In the production process of metal products, metal forming technology plays a crucial role. Among them, sheet metal processing is a common metal forming method, which covers a variety of processes such as metal deep drawing and metal stamping. Metal deep drawing is the process of stretching the sheet through the deep drawing die to form the desired shape, while metal stamping is the process of using the stamping die to pressurize the sheet to achieve the molding of the product.
The metal composite plate combines the different properties of the group element metals and has good comprehensive performance. Composite plate in the production, especially in the deep drawing process, due to the lack of theory and experience to guide, will face some molding defects problems, such as single-layer rupture, whole-layer rupture, wrinkles and so on. Composite plate deep drawing forming is affected by many factors, such as concave mold fillet radius, convex-concave die clearance, and the depth of the mold.
Diameter, convex-concave die clearance, crimping force, deep drawing speed, etc., the selection of reasonable process parameters can obtain better forming quality, improve the service life of the mold, improve the economic efficiency of enterprises.
Improve the economic efficiency of the enterprise. Composite plate is a new type of material, the deep drawing process parameters on the
The impact of deep drawing process parameters on the molding results is less studied. In this paper, we mainly investigate the key technical problems in the numerical simulation of deep drawing of stainless steel/aluminum/non-inductive steel three-layer composite plate, and take Φ14 cm×9 cm pot as the object to study the effects of concave die radius, convex-concave die clearance, crimping force, deep drawing speed on the maximum thinning rate of the composite plate.
To study the influence of die radius, die clearance, pressing force and deep drawing speed on the maximum thinning rate of composite plate, and to optimize these 4 process parameters by orthogonal test, which provides reference for the actual production of the factory.1 Key technology in numerical simulation of deep drawing of composite plate
1.1 Composite plate layer to layer connection processing
The studied three-layer composite plate material and thickness of the three layers are: 430 stainless steel (0.6 mm) + 1050 aluminum (1.8 mm) + 304 stainless steel (0.4 mm), the total thickness of 2.8 mm. 430 stainless steel has a magnetic conductivity, as the outer layer of the parts, which can be used for induction heating; 430 stainless steel has a good corrosion resistance, as the inner layer of the parts; core layer 1050 aluminum has good thermal conductivity. In the numerical simulation of the composite plate, the connection between the layers of the composite plate and the layers is the key to the numerical simulation. In Abaqus/CAE, there is a special composite plate modeling and design module Composites Layup, for each ply, you can select the ply application area, the use of materials, angle, thickness, etc.; post-processing module, you can display each ply into the thickness direction of the stress, displacement, etc., cloud diagrams, but also display the composite plate thickness direction of the variable change curve [10], so the use of Layup ply connection is the key to numerical simulation. Therefore, the Layup layup connection method is used to deal with the stainless steel/aluminum/stainless steel
The connection of three-layer composite plate. In the setup, a shell unit layer is created first, and then the Layup module is utilized to set the required number of layers and give material properties to each layer.
1.2 Comparison of modeling methods for composite plates
From the macroscopic point of view, the composite plate can be regarded as a whole, and from the microscopic point of view, it can be regarded as a superposition of layers with different material properties.
From a macroscopic point of view, the composite plate can be regarded as a whole, and from a microscopic point of view, it can be regarded as a superposition of layers with different material properties.
One is the whole model, and the other is the composite plate model. The overall model is the three-layer composite plate equivalent to the same material material, modeling as a single-layer plate, and give the overall mechanical property parameters. In the composite plate model, a single-layer shell unit is established, and then in the material model, a single-layer shell unit is established.
block, the material property parameters of each layer structure are entered sequentially in accordance with the order of layups. The above two methods are modeled and numerically simulated, and the simulation results are compared with the thickness as the evaluation index, and the accuracy of the two models is judged according to the experimental results.
3 Optimization of deep drawing and forming process parameters Object of study
That is, the optimal process parameters of Φ14 cm×9 cm pot 3.1 Determination of orthogonal experimental scheme The orthogonal experiments take four process parameters as optimization variables, namely, stamping speed, crimping force, radius of concave and concave die radii, and gap between convex and concave dies, and take the maximum reduction rate as the optimization target. Numerical simulation and analysis are carried out using four factors and four levels, and the levels of each factor are determined according to the results of single-factor simulation and analysis: concave die radius r: 12, 15, 18, 21 mm; concave/concave die clearance Z: 3.2, 3.3, 3.4, 3.5 mm; crimping force F: 50, 83, 116, 149 kN; and deep-drawing speed v: 10, 20, 30, 40 mm/s. 3.2 Orthogonal experimental results and analysis of four factors and four levels of 16 groups of orthogonal experimental results of the maximum thinning rate.3.2.1 Analysis of variance Due to the influence of a variety of factors, the data of the study exists in the volatility of the fluctuations, the cause of the fluctuations may be an uncontrollable random factor, or the study of the imposition of the results of the formation of the fluctuations may not be controlled.
controlled factors imposed in the study that form an impact on the results [11]. In order to investigate whether the previous results are caused by random errors or by variations in the forming parameters and which parameters have a significant effect on the forming results, the results of the orthogonal tests are now subjected to analysis of variance (ANOVA). The ANOVA table for maximum thinning rate is shown in Table 4. Comparing the mean square MS and the mean square of error e in Table 4, it can be seen that the mean square MS of each factor is greater than the mean square of error e, which indicates that the differences in the orthogonal test data are mainly caused by changes in the factors; and comparing the F value with the critical value of F, if the F value is greater than the critical value, it indicates that the factor has a significant effect on the molding results, otherwise, it is not significant on the molding results. The effect of concave mold fillet radius and crimping force on the maximum thinning rate is significant. In addition, comparing the corresponding F values of each process parameter, it can be seen that the order of the influence of each process parameter on the maximum thinning rate is as follows: concave die radius > crimping force > convex-concave die clearance > deep drawing speed.