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82 SMT Magazine • September 2017 count for anticipated or unanticipated time out by any of your staff. This is called the Load Factor used to recognize the loss due to utiliza- tion, efficiency, absenteeism, etc. 6. All appropriate work centers have been identified. For any good CP tool to work properly you need to capture as many touch labor points as possible. The more finite the tool the more ac- curate it can be. In the EMS environment, most standard PCB process steps average approx. 12- 15 work centers and with a standard Box Build or system integration area somewhat less at 8-10 work centers. For more complex high-level as- sembly (HLA) such as fluid, pneumatics, hydrau- lics, gears, motors and other moving parts then the average work centers may climb to 18-20. Work centers should not be confused with process steps. Process steps may range in the hundreds if not higher. These would be the ac- tual steps involved in putting the product to- gether. Work Centers are the stops along the way that the product will go through to be pro- cessed. In a typical PCB assembly, these may in- clude process steps like, Audit, Prep, SMT, Post- wave (Secondary Ops), Wave Solder, Test, QC, Package, etc. These steps will vary a little de- pending on the EMS provider. Each of the as- semblies you are creating labor standards for should have a standard for each of those de- fined steps that it passes through (see Table 1). In Table 1, we have an assembly that has 1.1 hours or 66 minutes' worth of applied labor es- timated for each product. If we know our lot size was 100 units then it would be easy to esti- IMPLEMENTING A CAPACITY PLANNING TOOL Figure 6: The inspection team auditing the standard work process to ensure SMT equipment is running to capacity. Table 1.