Papers by Keyword: Deep Drawing

Abstract: Due to the development of corrosion-resistant lightweight, todays automotive manufacturers typically use zinc coated sheet metals in the forming process. However, zinc abrasion in industrial presses decreases the process stability and often causes interruption of the whole process. The application of high strength steels leads to a significant increase of the temperature due to the plastic work. So far a detailed, quantitative analysis of the relation between temperature and zinc abrasion is not available. Therefore, this paper examines the impact of the temperature on abrasion behaviour in sheet metal processes. To achieve this, a progressive die was built. The deep drawing stage of this tool is connected to a cooling / heating system in order to obtain a constant temperature during the forming process. A variety of different galvanized sheet metals compared to commonly used tool materials has been tested. For each combination of materials five experiments at different temperatures were performed to determine the effect of the temperature on the zinc abrasion. Applying the method of total reflection x-ray fluorescence (TXRF) the quantity of zinc abrasion was measured. A relation between low temperatures and reduced zinc abrasion can be clearly observed. Industrial experiments revealed that temperature exerts a high influence on the zinc abrasion. The new insights into the impact of the temperature show a significant way to lower the zinc abrasion and therefore increase the process stability in deep drawing processes.

Abstract: This paper presents a fully automatic parameter classification procedure in order to identify the most influencing parameters together with locally interesting parts of the component considered in a certain processing step. The results of this classification approach are used for a parameter space reduction in order to minimize the computational effort for subsequent analysis and optimization tasks based on forecast models. In particular, an outlook on the evaluation of radial basis function metamodels for a robust parameter identification is given. We demonstrate the classification procedure and its benefits by an industrially relevant deep drawing process of a pan with secondary design elements.

Abstract: This paper presents results from application of discrete state spacebased feedback control of the blank holder force (BHF) magnitude and distribution in the drawing ofa rectangular workpiece. By means of monitoring the flange draw-in during the punch stroke, the controller makes continuousadjustments to the BHF magnitude and distribution by individuallycontrolling the pressure of a hydraulic fluid in a number of cavitiesembedded in the blank holder plate. The adjustments are conducted onlineduring the punch stroke to minimize the deviation of the achieved flange draw-in from a predetermined reference.

Abstract: For enhance the heating efficiency and the formability of the magnesium alloy and aluminium matrix composite sheets, pulse current is adopted to the gas bulging and stamping processes. During the bulging process of magnesium alloy sheet, the effects of dynamic pulse current on the formed sheet combine both thermoelectricity and electro-plasticity. The effect and the applicability of the pulse current heating have been evaluated. The deformation properties, microstructure characteristics, and dislocation movement of the AZ31 alloy sheet during bulging process by the resistance heating are investigated. And the resistance heating has been adopted to improve the formability of SiC_p/2024Al composites in stamping process. The pulse current density achieved 21.7A/mm² and temperature of SiC_p/2024Al composite correspondingly reached to around 400°C in the 50s. The results showed that stainless steel inserts between sheet and copper electrodes successfully prevented the heat dissipation and promote temperature uniformity over the sheet during electrifying. In addition, workpiece formed by the pulse current deep drawing shows better shape retention, surface quality and high geometry dimensional accuracy.

Abstract: For the complex shape and difficult forming of engine oil filer shell, this paper aims to do research on stamping technology and mold of engine oil filer shell. Based on the calculation and analysis of the forming technology according to its characteristics,the forming process is optimized, which includes 6 steps: blanking and drawing, re-drawing, 3rd-drawing, reshaping, beading and trimming, punching and flanging. Then for the importance of multi-drawing process, the numerical simulation of the multi-drawing process has been carried out by using the Dynaform software. The results show that the good piece of the oil filter shell can be drawn from sheet material through the 6 steps one by one. Finally, according to the results the molds are designed.

Abstract: Axisymmetrical hemispherical pieces belong, in considering plate thickness variation of normal anisotropy, hardening and friction, BHF on the basis of various factors such as the establishment of the different stages of the forming process of the mechanical model of the deformation zone is derived the calculation equation, the preparation process, the process for drawing the stress-strain state and the shape of the part thickness distribution for a complete numerical analysis.

Abstract: Tensile tests and a cold deep drawing process were developed at room temperature to estimate the stamping formability of AZ31B magnesium alloy sheet. The results show that AZ31B magnesium alloy sheet has poor formability at room temperature with the total elongation of ~ 20%, the yield ratio is about 0.6 and the strain-hardening exponent is 0.18, while the plastic strain ratio is 1.58, and the earing ratio is-0.55.Thus, AZ31B magnesium alloy sheet can not suffer server plastic deformation. It was found that comparatively shallow magnesium alloy cups were satisfactorily formed at room temperature without heating when the punch fillet radius 6mm and the die fillet radius10mm with a 1mm thickness sheet with limit drawing ratio of 1.25.

Abstract: This paper presents simulation of drawing force and thickness deformation in deep drawing which employs semi-active blank holder force system, to solve the problem of cracking and wrinkling. The method of slab with feed back control failure criteria, was employed to make the modeling system and the semi-active blank holder to prevent wrinkling and cracking in forming low carbon steel sheet, without lubrication (μ=0.4). In this study, the mechanical properties of the material were chosen since that they equivalent to those of low carbon steel with its thickness of 0.2 mm, k = 572 N/mm², UTS = 391 N/mm², yield stress = 309 N/mm² and n = 0.2. The diameter and the depth of the cylindrical cup-shaped product were 40 mm and 10 mm, respectively. Results from simulation have shown that the semi-active blank holder system can control very responsive against changing of deformation condition. The optimum of initial blank holder force is approximately 3000 N up to 4000 N. In the early stages (initial stroke), blank holder force system could be responsive to prevent cracking, and at the end of the punch stroke, it is very effective to prevent wrinkling. Simulation of semi-active blank holder force control system is excellent in model formation to prevent cracking and wrinkling.

Abstract: Manufacturing of beverage cans is porcessed by using multi-stage ironing following deep drawing from the sheet material of aluminum and steel. An earing profiles are develops during deep drawing of cylindrical cup due to the planar anisotropic properties of sheet. Therefore, the analysis of earing is important to evaluate and control the development of earing. This paper describes a simulation of the cold ironing process in the forming cylinder cap. The ironing process in this study was focused on the prediction of height increasing, earing and thinning. Two different materials of aluminum AA5042 and AKDQ steel were selected for comparison. The results show that the increasing of cup height was in the same trend.

Abstract: Deep drawing involves conversion of flat thin sheet metal blanks into parts of desired shape. In the present investigation, the process parameters of warm forming are compared with those of Hydromechanical deep drawing. Warm deep drawing process of circular blanks in Ironing stage is investigated using a 20 T hydraulic press. Hydro-mechanical deep drawing is a process for producing cup shaped components with the assistance of a pressurized fluid. There is an increase in the drawability of low Carbon steel by increasing the oil gap (gap between punch and die) but to make exactly cylindrical shape, the cup is subjected to ironing in the later part of drawing operation. Thickness distribution which describes the quality of the drawn cup is compared in both warm and Hydromechanical deep drawing using experiments and finite element simulations. Keywords- Warm forming,Hydromechanical, deep drawing, Drawability.