Workpiece Size 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.

Optimization of Machining for the Maximal Productivity Rate of the Drilling Operations

Machining processes focused primarily on the quality of surfaces and sizes of machined workpieces, as well as minimizing costs and tool wear. Existing publications related to maximizing the productivity of machining processes, present results that are in fact sub-optimal. The increase in machining regimes improves productivity but may reduce the quality of machined products. Mathematical optimization methods help find a balance between the benefits and drawbacks of machining processes. The tool life of cutters largely influences machining productivity and sets limits on machining speed. The normative tool life equations developed in research labs do not take into account the reliability of machine units and the specificities of technological processes. The normative machining speeds are suboptimal for manufacturing processes and may not maximize productivity. This paper presents a mathematical model for optimizing the cutting speed of a drilling machine tool to achieve its maximum productivity under realistic manufacturing conditions.

Effect of grain size and cobalt content on machining performance during milling tungsten carbide with PCD tool

Tungsten carbide has been extensively utilized in the manufacturing field due to its exceptional properties. However, traditional methods such as grinding or electric discharge machining often result in a low material removal rate and inevitable surface defects, making tungsten carbide one of the most challenging materials to machine. Milling has emerged as a promising alternative for machining tungsten carbide. However, the milling of tungsten carbide has not been widely applied in the industry due to a lack of comprehensive understanding regarding the milling performance of different tungsten carbides under various conditions. In this paper, a polycrystalline diamond (PCD) tool was used in the milling of tungsten carbides to investigate the effects of tool grain size, workpiece Co content, and WC grain size on tool wear and machining surface quality. It was found that PCD tools with larger grain sizes exhibited higher wear resistance. Additionally, excessive Co content in the workpiece and large WC grain size increased tool wear and degraded the quality of the machined surface. The primary types of tool wear observed in the milling of WC-Co included adhesive wear, abrasive wear, phase change wear, and oxidation wear.

Research on Online Measurement Method for Small Workpiece Circular Holes Based on Machine Vision

<p>In modern manufacturing, due to the narrow format, short size, and complex surface structure of small-sized workpieces, automatic detection of surface defects, dimensions, etc. on small-sized workpieces faces difficulties, making it difficult to meet the requirements of fully automated production lines. Especially, there is no good solution to the problem of high-precision automatic measurement of geometric features of circles and arcs on small-sized workpieces. This article takes the engine end cover circular hole thermal component as the research object, builds a hardware platform for image acquisition of small-sized workpieces based on machine vision, proposes an online size measurement method for small-sized circular holes, and realizes the measurement of the position size and aperture size of small-sized product shell workpieces. In order to achieve the above methods, this article builds a visual detection hardware system and describes a detailed machine vision hardware selection scheme. Then, the images collected by the system are preprocessed, including image denoising, image correction, and image feature extraction. Then, for the processed images, an improved Hough transform fitting method is used to obtain the online size of features. In order to visualize the results, the detection system and software are designed according to the actual application scenario. The overall scheme of this article is efficient and reasonable, and the detection result error is within a reasonable range.</p> <p> </p>

Optimization Scheme of Measuring Accuracy of Bearing Seat Size Based on Machine Vision

At present, the size measurement of industrial workpieces is mainly manual measurement and CMM measurement, which cannot meet the requirements of high precision, high efficiency and low error rate in industrial production at the same time. In order to solve the above problems, this paper uses monocular vision technology to propose an optimization scheme of workpiece size measurement accuracy based on machine vision, which takes the height and declination Angle between the camera lens and the workpiece as variables. Firstly, the image was captured by camera calibration correction, and morphological methods such as gray-scale, denoising, expansion and corrosion were used for image pre-processing. Secondly, features were extracted using double-threshold canny edge detection algorithm and connected domain algorithm. Finally, the bearing seat size was measured using the minimum external rectangle algorithm. The experiment shows that the higher the distance between the camera lens and the stage, the larger the error is when the image information can be collected completely. The greater the Angle between the center of the camera lens and the center of the workpiece, the greater the error; The device not only meets the precision requirements, but also has the advantages of fast response speed, which can meet the needs of industrial applications.

Numerical investigation of elastomeric solid cutting: Enhancing cut initiation for minimally invasive biological tissue cutting

Abstract Minimizing tissue damage during blade cutting is vital for optimal surgical outcomes. However, the elastomeric properties of tissues require that they be considerably deformed before cut initiation, resulting in physical damage. Thus, the blade indentation depth required for cut initiation must be reduced by enhancing the cut-initiation ability of a process. In this study, factors that influence the cut initiation of elastomeric solids are identified by investigating the tensile stress states beneath the blade that trigger cut initiation. Finite element simulations are used to analyze interfacial interactions between the blade and workpiece and their relation to the stress states. Results show that the distribution of the in-plane stretch of the workpiece surface along the blade surface plays a key role in determining the stress states and the resulting cut-initiation ability. The effects of process parameters, including interfacial friction, blade tip geometry, blade motion, and workpiece size, are examined and discussed by analyzing the corresponding in-plane surface stretch distribution. This study offers a fundamental understanding of cut initiation in elastomeric solid cutting for improving surgical cutting tasks.

The effect of heat input on tensile strength, Vickers hardness, and microstructure on DMW of AISI 1015 and 304L SS through the GMAW process

This experiment was to evaluate the effect of heat input on tensile strength, Vickers hardness, and microstructural observations.The materials welded are AISI 1015 and 304L SS, and the joining process is Gas Metal Arc Welding (GMAW). The filler electrode used is ER70S-6 with a diameter of 1.2 mm, and the workpiece size is 300 x 125 x 3 mm with a butt-joint connection. The variations in welding current applied are 120, 130, and 140 A. Meanwhile, the voltage and welding speed in the experiment were kept constant.The maximum tensile test index was 380.08 MPa, and the Vickers hardness index was 376.85 HV, with the maximum heat input being 0.5943 kJ/mm. The macro- and microstructure, as well as structural inspection of the welded joints, were observed in the experiment. The best heat input effect for the DMW technique between 304L SS and AISI 1015 is 0.5943 kJ/mm at a plate thickness of 3 mm.Dissimilar Metal Welding (DMW) is widely applied in the power generation industry. Materials generally joined using the DMW technique are austenitic stainless steel (304L SS) and low carbon steel (AISI 1015).Using the proposed heat input approach is important for the dissimilar welding industry application to obtain the right product for its expected use.This paper presents the differences in heat input to reveal the weld properties by dissimilar welding processes, where the properties will be adapted for a particular use. Particularly in the application of dissimilar joints between 304L SS and AISI 1015 with a thickness of 3 mm, which requires an average tensile strength of around 380.08 MPa and an average yield strength of about 320.16 MPa, the heat input parameter can be recommended as 0.5943 kJ/mm.

Effects of workpiece size on bending angle in laser forming of al 6061-T6 sheet

In the laser forming process, the effect of workpiece size, including variations in width and length, plays a crucial role in determining product quality. To better understand the deformation behavior and obtain the desired bending angle with varying workpiece sizes, the size effect on laser forming of Al 6061-T6 aluminium alloy has been investigated. Due to the fact that Al 6061-T6 alloy sheets have more deformability and high strength properties, they have been studied in this paper. A three-dimensional numerical model that considers temperature-dependent properties of the material, and convection-radiation heat losses is constructed to investigate the sheet deformation. The numerical model is verified by performing experimental tests under the considered operating conditions. The suggested model is found to be in reasonable agreement with the experimental findings, and it is shown to have a maximum error less than 8 % when predicting the bend angle. Computed results through the numerical model show that the bending response is increased with the increase in workpiece width; however, it is marginally affected with workpiece length. Based on simulation results, the edge effect is also explored in relation to workpiece size. Edge effect increases as sheet width increases; whilst it decreases as sheet length increases. This investigation will be helpful in laser-based forming industries for obtaining desired bending of Al 6061-T6 sheets.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ВЗРЫВНОЙ ОБРАБОТКИ ПОЛИМЕРА НА ПРОЧНОСТНЫЕ ХАРАКТЕРИСТИКИ ПОЛУЧАЕМЫХ ЖЕЛЕЗОФТОРОПЛАСТОВЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ

The results of studies on the effect of polymer explosion treatment on the physical and mechanical properties of ferrofluoroplast composite materials are presented. It is shown that the compressive strength of materials obtained using blast treatment is higher than that of similar materials compacted by static pressing. Optimal temperature and time parameters of sintering of ferrous-fluoroplastic materials have been established, providing high strength and stability of geometric shapes and sizes of workpieces.

GEOMETRIC ANALYSIS AND DESIGN OF FLAT FORM TOOLS

Form tool means a cutting tool which is appropriate manufacturing of workpieces having more complicated geometry. The contour of manufactured workpiece is manufactured by the tool profile. This cutting tool can be used in case of serial and quantity production. The advantageous of their usage are the lower turning time and the lower standard deviation of the workpiece sizes. The reached accuracy on the workpiece is independent from the qualification of the worker. The aim of this publication is the explanation of the geometric analysis and the design by analytical and constructional way. This type of tool is advantageously usable for manufacturing on CNC machine or conventional machine.

Mathematical Modelling and Multiresponse Optimization to Minimize Surface Roughness in Drilling Custom 450 Stainless Steel

In the present study, drilling tests were carried out on Custom 450 stainless steel workpieces. The influences of control factors (cutting speed-Vc, feed rate-f and drill bit geometry-D) on the drilled holes’ surface roughness (Ra) and on the size of adhering workpiece (AW) to the drill bit was examined. The results obtained from tests designed based on the Taguchi’s L16 orthogonal array were analysed using ANOVA and grey relational analyses (GRA). Therefore, the control factors and their levels were optimised simultaneously for the quality characteristics (Ra and AW). In addition, mathematical models were also developed using Response Surface Methodology (RSM) in order to estimate the quality characteristics. The used drill bits were examined under digital and scanning electron microscopes and EDX analysis was also carried out on the drill bits. The experimental results showed that the Ra and AW increased with increasing the f. It was also seen that increasing the Vc resulted in decrease in the size of adhering layer and that the drill bit wear became clear at the highest Vc of 60 m/min. According to the ANOVA results, the most effective control factor on Ra was f with 93.11% and Vc with 58.14% on AW. GRA analysis revealed that the most influential control factor was the f and that the optimum levels were 60 m/min Vc, 0.005 m/min f and drill bit 4.

Dynamic model and machining mechanism of wire sawing

During the wire sawing process, the wire usually undergoes large deformation, which leads to changes in the sawing force and the contact state between wire and workpiece, and in turn affects the material removal rate (MRR) and the workpiece quality. This paper presents a general dynamic model for the wire sawing. The model aims to describe the coupling relations among the contact state of wire and workpiece, the sawing force and the material removal. An iterative simulation flow was designed by the proposed model. The experiment of wire sawing with rocking and reciprocating (WSRR) was carried out to validate the proposed model. The comparison results indicated that the proposed model replicated the entire sawing experiment well. On this basis, the influences of wire speed, feed rate, rocking angle, preload force, guide rollers distance and workpiece size on sawing force, contact length and MRR were systematically analyzed. The results show that the wire reciprocating is the root cause of saw marks. Workpiece rocking causes the wire bow angle to change periodically and significantly reduces the contact length. Wire speed and feed rate has great influence on the value of normal force. The force fluctuation is affected by the maximum rocking angle and wire preloading force. MRR is mainly determined by the feed speed. The feed rate, maximum wire speed, maximum rocking angle, and preloading force could influence on the fluctuation range of the MRR. This work provides a general model for a better understanding of the wire sawing.

Parameters of the extraction of a thin-walled glass made of corrosion-resistant steel 12X18N10T

Methods of metal processing by pressure are one of the most advanced technological methods of manufacturing thin-walled spatial parts. The volumetric stamping methods used ensure high productivity while maintaining product quality. Cold volumetric stamping is one of the main types of metal forming in many branches of mechanical engineering, as it most fully meets the requirements of approximating the shapes and sizes of workpieces to finished parts. Determining the rational technology of the stamping process is a fundamental factor in the development of the production of a new product. Hollow parts with a bottom of the "glass" type are usually obtained by direct or reverse extrusion. The maximum deformation and minimum wall thickness of the part in this case is determined depending on the technological deformability of the workpiece. The design of technological processes of cold volumetric stamping of thin-walled parts of the "glass" type involves solving a number of complex tasks: determination of the stress-strain state; determination of punching forces, loads, etc. The use of traditional methods of designing technological processes of cold volumetric stamping does not always allow us to solve these tasks and ensure the optimal combination of the required quality of the finished part and the minimum time and cost of production. One of the effective approaches to solving these problems is the use of computer-aided design systems based on computer technologies: CAD and SAE systems - software complexes for automated engineering analysis of volumetric stamping processes.

Wire-EDM geometrical simulation based on superposition of single craters

Setting EDM technology parameters is a time consuming and expensive process. The development of a process model facilitates the understanding of the input parameters on the process results, which can speed up the selection of the optimal technology for a cut. This work aims to model the wire-EDM machining process with a three-dimensional geometrical voxel model through the sequential placement of single craters. To model workpiece sizes closer to reality, 2.25 109 voxel elements are used to construct the virtual workpiece. The simulation showed that under the same pulse energy conditions, main cut simulations have a smaller average roughness compared to trim cuts, a claim that is supported by experiments presented in this work. This disparity is related to the direction of the craters imposed by the geometrical conditions, i.e. the position of the wire relative to the workpiece. Furthermore, the simulation showed proportional roughness values compared to the experimental ones, though always underestimating the roughness value. This difference emerges because the model, as it does not incorporate the build up around the craters that might appear on the surface.

An AFM-based methodology for planar size and local 3D parameters of large workpieces

The existing size measurements of large workpieces have drawbacks of slow speed, low-precision, and separation of planar size and 3D parameters measurements. An automatic flight measurement (AFM)-based methodology was proposed to measure large workpieces' planar and local 3D parameters. Firstly, the automatic flight path planning of the measured workpiece is carried out through shape decomposition before acquire the images with a bi-telecentric lens. Then, we measure the planar size of the workpiece through zero-crossing point (ZCP) feature contour extraction, and parameter fitting. Finally, we achieve local 3D parameter measurement through the seed point search algorithm to extract laser lines, system calibration, and the point cloud data (PCD) processing. We also measured the curvature and roughness of the curved workpiece. The experimental results obtained from multiple large-size workpieces show that the plane error of the method in this paper is within 0.05 mm within the measurement range of 216 mm × 236 mm, and the relative error of the local height measurement is within 1 %. Therefore, the proposed method has strong adaptability and robustness and can meet the measurement requirements of the large-sized plane and curved workpieces.

Deep transfer residual variational autoencoder with multi-sensors fusion for tool condition monitoring in impeller machining

The data-driven deep learning models show incomparable superiority in tool wear monitoring. However, facing the monitoring environment of real-time changes in tool model, workpiece size, and cutting parameters in the machining of centrifugal compressor impeller, the flexibility of the model between different tools is rarely considered. In this manuscript, a novel deep transfer learning model based on residual variation autoencoder (Tresvae) with multi-sensors fusion signals is proposed. The sound pressure signals, acceleration signals, and spindle motor current signals are collected and confused into images as monitoring samples. Moreover, the residual network is used to optimize the encoding part of the variational autoencoder network while the decoding part remain unchanged. Then the parameter transfer strategy is adopted to realize the model transfer diagnosis between different tools. Experiments show that the proposed model achieves superior identification results than other methods on the same types and different types tools monitoring in impeller machining. Among them, the maximum recognition accuracy of the same type of tools is 97.25%, and that of different types of tools is 92%.

Accurate vibration-free robotic milling electric discharge machining

Traditional computer numeric control (CNC) machines have high accuracy but are limited by workpiece size and axes. Therefore, many researchers attempted to equip six-axis industrial robots (IRs) with milling end-effectors to explore the robot’s large and flexible working envelope. However, IRs lack stiffness and have limited force, resulting in low accuracy, poor surface roughness (SR), and low material removal rate (MRR). On the contrary, electric discharge machining (EDM) is a non-conventional process capable of shaping complex profiles in any conductive material. Since the EDM process has no physical contact between the electrode and the workpiece, it can machine diverse hard-to-cut materials accurately and free of vibration. However, to this day, EDM is found in limited conditions of CNC machines only. Thus, this research investigates a synergistic combination of IR and milling EDM. Adopting advanced CAM tools and offline programming, it examines pre-designed electrodes working analogue to conventional milling to perform the desired machining by intricate cutting paths. The results deliver a robotic machining technique able to cut hard materials using small industrial robots yet free of vibration and not pose dependent.

Research on Grinding Parameters of Parts with Same Clamping Mode and Different Sizes

Aiming to study the influence of ultra-precision grinding parameters on the accuracy between the same clamping method and different workpiece sizes. This paper mainly analyzes the difference between the measurement precision of different parts by the same measurement method and the measurement precision of the same parts by different measurement methods. Therefore, the influence of grinding parameters on grinding precision is reflected. For the same part, it is concluded that the coaxiality error coincidence degree at end A and end B reaches 90.32% and 95.27%, respectively by using precision three-coordinate measuring instrument and Mahr roundness instrument. The coincidence degree of end A and end B verticality error reached 97.54% and 91.08%, respectively. For parts with different sizes, the Mahr roundness meter is used for measurement. The analysis shows that the coaxiality coincidence at end A and end B is the highest, reaching 98.36% and 92%, respectively. And from the analysis, the errors are mainly reflected in the factors such as jig and fixture and grinding process.

ВЛИЯНИЕ ПАРАМЕТРОВ УДАРНОЙ СИСТЕМЫ, РАЗМЕРОВ И МАТЕРИАЛА ОБРАБАТЫВАЕМОЙ ДЕТАЛИ НА ЭФФЕКТИВНОСТЬ ВОЛНОВОГО ДЕФОРМАЦИОННОГО УПРОЧНЕНИЯ (МОДЕЛИРОВАНИЕ)

The article is devoted to the study of the influence of the workpiece size and material as well as deformation waves generated in shock systems with a different ratio of the striker and waveguide lengths (L1/L2 = 3, 5, 10), on the effectiveness of wave deformation hardening (VDH). The peculiarity of this technology is the periodic impact on the surface to be strengthened by waves of deformations generated in the shock system. The research was carried out using finite element modelling. To achieve this goal, models of the machined material (Steel 45, Titanium VT 1-0, Bronze BrAZH 9-4, Aluminum V95), shock pulse generation, wave deformation hardening process were developed. The effectiveness of the VDH was estimated according to the values of the degree and depth of hardening calculated as a result of modelling. The conducted studies showed that the material thickness of the machined sample has the most significant effect on the hardening efficiency among the geometric parameters. The use of shock systems with a ratio of L1/L2=5, compared with L1/L2=3 and 10, with the equal impact energy, allows to obtain large values of the degree and depth of hardening.

Application of Frequency Control Techniques for Hot Tensile Testing in Induction Heating

This paper proposes the frequency control technique using a half-bridge resonance inverter for hot tensile testing in induction heating. The technique involves power regulation, high frequency pulse, frequency adjustment, and pulse generator controller based on the dsPIC33FJ16GS404 chip IC. Significantly, the inverter is controlled by two sections. Throughout the heating cycle, the first controller retains the inverter's operating frequency slightly above the resonant frequency, while the second keeps the phase angle of the current and voltage output in check to control the output power at a level suitable for changes in the tensile parameter workpieces. As a result, the inverter improves the efficiency of the prototype, which has 1.5 kW input power. Furthermore, it can heat three different sizes of steel workpieces for hot tensile testing, with diameters of approximately 3, 5, and 10 mm and lengths of approximately 50 and 70 mm, respectively.