Printing and Design (IT-803 (C)) - Important Questions

Describe in detail the following additive manufacturing techniques: Stereolithography (SLA), Laminated Object Manufacturing (LOM), Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), Selective Laser Melting (SLM), and Binder Jet technology. For each technique include: principle of operation, typical materials used, advantages, limitations, and typical application areas.

Compare Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS) with respect to: process principle, material compatibility, dimensional accuracy, surface finish, mechanical properties, build speed, and typical applications. Conclude which process you would select for a functional polymer prototype and why.

Discuss the key process parameters for additive manufacturing processes (examples: layer thickness $t$, build orientation, raster width, scan speed $v$, laser power $P$, hatch spacing $h$, binder saturation). Explain how each parameter affects part properties such as dimensional accuracy, surface finish, mechanical strength, and build time. Provide examples of trade-offs between speed and quality.

What are the important criteria for selecting an additive manufacturing process for a given application? Discuss how factors such as material compatibility, required mechanical properties, dimensional accuracy, surface finish, production volume, cost, and post-processing requirements influence the selection.

Discuss the application domains of additive manufacturing in detail. For each of the following domains give specific examples of parts/components made using AM and justify the choice of AM over conventional manufacturing: aerospace, electronics, healthcare (biomedical), defence, automotive, construction, food processing, and machine tools.

Explain the common post-processing operations required for additive manufactured parts. Discuss support removal, heat treatment, surface finishing (machining, polishing, chemical smoothing), infiltration or sintering (where applicable), and their effects on mechanical properties and dimensional accuracy.

Explain the Binder Jet additive manufacturing process. Discuss its working principle, suitable materials, advantages, limitations, and typical post-processing steps. Highlight industries and applications where Binder Jet is preferred.

Differentiate between Binder Jet and Selective Laser Melting (SLM) for producing metal parts. Compare in terms of process mechanics, part density, mechanical properties, required post-processing, and cost considerations.

Explain the role of scanning strategy in powder bed fusion processes (SLS/SLM). How do parameters such as laser power $P$, scan speed $v$, hatch spacing $h$, and scan pattern influence residual stresses, porosity, microstructure, and dimensional accuracy? Suggest methods to mitigate residual stresses.

Case study: You are required to manufacture a lightweight, load-bearing aerospace bracket with complex internal channels. Justify the selection of a suitable additive manufacturing process and propose a set of process parameters (including layer thickness $t$, build orientation, and any other key parameters). Discuss expected post-processing, testing, and quality assurance steps to ensure part reliability.