This paper focuses on turning a commonly used industrial plastic, unreinforced polyoxymethylene copolymer (POM-C), using a cutting tool made of polycrystalline diamond (PCD). Conducted experimental ...investigation was the basis for the analysis of the influence of cutting parameters on cutting energy, determination of specific cutting energy and construction of specific cutting energy consumption maps, the analysis of the relationship between the specific cutting energy and the un-deformed chip thickness, the evaluation of the machinability, and the analysis of cutting energy considering machinability. A multi-objective optimization problem with cutting energy and MRR as conflicting objective functions was also studied and solved using two optimization approaches. Observed correlations between cutting parameters and cutting energy or specific cutting energy are different compared to other studies that analysed different standard engineering materials. The depth of cut turned out to be the key cutting parameter for the achievement of a trade-off between the cutting energy and MRR. Variable influences of the feed rate and the cutting speed on cutting energy and specific cutting energy, depending on the depth of cut value, are also observed. Chip form turned out to be the prevalent criteria for the evaluation of unreinforced POM-C machinability. There is a combination of cutting parameter ranges and the range of cross sectional ratio (ratio of the depth of cut and feed rate) which ensure formation of favourable chip forms. Optimization of cutting parameter values can lead to substantial energy savings in removing a unit volume of unreinforced POM-C, either by observing only the cutting energy or by including the consideration of the machinability.
•Depth of cut enables trade-off between cutting energy and material removal rate.•The developed specific cutting energy maps could serve process planners.•Referential specific cutting energy for turning of POM-C using PCD tool determined.•Cross sectional ratio range ensuring formation of favourable chip forms determined.•Chip form is the prevalent criteria for the evaluation of POM-C machinability.
When turning titanium alloys, it is difficult to ensure the required quality with maximum machining efficiency. A typical problem in the turning process of titanium alloys is to achieve effective ...breaking and removal of chips from the machining zone. The combination of the new construction of cutting tools and machining methods in the machining of titanium alloys increases the efficiency of the machining. For this reason, the use of tools typical for the Prime Turning method in combination with the high-pressure cooling (HPC) method was analysed. The longitudinal turning of the Ti6Al4V ELI titanium alloy was performed using Sandvik Coromant grade 1115 carbide tools. An increase in the pressure of the cutting fluid to p = 70 bar was used. Measurements of the components of the total cutting force for finishing machining with variable cutting parameters in the range of: feed rates f = <0.1;0.4> mm/rev, cutting depth ap = <0.25;1.0> mm and cutting speed vc = <40;80> m/min were performed. It has been shown that the values of cutting force are mainly dependent on the feed and the depth of cut. An analysis of the forms of chips obtained is presented. The dependence of the applied cutting parameters on the value of the chip breakage coefficient Cch was determined. The method of searching for the maximum efficiency of the turning process was determined, taking into account the desired value of the chip breakage coefficient.
The transition in temperature and associated stress induced during machining, may affect the structural integrity of the Al7075-T6 alloy. In the present study, Steinberg Guinan material parameters ...were used to investigate the dynamic behaviour viz chip morphology (fracture mechanism), temperature change and flow stress in the elasto-visco material Al7075-T6. An explicit algorithm, was adopted to investigate the outcomes. Results showed chip formation and the mode of fracture was closely related with depth of cut and can influence the temperature and flow stress during the machining process. Work hardening and edge dislocation slip in the secondary shear zone was observed to have a notable influence. An optimal machining condition was found between 0.6 and 0.7 mm depth of cut.
Inconel 600 is classified as hard-to-cut material due its inherent characteristics such as high hardness and hardness, resistance to corrosion and oxidation. So, this alloy is suitable specially for ...chemical, heat-treating, aeronautics and nuclear industries. In this research work focuses on experimental investigation for the varying cutting speed on temperature, surface finish, insert and chip form while turning Inconel 600 using TiAlN coated cutting insert. Turning operation was carried out with variable cutting velocities (m/min) of 25, 38, 62 and 102, feed (mm/rev) of 0.12 and depth (mm) of 1. A lowest surface roughness value was observed on the turned Inconel 600 alloy surface for the cutting velocity of 102 m/min. An adhesion of chip on the cutting inserts were observed during turning of Inconel 600 alloy for the cutting velocities (m/min) of 25, 38 and 62. In all the cutting trials, the chips obtained were long and continuous in nature.
Experimental cutting tests on C45 carbon steel turning were performed for sensor fusion based monitoring of chip form through cutting force components and radial displacement measurement. A Principal ...Component Analysis algorithm was implemented to extract characteristic features from acquired sensor signals. A pattern recognition decision making support system was performed by inputting the extracted features into feed-forward back-propagation neural networks aimed at single chip form classification and favourable/unfavourable chip type identification. Different neural network training algorithms were adopted and a comparison was proposed.
The dynamic stability of the machining set and the entire cutting process, together with the appropriate form of chips generated during machining under the given conditions, are the basic ...prerequisites for autonomous machining in accordance with the Industry 4.0 trend. The research, based on a newly designed method, aims to study the frequency response of the machining system to different values of tool wear and cutting speed, which cause the worsening of the machined parts’ quality and the instability of the whole cutting process. The new idea is based on the inverse principle, in which the wear with various values of VB was artificially prepared in advance before machining. Consequently, the effect of artificial wear and cutting speed on vibration and chip shape characteristics were studied. Three types of brass alloys were used within the experiments as the machined materials. Measured data were statistically processed and the desired dependencies were plotted. Chips were collected for each combination of machining conditions, while the article presents a database of the obtained chip shapes at individual cutting speeds so that they can be compared and classified. The results showed that brass alloys CW510L and CW614N exhibit an average of three times lower vibration damping compared to the CW724R alloy, while relatively good chip formation was noted in the evaluated machining conditions even without the use of a chip breaker. The problematic chip shape occurred only in some cases at the machining of CW510L and CW724R, which cannot be generalized.
Turning is a complex machining process that can be characterized by a number of performances for a given machining system, workpiece material, cutting tool, and selected cutting regime. In addition ...to the characteristics of the machined surface quality, the estimation of machining time is particularly important for manufacturers, since machining time is directly related to other important performances of the turning process, such as productivity, cost, and energy consumption. In this paper, a model for estimation of total operation time in turning of a part with continuous profile, made of polyoxymethylene copolymer (POM-C), using a polycrystalline diamond (PCD) cutting tool, was developed. Face centred central composite design (CCD) and Box–Cox transformation approaches were applied for that purpose. The developed model was then used as the objective function in the proposed optimization model, which also included three practical constraints related to quality of the machined surface (surface roughness and workpiece deflection) and machinability aspects of the workpiece material (favourable chip forms). Nonlinear and linear models, used as constraints, were developed based on the results of experimental investigation of turning of POM-C using a PCD cutting tool. The total operation time estimation model showed good agreement with the results of tool path simulations in CAM software and validation experimental trial in real manufacturing environment. By applying the optimal solution, 44% of the total time being saved for machining of a single part can be achieved, compared to the recommended cutting parameter values, which indicates significant optimization benefits in turning industrial plastics.
The paper presents the results of turning tests of Ti6Al4V alloy with a sintered carbide tool. For selected sets of cutting data, two kinds of coolant supply were compared. Conventional coolant ...supply with the pressure of 7 bar was compared with HPC (High - Pressure Coolant) system working with the pressure of 70 bar. The tests revealed the fact that HPC system is useful for small values of feed taking into account chip form. Photographs of chips and their form analysis are presented. The results of tests performed by Sandvik Coromant concerning turning stainless steel were compared and discussed.
The aim of this study is to reveal how ZrO
2
(zirconia) contributes to the machinability of aluminum 1050. In the first stage of this study, composite materials were produced by the vortex method by ...adding different amounts of ZrO
2
(5%, 10%, 20%, and 30%) into commercial aluminum of 99.5% purity. Then, microstructure images of composite materials were taken under the scanning electron microscope (SEM), and the hardness of these composite materials was measured. In the last stage, the machinability tests of the composite materials were performed on the lathe under dry machining conditions at 125, 175, and 225 m/min cutting speeds and 0.03–0.06 and 0.12 mm/rev feed rates, with 1.5 mm constant depth of cut. Uncoated cementite carbide cutting tool inserts were used in machining tests. SEM images of the cutting tool inserts were taken, and the roughness values of the machined surfaces were measured. Chip samples were taken and investigated. It was observed that all the cutting tools had a Built-Up Edge (BUE) formation. Surface roughness and BUE formation increased as the feed rates were increased and decreased with increasing cutting speed. The roughness values decreased slightly and then increased again depending on the ZrO
2
ratio. As the feed rates increased, a transition from ribbon chip type to the helical and saw-toothed forms was observed. It was also observed that the chip formation changed depending on the amount of ZrO
2
in the composite structure.
The mechanism of serrated chip formation during high-speed turning of Inconel 718 using PCBN cutting tools has been investigated with the aid of scanning electron microscopy and optical microscopy. A ...conceptual model of chip formation has been developed knowing the chip morphology. It is followed by the analysis of chip segmentation frequency and the chip forms. Further, the chip segment forms and geometry were quantitatively characterized as a function of machining parameters and the cutting edge geometry using statistical methods. The chip morphology has been correlated with the cutting forces, specific shearing energy and the resultant roughness of the machined surfaces.
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