KR101403668B1 - Press mold manufacturing method for production of hot stamping cold trim - Google Patents

Abstract

The present invention relates to a method of manufacturing a press mold for mass production of a hot stamping cold trim, which solves the problem of the durability of a press mold for mass production of a conventional cold trim, .
That is, a first step of diffusing and bonding the steel bodies 100a and 100b, which are different from each other, with a tool steel of super hardness and hot alloy to form a single mold material 100; A second step of grinding the bottom surface (1) and the one side surface (2) of the mold material (100) with the machining allowance (a) (b) in consideration of the amount of deformation during the heat treatment; A third step of processing the remaining edge faces (3) (4) (5) of the mold material 100; A fourth step of machining the reference holes 102 and 103 and the reference plane 6; A fifth step of forming a plurality of bolt holes 105; And a sixth step of three-dimensionally machining the one side surface of the reference hole 102 or 103 around the reference hole 102 or 103; A seventh step of heat-treating the mold material 100; (③) (④) (⑤) shall be polished to a fixed number by applying a correction value based on the numerical value table of measured values according to the machining conditions, and the bottom surface (1) and one side surface And 8th step of wire processing. Accordingly, it is possible to provide a press mold capable of reducing mold development cost and life span by mass-processing 150kg grade steel products at a lower price, thereby maximizing competitiveness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hot stamping cold stamping method,

The present invention relates to a method of manufacturing a press mold for mass production of hot stamping cold trim, and more particularly, to a method of manufacturing a hot stamping cold stamp, which is capable of improving the steel hull strength at a minimum cost through diffusion bonding, And a method of manufacturing a press stamp for mass production of a hot stamping cold stamp capable of extending a mold life.

In the high oil price era, in which oil prices have been steadily rising since 2002, the greatest challenge to improve competitiveness with other companies in the automobile industry is to improve fuel efficiency of vehicles. In order to improve fuel efficiency, Is the most urgent problem.

As a result, parts makers that supply parts to the automobile companies as well as manufacturers that produce automobiles from around the world have developed better materials to reduce the weight of their body parts and improve their durability. And 490MPa (Mega Pascal) → 590MPa → 980MPa, and it has become gradually more robust to produce body parts with various materials.

However, as described above, as the material gradually becomes stronger, it is faced with the problem of moldability which is difficult to mold the material into a desired shape. Accordingly, the hot stamping method And a hot stamp method in which the tensile strength of the material is increased by 150 kg when cooled.

Here, FIGS. 1A and 1B are sectional views showing a state before cutting the edge of a steel material and cutting a steel mold made of a conventional general cold alloy tool steel (SKD-11).

As shown in the figure, when cutting the edge of the product 10 molded in a predetermined shape, the product 10 is a steel plate of 150 kg, the steel mold 20 made of cold alloy tool steel (SKD-11) The trimming cutting operation can not be continued continuously due to the problem of steel stiffness which can not be repeatedly trimming the product 10 of the steel plate product of the predetermined shape of the 150 kg steel sheet, .

In order to solve the above problem, the entire steel mold 20 may be made of ultra-high hardness alloy such as carbide or powder high-speed steel so that the product of 150 kg steel sheet material can be trimmed easily. However, since ultra high hardness alloy is very expensive There is a problem in that the cost of the press die is extremely high, which results in an excessive cost increase of the produced product, which leads to a loss of competitiveness, which is a problem that can not be used.

In view of the above-mentioned problems, some companies use a laser processing machine as shown in the Korean registered utility model No. 0127057 (Publication No.: 1996-004214), which is described in the patent literature of the prior art document, We are mass producing products by laser cutting.

That is, FIG. 2 is a view showing a state in which a rim of a product is cut by a conventional laser processing machine. As shown in FIG. 2, a product formed of a steel plate material of 150 kg is mounted on a work jig 40, ) Is used to cut the laser according to the shape of the product.

However, this is due to the laser cutting along the edges of the molded part of the product, so it takes too much of the cutting time (eg, 50 seconds per part and 50 times of cold pressing) to complete one product, The price of KRW 1,900 per kilogram of cold press type) is excessive, which also causes a lot of cost increase, which ultimately causes a problem of lowering price competitiveness.

Korean Registered Utility Model No. 0127057 (Publication No.: 1996-004214 (Published date: February 14, 1996), name of design: jig for fixing laser cutting parts)

Accordingly, the present invention has been developed to overcome the problems of the press cutting method using a conventional general steel mold or the laser cutting method. The object of the present invention is to provide a hot stamping type And to provide a manufacturing method of a press stamping die for mass production of hot stamping cold stamp which can provide a press die at a lower price to extend the service life while reducing mold development cost.

The above object of the present invention is achieved by a process for manufacturing a press mold for mass production of hot stamping cold stamps by diffusion bonding two different steel bodies with ultrahigh hardness (cemented carbide) and hot alloy tool steel (SKD-61) The method comprising: A second step of grinding the bottom surface and one side surface of the mold material with a machining allowance considering the amount of deformation during the heat treatment; A third step of processing the remaining edge face of the mold material; A fourth step of machining the reference hole and the reference surface; A fifth step of forming a plurality of bolt holes having a bolt head mounting groove portion; And a sixth step of three-dimensionally machining the one surface around the reference hole; A seventh step of heat-treating the mold material; An eighth step of grinding the bottom surface and the one side surface with machining allowance by applying a correction value based on the numerical value table of the measured values according to the machining conditions, and the remaining edge surfaces being machined by wire; . ≪ / RTI >

According to the manufacturing method of the present invention, since the mold body is manufactured from a general alloy tool steel material and an ultra-high hardness alloy material body in the production of a press mold for cold trim mass production, It is possible to provide a press mold that can be cut in a large amount, thereby achieving an effect of maximizing the mass productivity.

The press mold made of the dissimilar material of the present invention can reduce the development cost of the mold and extend the life of the mold as much as possible, so that it is possible to achieve a considerable cost reduction in mass production of the cold trim product, .

FIGS. 1A and 1B are steel molds made of a conventional general cold alloy tool steel (SKD-11) material,
2 is a view showing a state in which a rim of a product is cut by a conventional laser processing machine
3 is a process block diagram showing the process of manufacturing the press mold of the present invention
Figure 4 is a perspective view of a different steel body for the production of the press die of the present invention.
5A to 5D are diagrams showing a process of manufacturing the press mold of the present invention
6 is a side cross-sectional view showing the press mold used for mass production of the hot stamping cold stamp of the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a process block diagram showing a process for manufacturing a press stamp for mass production of a hot stamping cold stamp of the present invention.

As shown in the figure, the hot stamping cold stamping press mold manufacturing method of the present invention is made through the "design → pattern → casting → machining → finish" process step in order. After that, the produced molds are shipped to the ordering place through the "spotting" process to check whether they are correctly mounted in the correct position and the "trialout" process, which is a test process to check whether the press cutting is actually done properly.

Here, the "design" is a process of creating a drawing for producing a mold, and the design drawing can be operated in 2D or 3D.

The "pattern" is a step of fabricating the same size as an actual mold using a straw according to the designed drawings.

The above-mentioned "casting" is a step of putting a pattern made by stringing into a flask, sanding it with sand, and pouring the casting liquid to produce a steel body having the same shape as the pattern.

The above-mentioned "processing" is a step of machining the bottom surface and the shape of the six surfaces so as to form a predetermined shape in order to assemble various parts and other steel to a steel body made of cast iron or the like.

The "drawing" is a step of finely finishing a hole edge, a corner portion, and the like of a mold that has been subjected to various types of processing in a predetermined form in a processing step with a tool such as a grinder.

The remaining process steps except for the "processing" process step are not significantly different from the manufacturing process of the general press die.

However, the "processing" process in the present invention requires a complicated processing process compared to a cutting mold made of a general cold alloy tool steel (SKD-11) because it needs to overcome the material problem of the steel to be cut. Can be said to be a characteristic part of

FIGS. 5A to 5D are views illustrating a process of manufacturing the press mold according to the present invention. Referring to these drawings, the press mold of the present invention will be described with reference to FIGS. The manufacturing method will be described step by step as follows.

The first step (joining step of the heterogeneous steel body)

The steel material for manufacturing a mold according to the present invention comprises two steel bodies 100a and 100b which are dissimilar materials as shown in Fig.

That is, the steel body 100a on one side forming the front end portion 101 of the metal mold is formed of ultra-high hardness steel material such as carbide or powder high-speed steel, and the other steel body 100b constituting the remaining portion is formed of ultra- 61, which is a hot-alloy tool steel in which the molecular element mixing with the alloy is well performed.

The two steel bodies 100a and 100b provided as described above can be manufactured by surface-machining the reference joint surfaces (surfaces to be bonded to each other) and then bonding the surface-processed joint surfaces to each other, The steps of joining the steel bodies 100a and 100b to the single mold material 100 forming the hexahedron are performed.

The joining step of the two steel bodies 100a and 100b as the dissimilar materials may be performed by a well known diffusion bonding or brazing joint so that both steel bodies 100a and 100b are bonded to the mold material 100 of one body So as to be integrally joined.

That is, the diffusion bonding is a method in which a bonding surface between a steel body 100a of a super-high hardness material and an alloy steel body 100b made of alloy steel is closely contacted and heated in a vacuum state, Quenched and quenched so that the molecular elements of the steel bodies 100a and 100b which are in contact with each other are joined together while being mixed with each other.

Such a diffusion bonding is described in detail in "Method of diffusion bonding of a cemented carbide material" in Patent Registration No. 306493 (Publication No. 10-1999-0045905) owned by the present applicant. .

In addition, the brazing joint means that the insert material for brazing is inserted between the joint surfaces of the dissimilar materials and the insert material is melted to bond the two steel bodies, which are different materials, when heated in a furnace. A detailed description will be omitted.

The second step (bottom and edge face machining steps)

The steel bodies 100a and 100b made of different materials are bonded together to form a single mold material 100 as shown in FIG. 4 (B) (1) and the bottom surface (1) are polished.

At this time, when machining the bottom face (1) and one side face (2), the machining allowance (a) (b) of a certain thickness is to be polished while considering the amount of deformation during the heat treatment.

Therefore, it is possible to apply the correction value considering the measurement value according to the deformation amount and the processing condition at the time of the following heat treatment.

Step 3 (remaining edge face machining step)

(③) (④) (⑤) except for the edge face (②) among the edge faces of the four sides having the joining portions of both steel bodies 100a and 100b are milled.

As shown in FIG. 5A, the opposite side surfaces (3) and (4) facing each other are not assembled surfaces, so they are processed to a width (e) ⑤) is machined including machining allowance (c) for wire machining.

Therefore, it is possible to apply the correction value according to the measurement value according to the machining conditions at the time of the processing after the heat treatment operation described below.

Fourth step (reference plane and reference hole machining step)

This step is a step of machining the reference holes 102 and 103 and the reference plane 6 in which the guide pin is inserted as shown in FIG.

The reference surface 102 is machined to have a step 104 in the range of the ultra-hardness steel body 100a. The reference surface 102 is machined in consideration of a predetermined machining allowance d during polishing. do.

Thus, since the tips of the reference holes 102 and 103, in which tension is concentrated at the time of being fitted to the guide pins, have durability due to ultra-high hardness materials, the life of the mold can be prolonged.

Fifth step (mold clamping ball processing step)

5B, a plurality of bolt holes 105 for inserting the mold through the reference surface 6 and the bottom surface 1 of the mold material 100 joined by the single body are drilled and bored (Not shown).

As shown in FIG. 5B, the bolt holes 105 of the bolt holes 105 of the steel bodies 100a and 100b, which are different materials, are inserted into the bolt holes 105, Hardness steel body 100a at the maximum height so as to be positioned at the site of the ultra-high hardness steel body 100a.

In the sixth step (three-dimensional shape processing step of the reference plane)

In this step, as shown in FIG. 5C, the reference surface (⑥), which is one surface of the steel body 100a of the ultra-high hardness material among the mold materials 100, is processed into a three-dimensional shape in a predetermined shape on the basis of the two reference holes 102 So as to form a predetermined shape.

Step 7 (heat treatment step)

In this step, the hardness of the steel bodies 100a and 100b constituting the metal mold 100 is maximized by performing the heat treatment for performing the quenching operation in which the metal mold 100 made of the predetermined shape is heated to a high temperature and quenched .

Step 8 (correction value (tolerance) application processing step)

In this step, as shown in FIG. 5D, in the sixth step of the heat-treated mold material 100, the second step of the second step, which has been ground with the predetermined machining allowance a and b in the second step, And polishing the surface (1) and the one side edge face (2) with a fixed number by applying a correction value (tolerance) based on the numerical value table of the measured value according to the processing conditions.

In addition, the remaining edge faces (③) (④) (⑤) and the one side face portions of the mold material (100) of the edge faces having the joints of the steel bodies 100a and 100b of the mold material 100 (Tolerance) according to the numerical values of measured values according to the measured values, thereby processing the front end portion 101 and the groove portion 107 of a predetermined shape into a fixed number by wire processing.

Here, the shaded portions of the side surfaces of the reference holes 102 and 103 need not be wire-processed, and therefore, it is desirable to complete the work with a rapid milling process.

The machining allowances (a), (b), (c), and (d) in the second, third, and fourth steps are preferably in the range of 0.1 mm to 1.0 mm, depending on the rigidity of the material.

If the working margin is less than 0.1 mm depending on the kind of material, the amount of thermal deformation of the bottom surface (1) of the mold material (100) and the one side surface (2) during the heat treatment may exceed the thickness (0.1 mm) If the machining allowance exceeds 1.0 mm, the machining allowance (a) (b) ((b)) becomes too large because the machining allowance applied to the machining allowance is too large. c) It is preferable to keep (d) within the range of 0.1 to 1.0 mm depending on the kind of the material.

As described above, the two steel bodies 100a and 100b, which are different materials, are polished and wire-processed on six surfaces by the first to eighth steps of forming a single body mold material 100 by diffusion bonding It is possible to mass-cut 150kg grade steel products in a satisfactory manner, thereby improving mass productivity and providing a press die for mass production of hot stamping cold trim, which reduces development cost and prolongs life span, at a lower cost.

100: mold material 100a, 100b: different type of steel body
101: front end 102, 103: reference hole
104: Step 105: Bolt hole
106: bolt head mounting groove 110: joint surface
①: bottom surface ②, ③, ④, ⑤:
⑥: Reference plane a, b, c, d: Machining allowance
e: Width

Claims (6)

delete Hot Stamping Cold Trim In producing a press mold for mass production,
A first step of joining the ultra high hardness steel body 100a and the hot alloy tool steel body 100b, which are different from each other, to each other to form a monolithic mold material 100;
A second step of grinding the bottom surface (1) and the one side surface (2) of the mold material (100) with a machining allowance (a) (b) of a certain thickness in consideration of the amount of deformation during heat treatment;
(3) (4) (5) except for the rim surface (2) among the rim surfaces of the four sides having the joining portion of the mold material 100;
A fourth step of machining the reference holes 102 and 103 for the guide pins and the reference plane 6 thereof;
A fifth step of forming a number of bolt holes 105 passing through the reference surface (6) and the bottom surface (1) of the mold material (100);
A sixth step of three-dimensionally machining the surface of the steel body 100a having the ultra-high hardness material around the two reference holes 102 and 103 to form a predetermined shape;
A seventh step of heat-treating the metal mold 100 having undergone the sixth step;
(1) and one side edge face (2) with the machining allowance (a) and (b) are polished in a fixed number by applying a correction value based on the numerical table of measured values according to the machining conditions, (④) (⑤) is an eighth step of wire processing to form the front end portion 101 of the fixed number,
(3) (4) during processing in the third step is processed to have a width (e) determined in accordance with the number of the corners, and one edge face (5) to be formed in the front end portion (101) (c)
Wherein the reference surface (6) of the reference hole (102) (103) is machined to include a machining allowance (d) during the fourth step of machining.
3. The method of claim 2,
The machining allowances (a), (b), (c) and (d) in the second,
Wherein the mold is formed within a range of 0.1 mm to 1.0 mm depending on the rigidity of the material.
The method according to claim 2 or 3,
The material of the ultrahigh hardness steel body 100a is a cemented carbide,
Wherein the hot-alloyed tool steel body (100b) is made of a steel material of SKD-61.
5. The method of claim 4,
The joining of the steel bodies 100a and 100b, which are different materials of the first step,
Wherein the hot stamping is performed by diffusion bonding.
The method according to claim 2 or 3,
The reference holes 102 and 103 are machined so that the step 104 is provided in the ultra-high hardness steel body 100a at the time of machining,
Wherein the bolt hole (105) is machined so that the bolt head mounting groove (106) is provided on the ultra high hardness steel body (100a) at the time of machining.

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