Design and construction of a fibre cutter to produce new grades of automotive composites

Abstract

This project involves the design and construction of a fibre cutter which can be used to chop different types of fibres in order to produce alternative composite materials. Chopped fibre is needed in the production of composite materials for the automotive industry and other sectors. Bulk Moulding Compound (BMC) and Sheet Moulding Compound (SMC) are the most commonly used processes. The process uses chopped glass fibre to produce light composite materials. Currently, the market offers many alternatives to quickly cut glass fibre. However, these methods cannot be used with alternative fibres which are more difficult to handle, so a new fibre cutter is needed to cut alternative fibres and produce new materials which can offer lighter, and more sustainable reinforcement alternatives than glass fibre. The chosen solution has been the modification of an existing fibreglass chopper gun, which was able to cut glass fibre at different lengths with its cutting wheels, but could not cut other types of fibres. After the adaption of the conceptual design to the existing chopper gun, the gun arrangement was able to cut carbon fibre successfully, and is also capable of cutting some types of coated rayon fibre. In order to prove the usefulness of this new design, the chopper gun has been used to cut carbon fibre to produce alternative BMC materials, where, remarkably, that the cutting process just needed 72 seconds to produce 475 grams of chopped carbon fibre. These alternative BMC materials have been tested and compared with conventional glass fibre BMC compounds, demonstrating superior mechanical properties and lower density.