| Summary: | 碩士 === 國立臺北科技大學 === 工業工程與管理系碩士班 === 103 === With the evolving electronics manufacturing industry technology of the surface mount technology (SMT) is main processes for the assembly of printed circuit board (PCBA). Approximately 52% -71% percent of soldering defects are attributable to the solder paste printing process and lack of quality control.
This study investigated the quad flat package (QFP) electronic components of pitch 0.4mm. Firstly, applying static parameters design to plan and conduct experiments. Using solder paste thickness as response a variable. To consider the potential influence of noise factors printing quality. Utilizing two phase optimize to decide the parameters levels of solder paste printing process. The results shows that squeegee pressure 11 kg, snap-off 0.14 mm, stencil cleaning frequency once in printing a PCB and cleaning the stencil with air gun blowing after wiping. In order to achieve process expected the specification, to reduce solder paste thickness at the sensitivity of the environmental factors, and improve process stability, simultaneously.
Next, put forth two inspection strategies with Taguchi quality loss function model, to assess that consumer loss in shipped with the product after have not been inspected and have been full inspected. The last strategy contain two kinds of inspection specifications for solder paste thickness, which previous literature suggests using the 3σ, and this study put forth the optimal solution η1σ, η2σ. In this case study, considering producing within specification limits and process variation, solder paste thickness drafting, the shipped-defect-products may cause consumer loss on the PCB. Exceeding the specification limit would lead to rework cost and inspection cost of the producer loss on the PCB. The results showed that in order to minimize total loss of per unit of product in process, the optimum inspection specification of lower and upper solder paste thickness are 110.3μm and 119.8μm.
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