International Journal of Machining and Machinability of Materials (5 papers in press)
Effects of cutting speed and milling method on cutting forces, tool wear, tool life, and surface roughness in high-speed shell milling of Inconel 718 with coated carbide insert under emulsion flood cooling strategy
by Anthony Chukwujekwu Okafor, Theodore Nwoguh
Abstract: Inconel 718 use in aerospace and nuclear industries has gained wide interest due to the need to improve its machinability. This paper presents the results of experimental investigation of the effects of face milling methods and cutting speed on machinability of Inconel 718 with carbide inserts under conventional emulsion flood cooling strategy (CEF-CS) as a benchmark for comparing alternative Vegetable-oilbased MQL Cooling Strategy (VO-MQL-CS). The machinability parameters investigated are cutting force components, tool wear, burr formation, surface roughness, and tool life, under up- and down-milling at cutting speeds of 30, 40, and 50 m/min and constant chip load. Lower cutting forces, tool wear, burr formation, surface roughness, and significant improvement in tool life and volume of material removed are achieved in down-milling over up-milling by 1,677%, 2,150%, and 1,004% at 30, 40, and 50 m/min respectively. Down-milling at 40 m/min cutting speed under CEF-CS with coated carbide inserts is recommended as benchmark.
Keywords: Inconel 718; Cutting forces; Up- and down-milling; Tool wear; Emulsion flood cooling; Surface roughness.
Preparation, characterization and testing of graphene self lubricated tungsten carbide tools for sustainable turning
by Amrita M, Kamesh Bodduru, Srikanth R R
Abstract: Cutting fluids are commonly used for cooling and lubrication in machining but are unsafe to environment and cause health problems in workers. Though dry machining can be used to eliminate this problem, it is not preferred, owing to high temperature and friction. Additives with higher thermal conductivity and lubricating properties can increase the cooling and lubricating capabilities of cutting tools. Present work aims to check the feasibility of preparing graphene self lubricated tungsten carbide tools using powder metallurgy and adding varying concentration of graphene. Prepared tool materials are tested for tribological and thermal properties. Both Inconel718 and Ti6Al4V are machined using graphene self lubricated tools. Addition of graphene in minute quantities to tungsten carbide tools enhanced the tribological and thermal properties and also showed improvement in turning performance.
Keywords: Sustainability; graphene; tungsten carbide; hardness; tribology; machining; Inconel718; Ti6Al4V.
Development and experimental validation of numerical formulations of a heuristic model in WEDM of H13 tool steel
by Meinam Annebushan Singh, Koushik Das, Deba Kumar Sarma
Abstract: Proper identification of the effect of various process parameters in wire-electrical discharge machining process is a very important area that needs a thorough analysis. Also, the advancement in technology has considerably limited the user interface. The knowledge of the interdependence of these parameters will prove to be an important criterion to further enhance the machining technique. The present work focuses on the thorough analysis of the effect of the interdependence of process parameters in machining of H13 tool steel. Experiments were performed to obtain the material removal rate for different conditions. A finite element based backtrack numerical solver is developed to simulate the working voltage with the experimental results. The analyses show the interdependence of voltage, current, pulse on and off-time. A power allometric based heuristic model is formulated to identify the parameters interdependence. The proposed heuristic model has been validated with the experimental results, performed at random parametric conditions.
Keywords: EDM; FEM; MRR; heuristic model; FEM; H13 too steel.
Cutting force, torque, and hole quality in vibration-assisted helical milling of AA7075
by Mariam Nabil Ali Mohamed, Hassan El-Hofy
Abstract: Recently, an ultrasonic vibration-assisted technique has been utilized to improve the hole-making process of aerospace materials. However, there was a lack in discussing the effect of applying ultrasonic vibration and different cutting conditions on the hole quality during vibration-assisted helical milling (VAHM). Therefore, this work experimentally and statistically investigated the impact of VAHM variables on the machinability of AA7075 alloy. The process parameters included axial helical pitch, tangential feed rate, ultrasonic vibration assistance, and different fluid supply techniques of dry, minimum quantity lubrication, and flood. The machining evaluation was performed by computing cutting force, torque, hole quality concerning hole diameter, out-of-roundness, hole conicity, burr height, and surface roughness. Analysis of variance (ANOVA) was conducted to determine the significant factors and their percentage contribution. The ultrasonic vibration was found to have an insignificant effect on hole diameter, and surface roughness; however, it reduces out-of-roundness, burr height, torque, and hole conicity.
Keywords: Ultrasonic vibration; Helical milling; AA7075 alloy; Cutting force; Hole accuracy; Burr height; Surface roughness.
Quality improvement in mechanical micro drilling of titanium alloy under dry conditions
by Somashekhar S. Hiremath, Prashanth P
Abstract: Titanium alloy (CpTi) grade II is considered a hard-to-cut material due to low thermal conductivity, work hardening behavior, and affinity with cutting tool materials. In this study, micro-holes are machined on titanium alloy (Cp Ti) grade II under dry conditions. Experiments are carried out by varying the machining parameters like cutting speed (5 m/min, 6.9 m/min, and 8.8 m/min), feed (5
Keywords: mechanical micro-drilling; exit burr height; taper angle; response surface methodology; exit thrust force; titanium alloy (Cp – Ti) grade –II.