 Hello friends, I am Satish Arapayani working as an assistant professor in Department of Mechanical Volchian Institute of Technology, Sholapur. Today we are going to discuss on the topic called pressure die casting. Learning outcome. At the end of this session students will be able to understand the pressure die casting which is also in that specifically hot and cold chamber both types. What are the contents covered in this session? First one is interaction, then what is cold chamber die casting, what are the advantages limitations when applications, then hot chamber which is also called as goose neck type, hot chamber also plunger type, and then advantages of hot chamber die casting, limitations of hot die casting, hot chamber die casting. First of all we will have the history. Pressure die casting is believed to have begun sometimes during the middle of 19th century. According to records, Sturges painted the first manually operated pressure die casting machine during 1849. Various compositions of tin and lead were first die casting colors. They are important and the used declined with the development of zinc colloys and then magnesium and copper followed the same. Now pressure die casting is classified into two basically. First one is cold chamber pressure die casting. Second one is hot chamber pressure die casting. The specialty of die casting process lies a metallic mold is used to prepare sand mold with which larger number of castings are made. The metallic mold is known as a die. Cold chamber die casting. The first type we are going to study. In these machines the metal is melted separately in the furnace and transferred to these by means of small ladle, means in cold chamber die casting the metal is melted separately somewhere else and it is brought to near the furnace, it brought near the mold and then it is transferred. After closing the die, the molten metal is forced into the die cavity by hydraulically operated plunger and pressure is maintained till solidification. These machines can either have vertical plunger or horizontal pressure for forcing molten metal into the die upon its application. These machines are widely used for casting a good number of aluminum alloys and brasses. Now we will see what we have told in cold chamber die casting. See this is fixed die half, this is called die with cross section area what is shown. This is called fixed ear and this is movable die half. Now this section is made. Now you can see the ladle. The molten metal is melted somewhere else which is brought near this and then it is poured. One then the molten metal pushes or comes inside this and then with the help of ramp this is been done. This is also called a short chamber you can see from where it is moving you can see. Now we can see here what are the advantages and limitations of this cold chamber die casting. Its construction is simple thus cost of equipment is not very high. Limitations of cold chamber die casting slower cycle time due to the need to transfer the molten metal from the furnace to cold chamber machines hence rate of production will be less. Now as we have seen in cold die casting that die is there and molten metal is brought near it is melted somewhere else and it is brought near the die so the production rate itself will be less. So this is one of the limitations of cold chamber die casting. Applications alloys cast with the cold chamber die castings these are alloys, aluminum alloys specifically alloys is 360, 380, 383, 384, 390, 413 and 518. Alloys with larger proportions of aluminum are also cast specifically Z812 and Z827. Magnesium alloys is at 9 1 D, AM 9 60 A and ES4 1 A. And the copper alloys are also cast with the help of cold chamber die casting. Now we will come to the part hot chamber pressure die casting, hot chamber or pressure die castings are generally classified into two type gooseneck air injection type or submerged plunger type. Now we will come to the first part gooseneck air injection type. In this machine the gooseneck container is operated by lifting mechanism initially it is submerged in the molten metal and filled by gravity then it is raised so as to bring the nozzle in contact with die opening and is locked in that position. This air then forces the metal into the die and pressure is maintained till solidification. When solidification is complete the gooseneck is lowered down and casting is removed by ejector pins after opening the dies. We will see this with the help of the figure now. See these are the operating links in gooseneck this is the burner right this is the fire box this is the metal pot where it has been done and this is the gooseneck. Now with the help of this air you can see this is the stationary die or fixed die here this is movable die these are the electric piece these are the shape of the part which is helping me. Now you can see with the fire box metal pot this has been done then with the help of this this has been flowed here and the part has been done. Now as the shape is gooseneck this is generally called gooseneck air injection type here air is forced we can see how the pressure has been created with the help of air here. It has been created and so that the molten metal flows here and it can be these ejector pins what now once the molten metal comes fills here it has been solidified and with the help of ejector pins this can be with the help of ejector pins this part can be removed or removed right simple in construction now you come to the plunger type. In this machine the gooseneck type container always remains immersed in the metal pot the molten metal from the metal container is forced inside the die with the help of plunger submerged in molten metal and operates hydraulically when plunger moves up the molten metal comes up and fills the cylinder and when the plunger moves down the metal is forced into the die. The movable diaplaton is synchronized such that when the plunger is moving up the movable diaplaton moves away and casting is removed we will see. So plunger type this is hydrotically cylinder operator this is the plunger rod this is again molten metal pool you can see here this is the pot and furnace where it has been made these are the nozzles with the help of which the metal is being put these are die cavity ejector pins and covered die. Now we will see with the help of see when the plunger moves up and down this mechanism causes them to force inside the molten metal and molten metal comes here and solidifies here we are using a plunger type so this is also called as plunger type of hot chamber pressure die casting. Now we will basically remember the two basic differences here in cold chamber the molten metal was melting somewhere else and whereas in this hot chamber whether it is goose neck type of plunger the molten metal is being melted there itself and this source is being used with the help of nozzles to fill the cavity. Now what are the advantages of hot chamber die casting the best advantage one of the greatest advantage associated with the hot chamber die casting is close dimensional tolerances which can be achieved then excellent surface finish on the casting very thin sections can be easily obtained up to 0.75 mm parts ranging from 30 grams to 7 kg can be done and it is also useful for mass production because that one set of die can produce 10000 castings or even more here less flow space is required we are comparing with regular sand casting or something less defects compared to sand casting. We will see in this type a small set up is just required compared to where in sand casting a whole space is required once metal is melted somewhere else castings are produced somewhere else and continuous we are changing the mold or using something else because but that process is suited for even small production but this is generally suited for mass production. What are the limitations associated with this process the limitation associated with this process of hot chamber die casting is cost of equipment and dies very very high initial cost or is very high equipment cost is also high and die cost is also high and it is suitable for non ferrous casting it is not suitable for small scale small scale and also for heavy castings because big size parts when we can say a big machine bed also can be need to be constructed this is not at all suited not at all feasible we can say oxidation of metal in the air injection machine here we can because it is generally more touch in touch with the air so oxidation of metal in the air injection machines is possible diffusion of iron and hard elements into the cast metal in puncher type of machines now think which parts are made from this process in our vehicle our vehicle parts do our manufacture with the help of hot chamber die casting please think which parts can be made references references use are from NPTEL and book PLGEN and some YouTube videos thank you