 Hello friends, myself Dr. N. S. Kartikar, Assistant Professor, Department of Mechanical Engineering Valachandra Institute of Technology, Solapur. Now we are going to see the particular description, discussion on welding of plastic part 1. At the end of this session, the student will be able to understand the need and importance of welding of plastics. Student will be able to apply welding techniques in real time. The content for our presentation as follows. Initially introduction, then we will see the need of welding of plastics, classification of plastic welding, external heating category, one of the type hot tool welding. In the introduction, let us see the few of the points related to the plastic. Initially, let us see the introduction about the plastic material, their properties and the manufacturing things about the plastic. The plastic material, as we know, the advanced job material, which nowadays use for almost in every areas of application. The technical parts, the domestic parts are nowadays using the plastic material for the particularly manufacturing of the various parts. The need of plastic material products that depend on the particular fulfillment of that parts working in the respective environment. The plastic material is going to be used because of the many advantages of the plastic material like that can be easily moldable, those are carrying the bad conductor of electricity, those are having the non-magnetic properties, those shows the non-corrosive properties and so many advantages properties are there because of which the plastic material is favorably used for the part manufacturing. When we are thinking about the plastic part manufacturing, there are different particularly categories of the same like the part can be produced, the product is going to be used as a single part. That means a single part is self-sufficient for the requirement of particular need. Many a times it is not the case and we need to go with the assembly. Many separate plastic material parts are required to be assembled together. The need of welding of plastics as we see over here for assembly purpose, for repair and maintenance purpose, for packaging, many a times we require the dissimilar materials joining of plastic parts. In that case also the welding of plastic is required over there. Many a times it is required to fulfill the need of situation and force to go with the welding of plastics. When we talk about the assembly of plastic elements, in that case the joining of plastic consists the various methods like mechanical joining. That means we can go with the particularly fasteners, nut, bolt, screws, rivets, pins, etc. In second case adhesives bonding that means various adhesives can be used for joining the two dissimilar plastic parts. The third one which we are going to see in detail for one of the type that is welding. At this stage of this session, let us I am going to ask one question to you. Are you able to recall or share some of the applications of welding of plastic joints which you had used or seen earlier anywhere in real time? Just think and enlist, yes. I hope that you had enlisted the various products where you found there is a need of plastic welding. Now let us go with the classification of plastics welding processes. Welding processes are categorized by the heating method that is used. The two general categories are external heating and internal heating. The particularly heating method has classified in these two ways, external heating. What exactly the external heating means? It rely on convection and conduction to heat the weld surface. For example, hot tool, hot gas, extrusion, implant induction, implant resistance welding are some of the processes of the examples of external heating welding processes used for plastics. The second category internal heating, it really on conversion of mechanical energy into heat through the surface friction. That means there is no any direct application of heat energy by convection or conduction as such. Further, it is divided into internal mechanical, internal electromagnetic heating, ultrasonic, friction, laser welding and so on. There are such kind of subtypes for the internal heating welding processes for the plastics. We will see one of the subtypes that is hot plate welding. It is the simplest of the mass production technique to join the plastics. A heated plate is clamped between the surfaces to be joined until they soften. The plate is then withdrawn and the surfaces are brought together again under controlled pressure for the specific period. The fused surfaces are allowed to cool forming a joint. The tool is often coated with the non-stick material for example, Teflon to act as a release agent. Likewise, the hot plate welding process will go on. Hot plate welding includes two kinds, high temperature hot plate welding, non-contact hot plate welding. Let us see the high temperature hot plate welding. The tool is used, let us see, high temperature hot plate welding. The tool is not coated with the release agent. The tool is heated to 300 to 400 degrees Celsius. Once the parts are disengaged for the tool, any residual material is either oxidized away or mechanically removed. In six stages, you can visualize how the part can be welded easily. Now, this is the look at to the cursor. This is the first stage. Hot plate welding, let us see. Six stages are there, parts are hold and allowed for particularly further in contact with the heating platen. Now the parts are fixed into the particular holding fixture. These are the fixtures in which the blue color job is there. In the second stage, the heating platen is heated and inserted in between the particularly two parts which are seen over here in blue color which are further held into the fixtures. In the third stage, parts are pressed against the platen to get the particularly heating up the surfaces of the job. It is allowed in this particular situation for specific period of time. Now in the next step, you can see over here the fixtures are going to be going away from each other. The heated platen is removed back and in the next stage, parts are compressed to the edges to each other so that the particularly edges are weld together. After specific period of time, you can see over here the holding fixtures are unloaded and the completed part can be uploaded. So in these six stages, you can very easily understood how the heating platen are in contact with the separated two singular elements under pressure. Further removal of heated platen, further the pressure is applied for particularly edges which are previously softened and after a specific period of time, the job is ready for particular application. Hot plate welding includes two kinds, high temperature hot plate welding and non-contact hot plate welding. Non-contact hot plate welding, the parts to be welded are brought near to the tool 1 to 3 mm and convection and radiation heating from the tools heats the welding surfaces. Hot plate welding will see the advantages, limitations and applications of the hot plate welding. Advantages, geometry, flexibility for product, manufacturing feasibility for discrete parts for assembly product etc. One major limitation to hot plate welding is the cycle time. A typical cycle time is 30 to 0 seconds and larger with the larger parts it can be as long as 30 minutes also. Applications, some of the applications, polyethylene pipe welding for gas line installation, fuel tank assemblies for the automotive industries, packaging the products and many more. References for these particular presentations are as follows. Thank you.