JPS61111731A - Overcrown forming method of punch - Google Patents

Abstract

PURPOSE:To make it unnecessary to correct repeatedly the shape of a punch, and to shorten a die correcting period by grasping in advance the position and quantity of an overcrown required for eliminating distortion in case of drawing, by painted film applied to a material. CONSTITUTION:A material is placed on a lower blank holder 8 of a press so as to become a state that it has been pinched by an upper blank holder 11. also, press working is suspended in front of the bottom dead center of a state that a punch part 6 has contacted to the material. Subsequently, a prepared partially fabricated item material 1a is fetched, and an applied film 12 is formed by spraying repeatedly a paint to the material 1a. Next, the material on which the applied film 12 has been formed is inserted into a press die again, the punch part 6 is made to descend to the bottom dead center, and a product is made. In this case, if the applied film 12 is thin, distortion is generated, and if it is thick, the applied film 12 is crushed, and no distortion is generated. Also, if the thickness of the applied film 12 is optimum, the punch part 6 abuts only. Accordingly, a press metallic die is manufactured by driving a radius of curvature by measuring the thickness of an optimum applied film of a slightly crushed film, and interweaving the position and quantity of an overcrown into the punch part 6.

Description

[Detailed description of the invention] (Industrial application field) In order to remove the distortion that occurs during press drawing,
The present invention relates to a method for forming a punch overcrown in which a punch is manufactured by determining the position and position at which the shape of the punch in a press mold is changed (overcrown) from the normal shape.

(Prior art) Conventionally, the position and width of the overcrown were predicted based on the design drawings and the experience and intuition of the mold maker and incorporated into the punch shape.

Furthermore, when distortion occurs during drawing of the material, the shape of the overcrown lid is estimated from the IW and size of the distortion, the shape of the punch is changed, and a new punch is manufactured.

(Problem to be solved by the invention) Therefore, with the above drawing dies, the stitching and position of the overcrown are not accurate, and when actually drawing the material, it is difficult to find the optimal one based on the result. In order to produce a punch with an over-crown lid, we went through a lot of trial and error, changing the shape of the punch, going through multiple trials, and making many different types of prototypes. It had become.

In order to solve the above-mentioned problems, the present invention eliminates the need to repeatedly modify the shape of the punch by accurately understanding the position and amount of overcrown required to remove distortion in advance using a prototype. The purpose is to shorten the correction period for molds.

(Means for Solving the Problems) In order to achieve all of the above objects, the present invention provides a seventh method in which a material is put into a press die, the material is sandwiched and held by upper and lower blank holders, and then the punch part Stop before the bottom dead center, take out the material, or apply IB to the part where distortion occurs on the spot to form a film of paint, and then press the material again to prevent distortion from occurring. Optimum paint film thickness 'f: Measure, determine the position and amount of the overcrown that is safe to eliminate this clumping and distortion, and by fitting it into the shape of the punch part, create a punch shape that does not cause distortion. It is characterized by making.

(Function) Next, the present invention will be explained in detail. First, the product material is inserted into the press drawing φ mold, the material is held down by the upper and lower blank holders, and the punch part is temporarily stopped at the bottom dead center 6 right. In this state, no distortion occurs in the material, so paint is then applied to the areas where distortion occurs. Depending on the position and amount of the coating film of this paint,
Oats (- This will determine the amount of crown to be inserted into the punch section.)

In other words, when a semi-finished product material coated with a powder coating is pressed again, the material sandwiched between the punch and die is pressed strongly by the built-up coating film in the area where distortion occurs.
Distortion will no longer occur.

In this way, a similar product can be made if the punch is pressed with a pre-crowned oat.

Therefore, if the key of the coating film at this time is measured and an overcrown is built into the punch part of the main type, there will be no need to modify the prototype punch every time.

(Example) The overcrown building method of the present invention will be explained based on the drawings.

Fig. 1 shows a press-worked door part l of a vehicle shown as an example. The material 1a to be press-worked is a cold-rolled steel plate for deep drawing such as 5PC2, and has a flatness of about αγ■. A thin plate is used.

For this reason, if a press mold is manufactured based on the design drawing,
Due to the materials and processing, the hatched areas in 1 will be inspected near the parts where the product shape changes.

This distortion, as is clear from the plan view of part A in Figure 2,
A recessed portion B is formed because it does not match the shape of the die or punch of the mold. In order to eliminate the recessed portion B, the punch portion that comes into contact with the portion where distortion occurs is usually overcrowned.

In other words, the punch portion is provided with a radius of curvature of approximately 7000 mm or more.

The position and amount of this overcrown are accurately determined and incorporated into the punch of this type.

For this purpose, a double-acting press apparatus [2] having a prototype mold shown in FIGS. 5 and 6 assembled is used.

The press device 2 is divided into an upper movable part and a lower fixed part, and the upper fixed part is attached to the inner ram 3 via an adapter plate 4 to punch the shape of the product onto the punch riser 5. A punch portion 6 is assembled.

On the other hand, the lower fixed part has a die part 7 that matches the shape of the punch part 6, and the outer edge of the die part 7 forms a lower blank holder 8.

Further, an outer ram 9 is provided on the outside of the inner ram 3 and moves up and down in response to the up and down movement of the ram 3.Atsuno (-blank holder 11) is attached to this ram 9 via a blank holder brake (10). It is being

Place the workpiece 1& on the lower blank holder 8 of this press device 1120 and make it sandwiched between the blank holders 11.Furthermore, the punch part 6 is in contact with the workpiece 11, that is, before the bottom dead center. Pressing is stopped.The semi-finished products 1a thus produced are taken out, the shape of the product is estimated, and a coating film 12 is formed by repeatedly spraying paint onto each material 1a as shown in FIG. The coating film 12 is prepared in various lengths, for example, from 0.1 m to 0.5 m.

Next, each material 1a on which the coating film 12 has been formed is inserted into a press mold, and as shown in FIG. 6, the punch section 6 is lowered to the bottom dead center to form a product.

In this case, if the sprayed coating film 12 is thin, distortion will still occur, and if the coating film 12 is thick, it will be crushed by the punch portion 6 and the material 1aK, and no distortion will occur. Furthermore, if the thickness of the coating film 12 is optimal, the punch portion 6 will only come into contact with the coating film 12.

In this way, the optimum coating film 111 without distortion or the coating film 111 in a slightly crushed state is measured with the indicator 13 such as a dial gauge, the radius of curvature is determined, and the overcrown position is directly adjusted. and salmon are woven into the punch part 6 to produce a press mold.

In this example, the punch 6 is applied to the blank 1a as a press-processed material, the processing is temporarily stopped before the bottom dead center of the punch 6, and after the shape of the product is visible, the paint is applied. It's spraying.

This is to prevent the coating film sprayed on the material from peeling off due to plastic deformation of the material 1a during the drawing process, that is, elongation, compression, or wrinkles of the material, and to roughly confirm the areas where distortion occurs. This is to do so. Therefore, if the above-mentioned problems do not occur, it is possible to omit the pressing step before applying the paint as a simple method.

Alternatively, the thickness of the coated film may be measured not after the final press working, but before the final press working, by preparing materials on which coated films of several different thicknesses have been formed and pressing them one after another.

In this case, look at the product after pressing, select a coating film that is said to be suitable for Tik from among those that do not cause distortion, and measure the amount of overcrown to be woven into the punch part from the coating film 1] which has been measured in advance. Determine and manufacture the optimal punch.

(Effects of the Invention) As is clear from the above explanation, conventionally, in order to eliminate the occurrence of distortion in drawn products, the shape of the punch was repeatedly corrected in the prototype mold, and the optimal main mold was found. However, according to the present invention, the position and amount of overcrown required for the punch part of the main die are replaced with a coating film applied to the material, and the actual pressing process is performed to eliminate the occurrence of distortion. Make sure you don't.

In this way, processed NFC#! Based on the measured values of the coating film, which ranged from the product to the optimum, the shape of the first prototype punch was determined.
The amount and location of the missing overcrown can be determined.

Therefore, without changing or modifying the punch, it is possible to determine the shape of the punch required for the actual mold using -1 trial molds, and the mold correction period can be shortened.

This has the effect of shortening the production preparation period and speeding up product launch.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a pressed product according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line X-X of the strain generating portion A shown in Fig. 1, and Fig. 3 is a material of the embodiment. Figure 4 is a cross-sectional view showing the state in which the paint is sprayed and the next state is applied. Figure 4 is a cross-sectional view showing the state in which the film thickness of the paint is measured when the strain has been removed. Figure 5 is a cross-sectional view showing the state in which the paint film thickness is measured after the strain has been removed. Figure 5 is the processing of the material before the bottom dead center. FIG. 6 is a cross-sectional view of the press device when the material on which the coating film has been formed is pressed. 1a...Material 2...Press device 6...Punch part 8...Lower blank holder 11...Upper blank holder 12...Coating film

Claims (1)

[Claims] (1) After putting the material into the press mold and holding the material between the upper and lower blank holders, the punch section is stopped before the bottom dead center and the material is taken out, or the material is distorted on the spot. Apply paint to the area to form a paint film, press this material again, find the optimal paint film thickness that does not cause distortion, and calculate the necessary amount to remove distortion from the measured film thickness. A punch overcrown forming method characterized by determining the position and amount of the overcrown and weaving it into the shape of the punch portion to create a punch portion that does not cause distortion.