Die Geometry Research Articles

Residual Stress Engineering for Wire Drawing of Austenitic Stainless Steel X5CrNi18-10 by Variation in Die Geometries-Effect of Drawing Speed and Process Temperature.

As a result of conventional wire-forming processes, the residual stress distribution in wires is frequently unfavorable for subsequent forming processes such as bending operations. High tensile residual stresses typically occur in the near-surface region of the wires and can limit further application and processability of the semi-finished products. This paper presents an approach for tailoring the residual stress distribution by modifying the forming process, especially with regard to the die geometry and the influence of the drawing velocity as well as the wire temperature. The aim is to mitigate the near-surface tensile residual stresses induced by the drawing process. Preliminary studies have shown that modifications in the forming zone of the dies have a significant impact on the plastic strain and deformation direction, and the approach can be applied to effectively reduce the process-induced near-surface residual stress distributions without affecting the diameter of the product geometry. In this first approach, the process variant using three different drawing die geometries was established for the metastable austenitic stainless steel X5CrNi18-10 (1.4301) using slow (20 mm/s) and fast (2000 mm/s) drawing velocities. The residual stress depth distributions were determined by means of incremental hole drilling. Complementary X-ray stress analysis was carried out to analyze the phase-specific residual stresses since strain-induced martensitic transformations occurred close to the surface as a consequence of the shear deformation and the frictional loading. This paper describes the setup of the drawing tools as well as the results of the experimental tests.

Analysis of the influence of dies geometry on the process extrusion force and properties of the extrudate obtained in the process of cold extrusion of 7075 aluminum alloy by the KOBO method

Abstract The KOBO extrusion process is an unconventional method of extrusion based on the phenomenon of superplasticity as an effect of a special state caused by the oscillatory motion of the die at a certain angle a certain frequency. It significantly lowers the extrusion force and makes it possible to extrude lightweight metals and alloys (e.g. aluminum and magnesium alloys) in cold extrusion with high extrusion ratios compared to conventional hot extrusion. This work studies the influence of the tool (die) geometry on process realization parameters and the properties of the extrudate. Experimental studies of cold KOBO extrusion were performed using dies with different face portion geometry. The obtained extrudate obtained from EN-AW 7075 aluminum billets was examined for mechanical properties and macro/microstructure, showing that, with adequate modifications to the tool face part geometry, it is possible to lower the extrusion force and obtain extrudate with desired properties.

Numerical and experimental investigations on AA6063 extrudates: effect of number of portholes on extrusion load and weld strength

In aluminium extrusion process, metal flow is greatly controlled by the die geometry and a variety of intricate profiles can be achieved by designing dies of different configurations. In porthole die extrusion, number of portholes used for a profile is often determined by the subjective knowledge of designers. Nevertheless, extrusion load and weld strength of profile produced are not only dependent on extrusion ratio, temperature of deformation but also on the number of portholes along with other die geometry variables. In the present investigation, systematic studies were carried out on three different dies with four ports, three and two ports around die center to extrude profiles of outer diameter 29.4 mm and thickness 2 mm. Numerical simulations were carried out for estimation of pressure, temperature, strain, and strain rate parameters in the weld chamber for all the dies, followed by press trials and profiles produced were subjected to wedge expansion test. The results from numerical simulations indicated that pressure generated inside weld chamber increases with number of portholes. The surface plots indicated highest pressure of about 280 MPa for four port hole and about 276 MPa for three ports die and pressure of about 160 MPa was estimated for two port hole die at the entry of weld chamber , which is 65 mm from profile end. Similarly, temperature at profile exit was 551 °C for four portholes die and 546 °C for three portholes die and 537 °C for two portholes die. Furthermore, press trials indicated peak extrusion loads of 5241 kN, 4406 kN and 3961 kN respectively for four, three and two portholes die. Thus, the peak extrusion load decreased by about 16% for three port and about 25% for two ports die in comparison with four port die. Also, the extruded profiles in wedge expansion test indicated mean compression load of 22.70 ± 0.14 kN in four porthole die, mean compression load 22.29 ± 0.26 kN for three port die and mean compression load of 17.841 ± 0.27 kN.

Effect of Strain Per Pass on Microstructure and Mechanical Properties of Multi-Axially Forged Cast AA5083 Alloy at Room Temperature

This paper investigates the effect of strain per pass over a cycle on, multi-axially forged cast AA5083 alloy at room temperature. To begin with, Multi-Axial Forging (MAF) with two different strains per pass was imposed on the alloy without changing the die geometry. Samples were deformed to cumulative strains of Σɛ = 2.46 (2 Cycles) and Σɛ = 2.79 (3 Cycles), with two different strains per pass ε = 0.41 and ε = 0.31 respectively. Microstructural analysis was carried out by using OM, XRD, and SEM with EDS. Structural changes were characterized, and it was revealed that grain fragmentation was caused by the frequent development of deformation and micro shear bands, which was followed by the evolution of new fine grains in the original grain structure. Mechanical properties were evaluated by tensile, and hardness tests. MAF of ɛ = 0.41 per pass results in high tensile strength and hardness, 428 MPa and 147 Hv; respectively at a cumulative strain of Σɛ =2.46. Processing with strain ɛ = 0.31 per pass produced strength of 380 MPa and hardness of 131 HV after cycle III with a cumulative strain of 2.79. MAF of strain ɛ = 0.41 per pass with cumulative strain of 2.46 resulted in a higher grain refinement structure with increased strength compared to a strain of 0.31 per pass with a cumulative strain of 2.79. Therefore, with the imposition of the high strain per pass produced more grain refinement and consequently higher strength.

Influence of deformation path on the stress state and damage evolution along the central axis of a large size forged ingot of AISI H13 steel

Development of cracks along the center axis of large high strength steel bars commonly occurs during the forging and leads to excessive part rejections. The present investigation aims to develop a better understanding of the evolution of stress-strain states during the forging operation and in particular the effect of deformation path illustrated by die geometry, on the evolution of damage during the cogging of an AISI H13 steel. Hot compression and tensile tests were performed using Gleeble-3800 thermo-mechanical simulator to develop the optimum material model which was then implemented in the finite element (FE) code Forge NxT 3.2® using a developed user subroutine. Normalized Cockcroft and Latham damage criterion and maximum shear stress (Tresca's) theory of failure were used to predict the damage and failure in the center axis of the shaft through FE analysis with three different die shapes: concave, flat, and convex. A comparative study between the three die geometries was conducted to quantify the effects of each of them on the sensitivity to central burst damage. FE model was validated using industrial data. The lowest and highest damage values were found to occur in the case of cogging with concave and flat die, respectively. The coefficient of variation (CoV) is employed as a measure of heterogeneity and it was found that the concave die provides more uniform deformation and most favorable results for the cogging compared to the flat and convex dies. The novel approach, application of concave die successfully implemented at the industrial scale cogging.

Microstructure, segregation and mechanical properties of A356 alloy components fabricated by rheo-HPDC combined with the swirled enthalpy equilibration device (SEED) process

The challenges commonly associated with conventional high pressure die casting (HPDC) have led to increased interest in semi-solid metal (SSM) forming processes. In the present study, semi-solid slurries of A356 alloy prepared by the Swirled Enthalpy Equilibration Device (SEED) process were used for manufacturing components with complex shape by using a high pressure die casting machine. The segregation phenomenon and the effect of heat treatment on the microstructure evolution and mechanical properties were investigated. The results showed that the alloy consists of primary spherical α-Al grains, secondary solidified α-Al grains, eutectic Si, iron-rich intermetallic phases and low porosities. The microstructural investigations revealed that the eutectic Si particles underwent fragmentation, spheroidization and coarsening with increasing solution temperature. Furthermore, the solution treatment results in the dissolution of the π-Al8FeMg3Si6 phase and the growth of the β-Al5FeSi phase. The hardening peaks at 170 °C could be obtained with ageing for 5 h. Due to both solution and precipitation strengthenings, the yield strength, ultimate tensile strength and hardness of A356 alloy after heat treatment increase significantly compared to those in the as-rheocast state: they reach 266 MPa, 343 MPa and 110 HV0.2, respectively. The analysis of fracture surfaces of rheo-HPDC samples in both the as-rheocast and the heat-treated states revealed a mixed mechanism of dimples and quasi-cleavage. The microstructure inside the part was found to be quasi-homogeneous while the segregation phenomenon in different zones of the part is affected by die geometry during the filling process. The results imply that the SEED-HPDC process has the potential to be industrialized by implementing appropriate heat treatments for producing complex components with good mechanical properties.

Theoretical and Experimental Study on Wear Behavior in Order to the Improvement of Die Geometry in the Radial Forging Machine

Deformation of shafts and seamless tubes are carried out by a radial forging machine in order to achieve the required dimensions and improve the mechanical parameters of the material. Hence, the study of improving the performance of the radial machine leads to an increase in the quality of the forged tube, while the machine equipment in the process of radial forging will have the least erosion. In this process, the workpiece is surrounded by four tools and during the repeated blows of the die, the desired dimensions of the workpiece are obtained. with regards to the contact surface of the die with the workpiece, the most common tool that faces the highest erosion is the die. Therefore, the improvement of die geometry in order to minimize wear has been investigated in this article. Also, the distribution of die temperature and analysis of die stress during the process has been implemented. Accordingly, three types of die geometries: Flat, Concave and Convex are considered to measure the depth of wear and determine the maximum erosion through 3D finite element simulation and experimental estimates. Therefore, according to the comparison between numerical and analytical results in the case of wear analysis with experimental results, the validation of simulation was confirmed.

Impact design of die parameters on Severe plastic deformation during Equal channel angular pressing: An overview

Equal channel angular pressing causes less uniform deformation than simple shear, even though its not as obvious as with other metal forming procedures. Investigation is done into how internal and external factors affect the deformity inhomogeneity through Equal .channel angular pressing. Finite element analysis of plastic deformity are integrated with die corner angle and the strain harden ability of metallic workpiece. The material characteristics are significantly influenced by the type of plastic shear deformation that occurs through Equal channel angular pressing and this is primarily impacted by the die geometry, the properties of the material and the process factors. Segmenting the workpiece into a front transient zone, end transient zone, outer less sheared zone and the remaining shear deforming zone allowed researchers to examine the uneven strain distribution throughout the workpiece. The deformed geometry for the non-hardening and it was assumed that rate-insensitive materials would be largely homogeneous. In materials that are strain-rate sensitive, gaps between the upper and lower channels developed, whereas strain-hardening materials experienced the corner gap. The strain hardening and implications of strain-rate sensitivity exponent had a considerable impact on the deformation inhomogeneity. Metals having an ultrafine grain microstructure can be created by severe plastic deformation. The FE models were used to affect the process and they all took as inputs the material properties, load variation, Different velocity and boundary conditioned. For the purpose of evaluating the impact of the channel angle on the AA5083 sample, The FE analysis produced the value of strain distribution. When the channel angle was 1200, there was less strain overall, but there was also less concentrated stress in the channel corner area.

Simulation of deformation behaviour of Aluminium 7075 during Equal Channel Angular Pressing (ECAP)

This paper presents a finite element simulation of equal channel angular pressing (ECAP) since it is one of the most common and successful severe plastic deformation techniques. This study reports the influence of the most significant factors influencing the ECAP technique. Through finite element simulation, the effect of the die geometry, workpiece geometry, and the pressing speed on the effective strain distributions, damage, and pressing loads, were investigated. The influence of the ECAP method on different material models is also presented. Additionally, the prospective expansion and future applications of ECAP are herein highlighted. From the results, the die geometry of a 90° channel imparts the highest strains during ECAP. Additionally, specimens of rectangular geometry are susceptible to cracking and damage as compared to circular samples. It was found that very high processing speeds (>7mm/sec) are undesirable during ECAP since they cause very high internal stresses to the structure of the workpieces. Besides, processing at room temperature can achieve homogeneous strain distribution with minimum sample damage.

The Effect of Die Geometry on Cup Damages in Cold Deep Drawing of Rectangular Cups

Derin çekme, zımba kuvveti uygulanarak sac malzemenin kalıp boşluğuna akışıdır. Derin çekmede, düz ince tabakalar arasında sacı istenen şekle getirmek için zımba kullanılarak sacı merkez kısmından kalıp boşluğuna iterek kaplar üretilmektedir. Derin çekilmiş kaplarda kabın köşe yarıçaplarında boyun oluşumu veya çatlamaların oluşması nedeniyle daha yüksek çekme oranları elde edilememektedir. Bunun için derin çekme işleminin başarılı olmasında uygun işlem parametrelerinin doğru seçilmesi önemlidir. Bu makalede, dikdörtgen geometriye sahip kapların derin çekilmesinde matris üst yüzeyine ve pot çemberinin alt yüzeyine açılar verilerek matris geometrisinin, kap kesit incelmeleri ve hasarları üzerinde olan etkileri tespit edilmiştir. Bunun için matris üst yüzeyine/pot çemberi alt yüzeyine 0°, 3°, 6° ve 9°’lik açılar verilmiştir. Pot çemberi kuvveti sabit 1800 daN ve stampa hızı da sabit 4 mm/s olarak uygulanmıştır. Derin çekme işlemlerinde, matris/stampa arası boşluk 1.2 mm, stampa uç ve kenar radyüsleri ile matris ağız yarıçapları 6 mm alınmıştır. Çalışmada kalınlığı 1 mm olan St37 çeliği kullanılmıştır. Cidar kalınlıkları Mitutoyo LH-600E hassas lineer ölçüm cihazında 0.001 hassasiyetinde nokta temaslı olarak ölçülmüştür. Kap yükseklikleri artıkça kaplardaki cidar incelmelerinin arttığı, maksimum incelmenin kabın alt kısımlarındaki köşelerde meydana geldiği ve bu değerin 0,373 mm olduğu tespit edilmiştir. Plastik deformasyonun en çok etkilediği bölge kap alt bölgesidir. Bu bölgede deformasyon sertleşmesi nedeniyle maksimum basma ve çekme kuvvetleri oluşmakta ve dolayısıyla maksimum gerilme ve sertlik bu kısımda meydana gelmiştir. Maksimum sertlik kabın tabanının olduğu bölgede ve 61.4 HRC olarak ölçülmüştür. Minimum sertlik kap üst bölgesinde ölçülmüştür. Kabın üst ağız kısımlarına doğru sertliğin daha da düştüğü ve 43.8 HRC olduğu görülmüştür. Ortalama sertlik değeri ise 53.1 HRC olarak tespit edilmiştir. Sonuç olarak, dikdörtgen geometriye sahip kapların soğuk derin çekilmesinde, matris üst yüzeyine ve pot çemberinin alt yüzeyine açılar verilerek kalıp geometrisinin, kap cidar kalınlık değişimleri ve kap hasarları üzerinde önemli bir etkisinin olduğu tespit edilmiştir.

Ön Deformasyona Uğratılmış Hammadde Kullanılarak Paslanmaz Çelik Bağlantı Elemanının Simülasyon Destekli Soğuk Dövme Üretimi

The initial properties of the raw material used while producing by cold forging change the mechanical properties of the final product resulting from deformation. Depending on the amount and speed of deformation, there is an increase in strength and a decrease in formability after cold forging on the basis of the true stress - strain curve of the material. In this study, pre-deformation of 304Cu (1.4567) quality raw material used to produce fasteners in A2-70 class by wire drawing before forging and the change of the mechanical properties of the raw material, on the basis of this change, the simulation supported design of the fastener mold and process was carried out. Simufact.forming software was used in cold forging simulation studies. According to the simulation data, the yield strength value increased from 215 MPa to 620 MPa as a result of thinning the raw material from Ø7.80 mm to Ø6.95 mm with wire drawing operation. In this case, the properties of the raw materials entering the cold forging have changed according to the deformation percentage amount, and the material properties and mold design used in the finite element simulation supported production were made according to this data. As a result of the use of this raw material in the cold forging simulation, the HV10 hardness value in the fastener head region, where deformation is intense on the basis of the die geometry, has reached the levels of 320 to 340 HV. Material flow lines, product dimensional tolerances, rolling and thread cutting processes during deformation were verified in the computer environment and physical product production was made. Hardness, strength and structural checks were performed and compared with numerical model values. Especially, the changing material properties as a result of the wire drawing process applied to the starting raw material and its effect on cold forging were investigated mechanically and metallographically.

Analysis of Side-Wall Wrinkling in Deep Drawing Processes

Wrinkling, developed due to compressive instability, is one of the main failure modes in deep drawing processes. Depending on the die geometry and blank holder force, it can be observed as flange wrinkling and/or side-wall wrinkling. In this study, side-wall wrinkling in cylindrical cup drawing process is investigated by using different constitutive models that are formed by using CPB06ex2, Hill’48, BBC2008-8p and BBC2008-16p yield criteria with isotropic hardening, and von Mises yield criterion with isotropic, kinematic and combined hardening. Numerical simulations are performed by implementing CPB06ex2, BBC2008-8p and BBC2008-16p models to a commercial finite element code through user subroutines. AA5042-H2 aluminium alloy is selected as a sheet material with 0.2083 mm thickness. In order to verify the developed models, the experimental results of the previous works for wrinkling profile and punch force evolution are employed. The results are compared and presented for the considered yield criteria.

On the reliability of yield functions in deep drawing simulations

In sheet metal forming simulations, the yield functions are usually calibrated based on experimental data, and validated by comparing the modelled and measured r-values and (in more advanced models) yield stresses along various in-plane directions. The fitted yield function should ideally reproduce (or interpolate) all the experimental values used for the fitting. However, this requirement does not guarantee accurate results in a forming process simulation, and it can even lead to unexpected results. The performance of a yield function, in addition to the fitting procedure, depends on the active loading modes which the material experiences during the simulation. The active loading modes are in turn determined by the die geometry as well as the process parameters like blank holder force and lubrication. As a consequence, the performance of a yield function, which is fitted to simple experimental data, is not identical for different forming conditions. Therefore, the application of each model is usually limited to a range of materials and processes, and this applicability is often evaluated based on experience. In the present study, we examine three phenomenological yield functions and a new crystal plasticity based material model for cup drawing process simulation with an AA6016-T4 aluminium alloy. These functions are different in their input data types used for the calibration. The results surprisingly shows that the models with more experimental data (in particular, yield stresses in different directions) in their formulation not only predict unexpectedly wrong results, but also show strong sensitivity to some of those additional input data and even to modelling parameters like the friction coefficient.

Numerical analysis of AISI 321 alloy material parameters on rubber pad diaphragm forming

Rubber pad diaphragm forming is a technology that uses a rigid die in conjunction with a flexible polyurethane tool and fluid pressure action in order to shape metal sheets. In this process, the action of the fluid forms a polyurethane tool, which forces the sheet to acquire the geometry of the die, being this process quite different from the classical stamping processes. The rubber tool is compatible with different die geometries, which allows a quick reconfiguration of the system, making it adequate for the production of small batches in the aeronautical sector. In this study, an advanced numerical model of the process is developed, in order to obtain a simulation that allows comprehensive understanding of the technology. An advanced characterization of the AISI 321 stainless steel is carried out, evaluating different yielding criteria. On the other side, the hyperelastic behaviour of the polyurethane rubber is taken into account. The main goal of the study has been to perform a sensitivity analysis of the sheet material parameters and to understand their influence on the final numerical results.

A Review on Effect of Stress and Strain Distribution on the AA5083 With Respect to Different Channel Angle of ECAP

The focus of this study was on the effect of channel angle on stress distribution in the material aluminum alloy 5083. The mechanical properties of a mate- rial are related to the grain size. Equal channel angular pressing (ECAP) is a method for deforming materials in such a way that a strong mechanical prop- erties material is formed while the dimensions of the work piece stay fixed in order to make ultra-fine-grained materials. One of the parameters of ECAP is the channel angle. It’s crucial to understand the impact of a die channel angle on material stress distribution before designing one. When the work piece passes through the channel angle, the die channel angle is built differently to see the effect of stress distribution. At the place where the die’s channels angle intersected, the grain structure was evaluated. The result of the influence of die channel angle on stress distribution is shown in this study’s analysis. It is well established that the channel angle has an impact on mechanical behaviour. The inhomogeneity index (Ci)and standard deviation (S.D.) are two approaches for assessing strain homogeneity. Ciis demonstrated to be an ineffective tool for analysing strain distribution homogeneity. Furthermore, it is advised that constructing Equal Channel Angular Pressing die geometry to obtain the best strain circulation homogeneity rather also the best efficient strain consequence is preferable.

Optimization of a Flat Die Including Elongational Viscosity Effects

Abstract A software package for optimization of polymer extrusion dies is developed. Die geometry is optimized such that a uniform velocity distribution is obtained at the die exit without excessively increasing the pressure drop in the die. The software uses the BFGS optimization algorithm, and employs the adjoint method to obtain the design sensitivities. The optimization software is successfully used to optimize the geometry of a flat die for polymer sheet extrusion such that a uniform velocity distribution is obtained at the die exit, without increasing the pressure drop in the die.

Analysis of Tool Geometry for the Stamping Process of Large-Size Car Body Components Using a 3D Optical Measurement System.

The paper presents a method for checking the geometry of stamped car body parts using a 3D optical measurement system. The analysis focuses on the first forming operation due to the deformation and material flow associated with stall thresholds. An essential element of the analysis is determining the actual gap occurring between the forming surfaces based on the die and punch geometry used in the first stamping operation. The geometry of car body elements at individual production stages was analyzed using an optical laser scanner. The control carried out in this way allowed one to correctly position the tools (punch and die), thus introducing the correction of technological parameters, having a fundamental influence on the specific features of the final product. This type of approach has not been used before to calibrate the technological line and setting of shaping tools. The influence of the manufactured product geometry in intermediate operations on the final geometry features was not investigated.

Influence of Die Threading and Finishing Length in the Thread-Rolling Process Using Flat Dies: A Numerical Analysis

In this paper, a numerical analysis of the cold thread-rolling process using flat dies is presented as a function of the die geometry design. Five die geometries with different threading and finishing ratios were modelled to induce different screw deformation rates. An analytical method was proposed by the authors to design die geometries as a function of screw roll rotation. Screw geometry accuracy, induced stress, and die wear were selected to compare the tested geometries. The results showed that three screw rotations in the threading step were sufficient to guarantee good geometry accuracy. Moreover, the results highlighted that die wear is the most affected parameter among all the tested geometries. Finally, a new solution was proposed by the authors to obtain uniform wear and reduce the die length.

Optimization of Die Design to Abolish Surface Defect on Telescopic Front Fork (TFF) Tube

Background: The telescopic fork is mainly used for suspension purposes in different devices to absorb the vibration and disturbances which come from the road or mechanical devices. Factors such as die angle, drawing velocity, lubrication, and area reduction per pass significantly affect the drawing loads and residual stresses formed in the drawn tube during the tube drawing process. Objective: An instantaneous transverse crack was found on the pipe's outer surface during the drawing process in the current work, and the key challenges were to reduce the percentage of pipe rejection. Methods: In this work, optimum drawing die designs were proposed by using the Finite Element Method (FEM). The FEM solving tool is called Abaqus, and it has been used for simulating and solving the cold-rolling process. The FEM model of cold drawing process is generated in Abaqus with the same boundary condition (Axial load and constrain) as used on the actual wire drawing machine. Result: With current die geometry, there was a substantial reduction in area, axial stress (Tensile) along the die side is 672 MPa, which is 23 % lower than the current die axial stress value 877 MPa. There was 48 % plastic strain found along the purposed die side, which was 17 % lower than the existing strain of 64%. Finally, the area was reduced by changing the die geometry from the current level of ~52% to 35 to 40 %. Conclusion: By reducing the area (35 to 40 %) in the output tube, and strain (17 %), it was possible to abolish the transverse crack on the pipe's outer surface. As part of the optimisation of the FEM work process, this work gives us encouraging results. Further research will be considered for future work.

Design Parameters for Equal-Channel Angular Pressing (ECAP) Via Numerical Approach

A numerical approach utilizes to investigate the optimal die design parameters of the ECAP technique. The Deformation behavior and strain distribution are affected by die geometry and processing parameters. were analyzed and evaluated. In addition, the influence of the inner channel angle (ICA) and the outer channel angle (OCA) on the behavior of plastic deformation during ECAP process also studied using a finite element technique. The numerical investigation implemented over a range of die angles (90°, 110°, and 135°) with inner corner radius (0, 3, 4, 5, and 8 mm) with their corresponding values considered for the outer corner radius (0, 10, 12,14,15 and 20 mm). The results obtained regarding the force required, maximum stress, maximum strain, and equivalent stress evaluated over a range for die inner angle radius and die outer angle radius. These results show that the size of the inner and outer curvature radii has a big effect on deformation homogeneity of the billet. had an influence on both the quantity and distribution of effective strain. With the increment of inner and outer curvature radii, the effective strain value decreased in the deformation regions. Moreover, the optimum conditions in terms of strain distribution and homogeneity of billet are associated with a radius of the inner fillet of 4 mm and radius of outer corner of 12 mm. The impacts on the von Mises strain and the press force. The optimal compromise between applied force and von Mises strain balances small press forces and high von Mises strain and homogeneity indices.