This study examined the effects of a minimum quantity lubrication (MQL) and a Cupric oxide‐ (CuO‐) based nanofluid on Inconel 718 machinability. Additionally, by using an MQL CuO‐based nanofluid during the turning process, Inconel 718’s tribological characteristics are optimised. The experimentation was done using the minimum quantity lubrication (MQL) method. With the aid of magnetic stirring and an ultrasonic bath process, CuO nanoparticles were dispersed in distilled water, sunflower oil, and soyabean oil to create nanofluid. Soyabean oil contains uniformly distributed CuO nanoparticles. All the experimental trials are designed based on the L₁₈ Taguchi‐based orthogonal arrays and performed on CNC turning under MQL and nanofluid environment. There are four input parameters that were selected at mixed level, namely, cutting speed, feed rate, weight % of CuO in the nanofluid, and flow rate to analyze surface roughness and tool wear. In addition to that, the response surface method was used to identify the optimum condition for better surface roughness and tool wear. Surface roughness and tool wear were measured using the surface roughness tester and toolmaker’s microscope, respectively. Experimental results observed that cutting speed and weight % highly affect surface roughness whereas cutting speed and flow rate affect tool wear. The predicted optimal values for lower surface roughness are 160 ml/hr flow rate, 92.99 m/min cutting speed, 3 weight % of CuO, and 0.1 mm/min feed rate and for low tool wear 80 ml/hr flow rate, 92.99 m/min cutting speed, 3 weight % of CuO, and 0.1 mm/min feed rate.

The biodegradability and comparatively less harmful degradation of polylectic acid (PLA) make it an appealing material in many applications. The composite material is used as a feed for a 3D printer, consisting of PLA as a matrix and graphene (3 wt.%) as reinforcement. The composite is extruded in the form of wires using a screw-type extruder machine. Thus, prepared wire is used to 3D print the specimens using fused deposition modeling (FDM) type additive manufacturing technology. The specimens are prepared by varying the different process parameters of the FDM machine. This study’s primary objective is to understand the tribological phenomena and surface roughness of PLA reinforced with graphene. Initially, pilot experiments are conducted to screen essential factors of the FDM machine and decide the levels that affect the response variables, such as surface roughness and wear. The three factors, viz., layer height, printing temperature, and printing speed, are considered. Further experiments and analysis are conducted using the Box–Beheken method to study the tribological behavior of 3D-printed composites and the effect of these parameters on surface roughness and wear loss. It is interesting to note that layer height is significant for surface roughness and wear loss. The optimum setting for minimum surface roughness is layer height at 0.16 mm, printing temperature at 180 °C, and printing speed at 60 mm/s. The optimum setting for minimum wear loss is layer height at 0.24 mm, printing temperature at 220 °C, and printing speed at 90 mm/s. The desirability function approach is used to optimize (multiobjective optimization) both surface roughness and wear loss. The layer height of 0.16 mm, printing temperature of 208 °C, and printing speed of 90 mm/s are the optimum levels for a lower surface roughness and wear loss. The SEM images reveal various wear mechanisms, viz., abrasive grooves, micro-fractures, and the presence of wear debris. The work carried out helps to make automobile door panels since they undergo wear due to excessive friction, aging, material degradation, and temperature fluctuations. These are taken care of by graphene addition in PLA with an optimized printing process, and a good surface finish helps with proper assembly.

New biomedical supportive and lightweight structures require the creation of sustainable polymer composites of high strength and wear resistance. This research explores the use of alkali-treated pineapple leaf fiber (PALF) reinforced epoxy composites and determines complete structure property wear relationships using combined mechanical, tribological, and microstructural analysis. The novelty of the work is based on the correlation of fiber content with the stiffness increment, the damage tolerance, and degradation behavior under friction conditions at controlled fabrication conditions. A hand lay-up method was used to manufacture composite laminates with 5-25 wt.% PALF. The tensile strength rose to 78 MPa and Youngs modulus rose to 3.5 GPa. Flexural strength increased to 112 MPa and flexural modulus to 3.7 GPa. The energy impact decreased by 12 and dropped to 20 kJ/m2 and Shore D hardness rose by 72 and 76, respectively, which means the increase in deformation and surface damage resistance. Tribological testing revealed that coefficient of friction and wear rate decreased to 0.51 and 3.7 x 10-6 mm 3/N-m respectively by fiber-supported load distribution and establishment of protective transfer films. The scanning electron microscopy showed that there was consistent fiber dispersion, good bonding of fiber matrix, and predominance of crack-bridging and pull-out processes involving the fracture resistance. The best mechanical tribological behavior was observed with a concentration of 10-15 wt.% PALF. A further study will involve biocompatibility studies, long-lasting stability, and surface functionalization to permit biomedical assistance elements like orthotic braces, prosthetic frames, and non-load-bearing auxiliary medical components.