Manufacturing Practices (BT-106) - Important Questions

Define the term "pattern" used in foundry practice. Describe the various types of patterns and the purposes of pattern allowances (drawing, shrinkage, machining, distortion). Give typical values of allowances for common metals.

Explain the sand casting process in detail. Draw a flow diagram of the steps involved and discuss the causes and remedies for at least five common casting defects (e.g., blowholes, cold shuts, misruns, porosity, cracks).

Explain the purpose of a gating system in casting. Derive the expression for the theoretical pouring rate using energy considerations and state the assumptions. If the theoretical pouring velocity is $v=\sqrt{2gh}$, express the volumetric flow rate $Q$ through an orifice of area $A$ in terms of $A$, $g$ and $h$.

Compare die casting and permanent mould casting in terms of process features, advantages, limitations and typical applications. Give two examples of components produced by each method.

Describe the forging process. Differentiate between open-die and closed-die forging and explain the typical defects encountered in forging with their remedies.

Explain the principles of rolling. Discuss the factors affecting roll force and power. Define the terms "draft", "spread" and "roll bite" and explain how the maximum possible draft is related to the coefficient of friction and roll radius.

List and describe common defects in arc welding. For each defect give possible causes and remedies. Also state the role of heat input and welding parameters on weld quality.

Explain the working principles, equipment and typical applications of Gas Metal Arc Welding (GMAW/MIG) and Gas Tungsten Arc Welding (GTAW/TIG). Compare their advantages and limitations.

State and explain the Taylor tool life equation. Write the equation relating cutting speed $V$ and tool life $T$ using constants and show how the exponent is interpreted. If $V T^{n}=C$, explain the meaning of $n$ and $C$ and how the equation is used to select cutting speed.

Define cutting speed, feed and depth of cut. Explain their effect on material removal rate (MRR) and surface finish. Give the expression for MRR in turning in terms of workpiece diameter $D$, cutting speed $V$, feed $f$ and depth of cut $d$.

Describe the working principle, construction and use of a vernier caliper and a micrometer. Define least count and explain how to read measurements from these instruments. Discuss typical sources of error and precautions.

Explain the principle of Electrical Discharge Machining (EDM). Describe the process parameters that influence machining rate and surface integrity and list typical applications where EDM is preferred over conventional machining.