Time-to-production

Demand forecasts are estimates and can therefore be unpredictable for new product introductions (NPIs) and existing products. Shorter-than-expected TTP or unexpected changes in a project schedule can set off a chain of cost increases.

Figure 4a illustrates the process of developing a new in-house load solution for an NPI. The cost profile is quite different from that of a commercially developed solution, which is shown in Figure 4b. Advantages of the latter include predictable delivery time; the elimination of design and fabrication time; and shorter TTP.

Figure 4a. Investment versus time for a test-development process that uses an in-house design

Figure 4b. Investment versus time for a test-development process that uses a commercial solution

As an additional benefit, the time savings enable the test engineer to focus on value-added areas such as debugging or qualification of the new product. Spending more time on these areas can result in better test coverage, which will have a positive effect on COT.

Summarizing: Side-by-side comparison

All of the foregoing can be condensed into the convenient comparison shown in Table 1. This summary will be useful when deciding to make or buy the required load solution.

Table 1. A side-by-side comparison of the two alternatives

Conclusion: In-house or commercial?

In a manufacturing environment, every element of cost flows to the bottom line. Selecting a suitable COT/TTP strategy for load solutions is a small part of the overall production strategy but it can provide significant savings in terms of both time and money.

Self-designed load solutions offer control over design and fabrication. In a low-mix/high-volume production environment, they also provide the benefit of minimal changes over a long lifetime.

Commercial solutions provide a higher rate of reuse, extending the overall lifetime of the equipment. This also leads to lower cumulative costs in a high-mix/low-volume environment that demands flexible capacity and frequent system changes. Further, standardizing on this approach allows it to be leveraged as part of a common test strategy. This creates commonality in multiple areas: rules and operating parameters; troubleshooting methodology; and support replenishment strategies. The combined effect is to provide additional benefits in time and cost.

As a starting point, evaluate each strategy as early as possible in the development of a test system. Look beyond the initial fixed-cost investments and consider the total cost envelope of each approach. With careful planning, you can select the best pathway to a lower cost-of-test in functional test.

References

• Implementing Loads for Automotive Functional Test, Bob Stasonis, International Test Conference, October 2003
• Cost of Test – The Components, Contributors and Ways to Reduce, Mike Clayton, Agilent Technologies, April 2002

About the author

Yeap Hock-Yew is a product manager in Agilent Technologies’ Measurement Systems Division. He has been involved with automotive functional test systems since 2005, concentrating on marketing, business development and the conceptualization of next-generation test systems. For any inquiries related to this article or Agilent's automotive functional test solutions, please contact derek_ong@agilent.com.