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.

Nickel-based superalloys are among the most difficult materials to machine because they have high thermal strength, they are prone to hardening, carbides severely abrade the tool, and they have very poor thermal conductivity. Slot milling is a specific issue as it is characterized by rapid tool wear and frequent tool breakages. This is why reconditioned tools are frequently employed in industrial environments, as they can considerably decrease the expenses associated with tools. The chosen machining strategy also plays a crucial role in the tool’s lifespan and the quality of the machined surface, making it essential to select the appropriate strategy. Hence, the authors have opted for two conventional trochoidal strategies, namely the circular and swinging toolpath, along with a contemporary toolpath known as the Autodesk Inventor HSM Adaptive strategy. The authors investigated the effects of technological parameters and toolpaths on cutting forces, tool wear, surface roughness and burr formation on machined edges. The results show that lower cutting parameters and adaptive strategies lead to the smallest tool loads, tool wear, the best quality of surface roughness and burr formation on machined edges.

The turning process plays a crucial role in defining the mechanical properties and surface integrity of manufactured components. This study investigates the influence of turning factors—cutting speed, feed rate, and depth of cut—on the material removal rate (MRR) and surface roughness parameters (Ra and Rz) of material extrusion (MEX)-fabricated parts. A Box-Behnken Design (BBD) was employed to systematically assess the significance of these factors, and analysis of variance (ANOVA) was conducted to quantify their effects. The results revealed that feed rate was the most dominant factor affecting surface roughness, contributing 93.89% to Ra and 87.90% to Rz, while both feed rate and depth of cut significantly influenced MRR. Contour plots were generated to visualize the interactions between process factors and response variables. Regression models were developed to predict the responses, achieving high accuracy with coefficient of determination (R ²) values of 99.3% for MRR, 98.7% for Ra, and 98.8% for Rz, confirming their reliability. The optimization results identified the optimal turning conditions as 150 m/min cutting speed, 0.140172 mm/rev feed rate, and 1.5 mm depth of cut, ensuring enhanced material removal efficiency while maintaining surface quality. These findings provide valuable insights for optimizing the turning process of MEX parts, paving the way for improved manufacturing precision and efficiency.

In this study, the effects of cutting speed and feed rate on the roughness parameters R_a, R_z, R_sk, R_ku, R_pk, R_vk, and A₂ were examined during machining with coated carbide tools in a dry environment. The authors introduced the R_vk/R_pk ratio, a coefficient that facilitates a simpler evaluation of surface wear resistance. Specifically, if this ratio is greater than 1, the surface is more wear-resistant, while values less than 1 indicate a higher tendency for surface wear. The Taguchi OA method was used to analyze and identify the significance of technological parameters on output characteristics. Based on the results, it was established that feed rate has the greatest impact on all output characteristics. The highest cutting force was measured at a cutting speed of 60 m/min and a feed rate of 0.15 mm/rev, attributed to the fact that at lower cutting speeds, the base material does not soften while the cross-sectional area of the chip increases. To achieve the lowest R_a and R_z surface roughness, a cutting speed of 100 m/min and a feed rate of 0.05 mm/rev are recommended. If the goal is to enhance surface wear resistance and improve oil retention capability, machining with a cutting speed of 80–100 m/min and a feed rate of 0.15 mm/rev is advisable, as the coarser machining increases both the R_vk/R_pk ratio and the oil-retaining pocket size, which together improve the wear resistance of the machined surface.

Cooling–lubricating processes have a big impact on cutting force, tool wear, and the quality of the machined surface, especially for hard-to-machine superalloys, so the choice of the right cooling–lubricating method is of great importance. Nickel-based superalloys are among the most difficult materials to machine due to their high hot strength, work hardening, and extremely low thermal conductivity. Previous research has shown that flood cooling results in the least tool wear and cutting force among different cooling–lubricating methods. Thus, the effects of the flood oil concentration (3%; 6%; 9%; 12%; and 15%) on the above-mentioned factors were investigated during the slot milling of the GTD-111 nickel-based superalloy. The cutting force was measured during machining with a Kistler three-component dynamometer, and then after cutting the tool wear and the surface roughness on the bottom surface of the milled slots were measured with a confocal microscope and tactile roughness tester. The results show that at a 12% oil concentration, the tool load and tool wear are the lowest; even at an oil concentration of 15%, a slight increase is observed in both factors. Essentially, a higher oil concentration reduces friction between the tool and the workpiece contact surface, resulting in reduced tool wear and cutting force. Furthermore, due to less friction, the heat generation in the cutting zone is also reduced, resulting in a lower heat load on the tool, which increases tool life. It is interesting to note that the 6% oil concentration had the highest cutting force and tool wear, and strong vibration was heard during machining, which is also reflected in the force signal. The change in oil concentration did not effect the surface roughness.