Workpiece Diameter Research Articles

Evaluating Influences of Input Parameters on Surface Roughness in Sinking EDM Cylindrical Shaped Parts

The input parameters in the process of sinking Electrical Discharge Machining (EDM) are the essential enabling factors that need to be determined. In the present work, the influences of the EDM input parameters containing pulse on time (Ton), pulse off time (Toff), discharge current (IP), Server voltage (SV), work-piece diameter (dw) on the surface roughness (SR) in sinking EDM cylindrical shaped part of 9CrSi material were investigated. Taguchi technique and analysis of variance (ANOVA) have been used to identify the weight of EDM factors on SR. The results show that the impact level of Ton, Toff, IP, SP, and dware 65.55%, 8.66%, 19.17%, 3.14%, and 0.76%, respectively. By analyzing the experimental results, optimum input parameters with the Tonof 6 ms, Toffof 30 ms, IP of 9A, SP of 3V, and dwof 10mm have been determined, that allow getting the best surface roughness.

Technical and Economic Description of the Research on a Measuring Device for Continuous Measurement of the Diameter and Vibration of the Workpiece during the Machining Process

This article is devoted to the economic and technical aspects of the research on continuous noncontact measurement of the workpiece diameter during the manufacturing operation using a suitably selected and designed sensor. In order to achieve this main goal, it was necessary to meet these partial goals. We develop and describe a method of accurate continuous technical measurement of the workpiece diameter during the machining process. We propose a principle of continuous technical measurement of workpiece diameter, design a scanning method based on this principle, and verify the developed equipment on a specific case of technical measurement. At the same time, the development includes the expansion of the use for continuous noncontact measurement of workpiece vibrations. Based on test measurements, an optical sensor was selected, the analysis of which is presented in a part of the article. The introduction of this article provides a simple view of the need for continuous measurement of the workpiece diameter. The second chapter presents the current state of the problem. The third chapter is devoted to the theoretical analysis and description of practical implementations of the solution. The conclusion, as it could be expected, includes evaluation of the results.

Analysis of Effects of Machining Parameters on Cutting Force Components in Turning AISI 201 Stainless Steel Using Cemented Carbide Cutting Tool Insert

Abstract The effectiveness of the finished component in turning process is highly reliant on the parameters related to the workpiece and cutting tool. This paper aims to assess the impact of machining parameters on tangential, radial and axial forces while turning AISI 201 stainless steel using cemented carbide tool insert. Process parameters such as spindle speed, feed, depth of cut, and workpiece diameter were used. Four-factors and four-level L16 Taguchi Design of Experiments were employed. In addition, the Analysis of Variance (ANOVA) was used to explore the effects of process parameters and their impact on interactions. After that, an attempt was made to generate prediction models by establishing a regression equation for the cutting forces. Predicted and measured values were plotted in the graphs and comparisons were shown. Finally, the interaction effects between the cutting forces and machining parameters were analyzed as well.

Micro-texturing on flat and cylindrical surfaces using electric discharge micromachining

The present work discusses micro-texturing on flat and cylindrical surfaces using the electric-discharge micromachining (EDMM) process. The arrays of micro-dimples are generated on flat Ti-6Al-4V surfaces using a block–electric discharge grinding (block-EDG)–fabricated microtools of an average diameter of 148 µm and 105 µm. Large-area surface texturing on flat Ti-6Al-4V and aluminium surfaces are performed to analyse the variation in water contact angle with varying depths of dimples. Adopting the electric discharge–milling (ED-milling) strategy, micro-pillars of dimensions 242 µm × 166 µm × 50 µm are machined on flat Ti-6Al-4V surfaces. The EDMM process for non-flat surfaces, such as curved (internal and external), spherical and freeform surfaces, is receiving attention in various applications. Machining of the aforementioned surfaces using the EDMM process appears to be problematic, due to the continuous change in curvature, which results in the subsequent spark gap variation. In the present work, processing of cylindrical surfaces for micro-features generation, such as micro-dimple arrays, has been attempted. Arrays of micro-dimples are machined on copper and Ti-6Al-4V cylindrical surfaces. A precise indexing setup is fabricated to hold and index the workpiece at the desired angular positions. Unlike machining on flat surfaces, the relative dimensions of the tool and the workpiece’s curvature result in non-uniform wear at the tool’s end cross-section. Owing to this non-uniform wear of tool electrode caused by the curvature effect of the workpiece, the formation of a microscopic bump/spike is observed on the dimple’s bottom. The depth of the dimple up to which the entire bottom surface of the tool is not exposed to the sparks is defined as its critical depth. For a combination of a tool and a workpiece of diameters 500 µm and 5 mm, respectively, the critical depth of the dimple is found to be 12.53 µm. However, the critical depth increases with a decrease in workpiece diameter, provided the diameter of the tool is constant.

Determining a contact spot in the orbital burnishing deformation

The influence of the orbital burnishing main parameters on the configuration, size and area of the plastic contact spot during cylindrical parts processing is studied using SolidWorks software. The computer modeling results show that indent size and contact area are mainly affected by the working tool inclination angle, orbital rotation radius and the penetration depth, while the working tool radius and the workpiece diameter are of less significance.

Fine-finishing of stepped cylindrical workpiece using magnetorheological finishing process

A various stepped cylindrical workpieces are commonly known for their functionality in different industrial components such as hydraulic or pneumatic actuators, plungers, etc. However, fine-finishing of stepped cylindrical workpiece (made of softer materials) is difficult by grinding operation because of its rigid tool structure. This tool structure is made by the rigid bonding of abrasive particles to a comman wheel. When this rigid tool approaches the workpiece surface, it results with different surface defects such as pits, scratches, grooves, cavity, etc. To overcome such circumstances, magnetorheological (MR) processes can be used. These processes use MR polishing fluid for fine-finishing of different materials ranging from soft to the harder type. In the present work, the MR finishing process is used for finishing of the external surfaces of stepped cylindrical workpiece. The MR finishing tool is developed in such a way that it is flexible in accordance with the diameter of cylindrical workpiece. In this tool structure, the permanent magnets (made up of neodymium NdFe35) have been used for retaining the MR polishing fluid on its surface. Experiments have been conducted on the aluminium stepped workpiece in order to check the practicability of the present developed tool. The results revealed that a fine-finishing of stepped cylindrical workpiece with a surface roughness R a value as 62 nm is achieved on aluminium workpiece. Also, the mechanism of material removal involved during the finishing process has been analyzed mathematically. Removal of material from the external surface of single step of aluminium workpiece has been confirmed mathematically with the help of the present developed MR finishing tool.

Thermo-mechanical aspects of cutting forces and tool wear in the laser-assisted turning of Ti-6Al-4V titanium alloy using AlTiN coated cutting tools

Machining of hard-to-cut materials with conventional processes is still considered as a challenge, as the special properties of these materials often lead to rapid tool wear and reduced surface integrity. For that reason, it is preferable to combine conventional machining processes with other technologies in order to overcome the problems of machining these materials. In the present work, laser-assisted turning experiments on a Ti-6Al-4V workpiece were conducted using AlTiN coated cutting tools in order to investigate the effect of laser heating on cutting forces, cutting temperature, tool wear and microstructure alterations. Two series of experiments were performed under varying cutting speed, laser spot diameter and workpiece diameter values; the first series involved only laser heating of the workpiece and the second both laser heating and cutting. The findings revealed the effect of process parameters on cutting forces and temperature determining the importance of workpiece diameter size, indicated the formation of martensite phase at the top of the heat-affected zone of the workpiece and also showed that high temperatures can lead to intensive tool wear, instead of having a beneficial effect for the cutting tool. Finally, finite element (FE) simulations were carried out in order to study the time evolution of the temperature field and calculate the heating and cooling rates during the process. From the FE results, relatively high heating and cooling rates were observed for smaller workpiece diameters and lower cutting speed, whereas the high magnitude of these rates justified the creation of the martensite phase through a diffusionless transformation.

Intelligent Hough Transform With Jaya to Detect the Diameter of Red-Hot Circular Workpiece

Diameter detection plays an important role in the production of circular workpieces. It is very difficult to obtain the accurate measurement of diameter when the circular workpiece is red-hot because of the existence of lots of noise. Although Hough transform (HT) has many advantages for diameter detection of circular workpieces, it has still suffered from some serious problems, which include the requirements of a large amount of computation and memory occupancy. To address these problems, we propose an intelligent Hough transform method with Jaya (IHTJ). The key points are as follows. We analyze the problem of diameter detection for red-hot circular workpieces, which is essentially the problem of ellipse fitting. Then the problem of ellipse fitting with HT is converted into searching optimal solution in parameter space, and we construct the fitness function based on the principle of ellipse fitting with HT. In order to fit the ellipse accurately and rapidly, we introduce Jaya to search the optimal ellipse parameters in parameter space at last, and the computation burden and memory occupancy of HT are greatly reduced. Compared with direct least-square (DLS), randomized Hough transform (RHT) and random sample consistency (RANSAC), IHTJ can fit the ellipse rapidly while the advantages of strong robustness and high accuracy of HT are retained. Some simulations and practical experiments are carried out to verify the effectiveness of IHTJ.

Experimental Research on Milling Temperature of New Cold Saw Blade Milling Cutter

Based on the orthogonal test method and comparative study, the effects of workpiece material, workpiece diameter, milling cutter rotational speed and feed per tooth on milling temperature are investigated when cutting metal bars with new cold saw blade milling cutter. Then this paper reveals the change rule of new cold saw blade milling cutter milling temperature and the essential difference from the traditional hot saw blade milling cutter. Construction of sawing metal bar experiment system at production site, four-factor and three-level orthogonal test method is used to cut 45 steel, 40Cr and Q235B metal materials. The influence curves of workpiece material, workpiece diameter, milling cutter rotational speed and feed per tooth on milling temperature are obtained. By normalizing the experimental data, this paper uses the multiple linear regression method to fit the mathematical model of milling temperature. According to simulation analysis and experimental research, the milling temperature change rule of new cold saw blade milling cutter is obtained. Compared with the traditional hot saw blade milling cutter, the results show that under the same or similar conditions, the highest milling temperature center of new cold saw blade milling cutter is located at the bottom of the chip at a certain distance from the tip and the interface of the corresponding cutting layer adjacent to the bottom layer of the chip. The maximum milling temperature is around 300 °C, which is about 175 °C lower than the maximum milling temperature of traditional hot saw blade milling cutter. Further, it demonstrates that most of the heat generated by cold sawing is discharged from the cutting area along with chips, which keeps the milling cutter and workpiece at a relatively low temperature.

Problems of forming stepped axles and shafts in a 3-roller skew rolling mill

The paper focuses on a new method for forming axisymmetric parts of considerable length in a CNC skew rolling mill. The laboratory rolling mill was used to conduct rolling tests for car axles (in scale 1:5). Although produced parts are free from internal defects such as fracture and shrinkage porosity, there occurs a local pile-up of the material leading to an increase in the workpiece diameter, as well as spiral grooves are formed, predominantly on conical surfaces. The impact of basic parameters of the skew rolling process on the formation of identified internal defects is assessed analytically and numerically. Experimental tests are performed to determine the effect of spiral grooves on the quality of final products, particularly forgings produced from skew rolled preforms.

The effect of shaft diameter on the surface quality in turning machine for different sets of cutting parameter

In the manufacturing industry, machining is the process which has been used widely within the industry for carrying out various operations. By putting the materials together, mechanical parts can be formed with the help of raw materials change and these mechanical parts used in the formation of heavy and small machineries for the personal used and for the industrial use as well.
 Most of the metals are being manufactured with the help of machining. In the process of turning, the cutting parameters gained the opportunity to increase productivity. However, there also exists a consequence regarding the quality and deterioration risk and the life of the tool which need to be controlled to achieve greater efficiencies.
 The selection of parameters is based on the materials used in workpiece, tools, and other stuff. Additionally, the size of the tool matters as well, therefore it should also be selected carefully by keeping in mind the need of the machine and capability of the users regarding managing that machine. Many factors could affect the machining performance and during turning process, workpiece diameter could be one of these factors which affect the surface quality. The main objective of this study is to investigate the role of shaft diameter on the surface quality in Lathe turning machine. Taguchi method and Analysis Of Variance (ANOVA) were used for data analysis and to optimize the cutting parameters with several experimental runs well designed. The result shows the shaft diameter effect quality of workpiece surface and the researchers should take into account this effect during their study and compare it with other researcher results.

New production technology of screw sections by drawing

The development of engineering and technology necessitates the search for new solutions related to the release of innovative products with high added value, which include long-length cold-worked screw sections. An analysis of the methods for producing long screw profiles is made, as a result of which a new method is proposed that differs from the known methods by the absence of a twisting operation for forming a helical surface. This feature of the new method for producing long screw profiles simplifies the design of the device and reduces energy consumption. The influence of the workpiece diameter and the number of passes of the helical surface on energy consumption was studied, and a comparative schedule was constructed that proves the advantages of the proposed method for producing screw sections by drawing. For the strength analysis of equipment, a dependence is proposed by which the force that occurs when drawing long screw profiles can be found, taking into account the deformation conditions and design features of the device forming the screw surface. Using the fourth theory of strength, a dependence is obtained to determine the condition that guarantees the absence of breaks in the process of drawing a screw profile.

Unapređenje procesa sabijanja kod četvorokrakih obradaka bazirano na kompjuterskom i fizičkom modeliranju

The method of upsetting of large ingots has been investigated in this work. The proposed method consists in upsetting of profiled workpieces with concave faces. An angle of the concave faces was 150°. A relative depth of the concave faces has been varied in range 15%…25% from workpiece's diameter. Strains effective and mean stresses in the longitudinal cross-section of the workpiece with concave faces after upsetting have been determined by FEM. A value of compressive stresses has been determined based on a parameter of the stress state. FEM allowed to find what a rational depth of the concave faces should be, which has to be 15 % from workpiece's diameter. Maximum closing of the internal defect take place for this depth of the concave faces. Results of the FEM have been tested by experimental investigations. It has been established that upsetting of the four-beam workpieces improved a quality of the massive parts.

Experimental investigation and optimization using regression genetic algorithm of hard turning operation with wiper geometry inserts

The major objective of today’s industries is to increase productivity and quality of product at low cost with minimum energy consumption which in turn lead to economic and eco-friendly manufacturing. Hard turning with the tool having wiper geometry possess these advantages over conventional turning process followed by a grinding process. Hard turning with wiper geometry tool is a primary metal cutting process which is extensively used for the reduction of the diameter of work piece to specified dimension and generation of smooth surface finish on the work piece material having a hardness greater than 45 HRC without supplementing it with grinding. In the present research work, for experimentation, hardened EN 24 and CBN are selected as work piece and cutting tool material respectively. Major influential process parameters viz. feed, cutting velocity and depth of cut are taken for experimentation while Material Removal Rate (MRR), Surface roughness (SR), Temperature (T) at tip of cutting tool, Strain equivalent to cutting force and feed force developed in cutting tool holder are taken as response parameter. During turning operation, surface roughness (SR), temperature, cutting strain and feed strain are desired to be minimum while material removal rate is desired to be maximum. To get the desired quality of product with minimum uses of resources, the investigation into the effect of process parameter on performance parameter and its optimization is necessary. In this research attempt, Taguchi, ANOVA, Regression techniques and Genetic Algorithm are employed to optimize the identified process parameters.

Finding dimensional stability considering deflection effects in cylindrical plunge grinding

In spite of the existence of several models to effectively design grinding cycles, they are not frequently adopted in production lines, due to the lack of knowledge, difficulties in determining some input parameters and discrepancies observed in the obtained results during the production of a batch of parts. This paper proposes a contribution to the modeling and simulation of cylindrical plunge grinding cycles in terms of dimensional stability of the process, prediction of the workpiece diameter along the grinding cycle and the minimum required spark-out time, incorporating into the model grinding tolerance limits according to the chosen capability scenario. The prediction of the part diameter and the spark-out time in a cylindrical plunge grinding operation is the key parameter to design optimized grinding cycles. The proposed model covers typical fast grinding cycles in industry, in which the spark-in time is not long enough to guarantee that at its end, the real workpiece radius reduction speed is very close to the programmed feed rate. In the proposed model, the remaining radial stock to be removed during the spark-out stage is designed to be equal to or lower than the tolerance limit for the grinding operation, but considering different scenarios of capability index: barely capable process (Cp= 1); capable (Cp= 1.3); and six-sigma quality level (Cp= 2.0). The minimum spark-out time necessary to reduce the total radial stock to the specified capability limit is calculated by the simulation. Experimental plunge cylindrical grinding tests were performed in which the reduction in the workpiece diameter was measured using an in-process diameter gauge, varying the in-feed velocity and the spark-out time. As a result, a reasonable compromise between the proposed theoretical model and the experimental data was achieved. The dependency of the “time constant” and the in-feed speed was demonstrated for fast spark-in cycles. It was also observed that longer spark-out times will be needed to achieve tighter capability indexes for a given in-feed speed and “time constant” value.

Numerical simulation of the induction heating process of a disk profile

This paper presents the developed parametric 3D model of disk heating. The numerical results reflect the change in the temperature profile of the heated pattern depending on the current value, current frequency, air gap size, workpiece thickness, workpiece diameter, heating time, number of inductor turns used and geometrical position elements of the systems “inductor - disk”. The results can be used for parametric studies and setting up the operation mode of installations for various sizes of disks.

Errors in Clamping Thin-Walled Pipe

The errors arising when thin-walled pipe is clamped in a three-jaw chuck are determined. The wraparound jaws are bored so that their internal diameter is consistent with the rated workpiece size. The workpiece is centered with minimal force. The position of the internal surface is measured with respect to 16 points, and then the clamping force is increased to the working value and the measurements are repeated. It is found that, under the action of the clamping force, the workpiece diameter is decreased by a factor of about 0.0004, while the center of the cross section is additionally shifted by about 0.0003 diameter.

Straightening of Relatively Flexible Cylindrical Parts. Part II. Stress State of the Cylinder Workpiece in Transverse Rolling between Flat Plates

The intended form of relatively flexible cylindrical parts (shafts and axles) may be restored by straightening by flexure under a distributed load, with subsequent strengthening of the workpiece by surface plastic deformation based on transverse rolling between flat plates. It is well known that the nonequilibrium stresses are generated in the whole workpiece after straightening by transverse flexure, and the part is eventually deformed again. Therefore, the workpieces should be additionally straightened with surface plastic deformation after straightening by flexure. We use transverse rolling by flat plates for that purpose. The aim in the present work is to determine the capture conditions and the stress state of the workpiece in transverse rolling of cylindrical parts between flat plates. The mathematical analysis is based on the theory of an elastoplastic solid; ANSYS Workbench software is employed. A new method is proposed for control of stress state in straightening of cylinderical workpieces. The limiting capture angle α ranging 2–8 degrees and the maximum absolute reduction depending on friction coefficient and on the diameter of workpiece are obtained. The optimum reduction varies ΔH = 0.07–0.15 mm. The calculation data show that the stress state of uniform extension occurs at the center in the workpiece cross section after transverse rolling, and the stress state of reduction is formed at the peripheral areas of the workpiece. The straightening method of transverse rolling between flat plates eliminates crack formation and destruction of the material in the central area of the cylindrical parts.

Modeling the techological process of pipe forging without a mandrel

A broaching technique for thick-walled pipes has been investigated. The proposed technique implies the deformation of a hollow workpiece without a mandrel. The procedure has been devised to conduct theoretical studies using FEM. The procedure is aimed at determining the thermal, stressed state and a shape change in the workpiece while forging pipes without the use of a mandrel. The variables applied were the internal diameter of a hollow workpiece, which ranged in the interval of 0.30; 0.55; 0.80. Based on the finite-element modeling, the following was established: the distribution of temperatures and intensity of logarithmic deformations within the volume of a pipe after broaching without the use of a mandrel. The diameter of a pipe’s hole has been determined, which is formed at broaching when applying a given technique. The dependences of intensity of lengthening and thickening of the wall of a pipe have been established. A special indicator was devised to estimate the elongation rate of a pipe. It was determined that increasing the inner diameter increases the lengthening of a pipe and decreases the intensity of the hole forging. The common dependence for the simulated broaching schemes is that the magnitude of elongation of a hollow workpiece changes insignificantly for different degrees of reductions at constant relative sizes of a pipe. It has made it possible to establish a recommended feed in order to increase the elongation of a hollow forging and to decrease the degree of closing a hole. The rational feed shall be (0.05...0.15)D. The results from the finite element modeling were verified by experimental study using lead samples. An experimental modeling procedure has been devised. It was established that at an inside diameter of the workpiece of (0.5...0.6)D one observes a maximum of the wall thickening. It was established that the results for a workpiece shape change, obtained from a theoretical study using FEM, exceeded those acquired experimentally by 9.14 %. The validity of results from theoretical modelling is confirmed by data from experiments on decreasing the internal diameter of the pipe. Difference between the theoretical and experimental results amounts to 9...12 %. The established patterns make it possible to determine the resulting diameter of a pipe’s hole. It was found based on the results from modeling that it is impossible to broach pipe workpieces without a mandrel. This technique extends the possibilities of technological processes aimed at manufacturing pipe workpieces.

Simulation methods for skew rolling

Abstract A number of different rolling processes are summarized under the term skew rolling. The process variant investigated in this paper is an incremental flexible rolling process with kinematic forming of the geometry. Two sets of actively driven work rolls are used in a transverse rolling process to selectively reduce the diameter of a cylindrical workpiece to form circumferential grooves. Simultaneously, the excess material is pushed in axial direction, thereby forming a bulge that can be used to join e.g. a gear wheel onto an axle. Since this is done in a cold rolling process the positive influence of the induced residual compressive stress as well as strain hardening can be used to improve fatigue strength of the workpiece under cyclical loads. The authors discuss the advantages of this hybrid skew and cross rolling process and propose a simplified numerical model to quickly analyze process parameters like axial and radial work roll feed and the influence of initial stress profiles in the workpiece. The model uses a 2 ½ D axis-symmetric approach in LS-Dyna R10.1.0 with implicit solver. Additionally, preliminary results of first tests on rolled specimen from 42CrMo4 are briefly discussed.