Basic Mechanical Engineering Concept

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Machine drawing is the language of the mechanical engineer.

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This section covers projection and line conventions, permanent joints (welded and riveted), temporary fasteners (bolts, nuts, screws, keys), and the tolerance, fit and surface-finish symbols that appear on every production drawing.

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Machine Drawing Basics Item What to know First-angle projection Object between observer and plane.

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Top view (plan) drawn BELOW front view; left-side view drawn on the RIGHT.

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Used by ISO/BIS (and Nepal).

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Third-angle projection Plane between observer and object.

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Top view ABOVE front view.

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Principal views Front view (elevation), top view (plan), side view (end view).

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Front view shows the most detail.

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Sectional view Imaginary cut shows interior; hatching lines thin at 45°.

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Ribs, shafts, bolts, keys, pins are NOT hatched when cut lengthwise.

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Dimensioning systems Aligned (read from bottom or right) and Unidirectional (all read from bottom).

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Line type Use Continuous thick Visible outlines and edges Continuous thin Dimension lines, extension lines, leader lines, hatching Dashed (thin) Hidden outlines and edges Chain thin (long dash-dot) Centre lines, axes, pitch circles Chain thin, thick at ends Cutting-plane lines Continuous thin freehand / zig-zag Break lines, limits of partial views Welded Joints • Basic joint types: butt, lap, T (tee), corner and edge joints. • Fillet weld (lap/T joints): throat t = 0.707 × leg size s (throat is the weakest section). • Strength of a transverse fillet weld:

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P = 0.707 · s · l · σt; parallel fillet weld (shear):

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P = 0.707 · s · l · τ (per weld). • Butt weld strength (tension):

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P = t · l · σt, where t = plate thickness. • Welding symbol: symbol below the reference line = weld on arrow side; above = other side.

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A flag = field weld; a circle at the junction = weld all around.

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Rivets and Riveted Joints • Rivet parts: head, shank, tail (point).

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Head types: snap/button (most common), pan, countersunk (flush surface), conical. • Joints: lap joint (plates overlap) and butt joint (single or double cover/strap).

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Arrangement: chain or zig-zag (staggered). • Unwin's formula for rivet diameter: d = 6√t (d, t in mm).

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Pitch p ≥ 2d (minimum). • Caulking and fullering make riveted joints leak-proof (boilers, tanks).

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Failure mode Strength (per pitch length) Tearing of plate between rivets Pt = (p − d) · t · σt Shearing of rivet (single shear) Ps = n · (π/4) d² · τ (double shear ≈ 1.875 × or 2 × single) Crushing of rivet/plate Pc = n · d · t · σc Solid plate strength P = p · t · σt Failure mode Strength (per pitch length) Joint efficiency η = least of (Pt, Ps, Pc) ÷ (p · t · σt) Bolt, Nut and Screw Fasteners • Bolt passes through clearance holes and is secured by a nut; stud has threads on both ends; tap bolt/cap screw screws into a tapped hole; set screw prevents relative motion (point bears on shaft). • Thread terms: pitch (crest to crest), lead = number of starts × pitch, major (nominal) diameter, minor (root) diameter.

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M10 × 1.5 = metric, 10 mm major diameter, 1.5 mm pitch. • Locking devices: lock (jam) nut, castle/slotted nut with split pin, spring washer, Simmonds (nylon-insert) nut, wire locking. • Hexagonal nut: across-flats ≈ 1.5d + 3 mm; nut height ≈ d (approx. drawing proportions).

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Thread form Angle / feature Typical use ISO metric (V) 60° General fasteners British Whitworth 55° Older British fasteners, pipes Square 0° (flanks ⊥ axis), highest efficiency Power screws: screw jack, presses Acme (trapezoidal) 29° (metric trapezoidal 30°) Lead screw of lathe, easier to cut than square Buttress 45°/7° (one flank ~ square) Heavy axial load in ONE direction: bench vice, gun breech Knuckle Rounded Rough use: railway couplings, bulb holders Keys, Keyways and Keyed Assembly Key Feature Sunk key (rectangular/square) Half in shaft, half in hub.

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Standard width w ≈ d/4; square key: t = w.

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Saddle key (flat/hollow) No keyway in shaft — transmits torque by FRICTION only; light duty.

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Woodruff key Semicircular; self-aligning; used on tapered shafts (machine tools, automobiles).

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Deep keyway weakens shaft.

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Feather key Fixed to one member; allows AXIAL SLIDING of hub (gear shifting).

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Gib-head key Taper key with head for easy removal.

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Splines Multiple keys integral with shaft; high torque with axial movement (gearbox, automobiles).

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Kennedy / tangent keys Pairs at 90°/120° for heavy torque and reversing loads. • A key is designed for shear (τ = 2T/(w·l·d)) and crushing (σc = 4T/(t·l·d)).

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A square key is equally strong in shear and crushing. • Effect of keyway on shaft strength:

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Moore's factor e = 1 − 0.2(w/d) − 1.1(h/d).

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Tolerance, Limits and Fits • Basic size: size from which limits are derived.

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Limits: upper and lower permissible sizes.

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Tolerance = Upper limit − Lower limit (always positive). • Deviation = limit − basic size.

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Fundamental deviation fixes position of tolerance zone (letters: capital for holes, small for shafts). • Allowance = intentional difference between maximum material limits of mating parts = (min. hole − max. shaft).

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Positive allowance → clearance. • Hole-basis system (preferred, H hole, lower deviation = 0) and Shaft-basis system (h shaft, upper deviation = 0).

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Hole basis is preferred because holes are harder to vary than shafts. • ISO 286 gives 20 IT grades (IT01, IT0, IT1–IT18).

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Standard tolerance unit: i = 0.45∛D + 0.001D (μm, D in mm).

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IT7 = 16i, IT8 = 25i, IT9 = 40i. • Taylor's principle for limit gauges:

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GO gauge checks the maximum-material condition (full form);

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NO-GO gauge checks one dimension at the least-material condition.

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Fit Condition Example Clearance Min. hole > max. shaft (always a gap) H7/g6 (sliding), H8/f7 (running), H11/c11 (loose) Transition May give clearance OR interference H7/k6, H7/n6 (location, keys, couplings) Interference Max. hole < min. shaft (always overlap) H7/p6 (press fit), H7/s6 (shrink fit, gears on shafts) Surface Finish • Surface texture = roughness (fine irregularities from the cutting process) + waviness + lay (direction of dominant pattern). • Ra (arithmetic mean / CLA value) is the most used parameter, measured in μm.

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Rz = mean peak-to-valley height;

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Rmax/Rt = maximum peak-to-valley. • Roughness grades:

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N1 = 0.025 μm to N12 = 50 μm (each grade roughly doubles). • Symbols: basic tick mark ✓ = any process; tick with horizontal bar = material removal REQUIRED; tick with circle = material removal NOT permitted. • Lay symbols: = parallel, ⊥ perpendicular, X crossed, M multidirectional, C circular, R radial. • Typical Ra: sand casting 12.5–25; turning/milling 0.8–6.3; grinding 0.1–1.6; honing 0.1–0.8; lapping/super-finishing 0.012–0.1 μm.

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Industrial Engineering Applications — Drawing, Tolerances and Standardisation • Interchangeability is the basis of mass production and assembly lines: parts made to specified limits and fits can be assembled without selective fitting or hand work.

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Selective assembly (sorting into groups) is used only when very close fits are needed cheaply. • Tolerance and cost: manufacturing cost rises steeply as tolerance is tightened (and as surface roughness is reduced) — the industrial engineer specifies the loosest tolerance that still works.

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Typical achievable roughness: turning ≈ 0.8–6.3 μm, grinding ≈ 0.2–1.6 μm, lapping ≈ 0.05–0.4 μm Ra. • Tolerance stack-up: in an assembly, the tolerances of individual parts add (worst-case) or combine statistically (RSS) — checked at the design stage to guarantee assembly and function; linked to process capability Cp = (USL − LSL)/6σ in quality control (Chapter 7). • GD&T;

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(geometric dimensioning and tolerancing — form, orientation, position, run-out with datums) makes inspection unambiguous; gauges (go/no-go plug and ring gauges, snap gauges) and CMMs are used on the shop floor. • Drawings used in industrial engineering: assembly and exploded views with item numbers feeding the bill of materials (BOM) for MRP; part drawings for process (route) sheets; layout drawings for plant and material-flow planning; welding and riveting symbols for fabrication estimates;

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CAD/CAM/PLM systems manage drawing revisions and engineering change orders. • Standardisation, simplification and variety reduction: fewer part types and standard fasteners reduce inventory, tooling and cost — a core industrial-engineering activity supported by national and international standards (NS, IS, ISO).

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This section covers the mechanical properties used to select materials, how they are tested, common metals and alloys, and the three main time- or environment-dependent failure modes: fatigue, creep and corrosion.

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Mechanical Properties Property Definition / key point Strength Ability to resist applied load without failure (yield strength, UTS).

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Elasticity Ability to regain original shape after load removal.

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Plasticity Ability to undergo permanent deformation without fracture.

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Ductility Ability to be drawn into WIRES (tensile).

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Measured by % elongation and % reduction in area.

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Mild steel ≈ 25% elongation.

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Malleability Ability to be hammered/rolled into SHEETS (compressive).

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Gold is the most malleable metal.

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Toughness Energy absorbed up to FRACTURE = total area under stress-strain curve.

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Measured by impact test.

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Resilience Energy absorbed within ELASTIC limit.

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Modulus of resilience = σy²/2E.

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Hardness Resistance to indentation, scratching, abrasion and wear.

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Brittleness Fracture with little or no plastic deformation (cast iron, glass).

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Opposite of ductility.

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Stiffness Resistance to elastic deformation; measured by Young's modulus E (steel ≈ 200 GPa).

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Material Testing • Tensile test (UTM): stress-strain curve points — proportional limit → elastic limit → upper & lower yield point (mild steel) → ultimate tensile strength (necking begins) → fracture. • Materials without a clear yield point (Al, high-carbon steel) use 0.2% offset proof stress. • Engineering stress falls after UTS due to necking; true stress keeps rising.

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Test Indenter / principle Remarks Brinell (BHN) 10 mm hardened steel ball, 3000 kgf (steel), 15–30 s BHN = load ÷ curved area of impression.

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Not for very hard/thin parts.

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Vickers (VHN) Square-base diamond pyramid, 136° apex All materials, thin sections;

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Rockwell Depth of penetration.

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1/16" ball, 100 kgf.

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120° diamond cone, 150 kgf Fast, direct reading;

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HRC for hardened steel.

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Shore scleroscope Rebound height of a diamond-tipped hammer Portable, large parts.

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Mohs scale Scratch test, 1 (talc) to 10 (diamond) Minerals.

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Izod impact Specimen as CANTILEVER, 10×10×75 mm, V-notch faces striker Measures toughness (J).

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Charpy impact Specimen SIMPLY SUPPORTED, 10×10×55 mm, striker hits side opposite notch Used for ductile-brittle transition.

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Metals and Alloys Alloy Composition Use / feature Brass Cu + Zn (70/30 cartridge;

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60/40 Muntz metal) Fittings, cartridges, radiator cores Bronze Cu + Sn (phosphor bronze adds P) Bearings, bushes, springs, statues Gun metal Cu 88 + Sn 10 + Zn 2 Valves, pump parts, bearings German silver Cu + Zn + Ni (no silver) Utensils, resistance wires Duralumin Al + ~4% Cu + Mg + Mn Aircraft structures — age hardenable Babbitt (white metal) Sn + Sb + Cu (or Pb base) Bearing linings Soft solder Pb + Sn Electrical joints Invar Fe + 36% Ni Very low thermal expansion: measuring tapes, clocks Monel Ni ~67% + Cu Corrosion resistant, marine, chemical Nichrome Ni + Cr Heating elements Stainless steel Fe + ≥ 10.5–12% Cr (+ Ni) Corrosion resistance by passive Cr2O3 film HSS (18-4-1) W 18 + Cr 4 + V 1 Cutting tools; red (hot) hardness • Effect of alloying elements in steel:

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Cr – hardness & corrosion resistance;

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Ni – toughness & strength;

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Mo – creep strength, reduces temper brittleness;

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V – grain refinement;

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Mn – hardenability, neutralises S (hot shortness);

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Si – deoxidiser, electrical steel;

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S – machinability (free-cutting) but hot shortness;

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Co – red hardness (super HSS).

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Fatigue of Metals • Fatigue is failure under repeated/fluctuating stresses at a stress well BELOW the ultimate (often below yield) strength. • S-N (Wöhler) curve: stress amplitude vs number of cycles.

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Ferrous metals show an endurance limit (~106–107 cycles; ≈ 0.5 σu for steel).

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Non-ferrous metals like Al have NO definite endurance limit. • Stress ratio R = σmin/σmax; completely reversed loading R = −1.

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Mean stress σm = (σmax + σmin)/2. • Fatigue fracture shows beach marks (progressive crack growth) and a rough final-fracture zone. • Reduced by: notches/stress raisers, poor surface finish, corrosion, tensile residual stress.

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Improved by: shot peening, nitriding, carburising, surface rolling (compressive residual stress), polishing. • Mean-stress design lines:

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Soderberg (yield, most conservative), Goodman (UTS, straight line), Gerber (parabola).

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Creep and Stress Fracture • Creep: slow, time-dependent permanent deformation under constant load, significant at T > ~0.4 Tm (absolute).

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Lead and plastics creep even at room temperature. • Creep curve stages:

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Primary (decreasing rate — strain hardening), Secondary (steady state, minimum constant rate — design basis), Tertiary (accelerating rate, necking, rupture). • Stress-rupture test: time to fracture at given stress and temperature.

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Larson-Miller parameter combines T and time. • Creep-resistant materials:

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Ni-based superalloys, Mo/Cr steels, ceramics — used in turbine blades, boiler tubes. • Ductile fracture: necking, cup-and-cone surface, dimples, slow crack growth, high energy.

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Brittle fracture: flat, shiny, cleavage/chevron marks, rapid, little energy. • Ductile-to-brittle transition occurs in BCC metals (steel) at low temperature;

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FCC metals (Al, Cu, Ni) do not show it (Titanic failure example).

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Corrosion and Its Control • Corrosion is electrochemical: the anode corrodes (oxidation), the cathode is protected.

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Rust ≈ hydrated Fe2O3. • Galvanic series (active → noble):

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Mg, Zn, Al, steel, cast iron, lead, tin, brass, copper, nickel, stainless (passive), silver, gold, platinum.

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Type Description Uniform Even attack over surface (rusting) Galvanic Two dissimilar metals in electrolyte; the more active (anodic) metal corrodes Pitting Localised deep pits (stainless steel in chlorides) — very dangerous Crevice In narrow gaps (under gaskets, washers) with stagnant electrolyte Intergranular Along grain boundaries; 'sensitisation' of stainless steel (Cr-carbide at 425–870 °C).

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Prevent with low C or Ti/Nb stabilisation Stress corrosion cracking Tensile stress + corrosive medium (season cracking of brass in ammonia) Erosion / fretting Fluid velocity or small vibratory motion removes protective film Selective leaching Dezincification of brass; graphitisation of cast iron • Control methods: proper material selection & design (avoid dissimilar contact, crevices); coatings (paint, galvanising = Zn coating, tinning, electroplating, anodising Al); cathodic protection — sacrificial anode (Mg, Zn) or impressed current; inhibitors; environment control (dehumidify, remove O2).

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Industrial Engineering Applications — Material Selection, Testing and Cost • Material selection balances strength, weight, corrosion resistance, machinability, availability and cost per unit of performance (e.g., Rs per unit of yield strength); value engineering/value analysis asks whether a cheaper material or a simpler design gives the same function (see Chapter 7/8). • Make-or-buy and standardisation of raw materials (standard sections, sheets, bar stock) reduce inventory and lead time;

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ABC/VED analysis is applied to raw-material stocks. • Testing in quality control: tensile, hardness and impact tests on incoming material (with acceptance sampling plans); non-destructive testing (NDT) — dye penetrant, magnetic particle, ultrasonic, radiographic and eddy current — used where parts must not be destroyed (welds, castings, pressure vessels). • Fatigue and creep data feed reliability engineering and preventive-maintenance intervals: most service failures of machine parts are fatigue failures, so endurance limit, stress concentration (notches, keyways, holes) and surface finish govern the life of shafts, springs and gears. • Corrosion adds cost through material loss, repair, downtime and protective coatings — painting, galvanising, cathodic protection and material substitution are compared on a life-cycle cost basis.

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Material science links atomic structure to properties.

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Key exam areas: crystal structures, how metals deform, solidification, phase diagrams and strengthening, the iron-carbon diagram, steels and cast irons, and polymers and composites.

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Crystal Structure • A unit cell is the smallest repeating unit of a crystal lattice.

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There are 7 crystal systems and 14 Bravais lattices. • Coordination number (CN) = number of nearest neighbours.

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APF (atomic packing factor) = volume of atoms ÷ volume of unit cell. • Allotropy (polymorphism) of iron: α-Fe (BCC) up to 912 °C → γ-Fe (FCC) 912–1394 °C → δ-Fe (BCC) 1394–1538 °C (melting).

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Structure Atoms / cell CN APF a vs r Examples Simple cubic 1 6 0.52 a = 2r Polonium BCC 2 8 0.68 a = 4r/√3 α-Fe, Cr, W, Mo, V, Na FCC 4 12 0.74 a = 2√2 r Al, Cu, Ni, Au, Ag, Pb, γ-Fe HCP 6 12 0.74 c/a = 1.633 Zn, Mg, Ti, Cd, Co Crystal Imperfections and Deformation • Point defects: vacancy, interstitial, substitutional;

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Schottky (cation-anion vacancy pair), Frenkel (vacancy + interstitial).

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Line defects: dislocations — edge (Burgers vector ⊥ dislocation line) and screw (Burgers vector ∥ line).

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Surface defects: grain boundaries, twin boundaries, stacking faults.

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Volume defects: voids, cracks, inclusions. • Plastic deformation occurs by slip (dislocation movement on close-packed planes and directions) and twinning (mirror-image shift, common in HCP and at low temperature). • Slip systems:

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FCC = 12 (very ductile);

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BCC = 48 but not close-packed (moderately ductile);

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HCP = 3 (low ductility at room temperature). • Strain (work) hardening: dislocation density rises with cold work → strength & hardness ↑, ductility ↓. • Cold working below recrystallisation temperature; hot working above it (≈ 0.4 Tm).

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Annealing of cold-worked metal: recovery → recrystallisation → grain growth.

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Solidification • Solidification = nucleation + growth.

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Homogeneous nucleation needs large undercooling; heterogeneous nucleation (on mould walls, inoculants) is easier and common. • Pure metals solidify at a constant temperature; alloys over a range.

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Crystals grow as tree-like dendrites. • Ingot/casting zones: chill zone (fine equiaxed at mould wall) → columnar zone → central equiaxed zone. • Faster cooling → more nuclei → finer grains → higher strength and toughness.

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Phase Relations and Phase Diagrams • Gibbs phase rule:

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F = C − P + 2 (F = degrees of freedom, C = components, P = phases).

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At constant pressure (metallurgy):

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At a eutectic point of a binary system F = 0 (invariant). • Lever rule gives the relative amounts of phases in a two-phase region. • Isomorphous system: complete solubility in liquid and solid (Cu-Ni).

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Pb-Sn solder (61.9% Sn, 183 °C).

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Invariant reaction On cooling Eutectic Liquid → Solid α + Solid β Invariant reaction On cooling Eutectoid Solid γ → Solid α + Solid β Peritectic Liquid + Solid α → Solid β Peritectoid Solid α + Solid β → Solid γ Monotectic Liquid L1 → Liquid L2 + Solid α Strengthening Mechanisms • Grain refinement — Hall-Petch: σy = σ0 + k·d−1/2 (smaller grains → stronger AND tougher). • Solid-solution strengthening — solute atoms distort lattice and hinder dislocations. • Strain hardening — cold work increases dislocation density. • Precipitation (age) hardening — solution treat → quench → age (Al-Cu duralumin).

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Over-ageing reduces strength. • Dispersion strengthening and martensitic transformation (quench hardening of steel).

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Iron-Carbon (Fe-Fe3C) Diagram Point / reaction Carbon % Temperature Result Peritectic 0.16–0.18% 1493–1495 °C L + δ → γ (austenite) Eutectic 4.3% 1147–1148 °C L → γ + Fe3C = LEDEBURITE Eutectoid 0.8% (0.76%) 727 °C (A1) γ → α + Fe3C = PEARLITE Max C in austenite 2.1% (2.14%) 1147 °C Divides steel and cast iron Max C in ferrite 0.022% 727 °C Ferrite is almost pure iron Cementite 6.67% — Hard, brittle iron carbide Fe3C Curie point (A2) — 768 °C Ferrite loses magnetism Phase / micro-constituent Nature Ferrite (α) BCC, soft, ductile, magnetic below 768 °C Austenite (γ) FCC, non-magnetic, stable above 727 °C in plain carbon steel Cementite (Fe3C) Hardest and most brittle constituent in the diagram Pearlite Lamellar mixture of ferrite + cementite (eutectoid) Ledeburite Eutectic mixture of austenite + cementite Martensite Supersaturated BCT formed by rapid quenching; hardest steel structure (not on equilibrium diagram) Bainite Ferrite + fine carbide formed by isothermal transformation (austempering) • Hypo-eutectoid steel (< 0.8% C) = ferrite + pearlite; eutectoid (0.8%) = 100% pearlite; hyper-eutectoid (0.8–2.1%) = pearlite + cementite. • Critical lines:

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A1 (727 °C, lower critical), A3 (upper critical, hypo-eutectoid), Acm (upper critical, hyper-eutectoid).

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Types of Steel and Cast Iron Steel Carbon % Uses Dead mild / low carbon < 0.15% / 0.15–0.3% Wires, sheets, structural sections, rivets, bolts Medium carbon 0.3–0.6% Shafts, axles, gears, rails, connecting rods High carbon 0.6–1.5% Springs, cutting tools, dies, drills, files Stainless (austenitic 18-8) 18% Cr, 8% Ni Non-magnetic, kitchen/chemical equipment Stainless (martensitic) 12–18% Cr, higher C Hardenable: cutlery, surgical tools Hadfield manganese steel 12–14% Mn, ~1.2% C Work hardens: rail crossings, crusher jaws Cast iron Carbon form Properties / uses Grey CI Graphite FLAKES (grey fracture) Good damping, machinability, compressive strength: machine beds, engine blocks White CI Cementite (white fracture), rapid cooling, low Si Very hard, brittle, wear parts; raw material for malleable CI Malleable CI Temper-carbon ROSETTES (annealed white CI) Some ductility: pipe fittings, brackets Ductile / Nodular / SG iron SPHEROIDAL graphite (Mg or Ce added) High strength & ductility: crankshafts, gears Chilled CI White surface, grey core Rolls, railway wheels Polymers and Composite Materials Polymer type Structure Examples Thermoplastics Linear/branched chains; soften on heating; recyclable PE, PP, PVC, PS, Nylon, PTFE (Teflon), PMMA (acrylic), PET Thermosets Cross-linked; permanently set; cannot be remelted Bakelite (phenol formaldehyde), epoxy, urea formaldehyde, polyester Elastomers Lightly cross-linked; large elastic strain Natural rubber, neoprene, silicone rubber • Polymerisation: addition (no by-product, e.g., polyethylene) and condensation (by-product such as water, e.g., nylon, Bakelite).

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Vulcanisation = cross-linking rubber with sulphur. • Glass transition temperature (Tg): below it polymer is rigid/glassy, above it rubbery. • Composite = matrix + reinforcement giving combined properties.

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By reinforcement: fibre (glass, carbon, aramid/Kevlar), particle (concrete, cermets), structural (laminates, sandwich panels). • Rule of mixtures (longitudinal, iso-strain):

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RCC, GFRP, CFRP, wood (natural composite).

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Industrial Engineering Applications — Process Metallurgy and Product Design • Heat treatment is a production process step with its own capacity, cost, cycle time and quality control (hardness testing, case-depth checks) — annealing before machining, hardening and tempering after; distortion in heat treatment affects downstream machining allowances. • Grain size and work hardening explain why cold-worked parts need inter-stage annealing in deep drawing and wire drawing — a sequencing decision in process planning. • Fe-C diagram knowledge guides material specification: low-carbon steel for welded structures and deep drawing, medium-carbon for shafts and gears, cast iron for machine beds (damping, cheap casting). • Polymers and composites allow light-weighting, part-count reduction (one moulding replacing several metal parts) and corrosion-free service; injection moulding gives very low unit cost at high volume but high tooling cost — a classic break-even comparison against machining (Chapter 10.2). • Failure analysis (fractography, metallography) finds the root cause of field failures and feeds corrective action in quality systems; recycling and material-flow considerations belong to environmental management (Chapter 9).

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Mechanical engineers routinely deal with motors, drives, transformers and control electronics.

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This section covers circuit fundamentals, AC circuits, electrical machines, and common electronic components and devices.

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Basic Quantities and Circuit Laws Quantity Unit & relation Charge (Q) Coulomb (C); electron charge = 1.6 × 10−19 C Current (I) Ampere (A) = C/s;

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I = Q/t Voltage (V) Volt (V) = J/C (work done per unit charge) Resistance (R) Ohm (Ω);

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R = ρL/A; rises with temperature for metals Power (P) Watt (W);

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P = VI = I²R = V²/R Energy (E) Joule;

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1 kWh (1 unit) = 3.6 × 106 J • Ohm's law:

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V = IR (at constant temperature). • KCL: algebraic sum of currents at a node = 0 (conservation of charge).

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KVL: algebraic sum of voltages around a closed loop = 0 (conservation of energy). • Series: same current;

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Req = R1 + R2 + …; voltage divides (V1 = V·R1/Req). • Parallel: same voltage;

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1/Req = 1/R1 + 1/R2 + …; two resistors:

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Req = R1R2/(R1+R2); current divides.

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Req < smallest resistor. • Equivalent circuits:

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Thevenin (Vth in series with Rth), Norton (IN in parallel with RN).

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Maximum power transfer when RL = Rth.

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AC Circuits • v = Vm sin ωt, ω = 2πf, T = 1/f.

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230 V single-phase, 400 V three-phase, 50 Hz. • RMS = 0.707 Vm; average (half cycle) = 0.637 Vm; form factor = 1.11; peak (crest) factor = 1.414. • Inductive reactance XL = 2πfL (current LAGS voltage by 90°); capacitive reactance XC = 1/(2πfC) (current LEADS by 90°). • Impedance Z = √(R² + (XL − XC)²).

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Series resonance at XL = XC: fr = 1/(2π√LC), Z minimum (= R), current maximum. • Power: active P = VI cos φ (W); reactive Q = VI sin φ (VAR); apparent S = VI (VA).

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Power factor = cos φ = P/S.

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Low pf is improved with capacitors. • Three-phase: star — VL = √3 Vph, IL = Iph; delta — VL = Vph, IL = √3 Iph.

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Motors and Generators • Generator works on Faraday's law of electromagnetic induction; direction by Fleming's RIGHT-hand rule.

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Motor works on force on a current-carrying conductor in a magnetic field; direction by Fleming's LEFT-hand rule. • DC generator EMF:

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A = P for lap winding, A = 2 for wave winding.

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The commutator converts internally generated AC into DC. • DC motor: back EMF Eb = V − IaRa; speed N ∝ Eb/φ; torque T ∝ φIa.

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DC motor Characteristic Application Shunt Nearly constant speed Lathes, fans, blowers, machine tools Series Very high starting torque; speed rises dangerously at no load — never start without load Traction, cranes, hoists, electric trains Compound Combination; high starting torque with limited no-load speed Presses, shears, rolling mills • Synchronous speed Ns = 120f/P (rpm).

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2-pole = 3000, 4-pole = 1500, 6-pole = 1000 rpm. • Alternator (synchronous generator): stationary armature, rotating field.

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Synchronous motor runs ONLY at Ns, is NOT self-starting, and when over-excited acts as a synchronous condenser for power-factor correction.

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Induction Machines • Three-phase stator winding produces a rotating magnetic field at Ns; rotor currents are induced (no electrical connection to rotor) — 'transformer action'. • Slip s = (Ns − N)/Ns; full-load slip typically 2–5%.

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Rotor frequency fr = s·f.

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Rotor can never reach synchronous speed (no induced EMF at s = 0). • Squirrel-cage rotor: rugged, cheap, low maintenance — most widely used industrial motor.

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Slip-ring (wound) rotor: external resistance gives high starting torque and speed control. • Starters:

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DOL (small motors), star-delta (starting current and torque reduced to 1/3), auto-transformer, rotor-resistance starter. • Single-phase induction motor is NOT self-starting — made to start by split-phase, capacitor-start, or shaded-pole methods (fans, pumps, washing machines).

33

Transformer • Static device working on mutual induction; transfers power at constant frequency; works on AC only (not DC). • EMF equation:

34

V1/V2 = N1/N2 = I2/I1 = K⁻¹ (turns ratio). • Losses: iron (core) loss = hysteresis + eddy current — constant, reduced by laminated silicon-steel core; copper loss = I²R — varies with load. • Maximum efficiency when copper loss = iron loss.

35

Efficiency is very high (95–99%) as there are no moving parts.

36

Rated in kVA. • Open-circuit test → iron loss; short-circuit test → full-load copper loss.

37

Types: core type, shell type; step-up, step-down; auto-transformer.

38

Electronic Components Component Key facts Resistor Colour code 0–9:

39

Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White.

40

Tolerance: gold ±5%, silver ±10%.

41

Capacitor C = Q/V (farad).

42

Blocks DC, passes AC.

43

Inductor Opposes change in current; energy = ½LI².

44

Passes DC, opposes AC.

45

Filters Low-pass, high-pass, band-pass, band-stop.

46

RC cut-off fc = 1/(2πRC).

47

Relay Electromagnetically operated switch — low-power circuit controls high-power circuit;

48

NO/NC contacts; also protective relays.

49

Integrated circuit Many components on one chip:

50

SSI < MSI < LSI < VLSI.

51

555 timer, 741 op-amp, 7805 regulator (+5 V).

52

Diodes, Transistors, Amplifiers and Oscillators • PN-junction diode: conducts in forward bias; cut-in voltage Si ≈ 0.7 V, Ge ≈ 0.3 V.

53

Main use: rectification (AC → DC). • Half-wave rectifier efficiency 40.6%, ripple factor 1.21; full-wave (centre-tap or bridge with 4 diodes) efficiency 81.2%, ripple factor 0.48. • Zener diode — operates in reverse breakdown for voltage regulation.

54

LED — emits light; photodiode — light sensor. • BJT (NPN/PNP; emitter, base, collector) is current-controlled.

55

IE = IB + IC; β = IC/IB; α = IC/IE; β = α/(1 − α).

56

Active region → amplifier; cut-off & saturation → switch. • Common-emitter (CE) amplifier: highest power gain, 180° phase shift — most widely used.

57

FET/MOSFET is voltage-controlled with very high input impedance. • Amplifier gain in dB = 20 log(Vo/Vi).

58

A (360°, least distortion, low efficiency), B (180°, ~78.5%), AB, C (< 180°, RF). • Op-amp: inverting gain = −Rf/Rin; non-inverting gain = 1 + Rf/Rin.

59

Ideal: infinite gain and input impedance, zero output impedance. • Oscillator converts DC into AC using positive feedback;

60

Barkhausen criterion: |Aβ| = 1 and loop phase = 0°/360°.

61

RC (phase-shift, Wien bridge) for audio;

62

LC (Hartley — tapped inductor, Colpitts — tapped capacitor) for RF; crystal for highest frequency stability.

63

Industrial Engineering Applications — Plant Electrical Systems and Energy Management • Electric motors (mostly three-phase induction motors) consume the largest share of industrial electricity; correct motor sizing matters because a lightly loaded motor runs at poor efficiency and poor power factor. • Power factor: industrial loads are inductive (motors, transformers, welding sets) → lagging p.f.

64

Capacitor banks are installed to improve power factor, which reduces line current (I = P/(√3·V·cos φ)), cable and transformer loading, losses and the p.f. penalty in the electricity bill. kVA = kW/cos φ. • Electricity tariff and energy audit: energy charge (Rs/kWh), demand charge (Rs/kVA of maximum demand), time-of-day tariff; load factor = average load ÷ maximum demand; energy conservation measures — variable-frequency drives (VFD) on pumps and fans (power ∝ speed³), high-efficiency (IE3/IE4) motors, LED lighting, compressed-air leak control, waste-heat recovery, avoiding idle running. • Automation and control: relays, contactors, PLCs, sensors, SCADA and drives make up the control system of modern plants; standby diesel generators and UPS give continuity in Nepal's load-shedding conditions. • Electrical safety: earthing, MCB/MCCB and fuses, RCCB, lock-out/tag-out (LOTO) before maintenance, insulation testing, statutory inspection.

1

Workshop practice questions test safety rules, hand tools and measuring instruments, the major machine tools (lathe, shaper, milling, grinding, drilling) and joining processes, especially arc and gas welding.

2

Safety Considerations • Wear PPE: safety goggles, safety shoes, apron/overalls, ear protection, welding helmet/shield with proper filter glass. • Do NOT wear gloves, loose clothing, rings or ties near rotating machines (lathe, drill, milling) — risk of entanglement.

3

Tie long hair. • Remove chips with a brush or hook, never with bare hands or compressed air towards the body.

4

Stop the machine before measuring or cleaning. • Keep guards in place; good housekeeping; know emergency stop and first aid.

5

Never leave a chuck key in the chuck. • Safety colours: red = stop/danger/fire equipment; yellow = caution; green = safe condition/first aid; blue = mandatory action.

6

Fire class (IS/EN) Burning material Extinguisher Class A Wood, paper, cloth Water, foam Class B Flammable liquids (oil, petrol, paint) Foam, CO2, dry chemical powder — NOT water jet Class C Flammable gases (LPG, acetylene) Dry chemical powder; isolate gas supply Class D Metals (Mg, Na, K) Special dry powder Electrical Live equipment CO2 or dry powder — NEVER water Hand Tools and Measuring Instruments Tool Key facts Files By cut: single, double, rasp.

7

By grade (coarse → fine): rough, bastard, second-cut, smooth, dead-smooth.

8

Shapes: flat, hand (one safe edge), square, round, half-round, triangular, needle.

9

Hacksaw Blade 250/300 mm; teeth point FORWARD; cuts on FORWARD stroke.

10

14 (soft/thick), 18 (general), 24 (tubes/angles), 32 (thin sheet).

11

Chisels Flat (general), cross-cut (keyways), half-round (oil grooves), diamond-point (square corners).

12

Hammers Ball-peen (most common in fitting), cross-peen, straight-peen, sledge, soft-face (mallet).

13

Punches Prick punch 30°–60° (light marks), centre punch 90° (drill locating).

14

Marking Scriber, surface plate, V-block, try square, angle plate, surface gauge, dividers, odd-leg caliper.

15

Vernier caliper Least count = 1 MSD − 1 VSD (typically 0.02 mm).

16

Measures outside, inside, depth.

17

Micrometer Least count = pitch ÷ thimble divisions = 0.5/50 = 0.01 mm.

18

Taps & dies Tap set: taper (1st), intermediate/plug (2nd), bottoming (3rd) — cut internal threads.

19

Dies cut external threads.

20

Tap drill ≈ major dia − pitch.

21

Reamer Finishes and sizes an already drilled hole (small allowance ~0.2 mm).

22

Lathe • Called the 'mother of machine tools'; work rotates, single-point tool feeds.

23

Size specified by swing over bed and distance between centres (length of bed). • Main parts: bed, headstock (spindle, speed gearbox), tailstock, carriage (saddle, cross-slide, compound rest, tool post, apron), feed rod, lead screw (used only for thread cutting), half nut. • Work holding:

24

3-jaw self-centring chuck (round/hexagonal work), 4-jaw independent chuck (irregular work), face plate, collets, centres with dog. • Operations: facing, plain/step turning, taper turning, threading, knurling (no metal removal — rolled pattern), parting/grooving, drilling, boring, chamfering. • Cutting speed V = πDN/1000 (m/min, D in mm).

25

Machining time T = L/(f·N) (L = length, f = feed mm/rev). • Taper turning methods: compound-rest swivel (short, steep tapers), tailstock set-over (long, slow tapers; offset = L(D − d)/2l), taper-turning attachment, form tool.

26

Shaper, Planer and Slotter • Shaper: tool reciprocates, work is fed; produces flat horizontal, vertical, inclined surfaces, slots and keyways.

27

Size = maximum stroke length. • Uses a quick-return mechanism (crank and slotted lever / Whitworth / hydraulic): return stroke faster than cutting stroke; typical ratio ≈ 3:2. • Planer:

28

WORK reciprocates under a stationary tool — used for large, heavy jobs.

29

Slotter: vertical shaper for internal keyways and slots.

30

Milling Machine • Multi-point rotating cutter; work fed against it.

31

Types: column-and-knee (horizontal, vertical, universal), bed type, planer type. • Up (conventional) milling: cutter rotates AGAINST feed; chip thickness zero → max; tends to lift work; used on most machines. • Down (climb) milling: cutter rotates WITH feed; chip max → zero; better surface finish and tool life; needs backlash eliminator. • Dividing (indexing) head with 40:1 worm ratio.

32

Simple indexing: crank turns = 40/N (N = number of divisions).

33

E.g., 20-tooth gear → 2 turns. • Cutters: plain/slab, side-and-face, end mill, T-slot, form (gear) cutter, fly cutter, slitting saw.

34

Grinding Machine • Abrasive machining for fine finish and accuracy; also for hard materials.

35

Types: surface, cylindrical, internal, centreless, tool-and-cutter. • Abrasives:

36

Aluminium oxide (A) — high-tensile materials (steel);

37

Silicon carbide (C) — low-tensile/brittle materials (cast iron, brass, carbides);

38

Diamond and CBN — superabrasives. • Wheel marking example A 46 K 5 V 17 = abrasive (A) – grain size (46, medium) – grade/hardness (K;

39

A = soft → Z = hard) – structure (5; dense → open) – bond (V = vitrified) – maker's code. • Bonds:

40

V vitrified (most common), S silicate, B resinoid, R rubber, E shellac, M metal. • Rule: hard material → soft wheel; soft material → hard wheel. • Dressing removes glazing/loading to restore sharpness; truing restores wheel shape and concentricity.

41

Glazing = dull grains; loading = chips clog pores.

42

Drills and Drilling Processes • Machines: portable, sensitive (bench) — light work, hand feed; upright/pillar; radial — large heavy work, arm swings; gang; multi-spindle. • Twist drill: point angle 118° (general), helix angle ≈ 30°, lip clearance 8–12°.

43

Made from HSS; parts: shank, body, point, flutes, web, margin. • Operations: drilling, reaming (finishing), boring (enlarging), counterboring (flat-bottom recess for bolt head), countersinking (conical recess for flat screw head), spot facing (flat seat), tapping.

44

Joining and Fabrication • Permanent joints: welding, brazing, soldering, riveting, adhesive bonding.

45

Temporary joints: bolts, screws, keys, pins. • Soldering: filler melts below 450 °C; brazing: filler above 450 °C but below base-metal melting point (base metal NOT melted); welding: base metal fuses. • Sheet-metal operations: shearing, bending, blanking (punched piece is product), punching/piercing (punched piece is scrap), notching, drawing.

46

Arc Welding • Heat from an electric arc between electrode and work; arc temperature ≈ 5000–6000 °C.

47

Open-circuit voltage ≈ 50–90 V; arc voltage ≈ 20–40 V. • In DC welding about 2/3 of heat is at the positive terminal.

48

DCSP/DCEN (electrode −ve, work +ve): deeper penetration, thick plates.

49

DCRP/DCEP (electrode +ve): shallow penetration, thin sheets, faster electrode melting. • Electrode flux coating: shields arc, stabilises arc, forms protective slag, deoxidises and adds alloying elements. • Processes:

50

SMAW (stick), GMAW/MIG (consumable wire + inert/active gas), GTAW/TIG (non-consumable tungsten electrode, argon — Al, stainless, thin work), SAW (submerged arc, granular flux, thick plates, automatic), plasma arc. • Defects: porosity, slag inclusion, undercut, lack of fusion/penetration, cracks, spatter, distortion.

51

Gas Welding (Oxy-Acetylene) Flame O2 :

52

C2H2 Use Neutral ≈ 1 :

53

1 Most common: mild steel, cast iron, Cu, Al; ≈ 3200 °C at inner cone tip Carburising (reducing) Excess acetylene High-carbon steel, hard-facing (Stellite), Monel Oxidising Excess oxygen Brass and bronze (hottest flame ≈ 3480 °C) • Acetylene is stored dissolved in acetone in a porous filler; free acetylene is unsafe above ~1 bar (15 psi).

54

Cylinder colours: oxygen black, acetylene maroon. • Leftward (forehand) technique for thin plates (< 5 mm); rightward (backhand) for thick plates. • Oxy-fuel cutting works by rapid oxidation of ferrous metals; not suitable for stainless steel, cast iron or aluminium without special methods.

55

Industrial Engineering Applications — Machine Shop as a Production System • Machining time estimation (used for standard times, costing and capacity planning): cutting speed V = πDN/1000 m/min; machining time t = L/(f·N) minutes for turning and drilling (L = length of cut including approach and over-travel, f = feed mm/rev, N = rpm); for milling t = (L + approach)/(fz·z·N). • Tool life:

56

Taylor's equation VTn = C (n ≈ 0.1–0.15 HSS, 0.2–0.4 carbide, 0.4–0.6 ceramic) — used to find the economical cutting speed that minimises cost or maximises production rate; tool-change time and tool cost enter the calculation. • Capacity and utilisation: machine-hour capacity per shift, utilisation = running time ÷ available time, OEE = availability × performance × quality (Chapter 8); set-up (changeover) time reduction (SMED) is a key lean technique because it allows smaller batches. • Jigs and fixtures locate and hold the work (3-2-1 location principle) — they remove marking-out and skilled setting, cut cycle time, and give repeatable quality; poka-yoke (mistake-proofing) features prevent wrong loading. • Process planning: selecting operations, machines, tools, speeds/feeds and sequence on a route sheet; group technology / cellular layout groups similar parts into families processed in a machine cell (Chapter 6). • Workshop safety and housekeeping: machine guarding, PPE, LOTO, material-handling rules, 5S (sort, set in order, shine, standardise, sustain), safe welding practice (ventilation, screens, fume extraction), accident reporting and the safety statistics of Chapter 9.

1

Management questions are largely theory- and name-based: organisation types, management thinkers and theories, leadership and communication, entrepreneurship, motivation theories, HRM functions, business plans, MIS and technology management.

2

Organization and Its Types • An organization is a structured group of people working together towards common goals.

3

Formal organisation is deliberately designed (charts, rules); informal arises from social relations (grapevine). • Key concepts: authority, responsibility, accountability, delegation, span of control (number of subordinates per manager), unity of command (one boss), scalar chain (line of authority), centralisation vs decentralisation. • Forms of business ownership: sole proprietorship, partnership, joint-stock company (private/public limited), cooperative, public enterprise (state-owned).

4

Structure Features Merit / demerit Line (military/scalar) Direct vertical authority Simple, quick decisions, unity of command / overloads executives, no specialists Line & staff Line managers + advisory staff specialists Expert advice / line-staff conflict Functional (F.W.

5

Taylor) Work divided by specialist function;

6

8 functional foremen Specialisation / violates unity of command Divisional Divisions by product, region or customer Accountability / duplication of resources Matrix Functional + project;

7

DUAL authority (two bosses) Flexible for projects / conflict, confusion Project Temporary team for a project Focus / disbands after project Committee Group decision-making Pooled judgement / slow, diluted responsibility Management Functions and Modern Management Theory • Fayol's functions:

8

Planning, Organising, Commanding, Coordinating, Controlling.

9

Planning, Organising, Staffing, Directing, Coordinating, Reporting, Budgeting.

10

Planning is the primary function. • Levels: top (strategic), middle (tactical), lower/supervisory (operational).

11

Katz's skills: technical (most at lower level), human (all levels), conceptual (most at top level). • Fayol's 14 principles: division of work, authority & responsibility, discipline, unity of command, unity of direction, subordination of individual interest, remuneration, centralisation, scalar chain, order, equity, stability of tenure, initiative, esprit de corps.

12

School / theory Proponent Core idea Scientific management F.

13

Taylor (father of scientific management) Time & motion study, standardisation, differential piece-rate, functional foremanship Motion study Frank & Lillian Gilbreth Therbligs (17 basic motions) Gantt chart Henry Gantt Bar chart for scheduling; task-and-bonus plan Administrative management Henri Fayol (father of modern management) 14 principles; functions of management Bureaucracy Max Weber Hierarchy, rules, impersonality, merit Human relations Elton Mayo — Hawthorne experiments Social and psychological factors affect productivity School / theory Proponent Core idea Systems approach Bertalanffy, Katz & Kahn Organisation as open system: input → process → output with feedback Contingency / situational Fiedler, Lawrence & Lorsch No one best way — 'it depends' on situation MBO Peter Drucker Management by Objectives: jointly set, measurable goals TQM Deming, Juran, Crosby Continuous improvement (PDCA), customer focus Theory Z William Ouchi Japanese-style: lifetime employment, collective decisions Leadership and Communication • Leadership styles: autocratic (leader decides), democratic/participative, laissez-faire (free rein), paternalistic; transformational (inspires change) vs transactional (reward/punishment exchange). • Theories: trait theory; behavioural (Ohio State — initiating structure & consideration;

14

Managerial Grid (Blake & Mouton:

15

9,1 authority-compliance;

16

5,5 middle-of-the-road;

17

9,9 team management — ideal);

18

Fiedler's contingency (LPC scale);

19

Hersey-Blanchard situational (telling, selling, participating, delegating);

20

House's path-goal. • Communication process: sender → encoding → message/channel → decoding → receiver → feedback; noise disturbs any stage. • Formal channels: downward (orders), upward (reports, suggestions), horizontal/lateral (peers), diagonal.

21

Informal channel: grapevine (fast, may distort). • Barriers: semantic (language), psychological (emotions, perception), organisational (hierarchy), physical (noise, distance).

22

The 7 Cs: clear, concise, concrete, correct, coherent, complete, courteous.

23

Entrepreneurship • Entrepreneur: a person who identifies opportunities, innovates, organises resources and bears risk.

24

Joseph Schumpeter — entrepreneur as innovator, 'creative destruction'. • Types (Danhof): innovative, imitative (adoptive), Fabian (cautious, sceptical), drone (refuses change).

25

Intrapreneur = entrepreneur within an existing organisation. • Traits: need for achievement (McClelland), risk-taking, creativity, vision, self-confidence, persistence. • Finance sources: own equity, bank loans, angel investors (early-stage individuals), venture capital (high-growth firms for equity), crowdfunding, government schemes.

26

Motivation Theory Proponent Key idea Need hierarchy Abraham Maslow Physiological → Safety → Social → Esteem → Self-actualisation (highest) Two-factor Frederick Herzberg Hygiene factors (salary, policy, working conditions, security) prevent dissatisfaction;

27

Motivators (achievement, recognition, work itself, responsibility, growth) motivate Theory X / Theory Y Douglas McGregor X: people dislike work, need control;

28

Y: people are self-motivated and seek responsibility Need theory David McClelland Needs for achievement, affiliation and power ERG theory Clayton Alderfer Existence, Relatedness, Growth Expectancy theory Victor Vroom Motivation = Expectancy × Instrumentality × Valence Equity theory J.

29

Stacy Adams People compare input/output ratio with others Goal-setting Edwin Locke Specific, challenging goals raise performance Reinforcement B.

30

Skinner Behaviour shaped by consequences Human Resource Management (HRM) • Functions:

31

HR planning → job analysis (job description = duties of the job; job specification = qualities required of the person) → recruitment → selection → placement → induction/orientation → training & development → performance appraisal → compensation → employee relations, safety & welfare → separation. • Recruitment is a positive process (attracts many applicants); selection is a negative process (rejects unsuitable ones).

32

Sources: internal (promotion, transfer) and external (advertisement, campus, agencies). • Training = short-term, job-specific skills for operatives; development = long-term growth for managers.

33

On-the-job: apprenticeship, job rotation, coaching; off-the-job: lectures, case study, simulation, vestibule training (replica of workplace). • Appraisal methods: rating scales, ranking, paired comparison, critical incident, MBO, 360° feedback (superiors, peers, subordinates, customers).

34

Development of Business Plan • A business plan is a written document describing the business idea, market, operations and finances — used to guide the venture and attract investors/lenders. • Typical contents: executive summary (written last, placed first), company description, market analysis, organisation & management, products/services, marketing & sales strategy, operations plan, financial plan (projected income statement, cash flow, balance sheet, break-even), funding request, appendix. • Feasibility study: technical, market, financial, economic, legal and environmental feasibility. • SWOT:

35

Strengths & Weaknesses (internal), Opportunities & Threats (external).

36

Political, Economic, Social, Technological, Legal, Environmental. • Break-even point (units) = Fixed cost ÷ (Selling price − Variable cost per unit).

37

Contribution = SP − VC.

38

Other tools: payback period, NPV, IRR, B/C ratio.

39

Management Information System (MIS) • MIS is an integrated system of people, hardware, software, data and procedures that provides timely, accurate and relevant information for managerial decision-making. • Data = raw facts; information = processed, meaningful data.

40

Good information is accurate, timely, relevant, complete and concise.

41

System Level / purpose TPS (Transaction Processing System) Operational level — records routine transactions (payroll, billing) MIS Middle management — periodic structured reports for control DSS (Decision Support System) Semi-structured/unstructured decisions; 'what-if' analysis EIS / ESS (Executive) Top management — strategic, summarised dashboards ERP Integrates all departments (finance, HR, production, sales) on a common database Expert system Uses knowledge base and inference engine to mimic an expert Technology Management • Technology management = planning, developing, acquiring and using technology to achieve strategic objectives.

42

Includes R&D;, technology selection, transfer, absorption and assessment. • Technology transfer: vertical (research → commercial product) and horizontal (from one organisation/country to another).

43

Modes: licensing, joint venture, FDI, turnkey projects, purchase of equipment. • Technology life cycle (S-curve): emergence → growth → maturity → decline.

44

Incremental vs radical/disruptive innovation (Clayton Christensen). • Diffusion of innovation (E.

45

Rogers): innovators 2.5%, early adopters 13.5%, early majority 34%, late majority 34%, laggards 16%. • Technology forecasting:

46

Delphi method (anonymous expert rounds), trend extrapolation, scenario analysis.

47

IPR: patent (~20 years), copyright, trademark, industrial design, trade secret.

48

Make-or-buy decisions.

49

Industrial Engineering Applications — Management in Practice • Section 1.6 is the management foundation of the whole Industrial Engineering syllabus: organisation structures and spans of control reappear in production organisation (Chapter 5), motivation and HRM in work design and ergonomics (Chapter 6), MIS in ERP and information systems (Chapters 8 and 10.4), and entrepreneurship and business plans in project appraisal (Chapter 10.2). • Scientific management (F.

50

Taylor) — time study, standardisation of methods and tools, scientific selection and training, differential piece-rate, functional foremanship;

51

Frank and Lillian Gilbreth — motion study and therbligs;

52

Henry Gantt — Gantt chart and task-and-bonus plan;

53

Henri Fayol — 14 principles and the functions of management (planning, organising, commanding/staffing, coordinating, controlling);

54

Max Weber — bureaucracy;

55

Elton Mayo — Hawthorne studies and the human-relations school; operations research/systems approach — modern quantitative management. • Organisation types: line, line-and-staff, functional, project, matrix (dual reporting — common in engineering projects), divisional; formal vs informal; span of control (wide → flat organisation, fewer levels; narrow → tall organisation). • Motivation:

56

Maslow's hierarchy (physiological → safety → social → esteem → self-actualisation), Herzberg's two-factor theory (hygiene factors prevent dissatisfaction; motivators — achievement, recognition, responsibility, growth — create satisfaction), McGregor's Theory X and Y, Vroom's expectancy theory, McClelland's needs theory; financial and non-financial incentives, wage-incentive plans (Halsey, Rowan, Taylor differential piece-rate — Chapter 6). • Leadership and communication: autocratic, democratic/participative, laissez-faire styles; managerial grid; formal and informal communication channels and barriers. • HRM: manpower planning, recruitment and selection, training and development, performance appraisal, job evaluation and merit rating, wage and salary administration, industrial relations, trade unions and the Labour Act; industrial safety and welfare. • Entrepreneurship and business plan: identifying an opportunity, market survey, technical feasibility, financial plan (capital requirement, break-even, cash flow, NPV/IRR — Chapter 10.2), organisation and management plan, risk analysis; in Nepal, registration with the Office of Company Registrar or the Department of Industry/Cottage and Small Industries Office, PAN/VAT registration, environmental clearance (IEE/EIA) and industry classification under the Industrial Enterprises Act. • MIS and technology management: transaction processing → MIS → decision support and ERP; technology forecasting, selection, transfer, absorption and R&D management; automation and Industry 4.0 (IoT, data analytics).