A method of pre-treating a mould profile

Abstract

The application provides a mold surface preprocessing method, which comprises the following steps: designing a 3D mold structure based on a mold surface of an original product, modeling the mold structure together with a production machine bed surface in a finite element analysis software by meshing, performing a loading deformation CAE analysis, outputting deformation vector field data of an upper model surface of the original product, generating reverse deformation vector field data based on the deformation vector field data, performing reverse deformation on the upper model surface of the original product according to the reverse deformation vector field data, obtaining an upper model surface after reverse deformation compensation, performing formability analysis on the upper model surface of the original product in the CAE analysis software, obtaining thinning vector field data of each position of the part after forming, taking the upper model surface after reverse deformation compensation as a reference, performing unequal gap offsetting on a lower model surface of the original product according to the thinning vector field data and a material thickness of the part, and obtaining a lower model surface after reverse compensation. The application can effectively improve the matching rate of a mold surface.

Description

Technical Field

[0001] This invention belongs to the field of mold technology, and specifically relates to a mold surface pretreatment method. Background Technology

[0002] The fitting rate of the mold surface for vehicle exterior body panels refers to the accuracy of the closing gap between the upper and lower molds. It is generally measured by applying indigo paint to the workpiece in this process of the mold, and then applying pressure to the mold using a machine tool. The percentage of the indigo paint that is removed by the mold is called the mold fitting rate. The fitting rate ensures uniform and precise closing of the gaps between different parts of the mold surface. Only when the mold is properly fitted and the gaps between different parts are uniform can the workpiece be completely pressed and compacted by the mold.

[0003] However, due to the inevitable thinning of parts during the forming process, the thickness of the formed product differs from the theoretical value due to the different shapes of various areas. Traditional molds, with the gap between the upper and lower mold surfaces offset according to the theoretical material thickness, result in gaps between the upper and lower molds in localized areas when forming is complete, preventing coloring. Furthermore, since the press table and mold body structure are actually non-rigid structures, they inevitably undergo elastic deformation under load, causing changes in the gap between the convex and concave mold surfaces, preventing complete fit with the part. The larger deformation in the middle area of ​​the mold structure easily leads to a "hollow" fit phenomenon. Both of these reasons result in a low fit rate of the mold surfaces for outer cover parts, causing the produced parts to not fit the mold properly, easily leading to various forming problems such as waves, bulges, and depressions. Mold fitters need to manually grind and adjust the fit rate of the mold surfaces, resulting in a heavy workload, time-consuming and labor-intensive process, and a long debugging cycle. Therefore, how to design a mold surface pretreatment method to effectively improve the fit rate of the mold surfaces has become a technical problem urgently needing to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a mold surface pretreatment method to solve the above-mentioned technical problems in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for pre-processing mold surfaces, comprising the following steps:

[0007] Step S1: Design a 3D mold structure based on the mold surface of the original product, and mesh and model the mold structure together with the production machine tool table in the finite element analysis software.

[0008] Step S2: Perform loading deformation CAE analysis and output the deformation vector domain data of the model surface of the original product;

[0009] Step S3: Generate reverse deformation vector domain data based on the deformation vector domain data. Based on the reverse deformation vector domain data, perform reverse deformation on the original product upper model surface to obtain the upper model surface after reverse deformation compensation.

[0010] Step S4: Perform formability analysis on the upper model surface of the original product in CAE analysis software to obtain the thinning vector domain data of each position after the part is formed.

[0011] Step S5: Using the upper model surface after reverse deformation compensation as a reference, and based on the thinning vector domain data and the part thickness, the lower model surface of the original product is offset with unequal gaps to obtain the lower model surface after reverse compensation.

[0012] Preferably, in step S3, the reverse deformation vector domain data is multiplied by the deformation coefficient, and then the original product upper model surface is subjected to reverse deformation to obtain the upper model surface after reverse deformation compensation.

[0013] Preferably, the deformation coefficient ranges from 0.8 to 1.2.

[0014] Preferably, after obtaining the upper model surface after reverse deformation compensation, the machine tool table and mold structure are subjected to load deformation CAE analysis again to verify whether the upper model surface after reverse deformation compensation meets the requirements.

[0015] Preferably, after the deformation coefficient is determined, the surface deformation function of the drafting software is used to fit and reconstruct the upper model surface of the original product to obtain the upper model surface after reverse deformation compensation.

[0016] Preferably, the drafting software is CAD.

[0017] Preferably, the finite element analysis software in step S1 is Ansys.

[0018] Preferably, the CAE analysis software in step S4 is Autoform.

[0019] The beneficial effects of this invention are as follows:

[0020] The mold surface pretreatment method of the present invention considers the elastic deformation of the machine tool table and mold body during loading when processing the upper mold surface of the original product, and obtains the upper mold surface after reverse deformation compensation based on this. When processing the lower mold surface of the original product, the thinning during the part forming process is considered, and the lower mold surface of the original product is offset with unequal gaps based on the upper mold surface after reverse deformation compensation, thereby obtaining the lower mold surface after reverse compensation. This ensures that the processed mold surface can fit well with the part, effectively improves the fitting rate of the mold surface, and reduces the workload of fitter when adjusting the mold surface, reduces the occurrence of part forming problems such as springback waves, bulges, and depressions, and improves the quality of the part. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly described below, and the specific embodiments of the present invention will be further described in detail with reference to the drawings, wherein...

[0022] Figure 1 A flowchart of a mold surface preprocessing method provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the upper surface of the original mold after loading deformation, provided in an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the upper model surface after reverse deformation compensation provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram showing the original upper and lower model surfaces when closed, as provided in an embodiment of the present invention.

[0026] Figure 5 for Figure 4 Enlarged view of point A in the middle;

[0027] Figure 6 This is a schematic diagram of the thinning at various locations of the formed part provided in an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram showing the closed state of the upper and lower model surfaces after processing, as provided in an embodiment of the present invention.

[0029] Figure 8 for Figure 7 Enlarged view of point B in the middle.

[0030] Marked in the attached diagram:

[0031] 100. Upper mold; 101. Upper mold surface of the original product; 102. Deformation position of the upper mold surface.

[0032] 103. The upper model surface after reverse deformation compensation;

[0033] 200. Lower mold; 201. Original product lower mold surface; 202. Lower mold surface after reverse compensation. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the present solution will be further described in detail below with reference to specific embodiments.

[0035] like Figure 1 As shown, this embodiment of the invention provides a mold surface pretreatment method, which includes the following steps:

[0036] Step S1: Design a 3D mold structure based on the mold surface of the original product, and mesh and model the mold structure together with the production machine tool table in the finite element analysis software.

[0037] Step S2: Perform loading deformation CAE analysis and output the deformation vector domain data of the model surface of the original product;

[0038] Step S3: Generate reverse deformation vector domain data based on the deformation vector domain data. Based on the reverse deformation vector domain data, perform reverse deformation on the original product upper model surface to obtain the upper model surface after reverse deformation compensation.

[0039] Step S4: Perform formability analysis on the upper model surface of the original product in CAE analysis software to obtain the thinning vector domain data of each position after the part is formed.

[0040] Step S5: Using the upper model surface after reverse deformation compensation as a reference, and based on the thinning vector domain data and the part thickness, the lower model surface of the original product is offset with unequal gaps to obtain the lower model surface after reverse compensation.

[0041] The mold surface preprocessing method provided in this invention considers the elastic deformation of the machine tool table and mold body during loading when processing the upper mold surface of the original product, and obtains the upper mold surface after reverse deformation compensation based on this. When processing the lower mold surface of the original product, the thinning during the part forming process is considered, and the lower mold surface of the original product is offset with unequal gaps based on the upper mold surface after reverse deformation compensation, thereby obtaining the lower mold surface after reverse compensation. This ensures that the processed mold surface can fit well with the part, effectively improves the fitting rate of the mold surface, and reduces the workload of fitter when adjusting the mold surface, reduces the occurrence of part forming problems such as springback waves, bulges, and depressions, and improves the quality of the part.

[0042] Further, in step S3, the reverse deformation vector domain data is multiplied by the deformation coefficient, and then the original product upper model surface is subjected to reverse deformation to obtain the upper model surface after reverse deformation compensation.

[0043] Specifically, the value of the deformation coefficient ranges from 0.8 to 1.2.

[0044] Furthermore, after obtaining the upper model surface after reverse deformation compensation, a CAE analysis of the loading deformation is performed again on the machine tool table and mold structure to verify whether the upper model surface after reverse deformation compensation meets the requirements. During verification, if the upper model surface after loading and reverse deformation compensation does not meet the requirements, such as the deformation of the upper model surface being insufficient to compensate for the deformation of the original product's upper model surface or exceeding the deformation of the original product's upper model surface, the deformation coefficient is modified until the obtained upper model surface after reverse deformation compensation meets the requirements.

[0045] Specifically, after the deformation coefficient is determined, the surface deformation function of the drafting software is used to fit and reconstruct the upper model surface of the original product to obtain the upper model surface after reverse deformation compensation.

[0046] Ideally, the drafting software should be CAD.

[0047] Preferably, the finite element analysis software in step S1 is Ansys.

[0048] Autoform is a preferred CAE analysis software in step S4. It is understood that the original product is the original mold.

[0049] like Figure 2 and Figure 3 As shown, in one embodiment provided by the present invention, the processing procedure for the model surface of the original product is as follows:

[0050] First, a 3D mold structure is designed based on the original product mold surface. The mold structure, together with the production machine tool table, is meshed and modeled in finite element analysis software such as Ansys. Then, loading is performed, and elastic deformation analysis is conducted using CAE.

[0051] CAE analysis is used to analyze the deformation position 102 of the upper model surface 101 after loading and deformation of the original product, and the deformation vector domain data is output. Based on the deformation vector domain data, reverse deformation vector domain data is generated.

[0052] After multiplying the reverse deformation vector domain data by a deformation coefficient, the original product's upper model surface is fitted and reconstructed in CAD software using the surface deformation function to obtain the upper model surface 103 after reverse deformation compensation. Specifically, this can be expressed as: reverse compensation amount x = -y × α, where -y is the reverse deformation amount, and α is the deformation coefficient, with a value ranging from 0.8 to 1.2. In the specific embodiment shown in Figure 2, the maximum local deformation of the original product's upper model surface 101 after machine tool loading is +0.42 mm. Calculating the deformation coefficient as 1.0, the maximum compensation amount of the upper model surface 103 after reverse deformation compensation is -0.42 mm. It is understandable that... Figure 2 In this context, F represents the applied force.

[0053] like Figures 4 to 8 As shown, taking a part with a material thickness of 0.7mm as an example, the design gap between the upper and lower die surfaces of a conventional stamping die is 0.7mm. The processing procedure for the lower die surface 201 of the original product is as follows:

[0054] First, the formability analysis of the original product's upper model surface 101 is performed using CAE analysis software such as Autoform to obtain the thinning data of various locations on the formed part. For ease of understanding, as follows: Figure 6As shown in the enlarged partial schematic diagram after the part is formed, the thinning data at three locations after the part is formed are as follows: thinning at position 301a -0.135mm, thinning at position 301b -0.048mm, and thinning at position 301c -0.119mm.

[0055] Then, in the CAD software, based on the aforementioned thinning data and material thickness, and using the upper model surface 103 after reverse deformation compensation as a reference, the lower model surface of the original product is offset with unequal gaps to obtain the lower model surface 202 after reverse compensation. Figure 8 In the specific embodiment shown, with Figure 6 The gaps between the lower and upper model surfaces after processing, corresponding to the three thinning data points, are as follows: the gap at position 202a is 0.7mm-0.135mm=0.565mm, the gap at position 202b is 0.7mm-0.048mm=0.652mm, and the gap at position 202c is 0.7mm-0.119mm=0.581mm.

[0056] This invention is well applicable to the manufacturing and processing of forming molds for parts of different shapes made of metal sheets such as steel and aluminum. When processing the upper and lower surfaces of the mold, it not only considers the loading elastic deformation of the machine tool and mold fixture, i.e., the deformation vector domain data obtained by modeling the machine tool table and mold body structure in CAE software and performing structural deformation theory analysis, but also considers the thinning during the part forming process, i.e., obtaining the part thinning data through CAE simulation analysis of part formability. It can cover the entire surface, so that the gap between the upper and lower model surfaces after processing is consistent with the thickness of the formed part, thereby achieving a high fitting rate of the mold surface and high fitting accuracy between the mold and the part during the mold production process, thus improving the quality of the part.

[0057] The above are merely preferred embodiments of the present invention. It should be noted that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Moreover, after reading the contents of the present invention, those skilled in the art can make various modifications or alterations to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for pre-processing mold surfaces, characterized in that, It includes the following steps: Step S1: Design a 3D mold structure based on the mold surface of the original product, and mesh and model the mold structure together with the production machine tool table in the finite element analysis software. Step S2: Perform loading deformation CAE analysis and output the deformation vector domain data of the model surface of the original product; Step S3: Generate reverse deformation vector domain data based on the deformation vector domain data. Based on the reverse deformation vector domain data, perform reverse deformation on the original product upper model surface to obtain the upper model surface after reverse deformation compensation. Step S4: Perform formability analysis on the upper model surface of the original product in CAE analysis software to obtain the thinning vector domain data of each position after the part is formed. Step S5: Using the upper model surface after reverse deformation compensation as a reference, based on the thinning vector domain data and the part thickness, the lower model surface of the original product is offset with unequal gaps to obtain the lower model surface after reverse compensation. In step S3, the reverse deformation vector domain data is multiplied by the deformation coefficient, and then the original product upper model surface is subjected to reverse deformation to obtain the upper model surface after reverse deformation compensation. After the deformation coefficient is determined, the surface deformation function of the drafting software is used to fit and reconstruct the upper model surface of the original product to obtain the upper model surface after reverse deformation compensation.

2. The mold surface pretreatment method according to claim 1, characterized in that, The value of this deformation coefficient ranges from 0.8 to 1.

2.

3. The mold surface pretreatment method according to claim 1, characterized in that, After obtaining the upper model surface after reverse deformation compensation, the machine tool table and mold structure are subjected to load deformation CAE analysis again to verify whether the upper model surface after reverse deformation compensation meets the requirements.

4. The mold surface pretreatment method according to claim 1, characterized in that, The drafting software is CAD.

5. The mold surface pretreatment method according to claim 1, characterized in that, The finite element analysis software used in step S1 is Ansys.

6. The mold surface pretreatment method according to claim 1, characterized in that, The CAE analysis software used in step S4 is Autoform.

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