Basics of Mechanical Engineering

Explore the fundamentals of engineering metrology, including measurement concepts and common terminologies. Learn how measurement drives quality management and discover the Greek roots of metrology.

Master the international system of units, detailing the seven base units—kilogram, second, ampere, mole, candela, meter, Kelvin—and the relative and absolute temperature scales.

Explore the four parts of metrology—scientific, industrial, legal, and fundamental—highlighting accuracy levels, traceability, standard development, and the role of the National Service of Legal Metrology.

Master key measurement terminologies in metallurgy, including accuracy, bias, calibration, drift, resolution, traceability, and precision, with practical examples comparing a micrometer and a universal length measuring machine.

Explore the concepts of nominal dimension, tolerance, and limits, and how limit systems and fit types—clearance, interference, and transmission—ensure interchangeability in mechanical parts.

Explore linear measuring instruments that determine the distance between surfaces, including vernier calipers, outside and digital micrometers, depth micrometers, and scales; understand millimeter units and how land graduations affect accuracy.

Perform comparative measurements using comparators to determine linear dimensional differences relative to a standard; dial indicators are common mechanical comparators, while electronic comparators offer higher accuracy and precision.

Explore how go/no-go gauges and plug gauges measure hole diameters against tolerance limits, using go and no-go sizes to judge whether a work piece passes or fails.

Lower the temperature of a body by extracting latent heat with a refrigerant through the evaporator, compressor, condenser, and expansion device. Recognize non-spontaneous nature of refrigeration and the cooling-refrigeration difference.

Power the vapor compression cycle by drawing refrigerant from the evaporator to maintain low temperature and pressure, and note compressor types and life affected by start-stops and condenser heat rejection.

Exchanges heat from the refrigerant vapor to an external medium, condenses the superheated vapor, classifies condensers by cooling medium and convection, and highlights coil cleaning for efficient heat transfer.

Use expansion devices to reduce condenser to evaporator pressure and regulate flow as load rises. Classify devices into fixed opening (capillary tube, orifice) and variable opening (manual, automatic, float type).

Explore refrigerants, fluids in evaporator tubes, and how selection hinges on thermodynamic and thermal-physical properties, environmental and safety properties, economics, including chlorine-free options like R 32 and ozone depletion concerns.

Examine multi pressure refrigeration systems using two or more compressors to reduce work input, noting oil transfer and refrigerants with high critical temperature and low freezing point.

Explore the complete vapor compression refrigeration system, including evaporator, compressor, condenser, and expansion device, and how heat is extracted from objects to enable cooling.

Understand moist air as a mixture of dry air and water vapor. Identify dry bulb temperature, relative humidity, humidity ratio, wet bulb temperature, and dew point.

Fans ventilate and cool spaces. Ceiling fans use blades on an impeller and a DC motor to direct airflow, with blade design affecting efficiency in axial, centrifugal, and cross-flow configurations.

Explore solar radiation as a primary natural energy source and renewable resource powering photosynthesis and applications; learn how wavelength ranges, reflection, and sun angles affect heating and daylight.

Explore refrigeration, dehumidification, and air conditioning across diverse applications, from hospitals that require 100% fresh air to malls and supermarkets using central systems with varied loads and temperature zones.

Explore the mechanical and physical properties of materials, including thermal conductivity, corrosion resistance, density, ductility, elasticity, hardness, plasticity, strength, fatigue, and toughness, and how processing and internal structure shape them.

Explore ferrous materials, iron-based alloys that offer strength and hardness, and learn how heat treatment and alloying elements modify their properties while addressing corrosion in cast iron and steel.

Non-ferrous materials do not contain iron and include copper, aluminium, tin, lead, zinc; copper offers corrosion resistance and conductivity, while aluminium is corrosion resistant and abundant in India.

Explore brass and bronze alloys, including alpha brass up to 36% zinc and alpha beta brass 36–46% zinc, tin bronze, gun metal, aluminium alloys with magnesium.

Classify production by scale and product, guiding plant managers to choose job lot, batch, or mass production and tailor machinery, tools, and processes for efficiency.

Differentiate production from productivity by examining how efficiently resources are used to achieve output. Use motorbikes and steelmaking examples to show higher productivity means fewer resources per unit and competitiveness.

Metal forming, a primary shaping process, uses mechanical forces on malleable metals to induce plastic deformation, boosting ultimate tensile strength, hardness, and yield point through strain hardening, while ductility declines.

Explore forging processes that shape metals with hammer blows, usually hot, and include hand, power, open die, and close die methods, plus die sinking for mass production.

Examine forging defects arising from raw material flaws and improper heating, including cracks, incomplete forging, misaligned dies, scale pits, and burnt metal, plus rapid plastic flow lines.

Discover how rolling plastically deforms metals between rolls, reducing cross-section and extending length under high compressive force; explore two-high, three-high, four-high, and cluster mills and their backup and working rolls.

Learn how die casting uses a two-part metal mold to shape molten metals, with gravity or pressure filling, cooling, extraction, and common alloys like zinc, aluminium, magnesium, and copper.