Creating and Building a Laboratory Extrusion Machine for Polyvinyl Chloride (PVC) Pipe Design and Fabrication

0
220
You can download this material now from our portal

Creating and Building a Laboratory Extrusion Machine for Polyvinyl Chloride (PVC) Pipe Design and Fabrication.

Abstract:

The Mechanical Engineering Laboratory at the Federal University of Minna, Nigeria, requires an extrusion machine to facilitate the teaching and learning of PVC extrusion processes. Currently, there is a scarcity of extrusion machines used for teaching, which hinders the bridge between engineering graduates in the industry and student learning at the university. To address this issue, a laboratory PVC extrusion machine was designed and fabricated to produce thermoplastic pipes. The machine operates by forcing PVC melt resin through an annular die to create PVC pipes, which find applications in various household uses such as portable water sewage and electrical conduit systems. The design of the extrusion machine involved the selection of specific drives, feeding systems, and control mechanisms.

The chosen drives included spur gears, screw shaft, thrust bearings, and an electric motor, resulting in a required power of 6.93 kW with a power scale-up factor of 0.122 and a gearing ratio of 2:1. The feeding system consists of a cylindrical barrel with a diameter of 770mm and a hopper equipped with an electrical control switch for operational control. The machine was analytically designed and modeled using Pro-Engineer software before its physical fabrication.

The extruder’s design employed a compression ratio of 8:1, with an extruder length of 1120 mm. The maximum shear stress for the extruder design was determined to be 17.1 kN/m^2, and the extrusion pressure was measured at 7.7 MN/m^2. The design extruder circumference speed was set at 1.2 m/s, with a plastic flow rate of 1 m/s. Additionally, the velocity drop at the die inlet was calculated to be 0.1 m/s, while the drag or volumetric flow rate of the PVC melt from the extruder was determined to be 0.0009 m^3/s. The mass flow rate of the PVC melt was estimated to be 7.9 kg/s, and the produced pipe had a diameter of 40mm.

However, the lack of an automated temperature controller system in the machine resulted in the pipe having a bent structure. To address this issue, a sliding plate was introduced to prevent deformation due to the pipe’s weight. The machine’s efficiency was found to be 51%, and it was constructed using locally sourced materials. The utilization of this machine for practicing PVC extrusion processes is expected to significantly enhance students’ understanding and knowledge of the extrusion process.

Creating and Building a Laboratory Extrusion Machine for Polyvinyl Chloride (PVC) Pipe Design and Fabrication.

Leave a Reply