M ANUFACTURING Processes and Techniques O UTLINE THEORY OF METAL - - PowerPoint PPT Presentation

MANUFACTURING

Processes and Techniques

KINGDOM OF SAUDI ARABIA Prince Sattam bin Abdulaziz University Mechanical Engineering Department

ةيدوعسلا ةيبرعلا ةكلمملا

ريملؤا ةعماجماطس زيزعلا دبع نب ةسدنهلا مسق ةيكيناكيملا

OUTLINE

 THEORY OF METAL CUTTING  TRADITIONAL AND NON-TRADITIONAL MACHINING

PROCESSES.

 WELDING & CASTING.  TOLERANCE AND FITS  METAL FORMING

THEORY OF METAL CUTTING

MACHINING

Positive rake angles:

• Make the tool more sharp and pointed.
• Reduce cutting forces and power

requirements.

• Helps in the formation of continuous chips

in ductile materials.

• Help avoid the formation of a built-up edge.

Negative rake angles, by contrast:

• Increasing the strength of the cutting edge.
• Increase the cutting forces.
• Increase friction, resulting in higher

temperatures.

• Improve surface finish.

WHY MACHINING IS IMPORTANT

CUTTING TOOL

TYPES OF CHIPS

TYPES OF CHIPS

The time to machine from one end of a cylindrical workpart to the other is given by:

Where Tm = machining time, min; and L = length of the cylindrical workpart, mm (in)

more direct computation of the machining time is provided by the following equation:

Where Do = work diameter, mm (in); L = workpart length, mm (in); f = feed, mm/rev (in/rev); and v = cutting speed, mm/min (in/min).

METAL CUTTING CALCULATIONS

The rotational speed in turning is related to the desired cutting speed at the surface of the cylindrical workpiece by the equation

Where N = rotational speed, rev/min; v = cutting speed, m/min (ft/min); and Do = original diameter of the part, m (ft).

The material removal rate.

METAL CUTTING CALCULATIONS

The turning operation reduces the diameter of the work from its original diameter Do to a final diameter Df, as determined by the depth of cut d: The feed in turning is generally expressed in mm/rev (in/rev). This feed can be converted to a linear travel rate in mm/min (in/min) by the formula:

Where fr = feed rate, mm/min (in/min); and f = feed, mm/rev (in/rev).

METAL CUTTING CALCULATIONS

TRADITIONAL AND NON-TRADITIONAL

MACHINING PROCESSES

TRADITIONAL MACHINING PROCESSES MACHINING BY CUTTING

Turning Drilling Milling (face)

Milling (peripheral)

TRADITIONAL MACHINING PROCESSES MACHINING BY CUTTING

In shaping, the primary motion is performed by the tool, and feed by the workpiece. In Planing, the primary cutting motion is performed by the workpiece and feed motion is imparted to the cutting tool. Broaching: use of a multiple-tooth cutting tool moved linearly relative to the workpiece in the direction of the tool axis

TRADITIONAL MACHINING PROCESSES MACHINING BY ABRASION

Surface Grinding Cylindrical Grinding

TRADITIONAL MACHINING PROCESSES MACHINING BY ABRASION

Honing Lapping

NON-TRADITIONAL MACHINING PROCESSES MECHANICAL ENERGY PROCESSES

Ultrasonic machining Water Jet Cutting (WJC) Abrasive Jet Machining (AJM)

Speed 300 m/s 0.025 mm fine abrasive particles

0.05 to 0.125 mm

NONTRADITIONAL MACHINING PROCESSES ELECTROCHEMICAL MACHINING PROCESSES Electrochemical Machining (ECM) Electrochemical Grinding (ECG)

NON-TRADITIONAL MACHINING PROCESSES THERMAL ENERGY PROCESSES

(Wire EDM)

Plasma Arc Cutting (PAC)

EDM

Laser Beam Machining (LBM)

MULTIPLE CHOICE QUESTIONS (MCQ)

• Complete the Tool and WP motions for traditional machine tools.

Machining Process Tool and WP movements Turning WP Tool Drilling Tool Tool Milling Tool WP Shaping Tool WP Cylindrical grinding Tool WP

MULTIPLE CHOICE QUESTIONS

• The process utilizing mainly thermal energy for removing material is

(a) Ultrasonic Machining (b) Electrochemical Machining (c) Abrasive Jet Machining (d) Laser Beam Machining

• Match the following traditional and non-traditional machining

processes with the corresponding material removal mechanisms

Machining process Mechanism of material removal

• P. Grinding
• 1. Abrasion
• Q. Turning
• 2. Erosion
• R. Chemical machining
• 3. Chip removal
• S. Electro-discharge

machining

• 4. Corrosive reaction
• T. Ultrasonic machining
• 5. Fusion and vaporization

P-1 ; Q-3 ; R-4 ; S-5 ; T-2

WELDING & CASTING

TYPES OF WELDING

ARC WELDING

MIG welding Submerged arc welding TIG Welding SMAW(MMA) welding

Coating is a combination of chemicals in SMAW(MMA) welding: Cellulosic electrodes contain cellulose Rutile electrodes titanium

• xide (rutile)

Basic electrodes contain calcium carbonate (limestone) and calcium fluoride (fluorspar)

SMAW(MMA) & TIG WELDING

OXYACETYLENE WELDING

Reducing or Carburizing: Excess acetylene (0.9:1) (Alloy steels and aluminium alloys) Oxidizing : Excess oxygen (1.5:1) (Brass, Bronzes, copper) Neutral : Equal acetylene & oxygen (low carbon steel, mild steels).

RESISTANCE WELDING

WELDING

 Types of welded joints:

SOLDERING AND BRAZING

SOLDERING & M.C.Q BRAZING

The commonly used flux in brazing is



Borax



Rosin



Lead sulphide



Zinc chloride Which of the following is function(s) of flux used in brazing? i- Protect surface from oxidation ii- Reduce surface tension of filler iii- Assist its penetration



i only



ii only



i and ii



i, ii and iii In soldering the melting point of filler metal is



a - below 420 ◦ C



b- below 450 ◦ C



c - below 460 ◦ C



d - below 540 ◦ C



The composition of soft solder is



a- lead 37% tin 63%



b- lead 50% tin 50%



c- lead 63% tin 37%



d- lead 70% tin 30%

SAMPLES OF M.C.Q WELDING

Which of the following welding process uses non-consumable electrodes?



TIG welding



MIG welding



Manual arc welding



Submerged arc welding The temperature of oxy-hydrogen flame is __________ oxy-acetylene flame.



same as



less than



more than In submerged arc welding, an arc is produced between a



carbon electrode and the work



metal electrode and the work



bare metal electrode and the work



two tungsten electrodes and the work In shielded arc welding



large electrode is used



welding rod coated with slag is used



welding rod coated with fluxing material is used



none of the above In electric resistance welding, voltage required for heating is



1 to 5 volts



6 to 10 volts



11 to 20 volts



50 to 100 volts

The oxy-acetylene gas used in gas welding produce a flame temperature of



1800°C



2100°C



2400°C



3200°C

CASTING

PATTERN

PATTERN

MOLDING MATERIALS

Major part of Molding material in sand casting are:

• 1. 70-85% silica sand (SiO2)
• 2. 10-12% bonding material e.g., clay cereal etc.
• 3. 3-6% water

Classification of sand casting defects

CASTING WITH EXPENDABLE MOULD: INVESTMENT CASTING

PERMANENT MOULD CASTING: DIE CASTING

In Die casting the molten metal is forced to flow into a permanent metallic mold under moderate to high pressures, and held under pressure during solidification

DIE CASTING

This uses pressures up to 35 MPa and is used for zinc, tin, lead, and their alloys In this process, pressures as high as 150 MPa are used. The storing chamber is not heated. This process is used mainly for metals and alloys having relatively higher melting point e.g., aluminium, magnesium and their alloys.

CENTRIFUGAL CASTING

• A permanent mold made of metal or ceramic is rotated at high

speed (300 to 3000 rpm). The molten metal is then poured into the mold cavity and due to centrifugal action the molten metal conform to the cavity provided in the mould.

• Castings are known for their higher densities in the outer most

regions.

• The process gives good surface finish
• Applications: pipes, bushings, gears, flywheels etc.

SAMPLES OF M.C.Q CASTING

 Sand casting is which of the following types?

(a) expendable mold, or (b) permanent mold.

 The upper half of a sand casting mold is called

which of the following? (a) cope, or (b) drag.

 In casting, a flask is which one of the following?

(a) beverage bottle for foundry men, (b) box which holds the cope and drag, (c) container for holding liquid metal, (d) metal which extrudes

SAMPLES OF M.C.Q CASTING

In foundry work, a runner is which one of the following? (a) channel in the mold leading from the Down sprue to the main mold cavity, (b) foundry man who moves the molten metal to the mold, or (c) vertical channel into which molten metal is poured into the mold. Total solidification time is defined as which one of the following? (a) time between pouring and complete solidification, (b) time between pouring and cooling to room temperature, (c) time between solidification and cooling to room temperature, or (d) time to give up the heat of fusion. In a cold chamber die casting machine

 melting pot is separate from the machine  melting pot is an integral part of the machine  melting pot may have any location  low temperature and pressure is used

TOLERANCE AND FITS

TOLERANCE AND FITS

Three ways to specify tolerance limits for a nominal dimension of 2.500: (a) bilateral, (b) unilateral, and (c) limit dimensions.

Tolerance is the total amount by which a specific dimension is permitted to vary. The tolerance is the difference between the maximum and minimum limits.

Fit is degree of tightness between two parts. Fit types:

 Clearance Fit – tolerance of mating parts always leaves

a space

 Interference Fit – tolerance of mating parts always

results in interference

 Transition Fit – sometimes interferes, sometimes clears

TOLERANCE AND FITS

Fits in Basic Shaft System

TOLERANCE AND FITS

Fits in Basic Hole System

TOLERANCE AND FITS

METAL FORMING

Bulk metal forming Sheet metal forming

• Rolling
• Forging
• Extrusion
• Drawing
• Shearing
• Bending
• Deep drawing

Hydroforming

• Tube Hydroforming
• Sheet hydroforming

CLASSIFICATION OF METAL FORMING

PROCESSES

compression process to reduce the

• Rolling

thickness of a slab by a pair of rolls.

BULK METAL FORMING PROCESSES

Shaping material by hammering or – Forging pressing

• Impression die forging ( closed die forging)

presses metal between two dies (called tooling) that contain a precut profile of the desired part.

• Open die forging is performed between flat dies

with no precut profiles is the dies.

• Hot versus cold forging

Forging process sequence

BULK METAL FORMING PROCESSES

compression process squeezing metal

• Extrusion

flow a die opening.

BULK METAL FORMING PROCESSES

Drawing - pulling a wire or bar through a die opening.

BULK METAL FORMING PROCESSES

SHEET METAL FORMING PROCESSES

Forming on metal sheets, strips, and coils. The process is normally a cold working process using a set of punch and die. Bending - straining of a metal sheet to form an angle bend. Drawing - forming a sheet into a hollow or concave shape. Shearing - not a forming process but a cutting process

SHEET METAL FORMING PROCESSES

TUBE HYDROFORMING PROCESS

C Tools / Dies A Incoming Tube D Tool-Workpiece Interface E Deformation Mechanics F Equipment / Environment / Press G Hydroformed part B Bending / Preforming

FAILURE MODE IN THF PROCESS

MCQ IN METAL FORMING

Q1: The process of forming metal parts using a fluid pressure medium and die constraint is called:



A) Forging process.



B) Rolling process.



C) Tube Hydroforming process. Q2: Pressing metal between two dies that contain a precut profile of the desired part called:



A) Open die forging process.



B) Closed-die forging process.



C) Rolling process. Q3: The process of pulling a wire or bar through a die opening is called:



A) Open die forging process.



B) Drawing process.



C) Rolling process. Q4: In the rolling process, the rolls are rotating in:



A) Different direction.



B) Same direction.



C) Not rotating . Q5: Extrusion process can be classified as:



A) Sheet forming process.



B) Bulk forming process.



C) Hydroforming process.

MCQ IN METAL FORMING

Q1: The process of forming meal parts using a fluid pressure medium and die constraint is called:



A) Forging process.



B) Rolling process.



C) Tube Hydroforming process. Q2: Pressing metal between two dies that contain a precut profile of the desired part called:



A) Open die forging process.



B) Closed-die forging process.



C) Rolling process. Q3: The process of pulling a wire or bar through a die opening is called:



A) Open die forging process.



B) Drawing process.



C) Rolling process. Q4: In the rolling process, the rolls are rotating in:



A) Different direction.



B) Same direction.



C) Not rotating . Q5: Extrusion process can be classified as:



A) Sheet forming process.



B) Bulk forming process.



C) Hydroforming process.

MCQ IN METAL FORMING

Q1: The process of forming meal parts using a fluid pressure medium and die constraint is called:



A) Forging process.



B) Rolling process.



C) Tube Hydroforming process. Q2: Pressing metal between two dies that contain a precut profile of the desired part called:



A) Open die forging process.



B) Closed-die forging process.



C) Rolling process. Q3: The process of pulling a wire or bar through a die opening is called:



A) Open die forging process.



B) Drawing process.



C) Rolling process. Q4: In the rolling process, the rolls are rotating in:



A) Different direction.



B) Same direction.



C) Not rotating . Q5: Extrusion process can be classified as:



A) Sheet forming process.



B) Bulk forming process.



C) Hydroforming process.

MCQ IN METAL FORMING

Q1: The process of forming meal parts using a fluid pressure medium and die constraint is called:



A) Forging process.



B) Rolling process.



C) Tube Hydroforming process. Q2: Pressing metal between two dies that contain a precut profile of the desired part called:



A) Open die forging process.



B) Closed-die forging process.



C) Rolling process. Q3: The process of pulling a wire or bar through a die opening is called:



A) Open die forging process.



B) Drawing process.



C) Rolling process. Q4: In the rolling process, the rolls are rotating in:



A) Different direction.



B) Same direction.



C) Not rotating . Q5: Extrusion process can be classified as:



A) Sheet forming process.



B) Bulk forming process.



C) Hydroforming process.

MCQ IN METAL FORMING

Q1: The process of forming meal parts using a fluid pressure medium and die constraint is called:



A) Forging process.



B) Rolling process.



C) Tube Hydroforming process. Q2: Pressing metal between two dies that contain a precut profile of the desired part called:



A) Open die forging process.



B) Closed-die forging process.



C) Rolling process. Q3: The process of pulling a wire or bar through a die opening is called:



A) Open die forging process.



B) Drawing process.



C) Rolling process. Q4: In the rolling process, the rolls are rotating in:



A) Different direction.



B) Same direction.



C) Not rotating . Q5: Extrusion process can be classified as:



A) Sheet forming process.



B) Bulk forming process.



C) Hydroforming process.

MCQ IN METAL FORMING

Q1: The process of forming meal parts using a fluid pressure medium and die constraint is called:



A) Forging process.



B) Rolling process.



C) Tube Hydroforming process. Q2: Pressing metal between two dies that contain a precut profile of the desired part called:



A) Open die forging process.



B) Closed-die forging process.



C) Rolling process. Q3: The process of pulling a wire or bar through a die opening is called:



A) Open die forging process.



B) Drawing process.



C) Rolling process. Q4: In the rolling process, the rolls are rotating in:



A) Different direction.



B) Same direction.



C) Not rotating . Q5: Extrusion process can be classified as:



A) Sheet forming process.



B) Bulk forming process.



C) Hydroforming process.

THANKS AND GOOD LUCK 