SMT Line Improvements for High Mix, Low Volume …

SMT Line Improvements for High Mix, Low Volume Electronics Manufacturing by

William Edward Swaim

A thesis submitted to the Graduate Faculty of Auburn University

in partial fulfillment of the requirements for the Degree of

Masters of Science Auburn, Alabama

August 6, 2011

Approved by John L. Evans, Chair, Technology Management Professor of Industrial and Systems Engineering

Chase Murray, Assistant Professor of Industrial and Systems Engineering Richard Sesek, Assistant Professor of Industrial and Systems Engineering

Abstract

This work covers two major projects aimed at increasing quality and efficiency on a high mix, low volume surface mount electronics production line. Specifically the installation of a ten zone reflow oven and an enhanced changeover method for SMT pick and place machines. A full description of these projects is presented along with rationales and background on their real world implementations. The transition from a five to ten zone reflow oven represents many opportunities for reflow soldering quality improvements. Specifics about the enhanced profiling abilities gained with the longer oven are explored and results from the oven installation are presented. To increase SMT line efficiency various changeover methods are discussed. The "hot swap" method, a somewhat new and unknown setup strategy, is explored in detail. Results from an implementation of the "hot swap" changeover method are discussed. Additional productive enhancements to the strategy are proposed.

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Acknowledgements This work would have not have been possible without the support and guidance provided by a few individuals. I would like to especially thank Dr. John Evans for providing me with this opportunity. I fully believe the opportunities he has given me over the past two years will affect me for a lifetime. I would also like to thank Tom Devall. Throughout this project he has provided me with great direction and assistance. I must also mention Dr. Richard Sesek and Dr. Chase Murray who have helped me when needed and given me continuous support. I also want to acknowledge the opportunity afford by CoachComm. Without their agreement, none of this work would have been possible. Lastly, I want to sincerely thank Namo Vijaykumar, without his aid and friendship this work would be far form complete.

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Table of Contents

Abstract ........................................................................................................................................... ii Acknowledgements........................................................................................................................ iii List of Figures ............................................................................................................................... vii Chapter 1: Introduction and CoachComm Background.................................................................. 1

1.1 The Business ......................................................................................................................... 1 1.2 Manufacturing....................................................................................................................... 1 Chapter 2: Literature Review.......................................................................................................... 4 2.1 Surface Mount Electronics.................................................................................................... 4

2.1.1 Component Placement ................................................................................................... 5 2.1.1.1 Gantry-Style Placement Machines.......................................................................... 9

2.1.2 Reflow Soldering ......................................................................................................... 11 2.1.2.1 Solder Pastes ......................................................................................................... 12 2.1.2.2 Preheat Phase ........................................................................................................ 17 2.1.2.3 Soak of Pre-Reflow Phase .................................................................................... 18 2.1.2.4 Reflow Phase ........................................................................................................ 21 iv

2.1.2.5 Cooling Phase ....................................................................................................... 22 2.1.2.6 Reflow Ovens........................................................................................................ 22 2.2 Single Minute Exchange of Die .......................................................................................... 25 2.3 SMED and Increasing Throughput in SMT Electronics Manufacturing ............................ 27 2.3.1 Popular Setup Strategies .............................................................................................. 29 2.3.1.1 Unique Setup......................................................................................................... 30 2.3.1.2 Group Setup .......................................................................................................... 31 2.3.1.3 Minimum setup ..................................................................................................... 32 2.3.1.4 Partial Setup .......................................................................................................... 32 2.3.1.5 Hybrid Setup ......................................................................................................... 33 2.3.1.6 Hot Swap Setup..................................................................................................... 34 Chapter 3: Installation of New Reflow Oven ............................................................................... 35 3.1 Previous Oven Setup........................................................................................................... 35 3.2 Performance Metrics and Measurement Systems ............................................................... 37 3.3 Baseline System Performance............................................................................................. 42 3.4 New Oven Setup and Target Lead-Free Profile.................................................................. 46 3.5 Results................................................................................................................................. 49 3.6 Discussion and Future Work............................................................................................... 53 Chapter 4: SMT Product Changeover Time Reduction ................................................................ 55 4.1 Current Product Changeover Method ................................................................................. 55

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