In relation to additive manufacturing, match the following:

Process		Layer creation technique		Material
P	Stereolithography	1	Injection of powder stream	I	Paper
Q	Fused deposition modeling	2	Extrusion of melted polymer	II	Epoxy
R	Laminated object manufacturing	3	Liquid layer curing	III	Titanium
S	Laser-engineered net shaping	4	Sheet material deposition	IV	ABS

The correct option is: P-3-II, Q-2-IV, R-4-I, S-1-III.

To understand why this match is correct, let us analyze each of the additive manufacturing processes step-by-step, linking them to their corresponding layer creation techniques and primary materials:

1. P: Stereolithography (SLA)
- Layer Creation Technique (3 - Liquid layer curing): Stereolithography uses a liquid photopolymer resin. A UV laser scans the surface of the resin to cure (solidify) it layer-by-layer.
- Material (II - Epoxy): Liquid photopolymer resins used in SLA are commonly epoxy-based or acrylate-based resins.
- Match: P-3-II

2. Q: Fused Deposition Modeling (FDM)
- Layer Creation Technique (2 - Extrusion of melted polymer): FDM works by melting a solid thermoplastic filament and extruding it through a heated nozzle, depositing it layer-by-layer.
- Material (IV - ABS): Acrylonitrile Butadiene Styrene (ABS) is one of the most widely used thermoplastic polymers in FDM.
- Match: Q-2-IV

3. R: Laminated Object Manufacturing (LOM)
- Layer Creation Technique (4 - Sheet material deposition): LOM involves stacking sheets of material (like paper, plastic, or metal), bonding them together with adhesive, and cutting the outer profile using a laser or knife layer-by-layer.
- Material (I - Paper): Paper sheets with adhesive backing are the classic and most common material used in LOM.
- Match: R-4-I

4. S: Laser-Engineered Net Shaping (LENS)
- Layer Creation Technique (1 - Injection of powder stream): LENS is a directed energy deposition technology. It injects a metal powder stream directly into a melt pool created by a high-power laser beam to deposit material.
- Material (III - Titanium): LENS is typically used for fabrication and repair of metal components, with titanium being a highly common material for these industrial applications.
- Match: S-1-III

Combining all of the above matches, we get: P-3-II, Q-2-IV, R-4-I, S-1-III.