Vacuum chambers have the capability to withstand the pressure caused by creating a vacuum, and are usually made from metals such as aluminum and mu-metal. As vacuum testing is used across a wide range of industries, it is possible that the chambers are designed and constructed with the capability of replicating certain environmental conditions of temperature and altitude in addition to creating a vacuum environment.
Environmental testing simulates the actual conditions a product is likely to face during its useful lifespan, and therefore more than one environmental effect is necessary to get an accurate idea of how a product will respond. In order for the engineer to watch the results of a vacuum upon an object, there is typically a viewing port or window sealed with rubber. Sizes of vacuum chambers can vary greatly, from smaller benchtop chambers used to test miniature components and objects, to larger chambers able to encompass objects of a much larger nature.
Several industries rely on vacuum packaging to help produce the best quality product possible. Aerospace engineers use vacuum testing for all the components of space travel equipment, which have to be able to withstand the effects of a vacuum and low pressure environment for extended periods of time. Vacuum testing can be undertaken on spacecraft electronics and circuits, lenses and filters and coatings and structural materials. Vacuum molding plastic manufacturers use vacuum chambers when mixing resins and silicone rubbers to ensure a bubble-free mold replica. The material to be inserted into the mold is placed in a vacuum chamber to remove all existing air bubbles, and to make it ready to pour into the mold without leaving blemishes. Vacuum chambers are also used for testing the sealing in packaging and the potential for leaks and possible malfunctions under pressure. This is useful especially for export packaging where goods will be subjected to high altitudes during transportation by air and in the pharmaceutical and medical industries where it is necessary for medicines to remain sealed until use. Vacuum testing can take many hours and can be a costly procedure, and yet it is a wise manufacturing choice to undergo environmental testing, especially in terms of long-term expenditure.