Cup Wall Thickness Research Articles

Application of multi draw radius deep draw die for increase in formability of redrawn cylindrical cups

Currently, deep drawing and redrawing are the primary methods used to create beverage cans. Research to increase the efficiency of this procedure is ongoing. This study aimed to improve the formability of redrawn cups by proposing a new technique, wherein a multi-die radius (MDR) die was used as a deep drawing die for producing deep-drawn cups and then redrawn once more to create the redrawn cup. It was found that a more uniformly deformed grain microstructure evolutions and cup wall thickness around the cup were achieved in the case of the MDR deep-drawing process compared with the conventional deep-drawing process. However, using the MDR deep-drawn cups to fabricate redrawn cup, the formability in terms of LDR could not be increased. However the formability in terms of cup wall thickness can be significantly increased by approximately 7% thicker.

Improving parameters for achieving uniform cylindrical cup wall thickness in two-step deep drawing processes with SPCC sheet material

Deep drawing processes are essential in modern manufacturing for creating intricate components with deep hollows, particularly cylindrical forms. These processes are widely used in industries such as household appliances, automotive manufacturing, aerospace engineering, and fire safety equipment. This study focuses on the two-step deep drawing of cylindrical cups, utilizing both simulation and experimental methods. The primary goal is to determine optimal geometric and technological parameters for mold design and to address issues like wrinkling and tearing. Key parameters, including punch nose radius (Rpf), die nose radius (Rdf), punch-die clearance (Wf), and blank holder force (BHF), are systematically analyzed. Results show that proper parameters lead to a uniform wall thickness, with deviations reduced to 4.77%. Conversely, improper parameters result in a 12.03% deviation. Improved parameters in the second-step deep drawing yield cylindrical cups that closely match experimental outcomes, free from wrinkling or rim cracking. This research highlights the importance of selecting appropriate parameters to avoid defects.

Investigation of Sheet Thickness and Punch Force in Die Surface Angled Hydro-mechanical Deep Drawing Method

In this study, the effect of die surface angled hydro-mechanical deep drawing method (HMDDM) on sheet metal cup wall thickness and punch force was investigated as experimental and numerical analysis. In the works, 0.9 mm thick DIN EN 10130-1999 sheet metal material was used. The effect of variables on the test results was investigated by using die surface/blank holder angle, punch nose radius, die shoulder radius, chamber pressure and blank holder force as experimental parameters. Numerical analysis experiments were carried out using ANSYS 15.0 package program. Besides, experiments were performed according to the Taguchi experiment plan and L18 orthogonal array. The obtained data were analysed statistically by ANOVA analysis of variance in MINITAB 17.0 package program, and the effect of each parameter on the results was determined as a percentage. As a result, it was determined that the thinning was approximately 15% at most and the thickening was 10%.

Improved uniformity in cylindrical cup wall thickness at elevated temperatures using deep drawing process for SPCC sheet steel

Improved uniformity in cylindrical cup wall thickness at elevated temperatures using deep drawing process for SPCC sheet steel

How screw connections influence the primary stability of acetabular cups under consideration of different bone models

IntroductionGood osteointegration of implants requires sufficient primary stability. Aim of this study was to examine the influence of screw fixation on the primary stability of press-fit cups. MethodsTwo press-fit acetabular cups were tested with regard to the influence and number of screws and their primary stability. ResultsFor the relatively thin-walled Allofit®-S cup, an influence of the number of screws on the different forms of movement could be demonstrated. ConclusionsWe see a clear influence of the cup wall thickness on the elastic deformability and accordingly on the primary stability of the examined cups.

In vitro examination of the primary stability of three press-fit acetabular cups under consideration of two different bearing couples

BackroundFor preclinical statements about the anchoring behavior of prostheses, the primary stability of the prosthesis is of special importance. It was the aim of this study to examine and compare the relevant relative micromotions of three different acetabulum prostheses by introducing three-dimensional torques. MethodsThe cups were implanted under standard conditions into an anatomical artificial bone model. Three-dimensional torques were applied to the acetabular cups. Taking into account the resulting frictional moments of two different bearing couples, ceramic-on-ceramic and ceramic-on-polyethylene, the relative micromotions of the cups were recorded as maximum total micromotion, translational and rotational micromotion, and the primary stability values of the three cups were compared. ResultsRelative micromotion of all cup models was always significantly smaller with the CoC bearing couples than with the CoP bearing couples (p < 0.001). The rotational micromotion was always lower (p < 0.001) than the translational micromotion, and the rotational as well as the translational micromotions were each always lower than the maximum total micromotion (p < 0.001, p < 0.010). The thinnest-walled cup system always showed the largest relative micromotions. ConclusionThe results of our study can be interpreted as indicating that the low relative micromotions of all cups – irrespective of the use of CoC or CoP bearing couples – are within an acceptable range favoring secondary osseointegration of the implants. Furthermore, we were able to show that the cup wall thickness and the surface quality of the cup systems have an influence on the primary stability and the elastic deformability of the examined cup systems.

Numerical analysis on the elastic deformation of the tools in sheet metal forming processes

The forming tools are commonly assumed as rigid in the finite element simulation of sheet metal forming processes. This assumption allows to simplify the numerical model and, subsequently, reduce the required computational cost. Nevertheless, the elastic deformation of the tools can influence considerably the material flow, specifically the distribution of the blank-holder pressure over the flange area. This study presents the finite element analysis of the reverse deep drawing of a cylindrical cup, where the forming tools are modelled either as rigid or as deformable bodies. Additionally, the numerical results are compared with the experimental ones, in order to assess the accuracy of the proposed finite element model. Considering the elastic deformation of the tools, the numerical results are in better agreement with the experimental measurements, namely the cup wall thickness distribution. On the other hand, the computational time of the simulation increases significantly in comparison with the classical approach (rigid tools).

Drawing of Hexagonal Cup

The main aim of this work is to produce hexagonal cup drawn from flat sheet (blank Ø80) and effect of wall corner radii of die on drawing process. The dimension of diagonal and side hexagonal cup are (41,36mm) and (36 mm) respectively, and (0.7mm) thickness made from low carbon steel (1006–AISI), has been produced. A commercially available finite element program code (ANSYS11.0), was used to perform the numerical simulation of drawing operation. Two types of wall corner radii of die ( =0.7, 4 mm) with constant punch profile radius equal to ( =4) mm and die profile radius equal to ( =8 mm (were used to investigate the effect of die corner radius on punch force, variation of cup wall thickness and the strain distribution over the cup wall. The numerical results of this model were compared with experimental results and the results show that, the greatest thinning occurs when used wall corner radius of die equal to ( = 0.7mm) due to great stretching of the metal over the corner radius. The best strain and thickness distribution over all zones in produced cup obtained when using wall corner radius of die is equal to = 4 mm).

Numerical Analysis of The Multi-Stage Reverse Deep Drawing Process

The paper presents an analysis of the multistage deep drawing process considering the three deformation stages namely drawing reverse and reverse redrawingrespectively. This work aim to study the mechanism of deformation during the redrawing process where the second and the third stages were done in reverse redrawing and study the effect of this mechanism on produced cup wall thickness, strain distribution across the wall of the drawn part. 2-D model of cylindrical cup (46.75mm) diameter has been developed in the first stage from sheet with thickness (0.5mm) of the low carbon steel (AISI 1008) and (85mm) diameter, while for second and third stages of drawing a punch diameter (32.725mm, 27.489mm) respectively, and inside diameter of dies equal to (33.825mm, 28.589mm) respectively, the clearance is chosen for three stage equal to 0.55mm. A commercial available finite element program code (ANSYS 11), is used to perform the numerical simulation of the multistage deep drawing. The results show that, when considering multi-stage drawing, the task is even more difficult because the strain and thickness distribution resulting from the first stage will influence the subsequent results,increase in thinning in the wall cup will appear in the second and third stages. Finally this work introduces new method (multi reverse redrawing) to produce circular cup throw three stages of drawing reduction in one stroke without the need to the loading and unloading the tools among the stages as in direct redrawing which means reducing the cost, time, efforts and enhancing cup production.

Influence of the plastic anisotropy modelling in the reverse deep drawing process simulation

This study deals with the description of the anisotropic behaviour of the mild steel sheet used in the reverse deep drawing process of a cylindrical cup, which was proposed as benchmark at the Numisheet’99 conference. The effect of the yield criterion on the numerical results is analysed using three yield functions, von Mises, Hill’48 and Barlat Yld’91, combined with the Swift hardening law. The anisotropy parameters of the Hill’48 model are identified using either the yield stresses or r-values, obtained from the uniaxial tensile test at three different directions. On the other hand, the anisotropy parameters of the Yld’91 are determined taking into account both the yield stresses and r-values, minimizing an objective function. The comparison between experimental and numerical results is presented, being the punch force evolution and the thickness distribution along the cup wall the principal variables under study. In both forming stages, the predicted punch force evolution is close to the experimental one, whatever the yield criterion adopted. Nevertheless, the cup wall thickness distribution is strongly influenced by the yield criteria, being clearly overestimated by the von Mises yield criterion. On the other hand, the Yld’91 yield criterion provides a thickness distribution closer to the experimental one, for both forming stages. The strain paths during both forming stages ranges from uniaxial compression, when the material flows between the die and blank-holder, to plane strain in the cup wall, whereas the important strain path changes occurs in the die radius.

The influence of head diameter and wall thickness on deformations of metallic acetabular press-fit cups and UHMWPE liners: a finite element analysis

BackgroundTo increase the range of motion of total hip endoprostheses, prosthetic heads need to be enlarged, which implies that the cup and/or liner thickness must decrease. This may have negative effects on the wear rate, because the acetabular cups and liners could deform during press-fit implantation and hip joint loading. We compared the metal cup and polyethylene liner deformations that occurred when different wall thicknesses were used in order to evaluate the resulting changes in the clearance of the articulating region. MethodsA parametric finite element model utilized three cup and liner wall thicknesses to analyze cup and liner deformations after press-fit implantation into the pelvic bone. The resultant hip joint force during heel strike was applied while the femur was fixed, accounting for physiological muscle forces. The deformation behavior of the liner under joint loading was therefore assessed as a function of the head diameter and the resulting clearance. ResultsPress-fit implantation showed diametral cup deformations of 0.096, 0.034, and 0.014mm for cup wall thicknesses of 3, 5, and 7mm, respectively. The largest deformations (average 0.084±0.003mm) of liners with thicknesses of 4, 6, and 8mm occurred with the smallest cup wall thickness (3mm). The smallest liner deformation (0.011mm) was obtained with largest cup and liner wall thicknesses. Under joint loading, liner deformations in thin-walled acetabular cups (3mm) reduced the initial clearance by about 50%. ConclusionAcetabular press-fit cups with wall thicknesses of ≤5mm should only be used in combination with polyethylene liners >6mm thick in order to minimize the reduction in clearance.

Effect of Die Radius on Blank Holder Force and Drawing Ratio: A Model and Experimental Investigation

A numerical model for a newly designed deep drawing process has been built up and analyzed using the finite element method (FEM) in comparison with performed experiments using the DIN 10130-99-DC05 sheet material. It was aimed to increase the limiting drawing ratio (β) and decrease the blank holder forces (BHFs). To predict the deformation behavior of the process, the parameters are analyzed using FEM. The effects of the die radius, blank holder and punch forces, friction, cup wall, and blank thickness in the process were investigated. A deep drawing die set was designed and manufactured, and the validity of the design was demonstrated through the theoretical and experimental analysis. The results showed that the blank holder die radii and friction have the greatest effect on the thickness of deformed steel cups. The drawing ratio of β has an influence on the BHFs and it decreased with increasing die angle (α). The β was considerably increased by 26% compared with dies having no angle (α = 0°). The current design and analyses can help the optimization of the control scheme of drawing processes rather than using the conventional designs. A comparison of the predicted and experimental results showed good agreement.

An experimental investigation of forming load and side-wall thickness obtained by a new deep drawing die

Deep drawing is an important process used for producing cups from sheet metal in large quantities. The deep drawing process is affected by many variables such as blank shape, punch and die radii, material’s formability characteristics, and many more. In order to obtain optimal process parameters with regard to part geometry, the blank and die geometry are particularly important factors. In this study, we investigated the effects of blank holder and die shapes, using six different blank holder and die shapes. We measured the distribution of blank holder force (BHF), the forming load at different drawing depths as well as thickness reduction of cup wall thickness for each set of die and punch geometries. The experimental study shows that the angle of blank and die surface influence the forming load and blank holder force distribution. Deep drawing dies with matrix and blank holder angle designed in this study provided deep drawing ratios that are about 25 % larger than those that usually can be obtained by a conventional die.

Effect of the blank holder force on drawing of aluminum alloy square cup: Theoretical and experimental investigation

In this study, the influence of AA5754-O material, an aluminum alloy, in forming the blank holder force (BHF) in deep drawing process has been investigated. For this purpose, a new experimental system has been prepared. By means of this system, deep drawing process can be implemented through applying variable forces in computer-controlled manner on the blank holder and sheet plate. The numerical model of forming with deep drawing process has been built up and analyzed via the LS-DYNA software. Cup depths, tearing and wall thickness variations of the experimental and numerical results have been compared. It has been observed that no earing and wrinkling have occurred in BHF's between 1.3 and 8 MPa in square deep drawing process, and that tears have occurred in forces exceeding 18 MPa. It has further been observed that the best forming has occurred at 5 MPa, and that the numerical and experimental model developed is in harmony with one another at a rate of 85%.

Effect of Punch Geometry in the Deep Drawing Process of Aluminium

The effect of different punches head profile on deep drawing of 5005 H34 Aluminium circular blanks to manufacture a cup-shape product were studied. Experiments were conducted by a 150 ton hydraulic press with using different punches geometry and lubricants viscosity. The drawing force, blank holder pressure, and movement of the punch were measured during experiments to monitor effects of various manufacturing parameters during the drawing process. The surface finish and dimensions of all cups were determined after drawing processes. The geometry of the punch influences the friction force between the blank and punch, and consequently the stretching bottom surface of the cup. The Flat punch geometry produced cups with better surface finish, higher drawing force, and thinner cup wall thickness in comparison to other punches geometry. The Bore punch geometry enhances the stretching of the bottom part of the cup. The presence of lubricant in the process improves the stretching of bottom part of a cup for all punches profile.

Evaluation of milli-scale cylindrical cup in two-stage deep drawing process

In this study, to enhance the accuracy of products in metal forming, the product accuracy in two-stage cylindrical cup deep drawings was investigated. To consider the local and global forming factors simultaneously, we focused on milli-scale order, which is classified as the intermediate region between micro- and macro-scales. For evaluation of the drawn cups, the cup wall geometry, thickness distribution and surface roughness were precisely investigated using both experimental and finite element (FE) analyses. Milli-scale deep drawing experiments were performed with mirror-polished and unpolished tool sets to investigate the effect of tool roughness. The validity of the modeling of surface roughness as well as the effect of tool roughness on drawn cup surface accuracy was investigated via FE simulation. Some evaluated characteristics in the experiment were in good agreement with FE simulation results. It was also shown that tool roughness is strongly related to frictional behavior, but does not affect the cup surface accuracy under the condition of less than 0.1 μm tool roughness.

Importance of Head Diameter, Clearance, and Cup Wall Thickness in Elastohydrodynamic Lubrication Analysis of Metal-On-Metal Hip Resurfacing Prostheses

The main design features of metal-on-metal (MOM) hip resurfacing prostheses in promoting elastohydrodynamic lubrication were investigated in the present study, including the femoral head diameter, the clearance, and the cup wall thickness. Simplified conceptual models were developed, based on equivalent uniform wall thicknesses for both the cup and the head as well as the support materials representing bone and cement, and subsequently used for elastohydrodynamic lubrication analysis. Both typical first- and second-generation MOM hip resurfacing prostheses with different clearances and cup wall thicknesses were considered with a fixed large bearing diameter of 50 mm, as well as a 28 mm diameter MOM total hip replacement bearing for the purpose of comparison. The importance of the head diameter and the clearance in promoting elastohydrodynamic lubrication was confirmed. Furthermore, it was also predicted that a relatively thin acetabular cup in the more recently introduced second-generation MOM hip resurfacing prostheses would be capable of improving elastohydrodynamic lubrication even further.

Investigation into the effect of a sandwich acetabular cup upon lubricant film thickness in metal-on-metal total hip replacements

The development of a large lubricant film thickness generally depends upon the large elastic deformations of the bearing surfaces from the elastohydrodynamic lubrication (EHL) point of view. The deformation of the bearing surfaces of total hip joint replacements can be influenced by the material properties as well as the structural supports. A conceptual sandwich cup, which consists of a hemispherical metallic bearing shell bonded to a polyethylene backing, together with a solid metallic femoral head was considered in an EHL analysis for quasi-static conditions of load and speed to investigate the effect of the sandwich cup upon lubricant film thickness in total hip replacements. It was found that a reduction in the cup wall thickness of the metallic shell and an increase in the polyethylene thickness resulted in an increase in the predicted lubricant film thickness and a decrease in the hydrodynamic pressure. A general relationship was found between the film thickness and the metallic inlay thickness.

Deformation of press-fitted metallic resurfacing cups. Part 2: Finite element simulation

The deformation of metallic acetabular cups employed for metal-on-metal hip resurfacing procedures was considered theoretically using the finite element method in the present study, following on the experimental investigation reported in Part 1. Three representative cups, characterized by the cup wall thickness as thin, intermediate, and thick, were considered. For the intermediate cup, the effects of both the size and the diametral interference on the cup deformation were investigated. Both two-dimensional axisymmetric and three-dimensional finite element models were developed to examine the important parameters during and after the press-fit procedure, and in particular the deformation of the metallic cup. The theoretical prediction of the cup deformation was in reasonable agreement with the corresponding experimental measurement reported in Part 1. The most significant factor influencing the cup deformation was the cup wall thickness. Both the size and the diametral interference were also shown to influence the cup deformation. It is important to ensure that the cup deformation does not significantly affect the clearance designed and optimized for tribological performances of metal-on-metal hip resurfacing prostheses. Furthermore the contact parameters at the cup and bone interface associated with the press fit were also discussed.

Deformation of press-fitted metallic resurfacing cups. Part 1: Experimental simulation

The interference press fit of a metallic one-piece acetabular cup employed for metal-on-metal hip resurfacing procedures was investigated experimentally under laboratory conditions in the present study, in particular regarding the cup deformation. Tests were carried out in cadavers as well as polyurethane foams of various grades with different elastic moduli to represent different cancellous bone qualities. The cadaver test was used to establish the most suitable configuration of the foam model representing realistic support and geometrical conditions at the pelvis. It was found that a spherical cavity, with two identical areas relieved on opposite sides, was capable of creating a two-point pinching action of the ischeal and ilial columns on the cup as the worst-case scenario. Furthermore, the cup deformation produced from such a two-point loading model with a grade 30 foam was similar to that measured from the cadaver test. Therefore, such a protocol was employed in subsequent experimental tests. For a given size of the outside diameter of the cup of 60 mm, the cup deflection was shown to be dependent largely on the cup wall thickness and the diametral interference between cup and prepared cavity at implantation. For a relatively thin cup with a wall thickness between 2.3 mm (equator) and 4 mm (pole) and with a modest nominal diametral interference of 1 mm, which corresponds to an actual interference of approximately 0.5 mm, the maximum diametral cup deflection (at the rim) was around 60 microm, compared with a diametral clearance of 80-120 microm between the femoral head and the acetabular cup, generally required for fluid-film lubrication and tribological performances. Stiffening of the cup, by both thickening and lateralizing by 1 mm, reduced the cup deformation to between 30 and 50 microm with actual diametral interferences between 0.5 and 1 mm.