When it comes to board test probes, one of the most common questions asked is, "How many cycles will probes last?" It's a valid concern, as probe life directly impacts maintenance cycles and the cost of testing. However, answering this question isn't as straightforward as providing a single number. Probe life is a variable that depends on several factors, and the answer, in essence, is: "Results will vary."

Understanding Probe Life

Smiths General Purpose probes, for instance, were rigorously tested during their design phase, demonstrating a capability of up to 1 million cycles. However, this impressive number is rarely achieved in real-world customer applications. To set realistic expectations, it's crucial to consider the following factors:

1. Tip Shape: The shape of the probe tip plays a significant role in its longevity. Pointier tips, especially when used against hard surfaces, tend to wear out faster compared to flatter tips with more surface area and similar force.
2. Force: Higher force exerted by a probe can also reduce its lifespan when compared to probes with lower force. Selecting the right force for your specific testing needs is essential.
3. Performance Expectations: Different users have varying performance expectations for their probes. Some may prioritize low contact resistance, while others may require only a reliable signal. This discrepancy in expectations can affect probe life.
4. Testing Conditions: The environment in which probes are used is critical. Smiths' tests are conducted in ideal conditions against, with flat gold plates, precise vertical alignment, automatic actuation, low controlled current, and in a clean laboratory environment. Real-world conditions may not always match these ideal parameters.

Improving Probe Life

To extend the life of your probes and lower the overall cost of testing, consider the following steps:

1. Tip Selection: Choose probe tips that are appropriate for your application. If possible, opt for radius tips with more surface area when a pointy tip is not essential.
2. Force Control: Use probes with the right amount of force required for your testing needs. Avoid excessive force that can accelerate wear and tear.
3. Compression Distance:  Avoid overtraveling of the probe to minimize unnecessary stress during testing.
4. Cleanliness: Maintain a clean testing environment to prevent contaminants from prematurely degrading the probes.
5. Current Control: Lower the current whenever possible as excess current can lead to spring failure. For higher current applications use Smiths Interconnect's High Current Probes
6. Test Fixture Quality: Invest in high-quality test fixtures to ensure that probes are used in a controlled and consistent manner.

Conclusion

In conclusion, the lifespan of board test probes is a variable that depends on a multitude of factors, including tip shape, force, performance expectations, and testing conditions. While it may be challenging to provide a definitive answer to the question of probe life, monitoring the performance of probes in your specific test environment and taking controlled steps to improve their longevity can help lower the cost of testing.

At Smiths, we understand that probe life is a complex issue, and we are here to help you reduce your cost of test. Contact us if you have questions or need assistance.

You can find all of our cataloged Board Test Products at the following retailers:

• www.mouser.com
• us.rs-online.com