Engineering reference for Indian students

Manufacturing

Manufacturing Processes

5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.

Topics

Casting and Solidification
Solidification time follows Chvorinov's rule t = C(V/A)ⁿ (n ≈ 2), so a large volume-to-surface ratio freezes slowly. Risers are designed to freeze last and feed shrinkage, per PN Rao.
Welding and Joining
Arc-welding heat input is H = ηVI/v (J/mm), governing the heat-affected zone and cooling rate. Higher heat input gives a wider HAZ and slower cooling, per PN Rao.
Metal Forming
Plastic flow follows the power law σ = K·εⁿ, where n is the strain-hardening exponent and K the strength coefficient. Forming force depends on flow stress, area, and friction, per PN Rao.
$True strain \varepsilon = ln(\frac{L}{L_{0}}); true stress = \sigma_{nom}(1 + \varepsilon)$
Machining and Tool Wear
Tool life obeys Taylor's equation V·Tⁿ = C, so higher cutting speed sharply shortens tool life. Material removal, forces, and the Merchant circle analyse the cutting process, per PN Rao.
Powder Metallurgy
Powder metallurgy compacts metal powder to a green density (80–90 % of theoretical) then sinters it below the melting point to bond particles. Final properties depend on density and porosity, per PN Rao.