A reasonable first step in defining a complementary test strategy is to specify the preferred test system for each part number on a board based on test coverage and speed requirements, confidence in different test methods for different part numbers, and budgetary constraints.
Once you have completed your tests, PCB test software helps to eliminate the test bottleneck, facilitating the development of less costly complementary test strategies, and helps to check the viability of these strategies and identify design for testability issues more quickly. Once the test strategy has been finalized, the software speeds up the generation of shop-floor documentation, input lists, and target test systems, together with data required for fixture manufacture.
Quality engineers, plant supervisors, and managers need to see faults reported by test in real time, and must receive alerts if the faults exceed specified limits. Quality engineers need to determine whether the faults reported by test are caused by defects, and they need to be able to drill down to the root causes of defects so that corrective actions can be taken. If a defect has been introduced during the manufacturing process (e.g., a solder open), the process step responsible for introducing it needs to be identified and corrected to prevent recurrence.
It should be easy to determine whether a component defect is general in nature, if it only affects a particular batch of components, or is an isolated case. To enable the repair loop, the repair operator needs to be presented with board graphics that pinpoint defect locations on dense boards, together with historical data documenting successful past repair actions. Post-repair actions have been taken into consideration as well. All of these downstream processes can be managed by the new product information (NPI) and execution systems components of manufacturing process management (MPM) software. MPM's focus on process flow makes it particularly appropriate for test.
While there are several approaches to test process design and implementation, the wider range of applications, greater integration, and level of maintenance provided by independent NPI and executions systems software merit consideration in comparison with point solutions from equipment vendors and in-house solutions. Greater MPM value usually can be achieved by a more comprehensive independent approach that eliminates duplication, and is developed and supported in response to the needs of the global manufacturing industry.
This article was written by Antony Caulcutt, director of product marketing (NPI), and Santiago Cabezas, senior marketing manager, Tecnomatix Unicam, a subsidiary of Tecnomatix Technologies, Ltd. For more information, visit www.tecnomatix.com.