The surface finish is an important characteristic in the incremental sheet forming (ISF) process and is often influenced by numerous factors within the forming process. Therefore, this research was aimed at identifying the optimal forming parameters through the Taguchi method to produce high-quality formed products. The forming tool radius, spindle speed, vertical step increment, and feed rate were chosen as forming parameters in the experimental design, with surface roughness as the response variable. Taguchi L16 orthogonal array design and analysis of variance (ANOVA) test were used to identify the parameter’s optimal settings and examine the statistically significant parameters on the response, respectively. Results confirmed that a significant reduction in surface roughness occurred with a drop in vertical step size and an increase in feed rate. In detail, the vertical step size has the most significant influence on the surface roughness, followed by the feed rate and the forming tool radius. In conclusion, the optimum level settings were obtained: forming tool radius at level 3, spindle speed at level 1, vertical step size at level 1, and feed rate at level 4. Additionally, confirmation experiment results based on the optimal settings indicated a good agreement against the experimental observation. Further, the response surface methodology (RSM) was also exploited to devise a mathematical model for predicting the surface roughness. The results comparison confirmed that both techniques could effectively improvise the surface finish.

Incremental sheet metal forming can manufacture various sheet metal products without a dedicated punch and die set. In this study, we developed a two-stage incremental forming process to decrease shape errors in the conventional incremental forming process. The forming process was classified into the first single point incremental forming (1st SPIF) process for forming a product and the counter single point incremental forming (counter SPIF) process to decrease shape error. The counter SPIF gives bending deformation in the opposite direction. Furthermore, the counter SPIF compensates for shape errors, such as section deflection, skirt spring-back, final forming height, and round. The tool path of the counter SPIF has been optimized through a relatively simple optimization method by modifying the tool path of the previous step. The tool path of the 1st SPIF depends on the geometry of the product. An experiment was performed to form a circular cup shape to verify the proposed tool path of the 1st and counter SPIF. The result confirmed that the shape error decreased when compared to the conventional SPIF. For the application, the ship-hull geometry was adopted. Experimental results demonstrated the feasibility of the two-stage incremental forming process.

Molten carbonate fuel cells (MCFCs) use molten carbonate as an electrolyte. MCFCs operate at high temperatures and have the advantage of using methane as a fuel because they can use nickel-based catalysts. We analyzed the performance of an internal manifold-type MCFC, according to operating conditions, using computational fluid dynamics. Different conditions were used for the external and internal reforming-type MCFCs. Flow directions, gas utilization, and operating temperatures were used as the conditions for the external reforming-type MCFCs. The S/C ratio and reforming area were used as the conditions for internal reforming-type MCFCs. A simulation model was developed, considering gas transfer, reforming reaction, and heat transfer. The simulation results of external reforming-type MCFCs showed similar pressure drops in all flow directions. As the gas utilization decreased, the temperature decreased, but the performance increased. The performance improved with increasing operating temperatures. The simulation results for the internal reforming-type MCFCs showed that more hydrogen was produced as the S/C ratio decreased, and the performance increased accordingly. More hydrogen was produced as the reforming area increased. However, similar performance was obtained when the reforming area contained the same active area. The external and internal reforming-type MCFCs were compared under the same conditions. The efficiency of the external reforming-type MCFCs is higher than that of the internal reforming-type MCFCs.

This study proposes a novel system integrating a molten carbonate fuel cell (MCFC) with a dry reforming process (DR-MCFC) and develops a corresponding simulation model. In a DR-MCFC, the reacting gases from the dry reforming of methane (DRM) process are fed into a molten carbonate fuel cell. CH₄ and CO₂ were used as the reaction gases, while N₂ was employed as the carrier gas and introduced into the DRM. Following the DRM, the reformed gases were humidified and injected into the anode of the MCFC. A simulation model combining the dry reforming process and the MCFC was developed using COMSOL Multiphysics to evaluate the system’s performance and feasibility. The mole fraction of H₂ after the DRM ranged from 0.181 to 0.214 under five different gas conditions. The average current density of the fuel cell varied between 1321.5 and 1444.9 A·m⁻² at a cell voltage of 0.8 V, which was up to 27.07% lower than that of a conventional MCFC operating at 923 K due to the lower hydrogen concentration in the anode. Based on these results, the integration of dry reforming with the MCFC’s operation did not cause any operational issues, demonstrating the feasibility of the proposed DR-MCFC system.