DESIGN OF A PLASTIC WASTE RECYCLING EXTRUDER

ABSTRACT

This report covers a detailed design solution of an extruder that is meant to be used on recycled plastic waste. However, due to readily available extruders that can process only recycled plastics, this report went further as to design an extruder that could accommodate not only plastics but rather composites which were a mixture of plastic waste with aggregates such as sawdust and sand. We had to ensure the design was not only efficient but also cost effective. This implied that we had to ensure the extruder could be locally fabricated without compromising its quality and integrity.

The research done on the project coupled with theoretical formulae guided the design process of the extruder. The design methodology used in this project followed 5 basic steps which included understanding the user’s need which helped us generate a product concept. We then defined the functional requirements of the extruder and hence came us with concept designs. The concept design provided us with preliminary sketches and drawings. Finally, we developed a detailed design solution for the extruder.

During the detailed design solution, we performed material selection for each component of the extruder. Then, breaking the design of the extruder into four (4) crucial component systems namely; Power system, feeding system, extrusion system and heating system, we started our calculations by determining the motor that would deliver the appropriate extruder output. We then analyzed flow in the extruder i.e. output and input, whose values allowed us to determine the type and size of feeding system (bin and hopper) we required. We then researched on the most applicable heating system for our extruder. Finally, the entire design and respective simulations were done using CAD software (SolidWorks 2017).

Once the design was completed, we performed a material market availability and cost analysis which helped us to determine the cost of the designed extruder. With the help of KIRDI, we were able to cost our extruder to approximately Ksh. 1,230,0000.00/-. This cost was a much cheaper alternative compared to existing extruder designs which cost from at least Ksh. 5 Million. Therefore, for such a reasonable cost and the ability of this extruder  design to accommodate composites, this design was a preferable option.