The application of BASF's Ultrasim® simulation tool has been further expanded to accurately predict the foaming and curing of the polyurethane elastic self-skinning foam system Elastofoam® I for automotive steering wheels. Through a detailed simulation process, the tool can accurately calculate the key chemical reactions and flow characteristics of polyurethane foam in the mold. This simulation takes into account the process environmental conditions such as temperature, pressure, material density, and special components such as metal skeletons and cables during the process. In addition, the upgraded Ultrasim also performed a detailed analysis of the entire foam material system for the first time. It is like providing a virtual magnifying glass for developers to help them identify key pores in components, adjust vent holes, and produce them as early as possible. A stable steering wheel manufacturing process was designed before the mold. This new BASF service will help steering wheel manufacturers shorten the development cycle, thereby reducing costs, while promoting the integration of steering wheel functions and improving their electronic and personalized design. Currently, users of the tool include auto suppliers such as Trina Automotive Safety Systems Co., Ltd.
Not afraid of complex flow characteristics: Predicting exhaust holes and density distribution accurately
The steering wheel is the most important operating component in a car: its feel, appearance, and functionality are directly related to the design of the component. Considering the complexity of the structure and shape of the steering wheel-including metal skeletons, cables, buttons and feature designs, and limited interior space, the requirements for polyurethane foam materials and foaming processes are higher. In the simulation analysis process, the developer must collect rich material data and consider complex material laws, because they will affect the filling characteristics and the final density distribution. Compared with the dashboard and other components, the accuracy of modeling must be improved when analyzing the flow characteristics of the foam of the steering wheel: the flow channels are separated and compounded, the small slot holes must be left empty, and the thicker parts must be filled and filled.
The exhaust performance of the mold is a particularly important parameter. During the production process, the manufacturer uses a variety of processing methods to ensure breathability. The vent holes are provided to prevent the appearance of holes in the parts that impair the stability and appearance of the steering wheel. The filling simulation function in the Ultrasim tool can accurately predict the position and size of the pores, helping customers to properly arrange the vent holes, thereby reducing the risk of pores with a relatively simple and breathable design. The precise flow model also takes into account individual components and customer-specific processes, such as installing mold pivots in the foaming process. In these applications, the comparison between the analysis results and the customer's finished product is sufficient to verify the accuracy of BASF's simulation tools for predicting the flow characteristics and porosity.
BASF simulation tools can also calculate the density distribution. The density distribution determines whether the touch of the steering wheel can meet the requirements of the car manufacturer, such as surface hardness. In order to predict the density of parts everywhere, BASF has improved the material model used by Elastofoam I to enable it to describe the expansion of foamed materials based on chemical reactions, changes in ambient temperature, pressure, and initial gas concentration. For further description The processing flow of polyurethane foam steering wheel and the basis of judging its mechanical properties such as stiffness and hardness are laid. At present, the Shore hardness of the steering wheel cannot be predicted at the earlier stage of pure virtual projects, but it can be checked in physical tests.
Elastofoam I elastic self-skinning foam: lightweight inner core, hard outer skin
In addition to existing technical services, BASF has also combined with the new Ultrasim tool to further develop customized manufacturing services for flexible self-skinning foam systems to meet specific process and component application requirements. The existing one-step processing method can be used to process the Elastofoam I self-skinning steering wheel system with lower density, beautiful appearance, UV resistance and scratch resistance. The outer surface of the steering wheel is hard and sturdy, soft and comfortable to the touch, superior in abrasion resistance, and resistant to sweat, sunscreen or detergents, and durable. Currently, such foam systems can significantly reduce weight by 340 grams per liter, while maintaining faster demolding speeds (60 seconds) and lower emissions.