Most folks associate quality improvement initiatives with upfront expenses and ongoing cost increases. Fortunately, when done efficiently and with enough forethought and planning, quality improvement programs can pay for themselves in the form of increased throughput, reduced labor steps, and reduction in materials consumption. Increased yield improvements are then a pure bonus. The following project, centered on Saturn’s LPI solder mask operation, was implemented about 13 years ago and details just such an example. It was one part of a comprehensive review of our processes prompted by customer complaints of scratches on their incoming PCBs. The results, including a customer award, galvanized us to our current continuous improvement modus operandi.
Cleanroom Fixes Following LPI solder mask application, panels were partially cured in a tunnel oven and then scheduled for LPI imaging. A number of cosmetic defects were found to be related to mishandling and air cleanliness of the imaging area. To reduce mishandling, a new transportation cart system was implemented. To reduce opens due to dust, the entire area was enclosed with clean room curtains and station HEPA filters with particle counting machines.
