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44 SMT007 MAGAZINE I MAY 2018 Development of the SMT Machine Model 1. Discovery that machine cycle times were poor After sample product simulations were run by Universal Instruments, it was discovered that observed cycle times were two to three times longer than simulated cycle times. This led to a focused effort to understand why. A kaizen event was held to map out the process and observe product builds. Several items that impacted the product cycle time were uncov- ered. These items were: 1. Component library placement speed slowed down. 2. Imbalance between placement beams/ heads due to not having enough nozzles to pick and place the required component packages for the products. 3. Bypassed nozzles and spindles. 4. Large quantity of placements from a single component input. 5. Panel transfer rate into and out of the machine slowed down. 6. Poor optimization and component split between machines on an SMT line. 7. Operator variation in responding to the process. The most significant item impacting cycle time was not having the necessary quantity of nozzles available for the mix of component packages for the products that the machine/line was building. To maximize flexibility to move products between lines, machines of the same type were equipped with a standard nozzle configuration. The nozzle configurations were changed only when a new component package was needed. To address this problem, a regu- lar nozzle review was implemented to ensure the machines have sufficient nozzles available to optimize the machine programs. Products were reviewed for the above issues. As items were addressed, the observed cycle times were reduced to align with the simulated cycle times. 2. Realization that cycle time does not represent SMT machine utilization Cycle time represents how a product is running compared to a benchmark but does not reflect utilization of a machine based upon its throughput capability. For pick and place machines, throughput can be measured in components placed per hour (CPH). Manufacturers provide CPH specifications for SMT machines in two ways. The first method is what is often called "Maximum CPH" [2], which represents the maximum speed the manufacturer was able to achieve and the second is based on "IPC 9850" [3], which has CPH categorized by package type. The "place- ments per panel" required to run these tests are shown in Table 1. The "IPC 9850" performance tests are useful to compare equipment models and manufac- turers to each other, but they do not necessar- ily represent the products manufacturers are building. This complexity can be understood by comparing Table 1 to the sample product complexity of global product mix in Table 2. Table 1: Sample of range of placements per panel to run IPC and manufacturer tests. Table 2: Sample range of placements per panel versus count of assemblies and forecasted panel volumes.