Cooling Fan Reliability Testing Case Study
Customer Challenge A customer approached DES looking to find an accelerated test solution for an AC powered cooling fan used in one of their products. The product had been established in the marketplace and the company was now looking for ways to reduce cost by looking at different cooling fan suppliers. Most fans, however, have a mean life rated for over 20,000 hours, so a typical accelerated life test would require a significant amount of time and money.
What Kind Of Failures Occur During HALT?
Product failures in HALT testing are defined as either the cessation of any functions or an out-of-specification condition for any performance characteristic. When a failure occurs, it is documented in DES’s HALT log. The exact time and test condition when each failure occurred is noted. If the product fails to operate, the temperature or vibration will be changed toward ambient room conditions followed by a short dwell period to see if the product recovers. If the product is non-operational after dwelling at ambient conditions, trouble shooting will take place to find the failed component. The failed component will then be…
What Equipment Is Used For HALT?
HALT Chambers 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.
What Is A Typical HALT Procedure?
HALT procedures vary from lab to lab but are typically performed similar to DES’s procedure which is summarized below. DES’s HALT procedure is divided into 5 Stages: Stage 1 – Temperature Step Stresses, Stage 2 – Temperature Ramps, Stage 3 – Vibration Step Stresses, Stage 4 – Combined Temperature &Vibration Stresses, and Stage 5 – Temperature Destruct Limits. Stage 1 is used to determine the HALT Operational Limits for temperature. The goal is not to cause destruction in Stage 1, but sometimes the operational and destruct limits occur simultaneously. The HALT Destruct Limits for temperature and vibration are typically found…
What Is HALT (Highly Accelerated Life Testing) And Why Perform HALT?
Highly Accelerated Life Testing (HALT) is a rigorous reliability test method that is used to expose product weaknesses. The goal of HALT is to proactively find weaknesses and fix them, thereby increasing product reliability. Because of its accelerated nature, HALT is typically faster and less expensive than traditional testing techniques. HALT can be effectively used multiple times over a product’s life time. During product development, it can find design weakness when changes are much less costly to make. By finding weaknesses and making changes early, HALT can lower product development costs and compress time to market. When HALT is used…
Temperature Cycling Testing: Coffin-Manson Equation
Temperature cycling testing is another method of accelerated life testing for products that are exposed to temperature variations during use in normal operation. The temperature variations can be a result of self heating for products that are repeatedly turned on and off, or can be the result of cyclic environmental changes — such as temperature variations from day to night — or other causes. These repeated temperature changes can result in thermal fatigue and lead to eventual failure after many thermal cycles. Accelerated life testing can be performed by cycling the product to high and low temperatures that exceed its normal use temperatures….
DES Adds New Unholtz-Dickie Vibration Test System
To keep up with increasing vibration and shock testing demand, DES added a brand new Unholtz-Dickie Electro Dynamic (ED) Shaker Test System. The shaker is a model SAI30F-S452/ST system with slip table to perform vibration and shock testing along 3 axes. This gives DES additional vibration and shock testing capability and also will help us turn your projects around faster.
Case Study: Combined Temperature & Vibration Testing of Automotive Mass Air Flow Sensors
Mass Air Flow Sensors (MAFS) are used to measure the mass flowrate of air entering engines in newer model cars. The mass air flow information is transmitted to the engine control unit (ECU) to balance and deliver the correct amount of fuel mass to the engine. These sensors operate in a very harsh environment, a car engine compartment! Testing their reliability and proving their durability is a very difficult task. Mass Air Flow Sensors (MAFS) Combined Temperature Vibration Testing DES was awarded multiple contracts to perform combined temperature and vibration reliability testing of Mass Air Flow Sensors from various automotive…
Delserro Engineering Solutions Featured in Desktop Engineering
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…
How a HALT Test Shows The Future
Highly Accelerated Life Testing Procedures Speeding up the process of device or circuit failure requires extreme inputs, those that are unlikely to occur during real-world use by customers regardless of the environment. Three common testing inputs are high and low temperatures, rapid cycling of the same and vibration along six-axes. In some cases, a highly accelerated life test (HALT) will incorporate combined temperature and vibration stresses. These inputs can result in component failure in the span of days, hours, or even minutes compared to months or years of typical usage. Benefits of HALT Testing While the percentages of failure…