4. 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.
9. 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
10. 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
11. 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
14. 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
17. 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
20. 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
21. 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
30. 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%
31. 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
34. 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
36. 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
37. 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.
38. 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.
39. 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
40. 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
42. 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.
43. 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
47. Bulk metal
forming
Sheet metal
forming
• Rolling
• Forging
• Extrusion
• Drawing
• Shearing
• Bending
• Deep drawing
Hydroforming
• Tube Hydroforming
• Sheet hydroforming
CLASSIFICATION OF METAL FORMING
PROCESSES
48. compression process to reduce the-Rolling
thickness of a slab by a pair of rolls.
BULK METAL FORMING PROCESSES
49. 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
51. Drawing - pulling a wire or bar through a die opening.
BULK METAL FORMING PROCESSES
52. 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
54. 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
56. 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.
57. 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.
58. 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.
59. 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.
60. 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.
61. 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.
