KR102142092B1 - manufacturing method for panel of vehicle using high strength and low specific gravity - Google Patents

Abstract

In order to improve the productivity by reducing the defect rate due to the springback effect, the present invention provides a laser according to the cross-sectional shape of a base panel made of a high-strength, low-weight, light-weight steel material in two dimensions from preset three-dimensional appearance information of a vehicle plate. A first step of cutting with a blanking process; A second step in which the blanked base panel is pressed and formed between a pair of base molds having a surface profile corresponding to the surface profile of the 3D appearance information; And a third step in which the forming base panel is pierced in the vertical direction and the lateral direction according to the location information of the perforated portion calculated from the 3D appearance information. to provide.

Description

{Manufacturing method for panel of vehicle using high strength and low specific gravity}

The present invention relates to a method for manufacturing a plate material for a vehicle using a high-strength low-weight light-weight steel material, and more particularly, to a method for manufacturing a plate material for a vehicle using a high-strength low-weight light-weight steel material having improved productivity by reducing a defect rate due to a springback effect.

In general, a vehicle plate is provided at a lower portion of the vehicle body to prevent deformation due to impact and load and to secure passenger safety.

For example, the vehicle plate includes a front side member, a rear side member, a cross member, a flow panel, a side member extension, and the like, and may be provided in various types according to the position of the engine, the arrangement of magnets, the size of the vehicle, and the like.

Such a vehicle plate material plays an important role for the safety of the occupant or the durability of the vehicle, such as stably supporting the engine, suspension, and driving device, and distributing external forces due to collision or load to other parts of the vehicle body.

On the other hand, such a vehicle plate material is provided with a high-strength steel material having a thicker thickness than the basic body panel, and occupies a large portion of the weight of the vehicle. At this time, the vehicle plate material is manufactured by drawing, etc. In the case of high-strength steel, there is a problem that a large amount of wrinkles is generated in the drawing molding process.

In particular, the vehicle plate material is coupled by welding or bolting in a state of being in close contact with the vehicle body panel, and the space between the vehicle body panel and the vehicle plate material is reduced due to the corrugated surface portion, resulting in a decrease in strength due to the wrinkle portion.

Accordingly, in order to prevent the reduction of the bonding strength or the strength due to the occurrence of wrinkles during molding and to improve the safety of passengers while responding to the trend of reducing fuel consumption of vehicles, recently, a vehicle plate has been manufactured using low specific gravity steel having a high elongation. .

However, in the case of a low specific gravity steel material having a high elongation, there is a problem in that a large number of defective products are generated due to the springback effect that is restored to the shape before molding when a certain period of time has elapsed after being molded into the first designed shape.

In addition, in the case of hot forming to form a steel material at a high temperature in order to prevent the springback effect, a high temperature environment of 900 degrees or more is required, so that the cost of the product is increased due to an increase in manufacturing cost.

Korean Patent Publication No. 10-2015-0047043

In order to solve the above problems, the present invention is to solve the problem by providing a method for manufacturing a vehicle plate using a high-strength low-weight, light-weight steel material that improves productivity by reducing the defect rate due to the springback effect.

In order to solve the above problems, the present invention is a base panel provided with a high-strength, low-weight, light-weight steel material is cut with a laser in accordance with the cross-sectional shape developed in two dimensions from the predetermined three-dimensional appearance information of the vehicle plate material is blanked and processed First step; A second step in which the blanked base panel is pressed between a pair of base molds having a concave-convex portion corresponding to the outer surface profile of the 3D appearance information and forming; And a third step in which the forming processed base panel is pierced in the vertical direction and the lateral direction according to the positional information of the perforated portion calculated from the 3D appearance information, wherein in the second step, the base panel is sharp. A pair of buffers having a surface profile corrected to a third depression depth that is reduced by 20% to 40% from the first depression depth calculated from the surface profile of the base mold to prevent local cracking or damage to the coating interface due to plastic deformation. Pressing between the molds to be pre-processed, and the blocking-processed base panel is downformed to the lower of the upper mold among the base molds along the upper part of the lower mold among the base molds, and pressed through the change of the pressing point. The base plate of the down-form processed jig is fixed so as to maintain the plastic deformation according to the processing, and is closely arranged along the lower portion of the upper mold, but is upformed by the rise of the lower mold, and the base panel is designed for the first time after springback. To have a shape conforming to the above, the base panel is processed with the same machining amount using the first depression depth and the processing temperature as the design variables, and then restored and averaged. And a step of pressing and sequentially processing between a pair of list-driving molds having a surface profile corrected to an increased second depression depth by adding a corresponding deformation amount to the third step, wherein the forming step of the base panel includes The step of taking out from the base mold, and the step of moving and fixing the taken out base panel to a predetermined laser processing position, and detecting the three-dimensional position information of the fixed base panel, according to the detected three-dimensional position information It provides a method for manufacturing a sheet material for a vehicle using a high-strength, low-weight, lightweight steel, characterized in that the machining coordinates corresponding to the punched portion are calculated and include piercing by laser cutting.

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Through the above solution, the present invention provides the following effects.

First, since the base panel is pressed between the base molds facing up and down and processed into a three-dimensional shape corresponding to a vehicle plate material, a separate draw bead is not required unlike the conventional drawing method, so the required area is reduced during blank processing. As a result, manufacturing costs can be reduced.

Second, manufacturing quality is improved by manufacturing a vehicle plate with a high elongation base panel that minimizes defects such as breakage and wrinkles during processing, and the base panel primarily processed as a base mold is transformed with amplified deformation amount through the list riking mold. As the secondary processing, the springback effect is offset, so the defect rate of the product can be reduced and productivity can be improved.

Third, since the base panel is subjected to a predetermined buffering process at a stage before being processed with an amplified deformation amount that can offset the springback effect, defects such as local cracks due to rapid plastic deformation or damage to the coating interface are minimized. Productivity can be significantly improved.

1 is a flow chart showing a method for manufacturing a plate material for a vehicle using a high-strength, low specific gravity, light weight steel according to an embodiment of the present invention.
Figure 2 is a plan view showing a three-dimensional appearance information and a two-dimensional development cross-section of the vehicle plate material in the vehicle plate manufacturing method using a high-strength low specific gravity lightweight steel according to an embodiment of the present invention.
Figure 3 is a side view showing the three-dimensional appearance information of the vehicle plate material in the vehicle plate manufacturing method using a high-strength low specific gravity lightweight steel according to an embodiment of the present invention.
Figure 4 is an exemplary view showing the surface profile of the base mold and the buffer mold in a method for manufacturing a plate material for a vehicle using a high-strength low specific gravity light weight steel according to an embodiment of the present invention.
Figure 5 is an exemplary view showing a process for calculating the average restoration ratio in a method for manufacturing a sheet material for a vehicle using a high-strength, low-weight, lightweight steel according to an embodiment of the present invention.

Hereinafter, a method for manufacturing a plate material for a vehicle using a high strength low specific gravity light weight steel according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart showing a method for manufacturing a plate material for a vehicle using a high strength low specific gravity light weight steel material according to an embodiment of the present invention, and FIG. 2 is a method for manufacturing a plate material for a vehicle using a high strength low specific gravity light weight steel material according to an embodiment of the present invention It is a plan view showing three-dimensional appearance information and a two-dimensional development cross-section of a vehicle plate material, and FIG. 3 is a side view showing three-dimensional profile information of a vehicle plate material in a method for manufacturing a plate material for a vehicle using a high-strength low specific gravity lightweight steel according to an embodiment of the present invention 4 is an exemplary view showing the surface profile of a base mold and a buffer mold in a method for manufacturing a vehicle plate using a high-strength low-weight and light-weight steel according to an embodiment of the present invention, and FIG. 5 is according to an embodiment of the present invention It is an exemplary view showing the process of calculating the average restoration ratio in the method of manufacturing a sheet material for a vehicle using high-strength low-weight and lightweight steel.

1 to 5, a method for manufacturing a plate material for a vehicle using a high-strength, low-weight, lightweight steel of the present invention is made as follows.

First, the base panel provided with a high-strength low-weight light-weight steel material is cut with a laser according to a cross-sectional shape (2) developed in two dimensions from a predetermined three-dimensional appearance information (1) of the vehicle plate material and processed to be blanked (s10). .

Here, the high-strength low specific gravity lightweight steel material means an alloy steel having a high strength of 780 Mpa or more while being light and having a high elongation.

For example, the high strength low specific gravity light weight steel is based on iron (Fe), and carbon (C), silicon (Si), manganese (Mn), aluminum (Al), titanium (Ti), etc. are added to the austenite phase. The ferrite phase may be provided as a material that simultaneously appears at a constant area fraction.

division importance
(kg/cm3) YS
(Mpa) TS
(Mpa) EL(%) U-EL T-EL High strength steel sheet 7.85 500 893 19 Low specific gravity
Lightweight steel 7.1 475 807.5 35.02 41.62

Table 1 compares the physical properties of a conventional high strength steel sheet and a high strength low specific gravity light weight steel used in the present invention.

As shown in Table 1, the high-strength low-specific gravity light-weight steel material exhibits the same level of strength as the high-strength steel sheet, but shows a reduced specific gravity of 10% or more and an improved elongation of more than twice.

In addition, the vehicle plate is preferably understood as a meaning encompassing various body reinforcement parts such as a front side member, a rear side member, a cross member, a flow panel, and a side member extension, and in particular, an extension rear that reinforces both sides of the lower surface of the vehicle body. It can be applied to the floor front.

Here, the base panel means that the high-strength low-weight, light-weight steel is provided in a sheet form, and the 3D appearance information 1 of the vehicle plate material means design information provided as 3D vector data.

In this case, referring to FIG. 2, the 3D appearance information 1 projects the inside except the edge portions 2a, 2b bent in a flange shape along one reference plane, and then the edge portion bent on the projected section ( It can be developed in two dimensions by adding an area of 2a, 2b).

Further, the blanking process may be completed by cutting with a laser along the two-dimensional cross-sectional shape 2 in which the base panel is deployed.

On the other hand, referring to Figure 3, the blanking process (s10) the base panel is pressed between a pair of base molds having a surface profile corresponding to the surface profile (3) of the three-dimensional appearance information is formed (s20) .

Here, the surface profile 3 of the three-dimensional appearance information is preferably understood as a meaning encompassing the bottom surface profile and the top surface profile of the three-dimensional appearance information.

In detail, the base mold is provided with an upper mold and a lower mold, and a molded part corresponding to the three-dimensional appearance information of the plate material for the vehicle may be formed between the upper mold and the lower mold in contact with each other.

At this time, it is preferable to understand the surface profile of the base mold in a sense encompassing the lower surface profile of the upper mold and the upper surface profile of the lower mold.

That is, the upper mold has a lower surface profile corresponding to the upper surface profile of the 3D appearance information 1, and the lower mold is provided to have a upper surface profile corresponding to the lower surface profile of the 3D appearance information 1.

At this time, in a state in which the upper mold and the lower mold are in close contact, a space between the lower surface profile of the upper mold and the upper surface profile of the lower mold is spaced to correspond to the thickness of the base panel or the vehicle plate.

In addition, concave-convex grooves and concave-convex protrusions corresponding to the surface profile 3 of the 3D appearance information 1 may be formed on the surfaces of the upper mold and the lower mold.

For example, if an uneven groove is formed in one mold, uneven protrusions may be formed in a portion corresponding to the uneven groove in the other mold, and the uneven grooves and uneven protrusions are three-dimensional appearance information for a vehicle plate (1) It may be recessed and protruded to correspond to the surface profile 3.

Then, the forming (s20) of the base panel is pierced in the vertical direction and the lateral direction according to the position information of the perforated portion calculated from the three-dimensional appearance information (1) (s30).

That is, when the base panel is processed into a three-dimensional shape corresponding to the vehicle plate 1 through the forming process (s20), the machined base panel pierces the perforated part to be connected with fastening means such as bolts or other parts. As a result, manufacturing of a vehicle plate material can be completed.

As described above, as the base panel is pressed between the molds facing up and down and processed into a three-dimensional shape corresponding to a vehicle plate material, a separate draw bead is not required unlike the conventional drawing method, so the area required for blanking is reduced. As a result, manufacturing costs can be reduced.

On the other hand, the step (s20) of the base panel is press-processed between the base mold preferably includes a down-form processing step and an up-form processing step.

That is, the blanking-processed base panel is disposed along the upper portion of the lower mold among the base molds and is down-formed by descending the upper mold among the base molds, and the down-molded base panel is located at the lower portion of the upper mold. The jig is fixed to be in close contact, and the upform is processed according to the rise of the lower mold.

In detail, the base panel may be processed twice through the base mold in the forming step (s20). At this time, the base panel is arranged in a flat state after blanking so that the rim portion is arranged to be aligned with the rim of the lower mold, and then processed first according to the descending of the upper mold.

In addition, the base panel is disposed in close contact with the lower portion of the upper mold so that the lower surface profile of the upper mold and the primary processed upper surface profile of the base panel are matched in the first processed state according to the surface profile (d) of the base mold. do.

At this time, the base panel is maintained in close contact with the lower surface of the upper mold through a jig device and is processed secondarily according to the rise of the lower mold.

Accordingly, the plastic deformation caused by press working can be more stably maintained through the minute change of the pressing point during the first and second processing, and the effect of minimizing the defect rate of the product is minimized by reducing the change in the processing amount due to springback. Can provide.

On the other hand, referring to Figures 4 to 5, the forming processing step (s20), the forming processing (s20) the base panel of the base mold from the surface profile of the base mold is calculated relative to the base panel from the average recovery ratio by processing temperature It is preferred to include the step of being pressed between a pair of wrist riking molds having a surface profile (d) corrected to an increased depression depth (b) corresponding to.

Here, it is preferable to understand the surface profile of the list riking mold in a sense that encompasses the lower surface profile of the upper list ripping mold and the upper surface profile of the lower list ripping mold.

In detail, the base panel exhibits different springback behavior depending on temperature.

Processing temperature Average restoration rate 20℃ 78% 100℃ 66% 200℃ 50% 350℃ 33% 450℃ 17%

Table 2 shows the ratio of the amount of bending processed to be restored to the shape of a plate by the temperature processed in a state where the base plate of the flat plate was bent at 90 degrees.

In other words, the base panel processed at 90°C at 20°C restored 70° (θ1) after a certain period of time, resulting in a decrease in bending amount of 20°C, and at 100°C, 60°(θ2) was restored to decrease the bending amount at 30°C. .

In addition, 45 degrees (θ3) was restored at 200°C and the amount of bending curvature decreased by 45 degrees, and 30 degrees (θ4) was restored at 350 degrees Celsius to reduce the amount of bending curvature at 60 degrees, and 15 degrees (θ5) was restored at 450°C. As a result, the bending amount was reduced by 75 degrees.

In this case, the average restoration ratio is calculated by processing a plurality of base panels made of the same material and thickness with the same machining amount and restoring, to calculate an average value for the remaining machining amount, and the average restoration ratio can be calculated for each processing temperature. have.

In detail, the surface profile of the base mold is set corresponding to the surface profile 3 of the three-dimensional appearance information 1 for the vehicle plate material, and the surface profile d of the list riking mold is from the surface profile of the base mold. It is amplified and set to correspond to the average restoration ratio for each processing temperature.

That is, the first depression depth a is calculated for a plurality of predetermined points from the surface profile 3 of the 3D appearance information 1 or the surface profile of the base mold, and the plurality of first depressions calculated at each point A plurality of second depression depths b may be calculated by adding a deformation amount corresponding to the average restoration ratio for each processing temperature to the depth a.

Here, the depression depth (a) can be calculated by using the flat portion of the surface profile (3) of the 3D appearance information (1) or the surface profile of the base mold as a reference plane, and the average restoration ratio is the temperature of the actual processing environment. It is preferable to apply a value as a reference.

In addition, the corrected surface profile (d) may be calculated by processing the second depression depth (b) at each point where the deformation amount is added by a 3D rendering technique, etc., and a list-driving mold according to the corrected surface profile (d) It can be designed and manufactured.

For example, when the processing temperature is 200°C during the forming process, when the base mold has a groove recessed to 10 mm at a point, the list riking mold is extended to 15 mm in the portion corresponding to the groove. It has a groove.

That is, the list riking mold is designed as a surface profile (d) having a processing amount amplified from the surface profile of the base mold so as to offset the springback effect, and the amplified processing amount depends on the average restoration ratio considering the processing temperature. Is decided.

In this way, the production quality is improved by manufacturing a vehicle plate with a high elongation base panel that minimizes defects such as breakage and wrinkles during processing, and the base panel primarily processed with the base mold is transformed with amplified deformation amount through the list riking mold. As the secondary processing, the springback effect is offset, so the defect rate of the product can be reduced and productivity can be improved.

That is, the base panel manufactured through the base mold and the list riking mold has a shape conforming to the original design after the springback.

In addition, by using a plurality of first depression depths (a) measured at each part of the surface profile (3) and the target processing temperature as design variables, a variety of products can be processed through a simple three-dimensional image processing process without complicated computation. List riking molds can be easily designed and manufactured.

On the other hand, referring to Figure 4, the step of the base panel is pressed between the base mold (s20) is the blanking of the base panel before the forming step through the base mold surface profile (d) of the base mold It is preferable to further include the step of being pressed between a pair of buffer molds having a surface profile (e) corrected to a depression depth reduced by 20% to 40% from.

That is, the base panel may be pre-processed between the buffer molds, and then formed through the base mold, and list-listed through the list-like mold.

In detail, the buffer mold may be provided as an upper buffer mold and a lower buffer mold, and a blanked base panel may be press-processed between the upper buffer mold and the lower buffer mold.

At this time, it is preferable to understand that the surface profile (e) of the buffer mold encompasses the lower surface profile of the upper buffer mold and the upper surface profile of the lower buffer mold. For example, if a buffering recessed groove is formed in one of the two buffering molds, a buffering protrusion may be formed in another buffering mold corresponding to the buffering recessed groove.

In addition, in the state where the upper buffer mold and the lower buffer mold are in contact with each other, the buffer recesses and grooves are spaced apart to correspond to the thickness of the base panel or the vehicle plate.

Here, the surface profile (e) of the buffer mold is formed to have a depression depth (c) reduced by 20% to 40% from the surface profile of the base mold.

That is, a first depression depth (a) is calculated for a plurality of predetermined points in the surface profile of the base mold, and a plurality of 20% to 40% reductions in the plurality of first depression depths (a) calculated at each point are reduced. The third depression depth c may be calculated.

In addition, the corrected surface profile (e) may be calculated by processing the plurality of reduction-corrected third depression depths (c) using a 3D rendering technique, etc., and the buffer mold is designed and designed according to the corrected surface profile (e). Can be manufactured.

For example, in the case where the base mold has a recessed portion 10 mm from one point, the buffer mold has a groove portion reduced to 6 to 8 mm in a portion corresponding to the groove portion.

At this time, the base panel may be pre-processed through a buffer mold having a relatively low processing deformation amount, and then sequentially processed through a base mold having a relatively high processing deformation amount and a list riking mold.

As described above, since the base panel is subjected to a predetermined buffering process at a stage before being processed with an amplified deformation amount capable of offsetting the springback effect, the occurrence of binding such as local cracks due to rapid plastic deformation or damage to the coating interface can be minimized. have. Due to this, the production rate of defective products can be reduced and the productivity of products can be significantly improved.

At this time, if the correction amount of the surface profile (e) for the buffer mold is less than 20% or exceeds 40%, there is a fear that the buffering effect is insufficient.

On the other hand, the piercing processing step (s30) in which the perforated portion is formed is a step in which the formed base panel (s20) is taken out from the base mold, and the taken out base panel is transferred to a predetermined laser processing position and fixed. It is preferable to include the step and the step of detecting the 3D position information of the fixed base panel but calculating the machining coordinates corresponding to the punched part according to the detected 3D position information to be processed by laser.

In detail, when the forming process through the base mold is completed, the base panel may be taken out as a base mold through a transfer means such as a robot arm or a crane.

And, the taken out base panel can be transferred to a working space equipped with a laser processing device. At this time, the working space may be shared with a working space in which the base panel is blanked (s10), and it is more preferable that a separate working space is provided for a continuous processing process.

In addition, the transferred base panel may be fixed through a jig device provided with an adsorbing plate or a magnetic coupling portion and disposed at a certain position in the working space.

At this time, when the base panel is disposed at a certain position in the work space, 3D position information of the base panel may be detected through a laser sensor or the like provided in the work space.

Here, it is preferable that the 3D position information is detected for a feature point in which the surface profile of the base panel and the surface profile of the 3D appearance information of the vehicle plate are mutually aligned/comparable, and when calculated in 3 or more places, the surface of the base panel Profiles and three-dimensional appearance information of the vehicle plate can be matched in one coordinate system.

Then, a machining coordinate corresponding to the punched portion is calculated according to the detected 3D location information and is cut by laser. That is, the area and position of each punched portion calculated from the 3D appearance information of the vehicle plate material can be calculated as processing coordinates for the base panel disposed in the working space according to the 3D location information.

At this time, a laser cutting process is performed on the machining coordinates to form a punched portion in the base panel.

As described above, since the machining coordinates corresponding to the perforated portion of the 3D appearance information are calculated based on the 3D position detected with respect to the base panel, a perforated portion is formed through laser cutting, so that defects due to high elongation of the base panel during shear processing Precise piercing processing can be prevented.

As described above, the present invention is not limited to each of the above-described embodiments, and it is possible to be modified by a person skilled in the art to which the present invention pertains without departing from the scope of the claims of the present invention. And, such modifications are included in the scope of the present invention.

1: 3D outline information of vehicle plate material s10: Blanking processing
s20: Foaming s30: Piercing

Claims (5)

A first step in which the base panel provided with a high-strength, low-weight, light-weight steel material is cut with a laser according to a cross-sectional shape developed in two dimensions from preset three-dimensional appearance information of a vehicle plate material and processed into a blanking process;
A second step in which the blanked base panel is pressed and formed between a pair of base molds having a surface profile corresponding to the surface profile of the 3D appearance information; And
A third step in which the forming base panel is pierced in the vertical direction and the lateral direction according to the positional information of the perforated portion calculated from the 3D appearance information,
In the second step, the third depression is reduced by 20% to 40% from the first depression depth calculated from the surface profile of the base mold to prevent local cracks or damage to the coating interface due to rapid plastic deformation of the base panel. Pressing between a pair of buffer molds having a depth-corrected surface profile and pre-processing, and the blanked base panel is downformed by descending the upper mold among the base molds along the upper portion of the lower mold among the base molds. Processed, the base panel is jig-fixed so that the plastic deformation according to press processing is maintained through the change of the pressing point is placed in close contact along the lower portion of the upper mold, but up-formed by the rise of the lower mold and , After the base panel has a shape conforming to the initial design after the spring back, using the first depression depth and processing temperature as design variables, the base panel is processed and restored to the same processing amount, and then the residual processing amount And a step in which the average value is calculated by adding a deformation amount corresponding to the average restoration ratio for each processing temperature and sequentially pressed between a pair of list-driving molds having a surface profile corrected to an increased second depression depth,
In the third step, the forming the base panel is taken out from the base mold, the taken out base panel is transferred to a predetermined laser processing position and fixed, and the three-dimensional position of the fixed base panel A method of manufacturing a plate material for a vehicle using high-strength low-weight and lightweight steel, characterized in that information is detected, and processing coordinates corresponding to the perforated portion are calculated and pierced by laser cutting according to the detected 3D location information. . delete delete delete delete

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