 What is Casting? Casting is a process of reducing metal or alloy parts by pouring molten metal or alloy into a prepared mould and then allowing the metal or alloy to get solidified. Well, this is a process so it has to have its own advantages, right? So what are the advantages of metal casting? Casting can be used to produce complex, un-economical shapes which are difficult to produce by other processes. A permanent operating casting is one piece and hence no metal drying processes are needed. Very heavy parts that are normally difficult to fabricate can be easily manufactured by casting. Casting produces machinable parts. Casting can be easily mechanized using machines for mass production of machine parts, applications for metal casting, transportation vehicles, automobile engine parts and railing and crossings. These are some of the many examples that make use of metal casting. Now, a pattern is defined as a model or a replica of an object to be cast. The type of pattern to be used for a vertical casting depends upon the quantity of casting to be produced, its size and shape of casting, type of moulding method, design of casting, the various types of patterns which are commonly used are single or solid pattern, two visor spit pattern, loose piece pattern, open dag pattern, gated pattern, match plate pattern, sweep pattern, skeleton pattern, segmental pattern, floorboard pattern, agged up pattern, etc. When a pattern is removed, a cavity corresponding to the shape of the pattern remains in the sand which is known as mould or mould cavity. This sand is known as moulding sand and is used mainly because of its low cost. While low cost, because the sand is normally sourced from riverbeds, lakes, sea and deserts, you know, nature. Mould cavities can also be manufactured using shell moulding and CO2 moulding. Sand moulding consists of a sand-racing dumped over a heated pattern which results in the formation of shell over the pattern. The shell is then stripped and joined together to mold. It has a high surface finish and is used for areas where greater accuracy and smooth surface finish is unheated. Second, there is CO2 moulding. CO2 gas at a pressure of about 1.5 kg per cm where it is diffused to the mixture of pure dry silica sand to initiate hardening reaction. The cost of raw material is low and production rate is high and are hence used for steel iron aluminium and copper based alloy casting. So, the question arises, what are the three normally used casting processes? Well, the first is pressurized casting in which metal is poured by pressure into metal, where the metal solidifies under pressure with rates of surface finish. This method has high production rates and is hence used to manufacture automobile parts, toys, decorative parts etc. Second comes centrifugal casting. Here several cavities are located around the outer edge of the world and the metal is fed by radial gates at the center. These castings are near perfect with low rates of rich action. Third and the last casting process is vacuum casting. A mixture of fine sand and UD3 is moulded over a metal-dyed robotic arm and immersed partially in a furnace. This produces low pressure in the mould which draws the metal inwards. The temperature of the mould metal is generally 55 degrees Celsius above liquid temperature and hence it quickly solidifies. Advantage is included in the greatest strength and highly mechanizable process. Normally, a pattern is always made larger than the final casting because it carries certain allowances due to metallurgy and mechanical reasons. Some of them are shrinkage allowances which is provided to compensate for thermal contraction, machining allowance which is the amount of dimensional casting which may require machining all over or on certain specified portions. Draft allowances are given to all vertical faces of a pattern for their easy removal from sand after allowance comes the gating system which is a term applied to all channels by which molten metal is delivered to the mould cavity. It consists of pouring cups and sprues, runner, gates etc. A riser is a passage of sand made in the cope to permit the molten metal to rise above the highest spot in the casting. It also allows extra gases to escape. Next in line are casting defects and their remedies. Caused due to a single manufacturing fault or a combination of many. The first in the list are globules caused due to excess moisture in the mould and sand and can hence be controlled by regulating moisture. Second is porosity which occurs due to the presence of gas in metal and can be controlled by regulating pouring temperature. Third shrinkage is caused by faulty gating, faulty rising, very improper chilling and can be remedied by ensuring proper solidification. Fourth comes inclusions which are again caused due to faulty gating system and can be remedied by modifying the same. Last comes hot years of hot cracks which are caused due to the lack of core or mould collapse feasibility and can be remedied by improving the core and mould collapse feasibility. The final part is the inspection of casting which is done so as to detect any defect in them. First is the destructive method where samples of castings have been cut into pieces at points where defects are suspected. But this leaves a lot of chance as a sample may or may not contain a defect which is present in a lot of other samples. Second comes non-destructive methods which include visual inspection using microscores magnifying glass not beneath your eye. Inspection for dimensional accuracy as it reveals whether the pattern or the core box is used or not. Second test with a timer resulting in some switch is noted. This is cross-chictor distantly within the mass of casting. One of this ensures for a perfect metal casting process which in turn gives you a lot of your daily products like, well, pretty much everything. Thanks for watching. It's time for this episode's question. What do you mean by casting process simulation? In the next episode of Mechanical Engineering Insiders, why not what forming process are? So like, subscribe and comment with your feedback to help us make better videos. Thanks for watching.