The mechanical impact of consumer products are usually under two conditions: one is during transportation when the vehicle is on a rough road and bumping around or loose cargo; or when the product is dropped during handling. Handheld products (cell phones, PDAs) could be severely damaged by heavy impact if the product doesn't have a protection to absorb mechanical shocks. If the product is installed on automobiles, then its environment is worse than normal, especially those in areas that have higher shock protection standards such as wheels, doors, or in the trunk (boot). Therefore, when a product is in the designing stage, mechanical shock testing plays a critical role in understanding the structure of the product and packaging absorption issues.
International Electrotechnical Commission (IEC) has set up standards for system/ module mechanical shock testing shown in Figure 1. Most of the testing used to employ half-sine waveforms. In recent years, square waveforms are more common. The test units are often unpackaged and test orientations are on three axes (six faces) conducted with three shocks on each face. The recommended criteria is at least three test units must past standard.
At the same time, IEC has set up standards for system/ module bump testing shown in Figure 2. Bump testing is usually divided into two categories: packaged and unpackaged. In particular, the automobile electronics testing is based on standards and conducted on three axes (six faces), but the number of bumps depends on how strict the criteria is chosen (for more information, see Figure 2).