Manufacturers of electronics and components go to great lengths to miniaturize the parts and equipment they produce, giving us greater advances in technology and more precise equipment. However, the small size also causes increased concerns over safety and reliability of these miniaturized components. A smaller size makes these products particularly susceptible to thermal stress. Serious temperature stresses can be inflicted during the manufacturing process or during end use. Manufacturers are now turning to severe methods of environmental testing to ensure that these products are of high quality and reliability.
Thermal shock is a method of environmental testing that subjects the product to alternating extremes of high and low temperatures. This type of testing allows for the observation of changes in product characteristics and failure occurrence caused by different materials and their thermal expansion coefficients. Although traditionally performed in accordance with military test standards, today most commercial reliability and quality control programs also call for rapid and extreme temperature changes. Thermotron offers several configurations of thermal shock chambers capable of meeting a wide variety of testing needs.
The vertical, two zone chamber has hot and cold zones that can be controlled independently. A single basket product carrier moves between the hot and cold zones, subjecting the product to dramatic changes in temperature.
Thermotron’s horizontal, three zone thermal shock chamber utilizes 3 temperature controlled areas; hot, ambient and cold. The product is moved from ambient to hot or ambient to cold zones. The chamber can be programmed to include a dwell period in the ambient zone if desired. Horizontal thermal shock chambers can be used to perform 3 zone or traditional 2 zone tests for added versatility.
Double duty thermal shock chamber from Thermotron are designed with hot zones above and below the cold zone and a two compartment product carrier simultaneously moves products between the hot and cold zones. This configuration makes better use of the chamber’s refrigeration system, increases machine efficiency and allows for more products to be tested in the same amount of time.
Thermotron’s thermal shock chambers are capable of a maximum temperature range from -73°C to +200°C (-99.4°F to +392°F). Most thermal shock chambers feature cascade refrigeration systems for full cooling using only mechanical refrigeration. All mechanically cooled models can also be equipped with LN2 or CO2 boost. Models cooled entirely by LN2 or CO2 are also available on certain configurations. Temperature/humidity programs are available in the hot box on some models. The chambers are available with product carriers ranging in volume from 1.0 cu ft (28 L) to 12.7 cu ft (360 L).
Thermal shock chambers are controlled by Thermotron’s 8825 Programmer Controller. This controller allows the chambers to operate both thermal shock and temperature cycling programs. The 8825 also provides built-in system status, monitor and alarm functions. Easy-to-use wizards make calibration,exporting test data and programming nearly effortless. A unique transfer basket graphical display illustrates where the transfer basket is when a transfer is made and shows which zone the basket is in.
Thermotron thermal shock chambers are as safe as possible. Relief valves and inherent overload protection has been included on refrigeration system compressors. ThermAlarm®, the most advanced temperature alarm/limit device available for temperature test chambers, is an option that provides audible, visual, relay and contact indication of a temperature exceeding a predetermined high or low limit. A transfer jam mechanism sends error messages to the controller and will not allow the transfer basket to move until the jam has been cleared. Door interlocks prevent the chamber from working if hot or cold box doors or electrical panels are open. Limit switches prevent user injury.
Thermotron thermal shock chambers have been designed to operate in accordance with reliability programs, quality control, commercial test programs and military tests including MIL-STD 202, 883, 810 and JEDEC.