Thermal shock testing also called temperature shock testing or temperature cycling exposes products to alternating low and high air temperatures to accelerate failures caused by repeated temperature variations during normal use conditions. The transition between temperature extremes occurs very rapidly during thermal shock testing, greater than 15 °C per minute. Alternatively, temperature cycle testing uses slower rates of change between high and low temperatures. The failure acceleration rate for thermal shock testing is determined by the Coffin-Manson equation as previously discussed in DES’s blog article Temperature Cycling Testing: Coffin-Manson Equation.
Equipment with single or multiple chambers may be used to perform thermal shock testing. When using single chamber thermal shock equipment, the products or samples remain in one chamber and the chamber air temperature is rapidly cooled and heated. This usually results in a slower rate of change in the product response temperature as the entire chamber must be cooled down and heated up. However larger products can be tested in single compartment chambers. Some equipment uses separate hot and cold chambers with an elevator mechanism that transports the products between two or more chambers. This results in a more rapid rate of change in the air temperature. However, there is a limit to the size and weight than can be put in a chamber with an elevator mechanism. DES has both types of chambers for thermal shock testing.
Specialized test chambers are needed to perform a HALT. Typical HALT chambers are shown in Figure 1. The specification for HALT chambers is typically the following:
Liquid nitrogen (LN2) is used to cool the air temperature in HALT chambers. This allows for very rapid temperature changes of 60°C per minute and a cold temperature extreme of -100°C.
HALT chamber heating is provided by high power resistive heating elements that can produce changes of 60°C per minute and a hot temperature limit of +200°C.
Delserro Engineering Solutions (DES) was honored to be featured in a recent article discussing the capabilities of engineering testing companies. The article highlighted the benefits, in terms of both design and cost, of adequately testing designs, preferably as early in the process as possible. It also discussed the ins and outs of partnering effectively with a reliability testing facility.
The goal of this article was to teach product developers how to get the most bang for their testing buck; a goal that aligns perfectly with DES’s philosophy. No matter what your testing needs are, be they HALT, HASS, or other environmental or stress tests, DES is able to help you design and implement the most comprehensive and accurate test possible. As always, our client’s success is the source of our satisfaction. Continue Reading Delserro Engineering Solutions Featured in Desktop Engineering
DES added another larger AGREE Chamber to perform Combined Temperature and Vibration Testing. This gives DES additional capability to perform combined environmental testing on larger products. DES has performed Combined Temperature and Vibration Testing on car engine sensors, helicopter sensors and outdoor heavy industrial products. Some of the test specifications include MIL-STD-810 and General Motors GMW 3172.
The Equipment Capabilities Are:
- Combined shock or sinusoidal, random, mixed mode vibration and temperature
- Temperature range from -80°C to +180°C (-112°F to +356°F)
- Temperature rate of change up to 20°C/minute
- 9 cubic feet interior work space, cvo
- We completed a Pyroshock test on our Mechanical Impact Pyroshock Simulator (MIPS) on equipment that will fly into outer space.
- On the other end of the altitude spectrum, we completed environmental testing of components that will be used in submarines to MIL-E-917. MIL-E-917 is a military specification for Naval shipboard electric power equipment.
- In the middle of the altitude range, we performed combined temperature and vibration testing on sensors that will be used in automobile engines to specification GMW 3172. GMW 3172 is a General Motors Specification for electronic component durability.
The following is a sample of some additional testing projects we have completed recently:
This article discusses the reliability challenges of switching over to lead-free solder and the test methods used to demonstrate reliability, written by Gary Delserro and published in Evaluation Engineering Magazine. Click on the link to download the article in PDF, Lead Free Solder Reliability Issues & Test Methods.
Environmentally friendly is a term rapidly invading the electronics industry.
The electronic industry will be facing great challenges over the next few years as the solder used in electronic products is migrating toward lead-free. This is being driven by mandates in Europe such as Waste Electrical and Electronic Equipment (WEEE) and Restrictions of Hazardous Substances (RoHS) and similar ones in Japan. There also is a great deal of pressure in the US to do the same.