Various laser powder bed fusion (LPBF) process parameters must be considered as they can independently affect the properties of end-product. However, many studies simply examine one or two LPBF process parameters. Laser power, scan speed, scan spacing, and layer height are the four primary LPBF process parameters that contribute to volumetric energy density (VED) used in LPBF. VED is often used as an optimization metric for LPBF process parameters, because it takes all four major parameters into consideration. Thus, this paper focuses on the effect of VED on the morphology and properties of part, and also discusses on the interrelationship between all four parameters. Common range used for each parameter is 70–400 W for laser power, 70–1800 mm/s for scan speed, 50–140 µm for scan spacing, and 20–50 µm for layer height. It can be seen as the VED increased, the microstructure of as-built titanium alloy Ti6Al4V components exhibited smaller α’ martensite size and larger columnar β grain. High VED can also reduce porosity and defect formation, which will help in increasing part density. The lowest surface roughness reported for LPBF Ti6Al4V is 4.91 µm. Meanwhile, the maximum microhardness obtained is 443 HV and the highest tensile strength achieved is 1400 MPa. The VED used for studies that obtained these results are in the range of 55–65 J/mm³. Thus, it can be concluded that the most suitable VED for LPBF printing of Ti6Al4V is around 55–65 J/mm³.

The use of kenaf fiber as a reinforcement material for polymer composites is gaining popularity, especially in the production of automotive components. The main objective of this current work is to relate the effect of alkali treatment on the single fiber itself and the composite material simultaneously. The effect of temperature condition during mechanical testing is also investigated. Composite materials with discontinuous natural kenaf fibers and epoxy resin were fabricated using a compression moulding process. The epoxy composites were reinforced with 50 wt% untreated and treated kenaf fibers. The kenaf fiber was treated with NaOH solution (6% by weight) for 24 h at room temperature. Kenaf fiber treated with NaOH treatment had a clean surface and no impurities. For the first time we can see that alkali treatment had a damaging effect on the mechanical properties of kenaf fibers itself and the treated kenaf/epoxy composites. The composite reinforced with untreated kenaf fiber and treated kenaf fiber showed increased tensile strength (72.85% and 12.97%, respectively) compared to the neat epoxy. Reinforcement of the composite with treated kenaf fiber decreased the tensile strength due to the fiber pull out and the formation of voids which weakens the adhesion between the fibers and matrix. The temperature conditions also play an important role in composites with a significant impact on the deterioration of composite materials. Treated kenaf fiber has thermal stability and is not sensitive to temperature and as a result reinforcement with treated kenaf gives a lower loss value of 76%.