Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Parameter Control in Selective Laser Sintering for Elastic Lattice Structures of Functionally Graded Seat Cushion

Minkyu Seong, Yonghyun Kim and Namhun Kima

Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea


Lattice structures have been widely applied in many fields, including aerospace and automotive, due to its superior capabilities on energy absorption and weight reduction. However, with their complex shapes, it is often difficult to realize lattice structures with conventional manufacturing methods. In this sense, additive Manufacturing (AM) can provide with an excellent solution for implementing complex shapes of lattice structures due to the high design flexibility. Therefore, researchers and engineers have shown an increased interest in designing and applying lattice structures using AM. Especially, a lattice structure which is AM printed with an elastic material (e.g., a thermoplastic polyurethane (TPU)) provides flexibility and elasticity to the parts and functional designs. Previous studies of AM printed lattice structures have focused on energy absorption efficiency and packaging for product protection. However, far too little attention has been paid to applying additive manufacturing to seat cushions such as automobile seats. In this research, the effects of the process parameters on the sag factor and hysteresis loss rate of a Kelvin lattice structure produced through Selective Laser Sintering (SLS) process were investigated. The sag factor and hysteresis loss rate are properties quantitively defined to represent the comfort of the seat cushion. A design of experiment is designed with three main process parameters (i.e., Laser Power, Hatching Distance, and Scan Speed). The effects of the parameters on the cushion properties were assessed using analysis of variance (ANOVA). The optimal process parameter combination for the cushion properties that shows similar performances to existing automobile seat cushion was obtained using the response surface methodology (RSM). A confirmation test was conducted to verify the optimal process parameters by manufacturing a prototype of the seat cushion. It is shown that a seat cushion additively manufactured with a single material and SLS has multiple cushion areas by applying the combination of various process parameters.

Keywords: Lattice Structures, Additive Manufacturing, Thermoplastic Polyurethane, Process parameters, Cushion properties.

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