Manufacturing process

Manufacturing process

1. MANUFACTURING PROCESS

2. MANUFACTURING PROCESS Raw material finished product Classification Shaping process Machining process Joining process Finishing process Property changing process Process

3. 1. Shaping process Process in which shape and size of material is changed without removal of material . Common process :- Casting Forging Drawing Rolling Extruding

4. 2. Machining process Process in which shape and size of material is changed by removing material from unwanted portions of the work piece. Common process:- Surfacing Turning Shaping Drilling Grinding Milling

5. 3. Joining process Process in which two or more parts are joined together. Common process :- Welding Brazing Soldering Bolting Riveting Shrink fitting

6. Moulding and Casting Casting : Process of producing metallic parts of desired shape and size by pouring molten metal into a mould having a cavity and allowing the molten metal to solidify. Moulding: Process of making mould using a pattern. Pattern : Replica or model of the final product. Mould materials : sand, plaster of Paris, metal etc Pattern material : wood, metal, wax, plastic, cement etc

7. Moulding box

8. Classification of Moulding Bench moulding done on a bench Used for small castings Floor moulding moulding done on foundry floor Used for medium and large moldings Pit moulding Moulding done on pits dug on foundry floor. Drag part in pit & separate cope Used for extremely large castings Machine moulding operations such as ramming, pattern removal are done by machines. Faster method used for mass production. Better quality and cost of production less due to mass production.

9. Properties of moulding sand Porosity or permeability Cohesiveness or strength Adhesiveness Plasticity Refractoriness Flowability Chemical stability

10. Sand Casting Sand moulds Moulding box – cope and drag. Gating system – passage for bringing molten metal to mould cavity. It consist of Pouring basin Sprue Gate Core – solid mass of dry sand, having shape of internal cavity or hole in casting.

11. Permanent mould casting Moulds are made of metals (cast iron and alloy steel). Pouring molten metal into the cavity without applying external pressure (gravitational force only). Mould halves are hinged for easy removal of casting. Advantages : Closer dimensional tolerances. Better surface finish. Greater mechanical strength Lower percentage of rejection. Disadvantages : Not suitable for large castings. Cost high Used for mass production only.

12. Die Casting External pressure (pneumatic, hydraulic, mechanical) is employed (pressure die casting) for casting. Fast casting process Metallic mould called Die. Used for lead, Mg, tin, Zinc alloys, Al, copper etc. Types of Die casting Hot chamber Die casting. Cold chamber die casting.

13. Hot chamber die casting A piston is actuated inside the cylinder . Cylinder is having a goose neck at one end. A port is provided near the top of the cylinder to allow molten metal to enter into it. The downward stroke of the piston closes this port and applies pressure on the molten metal. Thus molten metal is forced into the die cavity and solidifies to form a casting.

14. Cold chamber die casting Metal is melted separately and transferred to the cylinder using a hand ladle. After closing the die, the molten metal in the cylinder is forced into the die cavity by applying pressure on the piston. After solidification the die is opened and casting is ejected

15. Advantages of die casting: Very high rate of production Very close dimensional tolerances High surface finish Economical for mass production Intricate shape can be easily cast Thin sections can be casted easily.

16. Disadvantages of die casting All types of alloy cannot be cast Not suitable for large casting High cost of die and die casting equipments. Advantages and disadvantages of die casting equipments No limit of size of parts that can be produced by casting Wide range of materials can be easily cast. Cheapest method for mass production. Intricate shape can be cast. Not economical for few number of castings.

17. Forging Definition : process of changing shape of metals when it is in plastic state, by applying compressive force, is called hot forging or simply forging. Hand Forging Drop Forging Press Forging Machine Forging

18. Upsetting Drawing Down Bending Punching

19. ROLLING Rolling is the process of forming metals into desired shape by passing the metal in between a pair of roller . The two rolls rotated in opposite direction at same speed. The arrangement of rolling for rolling operation is called rolling mill. Example ;bars, plates, sheets, rails Hot rolling ;metal heated above recrystallizition temp Cold rolling ; metal heated below the recrystallizition temp Basis of no: of roller and their arrangements rolling can be classified into ,

20. Two high mill Three high mill Four high mill Cluster mill

21. EXTRUSION Extrusion is the process of forming products of uniform cross sectional shapes in convenient length. It consist of compressing the metal inside a chamber and forcing it out through a die having an opening in the shape of the cross section of the product It can be classified into two Direct Extrusion (Forward Extrusion) Indirect Extrusion ( Backward Extrusion)

22. Direct Extrusion (Forward Extrusion) In this process the metal is placed in the die chamber and it is forced through the die opening by applying pressure on the ram.

23. Indirect Extrusion ( Backward Extrusion) In this case, the extruded part moves out in a direction opposite to that of ram movement. This process requires less fore than direct extrusion process.

24. Welding Welding is the process of joining two metals by the application of heat . Welding is done with the help of a welding machine . Welding are classified into Electrical resistance welding Arc welding Gas welding Thermit welding

25. Electrical resistance welding w/p to be joined are held together and electric current of low voltage and high current is passed through them Voltage: 6 to 10 Volts Current: 60 to 4000 A

26. Seam Welding Flash Welding Butt Welding Spot Welding

27. Arc Welding Surface to be joined are fused by the heat produced from an electric arc. When electrode is kept at a short distance from the work piece, an electric arc is formed in which electrical energy is converted into heat Electrodes are coated with Slag or Flux materials

28. Gas Welding It is a fusion welding in which the required heat is obtained by the combustion of fuel gas A gas flame ( Oxy acetylene flame) is mostly used to produce the welding temperature of the order of 3200 ⁰C

29. Thermit Welding It is a fusion welding process in which the required heat is obtained by an exothermic chemical reaction A mixture of powdered aluminium and iron oxide is placed inside the crusible . This mixture is ignited The resultant products are highly purified iron and aluminium oxide The temperature produced will be above 3500 ⁰C Fe 2 O 3  + 2 Al → 2 Fe + Al 2 O 3

30. BRAZING SOLDERING In case of brazing joining of metal pieces is done with the help of filler metal. Filler metal is melted and distributed by capillary action between the surfaces of the metallic parts being joined. In this case only filler metal melts. There is no melting of workpiece metal. The filler metal (brazing metal) should have the melting point more than 450⁰C. Its melting point should be lesser than the melting point of workpiece metal. Soldering is very much similar to brazing Its principle is same as that of brazing. The major difference lies with the filler metal. The filler metal used in case of soldering should have the melting temperature lower than 450⁰C Strength of soldered joint is much lesser than welded joint and less than a brazed joint.

31. Powder Metallurgy It is the process of pressing fine powdered materials into desired shape and size and heating it in a controlled atmosphere to bond the material. Powder Metallurgy consist of 4 processes Powder Manufacturing Blending Compacting Sintering

32. 1. Powder Manufacturing The most commonly used methods are mechanical methods, atomization, electrolysis etc. Most commonly used powders are copper and iron based materials Particle size ranges from 0.1 microns to several mm.

33. Blending Blending is done to get a homogeneous mixture of powders. A mechanical mixer is used to blend the powders of different materials.

34. Compacting Compacting is the process of converting the loose powder into compact of required size and shape. Powder is poured into the die. The dies are forced together under pressure and it is compressed to desired .size and shape

35. Sintering After compacting the product is heated in a furnaceto a temperature close to the melting point of the base metal. Heating causes the metal particles to sinter. Sintering is done to achieve strength and hardness to the final product.