 Hello friends, myself Professor Narendra Kartikar, Assistant Professor, Department of Mechanical Engineering, Valachandra Institute of Technology, Solapur. Today, I am going to present the particular topic, rotational molding. The learning outcome for this presentation. At the end of this session, student will be able to understood the process and its application regarding plastic rotational molding process. The presentation contents are as follows, the flow of the presentation goes likewise, introduction plastic rotational molding process, polymers commonly used for rotational molding, advantages for the rotational molding, disadvantages for the rotational molding. And at the end of this session, we will see the applications, both technical and domestic with the means of rotational molding. In the introduction, let us see the various points for the discussion. Plastic material need of plastic material products, plastic part manufacturing. As you aware, almost for many technical as well as domestic part products, material has been now shifted or transferred to the advanced materials that is about the plastic material. Due to the enormous advantages of plastic material properties, we are shifting from general materials, metals alloys to the non-metal that is plastic. Many of the advantages properties of the plastic will serve the need of plastic material products. In real time of environment, plastic delivers the very important advantage like easily moldable and many other times easily remoldable recycle also. The weight to the strength ratio as well as transparency to the opaqueness kind of many advantages are there for the plastic. Now, the plastic is the raw material which has to be further processed to produce the plastic part manufacturing. According to the specifications of the plastic part, there are number of processing methods all developed considering the size, shape, geometry, thickness, cost, color and many other aesthetic views. The plastic part is considered for the particular plastic part manufacturing process. As far as this presentation is concerned, we are going to discuss the plastic rotational molding process. Normally, this process we are going to discuss which is carried out in a four stages. Now, the diagram shows the four stages charging, heating, cooling and demolding. Now, the particularly rotational molding process setup is somewhat moderate to large size. In the first stage, you can see that the first diagram, the lower half is open one and which is filled through the means of plastic powder. The plastic powder is filled into that container and then further upper half of the mold is covered on the same that you can observe in the sub diagram B. Diagram A is charging, sub diagram B is heating. Now, after fulfilling and ensuring the thorough compact clamping of these two distinct halves, the total mold is going to be rotated about their respective rotational axis. That can be rotated in one axis, about one axis, about two axis and so many more. As per our referred diagram, the molds are rotated in the two directions rather two axis as well as while in a rotary condition, it is also carried out with the heating process. Due to the heating, the material filled into the same which is earlier in powder form now converted into the plastic state. The plastic state, the molten state plastic material is now tried to adhere the inner wall of the mold. Due to the rotary motion specified RPM rotary motion, the plastic raw material is going to be uniformly distributed and adhering the inner walls of the mold. The process is continued with the specific period of time as per the calculations of quantity is fitted as well as the general overall size specifications. After that particular period of time, then the heating process is cut down, thorough little bit rotary motion is allowed under the cooling operation. This stage the cooling process is carried out, rotary motion is still continued, but the cooling is going to be carried out with the natural air, cooled cold water and so on. After a specific period of time, we can ensure that thorough solidification of particularly plastic raw material is there. Then the process of cooling is cut down, obviously to taking out of the part from the mold we have to remove the upper half of the mold and demolding is carried out. Thus in a 4 stages the large uniform symmetric jobs are carried out through the means of plastic rotational molding process. We will see the one more image in real time that how the setup look alike. You can observe to the right side the big cylinder is there which consists the heating as well as particularly cooling arrangement. The four distinct molds you can observe connected to the main shaft which is always in a rotary condition and the left hand side you can observe the rotary mechanism which controls the speed and further specifications. The molds you can observe over here of four number are going to be used to produce the particular part, can you identify the same. Now the polymers commonly used for rotational molding processes are as follows, some of these are polypropylene, polyethylene and so many more. Advantages of rotational molding, it is a fast production, heavy size part manufacturing is easily possible, low cost in mass production, color flexibility is there, low labor cost and low waste will be there. Little disadvantage for the rotational molding, very high initial tooling cost, setup cost and only hollow part designs can be forwarded for rotational molding. Now application of rotational molding, at this stage of this session are you able to share some of the day to day application of plastic rotational molding process? Just think about an end list. Now I will share some of the applications. I think many other times you have seen the overhead water storage tanks, big tanks those are only can be produced through the means of rotational molding. Some decorative large hollow parts can be also produced through the rotational molding. Storage containers are also another application of rotational molding. References for this presentation NPTEL website, Wikipedia website and modern plastic handbook. Thank you.