Fine Blanking Process Research Articles

Analysis of some aspects of fine blanking process

Blanking is one of the advanced technologies of processing materials and manufacturing products. Simple cutting is affected by the uneven action of plastic deformation. This makes the cut surface irregular. Blanking methods have been improved and new technologies in the process of blanking have been developed. Using these technologies we easier achieve higher geometric precision and surface quality. One of these technologies is fine-blanking. The aim this of study was to investigate the mechanical properties of the material and verify the suitability of the material for the production of parts made by fine blanking and analyze the failure of ejector tool. Based on the tests performed we can conclude that material DN-C45 (12045) is not suitable for the production components made by fine blanking technology. For production of parts, we recommend to use the material C45 in modification GKZ-EW – soft annealing, fine cold rolled with globular pearlite, tensile strength 480 MPa, yield strength of 290 MPa and hardness maximum 150 HB. Based on documented microscopic breaches at ejector in etching state, we see that oxidation occurs at the point at the breach. In the present case for the assessment of cracks on the ejector, it is necessary to consider whether the thermal process was adhered.

Numerical Investigation of Fine Blanking of a Helical Gear

Fine blanking, as an effective and economy metal forming process, can be used for the manufacturing of helical gears with inclined forming movement. In the present study, a reliable three-dimensional (3D) rigid-plastic finite element (FE) model is developed on the DEFORM-3D platform for rotational fine blanking of a helical gear. Based on this FE model, distributions of different field variables such as metal flow velocity, mean stress and effective strain are obtained, and cut surface features and punch stroke curve are predicted. The results achieved in this study can not only evaluate the capabilities of the rotational fine blanking process of a helical gear, but also provide valuable guidelines and a better understanding of the deformation mechanism of this process.

Back propagation neural network based calculation model for predicting wear of fine-blanking die during its whole lifetime

Die wear during fine-blanking process greatly influences the lifetime of die as well as the quality of products. It is a known fact that wear of die is nonlinearly related to blanking times during its whole service life. To illustrate this phenomenon effectively and precisely, a calculation model for predicting wear of fine-blanking die during its whole lifetime was established based on Back Propagation (BP) Neural Network, Finite Element Method (FEM) and experiments. The inherent law between wear of fine-blanking die and its working parameters was revealed by utilizing the BP neural network. Based on the obtained function and the variation of the working parameters, a calculation model was established to predict die wear at any blanking times during fine-blanking process. To verify the efficiency and validity of the proposed calculation model, a fine-blanked part was utilized in this paper. Tool wear of the bottom die was investigated. Pressure-pad force, ejector force, blanking speed, blanking clearance, fillet radius of bottom and hardness of bottom die were specified to be the key process parameters contributing to the wear condition of bottom die. The process parameters’ coupled influence on die wear during fine-blanking process was obtained by a trained neural network. And the die–wear-curve predicted by the calculation model is in good agreement with the real manufacture, which confirms the validity of the proposed BP neural network based calculation model.

The Study of the Relation between Clearance and Fine-Blanking Quality

a numerical model research of fine-blanking has been built up. The fine-blanking process of parts with clearance 0.1%S, 0.7%S, and 1.3%S. (S stands for the thickness of the material) respectively, thickness of plate 2.9mm and diameter 16mm of steel 45, has been simulated. Through simulation, the study gets the material distribution situation of mean-stress fields in the progress of fine-blanking, and the author analyzes the relation between mean-stress fields and the crack of shearing zone. Through analysis the author concluded that the section quality grows with decrease of blanking clearance.

Forming Force Analysis in Fine-Blanking Process by Experimental Approach and Analytical Formulation

Large deformation is a major deformation operation in many metal-forming processes, such as forging, rolling, extrusion, stamping and fine-blanking. It is difficult to study the deformation changes in these processes in a practical way, through the measurement of forces, due to the severe and localized nature of plastic deformation such as in the fine-blanking operation. Therefore, the forces analysis of most metal-forming processes cannot be carried out successfully by experiments. Thus, this paper aims to present the development of an effective process of forces measurement in fine-blanking process. Also, the effect of blank geometry and material properties on forming force in fine-blanking process was studied by theoretical formulation and experimental approach. Tensile strength and initial blank thickness were considered in this research. The obtained results indicated that by increasing the initial blank thickness and the tensile strength, the forces in fine-blanking process is increased.

CAE를 이용한 파인블랭킹 성형 해석

Computer-aided engineering (CAE) is the broad usage of computer software to aid in engineering tasks. It includes computer-aided design (CAD), computer-aided analysis (CAA), computer-integrated manufacturing (CIM), computer-aided manufacturing (CAM), material requirements planning (MRP), and computer-aided planning (CAP). In this study, the stress of mold analyzed using CAE technique. Punch loads were same difference between 0.5 % and 1.0 % of clearance, but punch load was decreased according to increasing of clearance. Punch load of pre-piercing process worked a little smaller than piercing process. Therefore, the hole of fine blanking process is also more efficient to manufacture the true size after pre-piercing.

Research on the Shrinkage Cavity Defect of the Extruded Boss in Fine Blanking Process

The shrinkage cavity defect of the extruded boss is harmful to the quality of fine blanking workpiece and process. To suppress the shrinkage cavity defect, firstly, the boss extrusion is simulated to analyze main features of metal flow and the causes of the shrinkage cavity defects; secondly, some parameters affecting the material flow, such as the size of die and punch, blank holder force, friction coefficient, sheet thickness and counter force, are studied to figure out their influences on the depth of shrinkage cavities respectively; finally, the process parameters of a special workpiece are selected according to research results above, and experiment verified that the selected parameters can suppress the shrinkage cavity defect pertinently. In the paper, the shrinkage cavity defect is systematically studied for the first time, and this provides the base to design and optimize the extruded boss feature in fine blanking process.

Investigation of Die Wear during Fine-Blanking Process of a Kind of Automobile Synchronizer Slipper by FEM and Experiments

In this paper, die wear during fine-blanking process of a kind of automobile synchronizer slipper was investigated based on Finite Element Method (FEM) and experiments. The Finite Element (FE) model to simulate the fine-blanking process of the automobile synchronizer slipper was established on the DEFORM-3D software platform, and Archard's wear model was employed to calculate die wear during the process. Meanwhile, mesh refinement and automatic remeshing technique were used during meshing process of the blanked materials and bottom die in order to achieve high accuracy results of FE simulations and improve the computational efficiency. Simulation results have been verified and show good agreement with the real manufacture. In addition, relationships between die wear and the process parameters during fine-blanking process such as pressure pad force, ejector force, blanking speed, blanking clearance, fillet radius of bottom die as well as hardness of bottom die were investigated, respectively via FEM. The simulation results indicate that die wear is in proportion to the pressure pad force, ejector force, blanking speed and fillet radius of bottom die, while in inverse proportion to the blanking clearance and hardness of bottom die, which will provide a reliable reference for the real manufacture and engineering application.

Improving wear resistance of sprocket parts using a fine-blanking process

A sprocket is a toothed wheel, commonly used in drive systems, to which the strength and wear resistance of the teeth are important. Sprockets are conventionally fashioned by hobbing, followed by heat treatment. However, the fine-blanking process has recently seen increasing use by sprocket manufacturers. The process of fine-blanking has the possibility of reducing the number of process operations, thus reducing production time and cost, as well as improving part quality and process repeatability. Because of the severe plastic deformation in fine-blanking process, the strength, hardness and wear resistance of parts can be improved. In this work, the surface hardness and wear resistance of a fine-blanked sprocket are compared with those of a sprocket made using the hobbing process. The source of the wear resistance improvement was identified via examination of the microstructure. The microstructure of the fine-blanked sprocket revealed an increasingly compressed and elongated grain structure, in which grain flow and orientation resulted in pronounced hardening across the tooth width. The wear resistance of the fine-blanked sprocket, as measured by the distance between the teeth and the radius at the tooth bottom, was greater than that of the hobbed and heat-treated sprocket. Based on the results, the material cost of the sprocket could be reduced by using low carbon steel (SS400) instead of medium carbon steel (S50C), and further savings in production time would be realized by eliminating the need for subsequent heat treatment.

3D Numerical Simulation and Optimization of Processing Parameters in Fine Blanking of Back Plate of Brake

Due to the limitation of 2D simulation in fine blanking, finite element software DEFORM-3D was used to simulate the 3D model of Back Plate. In this article the Normalized Cockroft&Latham fracture criterion was chosen to simulate the blanking process. The distribution and developing trend of the hydrostatic stress, equivalent stress in the fine blanking process are predicted. When the die radii are between 0.4mm and 0.6mm, burnished surface improves. It shows that the ideal blanking clearance value is 0.6% of the material thickness. The results indicate that FE numerical simulation could effectively optimize fine blanking process and offer basis for quality improvement.

로어투스의 롤오버 및 금형 면압 저감을 위한 하프블랭킹 공정 설계

In recent years, automotive seat components have been manufactured by the fine blanking process, allowing an improvement of dimensional accuracy at sheared surface in series production. However, the rollover has increased and die failures have occurred more frequently when manufacturing gears by fine blanking. Consequently, important goals for manufacturing seat recliner parts with gears have been to decrease the rollover as well as to improve the tool life. In this study, the half blanking and shaving processes were introduced to improve aforementioned problems for the lower tooth, the main component of a seat recliner. For this purpose, the half blanking process was optimized using the finite element (FE) analysis and design of experiment (DOE). The optimized conditions resulting from this study were an offset of 0.2 mm, a clearance of 0.1 mm and a penetration depth of 4.5 mm. Fine blanking experiment conducted under the optimal condition resulted in a rollover depth decrease from 1.9 to 1.3 mm, and no die failure occurrence.

Modelling of Fine Blanking Process of the Aluminium Sheets

The required technological quality of the blanked products can be achieved through operations of fine blanking. This allows for obtaining products with improved dimensional accuracy and good quality cut-surface. In order to cut products from soft materials, including aluminium and its alloys, the methods of fine blanking with upsetting and fine blanking with reduced clearance are typically employed. The study presents the results of numerical modelling of the fine blanking process for a disk made of 1-millimetre sheet aluminium EN AW-1070A. The goal of the numerical simulations was to evaluate the effect of clearance between blanking die and the punch, and the impact of V-ring indenter on stress and strain distribution in the shearing zone.

Surface fatigue and wear of PVD coated punches during fine blanking operation

Performance of two different physical vapour deposited (PVD) TiCN and Alcrona® (AlCrN) coatings systems is under investigation. Coatings were deposited on the punches produced from the Böhler S390 Microclean steel. Two different surface preparation techniques were used – wet polishing (high surface roughness) and dry polishing (low surface roughness). Industrial trials of PVD coated punches in fine blanking operation were performed and studied. Wear of punches was analysed in regard to the punch geometry, position in the die and surface roughness, and measured after maximum 100,000 cycles at high loads. Punches with higher surface roughness seem to withstand numerous loading cycles with some traces of coating delamination and wear. On the other hand performance of PVD coatings with smaller surface roughness in a striking way was much worse. Comparative trials of the coatings surface fatigue wear and indentation surface fatigue testing were performed in the laboratory as well. In surface fatigue wear testing coatings were dynamically indented by ball (spherical) indenters made from conventional hardmetal (WC-6 wt.%). Testing parameters were identical to those of industrial trials. The Vickers diamond pyramid indenter was cyclically pressed with 500 N load at single point during indentation surface fatigue testing. Results are in agreement with surface fatigue wear tests results. Finally the microstructural investigations using SEM and XRD techniques were performed for better understanding of the surface fatigue and wear mechanisms during fine blanking process. Results of both trials are in good agreement and allow predicting performance of coatings.

Effect of shape of workpiece on forming force in fine blanking process

Fine blanking produces smooth sheared edges over the full workpiece thickness in a single operation allowing the required cutting edge quality and dimensional accuracy to be obtained without secondary machining. There are various parameters with different adjustment levels, affecting the fine blanking surface. In this paper, the effect of the shape of workpiece on forming force in fine blanking process was studied by theoretical formulation and experimental approach. Two workpieces with the same thickness and different shapes were considered in this research. The theoretical formulation was used as a tool to carry out the predication of fine blanking force. The obtained results indicated that by increasing the shape of the workpiece, the forces in fine blanking process are increased.

Research on influence of material properties and blank geometry on forming force in fine blanking process

Fine blanking produces smooth sheared edges over the full workpiece thickness in a single operation allowing the required cut edge quality and dimensional accuracy to be obtained without secondary machining. There are various parameters with different adjustment levels, affecting the fine blanking surface. In this study, the effect of blank geometry and material properties on forming force in the fine blanking process was studied by the theoretical formulation and an experimental approach. Tensile strength and initial blank thickness were considered in this research. The results obtained indicate that by increasing initial blank thickness and tensile strength, forces in fine blanking process are increased.

Research on Flow Mechanism of Materials and Micro-State of Distortion Area in Closed Extruding Fine Blanking Process

There are some differences between traditional fine blanking and closed extruding fine blanking in stress, separation process and change of material's performance. The article researched the micro-state's characteristics and deformation law in closed extruding fine blanking process, through observing the closed extruding fine blanking parts' metallographic, flow lines of deformation zone and analyzing the micro-hardness.

Analysis of Shear Droop on Cut Surface of High-Tensile-Strength Steel in Fine-Blanking Process

The fine-blanking process is used in the production of automobile parts and other metal components. Although the fine-blanking process can produce sheared surfaces with higher precision than the punching process, shear droops on cut surfaces are also formed, as in the punching process. It is important to determine the causes of the formation of shear droops, but the mechanism is difficult to determine experimentally. Here, the finite element method (FEM) is adopted to study the causes of the formation of shear droops. The cut surfaces in the present experiments have fine sheared surfaces but no fracture surfaces. Although a combination of the fracture criterion and element-kill method is used for many simulations of the fine-blanking process, fine sheared surfaces cannot be evaluated by the combination of these methods. In the present calculations, an adaptive remeshing technique for FEM is used to create fine sheared surfaces. The shear droop is associated with the initial compression by and the subsequent clearance of the punches and dies. Results are obtained for various clearances and initial compressions in the fine-blanking process for high-strength steel, and the experimental and calculation results are compared. In the present paper, we show that the shear droops are affected by the clearance of and initial compression by the punches and die. [doi:10.2320/matertrans.P-M2010828]

Numerical Simulation of the Fine Blanking Process of Sheet Titanium

Numerical Simulation of the Fine Blanking Process of Sheet Titanium

FEM and ANN Analysis in Fine-Blanking Process

Fine-blanking (FB) is an effective and economical shearing process that offers a precise and clean cutting-edge finish, eliminates unnecessary secondary operations, and increases quality. In the traditional blanking product development paradigm, the design of the formed product and tooling is usually based on know-how and experience, which are generally obtained through long years of apprenticeship and skilled craftsmanship. In this study, the possibility of using finite element method (FEM) together with artificial neural networks (ANN) was investigated to analysis the fine-blanking process. Finite element analysis was used to simulate the process with an isotropic elastic–plastic material model. The results compare well with experimental results available in the literature; after confirming the validity of the model with experimental data, a number of parameters such as V-ring height effect, punch and holder force on die-roll, hydrostatic pressure status as an important factor in increasing burnish zone, and accuracy of part and radial stress status as a factor in increasing die erosion, which were also used for training the ANN, were considered. Finally, numerical data were used to train neural networks. The Levenberg–Marquardt (LM) algorithm with three neurons in the hidden layer (LM-3) appeared to be the most optimal topology and gives the best results. It was found that the coefficient of multiple determinations (R 2 value) between the FEM and ANN predicted data is equal to about 0.999 for the size of die-roll, therefore indicating the possibility of FEM and ANN as a powerful design tool for the fine-blanking process.

Application of Back-Up Ring in Fine-Blanking Process

Considering the advantages of the fine-blanking process, the smooth-cut surface without further operation could be fabricated. However, one of the major problems of the fine-blanking is the occurrence of the die-roll formation. This problem is the main factor which affects the quality of the fine-blanked parts. In this study, to reduce the amount of die-roll formation, the application of back-up ring was proposed. The finite element method (FEM) was used to investigate the effects of back-up ring. In addition, the effects of bridge width were also investigated. The FEM simulation results illustrated that the mechanism of back-up ring and the effects of bridge width could be theoretically clarified base on the material flow analysis. The FEM simulation and experimental results showed the good agreement with each other. Therefore, the application of back-up ring could reduce the amount of die-roll formation on the fine-blanked parts. In this study, the amount of die-roll formation increased as the bridge width increase and it was constant at the bridge width of over 15 mm.