How should product-thickness variation be included in testing a commercial X-ray inspection system?

Include minimum, typical, and maximum product thickness in the X-ray test and check performance across relevant density changes. Before comparing suppliers, fix the product specification, target throughput, and operating condition used for the test. During FAT, use calibrated instruments where relevant and keep the original readings with the acceptance record. The purchase specification should state the method, tolerance, sample quantity, and treatment of nonconforming results. Also confirm cleaning access, routine maintenance points, and the parts that operators must remove between production runs during normal operation.