Drawing Force Research Articles

FEM Simulation on First-Step Drawing Process of Platinum-Clad Nickel Bars

The purpose of this study is to investigate the effects of semi-angle and platinum tube wall thicknesses on the first-step drawing process of platinum-clad nickel bars using finite element simulation. Three different semi-angles of die (3°, 5°, 7°) and three different platinum tube wall thicknesses (0.275 mm, 0.3 mm, 0.325 mm) were selected in the study. The effects of semi-angle and platinum tube wall thicknesses on drawing force, equivalent stress, cladding behavior and damage coefficients during the first-step drawing process were discussed in detail. The simulated results of cladding condition and damage obtained from Deform 3D V11 software are validated with experimental results, and it was found that the results were in good agreement. The results of this study may provide a reference for the practical production of platinum-clad nickel wires.

Influence of Strain Hardening Rate of Material on Temperature and Strain Distributions during Wire Drawing.

Temperature rise of a specimen is a significant issue in drawing industries for wire, rod, and bar products, because an excessive increase in temperature during the drawing process can deteriorate the product quality and die life. The influence of the strain hardening exponent (n) of a wire on the temperature and strain distributions during wire drawing is investigated to understand its effect and to improve the quality of drawn wire. Finite element analysis and experiments are conducted to analyze the temperature and strain distributions of wires with n values of 0.0, 0.1, 0.5, and 1.0. The temperature increase of the wire augments as the n of the wire increases, despite the same amount of ideal plastic deformation, which is associated closely with the redundant work. The shear strain increases with the n of the specimen, which generates redundant work, leading to a high temperature rise. Similarly, drawing force increases with the n of the specimen, owing to the increase in redundant work with the n of the wire. In addition, the drawing force presents a linear relationship with the temperature rise of the wire. The drawing speed should be reduced and/or the cooling of wire and die should be strengthened during wire drawing, with increasing n value of the wire, because product quality and die wear are highly associated with the temperature rise of the wire in the deformation zone.

Friction-related size effect during IN718 tube drawing: Realization of ultra-low friction

Drawing process, with the advantages of high accuracy and efficiency, is a common process for tube production. The high friction in tube drawing leads to high drawing forces, easy breakage of tube and high production costs, etc. It is urgent to reduce friction coefficient during the tube drawing. However, the effect of contact area on friction (friction-related size effect) along with the coupling effects of surface roughness, lubricants, and coatings is still unclear or even contradictory, which causes the reduction of the friction coefficient in tube drawing to become a challenge. In this study, taking IN718 tube drawing as the research object, the influence mechanism of contact area (1.25–12.06 mm2) as well as the coupling effects of surface roughness (0.513–0.622 µm), lubrication status, and coatings on friction was explored to reduce the friction coefficient as much as possible. Firstly, a new multi-sensor drawing device is designed to obtain contact pressure and drawing force, combined with finite element model, to characterize friction coefficient during the tube drawing. Secondly, the finite element model considering pits and lubricant is designed to reveal the friction mechanism in tube drawing. The results indicate that as the nominal contact area increases, the proportion of actual contact area decreases, leading to a decrease in friction coefficient, from 0.1102 to 0.0502, a decrease of 54.36%. The reduction of roughness leads to the weakening of plough effect, the coating leads to a transformation of the friction pair, and the lubricant bears some pressure, all of which can lead to a decrease in the friction coefficient, from 0.1203 to 0.0351, a decrease of 70.79%. By designing appropriate contact area (12.06 mm2), surface roughness (0.513 µm), lubrication status (graphite), and coating (sodium fluoride), the friction coefficient is sharply reduced from 0.1203 to 0.0014, a decrease of 98.79%. This in turn leads to a significant increase in the deformation amount, viz., the single pass drawing deformation amount is greatly improved from 14.22% to 49.65%. The research results have significantly reduced production costs.

Simulation of deep drawing of dual phase steel sheets incorporating tribological behaviour predicted by advanced friction modelling

In a deep drawing process, friction at the sheet metal-die contact interface affects the material flow in the flange as well as at the die entry affecting product quality significantly. The accuracy of predicted drawing force and thinning in deep drawing simulation strongly depends on friction modelling. The Coulomb friction model with a constant coefficient of friction is generally assumed in simulations. In reality, the actual friction coefficient depends on process variables such as local contact pressure, relative sliding velocity, and strain in the sheet material. In this work, an approach is presented for deep drawing simulation of dual phase (DP600) steel sheets incorporating the effect of these variables on the friction coefficient. Strip drawing tests under conditions similar to that exist in the flange area during deep drawing have been carried out. Deep drawing simulations have been performed using two friction models taking into consideration the variation of friction coefficient with respect to pressure and velocity. The predicted punch force and thickness variation are validated using deep drawing experiments. A considerable improvement in the accuracy of predicted results has been observed when compared to a constant coefficient of friction.

Influence of TiN Coating on the Drawing Force and Friction Coefficient in the Deep Drawing Process of AlMg4.5Mn0.7 Thin Sheets.

The influence of various process parameters on the deep drawing process is a current research topic in sheet metal forming technology. Starting from the application of the previously constructed original testing device, an original tribological model was developed based on the process of sheet metal strip sliding between flat contact surfaces under variable pressures. A complex experiment was executed using an Al alloy sheet, tool contact surfaces of different roughness, two types of lubricants and variable contact pressures. The procedure included analytically pre-defined contact pressure functions based on which, for each of the mentioned conditions, the dependencies of the drawing forces and friction coefficients were obtained. The pressure in function P1 constantly decreased from a high initial value until the minimum, while in function P3 the pressure increased until the minimum value at the halfway point of the stroke, after which it increased up to the initial value. On the other hand, the pressure in function P2 constantly increased from the initial minimum value until the maximum value, while in function P4 the pressure increased until reaching the maximum value at the halfway point of the stroke, after which it decreased to the minimum value. This enabled the determination of the influence of tribological factors on the process parameters of intensity of traction (deformation force) and coefficient of friction. The pressure functions starting with decreasing trends produced higher values for the traction forces and the friction coefficient. In addition, it was established that the roughness of the contact surfaces of the tool, especially those with titanium nitride coating, has a significant influence on the process parameters. For surfaces of lower roughness (polished), a tendency of the Al thin sheet to form a glued-on layer was noticed. This was especially prominent for lubrication with MoS2-based grease under conditions of high contact pressure (functions P1 and P4 at the beginning of the contact).

Experimental-numerical analysis to determine the efficiency of industrial lubricants in wire drawing process

Drawing is a manufacturing process that consists of indirect deformation by pulling the material through a tool with a conical geometry. The process is usually performed at room temperature (cold forming), so the selection of effective lubricants is critical. If lubrication is inadequate, there is a high risk that both, tool and the manufactured wire, will fail. In this study, annealed AISI 1020 steel rods were drawn and the effectiveness of three different industrial lubricants was tested. During the process, the drawing force values were recorded and used to determine the friction coefficient that developed under each lubrication condition. Numerical simulations were performed to further understand the process. Based on the experimental and numerical results, qualitative and quantitative analysis were performed for each condition. Among the different lubricants used in this study, zinc stearate showed the lowest value for drawing force, 18.8 kN, followed by Lub A and B with values of 20 kN and 20.6 kN, respectively. The numerical models showed excellent approximation to the force values determined in the tests. The values for the coefficient of friction obtained by both the numerical analysis and the empirical model indicate that zinc stearate has the highest lubricating effect among the lubricants focused on this study.

Tribological behaviour of ultra-thin stainless steel in micro deep drawing with graphene nanosheets

In this study, the micro deep drawing (MDD) experiments of an austenitic stainless steel with 40 μm in thickness were conducted using the lubricants containing different mass fractions of graphene nanosheets (GNS) in ethanol. Prior to the MDD tests, the lubricants with GNS concentrations of 5, 10, and 15 mg/ml were synthesised by mixing different amounts of GNS with pure ethanol, and then sprayed uniformly on the blank surface. The friction-reduction mechanisms of the GNS in the MDD were discussed by analysing the profile and surface roughness of the microcups. The results indicated that the GNS could reduce the friction and improve the surface quality of the micro products during the MDD process. In particular, the lubricant with 10 mg/ml GNS enabled the lowest drawing force, wrinkling, and surface roughness of the drawn microcup. These findings contribute to a better understanding of the friction-reduction mechanisms of using GNS in the MDD of materials.

Analysis of The Effect of Ultrasonic Excitation on The Wire Drawing Process for Aluminium Wire Using Finite Element Method

The utilization of aluminium wires is widespread in the electrical energy transmission industry as well as in various other applications. Wire drawing are used to decrease the diameter of the wires. Simulations are conducted utilizing simulation software to imitate the drawing process of a 2.6 mm diameter Aluminium wire and reducing it to 2.2 mm through both conventional drawing methods and simulation that includes excitation of ultrasonic stimulation. The study of adding ultrasonic stimulation focuses on two critical elements, the draw force and its impact on the energy consumption during the drawing process, and the stress induced on the aluminium wire. The results of the simulation demonstrate a reduction in both the energy consumption and the stress levels on the Aluminium wire as a result of incorporating ultrasonic technique in stimulation of the drawing process.

An Upper Bound Solution for Axisymmetric Extrusion and Drawing Considering a Generalized Yield Criterion

The yield criterion of many metallic materials differs from the von Mises yield criterion. However, the available upper bound solutions are almost all restricted to this criterion. The objective of the present paper was to derive an upper bound solution based on a generalized yield criterion for evaluating the extrusion and drawing force, assuming a conical die. The solution method differs from the conventional method used in conjunction with the von Mises yield criterion. The development of this method is necessary, since the work function is not readily expressed as an explicit function of strain rate invariants if the generalized yield criterion is adopted. The solution is illustrated using numerical examples, which show the effect of the yield criterion on the limit load.

Application of shaped tube as preform to eliminate the forming defects of ribbed tube in multi-pass drawing

Thin-walled ribbed tube with small-diameter is a newly designed structure, which is used in nuclear fuel cladding. Due to the high precision requirements of nuclear industry applications, the integral forming and precision forming of ribbed tube are the focus of research. However, the forming defects — rib grooves often fail to achieve the precision forming of ribbed tube. Therefore, the two-pass drawing process is designed to realize the integral forming of ribbed tube and the forming mechanism of ribbed tube is analyzed. Further, the effect of round tube as billet on the forming accuracy of ribbed tube is studied. The results show that the rib groove defects are caused by local large deformation and excessive metal flow, which can not be completely eliminated only by changing the billet size of round tube. Based on this, three kinds of shaped tubes as preforms instead of round billet are proposed for eliminating the rib groove defects to realize the precision forming of ribbed tube. The effects of different preform schemes on the forming accuracy, drawing force and stress distribution of ribbed tube are compared and discussed. By selecting the optimal preform scheme and applying it to multi-pass drawing, the completely defect-free ribbed tube is obtained. At the same time, after adopting the appropriate billet size, the rib filling fullness of the tube is further improved and closer to the target size. Moreover, the microstructure of ribbed tube after multi-pass drawing are observed. The martensite and deformation twins appeared due to work hardening and the grain size refinement degree of different positions are different due to different deformation degree.

Analysis of TiO2 Nanolubricant Influence in Micro Deep Drawing of Stainless Steel SUS301

To improve the quality of products produced from microforming, various nanolubricants have been applied in the field of micromanufacturing in recent years. In this paper, the effects of glycerol-based lubricant containing TiO2 NPs (NPs) on micro deep drawing (MDD) of austenitic stainless steel (ASS) SUS301 were studied, and the lubrication mechanism involved was discussed. The MDD experiments were conducted with the SUS301 foils under dry, 1, 2, and 4 wt% TiO2 NP lubrication conditions. The results show that the use of the TiO2 nanolubricants can significantly improve the quality of the drawn cups in terms of decreased wrinkling and surface roughness. Besides, the concentration of TiO2 NPs influences lubricity by reducing friction during the MDD process. The peak drawing force is the lowest when 2 wt% nanolubricant is applied, which drops to 72.54 N from 77.38 N under dry conditions. The micro cup drawn under 2 wt% TiO2 nanolubricant has the best quality among those obtained under all the lubrication conditions. The lubrication mechanisms are derived from the mending effects of TiO2 NPs and the formation of thin lubricant films associated with the open lubricant pockets (OLPs) and close lubricant pocket (CLPs) theory in the MDD. The CLPs function as reservoirs that retain lubricants to counteract the load pressure, whereas the OLPs lead to lubricant leakage due to the higher flow resistance. It was found that the lubricant film and NPs are insufficient at a low concentration (1 wt%), while the lubrication performance can be enhanced with increased NP concentration. However, there exist apparent agglomerations on the surface of the produced micro cup when using 4 wt% nanolubricant, which greatly deteriorates the lubricant performance in the MDD process. It is concluded that the lubricant containing 2 wt% TiO2 NPs demonstrates the best lubrication performance during the MDD of ASS SUS301.

Cold Microdrawing of Pure Magnesium Capillary Structures for Biomedical Applications

Abstract This paper presents a study on cold microdrawing of pure magnesium for biomedical applications, where hollow sinking drawing of microtubes of 820 μm diameter and wall thickness around 100 μm was used, varying drawing speeds to achieve a significant reduction in cross-sectional area in a single pass. Results showed an improved surface finish with reduced surface roughness after drawing. The material exhibited an increase in microhardness and ultimate tensile strength by 41% due to work hardening caused by plastic deformation. The study also identified wall thickening of the tube and observed springback behavior of Mg at the die exit. Drawing forces were collected for process monitoring, and finite element (FE) simulations were conducted to assess the risk of pure Mg microtube breakage. This research contributes to advancing the state of the art in Mg microtube drawing, addressing the unique challenge of working with such small tube dimensions where limited studies currently exist.

Experimental Determination and Calculation of the Wire Drawing Force in Monolithic Dies on Straight-Line Drawing Machines

In this article, a mathematical model has been developed for calculating the energy-power parameters of the drawing process in monolithic dies on straight-line drawing machines, and its adequacy has been validated in experimental wire drawing on a laboratory automated drawing machine. The program allows us to calculate drawing stress, drawing force, tensile strength and yield strength of the alloy after wire drawing, safety factor, and drawing power. The developed mathematical model differs in that it allows us to evaluate the uniformity of deformation over the wire section, depending on the technological parameters of the deformation zone, namely, the semi-angular die, the coefficient of friction and the degree of deformation. To select the technological parameters of the deformation zone, which ensure uniform deformation over the wire cross-section, a nomogram was compiled. The equations of hardening during nickel NP2 wire drawing are obtained. The calculation of energy-power parameters of drawing nickel NP2 (Ni 99.6) wire ∅1.8 mm from ∅4.94 mm wire rod is given. Experimental studies have been carried out to determine the energy-power parameters of nickel wire drawing on a laboratory drawing machine with an installed ring strain gauge to determine the drawing force. A change in the friction coefficient by 0.02 when drawing nickel wire leads to an increase in stress and drawing force by 20%. To improve the accuracy of the developed mathematical model, it is shown that in the future, it would be necessary to conduct experimental studies on a laboratory drawing machine to determine the effect on the energy-power parameters of the drawing process of the values of technological parameters entered into the program as constant real values, such as the friction coefficient, die half-angle, drawing speed, and back tension.

Analyzing the influence of lifter design and ball mill speed on grinding performance, particle behavior and contact forces

Ball mills are the foremost equipment used for grinding in the mineral processing sector. Lifters are placed on the internal walls of the mill and are designed to lift the grinding media (balls) to a higher position. In the calculation of energy consumption in ball mills, classical theories mainly consider factors like the charge fill level, lifter dimensions, the number of lifters, and the rotational speed of the mill. This research recognizes the significance of lifter geometry and proposes a new lifter design aimed at optimizing the energy consumption and efficiency of ball mills. Simulation results by discrete elements obtained in this study were validated using experimental results. By conducting this comparative analysis, the aims of the study was to examine the impact of the new lifter's geometry and rotational speed of the mill on torque, power draw, particles behavior, and contact forces. The findings indicate that when the pitch of the lifters is increased, there is a reduction of 3.30% in torque and power consumption. Additionally, this change leads to an increase in the number of cataracting particles and a 6 to 7% increase in contact forces compared to lifters with a straight shape.

Relative Position of Plug and Die on Forming Accuracy of Shaped Tube by Cold Drawing

In the actual industrial production and manufacturing, tube drawing plays an extremely important role. In this study, a device with adjustable relative plug position is designed, the influence of relative plug position on the dimensional accuracy and the drawing force of drawn tube was investigated. The results show that different relative plug positions affect the inner and outer surface dimensions of the tube respectively. Therefore, the relative plug position can be distinguished according to the following rules in industrial production. When the position of the plug relative to the die is backward, the outer surface dimension of the drawn tube is qualified but the inner surface dimension is unqualified. When the position of the plug relative to the die is forward, the inner surface dimension of the drawn tube is qualified but the outer surface dimension is unqualified. The relative position of the plug is mainly due to the different radial force given to the tube by the plug and the die, resulting in the unqualified size of the drawn tube. When the plug is positioned backward relative to the die, the tube is subjected to the radial force of the plug first and then the radial force of the die. When the plug is positioned forward relative to the die, the tube is subjected to the radial force of the die first and then the radial force of the plug.

UNCONVENTIONAL METHODS OF MANUFACTURING THIN WIRES FOR APPLICATION AS INPUT MATERIAL IN ADDITIVE MANUFACTURING. PART 1: PREPARATION OF INPUT MATERIAL FOR WIRE DRAWING

Part 1 of the article presents the technological path of producing semi-finished products for wires constituting input material in additive technologies. On the basis of the developed chemical compositions of experimental Fe-based alloys, laboratory ingots with a square section of 120×120 mm / 130×130 mm were produced, which were then hot rolled into flat bars. In order to select the physical parameters of the drawing tests, numerical modelling of the process was performed. As a result of the simulations, it was found that the calculated drawing force exceeds the capabilities of the experimental drawing machine and for this reason, hydrostatic extrusion was used to produce bars intended for drawing wires. The hydrostatic extrusion method was used to make bars with a diameter of 5 mm from three tested materials, while three experimental steels showed insufficient susceptibility to extrusion at high pressure and cracked at various strain values. An analysis of possible causes of bar breakage during extrusion was carried out on the basis of the results of microstructure examination.

Effect of Forming Method on the Behavior of the Drawing Process of a Complex Shape

This paper aims to produce a complex shape with eight vertices in a deep-drawing process. Two methods were used to perform this study. The first method is called the direct method (drawing process), in which a complex shape was produced directly from drawing metal sheets. The second method called the indirect method (redrawing process) involves producing a complex shape from the re-drawing process of the cylindrical shape previously drawn from sheet metal. The two methods were also compared in terms of drawing force, thickness distribution, stress, and strain distribution. The sheet metal used in this work is made of low carbon steel (1008-AISI) with dimensions of 0.7 mm in thickness and 80 mm in diameter. In the present study, ANSYS 18.0 software was used for simulating the drawing and redrawing process. The results indicate the maximum drawing force with a drawing process (41 KN EXP, 30 KN FES). The effective stress and the effective strain increase until the cup’s end and reach the maximum values of the effective stress (835.23 MPa FES) and the effective strain (0. 442 FES, 0.345 EXP) in the area of the minor axis curvature with the process of re-drawing. The maximum thinning at the corner area with the redrawing process (7. 143% FES, 5.722% EXP) at the zone of the minor axis curvature. Also, the best distribution of thickness, stresses, and strains along the wall of the complex shape with the first method (drawing process).

Comparison of Clinical and Radiographic Outcomes According to the Presence or Absence of a Posterior Draw Force during Graft Fixation in Anterior Cruciate Ligament Reconstruction.

Background and Objectives: A reduction forced toward the posterior side during graft fixation may help to lessen anterior tibial translation after ACL reconstruction. The purpose was to compare the clinical and radiological outcomes of graft fixation when a posterior draw was used and when it was not used during anterior cruciate ligament (ACL) reconstruction surgery. Materials and Methods: Of 110 patients who had undergone primary arthroscopic ACL reconstruction between January 2017 and August 2020, in all, 76 patients had been operated on without a posterior draw (non-draw group), and 34 patients had received surgery with a posterior draw (draw group). The results of the Lachman test and the pivot-shift test, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) indexes, the Lysholm scores, the International Knee Documentation Committee (IKDC) subjective scores, and side-to-side difference (STSD) on stress radiography were compared between the two groups. Results: The postoperative WOMAC indexes, Lysholm scores, and IKDC subjective scores were similar across both groups. Postoperative STSD (2.4 ± 2.2 for the non-draw group vs. 2.0 ± 2.2 for the draw group; p = 0.319) and change in STSD (3.5 ± 3.5 for preoperative STSD vs. 4.3 ± 4.4 for postoperative STSD; p = 0.295) were not superior in the draw group. Conclusions: The take-home message is that graft fixation with a posterior draw during ACL reconstruction did not result in significantly better postoperative stability. The postoperative clinical outcomes were similar between both groups.

Optimization of wire drawing process in terms of rheological characteristics of stretching material and refinement of die hole geometry

The article discusses the improvement of the analytical method for calculating the wire drawing force, taking into account the rheological properties of the material being pulled and clarifying the geometry of the die hole, provides a new analytical model for calculating the drawing force, describes the algorithm for calculating the drawing force, analyzes the results of modeling the drawing process for round products.

Coaxial mechano‐electrospinning of oriented fibers with core‐shell structure for tactile sensing

AbstractCoaxial electrospinning is an effective technique to produce core‐shell fibers. Nevertheless, it is unable to realize accurate positioning of the fibers in two dimensions which limits its use in the field of high oriented and aligned structures over large area such as flexible tactile sensors. Here, we introduce the Mechano‐electrospinning, in which drawing force coming from moving substrate and electric static force are used to manipulate the fiber controllable into the traditional coaxial electrospinning to form a new method named coaxial Mechano‐electrospinning which can continuously direct‐write oriented core‐shell fiber with high deposition accuracy. This method uses a coaxial convex needle and a two dimensional moving collector to deposit core‐shell fibers by near‐field localization and mechanical drawing force. A series of experiments were performed to determine optimum process parameters and results showed that with the substrate moving speed of 50–200 mm/s, voltage of 5–6.5 kV and the tip‐collector distance of 20–50 mm, core‐shell fibers can be continuously deposited and well oriented. Additionally, a pressure sensor based on the core‐shell fibers was developed and exhibited good dynamic sensitivity in the range of 0.5–50 Hz.