American Journal of Mechanical and Industrial Engineering 2016; 1(2): 15-19 http://www.sciencepublishinggroup.com/j/ajmie doi: 10.11648/j.ajmie.20160102.12 Plastic Welding: Important Facts and Developments Md Shakibul Haque * , Mohd. Anees Siddiqui Department of Mechanical Engineering, Integral University, Lucknow, INDIA Email address: mshaque26@gmail.com (M. S. Haque) * Corresponding author To cite this article: Md Shakibul Haque, Mohd. Anees Siddiqui. Plastic Welding: Important Facts and Developments. American Journal of Mechanical and Industrial Engineering. Vol. 1, No. 2, 2016, pp. 15-19. doi: 10.11648/j.ajmie.20160102.12 Received: August 24, 2016; Accepted: September 8, 2016; Published: September 22, 2016 Abstract: This paper provides an introduction to some important facts and developments in the plastic welding field for assisting the developments in future in plastic welding. Plastic manufactured part are regularly used in many industries. The parts made of polymeric materials and polymeric composites fulfilled very demanding criteria now-e-days. Plastics have good corrosion resistance, excellent strength to weight ratio and ability to take good finish. Plastics can be categorized as thermosets and thermoplastics. Only the thermoplastic is weld able among these two. A chemical reaction occurs during processing and curing in case of thermo sets resin, that is, as a result of irreversible cross-linking reaction in the mold. Both molded thermosets and vulcanized elastomer components cannot be reshaped by applying heat, because of the irreversible reaction that occurs. And thus in this case joining can be obtained by mechanical fastening and adhesive bonding only. In this paper few selected welding processes are discussed like hot gas welding, friction welding, hot plate welding, etc. Various important Poly Vinyl Chloride welding parameters such as welding techniques, welding temperature, welding speed, equipments requirements have also been discussed. Recent developments in this field are also discussed. Keywords: Poly Vinyl Chloride, P.V.C. Welding, Friction Welding, Hot Air Technique 1. Introduction Plastics are used in day to day life for manufacturing of toys, utensils and complicated part such as heart valve for medical use etc. Plastic parts are frequently used in many industries [2]. Plastics have ability to take good finish, excellent strength to weight ratio and good corrosion resistance. There are two types of plastics, thermosets and thermoplastics out of which only thermoplastic is able to be welded A chemical reaction occurs during processing and curing in case of thermosets resin, that is, as a result of irreversible cross-linking reaction in the mold. [3]. Molded thermosets components cannot be reshaped by applying heat, because of the irreversible reaction that occur [3]. And thus in this case joining can be obtained by mechanical fastening and adhesive bonding only. But, thermoplastics are able to be softened and remolded by means of heating, and can fusion welded. Therefore thermoplastics are able to be welded by following three methods (a) Thermal, (b) Friction (c)Electromagnetic. Further the types of Thermal plastic welding are (a) Hot air technique (b) Hot tool method (c) Laser beam heating (d) Infrared heating. PVC plastics are different from other geomembrane like HDPE, LLDPE, and FPP because it is primarily amorphous while others are semi- crystalline [6]. When PVC is heated it will soften [5, 6], that allow alimited amount of chain entanglements to assure a strong bond. 2. Hot Tool Welding Hot tool welding is a technique in which surfaces to be joined by direct contact with a heated metallic tool. When it is required to join the pipes, the surfaces to be joined are flat hence the tool is a hot plate. However in many applications, such as in automotive rear light and headlamps, because of doubly curved joined interface it require complex tool that allow the hot surface to match the contours of the joint interface. 3. Hot Gas Welding When the external heating method is applied the technique is called hot air technique. In the process of welding the welding rod and a weld groove are simultaneously heated