Additive manufacturing using fused deposition modelling (FDM) is an affordable and efficient way to produce functional parts and prototypes. However, the FDM-manufactured parts, particularly those made of polylactic acid (PLA), has some drawbacks regarding accuracy and surface finish. To address this, post-processing techniques such as ironing can be applied. However, little is known about the effect of ironing process parameters on surface roughness, and there is a lack of comparative studies on contact and non-contact measurement methods. This study aims to address these gaps by investigating the impact of path speed, ironing spacing, and flow rate on the surface roughness of FDM-produced PLA samples using both contact and non-contact measurement methods. The results show that the ironing process can lead to a significant reduction in surface roughness values, and careful optimization of process parameters can further minimize roughness. The study highlights the advantages and limitations of contact and non-contact methods for surface roughness analysis and provides guidance on selecting the appropriate method for a given application and material.

This study focuses on polyamide 6/organo-modified montmorillonite (PA6/OMMT) nanocomposites as potential liner materials, given the growing interest in enhancing the performance of type IV composite overwrapped hydrogen storage pressure vessels. The mechanical properties of PA6/OMMT composites with varying filler concentrations were investigated across a temperature range relevant to hydrogen storage conditions (−40 °C to +85 °C). Liner collapse, a critical issue caused by rapid gas discharge, was analyzed using an Ishikawa diagram to identify external and internal factors. Mechanical testing revealed that higher OMMT content generally increased stiffness, especially at elevated temperatures. The Young’s modulus and first yield strength exhibited non-linear temperature dependencies, with 1 wt. per cent OMMT content enhancing yield strength at all tested temperatures. Dynamic mechanical analysis (DMA) indicated that OMMT improves the storage modulus, suggesting effective filler dispersion, but it also reduces the toughness and heat resistance, as evidenced by lower glass transition temperatures. This study underscores the importance of optimizing OMMT content to balance mechanical performance and thermal stability for the practical application of PA6/OMMT nanocomposites in hydrogen storage pressure vessels.

The 1.4306 austenite stainless steel has been prominently utilized as a material in the automotive and aerospace industry. Considerable interest has been garnered in the machinability of stainless steel owing to its high strength and poor thermal conductivity. The aim of this study is to ascertain the influential cutting parameters, specifically the cutting speed and feed rate, on cut-ting forces, cutting temperature, and chip evaluation. Thus, austenite stainless steel was subjected to free-cutting using a carbide recessing tool under dry conditions. The principle of measuring cutting temperature, a complex procedure due to varying thermal homogeneity, was elucidated. For the turning experiments in question, the standard Taguchi orthogonal array L9 (3²), featuring two factors and three levels, was employed. The experimental results were analyzed using MiniTab 17 software. The findings reveal a substantial effect of feed rate on cutting force, cutting temperature, and chip evaluation. The highest cutting force and cutting temperature were observed at a feed rate of 0.15 mm/rev. Conversely, the cutting force was minimized at a cutting speed of 100 m/min, indicating potential for increasing the cutting speed. The augmentation of feed rate led to chip compression and discoloration, attributed to elevated cutting force and a larger chip cross-section that efficiently dissipates heat from the cutting zone.

The 1.4306 austenite stainless steel has been prominently utilized as a material in the automotive and aerospace industry. Considerable interest has been garnered in the machinability of stainless steel owing to its high strength and poor thermal conductivity. The aim of this study is to ascertain the influential cutting parameters, specifically the cutting speed and feed rate, on cut-ting forces, cutting temperature, and chip evaluation. Thus, austenite stainless steel was subjected to free-cutting using a carbide recessing tool under dry conditions. The principle of measuring cutting temperature, a complex procedure due to varying thermal homogeneity, was elucidated. For the turning experiments in question, the standard Taguchi orthogonal array L9 (3²), featuring two factors and three levels, was employed. The experimental results were analyzed using MiniTab 17 software. The findings reveal a substantial effect of feed rate on cutting force, cutting temperature, and chip evaluation. The highest cutting force and cutting temperature were observed at a feed rate of 0.15 mm/rev. Conversely, the cutting force was minimized at a cutting speed of 100 m/min, indicating potential for increasing the cutting speed. The augmentation of feed rate led to chip compression and discoloration, attributed to elevated cutting force and a larger chip cross-section that efficiently dissipates heat from the cutting zone.