Computer aided design of the hottest cold stamping

Computer aided design of cold stamping and drawing die

when designing the cold stamping and drawing die, it is necessary to have a clear understanding of the brand of the stamping part material, the selected press model, the drawing force of the stamping part, and clarify the die structure and the processing method of the subsequent die. The die design module in NX software provides the common functions of mold design, and its general process for cold stamping and drawing mold design is as follows:

1. Import or construct the three-dimensional CAD model of the product/sample

import the CAD model after the Construction Evaluation in the stamping die design engineering into the software, or use the die design module under NX software system to design and construct the three-dimensional model of the product according to the requirements of customers or the ideas of designers

2. Process inspection of 3D CAD die surface

process analysis of 3D CAD die surface includes two aspects: product process supplement integrity and continuity; Whether there is a negative angle in the process supplement

3. Create a drawing punch

generally, there is one drawing and multiple drawing. In most cases, only one drawing is done, and the integral punch and die are made. The drawing punch is the working part of the die. The design of the drawing punch should be based on the CAD digital die surface

4. Create the upper die body

first, determine the overall dimensions of the upper die body according to the distance between the two upper die base plates and the general dimensions of the punch in the length and width directions, then make U-shaped grooves and stiffeners for fixing, and finally create relief holes, keyways and other details

5. Create drawing die

the design of drawing die should be based on the CAD model surface made previously

6. create blank holder ring

blank holder ring plays a decisive role in sheet metal flow and determines the forming quality. Therefore, the design of blank holder ring determines the quality of die in a certain sense

7. Assembly

assembly is divided into complete assembly and incomplete assembly. Here is incomplete assembly, that is, process digital simulation, punch, die, blank holder and press backing plate are assembled under t-document as separate parts. The assembled state is that the mold is completely closed

fender die design - double acting drawing die design

1. import the reference model

start the NX system, select file new under file (menu), click the left button, enter the file name under file new name: Yi Zi T, and click OK to enter the die design interface. Select import - Part - t from the file drop-down menu, and the digital analog import is completed (see Figure 1)

Figure 1 import the reference model

2. Digital simulation

place the product digital simulation, process supplement surface and process supplement line in layers respectively. Check the digital simulation of the product and the supplementary surface of the process (mainly check the heavy surface, missing surface, gap and sharp corner, etc.), repair the problems found, and sew the piece after the repair. Specific operations: use the commands of n-sided surface, trimmed sheet, sweep and bridge to repair the sheet respectively, as shown in Figure 2. Under the insert drop-down menu, select combine bodies - sew, and select pieces to sew

Figure 2 physical examination and repair

3. Create drawing punch

(1) create drawing entity of parting line. Of parting line: use the join curves command to connect the parting line. Use the projection command to project the rear parting line to the z plane. Use the edit curve command to edit the curve projected on the z plane. Solid generation: select design feature - extrude from the insert drop-down menu, and extrude the selected curve, as shown in Figure 3

Figure 3 formation of stretched body

(2) entity segmentation. Under the insert drop-down menu, select trim - split body, select the stretched body, split the solid with the sewn sheet, and delete the lower half of the split solid to obtain the punch solid (see Figure 4)

Figure 4 punch entity generation

(3) the specific steps of punch production are as follows:

① make the parting surface withdrawal tool. Under the insert drop-down menu, select associative copy - extract geometry, select the parting surface, and click OK to hide the punch body, leaving only the pieces left by the parting surface extraction. Under the insert drop-down menu, select offset/scale - thicken, and select the sheet to confirm. The offset thickness is -10mm and 10mm. Move the offset entity forward by 50mm along the Z axis, and then carry out the subtract operation with the punch entity, and the tool withdrawal of the parting surface is completed

② make the installation surface of guide slide plate and safety stop. According to the drop of the parts, the length of the guide plate is determined to be 200mm. According to the design standard (the width of the guide plate is generally 20% - 25% of the length of the parting line), the installation surface of the guide plate is designed to be 150mm × 200mm, a total of 12 places are designed all around; The specification of safety stop is 95mm (length) × 55mm (width) × 65mm (height); Use the commands such as block, unite and subtract to make the installation surface of the guide plate and the safety stop respectively

③ create stiffeners and local stiffeners. Use the block (box) and offset face commands to make a drawbead. Select transformation - translate from the edit pull-down menu, and use the move and copy commands to select the finished drawbead and move and copy it according to the design standard. Find the position of CH hole and exhaust hole, and avoid the drawbead (see Figure 5)

Figure 5 stiffeners and local stiffeners

④ make the U-shaped groove of the fixed punch. Select part fami in turn under the tools menu, so we need to master the correct online method to prevent this kind of situation. Lies - browse - go to the standard parts library, select the U-shaped slot, do it as needed, click OK to remove parameters, and then copy the U-shaped slot to Yi Zi T, and then move it Unite (and) and subtract (subtract) and other commands will make the U-shaped groove of the fixed punch

⑤ install self-lubricating guide plate and overturning lifting lug. Using the calling method of punch U-groove, the self-lubricating guide plate and overturning lifting lug are introduced in turn, and they are installed in place by using the commands of move and copy

(4) the specific steps of making the upper mold body are as follows:

① determine the general size of the upper mold body. According to the distance between the two upper base plates and the general dimensions of the punch in the length and width directions, the overall dimension of the upper die body is determined to be 2100mm × 960mm × 290mm, use the block (box) command to make the solid

② refine the upper mold body. The upper and lower U-shaped grooves are made by making U-shaped grooves of punch, and the bolt type lifting lugs are made by this method; The design method of punch stiffener is used to make the upper die stiffener; Select design feature - slot under the insert drop-down menu to design the keyway; Use block (box), unite (Union), subtract (subtract), edge blend (edge fillet), positioning keyway, lightening and other details respectively; Use the punch standard parts to call the installation method, install the upper die body standard parts, and firmly connect them with the punch (see Figure 6)

Figure 6 installation of punch standard parts and assembly of upper die body

(5) the specific steps of making concave die are as follows:

① design of pressure regulating block mounting platform and positioning plate mounting surface. Under the insert drop-down menu, select design feature - extrude, select the blank line, and extrude the body; Under insert, the company's focus at k2016 exhibition is to select trim - split body under the pull-up menu of 1 integrated manufacturing system, select stretching body, split the entity with sewn pieces, hide the upper half of the split entity, and get the die entity; Use the offset face command to offset the extruded solid by 20mm around; Use the extract geometry and thicken commands to generate six small entities around the entity, and select the small entity to move 30mm along the negative Z axis. Use the cylinder command to generate a cylinder with a diameter of 60mm and a height of 30mm; After parameter elimination, it is evenly arranged along the outside of the blank line, and the mounting surface of the positioning plate is arranged along the blank line (see Figure 7)

Figure 7 pressure regulating block mounting platform and locating plate mounting surface

② guide sliding leg design. Considering the feeding height and the strength of the guide leg, the design specification of the guide leg is 1680mm (length) × 650mm (width) × 340mm (high), the specification of guide plate mounting surface is 150mm (long) × 150mm (width), made with block (box), unite (Union) and subtract (subtract) commands respectively; Use the unite command to connect the sliding guide leg and the female die together, and use the cylinder and subtract commands to make the cylinder top feed through hole and CH hole, and mark the installation hole at the bottom

③ design of U-shaped groove and side bar. Use the method of making the U-shaped groove of the punch to make the U-shaped groove, and use this method to make the bolt type lifting lug, and use the commands of block (cuboid), chamfer (chamfer) to make the side bar

④ detailed design. Use the commands of block, unite, subtract and edge blend to design the details of roller positioning table, positive marking and reduction respectively. Use the method of calling and installing punch standard parts to install female standard parts

(6) the specific steps of making blank holder are as follows:

① the production of punch clearance hole, inner guide sliding surface and upper pier dead platform. Use the extrude command to select the parting line passed when making the punch and stretch it into a body. Then use the offset face command to offset the stretched entity by 3mm around. After the body is formed, call out the entity hidden during the making of the die, and use the subtract command to make a difference between the two entities; Use cylinder, block, unite, subtract, etc. my product only needs 5kg tension to make the installation surface of guide slide plate, pier dead circle and positioning plate clearance hole

② guide sliding leg design. The design of this part should be combined with the design of the guide sliding leg of the female die. The design specification of the guide leg is 1680mm (length) based on the consideration of the feeding height and the strength of the guide leg × 650mm (width) × 590mm (high), the specification of sliding guide surface is 150mm (long) × 150mm wide. Use block (box), unite (Union), subtract (subtract) and other commands to make them respectively

③ design of U-shaped groove and side bar. Use the method of making the U-shaped groove of the punch to make the U-shaped groove, and use this method to make the bolt type lifting lug. The core advantage of using block (cuboid), chamfer this model is that the body adopts commands such as carbon fiber composite material (chamfer) to make the side ribs. After making, use unite (and) command to connect the sliding guide leg, U-shaped groove, side ribs and blank holder body together

④ detailed design. Use the commands of block, unite, subtract, hole and edge blend to design the details of datum hole, positive marking, mitigation, avoidance and peephole respectively; Use the punch standard parts to call the installation method to install the blank holder standard parts

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