Cycle Life of Test Probes

Cycle life is a very important consideration when selecting a spring probe. The number of cycles a probe will last depends on many factors which are unique to each application and the test environment. While applications vary widely, extreme conditions may exist. Some probes may be cycled once on clean contacts and maintained in the compressed condition, while others on a high production assembly line may experience tens of thousands of cycles. The rated mechanical life and resistance data is based on both the fatigue life of the spring and the internal sliding contact surfaces for probes, cycled in our controlled laboratory test environment. However in actual production, a test probe will typically encounter multiple environmental or physical conditions that will affect probe life. Some of these conditions may include:

  • Contaminants in the form of flux residues, oxides and other barriers present between the probe tip & test target
  • PCB’s manufactured with OSP coatings, Pb Free solder or using a no-clean process
  • Plunger tip wear or damage which may result from the UUT’s contact surface or plunger side-loading
  • Incorrect plunger stroke, resulting in reduced spring life or insufficient spring force
  • Extreme temperature variations outside of the recommended range
  • Surface particulates and/or other airborne chemicals in the atmosphere which may be drawn inside the probe

QA ships its products in protective packaging that contains Vapor Corrosion Inhibitors (VCI's). The VCI materials are designed to work in conjunction with the plastic bags and vials to protect the parts for a minimum of 2 years after which time the VCI’s dissipate and lose their effectiveness. By maintaining /renewing the VCI packaging, the storage life of the probes can be extended indefinitely. However the actual shelf life depends on the environmental conditions in which they are stored. By maintaining the parts in their original packaging and keeping the packages closed during storage the parts will maintain their designed performance levels.

Improper maintenance or handling of the test probe and or fixture We work closely with Test Engineers, Maintenance Technicians and Process personnel to make recommendations regarding fixture counters, probe tip styles, spring forces and tube materials. Developing a proper probe maintenance schedule will increase productivity, reduce false failure rates and ensure a higher level of First Pass Yields to help lower the overall cost of test.