Drop Test System with Orientation Repeatability for 3C Products

Abstract

Manufacturing of 3C (computer, communication and consumer electronics) products toward weight-reduction, thin-wall and minified-size is an inescapable trend for the future 3C industries. As a result, impact-induced damage becomes a great concern in design engineer regarding the robustness and reliability of 3C products. Traditionally, the mechanical performance of 3C product is mainly verified through physical drop test, which vast investment in cost and time is spent on proto-type model and development of experimental setup. It is necessary to know the impact force, acceleration and impact orientation when the products contact the ground. In this study, a physical drop/impact test system had setup. The drop/impact test system, associated with impact orientation control mechanism, fast speed visual surveillance system, and data acquisition/processing system is completed. A set of correlated spatial equations provides a relative accurate methodology to estimate the impact instance orientation, which is a key factor to structure design from impact damage. Based on the current study, it shows that drop/impact simulation plays an important role in design requirement of thin-wall products. It was found that this system provides excellent repeatability on impact angle control and spatial orientation analysis. Drop test for mouse housing is carried out at four different designed orientations and 50 tests are performed in each drop orientation. As long as the repeatability can be well controlled, a single frame, instead of continuous frames as taken by the HSC, is able to serve such a purpose with certain confidence levels. The repeatability of this tester is verified by four different drop orientation tests. The statistics show that the repeatability of the current drop tester can be achieved at 97.2% within plusmn5deg from a total of 200 drops. Finally, the maximum accelerations from the accelerometer outputs also indicate that those tests are very consistent. Therefore, it is crucial for the CAE users to understand the correlation effects between the simulation variation (such as structural stress/strain, impact force and acceleration), impact parameters (such as material definition, impact instance angle, part connection definition, etc.) and structural mechanical performance. Drop-impact performance should be well recognized during the product design. Experimental validation, robust modeling, analysis skill, and material property databases are the key factors to a future application. Accurate control on impact angle variation, impact acceleration, and numerical simulation are investigated and presented.