Method for shortening development cycle of inner and outer plate molds of left and right front vehicle doors

Abstract

The invention provides a method for shortening the development cycle of a mold for inner and outer plates of a left front vehicle door and a right front vehicle door. The method comprises the following steps of S1, OP30 flanging design, OP20 trimming and punching design, OP10 process drawing design and parting line determination, or OP40 punching and side punching separation design, OP30 flanging design, OP20 trimming and punching design and parting line determination; S2, OP10 process drawing design is conducted; s3, a CAE analysis forming test is conducted on the workpiece, and if the requirement is met, structural design is started; and if not, returning to the step S2. The method has the beneficial effects that the mold design period is shortened, 21 days are saved, the efficiency is improved by 35.6%, and it is guaranteed that the ultra-short project period can be smoothly achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of mold manufacturing, and in particular relates to a method for shortening the development cycle of molds for inner and outer panels of left and right front vehicle doors. Background Art

[0002] With the rapid development of the automotive industry, multi-dimensional competition is becoming increasingly fierce. In order to seize market share, the production cycle of large automotive cover molds has been continuously compressed, from 24 months before 2005 to 10 months in 2020. In 2023, customers have already required 6.5 months to complete mold shipment. This has raised new issues for mold manufacturers. How to meet customer requirements under the premise of higher quality requirements in such a short time and improve competitiveness in the industry has become a key issue for mold manufacturers. The design of automotive cover molds is divided into process design and structural design. Process design is the basis of structural design. The basis of process design must be provided before structural design can begin. Structural design is the final product. The issuance of the full-process mold structure design drawings marks the completion of the design stage and is an important node in mold development. Invention content

[0003] In view of this, the present invention aims to propose a method for shortening the development cycle of left and right front door inner and outer panel molds to solve at least one technical problem in the background technology.

[0004] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0005] 8. The method for shortening the mold development cycle of the left and right front door inner and outer panels includes the following steps:

[0006] Step S1: OP30 flanging design, OP20 trimming punching design, OP10 process drawing design, determine the parting line, or OP40 punching side punching separation design, OP30 flanging design, OP20 trimming punching design, determine the parting line,

[0007] S2: Carry out OP10 process drawing design;

[0008] S3: Perform CAE analysis and molding test on the workpiece. If the requirements are met, start structural design; if not, return to step S2.

[0009] Furthermore, in step S1, the OP40 punching side punching separation design includes the punching direction being the Y direction of the vehicle body; determining the minimum docking distance between parts, extracting the punching hole diameter and angle of the product positive punching side; confirming the angle direction of the door lock side flip hole; and confirming the separation range.

[0010] Furthermore, the minimum butt distance between the parts is 20-60 mm.

[0011] Furthermore, if there is no OP40 punching side punching separation design, the OP30 flanging design includes extracting the product perimeter and the door handle flanging contour, and determining the minimum distance between the workpiece butt joint and the flanging contour line;

[0012] If there is a OP40 punching side punching separation design, the OP30 flanging design includes the stamping direction being the Y direction of the vehicle body; the minimum docking distance between parts is the same as the OP40 punching side punching separation design; extract the product flanging contour line; confirm the design of the shaping parting line within the shaping range.

[0013] Furthermore, if there is no OP40 punching side punching separation design, the OP20 trimming punching design includes confirming the punching direction according to the punching trimming angle, extending the product profile, and ensuring that the trimming line is unfolded on the extended surface; the docking distance is consistent with the OP30 flanging process;

[0014] If there is a separate punching design for the OP40 punching side, the OP20 trimming punching design includes the punching direction being the Y direction of the vehicle body; the minimum docking distance between parts is the same as OP40; confirming the boundary line around the product; extracting the punching line and expanding the flanging trimming line.

[0015] Furthermore, in step S1 , the punching angle in the punching direction of the OP30 flanging design and the OP20 trimming punching design is not greater than ±5 degrees, and the trimming angle is not greater than ±15 degrees.

[0016] Furthermore, in step S2, the OP10 drawing die works by providing a blank holding force through the air ejector pins of the press. The use of the press includes selecting the number of ejector pins, each ejector pin provides a pressure of 5 tons, the total number of ejector pins selected is greater than the CAE blank holding force of the workpiece, and the position of the ejector pins is selected close to the parting line. The ejector pins are selected to ensure that the force on the machine tool and the mold is evenly balanced, and the number of ejector pins in the four quadrants of the center of the machine tool is consistent.

[0017] The CAE analysis forming test is the formability inspection and rigidity inspection of the CAE analysis of the parts. The formability inspection includes the maximum failure of thinning and wrinkling; the CAE analysis rigidity inspection of the parts shows that the principal strain is greater than 3% and the thinning rate is greater than 4%; the surface quality inspection of the parts after CAE analysis forming is that the slip line impact line does not exceed the product fillet, and the secondary stress change does not exceed 50 in the 100mm area.

[0018] Compared with the prior art, the method for shortening the development cycle of left and right front door inner and outer panel molds created by the present invention has the following advantages:

[0019] The mold design cycle was shortened, saving 21 days and increasing efficiency by 35.6%, ensuring that the ultra-short project cycle could be successfully achieved.

[0020] This application adopts the method of reverse process design to prioritize the fixed processes and directly carry out structural design after confirming the key elements with the customer. For example, the OP40 flanging process of the door outer panel mentioned above. Similarly, the OP20 and OP30 trimming and punching contents can be roughly arranged, and the focus can be on the design of confirmed work contents, such as punching, trimming inserts, and upper and lower die seats of the pressing core. After the OP10 drawing process confirms the parting line, the drawing die structure design can begin. Process design and structural design go hand in hand. After the process sign-off is completed, the structural design has been completed by about 60% at this point in time, which ultimately reduces the overall design cycle of the entire part. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0022] Figure 1 A schematic diagram of the structure of the OP30 flanging process described in Example 1 of the present invention;

[0023] Figure 2 A schematic diagram of the OP20 trimming and punching method described in Example 1 of the present invention;

[0024] Figure 3 A schematic diagram of OP10 drawing as described in Example 1 of the present invention;

[0025] Figure 4 A schematic diagram of the OP40 process arrangement described in Example 2 of the present invention;

[0026] Figure 5 A schematic diagram of the OP30 process arrangement described in Example 2 of the present invention;

[0027] Figure 6 This is a schematic diagram of the preliminary process of the OP20 left and right front door inner panels described in Example 2 of the present invention;

[0028] Figure 7 This is a schematic diagram of the preliminary process of the OP10 left and right front door inner panels described in Example 2 of the present invention;

[0029] Figure 8 The original process design and development flow chart described in Comparative Example 1 of the present invention;

[0030] Fig. 9 This is a schematic diagram of the profile of the vehicle door outer panel drawing process described in Comparative Example 1 of the present invention;

[0031] Fig.10 It is a schematic diagram of the pressing surface of the drawing process profile of the vehicle door outer panel described in Comparative Example 1 of the present invention;

[0032] Fig.11 Schematic diagram of the door outer panels OP20 OP30 OP40 described in Comparative Example 1 of the present invention (a is OP20, b is OP30, and c is OP40);

[0033] Fig.12 The process design and structural design development cycle diagram described in Comparative Example 1 of the present invention;

[0034] Fig.13 This is the OP40 flanging process design diagram described in Example 1 of the present invention;

[0035] Fig.14 This is the design diagram of the OP20 punching process described in Example 1 of the present invention;

[0036] Fig.15 This is the design diagram of the OP30 punching process described in Example 1 of the present invention;

[0037] Fig.16 This is a drawing die ejector arrangement diagram of the OP10 drawing die described in Example 1 of the present invention;

[0038] Fig.17 This is a process design and structural design development cycle diagram described in Example 1 of the present invention. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0040] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0041] Example 1

[0042] The left and right front door outer panels of a certain project have 3 processes: OP10 drawing, OP20 trimming and punching, and OP30 flanging.

[0043] Prioritize the design of OP30 flanging process, extract the product circumference and the door handle flanging contour, determine the minimum distance between the part and the flanging contour line is 60mm, and then issue the structure to start structural design, see below Figure 1 ;

[0044] The OP20 process involves trimming and punching. The punching direction is determined according to the trimming angle of the punching hole, and the product profile is simply extended to ensure that the trimming line is spread on the extended surface. The waste knife position is arranged according to customer requirements. The docking distance is consistent with the OP30 flanging process. After the above problems are confirmed, the OP20 trimming and punching die structure design is carried out, see below. Figure 2 .

[0045] OP10 process design confirms the drawing parting line and then carries out structural design, see below Figure 3 This project was implemented according to the new process development method, with a total cycle of 37 days from the project start-up process design to the issuance of structural drawings.

[0046] Example 2

[0047] The left and right front door inner panels of a certain project have a total of 4 processes, OP10 drawing, OP20 trimming and punching, OP30 flanging and shaping, and OP40 punching and side punching separation.

[0048] First, the OP40 process layout is carried out: 1. The stamping direction is the Y direction of the vehicle body. 2. The minimum docking distance between the parts is 20mm to ensure the strength of the trimming insert. 3. Extract the punching hole diameter and angle of the product's positive punching side. 4. Confirm the angle direction of the door lock side flip hole, 5. Confirm the separation range. The structure can be issued to start the structural design, see below Figure 4 .

[0049] OP30 process layout: 1. Stamping direction is the Y direction of the car body. 2. The minimum butt distance between parts is the same as OP40. 3. Extract the contour line of the product flange. 4. Confirm the shaping range and design the shaping parting line. Send the structure to start the structural design, see below Figure 5 .

[0050] OP20 process layout: 1. The stamping direction is the Y direction of the vehicle body. 2. The minimum butt distance between parts is the same as OP40. 3. The boundary line around the product. 4. Extract the punching line. 5. Expand the flanging and trimming line. Send the structure to start the structural design, see below Figure 6 .

[0051] OP10 process design confirms the drawing parting line and then carries out structural design, see below Figure 7 .

[0052] This project was implemented according to a new process development method, with a total cycle of 38 days from project initiation, process design to issuance of structural drawings.

[0053] Table 1 below shows the current mold process and structural design development plan arrangement

[0054]

[0055] The front door outer panel parts of a certain car model require 4 processes of die stamping, namely OP10 drawing, OP20 trimming punching, OP30 trimming punching, and OP40 flanging. From the mold design progress in the above table, it can be seen that the mold process structure design and development takes about 2 months. According to this plan, the production plan is pushed forward, the actual mold is made for 15 days, the lost foam casting is 30 days, the mold is returned to the factory for processing for 45 days, the assembly and debugging are 30 days, and the measurement sample is provided for 15 days. The total working hours are currently 6.5 months. There is no time for mold rectification and part precision rectification. The rectification time is 10 days, and there is no time for mold acceptance and problem cancellation. Mold process design and mold structure design are both very delicate work, which requires sufficient time for design, review, proofreading, countersigning and other links. All links are indispensable. If the design cycle is over-pressed, the loss caused by design abnormalities may be irreparable.

[0056] The original process development and design process of the parts is as follows Figure 8 .

[0057] First, the automobile manufacturer provides the digital model of the product that needs to be designed and developed, referred to as the product digital model. This is the most basic basis for mold development. Mold development is the process of how to finally realize this product data through four mold processes.

[0058] S1 stage: The process designer of the mold manufacturer makes a supplementary design of the OP10 drawing process based on the product digital model. Figure 3 .The drawing process design is a complex process. First of all, it must meet the requirements of formability such as wrinkling and cracking of the parts. The thinning rate is less than 0.2% of the sheet thickness, the maximum failure rate is less than 0.7, and the wrinkling height is less than 0.03mm. (Additional implementation examples are required, which are suitable for implementation and which factors are mainly considered), and the requirements of part accuracy and appearance quality must be met. The main strain of the product area is greater than 3%, and the secondary strain is greater than 0.01%. Neither the slip line nor the impact line can exceed the fillet area of ​​the product. On the basis of meeting the above conditions, the material utilization rate is controlled to the maximum. These require repeated CAE analysis results verification and inspection in the S2 stage to finally meet the requirements of formability, dimensional accuracy and appearance quality.

[0059] When S2 meets the requirements, S3 carries out the design of OP20, OP30, and OP40 process contents, such as Fig.11 As shown. The process profiles of OP20 and OP30 are consistent with drawing, but the difference is that the process content of trimming is arranged according to the angle of punching and trimming. The process profile of OP40 is consistent with the product, and the stamping direction needs to be confirmed according to the direction of flanging, and the flanging surface is made according to the stamping direction. In order to maintain the assembly relationship of the door assembly on the body, the stamping direction of the door outer panel OP40 is usually designed according to the Y direction of the body.

[0060] The S4 stage is an internal review of the entire process. After the review is qualified, the process will be signed with the customer. The main contents of the sign-off include the formability inspection of the CAE analysis of the workpiece, including the maximum failure of thinning and wrinkling; the rigidity inspection of the CAE analysis of the workpiece shows that the principal strain is greater than 3%, and the thinning rate is greater than 4%; the surface quality inspection of the CAE analysis of the workpiece after forming, the slip line impact line does not exceed the product fillet, and the secondary stress change area of ​​100mm does not exceed 50. The material utilization rate of the workpiece cannot be further improved to reach the maximum value when the above conditions are met. If the thinning of the workpiece analysis is high, it is necessary to reduce the drawing depth or increase the supplementary draft angle to facilitate the forming of the workpiece. If the wrinkling of the workpiece analysis is serious, it is necessary to fully draw or increase the characteristic shape to convert the wrinkled material into a fixed feature. If the impact line and slip line exceed the product fillet, the stamping direction needs to be adjusted so that both sides of the edge position are in uniform contact with the sheet to avoid slippage. If the local secondary stress of the product changes sharply, it can be optimized by adding supplementary shapes. Finally, according to the customer's sign-off opinions, after the rectification is qualified, the supporting structure design process will be issued to start the structure design. The process design and structure design development cycle is shown below Fig.12 :

[0061] The existing technology has the problem that the mold design cycle is long and cannot be compressed while ensuring quality. The structural design needs to wait until the process is completed before it can start. The final completion is only after all the mold structure designs of a part are completed. The design with the longest cycle determines the overall cycle.

[0062] This patent invented a new design method to shorten the mold development cycle. A rule can be found by studying the process characteristics of the inner and outer door panels. First of all, the stamping direction of the OP40 flanging process of the door outer panel is usually the Y direction of the vehicle body to ensure that the flanging profile is consistent with the design direction of the vehicle body. Confirm whether the flanging angle meets the customer's requirements for the edge angle or rolling angle in the stamping direction. Check the edge angle in the Y direction of the vehicle body. If it meets the customer's requirements, ordinary positive flanging is used. If it cannot meet the customer's requirements, side flanging is used. The OP40 process profile is mainly based on the product digital model itself and has nothing to do with drawing supplementation.

[0063] The OP40 structural design can be carried out by confirming the OP40 process plan with the customer in advance. In the past, the process design and structural design were separated. The structural design was started only after all the process sign-offs were confirmed. Since the previous project cycle could meet the overall project requirements, the design was carried out step by step. If the product changes or the hemming and hemming changes in advance, the structural design may be scrapped and the production capacity needs to be wasted due to the need for redesign.

[0064] Secondly, the two processes of OP20 and OP30 punching and trimming are arranged according to conventional experience. The punching angle in the punching direction is preferably not greater than ±5 degrees, and the trimming angle is not greater than ±15 degrees. The trimming angle is less than -15 degrees, which is an acute trimming angle. The trimming insert is sharp and has poor strength. It is easy to crack during the stamping process, which affects the life of the trimming insert. The trimming angle is greater than +15 degrees, which increases the actual thickness of the cutting edge, making the cutting edge too stressed and easy to be damaged. At the same time, the horizontal force causes the trimming gap to change and produce burrs. . Keep the maximum diagonal length of the scrap size no more than 500mm. When arranging the trimming, you can draw a circle with a diameter of 1000mm with the starting point as the center. The scrap cannot exceed the required part of the drawing and supplementing surface. The trimming boundary and punching position are fixed.

[0065] Finally, the OP10 drawing process. The OP10 drawing die needs to be provided with a blank holding force by the air ejector of the press to work. The design of the OP10 drawing die is seriously affected by the arrangement of the ejector hole. The specific position of the machine tool ejector must be confirmed after the drawing process is supplemented and determined before the OP10 drawing die design can be carried out.

[0066] Drawing die ejector arrangement: 1. The number of ejector pins is selected. Each ejector pin provides a pressure of 5 tons. The total number of ejector pins selected is greater than the CAE blank holding force of the workpiece. 2. The ejector pin position is selected close to the parting line. 3. The ejector pin selection ensures that the machine tool and the die are evenly balanced, and the number of ejector pins in the four quadrants of the machine tool center is consistent.

[0067] The CAE analysis forming test is the formability inspection and rigidity inspection of the CAE analysis of the parts. The formability inspection includes the maximum failure of thinning and wrinkling; the rigidity inspection of the CAE analysis of the parts is greater than 3%, and the thinning rate is greater than 4%; the surface quality inspection of the CAE analysis of the parts after forming, the impact line of the slip line does not exceed the product fillet, and the secondary stress change does not exceed 50 in the 100mm area. If the requirements are met, the structural design will begin; if not qualified, return to the OP10 drawing process.

[0068] In summary, this application adopts the method of reverse process design to prioritize the processes with fixed procedures and directly carry out structural design after confirming the key elements with the customer. For example, the above-mentioned OP40 flanging process of the door outer panel. Similarly, the OP20 and OP30 trimming and punching contents can be roughly arranged, and the focus can be on the design of confirmed work contents, such as punching, trimming inserts, and upper and lower die seats of the pressing core. After the OP10 drawing process confirms the parting line, the drawing die structure design can begin. Process design and structural design go hand in hand. After the process sign-off is completed, the structural design has been completed by about 60% at this point in time, which ultimately reduces the overall design cycle of the entire part.

[0069] like Fig.17As shown in the figure, the overall design cycle is more optimized by adopting the new process design method. The overall design cycle of the mold is reduced from 59 days to 38 days, saving 21 days and increasing the efficiency by 35.6%, which buys precious time for the later mold debugging and rectification.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for shortening the mold development cycle for the left and right front door inner and outer panels, characterized by: The steps include: Step S1: OP30 flanging design, OP20 trimming punching design, OP10 process drawing design, determine the parting line, or OP40 punching side punching separation design, OP30 flanging design, OP20 trimming punching design, determine the parting line, S2: Carry out OP10 process drawing design; S3: Perform CAE analysis and molding test on the workpiece. If the requirements are met, start structural design; if not, return to step S2.

2. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 1, characterized in that: The OP40 punching side punching separation design in step S1 includes the punching direction being the Y direction of the vehicle body; determining the minimum docking distance between parts, extracting the punching hole diameter and angle of the product positive punching side; confirming the angle direction of the door lock side flip hole; and confirming the separation range; The stamping direction of the OP40 flanging process of the door outer panel is usually the Y direction of the body to ensure that the flanging profile is consistent with the design direction of the body; confirm whether the flanging angle meets the requirements of the edge angle or the rolling angle in the stamping direction.

3. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 2, characterized in that: The minimum butt distance between parts is 20-60mm.

4. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 1, characterized in that: If there is no OP40 punching side punching separation design, the OP30 flanging design includes extracting the product circumference and the door handle flanging contour, and determining the minimum distance between the part joint and the flanging contour line; If there is a OP40 punching side punching separation design, the OP30 flanging design includes the stamping direction being the Y direction of the vehicle body; the minimum docking distance between parts is the same as the OP40 punching side punching separation design; extract the product flanging contour line; confirm the design of the shaping parting line within the shaping range.

5. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 1, characterized in that: If there is no OP40 punching side punching separation design, the OP20 trimming punching design includes confirming the punching direction according to the punching trimming angle, extending the product profile, and ensuring that the trimming line is unfolded on the extended surface; the docking distance is consistent with the OP30 flanging process; If there is a separate punching design for the OP40 punching side, the OP20 trimming punching design includes the punching direction being the Y direction of the vehicle body; the minimum docking distance between parts is the same as OP40; confirming the boundary line around the product; extracting the punching line and expanding the flanging trimming line.

6. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 1, characterized in that: In step S1, the punching angle in the punching direction of the OP30 flanging design and the OP20 trimming punching design is not greater than ±5 degrees, and the trimming angle is not greater than ±15 degrees.

7. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 1, characterized in that: In step S2, the OP10 drawing die works by providing a blank holding force through the air ejector pins of the press. The use of the press includes selecting the number of ejector pins. Each ejector pin provides a pressure of 5 tons. The total number selected is greater than the CAE blank holding force of the workpiece, and the position of the ejector pin is selected close to the parting line. The ejector pin selection ensures that the force on the machine tool and the mold is evenly balanced, and the number of ejector pins in the four quadrants of the machine tool center is consistent.

8. The method for shortening the mold development cycle of left and right front door inner and outer panels according to claim 1, characterized in that: The CAE analysis forming test is the formability inspection and rigidity inspection of the CAE analysis of the parts. The formability inspection includes the maximum failure of thinning and wrinkling; the CAE analysis rigidity inspection of the parts shows that the principal strain is greater than 3% and the thinning rate is greater than 4%; the surface quality inspection of the parts after CAE analysis forming is that the slip line impact line does not exceed the product fillet, and the secondary stress change does not exceed 50 in the 100mm area.

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