in the manufacturing environment. In Twelfth National Conference on Manufacturing Research, Bath, September 1996. 6 Doniavi, A. , Mileham, A. R. and Newnes, L. B. Computer Doniavi, Mileham, Newnes, integrated systems engineering in an electronics manufacturing environment. In 13 th National Conference on Manufacturing Research, Glasgow, Scotland, September 1997. 7 Nookabadi, A. S. and. Middle, E. A generic IDEF 0 model of Nookabadi, and. Middle, quality assurance information systems for the design-toorder manufacturing environment. IEEE Trans. Components, Packag. , Mfg Technol. , April 1996, 19(2), 78± 84. Packag. , Technol. , 8 Wu, B. Manufacturing Systems Design and Analysis, 1994 (Chapman and Hall, London). 9 Field, S. W. and Swift, K. G. EVecting a Quality ChangeÐ An Engineering Approach, 1996 (Arnold, London). 10 Milton, J. S. and Arnold, J. C. Introduction to Probability and Statistics, Principles and Application for Engineering and the Computer Sciences, 1995 (Mc. Graw-Hill, New York). 11 Doniavi, A. Computer aided systems engineering approach Doniavi, to electronic manufacturing modelling. Ph. D thesis, University modelling. of Bath, January 1999.

Relation to Technical Area It is aimed to increase the yield of electronics manufacturing systems as a whole Focuses more specifically on the electronics assembly aspect of electronics manufacturing (as opposed to printed circuit board and semiconductor device manufacturing)

Parameters Defined Stage 1: Setting Objectives Stage 2: IDEFO Model Stage 4: Generic PCR charts Stage 10: Levels Aggregation of Overall System

Design Defined IDEF, integral computer aided manufacturing definition language PCh, process characteristics PCR, process capability ratio MOE, measurement operation evaluation FMECA, failure mode effect criticality analysis Steps 1, 2, 4, and 10 specifically focused on in paper

Design Defined (cont. ) The overall EM process was broken down into the IDEFO model of Fig 2 EA was then broken down to the IDEFO model of Fig 3 Each subsystem was then broken down into “more detailed models”

Design Principle Research performed at a company that manufactures switch meters IDEFO provided a means to examine the inputs, outputs, and interdependencies of each process n n Also allows an approach to obtaining various static models Generated process maps were useful in validating results of stage 1 with industry before proceeding to stage 2

Experimental Equipment IDEFO in software format SMC Onsertion Lead Component Insertion Soldering Flow/ Reflow Testing Packaging

Design Principle Application The height of soldering paste on the board is one aspect that must be controlled to certain specifications In order to determine whether the process was capable of meeting the specifications, a PCR analysis was performed using historical industrial data Cp can be used to quantify the ability of a process to meet the specification Where alpha = 0. 05 and n, the number of observations = 20, The confidence interval is found to be: 1. 24 <= Cp <= 2. 33 • Cpk is used to measure the realized process capability achieved in actual production and has the advantage over the Cp ratio in that it can be applied to both skewed and normal distributions Cpk confidence interval is: 0. 83 <= Cpk <= 1. 68

Data and Tables indicate that each sub-process has a significant impact of the overall yield Figure 5 shows the proportion of defects, with an average of 16% Results indicate a failure rate of 16%, which corresponds to industrial data

Correlation of Results with Model The lower confidence bound a Cpk value of 1. 25 was determined using L was found to be 0. 91, therefore the process is concluded to be not capable

Industrial Use Optimization of any aspect of Electronics Manufacturing n n Printed Circuit Boards Semiconductor Devices Electronics Assembly As well as all sub-processes Identification of processes responsible for defects

Technical Advancement Provides a model for predicting manufacturing yield Allows analysis of each sub-process, in order to identify limiting factors Uses statistical approach to give added confidence to calculated yield

Impacted Industries Switch Meters PLC’s Personal Electronics Computers Data Acquisition Systems Motherboards Virtually any electronic device industry (anything that needs to be plugged in)