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October 2015 • The PCB Magazine 51 ticipated in a Kaizen. Most companies, how- ever, do not add the quality discipline of six sigma to the process and therefore do not ef- fectively measure the small continuous im- provements and reduction in process variation that should be at the core of every company's lean initiative. It all begins with a process flow diagram. One of the most frequent mistakes a company makes while developing the process flow dia- gram is that it is completed in a vacuum, by the process owner or engineering support per- son. To be robust and accurate, the process flow diagram must be developed as a team activity. Team members should include process owners, technical experts, production operators, super- visors, and support individuals such as man- agement, engineering, quality, etc. The inputs for the process flow diagram include observa- tions, brainstorming, work instructions and a complete review of the 6Ms: man, machine, material, measurement, method and mother (nature). Every step, no matter how small, must be included. This includes inspection, go/no-go decision and data collection point—in effect— everything. When developing the process flow, observa- tion techniques are critical. We all know what we think the process is. We can refer to our SOPs and find what the process should be. But we often find that the actual process flow has changed somewhat from these views—to what the process actually is. This is the flow we must diagram. In a complex manufacturing environ- ment the process operators are often the people with the most accurate information. They need to understand that their contribution to docu- menting the accurate process flow diagram as of today is necessary, and that any undocumented changes they may have made to facilitate the operation need to be documented now. So ob- serve and record. Observe over all shifts and on all machines. Observe all operators and verify all process parameters and machine settings meet the previously documented requirements. If anything has changed, only document the current situation. With the process flow diagram complete we begin the task of identifying which are the value add processes and which are not. Value- added process steps will change the form, fit or function of the board. As an example, the drill- ing process is a value-added process. We need to put the holes in the board—without the holes the board will not function and the customer's requirements will not be satisfied. By contrast, waiting for someone from the drill storeroom to bring the correct size drill bits so that we can start the job is a non-value added process. It's waste. Wait time is wasteful and non-value added. A well-defined process flow diagram will provide a tool that can highlight all types of waste as well as hidden factories. Hidden facto- ries abound in the PCB manufacturing environ- ment and include those workarounds we create when things aren't functioning correctly or any type of product rework. Some examples of waste are over-production, wait time and of course defects. These are all areas for improvement. If you are doing touch-up after imaging or remov- ing unetched copper at AOI inspection, your process has a hidden factory. Hidden factories have become such a part of our manufactur- ing expectation that we have even developed specialized equipment to complete the hidden factory tasks instead of fixing the process and eliminating the waste. The value Stream The next step in the process is to complete a value stream analysis. The optimized value stream will only include the actions that the PRACTICAL APPLICATION OF LEAN SIx-SIGMA TO DRIvE CyCLE TIME REDUCTION, PART 1 FeATure " When developing the process flow, observation techniques are critical. We all know what we think the process is. We can refer to our sops and find what the process should be. "