Punch Velocity Research Articles

Four Earing’s Prediction in Deep Drawing of AISI 1008 Steel Sheet Conical Product

Earing is a phenomenon that appears in deep drawing of parts produced using this process because of the anisotropic material properties. Most of, recent theories didn’t fully employ the mechanical materials properties, and ears number achieved depends on the FE simulation approaches. To anticipate the ears form issue in conical parts of AISI 1008 steel sheet deep drawing, in this work a new method is used to predict the earing formation during deep drawing. This method proposed combines the yielding limits and anisotropy r-values of the material to determine Hill48 yield criterion variables using several conical angles with several punch velocities. Equation for the value of yielding and anisotropy index for different orientation is used. AISI 1008 steel sheet is used as a case in this work, the zone of deformation or blank is partitioned radially to equal parts according to the anisotropic behavior. Hill48 yield function constants solved based on the material yielding point and anisotropy index together for the parallel deformed regions. A simulation using FE software for the process on the base of this method is executed to compare it results of lab work. and it noticed that Increasing speed may contribute slightly in decreasing the severity of anisotropy effect and this can be explained the process propagate the material need time to flow and if the speed increase this lead to increasing in strain hardening of the material[m]. Increasing die angle shows that the different between the highest point to lowest point in the cup edge may increase. This work produces a conductive and dependable way to anticipate the forms of earing during cup drawing, which will have positive effective in manufacturing implementations and numerical outcomes and shows high agreement with lab work.

Effect of temperature and load during hot impression creep of Cu-Zn-Al alloy

The creep behaviour of Cu-Zn-Al alloy was investigated using hot impression creep test. The test was performed on Cu-Zn-Al alloy cylindrical samples of 10 mm height and 15 mm diameter whose chemical composition was determined by X-ray Fluorescence (XRF) and Energy Dispersive Spectroscopy (EDS) Analysis. The creep tests were carried out for a dwell time of 3 h at three different loads 2 kg, 2.5 kg, 3 kg and at three different temperatures 250 °C, 300 °C and 350 °C for each load. The effect of load and test temperature on the creep behaviour was studied and it was observed that with increase in both temperature and load, the indentation depth as well as the creep rate increased. The punch velocity decreased with time in each case but increased with load and test temperature. Scanning Electron Microscopy (SEM) analysis around the indentation region after the creep revealed the presence of deformation bands and EDS Analysis indicated an increase in oxygen content of the alloy with test temperature.

Physiological Parameters of the Performance of Ballistic Punch Movements in Athletes

The motor-coordination features of punch actions in athletes receive special attention in the literature. However, the association between punch force actions and the mechanisms of motor coordination and balance is disregarded in the majority of studies, and a hierarchic movement organization adequate to the motor task consequently escapes attention. Vegetative support of various types of punches is poorly understood. Vertical stability, stabilographic parameters, muscle electrical activity of the upper limbs and trunk, and vegetative vascular support of various types of punch movements were studied using sports equipment in boxers of various skill levels. The results were used to systematize the physiological characteristics of punch movement performance in boxers. A higher level of qualification was associated with an increase in balance retention time in the complicated Romberg position. For the ballistic type of punch, the sagittal linear velocity of punch increased with the increasing qualification level and a pronounced frontal velocity component became detectable at the level of Candidate Master of S6ports (CMS). The changes were accompanied by an increase in the amplitude of bioelectric activity of muscles in the upper and lower limbs; signs of muscle disorganization were replaced by synchronization of bioelectric activity. Changes in motor pattern were accompanied by a nonlinear reorganization of the vegetative support system, and blood supply and blood return gradually increased in the lower and upper limbs. Blood circulation indices became more economic and optimal for ballistic technology. Based on the results, the development of sports mastery in boxing was considered as the development of a single functional system in which the ability to maintain balance and the punch velocity parameters are associated with an adaptive reorganization of contractile muscle activity in the lower and upper limbs and vascular maintenance of body activity. The findings help to better understand the physiological mechanisms underlying the formation of punch movement skills in combat sports and can provide a theoretical basis for improving the training process.

THE EFFECT OF PUNCH GEOMETRY ON PUNCHING PROCESS IN TITANIUM SHEET

Reducing punch force, increasing the sheared surface, and improving the work hardening have been real challenges in developing a punching process, and the right selection of punch geometry can resolve these challenges. Selecting the appropriate geometry, however, has been difficult to do since the effect of punch geometry on the punching process is rarely studied, and therefore, this study aims to investigate the effect of punch force, sheared surface, and work hardening by using commercially pure titanium sheets. The punching process under the study employed three different punch geometries, namely flat (FLAT), single shear angle (SSA) and double shear angle (DSA) with a shear angle of 17°, while the Punch velocity used was 35mm/s and 70 mm/s. The results show that the punching process using SSA and DSA punch geometry with the punch velocity of 35 mm/s reduces the punch force by 18% and 13% consecutively compared to that of FLAT with the same velocity. However, the sheared surface quality seems to decline as the rollover height increases by about 48% and 32%. Moreover, the burnish height decreases by 34% and 7% and the resulted work hardening improves by 4.7% and 2.3% respectively. The study concludes that SSA and DSA punch geometry can be best used to reduce punch force and increase work hardening, but apparently fail in increasing the sheared surface quality.

Effect of punch velocity on punch force and burnish height of punched holes in punching procces of pure titanium sheet

Punch velocity is one of the important parameters in the punching process. The choice of punch velocity is difficult because it has a different influence on each material. Therefore, it is important to know the effect of punch velocity on the material to be worked. The purpose of this study was to investigate the punch velocity effect on punch force and burnish height of the punched holes in the punching process of pure titanium sheets. The punching process used was a pneumatic punch machine with punch velocity of 10, 35, 70 mm/s. The result shows that when punch velocity of 10, 35, 70 mm/s, punch force that occurred each by 357, 408 and 434 N. Burnish height resulted by 0.194, 0.200 and 0.241 respectively. Its indicates that punch velocity affected on punch force and burnish height of punch holes. When punch velocity increased, punch force and burnish height of the punched holes increased.

Effects of punch velocity on microstructure and tensile properties of thixoforged Mg2Sip/AM60B composite

Abstract The effects of punch velocity on the microstructures and tensile properties of Mg2Sip/AM60B composite were investigated. In comparison, the tensile properties of the permanent mold casting of this composite were also analyzed. The results indicate that the punch velocity obviously influences the microstructure through changing the secondary solidification behaviors and semisolid deformation mechanisms. The variations of the microstructures and deformation mechanisms are responsible for the changes in tensile properties and fracture modes of the composites. The best comprehensive tensile properties of this composite are obtained under the punch velocity of 60 mm/s. The resulting ultimate tensile strength and elongation of the composite are found to be 198 MPa and 10.2%, respectively. The excellent tensile properties of the thixoforged composite are ascribed to the elimination of porosities and the work hardening.

Modelling the Belt Perforation Process with the Piercing Punch and the Die in the Context of the Construction of the Punching Dies

Proper usage of modelling in the design process should result in achieving the effective construction of the machine. However, the methodology of modelling should be adjusted to the specific application. This paper presents the algorithm of modelling the belt perforation process. Authors show the main aspects that should be taken into consideration during the design process of punching dies. Important correlations between construction, process and exploitation parameters are described along with the analysis methods. The main focus of the paper is put on the geometry of the piercing punch, which can significantly change perforation force, tool life and hole quality when it is modified. The paper also analyses the impact of punch velocity and temperature on the force necessary to pierce the material. Additionally, the methodology of determining the mechanical properties of the belt used for further modelling is discussed.

Effect of Preheating on Punch Force, Sheared Surface and Work Hardening in Cold Punching Process of Commercially Pure Titanium Sheet

In cold punching, the main problems are the large punch force and the low burnish in sheared surface; otherwise, the main problem in warm and hot punching is the decrease in material hardness. Therefore, cold punching with preheating has been developed in order to reduce the punch force and to improve the burnish height. This paper aims to investigate the effect of preheating in the cold punching on punch force and burnish height of commercially pure titanium. The testing apparatus used has been a pneumatic punch machine with temperatures of 30, 100 and 150 °C. Punch velocity used has been 35 and 70 mm/s. The results show that cold punching with preheating can reduce punch force, improve burnish height, and decrease work hardening. With a preheating of 150 °C on velocity 35 mm/s, punch force has been reduced by 17.8% compared to cold punching force. On the other hand, burnish height has improved by 41.6%; this result is smaller than warm and hot punching. However, the ratio of burnish height resulted to thickness is greater. Work hardening has decreased by 27% of cold punching work hardening; this decrease is smaller than warm and hot punching.

An extrusion simulation of an aluminum profile by porthole die

The aluminum alloys are ideal material because of their corrosion resistance, recycling ability, high specific strength and especially low density for lightweight structures of transportation, aerospace, automotive industries. Hot extrusion process is the most used metal forming method for obtaining a variety of aluminum alloy profiles. The demand for large cross section, multi cavity and thin wall profiles has been increasing with the development of the industry and extrusion method is key solution for producing complex profiles with high productivity. These profiles are generally extruded by porthole dies. The extrusion process by porthole die is complicated and die design has great importance for the quality of the extruded product. Design of the porthole die should give optimum material flow and homogenous temperature distribution both for obtaining desired profile and eliminating die scrap. The measuring the temperature and material flow is not possible for closed die formation and it is so important to estimate both material flow, temperature change in the die. For this aim, an extrusion simulation of a porthole die for standard aluminum profile was investigated in this study with the support of HyperXtrude Inspire Extrude Metal 2019 software, which is specialized for FEM calculations of extrusion process. Each step of extrusion process was simulated. Aluminum AA6063 material was used for simulations, the process temperature was 4500 °C and punch velocity was selected as 5 mm/sec. Finally, the FEM results were obtained and the temperature distribution, pressure distribution, billet interface and relative die exit speed results were analyzed.

Establishment of an in-situ small punch test method for characterizing hydrogen embrittlement behaviors under hydrogen gas environments and new influencing factor

The hydrogen embrittlement (HE) behaviors of structural materials used to handle hydrogen must be tested at their use environments. In this study, an in-situ small punch (SP) test method was established to characterize HE behaviors of SA372 and STS304 steels under hydrogen gas environments at high pressures and low temperatures. In addition, a new influencing factor, relative reduction of thickness (RRT) was proposed to quantify the HE sensitivity of structural steels. Under 10 MPa H2 gas environment, load-displacement curves obtained and fractographic morphologies of the recovered specimens were analyzed to investigate the HE behaviors based on punch velocity and test temperature. When the HE sensitivity was evaluated by RRT, STS304 steel appeared to be vulnerable to HE as compared to SA372 steel across the tested temperature range. As a result, it was found that in-situ SP test and RRT can be used to quantify the HE sensitivity for structural materials screening regardless of test environments.

Analysis of friction behaviour under oscillating forming process using T-shape compression test and finite element simulation

Frictional behaviour under oscillation-assisted forming was studied by the newly designed vibrating T-shape compression test under continuous re-lubrication condition. The friction factor in the oscillating bulk forming was identified from the inverse approach by iteratively calibrating the simulated deformed shape parameters to the experimental values. To increase the prediction accuracy of material response during oscillating motion of material, the elastic-plastic friction law and nonlinear elastic unloading and reloading behaviour in addition to the strain-rate dependent constitutive law were implemented in the finite element simulations for oscillating T-shape compression tests. Comparative sensitivity analyses were provided to study the influences of material model and oscillation parameters such as frequency, amplitude, and velocity of tool motions on the frictional behaviour. The present study shows that the reduction of friction factor in the oscillating forming can be explained by the continuous change of elastic recovery during the plastic deformation of workpiece and by the re-lubricated interface during the vibrational motion. The simulation can provide quantitative analyses for the effects of oscillation frequency, amplitude and punch velocity on the friction factor, which can be utilized for efficient process optimization of oscillation-assisted forming technology.

Variations of Energy Demand With Process Parameters in Cylindrical Drawing of Stainless Steel

Studies have indicated that reducing the process energy demand is as important as improving the energy conversion efficiency to make manufacturing equipment more energy efficient. However, little work has been done to understand the energy demand characteristics of the widely employed drawing process. In this paper, the energy demand of the cylindrical drawing process under a range of operating parameters was measured and analyzed. Since any energy saving efforts should not have negative effects on the product quality, the forming quality of the drawn part indicated by the maximum thinning and thickening ratios and variation of thickness was also considered. To identify the main contributors to energy demand and forming quality, two sets of experiments were designed based on the Taguchi method. The first set of experiments include three parameters (i.e., punch velocity, blank holder force, and drawn depth) at three levels, while the second set of experiments only include two factors (i.e., punch velocity and blank holder force) at three levels due to their impacts on the forming quality. Analysis of variance (ANOVA) and analysis of means (ANOM) were then used to analyze the experimental results. Finally, grey relational analysis (GRA) was used to reveal the correlation between the forming quality and the process energy. Results show that the mean thickness variation has the strongest relational grading with the process energy, which suggests that the process energy can be used as an effective indicator to predict mean thickness variation of the drawn part. The identified characteristics of the process energy and the forming quality can be used to select process parameters for reduced energy demands of drawing processes.

A forming load analysis for extrusion process of AZ31 magnesium

Abstract The effect of extrusion parameters on the extrusion load for AZ31 magnesium alloy was investigated with the support of numerical methods. With this regard, the process temperature, extrusion ratio, friction factor and punch velocity were selected as main parameters for the experiments. Besides, the experimental results were analyzed by using the finite element method (FEM) and artificial neural network (ANN) method to build a numerical model for predicting the forming load. All the experimental and numerical results were compared to each other and it was concluded from the results that the effect of friction factor on the extrusion load is more dominant at lower extrusion temperature for all given extrusion ratios and punch velocities. Besides this, higher extrusion ratios require higher process temperatures to obtain the lower extrusion load. Also, it was observed that the increase in the extrusion speed causes a significant increase in the forming load for all extrusion ratios and extrusion temperatures.

Thixoforming of Wrought Aluminum Alloy 1973

In this paper, the microstructure and mechanical properties of thixoformed 1973 (AlZn5.5Mg2.4Cu1.7Zr) wrought aluminium alloy were investigated. A cooling slope was used to produce non-dendritic billets. Thixoforming process parameters were determined as follows: die temperature of 250 °C, feedstock temperature of 600 - 605 °C, punch velocity of 7 mm/s. Mechanical properties of thixoformed with ultimate strength of 461 MPa and elongation of 3,1 % in the T2 condition. The lower properties of the thixoformed material are mainly associated with porosity.

Multi parameter optimization of deep drawing for cylindrical cup formation on brass sheets using Grey Relational Analysis

Abstract Deep drawing is the widely used process for producing products from sheet metals. There are many effectible process parameters in the process. Proper selection of these parameters leads to sound forming of the components. The aim of the present paper is to analyze the influences of the forming parameters in deep drawing process on the outcomes like drawing force and thinning ratio in cylindrical cup forming of brass sheets. Three Control parameters are considered in the present study such as blank diameter, punch velocity and lubricant with three levels each. The experiment is conducted according Taguchi's DOE methodology and experimental data is analysed by using Taguchi Grey Relational analysis Method for the identification of optimal process parameters. The optimal values are confirmed and found that it is satisfactory. The ANOVA analysis also conducted to determine the influences of control parameters.

Load path modelling in single-step deep drawing of rotationally symmetric cups

Abstract The reduction of material usage through damage control in metal forming processes provides the potential for cost reduction. The evolution of damage during metal forming processes has been shown to depend on the evolution of equivalent stress, stress triaxiality and the Lode parameter. However, the investigation of stress states does require numerical modelling of the forming process, for example using the Finite Element Method (FEM). From these models, load paths with regard to stresses, strains and temperatures can be extracted. Such load paths represent the evolution of the respective variable during the forming process. To control damage in deep drawing, the prevalent load paths have to be modified. Aside from variation of the process parameters, such as punch velocity, die geometry and temperature, specific process setups can be used to achieve tailored load paths. Numeric simulation of a single-step deep drawing process creates a basis to modify load paths through process variations such as multi-step deep drawing and reverse deep drawing.

Simulation and numerical analysis of warm stamping (AA6061)

Abstract Stamping process is an important sheet metal forming process used in domestic and automotive components. In this process, blank material is converted into the desired complicated shape by punching process.Stamping includes a process such as punching using a punch or ram, blanking, embossing, bending, flanging, and coining.Cost minimisation ,less time consumption, increase in efficiency are very important in the recent manufacturing industry. Today simulation techniques are used to analyse the performing of dies, processes and billets prior to real timeimplementation. Simulations enable us to find out the common defects such as tears, wrinkles, and material thinning. Finite element analysis (FEA) is the method of simulating the process of sheet metal forming to determine various behaviour of the sheet metal and helps us to find out whether it will produce parts free of defects such as fracture or wrinkling. Sheet metal forming is a popularly used metal working process. In this paper stamping process is analysed numerically using a simulation software package LSTC – LSDYNA. A three dimensional thermo-mechanically coupled stamping model is analysed and its validations are presented. The analysis data from the numerical simulation helps in understanding the real-time mechanism of sheet metal forming process.There areonly few works were reported on numerical analysis of warm stamping of AA6061 such as load requirement, blank holder pressure, stress-strain analysis.This work is based on study the deformation behaviour of sheet metal, flow stress analysis, contact pressure and punch velocity.

Thixoforming of Hypereutectic AlSi12Cu2NiMg Automotive Pistons

The microstructure and mechanical properties of thixoformed AlSi12Cu2NiMg (AЛ25) aluminium alloy were investigated. Cooling slope method was employed in order to produce non-dendritic billets. Thixoforming process parameters were determined as follows: die temperature of 250 °C, billet temperature of 555 - 560 °C, punch velocity of 7 mm/s. Mechanical properties of automotive piston with ultimate strength of 309 MPa, yield strength of 274 MPa and elongation of 6.8 % in the T6 condition were obtained successfully, implying success of advantages of cooling slope method.

Understanding Compression-Induced Amorphization of Crystalline Posaconazole.

Process-induced phase transformations (PIPTs) of active pharmaceutical ingredients (APIs) can alter APIs' physicochemical properties and impact performance of pharmaceutical drug products. In this study, we investigated compression-induced amorphization of crystalline posaconazole (POSA), where the impact of mechanical stresses and excipients on amorphization were explored. 19F solid-state NMR (ssNMR) was utilized to detect and quantify amorphous content in the compressed tablets, and finite element analysis (FEA) was conducted to understand stress distributions in the compression process. Both applied macroscopic axial stress and shear stress were found to be important to amorphization of crystalline POSA. Punch velocity, an important compression process parameter, had negligible effect on amorphization up to 100 mm/s. Two diluents, microcrystalline cellulose (MCC) and dibasic calcium phosphate anhydrous (DCPA), and one lubricant, magnesium stearate (MgSt), were evaluated for their impact on amorphization in this study. It was found that both MCC and DCPA significantly enhanced amorphization of POSA at a low drug loading (5% w/w). The 1% (w/w) blended lubricant effectively reduced the amorphous content in MCC-POSA tablets; however, it had minimal effect on either neat POSA or DCPA-POSA tablets. Drug loading, or excipient concentration, was demonstrated to have a significant impact on the extent of amorphization. These observed excipient effects support the important role of interparticulate stresses in amorphization of crystalline POSA.

Transient thermo-electro-elastic contact analysis of a sliding punch acting on a functionally graded piezoelectric strip under non-Fourier heat conduction

Within the framework of the non-Fourier heat conduction law, this paper presents a transient, frictional thermal analysis with heat generated by a sliding punch acting on the surface of a functionally graded piezoelectric strip (FGPS). A continuous variation in the thickness direction is adopted for the material properties of the piezoelectric strip. By using the Laplace and Fourier integral transform techniques and the superposition principle, general solutions of the thermal field, and homogeneous solutions for both real and complex eigenvalues and particular solutions for the electro-elastic field are given. Results in the time-domain are obtained by applying the numerical Laplace-transform inversion method, and the convergence behavior is analyzed. Numerical results demonstrate that the thermal relaxation effect makes the results of the non-Fourier heat conduction model reach their peak values later than those of the Fourier model. The effects of the punch velocity, the friction coefficient, and various gradient parameters on the contact stress and the surface heat flow are revealed in details.