Papers by Keyword: Fine Blanking

Abstract: In fine blanking, a mass production process for safety-critical components, a discrepancy exists between deterministic modeling approaches and the stochastic nature of real-world measurements, often termed process noise. This work combines Finite Element Method simulations with data from industrial-scale fine blanking experiments, featuring long stroke series across multiple coils with systematically varied die clearances. The analysis shows a strong correlation between force curve characteristics and the formation of tears, a relationship that holds across all tested geometries. In contrast, only weak and inconsistent correlations were found between the force signal and the resulting die roll. This weakness is explained by the finding that multiple physical effects, such as material strength and friction, have competing influences on die roll that are not separable in the single force signal. These results demonstrate that the utility of the force signal for quality prediction is highly dependent on the tool geometry, providing a basis for more reliable tool design strategies in fine blanking.

Abstract: A fine blanking (FB) has grown up as a manufacturing means to fabricate the precise automotive parts from the thick sheet metals. During this net-shaping process, each part product had fully burnished surfaces through a single stroke. The punch for this FB, were highly loaded enough to distort the punch edge and to deteriorate the cost competitiveness and sustainability. A chamfered SKH51 tool steel punch was designed by controlling the chamfer widths and angles. A massively nitrogen supersaturated SKH51 punch was also prepared to investigate its effect on the suppression of punch edge distortion. AISI304 stainless steel work was used to describe the variation of punch distortion and blank qualities with increasing the number of strokes.

Abstract: Fine blanking is a key technology for the near-net-shape production of sheet metal components. It is often used in combination with processes such as deep drawing. With increasing environmental requirements, the processing of materials with lightweight construction potential is becoming more and more important. A group of materials with high potential for lightweight construction, not only due to their suitability for hot stamping, is the group of manganese-boron steels. The fine blanking properties of these steels have not yet been exhaustively investigated. In this work, the fine blanking properties of the manganese-boron steel 40MnB4 were investigated in comparison to the quenched and tempered steel 42CrMo4. This was done using a star-piece fine blanking layout with investigation of die roll as well as tooth tip cracking. Furthermore, an investigation of the high-temperature fine blanking properties were investigated by means of inductive heating prior to fine blanking. The process forces were evaluated depending on the sheet metal temperature. A good fine blanking capability of 40MnB4 could be confirmed. Process forces and product quality were comparable to 42CrMo4 steel. Accordingly, an industrial application of fine blanking to manganese-boron steels seems highly promising.

Abstract: Fine blanking is a production technology of high importance especially for the automotive industry. As a procedure of sheet metal separation, it is possible to produce complex parts in a single stroke. As a difference to conventional punching, the cutting surface of fine blanked parts can often be used as a functional surface without further process steps. However, fine blanking as a forming process changes the microstructure of the metal sheet to a higher extend than cutting or machining processes. Due to this, it is of utmost importance to investigate the cause-effect-relations between the fine blanking process parameters and the resulting properties of the fine blanked part. Especially the condition of the cut surface as an important quality criterion has to be investigated. The quality characteristics of the cut surface of fine blanked parts are often subject of investigations. In addition, it would be of importance to investigate how the material properties in the shear zone are changed by the fine blanking process. This on one hand in turn can enable conclusions to be drawn about possible punch wear. If, on the other hand, hardening of the cut surface takes place as a result of fine blanking, then this could have a positive influence on the application properties of fine blanked components. Thus, an experimental fine blanking investigation of the micro hardness of the cutting surface has been made with variation of steel material and cutting temperature. It could be demonstrated that the micro hardness increases in direction towards the burr. This is independent on material and cutting temperature.

Abstract: The aim of this study was to investigate the influence of laser surface texturing on fatigue life and tribological properties. Textures were introduced before and after hard TiAlN coating deposition in order to investigate the sequence of surface texturing process. It was found that the sequence of surface texturing has an effect on tribological and fatigue life behaviour. If laser texturing is done after coating deposition, friction is lower because of the better wettability of steel in comparison with coating, but suffers in fatigue life properties.

Abstract: This paper proposes a new blankholder to fine blanking process. V-ring indenter has been widely applied in fine blanking to produce clean cut parts, however, it is difficult to be manufactured, the machining accuracy of which is hard to ensure and the cost is very high. In this approach, the fine blanking process combined with discontinuous dot indenter was put forward and the parameters design for workpiece with different thickness was studied with the finite element simulation and the orthogonal experiment methods. The larger burnished surface zone can be obtained by optimizing discontinuous dot indenter parameters. In addition, the relationship between the discontinuous dot indenter parameters and the workpiece thickness was got from data processing. Finally, applying this relationship to fine blank workpiece with different thickness, nearly full clean cut surface part was obtained.

Abstract: Front cover is an important part of the car timing system, it is also an important parts of the engine to ensure the smooth flow.The quality of end cap is directly related to the normal and efficient operation of the engine.In this paper, through the research of the fine blanking process of the front cover of the timing system, a new type of fine blanking die is designed to improve the service life of the die and its parts.The influence rules of the process parameters such as the back top force, the counter pressure and the corner radius on punching smooth zone and the life of the mold, are analyzed by using the finite element software and a series of optimized process parameters are obtained after this.

Abstract: Heat treatment is one of the major sources of dimensional inaccuracy in the manufacturing of fine blanked parts. Tools and equipment often need to be iteratively corrected in order to achieve the desired quality. Numerical simulation of the heat treatment process can substantially reduce these efforts. The simulation accuracy on the other hand is strongly dependent on the accurate characterization of the thermo-mechanical boundary conditions as well as material properties. The present contribution aims to propose a novel approach in the calibration of numerical models by using a modified Jominy test as well as heat treatment experiments with parts having residual stresses from a bending process. The results are validated by comparing numerical phase content and hardness values with the corresponding experiments.

Abstract: Fine blanking is a widely used process that permits the production of precise finished components which are cleanly sheared through the whole cutting surface. It can be eliminated secondary operations, such as milling, grinding, etc. Many studies on the weight reduction of automobile for fuel saving were underway. The clearance of the punch-die of a fine blanking tool is an important design factor that affects the sheared surface of a product. If the clearance is too big, a fractured surface would occur in the product while if it is too small, bulging would occur. The main objective of this paper is to provide an overview of the effect of clearance between punch and die in a fine blanking tool on quality of sheared surface. A well as to specify the effect of mechanical properties of sheared steel sheet on blanked edge quality given by ratio of h_v/a_0.

Abstract: Scar formation in fine blanking was investigated by means of a particularly developed fine blanking tool and experimental evidence about significant the process parameters chamfer size of the blanking tools, V-Ring usage and clearance is given. Furthermore, a special purpose Finite Element code using the Arbitrary-Lagrange-Eulerian method with a process specific mesh generation is demonstrated and used for the determination of relevant parameters for prediction crack formation in 3D fine blanking simulations. The simulations shown, that a commonly used description of fracture strain as a function of stress and deformation state is not sufficient. In order to simulate scar occurrence on the blanking surface, the significant increase of fracture strain due to temperature rise because of plastic heat generation has to be taken into account. A possible way of measuring the temperature effect was shown in torsion tests at different initial temperature levels.