Study of Deep Drawing Process Parameters: A Review

Deep drawing process has been an important manufacturing process to produce automotive parts of good strength and light weight. There are many process parameters and other factors that affect product quality produced by deep drawing. This paper is highlighting recent research work and results in deep drawing. Deep-drawing operations are performed to produce a light weight, high strength, low density, and corrosion resistible product. These requirements will increase tendency of wrinkling and other failure defects in the product. Parameters like as blank-holder pressure, punch radius, die radius, material properties, and coefficient of friction affect deep drawing process. So a great knowledge of process is required to produce product with minimum defects. This review paper has given the attention to gather recent development and research work in the area of deep drawing. Sheet-metal forming processes are technologically among the most important metalworking processes. Products made by sheet- forming process include a very large variety of different geometrical shapes and sizes, like simple bend to double curvatures even with deep recesses and very complex shapes. Typical examples are automobile bodies, aircraft panels, appliance bodies, kitchen utensils and beverage cans. Sheet-metal forming processes are widely used in the manufacturing industry. It is usually involved in developing and building tools namely die and punch. Usually, tools are costly and the cycle time for building them is long. However, once die and punch are built, the tools can be used to produce a large amount of products. Therefore, sheet-metal forming is a simple and efficient manufacturing process. Great productivity and low production cost can be expected for commercial scale production. As mentioned that the flat sheet of metal is formed into a 3-D product by deep drawing process. The basic tools of the deep drawing process are blank, punch, die and blank holder (or pressure plate). Deep drawing is affected by many factors such as material properties, tool geometry, lubrication etc. Because of these factors, some failures may occur during the process. Tearing, necking, wrinkling, earing and poor surface appearance are the main failure types that can be seen in deep drawing. Tearing and necking are caused by the tensile stresses and they are types of tensile instabilities. Another failure is wrinkling, caused by compressive stresses unlike to tearing and necking. When the radial drawing stress exceeds a certain value compressive stress in the circumferential direction becomes too high, so plastic buckling occurs. The four major defects which can occur during deep drawing are fracture, wrinkling, earing and spring back .The phenomenon of wrinkling (flange instability) is specific to the process of deep-drawing . Instability in the work piece, also called wrinkling of the walls. In deep drawing process the main objectives are to obtain defect less or minimum defects in product. Prediction of wrinkling is a very important process for a deep-drawing operation. Because a part wrinkled during the deep drawing process will not be accepted and most likely become as scrap. The factors affect the deep drawing process may be categorized into three categories. (i) Process parameters (ii) Geometrical Parameters (iii) Machine parameters Process parameters include blank holder force, coefficient of friction, drawing ratio, material properties. Geometrical parameters include blank diameter, cup diameter, blank thickness, and corner radii of cup. Machine parameters include die radius and punch radius. To achieve a successful deep drawing process, a study of the stress-strain and anisotropy behaviour of the sheet metal to be used is inevitable. Before one begins to study the stress-strain and anisotropy behaviour in sheet metals, a proper knowledge of the stresses that occur during the forming process needs to be established.