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52 The PCB Magazine • October 2015 customer would be willing to pay for to bring the product or service from start to finish. If we remember the drill room example from the pre- vious section, most customers will not be will- ing to pay for a wait time created by not having the tool ready when the boards arrived at the drill machine. The customer would also not be willing to pay for the rework process to correct the defect of unetched copper. We begin the process by recording the in- formation we need using a standard work sheet that documents the physical area layout and flow of material through all of the process steps. This can be looked at either by part flow or by showing people movement. Next is the time observation sheet (Figure 2) which is just what it sounds like: a tool to collect the process times for one cycle. Time observation records the time it takes to make one piece or batch, to do one task or one set-up. We can use time obser- vation sheets to subdivide our work into prod- uct types such as HDI or flex as an example. The time observations sheets should record the time and process differences for each unique product type. We can also use it to differentiate between different workers. Data from time observation can be used to predict cycle time based on basic steps in the production cycle. As an example, if the process has one set up, one break down, and will generate 18 production panels that con- tain 10 PCBs each (180 boards), the predicted cycle time is: cycle Time = (1*Set-up Time) + (180*Piece Time) + (1*Breakdown Time) Next is the percent loading chart (Figure 3) using the time observation information. When there are multiple people involved in a process we use a percent loading chart to show the re- lationship of multiple people's contribution to the process. Once the time observations are PRACTICAL APPLICATION OF LEAN SIx-SIGMA TO DRIvE CyCLE TIME REDUCTION, PART 1 FeATure Figure 2: Time observation sheet: drilling.