KR20190012804A - A method and apparatus for processing a fabricated material by a hot processing process fused with electrometic forming using induction heating - Google Patents

Abstract

The present invention relates to a method to process a workpiece through a hot processing process fused with electromagnetic forming using induction heating and an apparatus thereof. According to the present invention, the method comprises: a step 1) of placing a workpiece in a heating coil; a step 2) of uniformly heating the workpiece to a processing temperature at which internal flowing stress of the workpiece is lowered to be sufficient to improve formability; a step 3) of placing the heated workpiece on an electromagnetic forming side; a step 4) of generating electromagnetic forming force in the transferred workpiece to form the workpiece; and a step 5) of cooling the workpiece. According to the present invention, a workpiece previously heated at a forming temperature is electromagnetically formed, thereby providing advantages of preventing a spring back phenomenon of the workpiece in accordance with electromagnetic forming, and being advantageous to overcome a wrinkle phenomenon as well as having high formability.

Description

Technical Field [0001] The present invention relates to a method and apparatus for machining a workpiece through a hot working process that is combined with electromagnetic forming using induction heating.

The present invention relates to a method and apparatus for machining a workpiece through a hot working process that is combined with electromagnetic forming using induction heating, and more particularly, to a method and apparatus for processing a workpiece by induction heating A method for machining a workpiece through a hot working process which is fused with electromagnetic forming using induction heating for facilitating the molding of a gigantic steel material by sequentially processing the material by an electromagnetic electromagnetic (EMF) processor ≪ / RTI >

The global automobile industry faces the greatest upheaval in the world due to international environmental regulations and fuel price trends and rising energy prices.

GHG emissions from the transport sector in all of the global industrial sectors are 25%, and each country is strengthening regulations for greenhouse gas emission control while strengthening automobile fuel efficiency regulations. By 2025, it is necessary to improve fuel efficiency twice as much. As a result, the fuel efficiency improvement technology will be a key factor in determining the competitiveness of the automobile market.

In order to improve the fuel efficiency of the vehicle, advanced automobile companies are concentrating on improvement of engine / driveline efficiency, reduction of air resistance through aerodynamic design, development of alternative energy and automobile lightening technology. Among these, automobile lightening technology is the most practical alternative And the demand is expected to increase steadily.

In addition, the automobile industry is facing the contradictory situation that the light weight of the vehicle and the safety of collision are improved.

In order to solve such a situation, automobile manufacturers have actively carried out researches for achieving lighter weight of the vehicle while ensuring the collision stability of the vehicle, and as a result, the main members of the vehicle are replaced by high strength steel plates from general body steel plates. Automakers are actively pursuing research to apply high-strength steel sheets to BIW, and material suppliers are continuously developing high-strength steel materials required by automobile manufacturers. In recent years, a gigabit steel material exceeding the strength of AHSS (Advanced High Strength Steel) has been developed and studies are being conducted on the application of gigantic steel material to the body member.

Since most of the major members of the vehicle are produced by the sheet metal forming process, the steel sheet molding process is a key technology for the production and design of sheet metal members.

However, in the case of giga-grade steel, it is known that the productivity and dimensional accuracy of the thin plate member are degraded when the conventional sheet-metal forming method is applied because of high amount of spring back due to high strength and low moldability and low formability.

In order to enhance the collision safety of reinforced C pillar parts, when the gigantic steel material is applied, fracture occurs in the curved surface portion designed for the space efficiency and the curvature radius of the curved portion is increased to prevent fracture The design was modified. In addition, for the application of floor side members of giga-grade steel sheets, it is necessary to reduce the angle of the wall part to which the standard was applied and to modify the design by increasing the curvature radius of the curved part. The conditions are followed.

Therefore, it is necessary to derive a new method for improving the formability of giga-grade steel sheet in order to apply the gigantic steel material of smooth body member.

In the current industry, electromagnetic molding technology is proposed as a way to solve this problem, and studies are underway.

Electroforming is one of impulse forming or high speed forming techniques. It is one of the molding methods in which a strong transition magnetic field is applied directly to the metal to be processed to transform the metal. Electroforming is performed using electromagnetic molding equipment consisting of a high capacity capacitor and a forming coil, a control circuit for charging the capacitor, and a power supply and a switch to generate a strong magnetic field. When the coil discharges the electric current within a short time of a few hundreds of microseconds instantly through the capacitor, induced electromotive force is generated in the surrounding work piece due to the change of the magnetic flux and the induced current flows. The workpiece in which the induced current flows in the magnetic field is subjected to the Lorentz force, and the molding is performed using this force as the forming force.

The advantages and disadvantages of electromagnetic molding according to the characteristics of electromagnetic molding are as follows. In the case of electromagnetic molding, the forming speed is several hundreds of m / s. The strain rate of the workpiece is tens of thousands s ^{- 1} , which leads to the improvement of the formability of the steel sheet due to the high ^- speed forming and to overcome the main defects such as wrinkling and spring - Do.

In addition, there is no physical contact during molding, and thus there are no problems such as surface defects, abrasion, and lubrication due to the contact occurring during the conventional press forming.

However, the forming force due to electromagnetic induction depends on the electric conductivity of the workpiece. Electromagnetic forming is suitable for materials having high electric conductivity and low inductive stress, and the electromagnetic forming is extremely low in efficiency and difficult to implement the deep drawing mode .

In this way, there are disadvantages to be overcome in spite of various advantages of electromagnetic molding, so continuous research and development is required to expand the application of electromagnetic molding.

It is therefore important to find a new approach to electromagnetic molding that utilizes induction heating.

It is an object of the present invention to provide a method and apparatus for machining a workpiece through a hot working process that is combined with electromagnetic forming using induction heating.

It is another object of the present invention to provide a method of manufacturing a semiconductor device that facilitates shaping of a gaseous steel material by sequentially heating the material to a process temperature using induction heating and then sequentially processing the material by an electromagnetic forming (EMF) The present invention provides a method and apparatus for machining a workpiece through a hot working process that is fused with electromagnetic forming using induction heating.

The present invention has the following structure in order to achieve the above object.

A method for processing a workpiece of the present invention includes the steps of: 1) placing a workpiece in a heating coil; 2) uniformly heating the workpiece to a process temperature at which the internal flow stress is low enough to improve the forming force; 3) positioning the workpiece in the heated state on the electromagnetic forming side; 4) generating and forming an electromagnetic forming force on the transferred workpiece; And 5) cooling the workpiece.

In the step 2), the high-frequency current is discharged and heated along the induction heating coil.

In the step 4), pulse energy of high voltage stored in the capacitor is instantaneously applied to the electromagnetic forming coil or the induction heating coil to be molded.

Meanwhile, an apparatus for processing a workpiece using a method for processing a workpiece according to the present invention is characterized in that the apparatus for machining the workpiece includes a fixed die for forming a workpiece, ; A transfer bed for transferring the molding die; A heating means mounted on the transfer bed and arranged in a transfer direction of the molding die to uniformly raise the workpiece to a processing temperature; And molding means for pressing the workpiece heated by the heating means to the molding die side so as to be molded.

The heating means also discharges the high frequency along the induction heating coil to heat the workpiece.

The shaping means instantaneously applies the pulse energy of high voltage stored in the capacitor to the workpiece to form it.

The pulse energy of the high voltage is applied by either the induction heating coil or the electromagnetic forming coil.

The heating means and the molding means each extend outward from the center of the heating means and the molding means and are wound.

According to the present invention, the material is heated to the process temperature using induction heating, and then the material is sequentially processed by an electromagnetic forming (EMF) processor so that the formability of the ultra high rigidity steel or the gigabit steel is improved. There is an effect that can be easily done.

Further, according to the present invention, the workpiece in a state of being heated to the forming temperature in advance is electromagnetically molded, thereby preventing the springback phenomenon of the workpiece due to the electromagnetic molding, and can achieve high moldability, There is an advantage advantageous to overcome.

Further, according to the present invention, since the workpiece is formed in a state in which the flow stress is heated to a processing temperature sufficient for improving the forming force, there is an advantage that the molding efficiency can be increased.

1 is a block diagram illustrating a method for processing a workpiece in accordance with the present invention;
2 is a schematic view showing an apparatus for processing a workpiece according to the present invention;
3 is a schematic view showing a heating means according to the invention;
4 is a schematic view showing a molding means according to the invention;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention can be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments are provided to explain the present invention to a person having ordinary skill in the art to which the present invention belongs. Accordingly, the shape of each element shown in the drawings may be exaggerated to emphasize a clearer description.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

A method for machining a workpiece of the present invention comprises the steps of: 1) positioning a workpiece in a heating coil; 2) uniformly heating the workpiece to a process temperature at which the internal flow stress is low enough to improve the forming force; 3) positioning the workpiece in the heated state on the electromagnetic forming side; 4) generating and forming an electromagnetic forming force on the transferred workpiece; And 5) cooling the workpiece.

The step 1) is a step of fixing a workpiece WP of a predetermined size to a molding die 120 for molding and then entering the molding means 130 and positioned below the induction heating coil. In this step, the workpiece may be fixed to the molding die through a jig or a magnetic force, but it may be seated through a jig (a structure for supporting the rim of the workpiece) for aligning the workpiece so as to prevent the workpiece from shaking.

2) Step S20 is a step of heating the workpiece WP to a temperature sufficient for improving the forming force by heating the workpiece WP by using a high frequency supplied through the high frequency supplying means 134 connected to the induction heating coil. The heating portion of the workpiece is determined by the shape and size of the wound induction heating coil, but may be limited to the portion to be formed. For example, as shown in Fig. 3, heating is performed only in the region A to be formed into the molding die, thereby preventing the use of higher frequency than necessary, thereby improving the efficiency. That is, it is intended to increase the molding efficiency by heating the workpiece to a temperature at which the flow stress of the workpiece is good, thereby improving the moldability of the workpiece.

3) Step S30 is a step S30 in which the molding die 120 on which the workpiece WP heated in Step S20 is conveyed from the heating means 130 to the molding means 140 along the conveying bed 110 . In this step, it is desirable to shorten the distance of conveyance in order to maintain the heating state. For this purpose, it is desirable to minimize the interval between the heating means and the molding means. It is also possible to connect between the heating means and the forming means in a tunnel form so as to minimize the heat loss of the heated workpiece and to arrange a heating zone (not shown) in the tunnel to maintain the temperature of the workpiece Do.

4) Step S40 is a step of applying the electromagnetic forming force from the induction coil to the workpiece side to generate the electromagnetic forming force. 4, an electromagnetic force is generated in the heated workpiece so that the workpiece is pressed toward the molding die of the molding die to be molded into the shape of the molding die.

5) Step S50 is a step of cooling the formed workpiece. In this step, the cooling method is selected according to the demand of the product, which is the completion stage of the product.

When the method of forming a workpiece of the present invention is used, the workpiece can be easily formed, wrinkles and springback phenomenon of the workpiece can be prevented from occurring in the molding process, and the workability It is possible to reduce the production cost due to the processing of the workpiece. Particularly, by continuously performing the induction heating and the electromagnetic forming method, it is possible to advantageously form an ultra-high strength steel or a gaseous steel.

The apparatus for processing a workpiece of the present invention includes a conveying bed 110, a molding die 120, a heating means 130 and a forming means 140 as shown in Fig.

The conveying bed 110 has a predetermined length and a rail 111 extending in the longitudinal direction is disposed on the conveying bed 110 so that the molding die can be conveyed.

Here, the rail 111 may include any structure capable of transferring through the L / M guide but transferring the molding die by preventing the molding die from moving and transferring it.

The shaping die 120 is formed of a conductive material and has a predetermined shaping mold 121 formed on the upper surface thereof. A jig (not shown) for fixing or aligning the workpiece WP around the shaping mold 121, Is disposed. That is, a jig is disposed on the upper surface of the molding die so as to prevent the workpiece from moving.

The heating means 130 is provided with an entrance hole 132 in which the both sides of the housing 131 (the advancing direction of the molding die) are opened, and the induction heating coil 133 . The induction heating coil 133 extends outwardly from the center of the housing and is wound so that the lower surface of the induction heating coil 133 faces the upper surface of the workpiece.

In addition, the high-frequency current is guided from the center to the outside and the workpiece is heated by the eddy current.

The induction heating coils are arranged such that the high-frequency current is mainly applied to the forming region A of the workpiece WP as shown in FIG.

Here, the molding region refers to a portion where the workpiece is molded in the mold.

The forming means 140 is formed by pressing a workpiece heated to a predetermined temperature by a heating means 130 into a mold by using an electromagnetic forming force so that the molding die transferred from the heating means is opened A housing 141 having a hole 142 formed therein and an electromagnetic induction coil 143 disposed inside the housing 141 and extending outward from the center of the housing and wound therearound.

That is, as shown in FIG. 4, the forming unit 140 generates an electromagnetic force applied from a rechargeable battery (not shown) in a state where the electromagnetic induction coil 143 is disposed to face the upper surface of the workpiece, So that the workpiece is pressed into the molding die to be molded.

Hereinafter, an operation state of the present invention will be described with reference to the accompanying drawings.

First, a workpiece WP is placed on a molding die 120 disposed on a transfer bed 110, a workpiece WP is aligned using a jig (not shown) disposed on a molding die, The molding die 120 advances to enter the heating means 130 side.

After entering the heating means 130, a high-frequency current is applied to the induction heating coil 133 side through the high-frequency supply means 134 in accordance with a signal from the control unit so that the high-frequency current flows through the workpiece on the molding die, And heated to the process temperature sufficiently.

Thereafter, the molding die on which the workpiece in a heated state is placed is transferred along the rail 111 to enter the molding means 140. At this time, a tunnel connection line (not shown) may be disposed between the heating means 130 and the molding means 140. This is to prevent the temperature of the workpiece from dropping more than necessary during the transfer process.

Next, the high-voltage pulse energy stored in the capacitor is instantaneously applied to the workpiece heated to the process temperature to the electromagnetic coil side of the forming means to generate an electromagnetic forming force, and the workpiece is pressed toward the forming die of the forming die by the electromagnetic force, It is processed in the form of a mold.

The molded forming die is transported along the rails and discharged from the molding means to cool. At this time, the cooling moves along the rail, and it is moved by slow cooling at room temperature. It moves to the line required for separate commercialization and is cooled according to the cooling method required for commercialization.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. There is no doubt that it is within.

Claims (8)

1) positioning a workpiece in a heating coil;
2) uniformly heating the workpiece to a process temperature at which the internal flow stress is low enough to improve the forming force;
3) positioning the workpiece in the heated state on the electromagnetic forming side;
4) generating and forming an electromagnetic forming force on the transferred workpiece; And
5) cooling the workpiece. ≪ RTI ID = 0.0 > 5. < / RTI > The method according to claim 1,
Wherein the high-frequency current is discharged along the induction heating coil in step 2). The method according to claim 1,
Wherein the step (4) is a step of instantaneously applying high-voltage pulse energy stored in the capacitor to the electromagnetic forming coil or the induction heating coil. An apparatus for processing a workpiece using a method for processing the workpiece according to any one of claims 1 to 3,
An apparatus for processing a workpiece,
A molding die on which a workpiece is placed, forming a certain mold for molding the workpiece;
A transfer bed for transferring the molding die;
A heating means mounted on the transfer bed and arranged in a transfer direction of the molding die to uniformly raise the workpiece to a processing temperature; And
And molding means for pressing the workpiece heated by the heating means to the molding die side so as to form the workpiece. 5. The method of claim 4,
Wherein the heating means discharges a high frequency along the induction heating coil to heat the workpiece. 5. The method of claim 4,
Wherein the shaping means instantaneously applies the high-voltage pulse energy stored in the capacitor to the workpiece to form the workpiece. The method according to claim 6,
Characterized in that the pulse energy of the high voltage is applied by either an induction heating coil or an electromagnetic forming coil. 5. The method of claim 4,
Characterized in that the heating means and the molding means each extend outwardly from the center in the heating means and the molding means and are in the form of a wound.

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