Masters Theses

Date of Award

5-2000

Degree Type

Thesis

Degree Name

Master of Science

Major

Environmental Engineering

Major Professor

R. Bruce Robinson, Chris D. Cox

Committee Members

Bruce Tschantz

Abstract

The main source of wastewater contamination in the printed wiring board industry is from drag-out of process chemicals during the manufacturing process. Previous drag-out prediction equations are primarily a function of fluid viscosity and board withdrawal rate, and do not account for the many additional variables common in industry. A series of laboratory drag-out experiments were conducted on simulated alkaline cleaner/conditioner and microetch process baths to quantify drag out volumes for a range of fluid properties and process variables. Results of the experiments compared favorably with published drag-out volumes. The mean dragout volume for all experiments was around 91 mL/m², with literature values ranging from 16 to 203 mL/m². The results also indicate that previous predictive equations do not consistently predict drag-out for the range of variables in PWB manufacturing. Predictive equations for the alkaline cleaner/conditioner bath predicted values ranging from about 65 percent below to 40 percent above measured values. Two equations performed very well for the microetch bath, predicting values within 8 percent ,but others predicted poorly at 40 to 75 percent below measured values.

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