IEC60068-2-32 Part 2 Free Fall Test Standard Analysis
IEC60068-2-32 is an environmental test standard set by the International Electrotechnical Commission (IEC). Specifically, Part 2 Free Fall of this standard is mainly used to assess the performance and reliability of electrical and electronic devices when they experience free falls. This test simulates possible fall scenarios during the handling and use of the devices. Thus, it checks whether the devices have sufficient structural strength and impact resistance, ensuring they can withstand the effects of accidental falls in practical applications.
1. Test Objectives and Importance
The free fall test aims to determine whether the structural integrity, functional characteristics, and internal components of the devices are damaged during accidental falls. Throughout the product’s life cycle, from the transportation stage after production to daily use by consumers, fall accidents often occur. By conducting this test, potential weak points can be identified during the product design and production phases. As a result, improvements and optimizations can be made. This helps reduce the risk of malfunctions or damage caused by falls during actual use, ensuring product quality and user safety. Moreover, it enhances the product’s competitiveness in the market.
2. Test Methods and Procedures
2.1 Free Fall Test
2.1.1 Pre-test Preparation: First, visually inspect the test specimens according to relevant specifications to ensure there are no obvious defects in appearance. Then, conduct electrical and mechanical performance tests and record the initial state data. This data will serve as a basis for comparison later.
2.1.2 Determine the Drop Height: There is a series of standard values for the free fall height. Values marked with an * are recommended, namely *25mm, 50mm, *100mm, 250mm, *500mm, *1000mm. In actual tests, choose a suitable drop height based on the type, size, and expected usage scenarios of the test specimens. Generally, for large specimens, a very high drop height is not suitable. High heights may cause excessive impact, exceeding the range they might experience in normal use and failing to accurately simulate real – world situations.
2.1.3 Fix the Specimen’s Posture: Next, make the test specimens fall freely in the handling or usage postures specified by relevant specifications. Different postures lead to different impact force distributions and magnitudes during the fall. For example, when the corner, side, or front of a device hits the ground, the impact and potential damage vary. So, simulating possible real – world fall postures is crucial for accurately assessing product performance.
2.1.4 Execute the Drop Operation: Then, suspend the test specimens to the predetermined height, which refers to the closest distance between the specimen and the drop surface. When releasing the specimens, minimize any disturbances. Ensure the specimens fall freely from the suspension point to achieve a state closest to actual free fall. Unless otherwise specified in the specifications, usually perform two drops for each specified posture. This can eliminate the randomness of a single drop to some extent and more comprehensively detect the product’s performance when falling in that posture.
2.1.5 Post – test Inspection: After the drops are completed, visually inspect the specimens again according to relevant specifications. Check for obvious mechanical damages such as cracked or deformed casings, loose or detached components. Also, conduct electrical tests to check whether all electrical functions of the devices are normal. For instance, verify if the circuits are conducting, signal transmission is stable, and the devices can start up and operate normally. This helps determine whether the fall has adversely affected the electrical performance.
2.2 Repeated Free Fall Test
2.2.1 Pre-test Preparation: Similarly, before the test, visually inspect the specimens and conduct electrical and mechanical tests according to relevant specifications, and record the initial state.
2.2.2 Equipment and Setup: Repeated free fall tests are usually carried out using appropriate substitute devices, such as a rotating drum tester. Test each specimen separately, and usually connect a cable to the specimen. This simulates the situation of devices connected by wires in actual use, like connectors or remote controls. Unless otherwise specified, the length of the connecting cable should be at least 100mm.
2.2.3 Determine Test Parameters: Set the drop height at a fixed 500mm and the drop frequency at ten times per minute. Determine the number of drops according to relevant specifications. Alternatively, values such as 50, 100, 200, 500, 1000 can be used. These parameters are determined by considering the possible fall situations of such devices in actual use. They can effectively simulate the situation where devices frequently fall onto hard surfaces.
2.2.4 Execute the Test: Put the specimens into the rotating drum and start the machine. As the drum rotates, the specimens continuously fall from the predetermined height onto the test surface inside the drum. Stop the rotation when the specified number of drops is reached.
2.2.5 Post – test Evaluation: Just like the free fall test, conduct visual inspections, electrical, and mechanical tests on the specimens after the test. Judge the performance changes of the specimens under multiple drops by observing the mechanical and electrical changes. Then, determine whether they meet the relevant standard requirements.
3. Test Environment and Equipment
3.1 Test Environment
Conduct the tests under normal temperature and pressure conditions. Generally, control the temperature between 20℃ – 25℃ and the relative humidity between 45% – 55%. Such environmental conditions can eliminate the interference of environmental factors like temperature and humidity on the test results. Consequently, the test results can more accurately reflect the performance changes of products caused by fall impacts.
3.2 Test Equipment
Free Fall Test Equipment: It mainly consists of a suspension device and a drop surface. The suspension device should stably lift the specimens to the predetermined height and minimize disturbances when releasing them. The drop surface should be a flat, hard, and rigid cement or iron plate to simulate the hard ground that might be encountered in actual use. If there are special requirements, further describe and specify details such as the material, size, and surface roughness of the drop surface in relevant specifications.
3.3 Repeated Free Fall Test Equipment:
The core device is a rotating drum. The test surface is a 3mm – thick flat, hard, and rigid iron plate, with about 10mm – thick hardwood placed under the plate. This structural design ensures that the specimens receive sufficient impact while cushioning the impact force to some extent. It avoids test result distortion caused by excessive impact and more realistically simulates the situation of devices falling onto hard surfaces in actual use. If there are a large number of specimens to be tested, divide the rotating drum into several sections in a specific direction, and place one specimen in each section to improve test efficiency. For example, when the drum rotates five times per minute, it is equivalent to the specimens dropping ten times per minute.
3.4 Test Result Evaluation and Application
After the free fall and repeated free fall tests, comprehensively evaluate the test results based on aspects such as the appearance damage, mechanical performance changes, and electrical performance of the specimens. If there is no obvious structural damage to the specimens after the test, such as no cracks in the casing, no loose or detached components, and the electrical performance remains normal, meaning the devices can work normally and all performance indicators fluctuate within the specified allowable range, then the product can be considered to have passed the corresponding fall tests.
For manufacturing enterprises, test results can be directly used for product improvement and optimization. If products show problems such as insufficient structural strength or easily loosened connection parts during the test, enterprises can strengthen product structural design, improve material selection, and optimize the connection methods of components accordingly. Additionally, passing this test is an important guarantee for products to enter the market. Products that meet the IEC 60068 – 2 – 32 Part 2 Free Fall standard can gain more trust from consumers in the market. This reduces after – sales maintenance costs and the risk of brand reputation loss caused by product quality issues. In numerous fields such as consumer electronics products like smartphones, laptops, smart speakers, as well as industrial equipment and automotive electronics, this test standard plays an indispensable role in promoting the continuous improvement of product quality and reliability.
