Every process must be done the same way, every time, by every operator. Consequently, manufacturing documentation must be very detailed. Using APM, hundreds of different assemblies can be on the floor at the same time. In addition, every document is written in an internal specification language implicitly understood by all team specialists. This standard documentation clearly states when IPC-610A Class III workmanship standards must be maintained and when device history records are needed for lot traceability.
Standardization also extends to equipment calibrations.
Maintenance technicians calibrate and maintain all duplicate equipment to the same standards so that when the recipe for a particular board is called up, that board can go to any system with the same results. Consequently, all SMT lines operate consistently, regardless of the product being run, and all reflow ovens produce the same process characteristics, even if the SMT lines consist of different oven models from various manufacturers. Because all production lines are certified to produce Class III products, it is not necessary for the AES to send a work order through a uniquely configured or dedicated line. APM is, by nature, a highly random scheme. The job of the AES is essentially to forecast the work load at a given process point in order to route each job to the next available station.