Workpiece Dimensions Research Articles

Ultrasonic detection method based on flexible capillary water column arrays coupling

Conventional water immersion ultrasonic testing faces limitations due to factors such as environmental conditions, workpiece dimensions, corrosion, and resource wastage. Contact-based coupling methods, which employ coupling media or specific coupling structures, offer a convenient approach to coupling acoustic waves and reduce signal attenuation. However, these methods are time-sensitive and lack adaptability to uneven surfaces, particularly when dealing with workpieces featuring subtle undulations, resulting in significant signal decay. This paper presents an ultrasonic coupling method based on a flexible capillary water column array. By employing a stable and flexible water column array within the micro-channels as the coupling medium, stable contact-based transmission of ultrasonic signals is achieved. The influence of water column array unit dimensions and array structures is explored through theoretical analysis and experimentation, demonstrating lower energy attenuation compared to reductions in water column area. Notably, the tests revealed the method’s adaptability at oblique angles below 20 degrees, which surpasses the performance of submerged detection at similar angles. This research presents an innovative and stable approach for contact-based ultrasonic coupling testing, particularly in scenarios involving dynamic contact scanning between ultrasonic waves and workpieces.

Structural Phenomena Introduced by Rotary Swaging: A Review.

Rotary swaging is an industrially applicable intensive plastic deformation method. Due to its versatility, it is popular, especially in the automotive industry. Similar to the well-known methods of severe plastic deformation (SPD), rotary swaging imparts high shear strain into the swaged materials and thus introduces grain refinement down to a very fine, even ultra-fine, level. However, contrary to SPD methods, one of the primary characteristics of which is that they retain the shapes and dimensions of the processed sample, rotary swaging enables the imparting of required shapes and dimensions of workpieces (besides introducing structure refinement and the consequent enhancement of properties and performance). Therefore, under optimized conditions, swaging can be used to process workpieces of virtually any metallic material with theoretically any required dimensions. The main aim of this review is to present the principle of the rotary swaging method and its undeniable advantages. The focus is primarily on assessing its pros and cons by evaluating the imparted microstructures.

Tool wear and its mechanism in turning aluminum alloys with image processing and machine learning methods

Tool wear is intimately related to intelligent operation and maintenance of automated production, workpiece surface quality, dimension accuracy, and tool life. Therefore, it is necessary to improve the production efficiency and quality by predicting tool wear values. The purpose of this research is to use machine learning and image processing methods in estimating the tool wear values when turning AA7075 aluminum alloy. In addition, the in-depth analysis of cutting tools at different parameters were examined with SEM and EDS analysis. The results shown that there was a 44.40% increase in tool wear when the cutting speed was raised by 100% while feed rates were maintained at the same level. On the other hand, there was a 22.78% increase in tool wear seen when the cutting speed was maintained at the same level. In addition, the difference between the actual values and the image processing model is 3.5%, and the difference between the Multilayer Perception (MLP) model and the linear regression (LR) model is 5% and 7%, respectively.

Multi-angle 3D measurement of small workpieces using EDMS algorithm

Binocular vision can get the three-dimensional information of the objects according to two-dimensional images. However, when the background texture information of the workpiece to be measured is weak, or the depth information cannot be recognized due to the change of viewing angle, it will lead to poor three-dimensional measurement accuracy. To address this problem, the paper proposes a multi-view workpiece 3D measurement method based on binocular vision. First, an experimental bench with a Chessboard is designed. The corner point reconstruction is realized by extracting the corner point of the calibration plate. The checkerboard plane is fitted by the least squares method to obtain the checkerboard plane mathematical model. Then, the vertices of the workpiece are extracted at the subpixel level, and a minimum distance sparse vertex stereo matching algorithm (EDMS) based on Euclidean distance metric is proposed to achieve accurate and fast corner matching. Finally, the three-dimensional dimensions of the workpiece are calculated. Through experiments on multiple angles of the two workpieces, the results show that the average absolute error measured by the method at different angles is 0.33 mm, the total relative error is 0.90%, and the variance is less than that 0.01 mm2, realizing the more accurate measurement of multi-view three-dimensional dimensions of small workpieces. This paper provides a new binocular vision handheld mobile 3D measurement equipment method.

Deformation state of the load-bearing structure of a four-column the press

During the operation of each machine, the deformation and stress state of its supporting structure is directly related to the load. The load intensity ranges from the minimum to the maximum value and is a function of nominal force, torque, and kinematic-dynamic values of moving and executive assemblies during the machine operation process. The intensity of deformations is also a function of the shape and type of the supporting structure. However, although the supporting structure is reliable, which refers to its integrity, the production of a quality workpiece (product) does not have to be reliable. Therefore, it is important that the deformation states of the supporting structure be in the appropriate tolerance field, regardless of the intensity of the load. If the intensity of deformations is outside a certain field, it will directly affect the quality of the workpiece that is made on the subject machine. It is known that load-bearing structures can be of open and closed types, load-bearing structures of closed type are used for higher loads and larger workpiece dimensions. By installing sensors on the elements of the supporting structure with accompanying measuring chains in real-time, the deformation state of certain elements or places on the supporting structure can be monitored, based on which the reliable quality of the workpiece can be influenced.

Finite element analysis of material deformation behaviour during DRECE: the sheet metal SPD process

The material deformation behaviour during the innovative SPD process called DRECE (Dual Rolls Equal Channel Extrusion) has been analysed by FEM simulations. In the process, a workpiece in the form of a strip is subjected to plastic deformation by passing through the angular channel; however, the workpiece dimensions remain the same after a pass is finished. Performing consecutive passes allow for increasing the effective strain in the material to a required level. In the conducted simulations two various channel angles (108° and 113°) have been taken into consideration, as well as two processing routes, A and C (without and with turning the strip upside-down between consecutive passes, respectively). The analysis of simulation results has revealed that significant strain and stress inhomogeneities across the strip thickness are generated in a single DRECE pass. The die design (the inner and outer corner radius) and friction conditions affect the material flow, reducing significantly the shear strain in the near-surface regions of the strip. The strain inhomogeneity can be effectively reduced by choosing the processing route C. The strain distributions and the corresponding tensile test results have confirmed that the smaller channel die angle allows to generate larger strain and higher strength of the strip but also reduces its ductility more than the die setup with the larger channel die angle.

Nanoparticle lubricant additives applied in a CNC lathe ball screw component for improving the quality of machined workpieces: A case study

A lathe ball screw is a mechanical actuator that translates rotational motion to linear motion. These machine elements are lubricated to reduce friction and wear since they can affect dimensions of the machined workpiece, measured by Cp and Cpk process capability indicators, and the number of equipment shutdowns. In this work, different nanoparticles (NPs) were added to a commercial lubricant for machine tool slideways with the purpose of reducing coefficient of friction (COF) and wear. NPs of SiO2, CaCO3 and montmorillonite clay (MMT) were added to the lubricant in concentrations on 0.01 and 0.05 wt%. Four ball tests performed under scuffing conditions showed that the best concentration was 0.01 wt% for all NPs, with improvements in load-carrying capacity of 13–15%. Higher concentrations resulted in agglomeration and these large NP clusters were not able to infiltrate the contact area to reduce friction and wear. Block-on-ring tests showed that 0.01 wt% MMT reduced wear and COF by 83% and 81%, respectively. Finally, machining tests were performed in a CNC lathe with the 0.01 wt% MMT nanolubricant for the ball screw component. Improvement was measured by keeping track of the dispersion of the workpiece dimensions, the process capability indicators Cp and Cpk and the number of equipment shutdowns for adjustments. The addition of MMT NPs to the lubricant improved Cp and Cpk by 34% and 52%, indicating a lower variation on the work piece measurements. Furthermore, equipment shutdowns were reduced by up to 50%, improving the process efficiency and lowering manufacturing costs.

A Systematic Review of Factors Affecting the Process Parameters and Various Measurement Techniques in Forging Processes

Forging is a primary manufacturing process used in several manufacturing industries. Aircraft and automobile industries are manufacturing products with high‐dimensional accuracy and quality that are highly precise or near the required shape. Customers require products that are free of cracks and fulfill their functional requirements. This leads to the advancement of the forging process due to its ability to form complicated and intricate shapes. Herein, a detailed review of the aspects of forging is given in which the optimization of factors like preform design, forging conditions, workpiece dimensions, die design, lubricant properties, and thermal treatment parameters are discussed, enhancing the tool life and forging quality of the product. The selection of die‐forging tool material and methods for enhancing the surface quality of forged products are also reviewed. The article also presents methods for measurement of forging quality, tool life, machine effectiveness, forging image acquisition, and forging parameters, which can significantly reduce the risk of error at every step of the forging process. This review serves as a reference for researchers to increase production rate, enhance the effectiveness of measurement system, and improve the quality of forged products with technological advancement.

Dimensional Error Compensation Based on Data-Driven Sliding Mode Terminal Iterative Learning Control for CNC Batch Grinding

Dimensional error of workpiece is an important index that indicts the grinding accuracy of machine tools. Conventional error compensation strategies focus on modeling one or several error factors for a particular CNC machining type, which are time consuming and costly. Based on data-driven sliding mode terminal iterative learning control, a new dimensional error compensation method is proposed in this paper. The compensation algorithm based on an iterative sliding surface and an objective function is established using the terminal experimental data. A modified NC program is fed to the machine tool to push the workpiece dimension towards desired. The theoretical analysis and experimental results show the proposed compensation method can effectively improve the batch grinding accuracy of the machine tool, which shows good perspective in manufacturing industry.

Hot extrusion of high carbon steel cone hollow products

The work is devoted to researching a new method of hot direct-reverse extrusion of hollow conical products from high-carbon steel and determinated parameters for technological design. The considered method makes it possible to obtain in one step hollow products with different wall thickness in height, while the wall thickness in the upper part of the product can be greater than the thickness in the bottom part. The dimensions of the initial workpiece are determined by modeling using the finite element method, which ensures the simultaneous flow of metal in the forward and reverse directions during the process of forming the product, which reduces the deformation force. The use of this method also leads to a decrease in the heating of the deforming tool due to a decrease in the contact area of the deformed workpiece with the tool. The strain rate is determined to ensure the temperature interval of extrusion. The dependencies of the force of extrusion, removal of the punch from the deformed workpiece, pushing the product out of the matrix on the movement of the corresponding tool are established. The final shape and dimensions of the product with the distribution of temperature and deformations were found. For the maximum amount of extrusion force, the distributions of specific forces on the contacting surfaces of the punch, matrix, ejector and stress on the volume of the deformed workpiece were found. According to the obtained data, the technology of direct-reverse extrusion can be developed and implemented on universal press equipment, which has high productivity due to the reduction of the number of stamping steps. The design of the stamp for extruding products of certain sizes with forced cooling of the matrix is given.

Weighted voting ensemble method for predicting workpiece imaging dimensional deviation based on monocular vision systems

Due to the different heights and positions of all kinds of workpieces, the imaging dimension of workpieces in monocular vision systems exists in deviation. To reduce the deviation and improve the accuracy of dimensional measurement, a BRR-SVR-BPNN weighted voting ensemble learning deviation prediction algorithm is proposed. The proposed method combines the probability inference feature of Bayesian Ridge regression (BRR), the maximum interval penalty feature of support vector regression (SVR), and the nonlinear expression feature of the backpropagation neural network (BPNN). And an automatic image processing method based on Halcon is proposed to establish the datasets for the deviation prediction algorithm. The experimental results show that the proposed algorithm has well prediction effect, high robustness, and accuracy on deviation prediction. It can be easily applied to predict the imaging dimension deviation of various workpieces or other similar tasks to improve the accuracy of workpiece dimension measurement in the industrial field.

Binocular visual dimension measurement method for rectangular workpiece with a precise stereoscopic matching algorithm

Binocular vision measurement benefits from high prediction robustness and low structural complexity. However, there are still significant flaws in its accuracy. In this paper, binocular vision measurement of a rectangular workpiece is investigated. A new precise measurement method based on binocular vision is designed to achieve precise measurement of rectangular workpiece dimensions. Firstly, an algorithm for workpiece location based on Zernike moments and corner matching is proposed and employed to precisely locate the workpiece and extract the sub-pixel coordinates of discrete points on an image’s edge. Then, a novel stereoscopic matching algorithm combined with epipolar-geometry and cross-ratio invariance (CMEC) is proposed to improve the accuracy of binocular vision stereoscopic matching. Finally, a projection plane is introduced after the 3D reconstruction of discrete points in the workpiece contours by fitting the plane with least squares. The projection plane limits the coordinate fluctuations of discrete points. Furthermore, the data screening is used to further improve the accuracy of size calculation. The experimental results of the standard checkerboard and actual workpiece show that CMEC’s matching accuracy reached 99%, and the proposed method’s measurement accuracy reached 0.018 mm. This work presents a novel algorithm for stereoscopic matching in binocular vision and machine vision measurement.

Анализ риска возникновения брака, связанного с погрешностью базирования заготовок при установке в призмы

The paper considers issues of assessing the risk of a product defect due to unacceptable errors in positioning surfaces during machining and caused by deviations in the dimensions of workpieces and sample used in setting up the device. Based on analyzing the published studies devoted to the workpiece positioning errors, the need was revealed to expand approaches to determining the risk of product defects by conducting machine experiments to simulate the contact between workpieces and device mounting elements, as well as to consider the joint quality indicators distribution in analyzing the position deviations. The task was set and an example of risk assessment is provided based on analytical calculation of the workpiece limiting positions, as well as the solid-state computer simulation of the technological system elements contact for the case of processing the tee-type part in a CNC milling operation on a machining center with the vertical spindle axis. Based on the results of solving the problem, examples of recommendations are provided for modifying the technological solution aimed at reducing the risk of product defects.

Hot crimping in a special profile matrix of axisymmetric hollow workpieces from high carbon steel

Using the finite element method, mathematical models were created and studies were carried out of direct and reverse methods of hot crimping in a matrix of a special profile of hollow workpieces made of high-carbon steel with a variable wall thickness along the height. A plastic model of metal and cylindrical coordinates are used. By calculation, the shape and dimensions of the initial workpiece for crimping were established, which provided the required dimensions of the product. Before crimping, a part of the billet was heated along the height, which was subject to deformation in the matrix. The use of a matrix of a special profile with a deforming surface made with annular protrusions made it possible to obtain a product in one step due to a decrease in the influence of friction forces during shaping. The deformation rate is determined to comply with the hot deformation mode during the crimping. The dependences of the axial force on the deforming tool on the movement of punches and the distribution of specific forces on the contact surfaces are established. The use of direct crimping leads to a decrease in forces modes and specific forces on the tool. The final stress-strain state of the metal, the shape and dimensions of the product are determined. According to the distribution of strain intensity, an assessment was made of the elaboration of the metal structure by plastic deformation. Based on the simulation data, a design of the general view of the die tooling for direct crimping has been developed.

Numerical Analysis of Translational Vibration Reduction Response on Drilling Process due to Additional Mass-Rubber Dynamic Vibration Absorber (MR-DVA)

Machining is an important part of the industry, one of which is the drilling process. The drilling process is utilized in the making of holes in a material. When the drill-bit touches the material, it causes a vibration that can affect the quality of the hole surface. Therefore, the analysis of the addition of MR-DVA with a natural frequency of 1,630.2 Hz on a workpiece Aluminium Alloy 7075-T6 as the main system is conducted. Simulations were carried out in the natural frequency range of 1,675 Hz – 1,680 Hz with various workpiece dimension ratios of 2⁄5, 3⁄5, 4⁄5, and 5⁄5, along with the different ratios of an MR-DVA placement between the clamp and hole of 1⁄4, 2⁄4, and 3⁄4. Based on the conducted simulation, it has been found that the MR-DVA with a mass ratio of 1⁄20 can dampen well. The largest reduction for a workpiece dimension ratio of 2⁄5 with an MR-DVA placement ratio of 1⁄4 is 92%. In contrast, the smallest reduction for a workpiece dimension ratio of 3⁄5 is 7.2%. These are because the damping area and the increase in the workpiece's dimensions ratio are inverses, affecting the workpiece area that touches the clamp.

Developing an Automated System to Control the Rolled Product Section for a Wire Rod Mill with Multi-Roll Passes

The key priority of metallurgical industry development is expanding the range and improving the quality of bar products and their major component, steel wire. Continuous wire rod mills with multi-roll passes have been developed and implemented over the past decades. These include mills with four-roll passes with mutually perpendicular rolls. The specific feature of mills with complex passes is the impossibility of conduct and the direct measurement of the workpiece dimensions in several directions during rolling. The paper studies the development of a system for indirect control over complex section geometry by adjusting the interstand space tension with simultaneous compensation for changes in rolling forces. The paper contribution is the first justification of a technique for the control over the indirect rolled product section on mills with multi-roll passes based on theoretical and experimental research. Analytical and experimental dependencies between the metal pressure on the rolls and the semifinished rolled product temperature, rolling speed, and single drawing have been obtained for various steel grades. The impact of process factors on the rolled product section geometry when rolling in stands with four-roll passes has first been studied. The automated control system implementing the proposed technique has passed pilot tests on a continuous five-stand mill. The processes occurring in closed-loop speed and torque control systems under controlling and disturbing effects have been experimentally studied. Implementing the proposed algorithms indirectly confirmed the reduced impact of tension and pressure on the section geometry.

STUDY OF THE MOVEMENT OF SOIL PARTICLES ON THE SURFACE OF A SCREW TILLAGE WORKING BODY

This study considers the interaction of soil particles with a screw tillage body, the working surface of which is made in the form of a deployed helicoid and substantially differs from the screw. Furthermore, the unfolded surface is characterised by manufacturability of the working body, since it is possible to calculate the geometric dimensions of a flat workpiece, which is formed into a finished product by simple bending with minimal plastic deformations. The purpose of this paper was to conduct theoretical and experimental studies of the movement of soil particles along the helical surface of the tillage working body, which is made in the form of a deployed helicoid. Mathematical modelling of the processes of movement of soil particles along the helical surface of a tillage working body was described based on general laws and principles of analytical and differential mathematics, theoretical and analytical mechanics. Experimental studies were carried out using a methodology with elements of mathematical statistics, mathematical methods of optimal planning of a multifactor experiment. The analysis of the results of experimental and theoretical studies was performed using applied computer programmes and systems. Experimental studies were conducted according to standard and independently developed methods. Results: a mathematical model of the movement of soil particles along the helical surface of the tillage body was developed, and it was established that when the angle of attack of the helical tillage working body increases, the lifting value of soil particles increases and the area of their dispersion by the helical surface increases. The value of the coefficient of friction does not substantially affect the shape of the trajectory of the soil particle. The quality of loosening the soil most depends on the angle of attack of the screw surface and the angular speed of rotation of the working body. The materials of this paper can be used by scientists for further research and practices in the selection of tillage units.

Adaptive Gaussian Quantum based PSO and TSA optimization for parametric Optimizaiton of Toughned glass on Toughening machine

Usually, toughened glasses are used for safer road transport and general purposes. This is because toughened glasses are difficult to break since these types of glasses are four to five times stronger than ordinary glasses. Meanwhile, the compressive strength of the glass needs to be enhanced and tensile strength needs to be minimized to enhance the toughening glass quality. In addition to this, both cutting and machining parameters need to be optimized and validate with the production rate and the company product thus optimizing the production cost. In this paper, the machining and cutting parameters as well as the production cost are optimized using a novel technique named Adaptive Gaussian Quantum behaved Particle Swarm Optimization algorithm and Tunicate Swarm algorithm (AGQPSOA-TS) approach. Here, two different algorithms namely Adaptive Gaussian Quantum behaved Particle Swarm Optimization algorithm and Tunicate Swarm algorithm are integrated and proposed a novel technique named AGQPSOA-TS algorithm. Finally, the experiments are carried out with the aim of enhancing the compressive strength and minimizing the tensile strength of the toughened glass. According to the Indian standards, the thickness and dimensions of the glass workpiece are taken as 5 mm and 200mmx200mm respectively. The comparative evaluations are conducted for compressive strength, tensile strength as well as production cost to depict the efficiency of the proposed system.

Effect and control of path parameters on thickness distribution of cylindrical cups formed via multi-pass conventional spinning

In this study, an artificial neural network (ANN) model was constructed to investigate the relationship between the roller path parameters to form a cylindrical cup in multi-pass conventional spinning and the thickness distribution throughout the height of a workpiece. Furthermore, the path parameters that simultaneously realize multiple target values of the workpiece dimensions were calculated instantly by the iterative solution based on the constructed model. A systematic design of the path parameters for a constant thickness distribution was established as follows. First, the roller path was expressed using 12 parameters. Second, the workpieces were spun under various experimental conditions, which were determined by partial randomization of the orthogonal array based on the Taguchi method. Third, an ANN model was trained by considering seven path parameters as inputs and five forming result values as outputs (cup height, wall thickness at 25%, 50%, and 75% of the cup height, and residual path length). Finally, the path parameters required for realizing a constant thickness were determined using an ANN model with an iterative solution. Although several samples of the training dataset exhibited non-uniform thickness distributions, the workpieces that were spun under the parameters obtained via iteration exhibited a constant thickness distribution. The parameters responsible for stretching the material in the radial direction significantly affected the thickness distribution. The most influential parameter was the increment in the axial start position for each curved pass.Graphical abstract

Порівняльний аналіз результатів визначення припусків за нормативами та за розрахунково-аналітичним методом з використанням розмірного аналізу технологічних процесів

A comparative analysis of the results of determining the general allowance according to the standards and the allowance determined using the calculation-analytical method on the example of processing by boring the main hole in the workpiece of the body part was performed. The studies were carried out on the example of the technological process of mechanical processing of the workpiece of the "Hull" type part. The determination of technological dimensions and dimensions of the initial workpiece, as well as intermediate allowances and general allowance for all transitions of processing (boring) of one of the main holes is considered. It was believed that the initial workpiece is casting in shell molds. To determine one of the components of the minimum pass, namely the spatial deviations of the surface of the hole relative to technological bases, the dimensional analysis apparatus of the technological process was used, which takes into account the specific conditions of this process, in particular, the peculiarities of the scheme of basing on the first operation. A comparison of the amount of the total minimum allowance determined using the calculation-analytical method with the amount of the total allowance determined according to the normative tables showed that the calculated allowance exceeds the standard by almost 30%, and the most significant influence on the amount of the calculated total allowance is the value of the spatial deviation of the axis of the hole in the initial workpiece relative to the technological bases. Therefore, if the first operation of the technological process solves the problem of ensuring the dimensional relationship between the processed and untreated surfaces, then the allowance determined according to the standards during the processing of a batch of blanks on a set machine may not be enough to ensure the required surface quality details Therefore, in this case, it is necessary to use the calculation and analytical method to determine both the intermediate allowances and the total allowance.