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Machining of CFRP composites is usually described as a challenging process from tool life and surface quality perspectives. To achieve a flawless machined surface at reasonable cutting tool life/cost, an optimum combination of cutting tool material and geometry is the key. The cutting tool angles are of importance as these dictate the cutting mechanism as well as the cutting edge robustness and the introduction of vibration to the machining process opens up new horizons of improvement and stirs further research questions. This article investigates the effect of tools with different geometry possessing different rake angles when used in ultrasonic-assisted edge trimming operation dealing with multidirectional CFRP laminates. A full-factorial experimental design was adopted to analyze the effect of process parameters typically cutting speed, feed rate, rake angle, amplitude, and their interactions. Machining performance indicators were captured which were the cutting forces, tool wear, chip temperature, and surface roughness. The results showed that UAM mode contributed to an increase in the cutting forces, tool wear, and chip temperature compared to the conventional mode. On the other hand, UAM mode improved the quality of the machined surface. Additionally, the ultrasonic mode enhanced the material removal mechanism using a tool with a negative rake angle. [ABSTRACT FROM AUTHOR]

Aluminum alloys 6061-T6 are widely utilized in the automotive, aerospace, and marine industries due to high corrosion resistance, high strength, and good workability and machinability. The machining performance of these alloys depends on several factors including tool's material, coating, and geometry. Cutting tool edge radius is one of the most effective factors in cutting forces, energy requirement, and chip formation during metal cutting. The present article aims to study the interactions between the cutting edge radius and cutting speed, feed rate, and rake angle and examine the impacts of the aforementioned tool geometry and cutting conditions on machining forces, cutting temperature, and chip thickness in cutting an aluminum alloy 6061-T6. Special attention is devoted to examining the influence of the cutting edge radius on machining variables and comparing the results of conventional machining (CM) and high speed machining (HSM). A finite element model was developed to simulate the above interactions and was experimentally validated for different machining parameters. The results demonstrate that although increasing the cutting edge radius clearly raises the machining forces, it has a slight influence on the chip thickness. It is also found that the maximum cutting temperatures remain nearly constant with changes in the tool edge radius, while the average temperatures of the tool tip increase especially in HSM. Furthermore, it was found that the location at which the maximum cutting temperature occurs depends more on cutting conditions and tool geometry than workpiece and tool materials. [ABSTRACT FROM AUTHOR]

The hard turning process is generally performed by PCBN or mixed ceramics tools, which have the mechanical properties that withstand the tribological conditions of the process imposed by the hardened machined material. Coated cemented carbides are also an option for hard machining processes, although relying on the coating deterioration. This paper aims to evaluate the tool wear rate in function of the cutting speed in the hard turning of the steel AISI 52100 with a hardness of 50 HRC for three different types of cutting tool materials: coated cemented carbide, mixed ceramic, and PCBN. The methodology applied to assess the tool wear is based on three-dimensional parameters (volumetric) obtained from a focus variation microscope (FVM). The tool wear rate (WRRM) is calculated based on ordinary least squares (OLS) adopting five values of WRM in five machining time intervals. The face turning experiments were performed at four cutting speeds: vc = 120, 150, 187.5, and 234 m/min. At vc = 120 m/min, the PCBN presented the lowest tool wear rate (182 μm3/s); at vc = 150 m/min, the coated cemented carbide (tool wear rate on the coating) had the best performance (417 μm3/s). The mixed ceramic tool presented a better performance at the higher cutting speeds of vc = 187.5 and 234 m/min, 1206 and 1878 μm3/s, respectively. The methodology applied was reliable to understand and discuss the performance of the machining process through the tool wear rate (WRRM), which is based on the volume of removed material from the tool (WRM). The three-dimensional tool wear parameters can also be applied to machining process optimization, cutting tool wear model creation, benchmarking, and development of new cutting tool materials and grades. Furthermore, the methodology can be considered more agile and precise when compared to the current industrial methodology of tool performance evaluation. Thus, this innovative methodology promotes important information for cutting tool manufacturers and for its customers such as automotive and aeronautic industry. [ABSTRACT FROM AUTHOR]