Surface Finish Of Machined Workpiece Research Articles

Dry turning of hard 2379 steel using a ZTA5Ce0.7La ceramic cutting insert: A study

The aim of this work is to evaluate the dry turning ability of zirconia toughened alumina reinforced with 5 wt.% CeO2 and 0.7 wt.% La2O3 (ZTA5Ce0.7La) ceramics as cutting insert in turning of 2379 steel with hardness of 43 HRC. Triangular cutting inserts were fabricated using this material composition via powder metallurgy route. Results of the cutting insert were measured based on the average width of flank wear and surface finish of machined workpiece. Results show that the tool was able to machine tool steel and good surface finishes were obtained for most of the cutting speeds used in the machining test, except for the highest cutting speed of 237.5 m/min. The longest life (12.5 minutes) of the cutting inserts according to the measured flank wear for the turning at cutting speed of 87.1 m/min with considerably good surface finish (Ra of 0.778 μm). Therefore, this ZTA5CeO0.7La cutting inserts is possible to be used as a successful dry turning process of 2379 steel.

DECODING OF THE RELATIONSHIP BETWEEN COMPLEX STRUCTURES OF MACHINED SURFACE AND TOOL WEAR IN MILLING OPERATION

Surface finish of machined workpiece is one of the factors to evaluate the performance of machining operations. There are different factors such as machining parameters that affect the surface finish of machined workpiece. Tool wear is an unwanted machining issue that highly affects the surface finish of machined workpiece. In a similar way, different parameters (e.g. cutting speed, feed rate and depth of cut) also affect tool wear. In this research, we investigated how the complex structure of machined workpiece is related to the complex structure of tool wear. For this purpose, we benefited from the fractal analysis. The experiments were conducted based on the variations of machining parameters (depth of cut, feed rate and spindle speed), and accordingly the fractal dimension of machined surface was analyzed versus the fractal dimension of tool wear. Based on the obtained results, the complexity of machined surface is related to the complexity of tool wear. Fractal analysis could be applied to other machining operations to analyze the complex structures of machined surface and tool and potentially make a relationship between them.

FRACTAL-BASED ANALYSIS OF THE RELATIONSHIP BETWEEN THE SURFACE FINISH OF WORKPIECE AND CHIP FORMATION IN MILLING OPERATION

Surface finish is one of the most important issues that is discussed in machining of materials. In fact, reaching the required surface finish is the key scale in analysis of the quality of machined workpiece. Chip formation is an important factor that highly affects the surface finish of machined workpiece. In this research, we analyze the relationship between surface finish and chip formation by fractal analysis of their surfaces. Since both patterns have complex structures, we calculate their fractal dimension in case of different experiments in which machining parameters change. The result of analysis indicates that the variations of fractal dimension of machined surface show a reverse pattern compared to the fractal dimension of chip surface in case of variations of depth of cut and feed rate. However, in case of variations of spindle speed, the variations of fractal dimension of machined surface show a similar pattern with the fractal dimension of chip surface. Therefore, it can be said that the complexity of machined surface is linked to the complexity of chip surface. The method of analysis used in this research can be further applied to other manufacturing operations.

FRACTAL-BASED ANALYSIS OF THE RELATION BETWEEN THE FRACTAL STRUCTURES OF MACHINED SURFACE AND TOOL WEAR IN TURNING OPERATION

Obtaining the optimum surface finish is one of the key factors in machining operations. For this purpose, engineers apply a set of machining parameters to obtain the desired surface quality. On the other hand, tool faces wear during machining operation that itself affects the surface quality of machined surface. Therefore, tool wear and surface finish of machined workpiece should be related to each other. In this research, we employ fractal analysis in order to investigate the correlation between variations of complex structure of machined surface and tool wear in turning operation. In fact, we changed the machining parameters between different experiments and investigated how the machined surface is correlated with the tool wear. Based on the obtained results, we can see the correlation between the complexity of machined surface and tool wear by increasing the depth of cut, spindle speed and feed rate in different experiments. The method of analysis employed in this research can be widely applied to other machining operations in order to find the correlation between the surface quality of machined surface and tool wear.

COMPLEXITY-BASED DECODING OF THE EFFECT OF MACHINING PARAMETERS ON THE MACHINED SURFACE IN MILLING OPERATION

Acquiring the desired surface quality is one of the major efforts in machining of materials. Milling operation is a widely used machining operation to shape the material in different forms. Machining parameters and conditions are two major factors that affect the surface quality of machined workpiece in milling operation. In this paper, we analyze the surface finish of machined workpiece under the variations of machining parameters and conditions (wet and dry conditions) in milling operation. For our analysis, we use fractal dimension as the indicator of complexity of structure. Based on the obtained results, in the case of wet machining condition, by increasing the depth of cut, feed rate and spindle speed in separate experiments, the fractal dimension of machined surface increases. However, the obtained results in the case of dry machining condition are not consistent with the variations of different machining parameters. The obtained results will be discussed in terms of complex structure of machined surface. The method of analysis employed in this research can be investigated with other machining operations to check how the machining parameters and conditions affect the surface quality of machined surface.

Modelling of orthogonal cutting of stainless steel using carbide tool

Machine elements with cylindrical shapes in equipment like hydraulic jacks are bound to fail in operations due to craters formed on their surfaces. The surface finish of machined workpiece is determined by the possibilities of minimizing surface roughness. Although the absolute value of the average surface roughness has been the focus of experimental investigations yet it cannot provide all the information regarding the surface texture. The aim is to develop suitable models for the prediction of responses from orthogonal metal cutting process and the purpose is to provide a framework that can serve as guide for indigenous machinist. Box-Behnken design based on Response Surface Methodology was adopted for the experiment which was carried out on a ENC centre lathe machining centre. Non-linear quadratic regression models were developed based on the set machining parameters and their lack-of-fit test was carried out at 0.05 level of significance.Keywords: Orthogonal Metal Cutting; Surface Roughness; Tool-life; Surface Finish; Machining Time

FRACTAL-BASED ANALYSIS OF THE EFFECT OF MACHINING PARAMETERS ON SURFACE FINISH OF WORKPIECE IN TURNING OPERATION

Analysis of workpiece surface quality is one of the major issues in manufacturing engineering. Turning operation is a famous machining operation that is widely used in machining of materials. In this research, we investigate the surface finish of machined workpiece from turning operation. For this purpose, we employ fractal theory to study the complex structure of machined workpiece’s surface in different conditions. The applied parameters include the variations of cutting depth, feed rate and spindle speed in wet and dry machining conditions. Based on the obtained results, we found the correlation between the increment of fractal dimension of machined surface and the increment of cutting depth, feed rate and spindle speed in wet machining condition. The obtained results will be discussed in relation with the complexity of machined surface. The employed method of analysis in this research can be widely applied to the analysis of the effect of different machining parameters and conditions on the surface quality of machined workpiece in case of different machining operations.

Development of electrostatic solid lubrication system for improvement in machining process performance

Liquid lubricants have traditionally been used to control the high heat generation in machining; however, the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. Minimization or possible elimination of cutting fluids substituting their functions by some other means is emerging as a thrust area of research in machining. Solid lubricant assisted machining is a novel concept to control the machining zone temperature without polluting the environment. The focus of this study is to explore the possibility of application of graphite as a lubricating medium in drilling of AISI 4340 steel, as a means to reduce the heat generated due to friction, towards finding an alternative to conventional coolants. To this end, an optimized solid lubricant application method, electrostatic solid lubrication experimental setup has been envisaged for effective supply of solid lubricant mixture as a high velocity jet and at an extremely low flow rate to the machining zone, thus meeting environmental requirements. The process performance is judged in terms of thrust force, tool wear, chip thickness, hole diameter and surface finish of machined workpiece keeping the other conditions constant. A comparison with the results obtained in wet and dry machining is also provided. The results obtained from the experiments show the effectiveness of the use of the solid lubricant as a viable alternative to wet and dry machining through reduction in the cutting zone temperature and favourable change in chip–tool and work–tool interaction. The proper selection and application of solid lubricant can lead to low cost, and this concept could emerge as an effective alternative to conventional coolants.