A New Incremental Sheet Forming Process Based on a Flexible Supporting Die System

Developments in deep drawing of welded sheet metals over the past 15 years

Deep Drawing (DD) process is the one in which a punch forces a flat sheet metal blank into a die cavity. DD can also be described as the process which involves conversion of flat thin sheet metal blanks into parts of desired shape. Little work is available in the applications of DD processes at elevated temperatures which is going to be a very important manufacturing application in the coming decades. Deep Drawing (DD) is one of the sheet metal forming processes widely used in automobile, aerospace, electronics and allied industries to produce the hollow parts. The improvement in the deep drawing manufacturing process with latest methodologies leads to developments in the automobile and other sheet metal industries. Still today, this process of analysis and design is an art than science. Presently, the conventional deep drawing (CDD) operation is carried out at room temperature in industries. Although the deep drawing process of high strength / low formability metals has an extensive industrial application area, deep drawing at room temperature has serious difficulties because of the large amount of deformations revealed and high flow stresses of the materials. The present paper gives an overview of deep drawing process, its classification along with advantages, limitations and applications.

laser shock forming, which combines the metal forming and material modification, is a non-mode, flexible forming new technology using laser-induced force effect of high amplitude shock waves to obtain the plastic deformation of sheet metal. in this paper, the simulation of laser shock forming process of tc4 sheet metal was carried out through the commercial finite element analysis software abaqus. the influence of the sheet thickness, laser energy, constraints aperture and laser spot spacing on the sheet metal deformation are investigated. the results show that: with the increase of sheet thickness, the deformation range of sheet decreases, and the amplitude of deformation decreases firstly and then increases. the deformation increases linearly with the increase of laser energy. the larger boundary constraint aperture leads to the larger deformation of sheet metal. there are no obvious influence on the forming accuracy when an opposite laser spot spacing is adopted. therefore, under the condition of meeting the accuracy requirement, for improving the efficiency, adopting a certain laser spot spacing to finish the forming should be considered.

The principle of NC incremental sheet metal forming as well as the process planning, experiment of sphere forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to shear deformation and thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. According to sine law, a sphere can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. Thus, the two time path process method is presented to form the sphere, and the experiment is made to verify it. A sphere can be formed from a sheet metal in NC incremental forming process by choosing appropriate tool-path planning. The fracture in the forming component can be avoided by these methods. A sphere of uniform wall-thickness can be formed from the truncated cone by NC incremental forming process.

Measuring deformation mostly is based on the contact type of measurements which utilize the gauges and instruments. But this type of contact will lead to error in the precise measurement because of errors by the contact, measuring instruments, and human. So, feel proud to introduce image processing in the field of measurement. Here, in this study deals the measurement of deformation of deep drawing specimen by image processing which is called as contact free method. This is invasive method of measurement in two dimensions.Deep drawing process is an important sheet metal forming in which flat sheet metal had been forced through the die in association with the forward punch force and opposing blank holder force. As the blank passes through the tool set converts 2D bank into 3D cup formation. The process of achieving the required diameter of the cup can be produced in single stage or multistage operation. In this study, experimental study had been conducted on single stage deep drawing process for assessment of deformation and strain in aluminum alloy, copper alloy and brass alloy. Cylindrical cup deep drawing experimental tests were performed with blank of 60 x 60 square plate with 1 mm thickness. Eventually this new approach will help to optimize the geometry parameters deep drawing specimen correlation with the Matlab results.

We present the results of application of a physical criterion of yield in the complex stress-strain state to the description of plastic deformation at the crack tip. Unlike the von Mises criterion, the proposed criterion enables one to take into account the characteristics of plastic deformation of bcc metals at low temperatures. We simulated the process of loading of a platelike specimen (400×1600 mm) containing a central crack under conditions of plane deformation. It is shown that the drop of shear resistance under the action of normal tensile stresses observed in the process of low-temperature plastic deformation of bcc metals and alloys strongly affects the parameters of the stress-strain state of the metal at the crack tip. Thus, it leads to the enlargement of the zone of local plastic strains, promotes an increase in the maximum level of plastic strains at the crack tip, and affects the relationship between the tangential and normal stresses in the plastic zone. It is demonstrated that the physical criterion of yield can be efficiently used for the numerical analysis of the stress-strain state at the crack tip in bcc metals and alloys at low temperatures by the finite-element method.

A Generalized Kinematics Model for Three- to Five-Axis Milling Machines and Their Implementation in a CNC

Shortened product development processes in automotive industry combined with the upcoming lack of experts do challenge sheet metal part production fundamentally. Tryout time and manufacturing costs of large forming dies today are significantly influenced by their digitally supported engineering. The forming process by such tools is beside other influences is affected by elastic deformations of forming dies and press structure as well as contact areas between die and sheet metal part. In deep drawing such contact areas are influenced by the blank properties and the flange behavior in terms of thickening and thinning. Recent developments in sheet metal forming simulation do consider advanced friction models and structural modeling of die and press components improving simulation accuracy. Nevertheless thinning or thickening of sheet metal results into localized surface pressure distribution during deep drawing. For this reason, it is not sufficient to use the currently common practice of homogeneous surface pressure distribution in sheet metal forming simulation. In this respect, this paper presents a numerical approach for consideration of straining effects in the sheet metal part during forming operation. For this purpose, a systematic process improvement was developed in this paper to identify contact areas via a numeric simulation parameter. Validating the numerical investigation, a rectangle cup die is used, considering major strain. The main results of this contribution for that reason show how simulated contact areas can be estimated by reverse engineering of real forming parts. Hereby straining based contact areas lead to a novel contact area design in process planning, resulting in efficient die tryout.

Know-how on mechanical behaviour of sheet metal forming operations like deep drawing etc., are very much essential for quality production of articles having wide industrial and domestic applications such as automobile, beverage, aerospace and kitchenware. A variety of forming tests are available for evaluating sheet metal deformation properties and proper selection of quality tests is very much essential in this regard. By thorough understanding of these tests, indeed, helps the craft-man to select suitable forming tools and material parameters for producing components without rejections and at low cost. This paper highlights the concept on different formability tests that are commonly used industry.

On the basis of an upper bound yield function, a rigid–plastic mesodamage constitutive theory for through thickness anisotropic and planar isotropic sheet metals with voids is established. This theory provides a solid foundation for the analysis of plastic deformation and damage evolution in sheet metals under forming. In addition, the physical quantities defined in this theory make it possible for engineers to predict precisely and control optimally the influence of microvoids and through thickness anisotropy on the mechanical properties and forming limits of sheet metals.

Series production of sheet metal components in press shops is permanently subjected to an increasing pressure in time, cost and quality. Varying sheet metal properties due to batch fluctuations and changing process conditions lead to an increase of try out time phase and scrap rate, resulting in a demand for adaptive control strategies for deep drawing. Today, these chal-lenges are met by integrating sensors and actuators into tool structure which measure and control part quality, mainly through blank draw-in. However, such tool-based control systems require a complex and cost-intensive modification of the existing die or press technology. Against this background, the active adjustment of blank position prior the deep drawing process realized with an intelligent transfer and positioning system as a promising approach towards economic and technical aspects. This paper deals with blank positioning and its sensitivity to quality-related failures of deep drawn sheet metal components like splits and wrinkles. Therefore, a numerical study was conducted on a deep drawing process of an exemplary structural part geometry, wherein a typical fluctuation of material parameters and variation of local friction conditions was simulated. Subsequently, correlations between process disturbance and blank draw-in were elaborated, thus using local draw-in values as controlled variables for a closed loop system. Sim-ulation results showed that the manipulating parameter, i.e. the blank position prior deep draw-ing, reveals a significant influence on the draw-in and therefore on the component s quality. An essential finding of this study is the numerical proof of concept for this new deep drawing control strategy, demonstrated for different process conditions. Finally, disturbances in the deep drawing process considered could be successfully controlled by adapting the blank position.

Cross-profile deep drawing of magnesium alloy AZ31 sheet metal for springback analysis under various temperatures

Static recrystallization simulations starting from predicted deformation microstructure by coupling multi-phase-field method and finite element method based on crystal plasticity

Industrial CNC machine tools are supplied as closed architecture systems. Their structure, kinematics and CNC controllers are designed to be used exclusively for their basic purpose, without any possibility of being changed. Reconfiguration is seen as the ability to add or remove modules from the machine, to be equipped with additional degrees of freedom (axes). For the concept to become a reality, it is necessary that the machine tool can be easily assembled and disassembled by an end-user and can adapt to changing projects or machining requirements. The approached of this research was to develop a 5-axis modular machine tool, with technological capabilities similar to industrial ones, at an affordable level of development costs and suitable to be used for teaching CAM techniques for future engineers.

Deformation Behaviors of Laser Forming of Ring Sheet Metals