Fine-Tuning the Stencil manufacturing Process & other stencil printing experiments

Previous experimentation on a highly miniaturized and densely populated SMT assembly revealed the optimum stencil alloy and flux-repellent coating for its stencil printing process. Production implementation of the materials that were identified in the study resulted in approximately 5% print yield improvement across all assemblies throughout the operation, validating the results of the initial tests. A new set of studies was launched to focus on the materials themselves, with the purpose of optimizing their performance on the assembly line. Using a similar test vehicle as the prior experiments, DOEs characterized key aspects of the stencil manufacturing process by varying the laser cutting parameters and coating materials. As the scope of the DOE grew, it also included evaluation of new materials and a comparison of microBGA aperture designs. Eventually, additional runs were added to investigate the effects of nanocoating on wipe frequency and compare two different stencil cutting processes. Results of the prior tests are reviewed, and the new test vehicle, experimental setup and results are presented and discussed.