100+ Diploma Trainee Engineer Interview Questions and Answers for Freshers

A jig is a tool used to guide and control the movement of a cutting tool, while a fixture is used to hold and position a workpiece during machining.

• Jigs are used to guide the cutting tool, while fixtures hold the workpiece.

• Jigs are used in drilling, reaming, and tapping operations, while fixtures are used in milling, grinding, and turning operations.

• Jigs are often custom-made for specific operations, while fixtures can be standardized and reused.

• Jigs are typically more comple...read more

Moulding is a manufacturing process of shaping liquid or pliable raw material using a rigid frame called a mold.

• Types of moulding: injection moulding, blow moulding, compression moulding, rotational moulding, etc.

• Forging is a manufacturing process of shaping metal using compressive forces.

• LPDC stands for Low Pressure Die Casting, a casting process for producing metal parts.

• Materials used for moulding: plastic, rubber, metal, glass, etc.

AC can be converted to DC using a rectifier circuit. The circuit diagram includes a transformer, diodes, and a filter capacitor.

• AC to DC conversion is achieved using a rectifier circuit.

• A rectifier circuit consists of a transformer, diodes, and a filter capacitor.

• The transformer steps down the AC voltage to a lower level.

• Diodes are used to convert the AC voltage to pulsating DC.

• The filter capacitor smoothens the pulsating DC to obtain a steady DC output.

• The circuit diagram ca...read more

Rectifier, types of motor, difference between servo motor and induction motor

• Rectifier is an electrical device that converts alternating current (AC) to direct current (DC)

• Types of motors include DC motors, AC motors, servo motors, and induction motors

• Servo motors are used in applications that require precise control of position, velocity, and acceleration

• Induction motors are commonly used in industrial applications due to their robustness and simplicity

• Difference between ser...read more

Major specifications to consider when buying an AC include cooling capacity, energy efficiency, noise level, and brand reputation.

• Cooling capacity measured in BTUs or tons

• Energy efficiency rating like EER or SEER

• Noise level in decibels

• Brand reputation for reliability and customer service

Backward stroke is the return stroke of the ram in shaping machine, while forward stroke is the cutting stroke.

• Backward stroke is when the ram moves away from the workpiece

• Forward stroke is when the ram moves towards the workpiece to make the cut

• Backward stroke is non-cutting, while forward stroke is cutting

• Backward stroke allows the tool to clear the workpiece, while forward stroke performs the cutting operation

List of technical questions for Diploma Engineer Trainee

• What is the difference between AC and DC current?

• Explain the working of a transformer.

• What is the purpose of a capacitor?

• What is the difference between a diode and a transistor?

• Explain the working of a 4-stroke engine.

• What is the function of a clutch in a manual transmission?

• What is the difference between a hub and a switch in networking?

• Explain the OSI model.

• What is the difference between a compiler and an interpreter?

• W...read more

A resistor is an electronic component that limits the flow of electric current in a circuit.

• Resistors are used to control the amount of current flowing through a circuit.

• They are passive components that dissipate energy in the form of heat.

• Resistors are measured in ohms (Ω) and have color-coded bands to indicate their resistance value.

• They can be fixed resistors with a specific resistance value or variable resistors that can be adjusted.

• Resistors are commonly used in voltage ...read more

Commercial and domestic voltage varies depending on the country and region.

• Commercial voltage is typically higher than domestic voltage.

• In the United States, commercial voltage is usually 120/208 volts or 277/480 volts.

• In residential areas of the United States, domestic voltage is typically 120/240 volts.

• In Europe, commercial voltage is often 230/400 volts, while domestic voltage is 230 volts.

• Frequency of supply voltage is usually 50 or 60 Hz, depending on the country.

Steam in a boiler is generated by heating water to its boiling point. There are various types of boilers, such as fire tube, water tube, and electric boilers.

• Boilers generate steam by heating water to its boiling point

• Types of boilers include fire tube, water tube, and electric boilers

• Fire tube boilers have hot gases flowing through tubes that are surrounded by water

• Water tube boilers have water flowing through tubes that are heated by combustion gases

• Electric boilers use ele...read more

The micrometre least count formula is the ratio of the pitch of the screw gauge to the number of divisions on the circular scale.

• The formula is LC = Pitch / Number of divisions on circular scale

• LC stands for least count

• Pitch is the distance moved by the spindle per revolution

• The number of divisions on the circular scale is the number of equally spaced divisions on the circular scale

• The formula is used to calculate the smallest measurement that can be made with a screw gauge

• Fo...read more

Vernier caliper diagram is used to understand the parts and functioning of the instrument.

• The diagram helps in identifying the main scale, vernier scale, jaws, depth gauge, and locking screw.

• It also shows how to read the measurements accurately using the vernier scale.

• The diagram is useful for beginners who are learning to use the vernier caliper.

• It is also helpful for troubleshooting and maintenance purposes.

• For example, if the jaws are not closing properly, the diagram can ...read more

The best manufacturing process depends on the product being manufactured and its requirements.

• Each manufacturing process has its own advantages and disadvantages.

• For example, injection molding is best for mass production of small and complex parts, while CNC machining is better for low-volume production of larger parts.

• The choice of manufacturing process also depends on factors such as cost, time, and quality requirements.

• Therefore, it is important to analyze the product and ...read more

I chose mechanical engineering because of my interest in machines and mechanisms. I have knowledge of engines, boilers, and computer skills.

• I have always been fascinated by how machines work and how they can be improved.

• Mechanical engineering offers a wide range of career opportunities in various industries.

• I have studied the principles of mechanics, thermodynamics, and materials science.

• An engine is a machine that converts fuel into mechanical energy to power vehicles or mac...read more

The second law of thermodynamics states that the total entropy of a closed system always increases over time.

• Entropy of a system tends to increase over time

• Heat cannot spontaneously flow from a colder location to a hotter location

• Efficiency of a heat engine is always less than 100%

• Entropy of the universe is always increasing

First law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted. Second law states that entropy of an isolated system always increases over time.

• First law is also known as law of conservation of energy

• Second law explains why heat flows from hot to cold objects

• Second law also states that no engine can be 100% efficient

• Entropy is a measure of disorder in a system

• Both laws are fundamental to understanding energy and its transformation...read more

Unit operations and unit processes are fundamental concepts in chemical engineering.

• Unit operations are physical processes such as filtration, distillation, and evaporation that are used to separate or transform materials.

• Unit processes are chemical reactions or biological processes that are used to transform raw materials into desired products.

• Unit operations and unit processes are often combined in chemical engineering to create a complete production process.

• Examples of uni...read more

A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction.

• Transformers are used to increase or decrease the voltage levels in electrical power transmission and distribution systems.

• They consist of two or more coils of wire, known as windings, which are wound around a core made of magnetic material.

• The primary winding is connected to the input voltage source, while the secondary winding is connected to...read more

Air is interned in the combustion chamber during the intake stroke.

• During the intake stroke, the piston moves down and air is drawn into the combustion chamber.

• This air is then mixed with fuel and ignited during the compression stroke.

• The resulting explosion pushes the piston down, which drives the crankshaft and produces power.

• The exhaust stroke then expels the spent gases from the combustion chamber.

• This four-stroke cycle is repeated continuously to power the engine.

Two stroke engines have one power stroke per revolution while four stroke engines have one power stroke every two revolutions.

• Two stroke engines have a simpler design and are lighter than four stroke engines.

• Four stroke engines are more fuel efficient and produce less emissions than two stroke engines.

• Two stroke engines are commonly used in small power tools and motorcycles while four stroke engines are used in cars and larger machinery.

• Two stroke engines require a mixture of...read more

A 7 sided shape is called a heptagon.

• A heptagon has 7 sides and 7 angles.

• All the angles of a heptagon add up to 900 degrees.

• Examples of heptagons include stop signs and some coins.

Induction motor works on the principle of electromagnetic induction to convert electrical energy into mechanical energy.

• Induction motor has a stator and a rotor

• Stator has a set of coils that are supplied with AC current

• This creates a rotating magnetic field which induces current in the rotor

• The rotor then starts rotating due to interaction with the magnetic field

• Induction motor is widely used in industries for various applications

Enthalpy is a thermodynamic property that represents the total heat content of a system.

• Enthalpy is denoted by the symbol H.

• It is defined as the sum of the internal energy of a system and the product of its pressure and volume.

• The formula for enthalpy is H = U + PV, where U is the internal energy, P is the pressure, and V is the volume.

• Enthalpy is often used in chemical reactions to measure the heat exchanged with the surroundings.

• It can be used to calculate the heat absorbed...read more

The project planning and execution went well, resulting in meeting deadlines and achieving project goals.

• Effective communication among team members

• Proper allocation of resources

• Regular monitoring and tracking of progress

• Adaptability to changes in project requirements

The first priority in Cummins is customer satisfaction.

• Customer satisfaction is the top priority for Cummins.

• Providing high-quality products and services to meet customer needs.

• Building strong relationships with customers and exceeding their expectations.

• Ensuring prompt and effective customer support and after-sales service.

• Continuous improvement and innovation to deliver value to customers.

There are three types of heat transfer: conduction, convection, and radiation.

• Conduction is the transfer of heat through direct contact between solids.

• Convection is the transfer of heat through the movement of fluids (liquids or gases).

• Radiation is the transfer of heat through electromagnetic waves.

• Examples: Conduction - touching a hot stove; Convection - boiling water; Radiation - feeling the warmth of the sun.

2D diagrams are flat while 3D diagrams have depth and volume.

• 2D diagrams are represented on a flat surface while 3D diagrams have depth and volume.

• 2D diagrams are used to represent objects or structures in a two-dimensional plane while 3D diagrams are used to represent objects or structures in a three-dimensional space.

• 2D diagrams are commonly used in engineering drawings, architectural plans, and circuit diagrams while 3D diagrams are used in computer graphics, video games, ...read more

My future planning for new technology is to stay updated with the latest advancements and incorporate them into my work.

• Continuously learning about new technologies through research and attending conferences

• Collaborating with colleagues to implement new technologies in projects

• Experimenting with new technologies in personal projects

• Staying up-to-date with industry trends and advancements

The 1/3 of 100 & 78 is 59.33

• To find 1/3 of a number, divide it by 3

• 1/3 of 100 = 100/3 = 33.33

• 1/3 of 78 = 78/3 = 26

• The average of 33.33 and 26 is 59.33

Designing a shaft involves considering factors like material selection, dimensions, and load capacity.

• Determine the purpose and function of the shaft

• Select an appropriate material based on factors like strength, corrosion resistance, and cost

• Calculate the required dimensions and tolerances based on the load and operating conditions

• Consider factors like shaft alignment, balancing, and lubrication

• Perform stress analysis to ensure the shaft can withstand the applied loads

• Conside...read more

DM plant equipment includes ion exchange resin beds, reverse osmosis units, and mixed bed exchangers. Coal handling plant equipment includes crushers, conveyors, and stacker reclaimers.

• DM plant equipment: ion exchange resin beds, reverse osmosis units, mixed bed exchangers

• Coal handling plant equipment: crushers, conveyors, stacker reclaimers

• Demineralised water used in boiler to prevent scaling and corrosion

• High mineral content in water can lead to boiler inefficiency and dama...read more

Micrometre is a unit of measurement for length, while snap gauge is a tool used to measure the thickness or diameter of an object.

• Micrometre is also known as a micron and is equal to one-millionth of a meter.

• Snap gauge is used in manufacturing to ensure the accuracy of machined parts.

• Snap gauge can be used to measure the thickness of paper, the diameter of a wire, or the width of a gap.

• Both micrometre and snap gauge are commonly used in engineering and manufacturing industrie...read more

Different types of logic gates are used in digital circuits to perform different logical operations based on input signals.

• There are basic logic gates like AND, OR, NOT, NAND, NOR, XOR, and XNOR.

• Each gate has a specific truth table that defines the output based on the input combinations.

• For example, an AND gate outputs 1 only when both inputs are 1.

• A NOT gate outputs the inverse of the input signal.

• Combining these gates in different configurations allows for complex logic ope...read more

Two stroke and four stroke engines are types of internal combustion engines used in vehicles and machinery.

• Two stroke engines complete a power cycle in two strokes of the piston, while four stroke engines complete it in four strokes.

• Two stroke engines have a simpler design and are lighter, but are less fuel efficient and emit more pollutants.

• Four stroke engines are more complex but offer better fuel efficiency and lower emissions.

• Examples of vehicles that use two stroke engin...read more

Vernier caliper is a precision measuring tool used to measure length, diameter, depth, and thickness.

• Clean the measuring surfaces before use

• Close the jaws and check if the zero mark on the vernier scale aligns with the zero mark on the main scale

• Place the object to be measured between the jaws and tighten the lock screw

• Read the measurement from the main scale and the vernier scale

• Add the two readings to get the final measurement

• Use the depth gauge to measure the depth of hole...read more

The tolerance between gear teeth in meshed gears is crucial for smooth operation and preventing damage.

• Tolerance between gear teeth is typically specified in terms of backlash, which is the amount of clearance between the meshing teeth.

• The tolerance depends on the application and the type of gears being used.

• For example, in high precision applications like aerospace or automotive transmissions, the tolerance is very tight to ensure smooth operation.

• In contrast, in less critic...read more

A DOL starter control and power circuit is used to start and stop a motor directly on full line voltage.

• DOL stands for Direct-On-Line.

• The control circuit consists of a start button, stop button, and overload relay.

• The power circuit includes a contactor, motor, and power supply.

• When the start button is pressed, the contactor closes and the motor starts.

• The overload relay protects the motor from excessive current.

• The stop button opens the contactor and stops the motor.

Electricity in power plants is generated through various methods like burning fossil fuels, nuclear reactions, or harnessing renewable sources like wind or solar.

• Burning fossil fuels like coal, oil, or natural gas to heat water and produce steam to turn turbines

• Nuclear reactions in nuclear power plants to generate heat and produce steam

• Harnessing renewable sources like wind turbines or solar panels to convert natural energy into electricity

PLC stands for Programmable Logic Controller. It is an industrial computer used to automate processes.

• PLCs are used to control and monitor industrial processes such as assembly lines, power plants, and water treatment facilities.

• They are programmed using ladder logic or other programming languages.

• PLCs can be used to control various types of equipment such as motors, valves, and sensors.

• They are designed to operate in harsh environments and can withstand extreme temperatures,...read more

Time wasted on unnecessary meetings is the biggest waste in my perspective.

• Unproductive meetings can waste valuable time and resources

• Lack of clear agenda or goals can lead to aimless discussions

• Effective communication and planning can help reduce wasted time in meetings

Gear tooth vernier caliper is a measuring tool used to measure the thickness of gear teeth.

• It is a specialized type of vernier caliper used in gear manufacturing.

• It has two jaws, one of which is pointed to fit into the gear tooth space.

• The other jaw is flat and used to measure the thickness of the gear tooth.

• It is used to ensure the accuracy of gear teeth dimensions.

• Examples of gear tooth vernier calipers include Mitutoyo 505-742 and Starrett 782.

Sensors are devices that detect and respond to physical stimuli and convert them into electrical signals.

• There are various types of sensors such as temperature sensors, pressure sensors, proximity sensors, motion sensors, light sensors, etc.

• Temperature sensors measure the temperature of an object or environment and include thermocouples, RTDs, and thermistors.

• Pressure sensors measure the pressure of gases or liquids and include piezoresistive, capacitive, and piezoelectric se...read more

Positive displacement pumps move fluid by trapping a fixed amount and forcing it through the discharge pipe, while non-positive displacement pumps use centrifugal force to move fluid.

• Positive displacement pumps have a constant flow rate regardless of discharge pressure.

• Examples of positive displacement pumps include gear pumps, piston pumps, and diaphragm pumps.

• Non-positive displacement pumps have a variable flow rate depending on discharge pressure.

• Examples of non-positive d...read more

Safety is the state of being protected from harm or danger. The process of accident involves a series of events leading to an unplanned and undesirable outcome.

• Safety involves identifying and assessing potential hazards and taking measures to prevent them

• Accidents can be caused by human error, equipment failure, or environmental factors

• The process of accident involves a sequence of events including the occurrence of a hazard, exposure to the hazard, and the resulting harm or ...read more

The least count of a Vernier caliper is the smallest measurement that can be accurately read.

• The least count is determined by the number of divisions on the main scale and the Vernier scale.

• It is calculated by dividing the smallest division on the main scale by the total number of divisions on the Vernier scale.

• For example, if the smallest division on the main scale is 0.1 mm and the Vernier scale has 10 divisions, the least count would be 0.01 mm.

• The least count represents t...read more

A petrol engine is an internal combustion engine that uses petrol as fuel to power the vehicle.

• Petrol engines are commonly used in cars, motorcycles, and small aircraft.

• They work by compressing a mixture of petrol and air in a cylinder, which is then ignited by a spark plug.

• The resulting explosion pushes a piston, which turns a crankshaft and powers the vehicle.

• Petrol engines are known for their high power output and quick acceleration.

• However, they are less fuel-efficient th...read more

Project work is a collaborative effort aimed at achieving specific goals within a set timeframe.

• Project work involves planning, executing, and monitoring tasks to achieve desired outcomes.

• It often requires teamwork, effective communication, and time management skills.

• Examples include developing a new product, conducting research, or implementing a new system.