Test time is the duration of executing a testing sequence. Cycle time is a duration that includes test time, material handling time, and all before and after activities necessary to execute a test sequence.
Logical Inferences & Experience
- Cycle time is equal to or greater than test time
- Production leaders are interested in cycle time. However improving test time improves cycle time.
- Understand whether "test time" as a percentage of "cycle time" is significant; if the percentage is greater than 33.33%, it's significant.
- When "test time" as a % of "cycle time" is (a) significant and (b) easier to improve on an ATE, then improve test time first. It's productive to resolve what you can immediately control (test hw/sw). Otherwise, focus improvements on overall cycle time.
- Understand the tolerances of both "test time" and "cycle time". Reducing the "average test/cycle time" is noticeably beneficial, when the tolerance are are a fraction of the "average test/cycle time". Otherwise, wide time tolerances can mask gains.
- When tolerance are wide, first focus on tightening test time variation.
- There can be a trade off between test times and the "false-failure-rate". Improve one and the other can sometimes degrade.
- Know the floor-test-time-function of products tested, independent of the test systems. A high performance test system operates closer to the floor-test-time-function.
