Feasibility Study of Adopting Minimal Quantities of Lubrication for End Milling Aluminium

End milling is a very common metal cutting process used for the machining of most types of metal. The process is inherently intermittent causing the tool tip edge to constantly fluctuate between various levels of temperatures, specifically from cold to 300oC when cutting Al alloy. During dry end milling cutting temperatures need to remain within the design specifications of the tool tip. Even working with Al alloy the tool tip is subjected to thermal cyclic stresses. Conventional wisdom states that it is essential to use flood cooling during end milling, as intermittent cooling increases the effect of thermal shock and build up edge. Al alloy - unlike other materials - needs cutting fluid to avoid smearing the insert edges and to improve the surface finish. Modern machining companies constantly face the challenges of environmental issues that affect the manufacturing costs of machined parts. New environmental manufacturing techniques need to be developed for companies to remain competitive in the future. The research presented in this paper represents the experimentation involved in determining a suitable environmental alternative to using copious amounts of cutting fluid during end milling of Al alloy. Previous experimental evaluation of Minimal Quantities of Lubrication (MQL) when applied to the machining of Al alloy has proved to be inconclusive

Machining of titanium alloys for medical application: a review

Titanium alloys for their characteristics have acquired a prominent position in numerous industrial applications. Due to its properties, such as high resistance to corrosion, reduced density, high specific strength and low Young's modulus, titanium alloys became indispensable as a biomaterial with high use in medical devices, with special emphasis in the area of orthopaedics. Problems associated with its manufacturing by conventional machining processes, such as milling, turning and drilling are well known and studied. Its low thermal conductivity, high chemical reactivity, high hardness at high temperatures make it classified as difficult to machine material. Despite the already extensive knowledge about machining titanium alloys problems, and the constant technological development to overcome them, it is not yet possible to machine this material like other metals. This work is based on research and review papers from Scopus and Scholar from 2010 to 2020 and addresses the main issues related to the machining of titanium alloys used in medical devices manufacturing and current solutions adopted to solve them. From the research consulted it was possible to conclude that it is consensual that for milling, turning and helical milling cutting speed can reach up to 100m/min and up to 40m/min in drilling. As for feed rate, up to 0.1mm/tooth for milling and helical milling and up to 0.3mm/tooth for turning and 0.1mm/rev for drilling. Also, that Minimum Quantity Lubrication is a valid and efficient solution to mitigate titanium alloys machining problems.publishe

A Micro-milling cutting force and chip formation modeling approach for optimal process parameters selection

Las últimas décadas evidencian una demanda creciente por componentes miniaturizados con dimensiones reducidas y tolerancias estrechas, lo cual ha conllevado al desarrollo de la micro y nanotecnología. El micro-fresado, dentro de los procesos de micro-mecanizado, tiene el potencial de ser uno de los procesos de remoción de material más costo-efectivos y eficientes debido a su facilidad de aplicación, variedad de materiales de trabajo y flexibilidad geométrica. Se enfrenta a unos retos complejos debido al efecto de tamaño, vibraciones y otros factores incontrolables. Este estudio analiza dicho proceso orientado hacia desarrollar una mejor comprensión de la mecánica del micro-corte para ser aplicada en la optimización de parámetros de proceso. Se propone un acercamiento al modelado híbrido en forma novedosa, que permite una evaluación numérica a priori para evaluación de fuerzas y esfuerzos, combinado con experimentación para evaluar parámetros relevantes a la industria (formación de rebabas, desgaste de herramientas, entre otros).DoctoradoDoctor en Ingeniería Mecánic

Micromachining of Advanced Materials

Market needs often require miniaturized products for portability, size/weight reduction while increasing product capacity. Utilizing additive manufacturing to achieve a complex and functional metallic part has attracted considerable interests in both industry and academia. However, the resulted rough surfaces and low tolerances of as-printed parts require additional steps for microstructure modification, physical and mechanical properties enhancement, and improvement of dimensional/form/surface to meet engineering specifications. Micromachining can (i) produce miniature components or microfeatures on a larger component, and (ii) enhance the quality of additively manufactured metallic components. This chapter suggests the necessary requirements for successful micromachining and cites the research studies on micromachining of metallic materials fabricated by either traditional route or additive technique. Micromachining by nontraditional techniques—e.g., ion/electron beam machining—are beyond the scope of this chapter. The chapter is organized as following: Section 1: Introduction; Section 2: Requirement for successful micromachining: cutting tools, tool coating, machine tools, tool offset measuring methods, minimum quantity lubrication, and size effect; Section 3: Effect of materials: material defects, ductile regime machining, crystalline orientation, residual stress, and microstructure; Section 4: Micromachining: research works from literature, process monitoring, and process parameters; Section 4.1: Micromilling; Section 4.2: Microdrilling; Section 4.3: Ultraprecision turning; Section 5: Summary; and References

Evaluation of Workpiece Temperature during Drilling of GLARE Fiber Metal Laminates Using Infrared Techniques: Effect of Cutting Parameters, Fiber Orientation and Spray Mist Application

The rise in cutting temperatures during the machining process can influence the final quality of the machined part. The impact of cutting temperatures is more critical when machining composite-metal stacks and fiber metal laminates due to the stacking nature of those hybrids which subjects the composite to heat from direct contact with metallic part of the stack and the evacuated hot chips. In this paper, the workpiece surface temperature of two grades of fiber metal laminates commercially know as GLARE is investigated. An experimental study was carried out using thermocouples and infrared thermography to determine the emissivity of the upper, lower and side surfaces of GLARE laminates. In addition, infrared thermography was used to determine the maximum temperature of the bottom surface of machined holes during drilling GLARE under dry and minimum quantity lubrication (MQL) cooling conditions under different cutting parameters. The results showed that during the machining process, the workpiece surface temperature increased with the increase in feed rate and fiber orientation influenced the developed temperature in the laminate

Review on machining of additively manufactured nickel and titanium alloys

The machining of nickel and titanium-based superalloy components is very expensive and involves unusually high lead times compared with other engineering metals such as steels and aluminum. This has led to the development of most suitable additive manufacturing (AM) processes to fabricate these difficult-to-machine metals into near-net shape parts, thereby reducing the lead time and material waste, and significantly increasing productivity. Nonetheless, finish machining is still required on the AMed metal components to meet the dimensional and surface requirements of the application. Several research studies have investigated the machinability of AMed nickel and titanium alloy workpieces and have compared the results with the machining responses of wrought counterparts, which is detailed in this review. The categorization of the literature is based on the machining operations including turning, milling, drilling, and non-conventional machining, and the observations are discussed in accordance with various input parameters such as workpiece characteristics (hardness, microstructures) and anisotropy in mechanical properties due to build orientations during the AM process. Moreover, the influence of these parameters on cutting forces and temperatures, chip formation, and tool wear is analyzed and reported. From this review, it is found that the machinability of AMed nickel and titanium workpieces is quite different to the machining responses of their wrought counterparts. Further thorough experimentation is required to develop optimized machining parameters for AMed metal parts, while an exploration of different cutting tool geometries, coolant, and lubrication strategies for enhanced tool performance for machining AMed workpieces is essential. Finally, this study reviews the state of contemporary research, and offers suggestions for future research

An experimental study on MQL assisted high speed machining of NiTi shape memory alloy

Abstract: Nickel Titanium (NiTi) shape memory alloy is a prominent material for biomedical implants. Machining of shape memory alloy is challenging and requires intervention of sustainable techniques to produce quality products with minimum environmental footprints. This paper details the results of experimental investigation conducted on MQL assisted high speed machining of shape memory alloys. It reports the effect of MQL parameters on surface roughness and tool wear during turning (at speed 90 m/min) of NiTi shape memory alloy. Experiments are conducted based on Taguchi’s robust design of experiment technique with L9 orthogonal array. Rhomboid shaped simple carbide tool is selected for experimentation. Green lubricant which is a blend of natural, synthetic and sulphurized esters is used as MQL fluid. Three important MQL parameters such as flow rate, air pressure, and nozzle distance are varied at 3 levels each. Parameters are optimized to secure the optimum combination producing best surface finish (Ra~1.39μm) and tool flank wear 1.6 mm