Workpiece Rotational Speed Research Articles

Modeling of Surface Waviness in Abrasive Waterjet Offset-Mode Turning

In this paper, surface waviness produced by turning aluminum parts with abrasive waterjet has been studied regarding changes in some process parameters. Effect of five major parameters such as water pressure, cutting head traverse speed, abrasive mass flow rate, workpiece rotational speed and depth of cut have been investigated using analysis of variances. Second order regression model presented forwaviness.The validity of the model wasconfirmed bycomparing with experimental data. It found thatabrasive mass flow rate, cutting head traverse speed and DOC are the most influencing parameters while water pressure and workpiece rotational speed show lesser effectiveness.

Research on the Influence of NС Quick-Point Grinding Parameters to Complex Rotator Surface Roughness

It studies the influence of linear speed of grinding wheel and rotational speed of workpiece to complex rotator surface roughness. Using self-designed NC quick-point grinding machine do the grinding test at different linear speeds of grinding wheel and different rotational speeds of workpiece, gained the relationship curve between the linear speed of grinding wheel, rotational speed of workpiece and complex rotator surface roughness. The test results show that using quick-point grinding technology can grind multiple external cylindrical and cone-shaped surfaces by only one time fixing, it can get 0.025um surface roughness in a reasonable condition of the grinding parameters. During point grinding process, higher wheel speed gets better surface roughness, higher workpiece shaft speed gets worse surface roughness.

The study of dry grinding of steel cams using cubic boron nirtride tools

Experimental studies that simulate grinding of hardened alloyed steel cams have demonstrated that these workpieces can be machined with a minimum work surface heating by using highly porous cubic boron nitride wheels with the oil mist cooling or without cooling. It has been found out that for minimizing the thermodynamic stress level in the dry grinding mode it is advisable to preset machining conditions with maximum possible depth of cut and minimum workpiece rotational speed.

Study on magnetorheological nano-polishing using low-frequency alternating magnetic field

With the development of electronics and optical industry, the high-efficiency ultra-precision polishing technologies of flat and curved surfaces are in high demand. The traditional magnetorheological polishing technology, using flexible polishing head, has the disadvantages of low polishing efficiency and small processing area. In this study, a novel tray-type magnetorheological polishing process using low-frequency alternating magnetic field excitation was developed to improve the efficiency of magnetorheological polishing for large surfaces and to make polishing magnetorheological cluster generate a cyclical fluctuation up and down, and then improve the cross-cutting effects of abrasives. With the developed excitation system, a large bowl-shaped varying magnetic field was generated in the working area, and the effects of current frequency, working gap, trough rotation speed, and workpiece rotation speed on the improvement rate of surface roughness and material removal rate were systematically investigated. A series of experiments were conducted on K9 glass specimens to verify the polishing performance. Experimental results show that the surface roughness of K9 glass was improved from 567.08 to 9.63 nm in 120 min.

Investigation of the Effects of Machining Parameters on Material Removal Rate in Abrasive Waterjet Turning

The effects of the main operational machining parameters on the material removal rate (MRR) in abrasive waterjet turning (AWJT) are presented in this paper using a statistical approach. The five most common machining parameters such as water pressure, abrasive mass flow rate, cutting head traverse speed, workpiece rotational speed, and depth of cut have been put into a five-level central composite rotatable experimental design (CCRD). The main effects of parameters and the interaction among them were analyzed by means of the analysis of variance (ANOVA) and the response surfaces for MRR were obtained fitting a second-order polynomial function. It has been found that depth of cut and cutting head traverse speed are the most influential parameters, whereas the rotational speed is insignificant. In addition, the investigations show that interactions between traverse speed and pressure, abrasive mass flow rate and depth of cut, and pressure and depth of cut are significant on MRR. This result advances the AWJT state of the art. A complete model discussion has been reported drawing interesting considerations on the AWJT process characterising phenomena, where parameters interactions play a fundamental role.

Parametric Study and Optimization of Nd: YAG Laser Micro-Turning Process of Different Grade of Alumina Ceramics Based on Taguchi Methodology

The present paper addresses an investigation on the effect of process parameters during Nd:YAG laser micro-turning operation of different grade of alumina (Al2O3) ceramic materials. Considering different levels of various process parameters i.e. laser beam average power, pulse frequency, workpiece rotational speed and Y feed rate, Taguchi method based experimental design has been used to construct the set of experiments. The same set of experiments has been utilized to machine 10 mm diameter cylindrical workpiece made of different grades of Alumina ceramics i.e. K60 and K80. Surface roughness (Ra) and micro-turning depth deviation were considered as the process characteristics. Analysis of variance (ANOVA) test was performed for each grade of alumina ceramic to find out the significant process parameters during laser micro-turning process. The optimum process parameters settings for individual responses were obtained by analyzing the signal-to-noise (S/N) ratio. Mathematical models, which correlate the response and process variables, have been developed for all the grades of ceramics. Multi-objective optimization i.e. simultaneous minimization of surface roughness (Ra) and micro-turning depth deviation has been done through combined approach of Taguchi methodology and Grey Relational Analysis.

Experimental Investigations into Electrochemical Magnetic Abrasive Machining of Cylindrical Shaped Nonmagnetic Stainless Steel Workpiece

This work presents the machining performance of cylindrical electrochemical magnetic abrasive machining (C-EMAM) for high efficiency machining of cylindrical surfaces. Experiments were carried out on self-developed C-EMAM setup to explore the performance of the process during machining of nonmagnetic stainless steel cylindrical workpiece using unbonded magnetic abrasive particles. The performance of this process is evaluated in terms of material removal (MR) and surface roughness (Ra). The effect of various process variables viz. electrolytic current, magnetic flux density, and rotational speed of workpiece on process performance were investigated. It is observed that the electrochemical process has major contribution in MR, whereas magnetic abrasive machining helps in reduction in Ra due to higher abrasion-assisted passivation particularly at peaks of surface profile. In the C-EMAM process, MR is observed to be increased by 500% to 1,800% as compared to the magnetic abrasive machining (MAM) process. At constant magnetic flux density, with 200% increase in electrolytic current, the MR increases by 172%, whereas Ra reduces by 50% with respect to 0.5 A current. This process has higher machining efficiency particularly at high value of electrolytic current and high rotational speed.

A Magnetic-Assistance System as a Super Finishing Following Turning Machining

A design system using a magnetic force with high efficiency to assist discharging dregs out of the electrode gap during the electrochemical finishing on the surface finish process that follows turning machining process is investigated in the current study. Through the equipment attachment, magnetic-assistance during electrochemical finishing can follow the turning process on the same machine. This process can be used for various turning operations. Among the factors affecting electrochemical finishing, the magnetic-assistance is primarily discussed. The experimental parameters are magnetic strength, distance between the two magnets, current rating, on/off period of pulsed current, feed rate of workpiece, and rotational speed of workpiece. A higher current rating with magnetic-assistance reduces the finishing time and avoids the difficulty of dreg discharge. Providing a large magnetic field intensity or using a small distance between the two magnets produces a larger magnetic force and discharge ability and better finishing. A large rotational speed of the workpiece and electrode produces better finishing. Pulsed direct current can slightly promote the effect of electrochemical finishing, but the current rating needs to be increased. The magnetic-assistance during the electrochemical finishing process makes a great contribution in a short time by making the surface of the workpiece smooth and bright.

Cylindrical Electrochemical Magnetic Abrasive Machining of AISI-304 Stainless Steel

This work presents the machining performance of cylindrical electrochemical magnetic abrasive machining for high efficiency machining of cylindrical surfaces. Experiments were conducted on self-developed process setup for machining of AISI-304 stainless steel workpiece based on central composite rotatable design technique of response surface methodology. The effect of different process variables (viz. workpiece rotational speed, current to electromagnet, electrolytic current and frequency of vibration) on output responses (viz. material removal [MR], surface roughness [Ra]) is investigated. Analysis of the model shows that the workpiece rotational speed and electrolytic current have a significant influence on MR and Ra. Increasing both the workpiece rotational speed and electrolytic current leads to significant increase in MR and simultaneous reduction in Ra due to synergistic effect of abrasion-assisted passivation and passivation-assisted abrasion.

A study of electrochemical magnetic abrasive machining process

This paper presents the study of hybrid machining process consisting of electrochemical dissolution and magnetic abrasive machining. Experiments were conducted on self-developed cylindrical electrochemical magnetic abrasive machining (C-EMAM) setup to explore the finishing results of the process on non-magnetic stainless steel using unbonded magnetic abrasives. The effect of electrolytic current, magnetic flux density and rotational speed of workpiece on material removal and surface roughness were investigated. It was observed that the rotational speed of the workpiece, magnetic flux density and electrolytic current should be properly fitted to achieve passivation-abrasion synergism. The problems associated with the process, which reduces the performance are also discussed.

Suppressing Chatter in a Plunge Grinding Process: Application of Variable Rotational Speed of Workpiece

This paper investigates the regenerative chatter in a plunge grinding process. The effect of the contact force on the onset of chatter vibration is clarified by a proposed continuation algorithm, and the boundary for the chatter-free region in which the grinding process is stable is obtained. By varying the rotational speed of the workpiece continuously, the chatter vibration with the values of the system parameters being near the boundary is suppressed, namely, the chatter-free region is expanded by this spindle speed variation control strategy.

Precision Grinding Characteristics and Process Optimization on YG3 Cemented Carbide

Precision grinding experiment and process optimization of YG3 cemented carbide materials was conducted with various grinding parameters using resin-bonded diamond grinding wheel. Different rotation speed of workpiece, feed rate and grinding depth were chozen in precision cross grinding. Surface roughness was measured for studying the removal mode and grinding charateristics. A set of ideal grinding parameters of YG3 cemented carbide were obtained by changing the process parameters. The research result has guiding significance for reducing the wheel wear and processing costs, improving grinding quality and efficiency while precision grinding hard and brittle materials.

Experimental investigation and multi-objective optimization of Nd:YAG laser micro-turning process of alumina ceramic using orthogonal array and grey relational analysis

The present paper addresses an experimental investigation on the effect of process parameters during Nd:YAG laser micro-turning operation of 99% of alumina (Al2O3) ceramic materials. Taguchi methodology based experimental design was adopted for carrying out experimentations. The process parameters considered during machining are laser beam average power, pulse frequency, workpiece rotational speed and Y feed rate. Surface roughness (Ra) and micro-turning depth deviation were considered as the performance criteria for the present experimentation. Analysis of Variance (ANOVA) was performed to find out the significant process parameters during laser micro-turning process. The optimum process parametric settings were obtained by analyzing the signal-to-noise (S/N) ratio values. Experiments on optimal process parametric settings of the responses have been carried out and overall error percentage in S/N ratio calculated is 3.59%. The mathematical model for each of the responses has been developed to predict the mentioned response criteria. Validity of the models have been checked through experiments and the overall error percentages of surface roughness (Ra) and micro-turning depth deviation for validation experiments are 2.83 and 2.96%, respectively. Further experiments have been conducted to study and analyse of the most contributing parameters on respective process criteria.

Analyzing Effect of Interactions of Process Parameters on Surface Finish of SUS304 Steel Roller Using RSM Technique

Finishing of cylindrical workpieces of SUS304 steel has been done using loosely bonded diamond based magnetic abrasives prepared by homogeneous mixing of magnetic powder (Fe powder of 300 mesh size (51.4μm)), abrasive powder (Diamond particles of 200 mesh size (41μm)), and lubricant. A central composite design involving four variables has been employed using RSM techniques to establish a mathematical model between parameters and response (percent improvement in surface finish), a series of experiments have been conducted using in-house fabricated setup. It has been found that magnetic flux density, quantity of magnetic abrasives, rotational speed of workpiece and percentage of abrasives in magnetic abrasives has significant effect on PISF. The maximum percentage improvement in surface finish was found to be 81% (0.04 μm Ra) at 1.0 Tesla of magnetic flux density, 40 mg of magnetic abrasives, 800 rpm as rotational speed of workpiece and 40% of abrasive. Scanning Electron Microscope (SEM) photographs shows that the surface generated by turning on lathe consists of deep scratches. The peaks have been sheared off to much smaller heights by MAF resulting in improved surface finish, but fine scratching marks produced by MAF appear on the surface.

Predictive model and process parameters optimization of Nd:YAG laser micro-turning of ceramics

The present work highlights laser micro-turning operation of 10-mm diameter cylindrical-shaped alumina (Al2O3) ceramic using pulsed Nd:YAG laser. The paper also addresses development of mathematical models for correlating the various micro-machining parameters such as laser beam average power, pulse frequency, workpiece rotational speed, assist air pressure, and Y feed rate with the response criteria such as surface roughness and deviation in turned depth for achieving desired surface quality as well as dimensional accuracy during micro-turning operation using Nd:YAG laser system. Response surface methodology-based design of experiments has been adopted for the experimentation. This investigation also highlights the various test results that confirm the validity and correctiveness of the developed mathematical models through analysis of variance test. The test results were analyzed through various response surface plots to study the effect of the process parameters on the aforementioned responses. The results of validation experimentation show a good agreement for the developed empirical models. Sensitivity analyses of the developed models have been done to find out the variation in the output with respect to variations in the significant input process parameters. Moreover, multi-performance optimization has been done to find out the optimal parametric setting for achieving the desired process performances. Analysis also has been made based on scanning electron microscopy micrographs of the laser micro-turned surface achieved during machining at multi-criteria optimization setting.

Design an Apparatus for Obtaining to High Precision Surface of Miniature Parts Based on Magnetized Abrasive Grains Finishing Process

Obtaining to high quality surfaces of industrial parts is an important manner for manufacturing involves. Different finishing process are capable to providing the require surface roughness in most cases, considering that, in some special parts, depending on shape, material and dimension of parts, the prevalent methods are limited, especially in finishing of sculptural and curvilinear surfaces. In this research, a new applied apparatus is represented based on magnetized abrasive grains finishing process. In this way, abrasive grains gathering around a rotational cylindrical tool thanks to a permanent magnetic field and work-piece, which usually is a formed thin metal sheet, located on a rotary table. Therefore, coinciding of those motions providing the require machining forces for finishing of surface without any physical contact between tool and work-piece. Presented process may carry out dry and wet in case of changing the main machining parameters such as: material and size of abrasive grains, tool and work-piece surface gap distance, tool and/or table rotational speed (r.p.m) and work-piece material. The recommended process has remarkable advantages such as: non-contact surface finishing, high finishing of non-flat surfaces, no need to clamping for work-piece because of low machining forces, responsibility for finishing of a wide range of materials except magnetizable parts, low machining costs and easy set up. This method has a lot of applications in production of optical lens, orthopedic prosthetic components and jewellery. For approve of the designed apparatus advantages, relative to other existed MR fluid machining system, some samples of very thin complex formed sheet have been successfully polished.

Determination of efficient superfinishing conditions for mirror surface finishing of titanium

To determine mirror surface finishing conditions and efficient and economical superfinishing conditions for pure titanium and titanium alloys, an abrasive film is used when superfinishing is performed under varying conditions. These conditions include the workpiece rotation speed, the oscillation speed, the contact pressure of the roller, the hardness of the roller, and the type of abrasive film. The superfinishing device is applied to polishing a thin and long cylindrical bar. A micro-finishing film and a lapping film were used as abrasive films. Al2O3 grains or SiC grains were used as abrasives. The surface roughness of a polished workpiece was measured using a stylus-type surface-roughness measuring instrument. As a result, the conditions to improve the polishing surface efficiently include high values for the workpiece rotation speed, oscillation speed and contact pressure. The roller hardness has no effect on the efficient polishing conditions. The mirror finish of a surface can be created using lapping film of 3 μm with Al2O3 grains after polishing to a steady surface roughness under the efficient polishing conditions.

Optimisation of Nd:YAG laser micro-turning process using response surface methodology

The present paper investigates the laser micro–turning operation on cylindrical aluminium oxide (Al2O3) ceramic to study the influence of different process parameters namely, laser average power, pulse frequency, workpiece rotational speed, assist air pressure and Y feed rate on surface roughness (Ra and Rt) and micro–turning depth deviation. The mathematical models for the responses have been developed based on response surface methodology (RSM). Through different surface plots, analyses have been made to study the influences of process parameters on responses. The adequacy of the developed models has been tested through analysis of variance (ANOVA). To investigate into the variation in the output for small variations in significant process parameters, sensitivity analyses (SA) have been done of the models developed for each response. Multi–objective optimisation has also been performed for searching out the optimal parametric condition for achieving minimum surface roughness and minimum depth deviation during laser micro–turning process.

Experimental investigations into cylindrical electro-chemical magnetic abrasive machining of AISI-420 magnetic stainless steel

Cylindrical electro-chemical magnetic abrasive machining (C-EMAM) is an advanced abrasion-based hybrid machining process used for efficient finishing of cylindrical surfaces made of difficult-to-machine electrically conducting materials. In this work, experiments were performed on self-developed C-EMAM process setup to investigate the effects of electrolytic current, current to electromagnet, workpiece rotational speed and frequency of vibration on performance of the process during machining of magnetic stainless steel (AISI-420) using unbonded magnetic abrasives. The performance of the process is evaluated in terms of material removal and surface roughness. It is observed that for magnetic steel, magnetic abrasion has significant contribution in material removal, whereas electro-chemical dissolution helps rapid reduction in surface roughness due to abrasion passivation-synergism at peaks of surface profile. Workpiece speed and current to electromagnet have greater effect on synergy of material removal.

B25 テクスチヤ表面の高能率切削(OS6 切削加工(1))

simultaneous controlled cutting is presented to fabricate micro-scale textures on surfaces at high machining rates. The surface texture is machined with rotations of the workpiece and the tool on a turning center. The centers of the workpiece rotation and the tool holder rotation are located eccentrically in the process. The periodical circular textures are controlled by 3 parameters: the distance between the centers of the workpiece rotation and the tool holder rotation; the rotation radius of the cutting tool on the tool holder; and the ratio of the tool rotation speed to the workpiece rotation speed. Some surface textures are machined with changing the cutting parameters in the experiments. The cutting force, then, is measured by piezoelectric dynamometers in cutting of a surface texture on an aluminum plate.