SUBJECT

1. SUBJECT MANUFACTURING TECHNOLOGY Prepared by- Amit Kumar Guest Lecturer GovtPolytechnic Manesar Automobile Engg. Deprtment

2. CONTENTS Drilling Boring Milling Grinding Finishing Operations

3. Drilling Drilling is the operation of producing circular hole in the work-piece by using a rotating cutter called DRILL. The machine used for drilling is called drilling machine. The drilling operation can also be accomplished in lathe, in which the drill is held in tailstock and the work is held by the chuck. The most common drill used is the twist drill.

4. Drilling Machine It is the simplest and accurate machine used in production shop. The work piece is held stationary ie. Clamped in position and the drill rotates to make a hole. Types :- a) Based on construction: Portable, Sensitive,Radial, up-right, Gang, Multi-spindle b)Based on Feed: Hand and Power driven

5. Sensitive Drilling Machine Drill holes from 1.5 to 15mm Operator senses the cutting action so sensitive drilling machine

6. Radial Drilling Machine It the largest and most versatile used fro drilling medium to large and heavy work pieces.

7. Up-Right Drilling Machine Drill holes upto 50mm Table can move vertically and radially

8. Gang type drilling machine In gang drilling machine, a number of single spindle drilling machine columns are placed side by side on a common base and have a common worktable. A series of operation may be performed on the job by shifting the work from one position to the other on the worktable. a number (2 to 6) of spindles with drills (of same or different size) in a row are made to produce number of holes progressively or simultaneously

9. Drill Materials The two most common types are 1. HSS drill - Low cost 2. Carbide- tipped drills - high production and in CNC machines Other types are Solid Carbide drill, TiN coated drills, carbide coated masonry drills, parabolic drills, split point drill

10. Tool Nomenclature

11. Drilling operations… • Operations that can be performed in a drillin g machine are • Drilling • Reaming • Boring • Counter boring • Countersinking • Tapping

12. Operations in drilling machine

13. BORING Boring is a process of producing circular internal profiles on a hole made by drilling or another process. It uses single point cutting tool called a boring bar. The boring bar can be rotated, or the work part can be rotated. Machine tools which rotate the boring bar against a stationary work piece are called boring machines (also boring mills).

14. Boring Machines 1.Horizontal boring machine :- A horizontal boring machine or horizontal boring mill is a machine tool which bores holes in a horizontal direction. There are three main types — table, planer and floor. The table type is the most common and, as it is the most versatile, it is also known as the universal type. Used for drilling ,boring, and milling operations.

15. Vertical boring machine A large type of boring machine in which a rotating work piece is fastened to a horizontal table, which resembles a four-jaw independent chuck with extra radial T slots, and the tool has a traverse motion. Cutting tools are stationary except for feed movements.

16. MILLING Milling is the machining process of using rotary cutters to remove material from a workpiece advancing (or feeding) in a direction at an angle with the axis of the tool. It covers a wide variety of different operations and machines,on scales from small individual parts to large,heavy-duty gang milling operations. It is one of the most commonly used processes in industry and machine shops today for machining partsto precise sizes and shapes.

17. PRINCIPLE OF MILLINGMACHINE Milling operates on the principle of rotary motion. A milling cutter is spun about an axis while a workpiece is advanced through it in such a way that the blades of the cutter are able to shave chips of material with each pass.

18. Variety of Operations Face milling End milling Keyway cutting Dovetail cutting T-slot and circular slot cutting Gear cutting Drilling Boring Jig boring

19. HORIZONTAL MILLING MACHINE Horizontal milling machine. 1: base 2: column 3: knee 4 & 5: table (x-axis slide is integral) 6: overarm 7: arbor (attached to spindle) A horizontal mill has the same sort of x–y table, but the cutters are mounted on a horizontal arbor across the table. Many horizontal mills also feature a built-in rotary table that allows milling at various angles; this feature is called a universal table.

20. VERTICAL MILLING MACHINE Vertical milling machine. 1: milling cutter 2:spindle 3: top slide or overarm 4: column 5:table 6: Y-axis slide 7: knee 8: base In the vertical mill the spindle axis is vertically oriented. Milling cutters are held in the spindle and rotate on its axis. The spindle can generally be extended (or the table can be raised/lowered, giving the same effect), allowing plunge cuts and drilling. There are two subcategories of vertical mills: the bed mill and the turret mill.

21. GRINDING Grinding is a process of removing material by abrasive action of a revolving wheel on the surface of a work-piece in order to bring it to required shape and size. The wheel used for performing the grinding operation is known as grinding wheel It consists of sharp crystal called abrasive held together by a binding material or bond The wheel may be a single piece or solid type or may be composed of several segments of abrasive blocks joined together.

22. DIFFERENT METHODS OF GRINDING… SURFACE GRINDING Surface grinding uses a rotating abrasive wheel to remove material, creating a flat surface. The surface grinder is composed of an abrasive wheel, a work holding device known as a chuck, either electromagnetic or vacuum, and a reciprocating table. Grinding is commonly used on cast iron and various types of steel. These materials lend themselves to grinding because they can be held by the magnetic chuck commonly used on grinding machines, and they do not melt into the wheel, clogging it and preventing it from cutting.

23. CYLINDRICAL GRINDING Cylindrical grinding (also called centre-type grinding) is used to grind the cylindrical surfaces and shoulders of the work piece. The work piece is mounted on centres and rotated by a device known as a drive dog or centre driver. The abrasive wheel and the work piece are rotated by separate motors and at different speeds. The table can be adjusted to produce tapers. The wheel head can be swivelled. The five types of cylindrical grinding are: outside diameter (OD) grinding, inside diameter (ID) grinding, plunge grinding, creep feed grinding, and centre-less grinding.

24. ELECTROCHEMICAL GRINDING… Electrochemical grinding is a type of grinding in which a positively charged work piece in a conductive fluid is eroded by a negatively charged grinding wheel. Electrolytic in-process dressing (ELID) grinding is one of the most accurate grinding methods. The grinding wheel is dressed electrochemically and in-process to maintain the accuracy of the grinding. During the grinding operation one side of the wheel takes part in the grinding operation whereas the other side of the wheel is being dressed by electrochemical reaction.

25. GRINDING WHEEL… A grinding wheel is an expendable wheel used for various grinding and abrasive machining operations. It is generally made from a matrix of coarse abrasive particles pressed and bonded together to form a solid, circular shape, various profiles and cross sections are available depending on the intended usage for the wheel. To maintain uniformity throughout the country in the system of making grinding wheel, the Bureau of Indian Standard has devised a standard system to be followed by all manufacturer. To maintain uniformity throughout the country in the system of making grinding wheel, the Bureau of Indian Standard has devised a standard system to be followed by all manufacturer- 1. Abrasive 2. Grain size 3. Grade 4. Structure 5. Bond

26. DIFFERENT SHAPES OF GRINDINGWHEELS

27. Finishing Operation To ensure reliable performance and prolonged service life of modern machinery, its components require to be manufactured not only with high dimensional and geometrical accuracy but also with high surface finish. The surface finish has a vital role in influencing functional characteristics like wear resistance, fatigue strength, corrosion resistance and power loss due to friction. The finishing operations are assigned as the last operations in the single part production cycle usually after the conventional or abrasive machining operations, but also after net shape processes such as powder metallurgy, cold flash less forging, etc.

28. Finishing Operations Lapping Buffing Honing Super finishing Wire brushing Polishing Electro polishing Magnetic-field-assisted polishing

29. Lapping In lapping, instead of a bonded abrasive tool, oil-based fluid suspension of very small free abrasive grains (aluminum oxide and silicon carbide, with typical grit sizes between 300 and 600) called a lapping compound is applied between the work piece and the lapping tool. The lapping tool is called a lap, which is made of soft materials like copper, lead or wood. The lap has the reverse of the desired shape of the work part. To accomplish the process, the lap is pressed against the work and moved back and forth over the surface. Lapping is sometimes performed by hand, but lapping machines accomplish the process with greater consistency and efficiency.

30. Polishing Polishing is a finishing operation to improve the surface finish by means of a polishing wheel made of fabrics or leather and rotating at high speed. The abrasive grains are glued to the outside periphery of the polishing wheel. Polishing operations are often accomplished manually. Buffing Buffing is a finishing operation similar to polishing, in which abrasive grains are not glued to the wheel but are contained in a buffing compound that is pressed into the outside surface of the buffing wheel while it rotates. As in polishing, the abrasive particles must be periodically replenished. As in polishing, buffing is usually done manually, although machines have been designed to perform the process automatically. Buffing wheels are made of discs of linen, cotton, broad cloth and canvas

31. Honing Honing is a finishing process, in which a tool called hone carries out a combined rotary and reciprocating motion while the work piece does not perform any working motion. Most honing is done on internal cylindrical surface, such as automobile cylindrical walls. The honing stones are held against the work piece with controlled light pressure. The honing head is not guided externally but, instead, floats in the hole, being guided by the work surface It is desired that honing stones should not leave the work surface stroke length must cover the entire work length. Honing is a finishing process performed by a honing tool, which contains a set of three to a dozen and more bonded abrasive sticks. The sticks are equally spaced about the periphery of the honing tool. They are held against the work surface with controlled light pressure, usually exercised by small springs.

32. HONING

33. WELDING Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing fusion, which is distinct from lower temperature metal-joining techniques such as brazing and soldering, which do not melt the base metal. In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that is usually stronger than the base material. Pressure may also be used in conjunction with heat, or by itself, to produce a weld. Welding also requires a form of shield to protect the filler metals or melted metals from being contaminated or oxidized.

34. Some of the best known welding methods include: • Oxy-fuel welding – also known as oxyacetylene welding or oxy welding, uses fuel gases and oxygen to weld and cut metals. • Shielded metal arc welding (SMAW) – also known as "stick welding" or "electric welding", uses an electrode that has flux around it to protect the weld puddle. The electrode holder holds the electrode as it slowly melts away. Slag protects the weld puddle from atmospheric contamination. • Gas tungsten arc welding(GTAW) – also known as TIG (tungsten, inert gas), uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by an inert shielding gas such as argon or helium. • Gas metal arc welding (GMAW) – commonly termed MIG (metal, inert gas), uses a wire feeding gun that feeds wire at an adjustable speed and flows an argon-based shielding gas or a mix of argon and carbon dioxide (CO2) over the weld puddle to protect it from atmospheric contamination. • Flux-cored arc welding (FCAW) – almost identical to MIG welding except it uses a special tubular wire filled with flux; it can be used with or without shielding gas, depending on the filler.

35. Submerged arc welding (SAW) – uses an automatically fed consumable electrode and a blanket of granular fusible flux. The molten weld and the arc zone are protected from atmospheric contamination by being "submerged" under the flux blanket. • Electro slag welding (ESW) – a highly productive, single pass welding process for thicker materials between 1 inch (25 mm) and 12 inches (300 mm) in a vertical or close to vertical position. • Electric resistance welding (ERW) – a welding process that produces coalescence of laying surfaces where heat to form the weld is generated by the electrical resistance of the material. In general, an efficient method, but limited to relatively thin material.

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