Issue link: https://iconnect007.uberflip.com/i/1372612
58 PCB007 MAGAZINE I MAY 2021 6S methodology is not new. e process is focused and disciplined. e process is DMA- IC [1] : Define–Measure–Analyze–Improve– Control. Use various tools, including Pareto charts, histograms, process control charts, and fish- bone diagrams. Use logic; think critically and strategically. Basically, it is quite simple: De- velop the troubleshooting skills necessary to solve process problems efficiently. e rule of thumb is to keep the trouble- shooting project as manageable as possible. Brainstorm to understand the linkages in the upstream and downstream processes and po- tential effects of process variation in these pro- cess steps. Gather all pertinent information in- cluding SPC charts, temperature logs, analysis records (including records of calibration and analytical standards), and the like. en devel- op a cause-and-effect diagram. Fishbone dia- grams serve this purpose well. At the risk of having hundreds of factors to investigate, only the most likely causes should be investigat- ed first. is is where experience and critical thinking skills come into play. is will serve to weed out those processes that are not contrib- uting to the defect. When was the process audit performed, and on what operations within the PWB fabrica- tion operation? Ongoing process audits joint- ly and separately performed by your supplier and designated individuals in the fabricator's facility should be standard operating proce- dure. Process audits alert the manufacturer if a process is "driing" out of the control win- dow. Suggest your company select an experi- enced group of operators, engineers, and oth- er science disciplines to be trained in the art of conduct a process audit. Table 1 shows an example of one such check- list. Outer Layer Dry Film Developing A fishbone diagram is another extremely useful tool to conduct root cause analysis of the problem [2] . Your team can use the fishbone diagram (Ishikawa diagram) to explore the po- tential causes of a particular issue or defect. Af- Table 1: A sample checklist for conducting a process audit for outerlayer dry film developing process.