Drilling process Sheet metal process Turning process Welding

Drilling process Sheet metal process Turning process Welding process CAM 1/2/2022 ME 1001 Unit-3 Lecture -1 1

SHEET METAL PROCESS 1/2/2022 ME 1001 Unit-3 Lecture -1 2

Sheet metal process Rolled metals of gauge 10 to 20 are considered as sheet metals The metals include steel, copper, brass, aluminium, zinc etc. 1/2/2022 ME 1001 Unit-3 Lecture -1 3

Sheet metal operations Major classifications include 1. Shearing ◦ Blanking ◦ Piercing ◦ Punching ◦ Notching 2. Bending 3. Drawing 1/2/2022 ME 1001 Unit-3 Lecture -1 4

Shearing 1/2/2022 ME 1001 Unit-3 Lecture -1 5

Shearing Two or more blades are used for cutting the sheet at multiple or single point Pressure is generally applied on the top blade causing the shear force which tears the sheet. The amount of force is applied on the system using a hydraulic press or mechanical press 1/2/2022 ME 1001 Unit-3 Lecture -1 6

Blanking 1/2/2022 ME 1001 Unit-3 Lecture -1 7

Blanking Instead of blades a blanking press shape is used in this process. Once the sheet metal is inserted in between the blanking die and the punch high pressure is applied on the punch The output component is ejected from the die and the scrap is taken out 1/2/2022 ME 1001 Unit-3 Lecture -1 8

Piercing and punching 1/2/2022 ME 1001 Unit-3 Lecture -1 9

Piercing and punching Similar to the blanking operation but at multiple points. The scrap is the blanked components and the remaining sheet is the finished product. 1/2/2022 ME 1001 Unit-3 Lecture -1 10

Notching 1/2/2022 ME 1001 Unit-3 Lecture -1 11

Notching This is a process of removing metal into to the desired shape from the side or edge of the sheet 1/2/2022 ME 1001 Unit-3 Lecture -1 12

Bending Types of bending Edge bending V- bending U- bending 1/2/2022 ME 1001 Unit-3 Lecture -1 13

Edge bending 1/2/2022 ME 1001 Unit-3 Lecture -1 14

V- bending 1/2/2022 ME 1001 Unit-3 Lecture -1 15

U bending and channel bending 1/2/2022 ME 1001 Unit-3 Lecture -1 16

Spring back effect in sheet metals 1/2/2022 ME 1001 Unit-3 Lecture -1 17

Drawing – sheet metal 1/2/2022 ME 1001 Unit-3 Lecture -1 18

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Sheet metal presses Classified into Manually operated press ◦ Fly press ◦ Power presses ◦ Mechanical press ◦ Hydraulic press ◦ Pneumatic press 1/2/2022 ME 1001 Unit-3 Lecture -1 20

Manual press 1/2/2022 ME 1001 Unit-3 Lecture -1 21

Mechanical press 1/2/2022 ME 1001 Unit-3 Lecture -1 22

Pneumatic press 1/2/2022 ME 1001 Unit-3 Lecture -1 23

Hydraulic press 1/2/2022 ME 1001 Unit-3 Lecture -1 24

WELDING 1/2/2022 ME 1001 Unit-3 Lecture -1 25

Joining methods Welding ◦ Fusion ◦ Brazing ◦ Soldering 1/2/2022 ME 1001 Unit-3 Lecture -1 26

Definition Process of joining similar metals by application of heat With or without application of pressure With or without application of filler material Permanent joints can be produced using welding 1/2/2022 ME 1001 Unit-3 Lecture -1 27

Classifications Gas welding Oxy acetylene welding Oxy hydrogen welding Arc welding Metal electrode welding Carbon electrode welding Resistance welding Spot welding Seam welding Projection welding Butt welding 1/2/2022 ME 1001 Unit-3 Lecture -1 28

Terminology Base metal: work piece or part to be joined. Weld bead: material deposited by welding process Puddle : portion of base metal at the joint Weld pass: movement of welding torch or arc from one end to other Tack weld: temporary welding done at the ends 1/2/2022 ME 1001 Unit-3 Lecture -1 29

Weld bead 1/2/2022 ME 1001 Unit-3 Lecture -1 30

Puddle portion 1/2/2022 ME 1001 Unit-3 Lecture -1 31

Tack weld Tack 1/2/2022 ME 1001 Unit-3 Lecture -1 32

Gas welding It is a fusion welding process Heat melts the parent metal and fuses with the filler metal which are in molten stage Suitable for the sheets having thickness 2 to 50 mm and materials having thickness 15 mm Filler materials generally in the form of rods which can melt and form as filler and creates a flux bond 1/2/2022 ME 1001 Unit-3 Lecture -1 33

Process 1/2/2022 ME 1001 Unit-3 Lecture -1 34

Equipment 1/2/2022 ME 1001 Unit-3 Lecture -1 35

Combustion cycle of oxyacetylene flame 2 C 2 H 2 + 5 O 2 = 4 CO 2 + 2 H 2 O + heat (300 Kcal/mole) Temperature ranges to 3300 deg c 1/2/2022 ME 1001 Unit-3 Lecture -1 36

Flame types 1/2/2022 ME 1001 Unit-3 Lecture -1 37

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Arc welding Also known as metal electrode welding Classified into two Metal arc welding Carbon arc welding 1/2/2022 ME 1001 Unit-3 Lecture -1 39

Working The work piece is clamped with a cable which is the cathode (-) terminal. The arc is connected to the anode (+) terminal of the Dc supply. When these two are brought together at a distance of the 2 -4 mm the current continues to flow causing the plasma , and an electric arc is formed which fuses the two base metals 1/2/2022 ME 1001 Unit-3 Lecture -1 40

Working Approximately 1 Kwh of electricity will a heat of around 1000 j of heat. The temperature of the arc is around 6000 to 7000 deg c 1/2/2022 ME 1001 Unit-3 Lecture -1 41

Metal arc welding process 1/2/2022 ME 1001 Unit-3 Lecture -1 42

Arc welding equipment Comprises of the following components Power source (AC or DC) Electrode holder Ground clamp Cabels 1/2/2022 ME 1001 Unit-3 Lecture -1 43

Diagrammatic view 1/2/2022 ME 1001 Unit-3 Lecture -1 44

Pictorial view 1/2/2022 ME 1001 Unit-3 Lecture -1 45

Arc welding power sources Transformer (AC) Rectifier (AC to DC) Generator (AC or DC) 1/2/2022 ME 1001 Unit-3 Lecture -1 46

Polarities Work piece can be interchanged between cathode and anode and similarly the electrode If the electrode is anode and work piece is clamped to cathode it is called ‘Straight polarity’ If the electrode is cathode and the work piece is anode it is reverse polarity 1/2/2022 ME 1001 Unit-3 Lecture -1 47

Electrodes Bifurcated into two variants Consumable or cruisible electrode Non consumable 1/2/2022 ME 1001 Unit-3 Lecture -1 48

Consumable electrode 1/2/2022 ME 1001 Unit-3 Lecture -1 49

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Properties of flux coating Gas shielding Slag Arc stabilizing De oxidizing the weld 1/2/2022 ME 1001 Unit-3 Lecture -1 51

Cleaning tools Chipping hammer Metal wire brush 1/2/2022 ME 1001 Unit-3 Lecture -1 52

Welding techniques Forehand welding Backhand welding 1/2/2022 ME 1001 Unit-3 Lecture -1 53

Forehand welding 1/2/2022 ME 1001 Unit-3 Lecture -1 54

Backhand welding 1/2/2022 ME 1001 Unit-3 Lecture -1 55

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Types of welding joints 1/2/2022 ME 1001 Unit-3 Lecture -1 57

Resistance welding 1/2/2022 ME 1001 Unit-3 Lecture -1 58

Soldering and brazing Both are liquid based bonding processes Soldering Method of joining two are more pieces of metal by a means of fusible alloy, which is called as the solder Flux is added to prevent the oxidation of metals during the process 1/2/2022 ME 1001 Unit-3 Lecture -1 59

Steps in soldering process Shaping the parts to be joined Removal of dirt and grease Flux application on the surfaces Application of molten solder for wetting 1/2/2022 ME 1001 Unit-3 Lecture -1 60

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Brazing Process of joining two dissimilar metals in which metals are heated to a suitable temperature and filler material in the molten form is applied In this flux may or may not be used 1/2/2022 ME 1001 Unit-3 Lecture -1 62

DRILLING 1/2/2022 ME 1001 Unit-3 Lecture -1 63

Drilling Process of making a circler cut in the work piece. The tool in the drilling process is much harder than the work piece 1/2/2022 ME 1001 Unit-3 Lecture -1 64

Classification Bench drilling machine Sensitive drilling machine Radial drilling machine Gang drilling machine Multi spindle type Deep hole drilling machine Transfer drilling 1/2/2022 ME 1001 Unit-3 Lecture -1 65

Sensitive drilling machine 1/2/2022 ME 1001 Unit-3 Lecture -1 66

components Spindle Sleeve Column Head Work table Base Drill feed 1/2/2022 ME 1001 Unit-3 Lecture -1 67

Radial drilling machines 1/2/2022 ME 1001 Unit-3 Lecture -1 68

Operations using drilling machine Counter boring Drilling Tapping Boring Reaming Counter sinking 1/2/2022 ME 1001 Unit-3 Lecture -1 69

Counter boring: A counter bore (symbol: � ) is a cylindrical flatbottomed hole that enlarges another coaxial hole, or the tool used to create that feature. 1/2/2022 ME 1001 Unit-3 Lecture -1 70

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Tapping 1/2/2022 ME 1001 Unit-3 Lecture -1 72

Boring 1/2/2022 ME 1001 Unit-3 Lecture -1 73

Reaming : Process of sizing and finishing the already drilled hole. 1/2/2022 ME 1001 Unit-3 Lecture -1 74

Counter sinking A countersink (symbol: � ) is a conical hole cut into a manufactured object, or the cutter used to cut such a hole. A common use is to allow the head of a countersunk bolt or screw, when placed in the hole, to sit flush with or below the surface of the surrounding material (by comparison, a counter bore makes a flatbottomed hole that might be used with a socket-head cap screw). 1/2/2022 ME 1001 Unit-3 Lecture -1 75

Counter sinking 1/2/2022 ME 1001 Unit-3 Lecture -1 76

Nomenclature of twist drill 1/2/2022 ME 1001 Unit-3 Lecture -1 77

Drill holding device 1/2/2022 ME 1001 Unit-3 Lecture -1 78

Drill supporting devices Helps in holding the work piece which is under operating at the arrest position. Classified into two ◦ Vice mounting ◦ Table or Base mounting 1/2/2022 ME 1001 Unit-3 Lecture -1 79

Vice mounting 1/2/2022 ME 1001 Unit-3 Lecture -1 80

Table mounting 1/2/2022 ME 1001 Unit-3 Lecture -1 81

Operating conditions in drilling Cutting Speed (v): - It’s the peripheral speed of the drill v = *D*N where D = dia of the drill in m N = Speed of rotation in rpm Feed Rate (f): It’s the movement of drill along the axis (mm/rev) Depth of Cut (d): The distance from the machined surface to the drill axis 1/2/2022 ME 1001 Unit-3 Lecture -1 82 d=D/2

Material Removal Rate: It’s the volume of material removed by the drill per unit time MRR = ( D 2 / 4) * f * N mm 3 / min Machining Time (T) : It depends upon the length (l) of the hole to be drilled , to the Speed (N) and feed (f) of the drill t = L / (f N) min Time required to drill : D t/ 1000*feed*cutting speed 1/2/2022 ME 1001 Unit-3 Lecture -1 83

Numerical Three holes of diameter 15 mm are to be drilled on a 15 mm thick plate if the cutting speed is 30 meters per minute. Calculate the time required to complete 12 such plates assuming the feed =0. 12 mm/rev 1/2/2022 ME 1001 Unit-3 Lecture -1 84

TURNING PROCESS LATHE MACHINE 1/2/2022 ME 1001 Unit-3 Lecture -1 85

Turning process The process of material removal for making the desired shape out of a work piece is called turning. In this process the work piece will be held in a holding device and rotated against a work piece at stationary. 1/2/2022 ME 1001 Unit-3 Lecture -1 86

Lathe machine It’s a machine tool used for shaping the work piece firmly and rotate or turned, while the cutting tool advances into the work causing the material removal or cutting action. 1/2/2022 ME 1001 Unit-3 Lecture -1 87

Photographic view 1/2/2022 ME 1001 Unit-3 Lecture -1 88

Line diagram of lathe 1/2/2022 ME 1001 Unit-3 Lecture -1 89

Components of lathe machine Bed Head stock Saddle Tail stock Carriage Spindle Gear box Tool post Lead screws Leg Chuck 1/2/2022 ME 1001 Unit-3 Lecture -1 90

Specifications of lathe machine Swing – max dia that can be machined Distance b/w head and tail stock Length of bed Horse power of the motor Cutting speed range Screw cutting range Feed range Accuracy achievable 1/2/2022 ME 1001 Unit-3 Lecture -1 91

Classification Speed lathes Engine lathes Bench lathes Tool room lathes Turret lathes Center lathes Capstan lathes 1/2/2022 ME 1001 Unit-3 Lecture -1 92

Head stock 1/2/2022 ME 1001 Unit-3 Lecture -1 93

Bed 1/2/2022 ME 1001 Unit-3 Lecture -1 94

Saddle 1/2/2022 ME 1001 Unit-3 Lecture -1 95

Tail stock 1/2/2022 ME 1001 Unit-3 Lecture -1 96

Tool post 1/2/2022 ME 1001 Unit-3 Lecture -1 97

Chuck 1/2/2022 ME 1001 Unit-3 Lecture -1 98

Types of chucks Universal scroll chuck Independent jaw chuck Drill chuck Magnetic chuck Collet chuck 1/2/2022 ME 1001 Unit-3 Lecture -1 99

Lathe centers Supporting devices for the work piece Most of them will have a tapered point with 60 deg These are classified into Live center – which rotates along with work piece Dead center – which does not 1/2/2022 ME 1001 Unit-3 Lecture -1 100

classification of centers Male center Half male center Female center V center Ball bearing center or Male live center Self driving center Pipe center 1/2/2022 ME 1001 Unit-3 Lecture -1 101

Tool Some important characteristics of tool are. 1. high hardness 2. Hot hardness 3. Wear resistance 4. Toughness 5. Low friction 6. Thermal characteristics 1/2/2022 ME 1001 Unit-3 Lecture -1 102

Single point cutting tool Tool which has only one cutting point action proceeding at one time. 1/2/2022 ME 1001 Unit-3 Lecture -1 103

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Tool types based on operations Turning operation Threading tool Parting tool or cut off tool Grooving tool Form tool Chamfering tool Knurling tool 1/2/2022 ME 1001 Unit-3 Lecture -1 105

Operation conditions Cutting speed S= peripheral speed ◦ =πDN/1000 m/min ◦ D= dia of the work piece ◦ N= revolutions of the chuck ◦ Since the material passes the stationary cutting tool with its peripheral speed ◦ So V = S ◦ V= πDN/1000 1/2/2022 ME 1001 Unit-3 Lecture -1 106

Operation conditions Feed: Termed as the applied distance and the tool bit advances along the work distance. Depth of cut: Termed as the perpendicular distance that the tool moves into the work piece Given by D= (D 1 -D 2)/2 mm D 1 is the initial dia of the work piece D 2 is the final dia of the work piec 1/2/2022 ME 1001 Unit-3 Lecture -1 107

Operation conditions Metal removal rate: MRR is the volume of the material removed in a unit time interval MRR= πDd. FNcubic mm/min Interms of the cutting spee MRR= 1000 vd. F D= initial dia of the work piece d = final dia of the work piece F= feed N=RPM 1/2/2022 ME 1001 Unit-3 Lecture -1 108

Taper turning Let D 1 is the major dia And D 2 is the minor dia L be the total length of the taper alpha α be the angle of the taper Then tan α = (D 1 -D 2)/2 L 1/2/2022 ME 1001 Unit-3 Lecture -1 109

Different operations on lathe 1/2/2022 ME 1001 Unit-3 Lecture -1 110