NC State
Matthews, S., Toghyani, A. E., Ovaska, S.-S., Eskelinen, H., Kärki, T., and Varis, J. (2016). "Post-extrusion processing of extruded wood plastic composites and selection of belt conveyor cover material," BioRes. 11(3), 7001-7015.


Wood plastic composites (WPCs) have recently gained increased market share as a result of their beneficial properties and use of sustainable material sources. Currently, however, WPC products are limited to extruded profiles. More complex product shapes and geometries will increase market potential, but they demand additional post-processing after extrusion. Post-processing machinery coupled online with an extruder necessitates material handling, which is commonly achieved using belt conveyors. This paper considers transport of WPC material through a post-extrusion process using a belt conveyor system. Special emphasis is placed on studying the friction and surface energy properties of the belt conveyor. Friction at the interface of the raw material and belt cover was tested using a standard incline-plane method, and adhesion and stickiness were evaluated by determining the surface free energies of the belt cover and WPC material at 23 and 100 °C. On the basis of these measurements, this paper investigates key aspects of belt cover material selection and proposes a conveyor belt configuration for a prototype post-extrusion process line that can be utilized in commercial mass production of WPC products.

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