WorksheetsAMT UNIT
Total questions: 100
Worksheet time: 55mins
Why is ribbing used in plastic components?
To improve strength without increasing thickness
To reduce transparency
To make it flexible
To improve surface finish
Why are thermosets not recyclable?
They are soluble in solvents
They harden permanently after curing
They are highly crystalline
They melt at low temperature
In calendaring, the product usually obtained is:
Pipes
Moulded gears
Hollow containers
Sheets and films
Why are twin screw extruders preferred over single screw extruders in compounding?
They consume less power
They provide better mixing and dispersion
They run at higher speed
They are cheaper
Liquid Crystal Polymers (LCPs) are used in:
Disposable bottles
Plastic bags
Food packaging
High-temperature electrical connectors
The reciprocating screw injection moulding machine is preferred over plunger type because:
It requires less maintenance
It has higher clamping force
It gives better mixing and melting of material
It consumes less electricity
Which of the following is a thermosetting plastic?
Polypropylene
Polyethylene
Bakelite
Nylon
Which of the following is a general guideline in plastic product design?
Keep uniform wall thickness
Use sharp corners
Always use very thick walls
Avoid draft angles
Why is venting provided in injection moulds?
To remove trapped gases and prevent defects
To reduce mould temperature
To increase product strength
To reduce raw material usage
Which plastic becomes soft on heating and hard on cooling repeatedly?
Thermoplastic
Thermoset
Elastomer
Composite
Why are fillets provided instead of sharp corners in plastic parts?
To reduce cooling times only
To increase brittleness
To improve electrical conductivity
To improve material flow and reduce stress concentration
The advantage of gas-assisted injection moulding is:
Increases optical clarity
Reduces cost of dyes
Increases optical clarity
Reduces cycle times and warpage
Draft angles in mould design are provided to:
Improve strength of plastics
Improve transparency
Reduce shrinkage
Facilitate easy removal of part from the mould
Which one of the following should be avoided in plastic product design?
Uniform wall thickness
Draft angles
Sharp corners
Ribs for strength
Structural foams are mainly used because:
They reduce material weight while retaining strength
They are biodegradable
They have high optical clarity
They are highly elastic
Why is uniform wall thickness preferred in plastic components?
To reduce warpage and sink marks
To increase transparency
To reduce cost of raw material
To make it biodegradable
In extrusion, the screw is mainly used for:
Cooling
Feeding, melting and pumping
Coloring
Curing
Which type of shrinkage is more dominant in plastics?
Thermal shrinkage
Chemical shrinkage
Mould shrinkage
Elastic shrinkage
Which of the following is an engineering plastic?
(a)
Rotational moulding is most suitable for making:
Thin films
Large hollow items like tanks
Small gears
Profiles
Cladding is best described as:
Chemical diffusion of atoms into surface
Bonding of dissimilar metals for corrosion resistance and strength
Spraying of molten powder
Electrochemical deposition
Honing uses which type of tool?
Abrasive sticks mounted on mandrel
Polishing cloth
Grinding wheel
Single point tool
Why is hot machining used for hard-to-machine alloys?
It reduces cutting forces and tool wear
It increases tool hardness
It makes the workplace softer permanently
It increases thermal conductivity of the tool
Why is electroplating widely used for decorative coatings?
Provides bright finish and corrosion resistance
Increases hardness only
Reduces thermal expansion
Makes component non-magnetic
Burnishing improves surface finish by:
Material removal
Chemical reaction
Melting and solidification
Plastic deformation
Galvanizing deposits a layer of:
Copper
Zinc
Nickel
Tin
Which machining process is used for achieving tolerances in micron or sub-micron range?
Conventional turning
Ultra-precision machining
Broaching
Shaping
Why is honing often used in engine cylinders?
To reduce thermal expansion
To produce cross-hatch pattern for oil retention
To improve electrical properties
To reduce hardness
Micro and nano machining processes are widely used in:
Shipbuilding
Aerospace component repair
MEMS and semiconductor industries
Agricultural tools
Main advantage of burnishing over grinding is:
High material removal rate
Ability to cut hard metals
Lower thermal conductivity required
No material removal, only surface hardening and smoothening
Physical vapour deposition (PVD) includes:
Carburizing
Nitriding
Sputtering and evaporation
Hot dipping
Buffing is done using:
Soft wheel with fine abrasive paste
Abrasive particles bonded in wheel
Jet of water
Steel shot
Shot peening is mainly done to:
Improve ductility
Induce compressive stresses for fatigue strength improvement
Reduce corrosion resistance
Remove material
High-speed machining mainly uses:
High cutting speed and low feed
Low cutting speed and high feed
High depth of cut
Slow cutting with lubrication
Lapping is carried out using:
A cutting tool
Abrasive slurry and lap plate
Electrodes discharge
Buffing wheel
Powder coating is a process in which:
Fine dry powders are electrostatically sprayed and baked
Powder is mixed into molten metal
Metal surface is polished by powder abrasives
Powder is chemically bonded with solvent
In hot machining, the cutting tool is:
Heated before machining
Cooled using liquid nitrogen
Applied to a preheated workpiece
Rotated at high frequency
Which of the following is a hot-dip process?
(a)
Vapour deposition process in which chemical reaction occurs is:
CVD
PVD
Electroplating
Cladding
What is the difference between polishing and buffing?
Polishing is rougher, buffing is finer finishing
Buffing removes material, polishing does not
Polishing is chemical, buffing is mechanical
Both are identical processes
Which process uses high-intensity photons for machining?
PBM
PAM
LBM
EDM
Laser Beam Machining removes material mainly by:
Melting and vaporization
Plastic deformation
Chemical reaction
Chipping
The electrolyte commonly used in ECM is:
Kerosene
Sodium chloride solution
Compressed air
Ferric chloride
The carrier gas in AJM is usually:
Oxygen
Nitrogen
Air or CO2
Hydrogen
AJM is best suited for:
Ductile materials
Brittle materials like glass and ceramics
Soft plastics
All materials equally
The most common laser used in machining is:
Ruby laser
CO2 laser
Diode laser
Nd:YAG laser
An advantage of WJM is:
Heat-affected zone is formed
No tool wear and no thermal damage
Electrical conductivity required
Limited to conductive materials only
Abrasive Jet Machining uses:
Water jet only
High velocity gas with abrasive particles
Plasma arc
Ultrasonic vibrations
The material removal mechanism in USM is:
Erosion due to abrasive particle impact
Melting
Electrolysis
Chemical reaction
Plasma Arc Machining (PAM) temperature range is approximately:
200°C
2000°C
20000°C
20,000°C
In USM, the tool vibrates at a frequency of about:
50 Hz
20 kHz
2000 Hz
100 MHz
Plasma is defined as:
Ionized gas with free electrons and ions
Superheated gas
Liquid metal
Solidified gas
In EDM, the dielectric fluid is usually:
Air
Water
Kerosene or deionized water
Nitrogen
Which process uses a high voltage spark discharge for material removal?
EDM
ECM
CHM
PAM
In Chemical Machining, material is removed by:
Abrasive impact
Spark erosion
Selective chemical dissolution
High-speed jet
In AJM, material removal rate (MRR) depends on:
Gas pressure, abrasive size, and stand-off distance
Tool hardness
Workpiece conductivity
Electrolyte concentration
In Electrochemical Machining, material is removed by:
The nozzle material in WJM is generally:
Mild steel
Brass
Aluminum
Tungsten carbide
Electron Beam Machining requires:
High-pressure gas chamber
Vacuum chamber
Electrolytic bath
Magnetic field only
A major limitation of Electrochemical Machining is:
Burr formation
Tool wear is very high
Only non-conductive materials can be machined
High initial investment and electrolysis disposal problem
In CNC machines, servo motors are mainly used for:
Power supply regulation
Coolant circulation
Tool wear monitoring
Position and velocity control of machine axes
Tool offset in CNC programming is used to:
Adjust tool wear and diameter/radius compensation
Modify the programmed feed rate for machining operations
Regulate the programmed spindle speed during cutting process
Initiate the programmed machining cycle automatically
The CNC coordinate system that specifies points using radius and angle is:
Cartesian
Incremental
Polar
Absolute
M-codes in CNC programming are used for:
Miscellaneous functions like spindle/coolant control
Linear interpolation
Tool radius compensation
Workpiece coordinate system
G-codes in CNC are mainly used for:
Emergency stop
Switching coolant ON/OFF
Tool changing
Preparatory functions like movement and cycles
The tool changing operation in a CNC machining centre is carried out by:
Automatic Tool Changer (ATC)
Manual tool post
Turret only
Gearbox mechanism
Which positioning system in CNC programming defines a new position with respect to the previous position?
Absolute system
Polar system
Incremental system
Constant system
In CNC turning, the linear interpolation command "G01" is used to
Move tool at rapid speed
Generate straight-line profiles at feed rate
Generate circular arc
Perform thread cutting cycle
Which type of feedback system is generally used in CNC machines?
Open-loop system without feedback
Closed-loop system with position feedback
Manual loop with operator input
Hybrid loop without servo motors
The command "G00" is used for
Circular interpolation
Linear interpolation (feed)
Rapid traverse positioning
Canned drilling cycle
Circular interpolation in CNC programming is given by
G00
G01
G02 / G03
M06
CNC stands for
Central Numerical Control
Computer Numerical Control
Controlled Number Coding
Continuous Numerical Control
The CNC coordinate system based on a fixed origin is
Relative
Absolute
Incremental
Polar
The tool magazine in a CNC machining center is used for
Supporting spindle's vibration control
Monitoring and measuring tool wear
Holding and clamping workpieces
Storing multiple tools for automatic tool change
In a Coordinate Measuring Machine (CMM), the probe is used for
Detecting and recording object's surface coordinates
Holding and rotating the cutting tool
Storing multiple tools in the magazine
Supporting the workpiece during machining
The most accurate machine for measuring 3D part geometry in CNC inspection is
Which offset is used to set the workpiece origin relative to machine zero?
Tool offset
Program zero
Cutter compensation
Work offset
In a CNC turning centre, the spindle axis is considered as
X-axis
Y-axis
W-axis
Z-axis
Which component of a CNC turning center holds and rotates the workpiece
Tool turret
Chuck
Tailstock
Bed
The main advantages of CNC over NC machines is
Reduced initial investment and setup cost for the machine
Elimination of highly skilled operators for machine operation
Automatic error correction and flexibility in programming
Lower overall energy usage and reduced power consumption
STL files contains
Mass properties of the model
2D drawing annotations
Material property data
Geometrical data
Which material is commonly used in FDM?
Photopolymer resin
PLA thermoplastic filament
Metal powder
Laminated paper sheets
Subtractive manufacturing means
Adding layers of material
Removing material from a workpiece
Spraying material
Mixing powders
The energy source used in Selective Laser Sintering (SLS) is:
Ultrasonic waves
Focused laser beam
High-pressure gas jet
Plasma arc
Which is the first step in the RP process chain?
STL file generation
CAD modeling of the part
Post-processing
Slicing into layers
A common input for rapid prototyping is
STL file
BMP file
DOC file
DIX file
Which RP process is most suitable for thermoplastic prototypes?
SLA
SSM
LOM
FDM
Rapid tooling refers to
Fabrication of plastic components
Production of tools or moulds using RP methods
Preparation of design models in CAD software
Manufacturing of parts through CNC machining
In fused deposition modeling (FDM), support structures are usually made of
Photopolymer resin
A dissolvable secondary material
Metal powders
The same thermoplastic material
In Selective Laser Sintering (SLS)
Liquid resin is cured by laser
Paper sheets are glued together
Filament is extruded through a nozzle
Powder is fused together by laser energy
In stereolithography, the part is built inside a
Powder bed chamber
Liquid photopolymer vat
Metal deposition chamber
Lamination station
In RP, support structures are mainly required for
Parts made of metals only
All 2D models
Overhanging and complex geometries
Machined surfaces
The resolution and accuracy of an RP part depend primarily on
Layer thickness
Machine color
Tool sharpness
Cutting speed
Process of converting STL file model into layers is called in RP
Slicing
Chopping
Cutting
Trimming
STL file format is represented by interaction of
Lines and hexagons
Lines and rectangles
Lines and triangles
Lines and circles
What is the full name of SLS?
Selective Laser Simulator
Sintering Laser Simulator
Selective Laser Sintering
Stereolithography Laser Sintering
The primary raw material for SLA is
Metal powder
Thermoplastic filament
Photopolymer resin
Paper sheets
The principle of stereolithography (SLA) is
Melting filament with heat
Using UV laser to cure liquid resin
Jetting binder onto powder
Electron beam melting
Additive manufacturing builds a part
By cutting layers from a block
By removing unwanted material
By adding material layer by layer
By forging and casting
Which of the following is an additive manufacturing process?
Turning
Milling
Drilling
3D Printing
