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Correlation between Coating Properties and Industrial Applications
Published in Sam Zhang, Jyh-Ming Ting, Wan-Yu Wu, Protective Thin Coatings Technology, 2021
Yin-Yu Chang, Heng-Li Huang, Jui-Ting Hsu, Ming-Tzu Tsai
In recent years, a broad growing market of coated cutting tools has been developed, and the hard coatings of cutting tools were driven by the demand on the increased usage of difficult-to-cut materials. In the case of cutting difficult-to-cut materials of Inconel super alloy, a nickel-based alloy which is difficult to shape because of its high tribological and thermal properties. Erosion of the cutting edge occurs due to diffusion wear after abrasive wear. Decrease of cutting force and limitation built-up edge (BUE) phenomenon are necessary. AlTiN coating possessing high temperature oxidation resistance shows good tribological behavior and it prevents sticking phenomena on rake face of the cutting tool. Microabrasive blasting can be adopted as a surface modification as well as the AlTiN coating treatment technique [58]. Sanchette et al. [59] showed that a nanolayered TiN/AlTiN coating is a proper coating design for cutting Inconel alloys. This coating induces the lowest cutting force on the tool and limits adhesive BUE phenomenon. This coating is also very effective for avoiding strong abrasive wear due to high hardness and toughness of the coating material.
Tool Wear and Tool Life
Published in David A. Stephenson, John S. Agapiou, Metal Cutting Theory and Practice, 2018
David A. Stephenson, John S. Agapiou
Edge buildup (Figures 9.1g and 9.9) most often occurs when cutting soft metals, such as aluminum alloys, at low cutting speeds. It results when metal adheres strongly to the cutting edge, building up, and projecting forward from it. As discussed in Section 9.10, buildup is also a serious problem in drilling operations; it may occur at the outer corner of the spiral point drills because the chip becomes thin at this point. Built-up edge (BUE) formation is undesirable because it changes the effective depth of cut (or hole diameter) and because it is often unstable, leading to poor surface finish and tool chipping. The mechanics of BUE formation is described in Section 6.14. BUE formation can be minimized by using a more positive rake angle, tools with smooth surface finishes (<0.5 µm Ra), coolant with increased lubricity, higher pressure coolants directed on the rake face, and higher cutting speeds.
Investigation on the built-up edge process when dry machining aeronautical aluminum alloys
Published in Diego Carou, J. Paulo Davim, Machining of Light Alloys, 2018
Mohammed Nouari, Badis Haddag, Abdelhadi Moufki, Samir Atlati
Despite the large number of works on machining aluminum alloys, the understanding of the effect of friction conditions requires further investigations. It is well known that with increasing friction, tool wear increases, especially when dry machining of aluminum alloys. Consequently, the surface integrity and the machined components can be strongly influenced by the tribological conditions. The former can also affect the chip formation process (Mabrouki et al. 2016; Nouari et al. 2005). The accumulation of debris generated by this process and deposited on the tool surface during machining induces the formation the built-up edge (BUE). Several authors describe this phenomenon as a wear mechanism. From an experimental point of view, some authors noted that the BUE is significantly affected by the state of stress around the tool cutting edge and happens under extreme conditions of the contact at the tool–chip interface as high friction, high pressure, and sliding velocity. Kone et al. (2011) reported that this phenomenon can be attributed to the brittle behavior of the machined material and the temperature gradient on the tool surface. Other authors showed that the BUE is the consequence of seizure and sublayer flow material at the tool–chip interface. The strain hardening of the workpiece material promotes the formation of a stagnant build-up around the cutting edge. Iwata and Ueda (1980) analyzed scanning electron microscopy images and observed a local deformation around the BUE area for low-carbon steels. Using electron probe microanalysis and electron diffraction, Ramaswami (1971) and Ohgo (1978) showed that adhesion wear has an effect on the BUE and tool wear, which depends directly on cutting conditions. Also, Selvam and Radhakrishnan (1974) investigated different groove tool profiles and analyzed the effect of generated wear on the BUE adhering to the machined surface.
The effects of coolant on the cutting temperature, surface roughness and tool wear in turning operations of Ti6Al4V alloy
Published in Mechanics Based Design of Structures and Machines, 2023
The surface roughness of machined workpiece with coolant is decreased in comparison to the dry turning operations of Titanium alloy Ti6Al4V. The built-up edge (BUE) is generated during dry machining which can cause cutting tool inserts to drag over the surface of machined components and can decrease the surface quality of machined parts (Patel and Patil 2022). The coolant reduces cutting temperature in the contact zone of the cutting tool and workpiece and prevents the formation of BUE which can increase the surface quality of machined components. In order to obtain the amount of tool wear using the calculated cutting forces at each point of the cutting tool throughout turning operations, the geometry of the cutting tool is subsequently modified during finite element modeling of cutting tool using the developed virtual machining system in the study. The simulated cutting tool flank wear after 14 min of Titanium alloy Ti6Al4V turning operation is shown in the Figure 14.
Machinability analysis and application of response surface approach on CNC turning of LM6/SiCp composites
Published in Materials and Manufacturing Processes, 2019
Balasubramanian K, Nataraj M, Palanisamy Duraisamy
The crater and flank wear are described as the vital measures of the life of tool, and it depends on machining conditions, hardness of the work specimen, geometry of tool, and also type of tool.[24]The reinforced silicon carbide particles are harder than tungsten carbide insert) and behave like a cutting edge during machining of MMC. The SEM and EDAX analysis for LM6/SiC MMC are presented in Fig. 9. The work piece has been stick over the rake face of the cutting inserts in machining of MMC. During machining, the ductile property of MMC generated high shearing stress and temperature evolved at the secondary malformation region especially at the chip-tool interface region. The work material adhered or built-up-edge (BUE) due to high stress, cutting pressure, and temperature among the cutting tool insert and work-piece.[25] This adhesion property of work material is accelerated at lower machining velocity, because at lower machining velocity higher cutting force and higher cutting temperature is produced.[26]The formation of built-up-edge deteriorated the surface finish quality and increased the cutting force.[27]
Surface integrity in 3D ultrasonic vibration-assisted turning driven by two actuators
Published in Machining Science and Technology, 2023
Shiyu Wei, Ping Zou, Jingwei Duan, Kornel Ehmann
The use of the 3D-UVAT results in an oblique cutting process that has numerous advantages over orthogonal cutting. On the one hand, in oblique cutting, chips are not only easier to remove, preventing the machined surface from being scratched, but on the other, the lateral outflow of the chips also helps in reducing the friction resistance between the chips and the turning tool. The reduction of friction resistance helps in prolonging the life of the turning tool, reducing the generation of a built-up edge (BUE) and improving the surface quality of the machined workpiece.