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Introduction to environmental testing

Environmental testing: Introduction

Environmental testing is part of the work done by the Test and Measurement industry. Builders of test and measurement equipment do not produce end-user products. Instead, their equipment is sold to other companies who use it to test and verify the correct operation of the end-user products that they themselves manufacture, or of other third-party equipment that they use in producing their own products. For example, the companies that build voltmeters, oscilloscopes, and other electrical measurement devices are part of the test and measurement industry; as are the makers of calipers, gauge blocks, and other devices to accurately measure distances.

Environmental testing subjects a product to the stresses that it will encounter after it is manufactured, to ensure that it will survive and function correctly after enduring its shipping and in-use environments. Environmental tests can usefully be performed at several stages in the life cycle of a product. In the design phase, prototype testing can expose defects in design or inadequate materials or components. Testing the manufactured product can include stress screening, production testing, product qualification, or health monitoring.

In stress screening, the product is subjected to environmental conditions severe enough to identify defective components or faulty workmanship, but not so severe as to cause damage to correctly-manufactured products. Production testing is intended to detect faulty sub-assemblies received from outside vendors, as well as problems in the manufacturing or assembly process. Product qualification demonstrates the product’s ability to satisfy a particular customer requirement or specification. Health monitoring is performed to detect degraded performance or incipient product failure in time to carry out scheduled maintenance.

In all of these uses, the goal and end result of environmental testing is a product of improved quality and reliability.

Environmental Test Parameters

Each kind of environmental stress is called a (environmental) test parameter. There are many kinds of such parameters against which a product can be tested, depending not only on the nature of the product itself but also its transportation and in-use environments. Some important environmental test parameters are given below:

• Temperature (extremes of both heat and cold)
• Chemical solvents and reagents
• Electromagnetic noise (for electronic equipment)
• Acoustic noise
• Mechanical vibration, both steady state and transient
• Explosive overpressures (for military equipment near artillery)
• …

Specialized test equipment has been developed to perform environmental testing for each of the above test parameters. The equipment that tests against a certain parameter is designed to produce precisely measured amounts of that kind of stress in a laboratory environment, and to allow the experimenter to exactly repeat a test as often as desired.

Mechanical vibration is the environmental parameter of focus at Spectral Dynamics. A wide range of our products dealt with vibration: ED or hydraulic shakers, our controllers, the PIND Felix system.