Surface Quality Of Machined Workpiece Research Articles

Comprehensive Evaluation Study of Innovative Measurement Techniques in Surface Roughness within Manufacturing Processes

Abstract With the advancement of modern technology, numerous advanced methods for measuring surface roughness have emerged. These are categorized into contact and non-contact methods, such as optical, ultrasonic, and machine vision measurements. By researching and integrating various characteristics, including cutting parameters, vibration, and force signals, with workpiece texture images, a comprehensive model for predicting surface roughness is formed. These novel multidimensional feature prediction equations significantly enhance practicality and accuracy in assessing the surface quality of machined workpieces, marking a clear advancement over traditional measurement techniques.

Study on the influence of milling tool inclination angle on surface quality and optimal selection in the ultra-precision diamond milling of curved surfaces

During the milling of a curved surface, the shape of the curved surface changes continuously along the milling path, and the direction of the angle between the axis of the milling tool and the normal vector of the machined surface also changes. In turn, these changes greatly affect the quality of the machined surface. Therefore, to improve the surface quality of machined workpieces, the milling tool inclination angle should be optimized. In the present study, a three-dimensional model of the milling tool path and the workpiece surface was created. The three-dimensional surface model of the workpiece at each machining moment was iteratively built based on the Z-map method. From the macroscopic perspective, the influences of different milling tool inclination angles on surface roughness were analyzed. The difference in surface roughness generated by different inclination angles under the same feed rate and pitch was obtained. When cutting with the top of the milling tool, the roughness was larger compared to other inclination angles, and there was a roughness deviation of about 8% when other inclination angles were selected. Moreover, from the microscopic perspective, the material removal rate from a single feed cycle and the optimal inclination angle range for milling stability were explored. An optimal inclination range of 15–30% was obtained, considering both the total material removal volume and unit-angle material removal volume. Finally, a spherical machining verification experiment was conducted on an ultra-precision machining tool, and the experimental findings agreed well with the simulation results, demonstrating the reliability of the proposed model. The theoretical model of this study can provide a basis for optimal cutting tool inclination angle selection during complex surface milling.

Chip Formation and Orthogonal Cutting Optimisation of Unidirectional Carbon Fibre Composites.

This study presents a thorough experimental investigation utilising the design of experiments and analysis of variance (ANOVA) to examine the impact of machining process parameters on chip formation mechanisms, machining forces, workpiece surface integrity, and damage resulting from the orthogonal cutting of unidirectional CFRP. The study identified the mechanisms behind chip formation and found it to significantly impact the workpiece orientation of fibre and the tool's cutting angle, resulting in increased fibre bounceback at larger fibre orientation angles and when using smaller rake angle tools. Increasing the depth of cut and fibre orientation angle results in an increased damage depth, while using higher rake angles reduces it. An analytical model based on response surface analysis for predicting machining forces, damage, surface roughness, and bounceback was also developed. The ANOVA results indicate that fibre orientation is the most significant factor in machining CFRP, while cutting speed is insignificant. Increasing fibre orientation angle and depth leads to deeper damage, while larger tool rake angles reduce damage. Machining workpieces with 0° fibre orientation angle results in the least subsurface damage, and surface roughness is unaffected by the tool rake angle for fibre orientations between 0° to 90° but worsens for angles greater than 90°. Optimisation of cutting parameters was subsequently carried out to improve machined workpiece surface quality and reduce forces. The experimental results showed that negative rake angle and cutting at moderately low speeds (366 mm/min) are the optimal conditions for machining laminates with a fibre angle of θ = 45°. On the other hand, for composite materials with fibre angles of θ = 90° and θ = 135°, it is recommended to use a high positive rake angle and cutting speeds.

A force-insensitive impedance compensation method for giant magnetostriction ultrasonic cutting system of Nomex honeycomb composites

The high-quality machining of Nomex honeycomb composites is challenging due to its intrinsic brittleness. The rotary ultrasonic cutting performed on Giant magnetostriction ultrasonic system (GMUS) has been recognized as a superior method for the high-quality machining of Nomex honeycomb, owing to its capability to generate large-amplitude ultrasonic tool vibration. The stability of ultrasonic tool vibration plays a critical role in guaranteeing the acceptable surface quality of Nomex workpiece. However, the unique inhomogeneity of honeycomb induces time-varying cutting force, which can violate the stability of ultrasonic tool vibration using conventional compensation methods. In this study, a force-insensitive impedance compensation (FIC) method was proposed to improve the vibration stability of GMUS for honeycomb machining. A theoretical model which describes the vibration characteristics of GMUS was developed to calculate the optimum compensation impedance to adapt the time-varying cutting force. Experimental tests were conducted on Nomex honeycomb composite to evaluate the performance of proposed FIC method by inspecting the surface quality of machined workpiece. The experimental results demonstrated that the compensated ultrasonic cutting system showed an enhanced vibration stability during the machining of Nomex honeycomb composite. Compared with conventional compensation method, the honeycomb processed by GMUS with the FIC method showed much fewer cell collapses.

Evaluating surface quality by luminance and surface roughness

In computer numerical control (CNC) machining, ensuring the production of high-quality of machined surfaces is important alongside factors such as high production speed and precision. However, existing surface quality evaluation methods are inconclusive, being largely based on photographic or human visual inspection. Therefore, a method must be developed to quantify and evaluate the surface quality of machined parts, enabling the further study of high-quality machining conditions. Improvements in the surface quality of machined workpieces and identification of parts having low surface quality is expected to reduce the need for and improve the efficiency of hand polishing processes. Therefore, this study evaluated the surface quality of a machined surface by associating an index of luminance measured by a vision system with an index of surface roughness measured by a microscope. Furthermore, the luminance differences were imaged to visualize the surface quality. Different conditions of pick feed and feed amount were used, and the method of imaging them was studied. It was observed that low values of Lq/Lm (root mean square luminance/luminance mean) and Ldq (root mean square luminance difference) were reliable indices of high quality. The surface quality was visually evaluated, and the uneven machined surface was clearly identified by the obtained luminance difference images using a threshold value.

Optimization of CNC Turning Parameters Using Taguchi Method

The surface roughness quality of machining product plays important role when it contacted with other machine components. That quality depends on several parameters setting, such as material, cutting tool, cutting condition and operator skill. The aim of this study is to obtain the optimum setting of turning parameters by using Taguchi method. Three control factors: cutting speed, depth of cut, and feeding at three different levels are selected. A series CNC turning process on AISI 1045 material were performed using L9 (3)3 orthogonal array with cutting fluid. Insert carbide cutting tool is used in the experiment. In order to reveal the optimum machining parameter, smaller the better is quality characteristic selected for surface roughness examination of workpiece. Analysis of experiment results revealed that higher cutting speed, low feed, low depth of cut respectively, provides fine surface quality of machined workpiece. Moreover, feed f parameter was found most influence to the surface rougness quality with 53.73% contribution, cutting speed v provides 23.28% contribution, and depth of cut a provides 17.87% contribution. Confirmation experiment shows that level 3 of cutting speed, level 2 of cutting depth, and level 1 of feed deliver smoothest machined surface of Ra 0,46 µm.

Управляемые шпиндельные опоры как инструмент обеспечения качества обработки

The purpose of the work is to provide conditions for machined workpiece surface quality control based on the use of gas-magnetic supports in machine-tool systems (on example of the 3K227A internal grinding machine). To model the trajectory of tool and workpiece mutual movement the methods of nonlinear dynamics are used. The literature data on the problem are analyzed and experimental studies are carried out. Based on the considered issues of controlling the dynamic stability of technological systems under machining by means of contactless controlled gas-magnetic supports of spindle units, a scheme for adaptive control of the machine-tool system is proposed. It allows in many respects to eliminate external mechanical effects on the technological system, internal vibrations caused by drives and moving parts, as well as to compensate temperature deformations of the spindle unit frame and body. An adaptive control system based on gas-magnetic supports of the spindle assembly and the workpiece, as well as the control systems of the position of workpiece and tool (on example of 3K227A internal grinding machine) are demonstrated in action. The gas-magnetic support control system developed at Komsomolsk-na-Amure State Technical University makes it possible to set the position of the rotor axis with the accuracy of 0.1 microns. The study results obtained lead to the conclusion that the control of two adaptive links on the gas-magnetic supports, i.e., the spindle assembly of the tool and the spindle assembly of the workpiece, allows to achieve a rotation accuracy of up to 0.2 microns. The methods of nonlinear dynamics make it possible to construct an attractor (trajectory) of the tool tip movement in the real time, which provides a possibility to affect the input parameters of the machining process and thereby to control the output parameters. In addition to this, the control system of machine-tool system dynamic stability is applicable to other processing types as well, including edge cutting machining.

COMPLEXITY-BASED ANALYSIS OF THE INFLUENCE OF MACHINING PARAMETERS ON THE SURFACE FINISH OF DRILLED HOLES IN DRILLING OPERATION

Drilling is a famous and widely used machining operation to make holes in the workpiece. The size and surface quality of drilled hole are two factors that should be considered mainly. In this research, we examine the effect of different machining parameters and conditions on the surface quality of generated hole in drilling operation. For this purpose, we employ fractal theory and investigate how the variations of depth of cut and spindle speed affect the complexity of surface texture of drilled holes in wet and dry machining conditions. Based on the obtained results, the increment of depth of cut and spindle speed in case of wet and dry machining causes lower complexity on the generated surface from drilling. In addition, the generated surface from dry machining is more complex than the generated surface from wet machining. The obtained method in this research can be applied to other machining operations in order to investigate the effect of machining parameters and conditions on the surface quality of machined workpiece.

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.

Experimental study on correcting the contour error of a rotary surface machined by electrochemical mechanical machining

Effectively improving the precision and surface quality simultaneously is the goal of manufacturing technology. Due to the excellent surface quality of machined workpieces, electrochemical mechanical machining (ECMM) has been widely used as a polishing method for different components. Recent studies have found that ECMM can not only reduce surface roughness, but also improve precision to some extent. Under precision machining conditions, the roughness error value is close to the precision error value; therefore, leveling the roughness can improve the precision. To explore whether correcting the contour error of a rotary surface is caused by roughness improvement or the fundamental changes of its profile, orthogonal experiments were carried out to verify that electrochemical parameters had more influence on the precision than mechanical parameters. The machining current was the most important factor for accuracy. On this basis, an experiment was carried out under changing cathode coverage, and the results showed that component precision was affected by the cathode coverage on the workpiece surface. Specifically, the contour macro morphology exhibited a remarkable change with increasing cathode coverage, and this change was independent of roughness. This result demonstrated that under the same mechanical and electrochemical parameters, the contour error, which can be attributed to error homogenization, could be corrected by enlarging the influence area of the cathode on the workpiece surface. Therefore, ECMM can not only polish the part surfaces, but also fundamentally improve machining accuracy, showing promising application prospects in the trans-scale precision shaping of high-precision components.

Fractal-Based Analysis of the Relation Between Surface Finish and Machine Vibration in Milling Operation

Analysis of surface quality of machined workpiece is an important issue in machining of materials. For this purpose, scientists analyze how the texture of machined surface changes due to different conditions. Machine vibration is one of the factors that highly affects the surface quality of machined surface. In this research, we analyze the relation between machine vibration and surface quality of machined workpiece. For this purpose, we employ fractal theory and analyze how the complex structure of machined surface changes with the complex structure of machine vibration signal in case of variations of machining parameters, namely, depth of cut, feed rate and spindle speed, in milling operation. Based on the results, variations of surface quality of machined workpiece are related with the variations of complexity of machine vibration signal. The method of analysis employed in this research can be applied to other machining operations in order to find the relation between machine vibration and surface quality of machined workpiece.

DECODING OF THE RELATION BETWEEN FRACTAL STRUCTURE OF CUTTING FORCE AND SURFACE ROUGHNESS OF MACHINED WORKPIECE IN END MILLING OPERATION

Analysis of the surface quality of workpiece is one of the major works in machining operations. Variations of cutting force is an important factor that highly affects the quality of machined workpiece during operation. Therefore, investigating about the variations of cutting forces is very important in machining operation. In this paper, we employ fractal analysis in order to investigate the relation between complex structure of cutting force and surface roughness of machined surface in end milling operation. We run the machining operation in different conditions in which cutting depths, type of cutting tool (serrated versus square end mills) and machining conditions (wet and dry machining) change. Based on the obtained results, we observed the relation between complexity of cutting force and surface roughness of generated surface of machined workpiece due to engagement with the flute surface of end mill, in case of using square end mill in dry machining condition, and also in case of using serrated end mill in wet machining condition. The fractal approach that was employed in this research can be potentially examined in case of other machining operations in order to investigate the possible relation between complex structure of cutting force and surface quality of machined workpiece.

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.

ANALYSIS OF THE CORRELATION BETWEEN FRACTAL STRUCTURE OF CUTTING FORCE SIGNAL AND SURFACE ROUGHNESS OF MACHINED WORKPIECE IN END MILLING OPERATION

Analysis of the machined surface is one of the major issues in machining operations. On the other hand, investigating about the variations of cutting forces in machining operation has great importance. Since variations of cutting forces affect the surface quality of machined workpiece, therefore, analysis of the correlation between cutting forces and surface roughness of machined workpiece is very important. In this paper, we employ fractal analysis in order to investigate about the complex structure of cutting forces and relate them to the surface quality of machined workpiece. The experiments have been conducted in different conditions that were selected based on cutting depths, type of cutting tool (serrated versus. square end mills) and machining conditions (wet and dry machining). The result of analysis showed that among all comparisons, we could only see the correlation between complex structure of cutting force and the surface roughness of machined workpiece in case of using serrated end mill in wet machining condition. The employed methodology in this research can be widely applied to other types of machining operations to analyze the effect of variations of different parameters on variability of cutting forces and surface roughness of machined workpiece and then investigate about their correlation.

Performance of Microtextured Tools Fabricated by Inductively Coupled Plasma Etching in Dry Cutting Tests on Medium Carbon Steel Workpieces

Microtextures were successfully fabricated on the rake face of the cemented carbide (WC/TiC/Co) tools through inductively coupled plasma etching technology. Two types of microtextured tools were designed and fabricated. Their performance in cutting the AISI 1045 medium carbon steel was tested and compared to that of conventional non-textured tools. The comparison involved cutting forces, cutting temperature, friction coefficient, tool wear, chip adhesion, and machined workpiece surface roughness. The results show that microtextures on the rake face of the cutting tool can make the cutting process more stable than a conventional non-textured tool, and different textures may be suitable for different ranges of the cutting speed. In the latter range 100–200 m/min, microtextures significantly reduce the cutting force, cutting temperature, friction coefficient at the tool–chip interface, while the anti-adhesion property of textured tools and the surface quality of machined workpieces attain their maximal values. The effectiveness of textures is shown to be affected by chip adhesion and blockage resulting from derivative cutting, which appears at high cutting speeds. Moreover, the violation of the structural integrity of textures and their damage can strongly deteriorate the cutting process at low cutting speeds.

Supervision controller for real-time surface quality assurance in CNC machining using artificial intelligence

A major challenge for Computer Numerical Control (CNC) machining is how to manufacture high-quality workpieces effectively. Consequences of poor surface quality incur re-processing and higher wastes generating negative impacts on production costs and profitability. The complex relationships between surface quality and machining parameters could overwhelm machinists’ capabilities to correctly select machining parameters to produce satisfied quality of machined workpieces. This paper presents a novel approach of designing an intelligent supervision controller for real-time adjustments on feed rate and spindle speed to achieve desired surface quality of machined workpieces. The controller is an innovative model-based closed-loop system, consisting of a surface roughness prediction model and a multi-variable controller, to ensure real-time improvements on surface quality during machining processes. A case study based on milling processes for BS EN24T steel alloy has been used for testing and validating the approach. Simulation results show that the controller significantly reduced the difference between required and predicted surface roughness from 3.6 μm (based on planned parameters) to 0.12 μm (after the supervision controller adjustments). The results demonstrate that the proposed approach can effectively support high-quality machining processes.

A prediction model for titanium alloy surface roughness when milling with micro-textured ball-end cutters at different workpiece inclination angles

Studies have found that milling with an inclined plane when using ball-end milling cutters can reduce heating of the cutting tool. It has also been found that micro-textures on the rake face can play a role in the reduction of friction and wear. Taking these things together, milling titanium alloy with micro-textured ball-end milling cutters with workpieces at an inclined angle can have a significant influence on tool wear and the surface quality of machined workpieces. We have therefore looked at the factors affecting the quality of machined surfaces using an orthogonal test and, in particular, the effect of different micro-texture parameters and different workpiece inclination angles. Through means of an extreme difference analysis, the primary and secondary relationship between micro-texture parameters, workpiece inclination angles, and surface roughness is assessed. The analysis focuses in particular on the distance between micro-pits, micro-pit diameter, the workpiece inclination angle, the distance between the first row of micro-pits and the cutter edge, and the depth of the micro pits. On the basis of the analysis, a model that can predict surface roughness is established that provides a means of optimizing micro-textured cutter design and machining inclination angles when milling titanium alloy.

Effect of texture parameters on cutting performance of flank-faced textured carbide tools in dry cutting of green Al2O3 ceramics

Tool wear and surface quality are the most important problems in green ceramic processing. This paper fabricated textures with different texture parameters on the flank face of carbide tools by femtosecond laser, to enhance the wear resistance of carbide tools and surface quality of machined compacts. The wear resistance of textured tools and quality of machined surface were evaluated in cutting tests of the green Al2O3 ceramics with these different flank-faced textured tools. Results showed that better flank wear resistance of textured tools and better quality of machined surfaces could be obtained by flank-faced textured tools than that by conventional tool (WT-0). The parameters of flank-faced textures had a significant effect on the flank wear resistance of textured tools and surface quality of machined workpieces. To achieve best wear resistance of cutting tool and surface quality of workpieces within the experiment parameters, the best parameters of the textures were chosen that width of the texture groove was 75 µm, spacing of texture groove was 100 µm, and distance of texture groove to main cutting edge was 75 µm. “Derivative cutting” to the hard inclusions in the surface of workpieces was happened at the textured grooves’ lower edge. It contributed to enhancement of wear resistance and the surface quality in a certain parameter of texture grooves.

Investigation on notch wear mechanism in finish turning pure iron material with uncoated carbide tools under different cooling/lubrication conditions

Notch wear is the main failure mode in finish turning pure iron material, which determines the tool life and has an important effect on machined workpiece surface quality. In this paper, in order to reduce notch wear in finish turning pure iron material, the evolutions and mechanisms of notch wear on cutting tool edge are studied with different cutting parameters and four kinds of cooling/lubrication conditions, such as wet cutting, dry cutting, hand operation to brush rapeseed oil on unmachined workpiece surface, and minimum quantity lubrication (MQL). The results show that two notch wear formations are observed at the major cutting edge and the minor cutting edge on flank face as well as two obvious notch wears on rake face. The main wear mechanisms of notch wear are the seizure/pullout, diffusion wear, and oxidation wear. Cooling/lubrication conditions have an important effect on major and minor notch wear. The major and minor notch wear under wet cutting with different cutting speeds have the largest wear rates, following under dry cutting and rapeseed oil lubrication conditions. MQL condition is suitable for the finish turning of pure iron materials. Therefore, in order to decrease notch wear, in finish turning pure iron material, tool cooling must be minimized and tool lubrication must be favored.

Analysis of Path Distribution in Lapping and Polishing with Single Fixed Abrasive

The path distribution can directly affect the machined workpiece surface quality in lapping and polishing, such as planeness, roughness, etc. In present paper, the influence of rotate speed ratio (RSR) and abrasive position on path distribution was analyzed with a single fixed abrasive. The results show that the RSR and abrasive position has heavy influence on the path distribution. The path distribution with decimal RSR is more intensive and complicate than that with integer RSR, especially complex decimal RSR, and it can be also affected by the abrasive radial and circumferential position, but the shape of path is not changed with different abrasive circumferential position which only affects the initial phase angle of path.