Types Of Workpiece Materials Research Articles

Investigation the plastic flows in the metal stamping-drawing process at the die corner

The present investigation covers the study of the influence of metal-plastic flow on the die corner for the deformed state of the blank and energy-power parameters during stamping-drawing. The influence of workpiece size and material on stress intensity and maximum deformation force has also been investigated both experimentally and theoretically. In addition, simulation of the stamping and drawing process was also presented. One type of die, with variations in diameter are considered different in the drawn part size and for each standard size four types of workpiece materials have been considered. The stamping process continued until the part failed structurally. The predicted test results show a dependence of the maximum load and stress intensity on both the diameter of the blank and the yield strength of the alloys and these data are in agreement with the actual measured values. Then, the method for calculating the processes of plastic deformation of metals based on a closed set of equations of continuum mechanics is proposed for the theoretical study of energy-power parameters of the technological processes. Comparison of the results of a full-scale experiment, simulation of metal flow at the die corner and theoretical calculations shows that the proposed theoretical model gives satisfactory results and can be effectively used for engineering calculations.

Influence of clean cooling medium on the hard drilling performance and machined surface integrity of 42CrMo steel

42CrMo ultra-high strength steel has high strength and fracture toughness, which is widely used in key components, such as gears, connecting rods and molds. This type of workpiece material, especially after quenching and hardening treatment, still has prominent issues with hole machining. In this work, the clean cutting media, including dry, cold air and liquid nitrogen (LN2), are selected to investigate the hard drilling performance and machined surface integrity of 42CrMo steel. The feasibility of extending tool life and improving hole machining quality is explored through clean cooling medium. The cutting force and cutting temperature are lower under cold air and LN2 conditions than that under dry cutting conditions. The tool life is extended under cold air and LN2 conditions. The low temperature brought by LN2 promotes the transformation from folded to lamellar for chip free surface. The degree of chip curling becomes larger and easier to break and discharge, which reduces the unfavorable effects of chip clogging. The thermal damage phenomenon on the hole wall surface is disappeared. The surface roughness is reduced by 37.3%, and the maximum microhardness is increased by 6.6%, which significantly improves the machined surface integrity of holes. This work demonstrates the feasibility of improving the machinability of harnessed ultra-high strength steel by LN2 cooling.

Predictive Modeling for Machining Power Based on Multi-source Transfer Learning in Metal Cutting

Energy efficiency has become crucial in the metal cutting industry. Machining power has therefore become an important metric because it directly affects the energy consumed during the operation of a machine tool. Attempts to predict machining power using machine learning have relied on the training datasets processed from actual machining data to derive the numerical relationship between process parameters and machining power. However, real fields hardly provide training datasets because of the difficulties in data collection; consequently, traditional learning approaches are ineffective in such data-scarce or -absent environment. This paper proposes a transfer learning approach for the predictive modeling of machining power. The proposed approach creates machining power prediction models by transferring the knowledge acquired from prior machining to the target machining context where machining power data are absent. The proposed approach performs domain adaptation by adding workpiece material properties to the original feature space for accommodating different machining power patterns dependent on the types of workpiece materials. A case study demonstrates that the training datasets obtained from the fabrication of steel and aluminum materials can be successfully used to create the power-predictive models that anticipate machining power for titanium material.

Review on the behavior of various parameters on heat distribution in the SAW process

The submerged arc welding (SAW) process comprises a formation of an electric arc between the wire and a weld joint surface. The electric arc and weld joint completely covered by the flux. The composition of flux varies with the type of workpiece material. The heat distribution on the welded joint area, significantly affected by the various welding parameters such as penetration, bead width, heat affected zone, etc. This article covers the summarized report of research conducted in the last two decades in the field of fusion welding and more emphasis on the SAW process. The various weld parameters that are penetration, reinforcement of weld bead, percentage dilution, bead width, heat affected zone significantly affect the quality of the weld and joint strength. The article highlights the variation in these variables and is optimized to control the quality of weld in terms of penetration, percentage dilution, reinforcement of weld bead, etc. There are various software to simulate the joint characteristic under variation in different weld variables also discussed. The SAW process is mostly used in the field of pipelines, offshore structures, pressure vessels, LPG cylinders. The most significant cause of SAW popularity is its higher metal deposition rate and flowless weld seam. It is observed that by increasing the arc length, because of the expansion of the arc cone, penetration increases. Similarly, significant variations are observed by changing the welding feed rate, welding current, electrode polarity and other factors.

An investigation into methods for predicting material removal energy consumption in turning

Abstract The wide use of machining processes has imposed a large pressure on environment due to energy consumption and related carbon emissions. The total power required in machining include power consumed by the machine before it starts cutting and power consumed to remove material from workpiece. Accurate prediction of energy consumption in machining is the basis for energy reduction. This paper investigates the prediction accuracy of the material removal power in turning processes, which could vary a lot due to different methods used for prediction. Three methods, namely the specific energy based method, cutting force based method and exponential function based method are considered together with model coefficients obtained from literature and experiments. The methods have been applied to a cylindrical turning of three types of workpiece materials (carbon steel, aluminum and ductile iron). Methods with model coefficients obtained from experiments could achieve a higher prediction accuracy than those from literature, which can be explained by the inability of the coefficients from literature to match the specific machining conditions. When the coefficients are obtained from literature, the prediction accuracy is largely dependent on the sources of coefficients and there is no definitive dominance of one approach over another. With model coefficients from experiments, the cutting force based model achieves the best accuracy, followed by the exponential function based method and specific energy based method. Furthermore, the power prediction methods can be used in process design stage to support energy consumption reduction of a machining process.

Performance of Diamond and Silicon Carbide Wheels on Grinding of Bioceramic Material Under Minimum Quantity Lubrication Condition

Advanced ceramic materials like sintered and presintered zirconia are frequently used in biomedical applications, where minimum quantity lubrication (MQL) assisted grinding is required to achieve a good surface finish instead of conventional flood coolant. However, insufficient cooling and wheel clogging are the major problems that exist in the MQL grinding process, which depends upon the type of work piece material and the grinding wheel being used. The present study is to determine the performance of the grinding wheels on presintered zirconia under MQL conditions in terms of grinding forces, specific energy, surface integrity, and wheel wear. Experiments are conducted with two different types of grinding wheels as silicon carbide (SiC) and diamond grinding wheels under the same condition. The results indicated that the diamond wheel provided a better surface finish and reduced tangential force under MQL condition, compared to the conventional SIC wheel. This was due to the reduction of wheel loading in the diamond grinding wheel. The specific energy of diamond grinding wheel was reduced with higher material removal rate compared to the conventional SiC wheel. The ground surfaces generated by the diamond grinding wheel showed fine grinding marks with better surface finish. The percentage of G-ratio calculated for the diamond wheel was higher than the SiC wheel by 77%. This was due to the sliding of the grains and less wheel loading in the diamond wheel. The cost difference between the corresponding wheels was discussed to improve the productivity of the grinding process.

Three dimensional topographic studies on worn surfaces of coated cemented carbide tools with different workpiece materials

Different worn surfaces were observed when machining different types of workpiece materials using similarly coated cemented carbide inserts. This study focuses on the flank wear within the coating. A clear difference in wear patterns were observed on worn surfaces depending on the workpiece material used. The worn surface was characterized by 3D surface topography using white light interferometry. Additionally, TEM studies were used to increase the understanding between the relations of the workpiece materials to the resulting worn surfaces. The added information from the worn surfaces and TEM investigations can help in better understanding the wear mechanism when machining different workpiece materials.

Study on Applicability of Large-Area EB Irradiation to Micro-Deburring

In a large-area electron beam (EB) irradiation method developed recently, high energy EB can be obtained without focusing the beam, and large-area EB with almost uniform energy density distribution of 60mm in diameter can be used for instantly melting and evaporating metal surface. Then, the surface smoothing and surface modification of metal molds made of steel, cemented carbide and ceramics can be performed efficiently. When the large-area EB is irradiated to a sharp edge, the material removal remarkably progresses at the edge due to the heat accumulation and EB concentration there, which leads to the edge rounding. Our previous study clarified that micro-deburring was also possible by using this phenomenon. Moreover, this method would be effective for removal of discontinuous micro burrs generated by thermal machining processes, such as EDM and laser cutting. In this study, the possibility to completely remove micro burrs generated in EDM was experimentally investigated. The difference in micro-deburring characteristics with the type of workpiece material was also investigated. As a result, the EDM micro burrs with a height of about up to 50μm could be completely removed by this method. Furthermore, it was made clear that the magnetic property of workpiece materials greatly influenced the deburring characteristics, and the thermal property such as melting point and thermal conductivity also did.

Development of an AE-based system for workpiece datum determination on a micro milling machine

One of the challenges of micro machine tool’s development is the difficulty associated with the determination of workpiece datum. Touch trigger probes are used in combination with laser measurement systems on standard size machine, but this method is not suitable for micro machine. Hence, in this paper, an acoustic emission (AE)-based system was developed for workpiece datum determination on a micro milling machine, integrated with and implemented on the machine’s controller and evaluated. This system was found to be highly accurate and repeatable on various types of workpiece materials using a variety of tool sizes. In all cases the system was able to detect the tool-workpiece datum to an accuracy of 1 µm, using a step size of 1 µm.

Vision-based surface roughness inspection of machined aluminium parts

This article presents an experimental research project which aims to control the roughness of aluminium parts produced by high-speed milling using vision data. A CCD camera is used to acquire images and a suitable processing system which uses machining data helps deriving information needed to estimate the surface roughness. A preliminary study on effect of machining parameters on part surface quality shows that roughness is influenced primarily by the feed per tooth, followed by the coating type used, and lastly, by workpiece material. In view of this information, we implemented a data processing tool allowing real-time roughness estimation based on the image captured by a camera and the feed per tooth. This tool takes into account the type of workpiece material and the cutting tool used (coatings and geometry). The results are in good agreement with data obtained using a traditional contact measurement system. The overall results of this study would encourage developments in the field of robust 3D vision system for online measurement of roughness for industrial use.

Surface Texturing of Tribological Interfaces Using the Vibromechanical Texturing Method

Modifying the surface topography of tribological interfaces has the potential to improve the friction performance of certain mechanical components that experience sliding contact. Vibromechanical texturing (VMT), an improved texturing method based on the convenient turning process, is introduced. This process is performed on a standard computer numeric controlled (CNC) lathe, which is retrofitted with a piezoelectric-actuated tool positioning stage. Controlled vibratory motion of the tool is used to cut microsized dimples into the surface of the workpiece. Two types of workpiece materials are used: aluminum and hardened steel, with three forms of workpiece geometries: outer cylinder, inner cylinder, and flat/end face. The accuracy of the texturing method is compared with a basic surface topography model, which predicts texture dimensions within an 11% error for aluminum and up to 90% error for hardened steel, using the current open-loop control system. Further analysis of the textured samples shows no significant signs of process-induced damage. It is demonstrated that this VMT method is a versatile, accurate technique that has potential to be a cost-effective means for surface texturing of tribological components.

Analysis of contoured holes produced using STED process

Recent developments in air engines call for more efficient means of turbine blade cooling to have higher power generation for the same unit size with increased inlet air temperature. To allow the turbine to operate at higher temperature, thousands of cooling holes are drilled in turbine blades. In order to increase heat transfer in cooling holes, the present design demands the wall of the cooling passage should be provided with contoured ribs. These irregularities help in inducing turbulence in the flow of cooling air, thereby increasing the rate of heat transfer. For drilling these kinds of contoured deep holes in a turbine blade made of material such as Inconel, the conventional drilling techniques are not suitable. The shaped tube electrolytic drilling (STED) is used to perform the task of drilling contoured holes in difficult-to-machine materials. In the present case, contoured holes are drilled by using two distinct feed rates f 1 and f 2 alternately (f 1 > f 2) and two types of workpiece materials, namely stainless steel and Inconel superalloy. Experimentally obtained profiles are compared with the profiles derived theoretically from the basic electrochemical machining equations. Quality performance factor is evaluated for the machined holes to find the best hole profile. From the present study, it has been observed that by varying the process parameters (viz., voltage (V), faster feed rate (f 1), and slower feed rate (f 2)) during drilling and fixing different step lengths, various types of hole profiles can be generated using STED process.

Challenges facing surface engineering technologies in the cutting tool industry

At the advent of the new millennium cutting tool manufacturers are finding themselves supplying tools to a market that demands ever increased performance and reliability. Technological advances in machine tool design, tool control and monitoring systems have helped facilitate the development of high-speed machining, near net machining of difficult to cut materials and dry cutting methods. Parallel advances in cutting tool technology have aided these developments with the application of surface engineering technologies being of prime importance. The current paper considers the shift in workpiece material type used in manufacturing and the subsequent change in the cutting tool materials used to machine them. To take full advantage of the potential benefits of advanced surface engineering treatments the need to address the requirements of a cutting tool in terms of geometry, substrate material, edge preparation and surface treatment are described with reference to TiN coating of high-speed steel circular saw blades. Current trends in cutting tool technology are then considered together with the benefits and practicalities of applying advanced surface engineering coatings.

ワイヤ放電加工のワイヤ温度分布計測の試み 第２報 加工中のワイヤ平均温度

To prevent the wire breakage during Wire EDM there should be information of the wire temperature because it is said that the wire may be broken by increasing of wire temperature. In our previous report we tried to measure the wire temperature distribution from discharging currents and voltage between the upper and the lower contactors contacting to the wire and averaged wire temperatures of 100°C or less were obtained. But these data were not calibrated and were not precise enough.In this report we retry to obtain precise averaged wire temperatures for two types of power supplying methods. In the first method the power is supplied from the lower contactor and in the 2nd the power is supplied simultaneously from the upper and the lower contactors. Also two types of workpiece materials, SUS304 and SKD11 are machined and results are compared. Wire temperatures are calibrated. It was found that during Wire EDM the wire resistance facing to the workpiece is greater than the static value and especially great in the case of ferromagnetic workpiece. Obtained averaged wire temperatures were almost 100°C at the maximum cutting speed for any cases.

Interrelationship between processing, coatingproperties and functional properties of steered arc physically vapour deposited (Ti,AI)N and (Ti,Nb)N coatings

In the framework of a European BRITE Project on “steered arc ion plating forthe development of new ternary and quaternary ceramic coatings for cutting and forming tools”, (Ti,Al)N and (Ti,Nb)N coatings were developed and optimized. The relation between bias voltage, N, pressure and composition of the coatings was established. Coating properties such as composition, crystal structure, lattice parameter, internal stress, Young's modulus and hardness measured by nanoindentation were determined. The oxidation behaviour of (Ti,Al)N and (Ti,Nb)N was investigated with Auger electron spectroscopy. The performances of industrial TiN coatings and these new ternary coatings deposited on high speed steel substrates were compared in drill tests. (Ti,Al)N made by the steered arc appears to be more oxidation resistant than TiN and (Ti,Nb)N. Laboratory wear tests and field tests indicate that the interaction between workpiece and coated tool may give important clues as to the suitability of a coating type for a particular type of workpiece material.