700+ Maintenance Engineer Interview Questions and Answers

Temperature rise of hydraulic oil in die casting machine is caused by friction, overloading, inadequate cooling, or contaminated oil.

• Friction between moving parts can generate heat and increase oil temperature

• Overloading the machine can cause excessive heat generation

• Inadequate cooling system or malfunctioning cooling components can lead to temperature rise

• Contaminated oil with debris or moisture can reduce lubrication efficiency and increase friction

Up milling and down milling are two types of milling operations used in machining.

• Up milling is also known as conventional milling, where the cutter rotates against the direction of feed.

• Down milling is also known as climb milling, where the cutter rotates in the same direction as the feed.

• Up milling produces a rougher surface finish and generates more heat, while down milling produces a smoother surface finish and generates less heat.

• Up milling is preferred for tough materia...read more

Boilers are classified based on their design, fuel type, and application.

• Fire-tube boilers

• Water-tube boilers

• Electric boilers

• Gas boilers

• Oil boilers

• Solid fuel boilers

• Combination boilers

• Condensing boilers

• Industrial boilers

• Residential boilers

Colour coding on three phase supply RYB is used for easy identification and proper connection of phases.

• Colour coding helps in identifying different phases easily

• Prevents incorrect connections which can lead to equipment damage or accidents

• Standardizes the wiring system for consistency and safety

• Red phase (R), Yellow phase (Y), Blue phase (B) are commonly used for RYB colour coding

There are 5 flags in 8085 microprocessor - Carry, Auxiliary Carry, Sign, Zero, and Parity.

• 8085 microprocessor has 5 flags

• Carry flag is set when there is a carry out of the MSB in an arithmetic operation

• Auxiliary Carry flag is set when there is a carry out of bit 3 in an arithmetic operation

• Sign flag is set when the result of an operation is negative

• Zero flag is set when the result of an operation is zero

• Parity flag is set when the result of an operation has even number of 1s ...read more

The number of points in a PM checklist varies depending on the equipment being checked.

• PM checklists are specific to each piece of equipment.

• The number of points in a PM checklist can range from a few to hundreds.

• Points in a PM checklist can include tasks such as inspecting, cleaning, and lubricating equipment.

• The purpose of a PM checklist is to ensure that equipment is properly maintained and to prevent breakdowns.

• The number of points in a PM checklist can be adjusted based ...read more

To check ball screw backlash, turret alignment, spindle run out, and ATC alignment, follow these steps:

• For ball screw backlash, use a dial indicator to measure the amount of play in the screw

• For turret alignment, use a test bar to check the alignment of the turret with the spindle axis

• For spindle run out, use a dial indicator to measure the amount of deviation in the spindle rotation

• For ATC alignment, use a test bar to check the alignment of the tool changer with the spindle ...read more

Mounting and demounting methods of a bearing involve using various tools and techniques to properly install and remove the bearing from its housing.

• Mounting methods include press fitting, heating, and using specialized tools like bearing pullers

• Demounting methods involve using bearing pullers, hydraulic presses, or heating to expand the housing

• Proper alignment and lubrication are crucial for successful mounting and demounting

• Examples of mounting tools include bearing heaters,...read more

LMTD stands for Logarithmic Mean Temperature Difference and is used to calculate the temperature difference in a heat exchanger.

• LMTD is a method used to determine the temperature difference between two fluids in a heat exchanger

• It takes into account the temperature difference at different points along the length of the heat exchanger

• LMTD is used to calculate the heat transfer rate in a heat exchanger

• It is calculated using the formula LMTD = (ΔT1 - ΔT2) / ln(ΔT1 / ΔT2)

• LMTD is ...read more

Water chiller maintenance involves regular cleaning, inspection, and servicing to ensure optimal performance and prevent breakdowns.

• Regularly clean the condenser and evaporator coils to remove dirt and debris

• Check refrigerant levels and top up if necessary

• Inspect and replace filters as needed

• Check for leaks and repair any damaged components

• Schedule routine maintenance with a qualified technician

• Keep a maintenance log to track service history and identify trends

A motor is a device that converts electrical energy into mechanical energy, used in various applications.

• Types of motors include AC motors, DC motors, and stepper motors.

• AC motors are commonly used in household appliances like fans and refrigerators.

• DC motors are often found in toys, electric vehicles, and small machinery.

• Stepper motors are used in precision applications like 3D printers and CNC machines.

Maintenance ensures equipment reliability through various strategies to prevent failures and extend lifespan.

• Preventive Maintenance: Regular inspections and servicing to prevent breakdowns (e.g., oil changes in vehicles).

• Corrective Maintenance: Repairs made after a failure occurs (e.g., fixing a broken conveyor belt).

• Predictive Maintenance: Using data and analytics to predict when maintenance should be performed (e.g., vibration analysis in machinery).

• Routine Maintenance: Sch...read more

SMPS stands for Switched Mode Power Supply. It is an electronic power supply that efficiently converts electrical power.

• SMPS is a type of power supply that uses switching regulators to convert electrical power.

• It is commonly used in electronic devices such as computers, televisions, and mobile phones.

• SMPS operates by rapidly switching the input voltage on and off to regulate the output voltage.

• It provides a more efficient and compact solution compared to traditional linear po...read more

Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it, given a constant resistance.

• Ohm's Law: V = I * R (Voltage = Current * Resistance)

• Current is directly proportional to Voltage when Resistance is constant

• Higher voltage leads to higher current flow, and vice versa

• Lower resistance leads to higher current flow, and vice versa

• Example: If a circuit has a voltage of 12V and a resistance of 4 ohms, the current flow...read more

To connect the CCTV network from SCR to TER, you need to establish a physical connection between the two locations and configure the network settings accordingly.

• Ensure there is a direct physical connection (such as Ethernet cable) between the SCR and TER locations.

• Configure the network settings on both ends to ensure they are on the same network and can communicate with each other.

• Test the connection to ensure the CCTV network is successfully connected from SCR to TER.

There are various types of motors, welding methods, heating techniques, and power factors in engineering.

• Types of motors include AC motors (induction, synchronous), DC motors (brushed, brushless), stepper motors, etc.

• Types of welding include arc welding, MIG welding, TIG welding, spot welding, etc.

• Types of heating methods include conduction, convection, radiation, induction heating, etc.

• Power factor types include leading power factor, lagging power factor, unity power factor,...read more

1kcal is the amount of energy required to raise the temperature of 1 kilogram of water by 1 degree Celsius.

• 1kcal is a unit of energy measurement.

• It is commonly used to measure the energy content of food.

• 1kcal is equal to 1000 calories.

• Calories are a measure of the amount of energy in food.

• The energy content of food is usually measured in kilocalories (kcal) or kilojoules (kJ).

To troubleshoot a recurring problem in equipment, I would follow a systematic approach to identify the root cause and implement a permanent solution.

• Start by gathering information about the problem, including when it occurs and any patterns or common factors.

• Inspect the equipment thoroughly to identify any visible signs of damage or wear.

• Review maintenance records and previous repair attempts to see if there is a recurring issue that has not been fully resolved.

• Use diagnostic...read more

Oil can float on water despite having a higher density due to differences in molecular structure and polarity.

• Oil molecules are non-polar and do not form strong interactions with water molecules

• Water molecules are polar and form hydrogen bonds, causing them to stick together and create a denser structure

• The difference in polarity and molecular structure allows oil to float on water

This question covers properties of air, generation of CO2 gas, and its applications.

• Air is a mixture of gases, primarily nitrogen and oxygen

• CO2 gas is generated through combustion of fossil fuels, fermentation, and respiration

• CO2 gas is used in fire extinguishers, carbonation of beverages, and as a refrigerant

Identify root causes, implement preventive measures, and ensure proper maintenance to resolve recurring machine issues.

• Conduct a root cause analysis to identify underlying issues. For example, if a motor frequently fails, check for electrical imbalances.

• Implement preventive maintenance schedules to address wear and tear before it leads to failures. For instance, lubricate moving parts regularly.

• Train operators on proper machine usage to minimize user-induced errors. For examp...read more

Current can be measured using an ammeter, which measures the flow of electric charge in a circuit.

• Use an ammeter to measure current

• Connect the ammeter in series with the circuit

• Ensure the ammeter is set to the appropriate range for the expected current

• Read the current value displayed on the ammeter

• Example: To measure the current flowing through a light bulb, connect the ammeter in series with the bulb and read the displayed value

A CNC machine can have 3, 4, or 5 axes depending on its configuration.

• The X, Y, and Z axes are common in 3-axis machines.

• 4-axis machines add a rotary axis, usually the A-axis.

• 5-axis machines add a second rotary axis, usually the B-axis.

• Some machines may have additional axes for specialized operations, such as milling machines with a tilting spindle head.

• The number of axes determines the machine's capabilities and the complexity of its programming.

Types of sand used in casting include green sand, resin sand, shell mold sand, and sodium silicate sand.

• Green sand: most commonly used type, made of silica sand mixed with clay and water

• Resin sand: mixed with resin and hardener for better surface finish and dimensional accuracy

• Shell mold sand: uses a resin-coated sand that is heated to form a shell around the pattern

• Sodium silicate sand: uses sodium silicate as a binder, good for large castings and high-temperature applicatio...read more

Initiating the planning process involves assessing needs, gathering data, and setting clear objectives for maintenance tasks.

• Conduct a thorough assessment of current equipment and systems to identify maintenance needs.

• Gather historical data on equipment performance and maintenance records to inform planning.

• Engage with stakeholders, including operators and management, to understand their concerns and priorities.

• Set clear objectives for the maintenance plan, such as reducing d...read more

I have worked on machines with various geometries, including cylindrical, rectangular, and spherical shapes.

• Worked on machines with cylindrical geometry, such as lathes and milling machines.

• Handled machines with rectangular geometry, like conveyor belts and packaging equipment.

• Dealt with machines with spherical geometry, such as ball bearings and rotary valves.

Tools can fall due to various reasons such as improper storage, lack of maintenance, human error, and environmental factors.

• Improper storage or handling of tools

• Lack of maintenance or inspection of tools

• Human error such as dropping or mishandling the tool

• Environmental factors such as vibrations or unstable surfaces

• Inadequate training or experience of the user