200+ Diploma Mechanical Engineer Interview Questions and Answers

The second law of thermodynamics states that the entropy of an isolated system always increases over time.

• Entropy of an isolated system always increases

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

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

• Examples: melting ice, burning wood

Thermodynamics, stress and strain determination, manufacturing processes, CAD software proficiency, IC engine operation, Otto cycle explanation

• Basic principles of thermodynamics involve energy transfer and conversion, entropy, and the laws of thermodynamics

• Stress in a material is determined by dividing the applied force by the cross-sectional area, while strain is the ratio of the change in length to the original length

• Types of manufacturing processes include casting, machini...read more

Pumps are devices used to move fluids from one place to another. They are classified based on their working principle and application.

• Pumps can be classified as positive displacement pumps and dynamic pumps.

• Positive displacement pumps move a fixed amount of fluid with each stroke or rotation. Examples include reciprocating pumps and rotary pumps.

• Dynamic pumps use velocity to move fluids. Examples include centrifugal pumps and axial flow pumps.

• Pumps can also be classified base...read more

Surge tank

• A surge tank is used to protect the penstock from sudden variations in flow or velocity of water.

• It absorbs the excess pressure caused by sudden changes in flow and prevents damage to the penstock.

• Surge tanks are typically installed in hydropower plants and water distribution systems.

• They help maintain a steady flow of water and prevent water hammer effects.

• Examples of surge tanks include open surge tanks, closed surge tanks, and standpipe surge tanks.

Excel is a spreadsheet program used for data analysis and MLA stands for Modern Language Association.

• Excel is a software application developed by Microsoft that allows users to create, organize, and analyze data using spreadsheets.

• MLA is a style guide used for writing and documenting research papers in the fields of humanities and liberal arts.

• ASALI and Emily are not related to Excel or MLA. It seems like there might be a misunderstanding or miscommunication in the question.

The 4 main components of material science are structure, properties, processing, and performance.

• Structure: The arrangement of atoms and molecules in a material.

• Properties: The characteristics of a material, such as strength, hardness, and conductivity.

• Processing: The methods used to shape and form materials, like casting, forging, and machining.

• Performance: How a material behaves under specific conditions, including its durability and reliability.

Benson Boiler is a type of boiler that does not require a steam drum.

• Benson Boiler is a high-pressure, water tube boiler.

• It operates at supercritical pressure.

• The water is heated in a single pass through the evaporator tubes.

• It is commonly used in power plants.

• Examples include the Lethabo, Majuba, and Kendal power stations in South Africa.

I would assess the situation to determine the cause of the deviation and take corrective actions to bring the target back to 100.

• Investigate the reason for the deviation from the target

• Identify any external factors affecting the target

• Implement corrective measures to bring the target back to 100

• Monitor the progress closely to ensure the target is achieved

Yes, there are many types of valves including ball, gate, globe, butterfly, check, and needle valves.

• Valves are used to control the flow of fluids or gases in a system.

• Ball valves have a spherical closure unit that allows for quick shut-off.

• Gate valves have a flat closure unit that slides into place to stop flow.

• Globe valves have a spherical closure unit that moves up and down to regulate flow.

• Butterfly valves have a disc-shaped closure unit that rotates to control flow.

• Check...read more

The hydro test pressure of an equipment connection is the pressure at which the connection is tested for leaks and strength.

• Hydro test pressure is determined based on the design and operating conditions of the equipment.

• It is usually expressed in units of pressure, such as psi or bar.

• The test pressure should be higher than the maximum operating pressure to ensure the connection's integrity.

• The test pressure may vary depending on the type of equipment and its intended use.

• For ...read more

Shaft balancing in accordance with ISO 21940-11 and ISO 21940-12 standards involves reducing vibrations by adjusting the mass distribution along the shaft.

• Shaft balancing aims to minimize vibrations in rotating machinery by adjusting the mass distribution along the shaft.

• ISO 21940-11 specifies the balancing process for rigid rotors, while ISO 21940-12 covers the balancing of flexible rotors.

• Balancing involves adding or removing weight from specific locations on the shaft to a...read more

A car's wheel and axle system is a simple machine that allows the car to move efficiently.

• The wheel and axle system consists of a wheel (the round part) attached to an axle (the rod that goes through the center of the wheel).

• When the axle rotates, it causes the wheel to turn, allowing the car to move forward or backward.

• The wheel and axle system reduces friction and makes it easier for the car to move.

• An example of a wheel and axle system in a car is the wheels attached to th...read more

Investigate the root cause of the deviation and take corrective actions to ensure the target is met in future shifts.

• Analyze the production process to identify any bottlenecks or inefficiencies causing the deviation.

• Check if there were any machine breakdowns or maintenance issues affecting the production output.

• Review the raw material quality and availability to ensure they meet the required standards.

• Evaluate the performance of the workforce to see if additional training or ...read more

An engine is a machine that converts fuel into mechanical energy to power a vehicle or machinery.

• Engines come in various types such as internal combustion, diesel, electric, and hybrid.

• They are used in cars, trucks, airplanes, boats, and generators.

• The engine consists of various components such as cylinders, pistons, crankshaft, and camshaft.

• The engine's power output is measured in horsepower or kilowatts.

• Regular maintenance is required to keep the engine running efficiently.

Setting up belt conveyors, rollers, and gearboxes involves proper alignment, tensioning, and lubrication.

• Ensure proper alignment of the belt conveyor, rollers, and gearboxes to prevent misalignment issues.

• Tension the belt properly to ensure it is not too loose or too tight, which can affect the conveyor's performance.

• Regularly lubricate the rollers and gearboxes to reduce friction and prevent wear and tear.

• Check for any signs of damage or wear on the belt, rollers, and gearbo...read more

I will analyze my performance, identify areas for improvement, and create a plan to reach the target of 100.

• Analyze the reasons for not reaching the target score of 100

• Identify areas for improvement such as time management, study habits, or understanding of the material

• Create a plan with specific goals and actions to improve performance

• Seek feedback from teachers or mentors for guidance and support

Machines are mechanical devices that use energy to perform tasks. Gears are mechanical components that transmit power and motion.

• Machines are used to make work easier by using energy to perform tasks

• Mechanical engineering involves designing, analyzing, and manufacturing machines and mechanical systems

• Gears are mechanical components that transmit power and motion between rotating shafts

• They are used in many machines, such as cars, bicycles, and industrial equipment

• Different ty...read more

The number of manpower needed for a 1 MW site in one day completion depends on various factors such as the complexity of the project, equipment availability, and skill level of the workers.

• Number of manpower required will vary based on the type of work (installation, maintenance, etc.)

• Availability of equipment like cranes, trucks, and tools will impact manpower needs

• Skill level of workers will determine efficiency and speed of work

• For example, a simple installation project ma...read more

The least count of a measuring instrument is the smallest value that can be measured with it.

• The least count of a vernier caliper is typically 0.02 mm.

• The least count of a micrometer is typically 0.01 mm.

• The least count of a steam turbine depends on the specific turbine and its design.

CC stands for Carbon Copy, which is a copy of a document made by using carbon paper.

• CC is used to make a duplicate copy of a document without the need for a photocopier or printer.

• Carbon paper is placed between the original document and the copy paper, and pressure is applied to transfer the ink.

• CC is commonly used in offices for making copies of letters, invoices, and other documents.

• It is also used in art for transferring sketches or designs onto different surfaces.

• CC can a...read more

Propeller shaft transmits power from engine to the wheels of a vehicle.

• It connects the transmission to the rear axle.

• It rotates at high speeds and needs to be balanced.

• It may have universal joints to allow for suspension movement.

• It may have a slip joint to allow for changes in length due to suspension movement.

• It may be made of steel or aluminum depending on the application.

If there is a defect in the product, it is important to identify the root cause, rectify the issue, and implement preventive measures.

• Identify the root cause of the defect through thorough analysis and testing

• Rectify the issue by repairing or replacing the defective parts

• Implement preventive measures to avoid similar defects in the future, such as improving quality control processes or training staff

• Communicate with relevant stakeholders about the defect and the steps taken t...read more

Piston rings are components in an engine that seal the combustion chamber and prevent leakage of gases.

• Piston rings are circular metal rings that fit into grooves on the outer diameter of the piston.

• They provide a seal between the piston and the cylinder wall, preventing the combustion gases from leaking into the crankcase.

• Piston rings also help to regulate the oil distribution on the cylinder walls, ensuring proper lubrication.

• They assist in transferring heat from the piston...read more

Various types of brakes include disc brakes, drum brakes, regenerative brakes, electromagnetic brakes, and hydraulic brakes.

• Disc brakes use calipers to squeeze brake pads against a rotor to slow or stop the vehicle.

• Drum brakes use shoes that press against the inside of a drum to slow or stop the vehicle.

• Regenerative brakes convert kinetic energy into electrical energy to recharge the battery.

• Electromagnetic brakes use an electromagnetic field to create friction and slow or st...read more

Main parts of an IC engine include cylinder, piston, crankshaft, connecting rod, spark plug, and intake/exhaust valves.

• Cylinder: Houses the piston and combustion process

• Piston: Moves up and down in the cylinder to create power

• Crankshaft: Converts linear motion of the piston into rotational motion

• Connecting rod: Connects the piston to the crankshaft

• Spark plug: Ignites the air-fuel mixture in the cylinder

• Intake/exhaust valves: Control the flow of air-fuel mixture in and exhaust...read more

Ace and Refrigerate are two different terms and cannot be compared as they are not related.

• Ace is a term used to describe someone who is very skilled or proficient in a particular activity or subject.

• Refrigerate is a term used to describe the process of cooling or preserving food or other perishable items.

• Ace and Refrigerate are not related to each other and cannot be compared.

Parts of a vapour compression system

• Compressor

• Condenser

• Expansion valve

• Evaporator

• Refrigerant

• Piping

• Controls

Preparation for commissioning involves thorough testing, documentation, safety checks, and coordination.

• Ensure all equipment is installed correctly and functioning properly

• Conduct thorough testing to identify any issues or malfunctions

• Prepare detailed documentation of equipment specifications, procedures, and safety protocols

• Perform safety checks to ensure compliance with regulations and standards

• Coordinate with various teams and stakeholders for a smooth commissioning proces...read more

Different types of fit include clearance fit, interference fit, and transition fit.

• Clearance fit: parts are designed to have a gap between them, allowing for easy assembly and disassembly.

• Interference fit: parts are designed to be pressed or forced together, creating a tight and secure fit.

• Transition fit: parts have a small amount of overlap, creating a balance between clearance and interference fit.

• Examples include piston and cylinder in an engine, bearings in a machine, and...read more

Being a good mechanic has several benefits including job security, higher pay, and the ability to fix your own vehicles.

• Job security due to high demand for skilled mechanics

• Higher pay for experienced and knowledgeable mechanics

• Ability to fix your own vehicles and save money on repairs

• Opportunities for specialization in specific types of vehicles or systems

• Potential for entrepreneurship and owning your own repair shop

The worker should be provided with proper training and guidance to ensure awareness of the work.

• Provide comprehensive training sessions for the worker to understand the tasks and responsibilities.

• Assign a mentor or supervisor to guide the worker through the work processes.

• Encourage open communication and feedback to address any confusion or lack of understanding.

• Regularly assess the worker's progress and provide additional support if needed.

• Implement safety protocols to preve...read more

In the field, a Diploma Mechanical Engineer may be responsible for maintenance, repairs, and troubleshooting of mechanical systems. Breakdown refers to unexpected equipment failure, while shutdown is a planned cessation of operations for maintenance or repairs.

• Job duties may include maintenance, repairs, and troubleshooting of mechanical systems

• Breakdown is an unexpected equipment failure that requires immediate attention

• Shutdown is a planned cessation of operations for maint...read more

GMP documents ensure quality and compliance in manufacturing, covering processes, procedures, and standards in production.

• Standard Operating Procedures (SOPs): Detailed instructions on how to perform specific tasks, such as equipment operation or cleaning protocols.

• Batch Records: Documentation of each batch produced, including ingredients, processes, and quality checks to ensure traceability and compliance.

• Quality Control Records: Documents that outline testing methods and re...read more

Two-stroke engines have a power stroke every revolution, while four-stroke engines have a power stroke every other revolution.

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

• Two-stroke engines are commonly used in small power tools, motorcycles, and boats.

• Four-stroke engines are more fuel-efficient and have a longer lifespan than two-stroke engines.

• Four-stroke engines are commonly used in cars, trucks, and larger machinery.

A circular object that rotates around an axis and is used for transportation or machinery.

• A wheel is typically made of metal or rubber and can be found on vehicles such as cars, bicycles, and trucks.

• Wheels are also used in machinery such as conveyor belts and pulleys.

• The invention of the wheel is considered one of the most important inventions in human history.

• Wheels can come in different sizes and shapes depending on their intended use.

• The rotation of a wheel can be used to ...read more

An engine is a machine that converts fuel into motion. There are various types of engines such as internal combustion, steam, and electric.

• Types of engines include internal combustion, steam, electric, and gas turbine

• Examples of mechanical tools include wrenches, pliers, screwdrivers, hammers, and saws

• Moulding is a manufacturing process where a liquid or pliable material is poured into a mold and allowed to harden into a specific shape

Diploma mechanical engineers are responsible for designing, developing, and testing mechanical devices and systems.

• Designing mechanical components and systems

• Developing prototypes and conducting tests

• Collaborating with other engineers and professionals

• Ensuring compliance with industry standards and regulations

• Troubleshooting and resolving mechanical issues

CNC and VMC are advanced machining technologies used for precision manufacturing in various industries.

• CNC (Computer Numerical Control): CNC machines automate control of machining tools via computer programming, enhancing precision and efficiency.

• VMC (Vertical Machining Center): VMCs are CNC machines with a vertical spindle orientation, ideal for milling operations and complex part geometries.

• Applications: CNC and VMC are widely used in aerospace, automotive, and medical devi...read more

A centrifugal pump works by converting mechanical energy from a motor into kinetic energy in a fluid through the rotation of an impeller.

• Centrifugal pump uses an impeller to rotate and create a centrifugal force to push the fluid outward.

• The fluid enters the pump through the center of the impeller and is accelerated by the rotating blades.

• The kinetic energy of the fluid increases as it moves radially outward, creating pressure that forces the fluid out through the pump outlet...read more

The cam used in IC engine is a rotating or sliding piece in a machinery that imparts reciprocating motion to another part.

• Cam is used to convert rotary motion into reciprocating motion in an IC engine.

• It controls the opening and closing of valves in the engine.

• Examples of cams in IC engines include camshafts and cam followers.

A mechanism is a system of parts that work together to perform a specific function, while a reference is a source of information or guidance.

• A mechanism is a physical or mechanical device that enables motion or action.

• A reference can be a book, document, or person that provides information or guidance.

• Mechanisms are often used in machines to convert input energy into output motion or force.

• References are used to gather information or learn from the experiences and knowledge o...read more

The least measuring instruments used in the process are rulers and calipers.

• Rulers are used to measure length or distance.

• Calipers are used to measure the thickness or diameter of objects.

• Other possible least measuring instruments include tape measures and micrometers.

Milling machines cut materials using rotating tools, while lathes shape materials by rotating them against a stationary tool.

• Milling machines use rotary cutters to remove material, ideal for flat surfaces and complex shapes.

• Lathes rotate the workpiece against a fixed cutting tool, primarily used for cylindrical shapes.

• Milling can create slots, holes, and intricate designs; for example, creating gears or brackets.

• Lathes are used for turning operations, such as making shafts, s...read more

RTJ Lens Rings are used in flange connections to provide a seal and prevent leakage.

• RTJ Lens Rings are used in high-pressure and high-temperature applications.

• They are commonly used in industries such as oil and gas, petrochemical, and power generation.

• RTJ Lens Rings provide a reliable and secure seal between flanges, preventing leakage.

• They are designed to withstand extreme conditions and maintain their sealing properties over time.

• Examples of applications include pipeline c...read more

Petrol engines use spark ignition, while diesel engines use compression ignition.

• Petrol engines use a spark plug to ignite the fuel-air mixture, while diesel engines rely on compression to ignite the fuel.

• Petrol engines are lighter and more responsive, while diesel engines are more fuel efficient and have higher torque.

• Petrol engines are more common in cars and motorcycles, while diesel engines are often used in trucks, buses, and heavy machinery.

SAE stands for Society of Automotive Engineers, a global organization that develops standards for the automotive industry.

• SAE is a professional organization that was founded in 1905 and has over 138,000 members worldwide.

• SAE develops standards for the automotive, aerospace, and commercial vehicle industries.

• Examples of SAE standards include specifications for engine oil, fuel, and hydraulic fluids.

• SAE also hosts events and competitions for engineering students, such as the Fo...read more

Universal coupling is a mechanical device used to connect two shafts at an angle and transmit torque.

• Universal coupling is also known as a universal joint or U-joint.

• It consists of two yokes connected by a cross-shaped member called a spider.

• The spider allows the two yokes to rotate independently of each other while transmitting torque.

• Universal couplings are commonly used in automotive drive shafts to accommodate misalignment and allow for smooth power transmission.

• They are ...read more