Reliability testing is an engineering field, that deals with the ability of a system or component to perform its required functions under stated conditions for a specified period of time. The main objectives of Reliability Testing can be defined as follows: The capacity of a device or system to perform as designed; The resistance to failure of a device or system.The ability of a device or system to perform a required function under stated conditions for a specified period of time.
To determine the ability of component parts and materials to avoid dielectric-withstanding-voltage failures due to the lowered insulating strength of air.
The barometric pressure test is performed under conditions simulating the low atmospheric pressure encountered in the non-pressurized portions of aircraft and other vehicles in high altitude flight. This test is intended primarily to determine the ability of component parts and materials to avoid dielectric-withstanding-voltage failures due to the lowered insulating strength of air and other insulating materials at reduced pressures. Even when low pressures do not produce complete electrical breakdown, corona and its undesirable effects, including losses and ionization, are intensified. Low barometric pressures also serve to decrease the life of electrical contacts, since intensity of arcing is increased under these circumstances. For this reason, endurance tests of elector-mechanical component parts are sometimes conducted at reduced pressures.
Low-pressure tests are also performed to determine the ability of seals in component parts to withstand rupture due to the considerable pressure differentials which may be developed under these conditions. The simulated high altitude conditions of this test can also be employed to investigate the influence on component parts operating characteristics, of other effects of reduced pressure, including changes in dielectric constants of materials; reduced mechanical loading on vibrating elements, such as crystals; and decreased ability of thinner air to transfer heat away from heat-producing components.
RELIABILITY VIBRATION TESTING
To determine resonant frequencies of the product in order to provide adequate protection and reliability of the product.
The vibration test is used to determine the effects on component parts of vibration within the predominant frequency ranges and magnitudes that may be encountered during field service. Most vibration encountered in field service is not of a simple harmonic nature, but tests based on vibrations of this type have proved satisfactory for determining critical frequencies, modes of vibration and other data necessary for planning protective steps against the effects of undue vibration. Vibration, by causing loosening of parts or relative motion between parts in the specimen, can produce objectionable operating characteristics, noise, wear, and physical distortion, and often results in fatigue and failure of mechanical parts.
To verify reliable functionality of the product when exposed to thermal extremes of temperature, humidity and altitude.
Temperature extremes, temperature cycling and humidity can lead to unexpected failure, unreliable operation of the product and may propagate and/or compound consequential failures, if not adequately addressed at the design stage. Test-O-Pac can replicate man-made and natural climates to support qualification testing for demonstrating compliance against a broad range of climatic test specifications and environmental conditions.
Combined humidity and temperature testing:
The combination of variable humidity and temperature are a particular concern for the design of electronics, where moisture build up may lead to short circuiting and product failure. Similarly, high and low humidity can effect electrical characteristics such as increased conductivity at higher humidity or electrostatic discharges at lower humidity. The Test-O-Pac’s range of temperature and humidity test chambers including walk-in chamber, can simulate environments of 10% to 98% relative humidity.
In addition to conventional temperature / humidity testing, Test-O-Pac can also provide a combination of temperature and altitude, or dual temperature (e.g. input fluids conditioned at a different temperature to the unit under test) providing the most comprehensive climatic test solution in California.
High and low extremes of temperature can significantly alter the mechanical and electrical properties of a product, such as the brittleness of components, viscosity of lubricants, electrical conductivity and ocillator frequencies. Extreme temperature testing can simulate temperature extremes cycling from -70°C to +120°C.
Diurnal or cyclic temperature testing is the process of cycling through temperature extremes and can be used as an environmental stress test to evaluate products reliability and to identify latent defects by inducing failure through thermal fatigue. Temperature cycling induces stresses due to the differing expansion / contraction rates of materials and can be a particularly hostile environment for electronics and precision moving parts or may cause blistering or cracking of surface finishes which may lead to subsequent corrosion failures. Temperature cycling tests can be conducted under passive or active conditions, with continuous monitoring to identify intermittent faults. For extreme thermal shock conditions, Test-O-Pac operates a dedicated thermal shock chamber, in addition to the manual transfer solution, depending on the product size.