Effects of pellet shape on the flowability of resin pellets in hopper

Abstract

There is a growing demand for higher performance and thinner communication cables (LANs and USBs) that can transfer data in large volumes at high speed in the era of IoT, 5G. Fluorine resins having a lower dielectric constant and a lower dielectric dissipation factor are used as coating materials for high performance electric wires. To coat the electric wires stably at high speed, it is necessary for resin pellets to flow smoothly from hopper into cylinder in an extruder. In this paper, we propose a simulation method based on the dynamic explicit FEM (Finite Element Method) to evaluate the flowability of resin pellets which are filled into the hopper by free-fall and then flow out from the hopper by gravity. First, we verify simulation results by statistical method to ensure the randomness of the filled state of resin pellets in the hopper and validate the simulation method with experiment results. Next, using the simulation method, we clarify that the shape of resin pellets has a great influence on their flowability and find an optimal pellet shape that can improve the flowability of resin pellets from the hopper to the cylinder in the extruder. Finally, we confirm that the optimal resin pellet shape is in dependent of the amount of pellet, kind of material and angle of hopper.

Keywords

• resin pellet
• flowability
• pellet shape
• hopper
• finite element method
• dynamic explicit
• simulation