Die Roll Height Research Articles

Experimental Investigation of Process Forces and Part Quality for Fine Blanking of Stainless Steel with Inductive Heating

Fine blanking is a highly productive process of industrial mass production with which high quality components in particular but not exclusively for the automotive industry are produced. The manufacturing process faces its limits at elevated tensile strengths of the materials to be processed. Consequently, high-strength steels can currently only be fine blanked to a limited extent. This can be overcome by lowering the flow stress of high-strength steels by means of inductive heating. A steel of high importance especially for industries with high hygiene standards such as medical and nutrition production is the stainless steel X5CrNi18-10 (1.4301). As a metastable austenitic steel which can initiate cutting impact on the press through martensitization, fine blanking of stainless steel is a challenge. X5CrNi18-10 is not a high-strength steel per se but becomes difficult to process due to the high hardness of the martensite phase, known as transformation-induced plasticity (TRIP) effect. Thus, in order to combine the possible advantages of the fine blanking process with inductive heating and the important properties of stainless steel, fine blanking of this steel was investigated with inductive heating prior to the fine blanking. The process forces and product quality properties such as die roll were investigated and found to be advantageous in comparison to non-heated fine blanking specimens of the same steel. The process forces and the die roll height decreased due to the heating.

Reduction of die roll height in duplex gears through a sheet-bulk metal forming method

In the existing shearing processes for fabricating parts such as duplex gears, die roll is difficult to avoid. Accordingly, a method based on sheet-bulk metal forming for fabricating a duplex gear with extremely small die roll in one stroke is proposed in the current work. The process could be divided into three stages according to the forming features: upsetting and shearing stage, lateral extrusion stage, and local filling stage. The die roll appeared in the shearing stage, which could be reduced in the subsequent extrusion and local filling stages. To reveal the underground mechanism, material flows under two situations, as a key factor to influence the forming quality, were compared and investigated. The results revealed that by controlling material flow, one could avoid the defects and reduce the die roll.

Comprehensive prediction method for die-roll height of fine-blanking components

This study proposes an economic and effective approach for predicting the die-roll height of fine-blanking components by fully considering the effect of three types of parameters: geometric features of components, process parameters of fine-blanking, and material parameters of fine-blanked sheets. Two prediction submodels that involved geometric features and process parameters individually were established based on a back-propagation artificial neural network (BP ANN), merged into one model, and finally generalised to different materials by correction according to experimental results. During modelling, simulations rather than experiments were used to obtain data for supporting BP ANN considering the demand for a single controlling variable and for saving economic and time costs. Analyses showed that geometric features had a more distinct influence on die-roll height; furthermore, the effect of process parameters is complicated and can be described more suitably by BP ANN. The prediction results of the combined model were favourable compared with the experimental results. Furthermore, the experimental curve used for correction during generalisation of the model showed that a material with higher yield strength generally had smaller die-roll.

A predictive model for die roll height in fine blanking using machine learning methods

A method for the development of a predictive model for the die roll height in fine blanking using artificial neural networks and support vector machines is presented. Since artificial neural networks require big amounts of training data and generation using experiments is very time consuming and cost intensive, a validated FE model is used instead. The required training data will be determined using learning curves. The optimal architecture and hyperparameter of the artificial neural network will be derived. Additionally, the die roll height is modelled using support vector machines and also conventional statistical regression models. Finally the accuracy of the methods is compared.

Dependencies of the die-roll height during fine blanking of case hardening steel 16MnCr5 without V-ring using a nesting strategy

For economic reasons, fine blanking of asymmetric parts is performed with shifted and rotated part nesting. It was observed that both the part position and the part orientation on the sheet metal strip affect the die-roll height. Therefore, the influence of the bridge width between the produced cutting line and the strip edge or existing sheared edges was studied in this work. Additionally, the effects of the stroke number, the convexity of the radii and the sheet metal anisotropy were considered. The parts were manufactured in a production series of 40,000 parts with a fine blanking tool ejecting four parts simultaneously. From each nest, 20 parts were separated at four equidistant steps. The die-roll height was determined in three regions with different convexity radii of parts from varying nests. A normal distribution was found for the die-roll height, categorized by convexity radius and position of the nest. The die-roll height was found to be promoted by convexity radius, small bridge width, and in transverse blank direction. The number of strokes had a minor impact. Interaction effects occur particularly at small convexity radii and small bridge widths. As a conclusion, the nesting must be considered in order to reduce the die-roll height. Small bridge widths, small convexity radii, and the orientation in transverse blank direction have a negative impact, whereas the stroke number has a marginal influence. The understanding of the correlation between die-roll formation and nesting helps to reduce waste in mass manufacturing.

A Study Of The Die Roll Height Of SHP-1 And SCP-1 Materials In The Fine Blanking Process

Abstract The height of the die roll, the distance of the V-ring, and the shear rate were varied with the aim of investigating the effects of the applied changes on the fine blanking line in a cold-rolled and a pickled steel sheet, referred to as SCP-1 and SHP-1, respectively. Both materials consisted primarily of a ferrite phase with small amounts of impurities including F, Mn, and Cr. The distance was found to be a very important factor in controlling the shear of the V-ring in the fine blanking process. When the position of the V-ring was set at distances of 1.5 mm and 2 mm, the die roll height increased with increasing shear speeds from 6.4 m/min to 10 and 16 m/min. Analysis of the influence of the shear rate revealed that low rates resulted in the lowest die roll heights since the flow of material was effectively inhibited.

An Experimental Study on the Effect of Die Chamfer Shape and V-Ring Position on Die Roll Height in the Fine Blanking of a Special Part with Various Corner Shapes

In this paper, a change of die roll height according to the die chamfer shape and V-ring distance of a fine blanking tool was studied by experiments on a special part with various corner shapes. Three guide plate inserts with different V-ring positions and three die inserts with different die chamfers were machined, and then a fine blanking tool was manufactured for the fine blanking experiments. Nine experiments were conducted on a 650-ton fine blanking press. Each die roll height was measured and analyzed. It would be noticed that the die roll heights on the corner shapes of the fine blanked parts increased with increasing V-ring distance and die chamfer angle, but it decreased with increasing corner radius and angle. The results in this study can be used to minimize the die roll height of fine blanked parts with corner shapes when designing the V-ring and die chamfer of a fine blanking tool.

An Experimental Study on the Die Roll Height According to the V-Ring Distance of the Fine Blanking Tool for the Seat Recliner Holder with Various Corner Shapes

In this paper, the relation between die roll height and V-ring distance of a fine blanking tool was studied by experimenting on a special designed seat recliner holder with various corner shapes. Three guide plate inserts with different V-ring distances and a die insert with constant die chamfer were machined, and a fine blanking tool was manufactured for the experiments. Three experiments were conducted on a 650-ton fine blanking press. Each die roll height on the sample from the experiments was measured and analyzed. It should be noticed that the die roll heights on the corner shapes of fine blanked parts increase with increasing the distance between the V-ring distance, and decrease with increasing corner radius and angle. These results can be used to minimize the die roll height of fine blanking parts with corner shapes when designing the V-ring of a fine blanking tool.

An Experimental Study of V-Ring Position on the Die Roll Height in the Fine Blanking of Special Part with Corner Shapes

In this paper, the relation between die roll height and V-ring position of a fine blanking tool was studied by experimenting on a special part with various corner shapes. Three guide plate inserts with different V-ring positions and a die insert with constant die chamfer were machined, and a fine blanking tool was manufactured for the fine blanking experiments. Three experiments were conducted on a 650-ton fine blanking press. Each die roll height was measured and analyzed. We found the tendency of the die roll heights on the corner shapes of fine blanked parts to increase with increasing the distance between the V-ring position and the contour of the special part, and to decrease with increasing corner radius and angle. These results can be used to minimize the die roll height of fine blanking parts with corner shapes when designing the V-ring of a fine blanking tool.

파인 블랭킹 금형의 V-링 위치 및 다이 챔퍼 형상이 다이 롤 높이에 미치는 영향에 관한 실험 연구

기어의 파인 블랭킹에서 기능면으로 사용되는 전단면(잇 면)을 최대한 확보하기 위하여 다이 롤 높이(die roll height)의 최소화는 매우 중요하다. 본 논문에서는 파인 블랭킹 금형의 핵심 설계 요소인 V-링 위치와 다이 챔퍼 (die chamfer) 형상에 따라 기어의 다이 롤 높이 변화를 고찰하기 위하여 V-링 거리와 다이 챔퍼 형상이 다른 여러 가지 다이 편 및 가이드 플레이트 편으로 구성된 파인 블랭킹 금형 세트를 제작하여 실험하였다. 각 실험으로부터 시 편을 채취하여 다이 롤 높이를 측정 분석한 결과 파인 블랭킹 기어의 다이 롤 높이는 각 모듈에서 다이 챔퍼 각도가 증가함에 따라 증가하고 V-링 거리가 증가함에 따라 증가됨을 알 수 있었다.

A Study on the Effect of V-Ring Position on the Die Roll Height in Fine Blanking for Special Automobile Seat Recliner Gear

In this paper, the relation between die roll height and V-ring position was studied by fine blanking experiments for imaginary special automobile seat recliner gear. The three die inserts and three guide plate inserts with different V-ring positions were machined, and fine blanking tool was manufactured. Using the fine blanking tool, three experiments were conducted on the 650 ton fine blanking press. Each die roll height was measured, analyzed and we found the tendency of die roll heights on imaginary special gear to increase with increasing the distance between V-ring position and contour of gear. This result can be used to minimize the die roll height of fine blanking gear parts when designing V-ring of fine blanking tool.

A Study on Die Roll Height of Special Automobile Seat Recliner Gear According to Die Chamfer Shape in Fine Blanking Tool

In this paper, the effect of die chamfer shape on the die roll height was studied by fine blanking experiments for imaginary special automobile seat recliner gear. The three die inserts with different die chamfer shapes were machined, and fine blanking tool was manufactured. Using the fine blanking tool, three experiments were conducted on the 650 ton fine blanking press. Each die roll height was measured, analyzed and we found the tendency of die roll heights on imaginary special automobile seat recliner gear to increase with increasing die chamfer angle, with the horizontal distance of die chamfer being constant. This result can be used to minimize the die roll height of fine blanking gear parts when designing die chamfer of fine blanking tool.

A Study on the Relation between Die Roll Height and Die Chamfer Shape in Fine Blanking for Special Gear

In this paper, the relation between die roll height and die chamfer shape was studied by fine blanking experiments for imaginary special gear. The three die inserts with different die chamfer shapes were machined, and fine blanking tool was manufactured. Using the fine blanking tool, three experiments were conducted on the 650 ton fine blanking press. Each die roll height was measured, analyzed and we found the tendency of die roll heights on imaginary special gear to increase with increasing die chamfer angle, with the horizontal distance of die chamfer being constant. This result can be used to minimize the die roll height of fine blanking gear parts when designing die chamfer of fine blanking tool.

Application of Fine Blanking to the Manufacture of a Sprocket with Stainless Steel Sheet

Wire cutting(EDM) or blanking is used to made workpieces from sheet metal. Wire EDM provides a relatively simple method for making holes of any desired cross section in material. But EDM requires a lot of working time and the high unit cost of production. In conventional blanking, for the production of precision devices or assemblies, it is always necessary that at least two, but generally more, secondary operations are required per piece part. Using the fine blanking process, a precise finished part with inner and outer forms clearly sheared over the whole material thickness are produced in one single operation. In this study an attempt is made to manufacture a sprocket with fine blanking process. The sprocket is parts for the tape feeder of surface mount system in electronic parts. First, a change of the existing design is made in a sprocket. The materials selected are three kinds of stainless steel, SUS304, SUS316 and SUS430. And the mechanical properties are investigated through the tensile test. After fine blanking, hardness and precision are examined with hardness test and 3-dimensional coordinate measuring for samples. The results of investigations of fine-blanking process with the help of FEM code, DEFORM 2D, are presented. For the simulation, SUS304 and SUS316 are used as materials. The damage model of Cockroft and Latham is used to calculate damage. Die-roll height, die-roll width, burnish zone and fracture zone from the fine blanking simulation are investigated in comparison with them of samples. And the applied force at each part of fine-blanking die is estimated with load-stroke diagram.

The effects of tool geometry change on shearing edge finish in fine-blanking of different materials

An excellent quality of shearing edge implies that a smooth cutting edge without tearing will be observed on the whole edge surface. This is one of the most significant features of the fine-blanking process. To achieve this good blanking edge quality in fine-blanking, quite a large number of factors need to be considered simultaneously during the operation, such as blanking speed, processing material, product shape, lubrication and tool geometry. Thus, the objective of this paper is mainly to study the influence of tool geometry change in fine-blanking for different materials. This is because the nose radius usually seriously deteriorates with increasing service period in mass production, which eventually causes the entire loss of the specific features of the fine-blanking process. Therefore, a tailor-made experimental study was carried out to investigate the relationship between the punch nose radius and the shearing edge quality, such as the shearing edge surface finish, burr height and die-roll height, during fine-blanking for different types of materials. Consequently, findings show that an increase in the punch nose radius produces a higher percentage of fracture of the blanked edge and increases the amount of burr height.