Assessing lifetime and reusability

A custom in-house load solution can last as long as the product it is testing continues to be manufactured. For each new or different product, it’s likely that a new load solution must be fabricated—and this means incurring a new set of initial costs. The alternative is a commercial solution based on a flexible, modular architecture. With this approach, the possibility of retrofitting and reusing the commercial solution is much more likely for the testing of a new product.

The chart in Figure 2 compares the cumulative costs of in-house and commercial solutions over three new-product changes. The numbers are based on two assumptions: 1) the cost of changing the in-house design is the same as fabricating a new load solution; 2) the cost of retrofitting a commercial solution decreases with each change. In a high-mix/low-volume production environment, the number of changes can be even greater over a longer period of time, and this implies a bigger advantage for the commercial solution over time.

Figure 2. The cumulative solution cost over three new-product changes indicates that the commercial solution has an advantage.

This same concept can be leveraged for a shift in production capacity for different products. Figure 3a illustrates a production floor with four systems equipped with identical commercial load solutions. Each of these functional test systems includes a card cage and a corresponding selection of load cards.

Figure 3a. An example production line uses two sets of identical systems to support the testing of two different products.

Assume the following situation:

• Product A, which is being tested on Systems 1 and 2, is undergoing decreased demand, so the systems are running at 40 percent of capacity.
• Product B, which is being tested on Systems 3 and 4, is experiencing increased demand, so the systems are running at 80 percent of capacity.

Without further loading the capacity of Systems 3 and 4—and without building or purchasing a new system—a simple rearrangement of the load cards enables easy reassignment of either System 1 or 2 to the testing of Product B (Figure 3b). Comparing Figures 3a and 3b shows the effectiveness and life-extension made possible by the commercial solution.

Figure 3b. Refitting System 2 enables easy reassignment to the testing of Product B.

Maintaining a high utilization rate

Referring back to the COT formula, the ideal rate of utilization is always 100 percent—but this is not possible in practice. Fortunately, steps can be taken to sustain a high utilization rate by maximizing uptime and minimizing downtime. For any manufacturing line, three factors enable lower downtime:

• High reliability of the equipment
• Fast troubleshooting
• Readily available replacement parts

With an in-house load solution, troubleshooting time can be shorter due to deep familiarity with the design. It’s also possible to purchase additional parts to retain as spares, helping reduce downtime. Reliability is often the key shortcoming. If the focus is on creating the load box on a tight schedule, there is rarely time for any level of reliability testing prior to deployment.

For the commercial solution, reliability testing is a normal part of the development process. What’s more, manufacturers have statistical data that can be used to pinpoint which parts should be purchased as spares (for self-maintainers). If, as in Figures 3a and 3b, a common set of cards and card cages is used, then one set of spare parts can used interchangeably across all systems.

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