3. It is the oldest known primary and principal manufacturing processes. It involves, prepared and allowed to solidifyon of cavity to resemble closely the required final product. Liquid moltel metal is poured in to the cavity and allowed to solidify. After solidification, the product removed from the mould. Other casting processes are Shell mould casting Precision investment casting Plaster mould casting Die casting, etc.,

4.  It is a solid state manufacturing process involving minimum material wastage and high production rate. In this process, metal may be heated to slightly below the solidus temperature and large force is applied, such that the material flows and takes the desired shape.  Normally used for large scale of production. Metal forming processes Rolling Drop forging Press forging Extrusion wiredrawing., etc.,

5.  It is secondary manufacturing processes, where raw materials are processed through the casting or forming processes. It involves joining pieces either permanently or temporarily to perform the necessary action. The joining can be done by heat or perssure or both. Most of the steel structural constructions are first rolled and then joined together by a fabrication processes.  Types of fabrication processes  Gas Welding  Electric Resistance welding  Electric arc welding  Thermit welding  Cold welding  Brazing  soldering

6. It is also a secondary manufacturing process. In this additional unwanted material is removed in the form of chips from the blank material by a harder tool to obtain the desired shape. It is normally the most expensive compared to other processes because more energy is consumed and also a lot of waste material generated. Still widely used because of its good dimensional accuracy and good surface finish. Types of machining processes Turning Drilling Shaping and planning Milling Grinding Broaching sawing

7. Unit 1 Steps involved in making a casting – advantages of casting and its applications – patterns and pattern making – types of patterns – materials used for patterns, pattern allowances and their construction – principles of gating – gating ratio and design of gating systems

9. Flask : A moulding flask is one which holds the sand mould intact. Depending up the position of the flask in the mould structure it is referred to by various names such as drag - lower moulding flask; Cope – upper moulding flask and cheek – intermediate moulding flask used in three piece moulding. It is made up of wood for temporary application and more generally of metal for long- term use. Pattern : Pattern is a replica of the final object to be made with some modification. The mould cavity is made with the help of the pattern. Parting line : this is dividing line between the two moulding flasks that makes up the sand mould. Bottom Board : this is a board normally made of wood which is used at the start of the mould making. The pattern is first kept on the bottom board, sand is sprinkled on it and then the ramming is done in the drag.

10. Facing Sand : The small amount of carbonaceous material sprinkled on the inner surface of the moulding cavity to give a better surface finish to the castings. Moulding Sand : It is freshly prepared refractory material used for making the mould cavity. It is a mixture of silica, clay and moisture in appropriate proportions to get the desired results and it surrounds the pattern while making the mould. Backing Sand : It is what constitutes most of the refractory material found in the mould. This is made up of used and burnt sand. Core : It is used for making hollow cavities in castings. Pouring Basin : A small shaped cavity at the top of the mould into which molten metal is poured. Sprue : The passage through which the molten metal from the pouring basin reaches the mould cavity. In many cases it controls the flow o metal into the mould. Runner : The passageways in the parting plane through which molten metal flow is regulated before they reach the mould cavity. Gate : The actual entry point through which molten metal enters mould cavity.

11. Chaplet : Chaplets are used to support cores inside the mould cavity to take care of its weight and overcome the metallostatic forces. Chill : Chills are metallic objects which are placed in the mould to increase the cooling rate of castings to provide uniform or desired cooling rate. Riser : It is a reservoir of molten metal provided in the casting so that hot metal can flow back into the mould cavity when there is a reduction in volume of metal due to solidification.

12. Complicated shapes, intricate shapes and very thin sections can be casted as molten metal flows into the mould cavity. Ferrous or non-ferrous materials, any thing can be casted. Tools required are very simple and inexpensive. Ideal method of manufacturing for small scale production. If casting cooled uniformly, it do not have any directional properties. Any size and weight up to 200tons can be made. Pipe fittings, valves, levers, couplings and differential housings etc., are made of malleable cast iron. Critical machine parts like crankshafts, gears, valves, pump casings, paper mill rollers, which are nodular cast iron. Valves, turbine parts, chemical resisting vessels, impellers which are made of high alloy steel. Medium/heavy bearings, artistic castings, propellers – are made of gun metal. Lathe beds, machine foundations, water pipes, cyclinder blocks, brake drums etc,. Made of gray cast iron.

13. A pattern may be defined as a model or form along sand is packed to give rise a cavity known as “MOULD CAVITY” and the molten metal is poured into it and allowed for solidification. The obtained product is called as CASTING/ CAST / CAST OBJECT. Pattern is a mould forming tool. It is a model or replica of the final object that has to be casted. Pattern is essential even if one cast is required and is always bigger in size compared to the final product.

14. A casting is smaller in size compared to its pattern, because of the various allowances. In some cases patterns may not have holes or slots even if the final casting may require a hole or a slot. A pattern may be an assembly of 2 or 3 parts, even though the final casting is a single piece. A pattern and the casting may not be of the same material. To create a mould cavity. It enables creation of core prints. It makes provision for runner, gates and risers. Patterns properly made and having smooth surfaces reduce casting defeats. A properly constructed pattern minimizes the overall cost of the casting.

15. Selection of material for pattern depends up on the functions and criteria. Number of castings Depending on the moulding process (sand moulding, shell moulding etc.,) Type of surface finish required. Moulding method (Hand moulding or machine moulding) Shape, size, cost (easy shape & joining if required, light weight, low cost Casting design Moulding material used (corrosion and chemical reactions between the mould and pattern materials). Dimensionally stable and unaffected by variations in temperature and humidity.

16. Wood, metals and alloys, plaster of paris, plastic, rubbers, wax and resins. Wood : Inexpensive, easily machinable, ease of assembly, availability of raw material, lighter, good surface finish and easily repairable. Limitations of wood: Repeated use can alter the edimensions of the pattern due to shrinkage, swelling, etc., Poor wear resistance. Need smooth handling. Weak compared to other pattern materials like metals.

17. Metals: Aluminium, steel, brass, cast iron, white metal. Good for mass production. Good surface finish. Durability. Ceramics: Able to withstand high temperatures. Excellent surface finish. Plaster of paris: employed to achieve complex shapes. Wax: single time usage, low cost, recyclable.

18. Types of allowances: selection of correct allowances reduces costs and avoid rejections. Shrinkage or contraction allowances Liquid allowance Solid allowance Draft or taper allowance Machining or finish allowance Distortion or camber allowance Rapping allowance

19. Shrinkage or contraction allowances (except Bismuth) Almost all the metals/alloys shrink or contract volumetrically after solidification, therefore the pattern to be obtained when compared to final shape, should be amplified in all directions. LIQUID shrinkage: refers to reduction in volume when the metal changes from liquid to solid state at the solidus temperature. SOLID shrinkage: refers to the reduction in volume caused, when metal loses temperature in solid state.

20. External Surface Draft Allowance: 10 – 25mm per meter Internal Surface Draft Allowance: 45 – 65 mm per meter

22. One piece pattern or single piece pattern Split pattern or two piece pattern Loose piece pattern Match plate pattern Cope and drag pattern sweep pattern Gated pattern Skelton pattern

23. Used for jobs which are very simple and made up of single piece of pattern. This type is employed where the pattern can be easily removed from the mould. It contains only DRAG. One of the surfaces is usually flat and used as parting line.

24. Employed when it is difficult to withdraw casting from the mould. If the depth of the casting is too high. It splits along the parting surface. One half of the pattern is moulded in drag and the other half in the cope. The two halves of the pattern must be aligned properly by making use of the dowel pins.

25. This kind of patterns are used to create a mould with obstacles while removing the pattern from the mould. They have a loose piece for easy withdrawal of pattern from the mould. Moulding with loose piece is highly skilled and expensive.

26. In this kind of pattern, one half of the pattern is clamped to one-side of the match plate and the other half to the other side of the plate to prepare the mould. Later the match plate will be removed. Material for the this pattern is METAL. Gates and runners are also attached to the match plate. Generally employed for mass production of small casting with higher dimensional accuracy. Even though the construction cost is high, it can be compensated with high production rate and greater dimensional accuracy.

28. Used for mass productions of small castings. Gates are provided to each component, but the sprue and the runner are common. Saves moulding time.

29. It is a 2-dimensional pattern. Used only for casting which are symmetrical and regular in shape like cylinder or pipe. A simple sweep is rotated about the central axis to produce a mould cavity. It saves time to prepare the pattern and mould.

30. Generally employed for huge casting or hollow casting. When pattern require lot of material we use this kind, we prepare it as hollow. Used for big castings. It is similar to split pattern, where in the case of split patter or any other type of pattern gating system (runner and ingates) designed in the drag box. In Cope and drag pattern gating system will be designed in both the cope and drag. It will be huge and cannot be handled by one person. So, cope part and drag part are moulded separately and assembled.

31. It refers to all the passages through which the molten metal flows is called as Gating System. Includes pouring cup, sprue, raiser, runner and gate. Mould should be filled in the shortest time possible with out having to raise the temperature. Molten metal should flow with out any turbulence and air. Slag and other waste material should not enter into mould. Metal flow should be maintained such that no gating or mould erosion takes place. Make sure that the molten metal reaches the mould cavity completely. The gating system should be economical and easy to implement and remove after casting solidification. Finally casting yield should be maximised.

32. Pouring Basin Sprue Sprue Base Well Runner Ingate Riser

33. Molten metal is not poured into the mould cavity directly, so as to avoid mould erosion. Pouring basing holds back the slag and dirt entering in to the mould cavity. Through the sprue, the metal is brought into the parting plane. Metal needs to gain velocity while passing through the sprue, so the cross-section of the sprue should be taper and also the prevent air.

34. It is the reservoir for metal at ht bottom of sprue. It reduces the momentum of the metal. Velocity gained in the sprue is reduced partially – reduces erosion. Changes the direction of the metal to the runners.

35. Runner is located in the horizontal plane, connecting the sprue to the gates. These are in trapezoidal cross-section. The amount of metal flowing through the runner should be always full to trap the slag and dirt entering in to the mould cavity.

36. Design of Runner and gates depends on the type of Gating System  Pressurized Gating System: The total cross-sectional area gradually decrease from the choke to ingates.  Un-Pressurized Gating System: The total cross-sectional area gradually increased from choke to ingates. Pressurized Gating System A C : A R : A G = 1 : 1.3 : 1.1 (For Gray Cast Iron) A C : A R : A G = 1 : 2 : 1 (For Aluminium) A C : A R : A G = 1 : 2 : 1.5 (For Steel) Un – Pressurized Gating System A C : A R : A G = 1 : 4 : 4 (For Gray Cast Iron) A C : A R : A G = 1 : 3 : 3 (For Aluminium) A C : A R : A G = 1 : 3 : 3 (For Steel) A C – Choke Area; A R – C/S Area of Runner; A G - Total C/S Area of the ingates.

37. Pressurized Gating SystemUn-Pressurized Gating System Total cross sectional area decreases towards the mould cavity Total cross sectional area increases towards the mould cavity More turbulence and chances of mould erosion Less turbulence Flow of liquid metal is almost equal from all ingates Different from each ingates Casting yield is moreCasting yield is less Complex and thin sections can be successfully cast Difficult to cast complex and thin sections

38. Multiple ingates are often [referable for large castings. A fillet should be used where an ingate meets a casting – produces less turbulence. The minimum ingate length should be three to five times the ingates width, depending on the metal being cast. Curved ingates should be avoided, as far as possible. Top Gate or Drop Gate Bottom Gate Parting line side gate.

39. Top GateBottom Gate Parting line Gate