Prediction of wave solder machine parameters based on printed circuit board design characteristics /
This thesis shows the prediction models developed using board
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1994.
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| Summary: | This thesis shows the prediction models developed using board design characteristics to predict key wave soldering process parameters. Circuit boards that are to be wave soldered go through four major steps: fluxing, preheating, soldering,, and cleaning. Establishing process settings for a new circuit board requires using several production boards and running the machine multiple times until there is a minimum of solder defects. The use of these predictive models will help reduce experimental testing on production circuit boards for optimizing machine settings in the soldering process. Models developed for the key wave soldering process parameters included conveyor speed and preheat temperature. The modeling research involved experimentation with several methods: multivariate regression, multiple linear regression, regression for matrix combination of both parameters, and thermal radiative equations. The model building data set used in the research has process data and design characteristics for about 200 board designs. The process data comes from developing optimized empirical machine settings on the tlectrovert's Ultra Pak 337 wave soldering machine at Westinghouse. The final model results started from 26 initial design variables identified by process engineers at Westinghouse. Conveyor speed modells design variables included: material (heatsink, laminate, B-Stage) thicknesses, laminate type, component population (total components) and volume (multi- hybrid packages, mechanical parts, axial components) per bareboard area, and mass per bareboar d area of the circuit board. The preheat temperature model variables are: conveyor speed, bareboard thickness, lead population per bareboard area, component (mechanical and connector) volume per bareboard area,, weight per bareboard area and density of the circuit card. The preheat model includes conveyor speed to account for the rate of heat absorption as the board passes through the preheat zone. The models were validated using data from new board designs. The completed models, conveyor speed and preheat temperature, were used to predict values for the process parameters of the new board designs and then compared to the actuals. Predictions for the process parameters averaged within 2% or better of their actuals. Statistics for model building and validation data sets were compared and found to be close to each other. |
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| Item Description: | Vita. "Major subject: Industrial Engineering". |
| Physical Description: | xvii, 177 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references. |