Drawing Operation Research Articles

New Physical Scaling Approach to compensate the part contraction in drawing operations

Further increasing requirements to the quality of car body components represent a huge challenge for the process planner. Springback effects are causing dimensional deviations of the car body components from their respective target geometry. Both elastic membrane and bending stresses result in global and regional distortions and deflections. In addition to these effects in particular the membrane stresses furthermore result in a contraction of the drawshell with the effect that the drawshell is smaller than the tool after drawing. In order to compensate this contraction the drawing tool has to be increased. This process is known as the so-called scaling. An appropriate scaling should result in a contracted part which has the same surface area and unwound lengths as the target geometry. In case of deviations of the unwound lengths unwanted plastic deformations of the part in subsequent operations have to be expected and the part’s assembly dimensions will differ from the target geometry which can cause significant quality issues in the car body. Today the scaling is usually done by increasing the tool with a unique global scaling factor or with different scaling factors for different directions. However, since the contraction varies along the part surface in reality the results are only suboptimal. Here a new scaling approach is being presented which uses the simulation results to scale the tool surfaces locally. By doing so the locally different contractions can be better compensated.

Influence of a drawbead passage in deep drawing processes on surface values and the tribological system

In recent times, lightweight design and functional integration in metal forming and especially in deep drawing operations lead to complex geometries. These geometries can cause variable defects in production. Especially with modern materials like AHSS or UHSS, deep drawing becomes more challenging. One common way to meet these challenges and manufacture sheet metal parts without defects is the application of drawbeads in the forming tool. Drawbeads are used for an exact control and forecast of the material flow during the deep drawing process. It was already shown, that different material parameters like the tensile strength and the fracture strain are changed significantly after running through a drawbead. In addition, there are various indications that the tribological system in a drawbead passage is also changed significantly and that this has further influence on the ongoing drawing process.This assumption is examined with an experimental setup derived from industrial deep drawing processes. Therefore, different sheet metal materials are drawn through a drawbead geometry under the same conditions like the blank holder force, the drawing velocity or lubrication. After the drawbead passage, 3D surface parameters are measured and compared to the values in its initial state. Following, conventional strip-drawing tests with preloaded strips are carried out. The variation of the friction coefficient after a drawbead passage is analysed and compared to the initial state. The results are correlated with the surface values. For these investigations, three different materials are used: a conventional deep drawing steel because of its wide application as well as an advanced high strength steel AHSS and an aluminium alloy of the 6xxx series as representatives for modern lightweight materials.

Experimental Investigation of Multi-stage Deep Drawing of IN718 Sheet at Elevated Temperature

IN718 is a nickel-based super alloy that retains its mechanical properties at elevated temperatures and hence has numerous applications in the aerospace industry. In this study, deep drawing of IN718 sheet at elevated temperatures (700-1000°C) has been investigated experimentally. Initially, stress-strain response with failure strain at different temperatures was evaluated by uniaxial tensile tests along different orientations. Subsequently, hot deep drawing and re-drawing tools were designed and fabricated. A circle-grid marked circular blank of 3mm thickness was used in the first draw to form a circular cup followed by re-drawing (2nd draw). The major and minor diameter of the circular grid on the blank after the deep drawing was used to examine the strain distribution in the drawn cup and further used to calculate the thickness strain. These deep drawing operations were carried out at different temperatures with a constant blank holding force. Further, the deep drawing force at different temperatures was examined. The effect of the test temperatures during hot deep drawing and the process parameters on the variation of the thickness strain over the surface of the drawn cup has been studied. Finally, the major and minor strains are plotted in Keeler and Arcelor V9 forming limit curve to examine the formability of IN718 sheets at elevated temperature.

Numerical and Experimental Explorations for the Formability of Drawing Square Cups Through Deep Drawing Operation (January 2020)

This study aims to examine the formability of drawing cups having square shapes through direct deep drawing process on a single action press through one pass. This can be accomplished by conducting an FE simulation and performing an experimental investigation on steel substrate type AISI 1008 blank with diameter and thickness dimensions 80, 0.5 mm respectively. To explore and analyze the formability of such a drawing process, two process parameters have been included in this work which is the speed of punch (30 and 300 mm/min) and the lubrication state (with machine oil and dry drawing). Both direct and indirect measurements of thickness strain have been adopted as an indicator of the sheet formability. The results of both FE simulation and experimental work demonstrate that the square drawing of the AISI sheet has been accomplished for all the four cups produced since the highest thinning over the cup wall does not exceed 25% of the original thickness. Generally, there is a good match between the experimental values of the indirect method and the FEM results for all models such that the largest deviation is about 25%. The direct method of thickness measurement is determined to be non-confident as strain values are practically unacceptable. Additionally, higher formability of the sheet has been realized at lower punch speeds. Furthermore, no significant difference has been observed in the formability at both speeds of punch when using a lubricant compared to the dry drawing operation.

Metallurgical investigation of welding wire rod grade during processing

The research work provides an intensive analysis of premature failure of the wires during cold drawing operations. The steel wires are made of WR3M grade, which contains low carbon (0.06–0.08 wt%) with high ‘Mn’ (1.40–1.50 wt%) and ‘Si’ (0.80–1.00 wt%). It is a premium low carbon electrode grade, which can produce superior quality welds and trouble-free performance during different continuous welding process. This welding grade is manufactured from continuous cast billet of dimension 150 mm × 150 mm and then hot rolled through successive rolls to achieve desired dimension. Present work includes microstructural and different thermo-mechanical study to determine the origin of premature failures of wires. Investigation suggested that wire breakage took place due to the presence of light brown hard phase (martensite) which makes the material brittle and initiate chevron cracks during drawing operations. X-ray mapping doesn’t provide any segregation along or near the light brown hard phase. From different plant trials and thermo-mechanical study, it reveals that the light brown hard phase formed due to incomplete transformation of wire rods during retarded cooling process at hot rolling stage.

Experimental Studies on the Stress-Strain State under Drawing Aluminum–Copper Bimetal Parts Rectangular in Plan

The stress-strain state has been studied for a flange of a semiproduct made of an aluminum–copper bimetal under drawing boxes rectangular in plan. These studies are carried out using a grid method, assuming that the material is isotropic and incompressible; the deformation within each cell is uniform; the deformation occurs monotonically; and the stressed state is plane and the deformed state is bulk, but the elastic deformations are negligible. In order to minimize the measurement errors of coordinate grids and reduce the time required for processing information, a CAD software package is used for simulation The billets are rectangles with explosion-welded A4 aluminum and a M4 copper layers subjected to preliminary heat treatment before the operation of drawing. The rectangular billets have been successively drawn to a height of 10 mm; after drawing, the grid and the thickness of the sample under study are measured. The samples of billets have been photographed at an identical focal length and loaded into the application program. In the program, coordinate points are applied to the grid nodes to measure the distances and coordinates of these points before and after deformation. The measurement results show that the greatest deformation is experienced by the corner zones of the billet, where the compressive stresses exhibit an increase from the angle bisector to the walls. These stresses lead to bimetallic billet delamination, as well as to occurring corrugations throughout the copper layer. The drawing is performed for 20 billets and, in each case, the corrugation on the flange surface is observed. Varying the clamping pressure in the range from 0.25 to 0.5 MPa does not lead to any positive results. The end part of the box flange experiences the greatest strain rate, whereas, when approaching the matrix hole, the strain rate exhibits a 20% decrease. The action of angular shear stresses leads to transition-zone discontinuity, which is characterized by the presence of an intermetallic layer having reduced plastic properties.

Dazzle and the origins of drawing

The subject of the study is the problem of drawing in the philosophy of Jacques Derrida and, in particular, the so-called "blindness hypothesis", which Derrida expresses in the work "Memoirs of a blind man: self-portrait and other ruins": "drawing ... and the drawing operation must have some relation to blindness." Derrida explores this well—established ontotheological tradition of classical metaphysics: blinding here becomes a necessary sacrificial act, a condition that makes possible the transition from the physical eye to the spiritual, so Derrida describes it as a "sacrificial" economy, which is inevitably followed by an artist, each drawing of which turns out to be a prophecy of a blind man, indicating the horizons of the future.  Explicating Derrida's hypothesis, we turn not only directly to the text of the "Memoirs of a Blind Man" and the documentary narrative film that accompanied it, but also strive to reconstruct the exhibition of the same name held at the Louvre in 1990, which was also curated by Derrida. The comparison of these three layers made it possible to more fully reveal the "blindness hypothesis" and fit it into a more general philosophical context of deconstruction, as well as to rethink the problems of figurative drawing, its mimetic and representative nature. We come to the conclusion that the essence of the drawing has nothing to do with the visible, and its source lies entirely at the level of memory.

Experimental research of the stress-strain state when drawing aluminum-copper bimetal parts rectangular in plan

The stress-strain state of the aluminum-copper bimetal blank flange was studied when extracting boxes rectangular in plan. The studies were carried out using the grid method with assumptions about the material isotropy and incompressibility; uniform deformation within each cell; monotonous deformation, plane stress and three-dimensional strain state, while elastic strains were neglected. A CAD modeling program was used to minimize coordinate grid measurement errors and reduce the time for processing the information obtained. The blanks were rectangles of certain sizes with an explosion-welded AD aluminum and M4 copper layers subjected to preliminary heat treatment before the drawing operation. Rectangular blanks were successively drawn to a height of 10 mm with grid and test sample thickness measurements after drawing. Blank samples were photographed with the same focal length and loaded into the application program. In the program, coordinate points were applied to grid nodes with the distances and coordinates of these points measured before and after strain. According to measurement results, the highest strain was observed in the blank corner areas where compressive stresses increased from the angle bisector to the walls. These stresses led to bimetallic blank stratification and corrugations formed along the copper layer. 20 blanks were drawn, and corrugation was observed on the flange in each case. Varying the hold-down pressure from 0.25 to 0.5 MPa gave no positive results. The highest strain intensity is observed at the end part of the box flange, and this value decreases by 20 % at the approach to the die hole. The effect of angular shear stresses leads to a discontinuity in the transition zone featuring by the presence of an intermetallic layer with reduced plastic properties.

Trajectory coordination for a cooperative multi-manipulator system and dynamic simulation error analysis

To achieve temporal and spatial correspondence between multiple robotic manipulators, the system must correctly analyze the coordinated path required for a specific task. Based on manipulator kinematics analysis, we first studied the kinematic constraints between the end-effectors of cooperative manipulators, and deduced the multi-manipulator cooperative kinematics constraint equations in the Cartesian coordinate system space under different motion modes. Then, we created two MD-6 manipulator models to simulate the trajectory simulation of the synchronous and relative motion of the manipulator. This allowed us to verify the correctness of the proposed trajectory coordination method, and analyze the influence of external loads on the position and posture of the end-effector of the manipulator, to effectively predict the cooperative motion error of the manipulator system. Finally, in order to verify the effectiveness of the proposed trajectory coordination method, we established a robotic experimental platform and conducted experimental research. The results show that the multi-manipulator trajectory coordination method studied in this paper can make multi-manipulators effectively achieve the target requirements of tasks such as time and space cooperative handling and circular drawing operations.

Design and Fabrication of Drawing Die for Fly Press

Press working is defined as a non -chip removal manufacturing process by which various components are made from sheet metal. There are various types of components are produced from sheet metal operation. The main aim of this project is to "Design and fabrication of drawing die used in the fly press”. The design aspects of drawing die is accomplished in CATIA v5 and ansys 15.0 software. As coming to the manufacturing of drawing die, drawing die are manufactured in hot-chamber process which has the capacity to cast high melting point materials. The press tool leads to different operations namely blanking, drawing, trimming, bending, lancing, perforating, curling and shaving operations. Generally, drawing operation is the process of producing cylindrical objects. There is a vast use of press tools in industries like defense, textile, automobile, aircraft and food processing. The press machine is of the hand-operated fly press.

Analysis of the Drawing Process of Small-Sized Seam Tubes

This article is focused on an analysis of factors negatively affecting the tube production process of tubes made from austenitic stainless steel with a very small diameter of ϕ 0.34 mm. The analysis was concentrated on factors that affect the drawing process stability of the seam tubes where the desired final dimensions—a diameter of ϕ 0.34 mm and a wall thickness of 0.057 mm—are limiting factors. Seam tubes made from steel 1.4306 and 1.4301, from producers KT and EW with a longitudinal weld line made by tungsten inert gas (TIG) welding, were used as blanks for constituent drawing operations. It is desirable to provide sufficient inert gas flow and cooling during the formation of a weld joint in a protective atmosphere chamber. A significant temperature gradient prevents the formation of undesirable Cr23C6 carbides in the heat-affected zone (HAZ) which negatively affects the plasticity and formability of the steel and is the cause of technological fractures.

Lessons from the Experience in Wuhan to Reduce Risk of COVID-19 Infection in Patients Undergoing Long-Term Hemodialysis.

Since December 2019, an outbreak of new coronavirus disease (coronavirus disease 2019 [COVID-19]) has developed into a world pandemic ([1][1]). The city of Wuhan in China, as one of the most seriously affected areas, is now out of the woods ([2][2]), and the aggressive quarantine performed by the

Analytical, numerical, and experimental investigation of the influence of lubrication on the drawing behavior of copper alloy

Environmentally friendly products are increasing demand and the challenge is to combine them with optimal efficiency in industrial processes. In cold drawing, lubrication improves the surface and dimensional quality of the workpiece, reduce tool wear, work loads, and maintenance intervention. Ester-based, vegetable-derived lubricants have interesting properties, such as biodegradability and low toxicity, but their application in forming processes has not yet been investigated despite their use in machining operations. In this work, we evaluated the drawing strength , surface roughness, and microhardness of electrolytic copper in the dry (non-lubricated) condition and using three different types of lubrication: powdered graphite, molybdenum sulfide grease, and ester-based oil, a possible environmentally friendly lubrication substitute for petroleum-derived lubricants. The drawing strength proved to be 23.4% lower when using grease and ester-based oil compared to the dry process, and the grease and ester-based oil presented the same result regarding process performance and material characteristics. Thus, combined with the fact that the ester-based oil led to the lowest friction coefficient between cooper and tool steel among the tested lubricants, it was possible to demonstrate that it can be used as an alternative to conventional products in cold- drawing operations of the tested cooper alloy.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Parametric optimization of the generation of the porous layer for lubrication in tube drawing process

For severe metal deformation processes such as metal drawing operations, the use of porous lubricant carrier layer on metal surfaces has been proposed in recent literature for better lubricant retention and effectiveness under extreme conditions. The porous layer may be generated by different methods and the method chosen in this study involves electroplating a thin layer of an alloy of tin and zinc on the parent metal and subsequent selective etching of zinc. The aim of this study is to optimize parameters for specific application of the new technique in steel tube drawing operation using Taguchi's experimental design procedures. Experiments are designed based on three controllable factors namely electric current density, process time and Sn-Zn composition by weight in electrolyte at three levels. L9 orthogonal array is used for this study. The regression models have been constructed for drawing force and surface roughness along with verification of the model fit using (R2) values and analysis of variance (ANOVA). The optimal values for parameters have been identified using signal to noise (S/N) ratio. All the calculations are obtained by using Minitab software. The optimal levels for: current density (I) is 1 A/cm2; for plating time (T) is 12 min and; Sn:Zn composition is 1:6. This study may pave the way for industrial adoption of the new technique of using porous layer in tube drawing operations to bring out the associated benefits of doing away with the conventional lubrication systems that have proven environmental hazards.

Comparison of numerical simulation results of sheet metal parts’ production for AutoForm and TriboForm friction models

The results of numerical simulations with two friction models are studied. The fi rst model corresponded the Coulomb friction model and used in AutoForm on default. The second friction model took into account the quality of surface treatment, its roughness and amount of the lubricant and the effect of the asperities’ height evolution. It is used in TriboForm. The results obtained for the second friction model are used to simulate sheet metal forming processes in AutoForm. It is found that the TriboForm friction model affected the results of the drawing operation. The difference in the results increased due to bigger deformation values of the technological operation.

Deformation behaviour during deep drawing operation under simple loading path: A simulation study

Deep drawing is a significant metal forming process which is used in sheet metal forming operations. By this process complex shapes can be manufactured with significant accuracy. In this study, the prediction of deformation behaviour of aluminium alloy during an axi-symmetric cup drawing operation is studied numerically. For this purpose, 3D Finite Element (FE) simulation of a simple cup drawing process has been conducted using ABAQUS software. The simulation is done by considering the isotropic hardening and von Mises stress criteria. As the deep drawing process commences, the variation of generated von Misses stresses and plastic equivalent strain are observed at different stages of deformation and the change in strain energy generation of aluminium alloy sheet have been analyzed.

Tribological Effects in Deep Drawing Operation of SUS304 BA Stainless Steel Sheet

Tribological Effects in Deep Drawing Operation of SUS304 BA Stainless Steel Sheet

An Investigation of the Deep Drawing Behavior of Automotive Aluminum Alloys at Very Low Temperatures

Sheet metal aluminum alloys in the 5000 and 6000 series show increased formability if deformed at sub-zero temperatures which is beneficial for processing industries using sheet metals where evermore highly complex-shaped components are produced. In order to evaluate a cryogenic forming process, the temperature-dependent forming limits of the selected materials need to be known. For this determination, a device has been developed which allows deep drawing operations with circular specimens at cryogenic temperatures. The limiting drawing ratio (LDR) of the commercial aluminum alloys EN AW-5182 and EN AW-6016 are investigated in a temperature range from 298 K to 77 K. It is shown that the deep drawing behavior of both materials is generally enhanced at very low temperatures, although the LDR of the EN AW-6016 alloy increases only at temperatures T ≤ 77 K. Furthermore, using mathematical formulations and numerical (finite element) simulations the influence of friction on the punch forces could be predicted. The calculated results and experimental data are compared, and then subsequently discussed.

Comparison of the Mechanical Properties and Forming Behavior of Two Texture-Weakened Mg-Sheet Alloys Produced by Twin Roll Casting

The influence of rolling and annealing on the resulting mechanical properties and forming behavior of Mg-Zn-RE and Mg-Zn-Ca alloys produced via twin roll casting is investigated. After hot rolling followed by an annealing treatment, both alloys develop a fine-grained microstructure with average grain sizes less than 10 µm. A distinctive development of a texture with a pronounced split of the basal poles in the transverse direction, so called TD-split, is observed in both alloys during the annealing. Due to the fine microstructure and weak texture, which enhances the activation of basal slip, both alloys show large ductility with fracture strain higher than 30%. However, due to the TD-split texture, a high asymmetry of the yield stress is observed, where the yield stress in rolling direction is significantly higher than the yield stress along 45° and the transverse direction. Both alloys show high stretch formability at room temperature with Erichsen indices around 7. Despite a low planar anisotropy and high stretch formability, the Mg-Zn-RE alloy shows undesirable earing behavior, while the Mg-Zn-Ca alloy fractures during warm deep drawing. Moreover, the deep drawing operation using the as-rolled sheet of Mg-Zn-RE alloy can be successfully done. It is observed that the earing behavior can be effectively reduced by deviating from the TD-split texture. In this regard, cold rolling was explored to reduce the anisotropy of the ductile and formable alloy.