Method for forming surface fillet through laser quenching for automobile stamping die

Abstract

The invention discloses a method for laser quenching of a formed surface fillet for an automobile stamping die, relates to the technical field of laser quenching of a formed surface of a stamping die, and mainly aims to solve the problem that the quenching performances of an inner circle and an outer circle of the fillet are different when the fillet of the formed surface of the automobile stamping die is subjected to laser quenching at present. The method comprises the following steps that baffle plates are attached to a non-quenching area on the outer circle side in a fillet quenching area of a mold, a laser quenching head which is subjected to homogenization treatment and temperature-laser power closed-loop control is adopted, the baffle plates and the fillet quenching area are regarded as an integral face, and laser path design and laser quenching are conducted. The invention provides a laser quenching forming surface fillet method for an automobile stamping die, which can realize uniform quenching of a fillet of a die forming surface and avoids the condition of over-burning of an inner circle or insufficient quenching of an outer circle.

Description

Technical Field

[0001] This invention relates to the field of laser hardening technology for the forming surface of stamping dies, and particularly to a method for laser hardening the rounded corners of the forming surface of automotive stamping dies. Background Technology

[0002] To improve the hardness and wear resistance of the forming surface, automotive stamping dies need to be hardened, and laser hardening is a commonly used hardening method.

[0003] Currently, common laser hardening systems include: a laser (maximum laser power greater than 4kW), a laser hardening head, a transmission beam, a six-axis industrial robot (which drives the laser hardening head to achieve the hardening trajectory movement), and a water chiller (for cooling the laser and the laser hardening head). Its working principle is as follows: A red guide beam directs the laser spot emitted by the laser hardening system to irradiate the forming surface of the automotive stamping die, generating heat in the irradiated area. Then, when the temperature sensor on the laser hardening head detects that the temperature within the red guide beam range has reached the target, the laser spot is removed, and the previously irradiated area cools rapidly, thus achieving the hardening of the forming surface of the automotive stamping die.

[0004] In laser hardening of the rounded corners on the forming surface of automotive stamping dies, the laser spot moves along the extension path of the rounded corner (i.e., along the arc direction). However, because the inner and outer circles of the rounded corner are different in size, the laser energy absorbed by the inner and outer circles of the rounded corner is different in the same amount of time—the inner circle receives more energy per unit area, resulting in different hardening performance between the inner and outer circles of the rounded corner, which may lead to overheating of the inner circle or underhardening of the outer circle. Summary of the Invention

[0005] The purpose of this invention is to provide a method for laser hardening the rounded corners of the forming surface of an automotive stamping die, which can achieve uniform hardening of the rounded corners of the die forming surface and avoid overheating of the inner circle or insufficient hardening of the outer circle.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is: a method for laser hardening of the rounded corner of the forming surface of an automotive stamping die, wherein a shielding plate is attached to the non-hardening area on the inner and outer circular sides of the rounded corner hardening area of ​​the die, and a laser hardening head with homogenization treatment and temperature-laser power closed-loop control is adopted, and the shielding plate and the rounded corner hardening area are regarded as a whole surface for laser path design and laser hardening.

[0007] As a further improvement of the present invention, it specifically includes the following steps: S1. Cleaning: Clean the surface of the laser-quenched mold with alcohol to remove oil and dirt, and wait for it to dry; S2. Prepare the shielding plate: overlap and bond the high reflectivity material plate and the heat insulation material plate to form a shielding plate, and make a notch on the surface of the shielding plate that matches the shape of the rounded corner quenching zone. The dimensional difference between the inner edge of the notch and the outer edge of the rounded corner quenching zone should be controlled within 0mm-0.5mm. S3. Attach the shielding plate: Attach one side of the heat insulation material plate of the shielding plate prepared in S2 to the surface of the non-quenched area of ​​the mold that needs to be shielded, and align the notch on the shielding plate with the rounded corner quenching area so that the rounded corner quenching area can be fully exposed from the notch. S4. Planning the scanning path: Treat the shielding plate and the rounded corner hardening area as a whole surface, and divide the whole surface into multiple processing areas arranged in sequence along the horizontal direction. Then, according to the method of laser hardening each processing area in sequence, set the running program of the six-axis industrial robot to realize the scanning path. S5. Temperature measurement point setting: Turn on the laser power, turn on the red guide light, and align the temperature measuring instrument installed on the laser quenching head within the range of the red guide light to ensure that the temperature measurement point is in the quenching area. S6. Set quenching process parameters: Set the quenching temperature on the temperature controller, set the scanning speed and processing height of laser quenching, and ensure that the focus is located on the surface of each processing area; S7. Start the laser quenching system to complete the laser quenching of the mold. During the quenching process, the temperature measurement results should be compared with the set value to ensure that the actual temperature error is within ±3%. S8. Remove the cover and clean the covered area with alcohol to ensure cleanliness; S9. Test the hardness of the fillet hardening zone to ensure that the hardness reaches HRC50-HRC55.

[0008] As a further improvement of the present invention, the high reflectivity material plate is made of copper plate with a thickness of 0.5mm-3mm, and the heat insulation material plate is made of mold heat insulation plate with a thickness of 5mm-10mm.

[0009] As a further improvement of the present invention, the size of the mold heat insulation plate is not greater than the size of the copper plate, and the size difference between the two is 0mm-1mm.

[0010] As a further improvement of the present invention, the mold heat insulation plate is composed of glass fiber, high-temperature resistant resin and silicon dioxide powder.

[0011] As a further improvement of the present invention, the high-reflectivity material plate and the heat insulation material plate are bonded together with AB glue, and the heat insulation material plate and the mold are bonded together with a low-tack material.

[0012] As a further improvement of the present invention, the laser is a semiconductor laser with a wavelength range of 900nm-1080nm.

[0013] As a further improvement of the present invention, the light spot emitted by the laser quenching head is a rectangular light spot.

[0014] As a further improvement of the present invention, the length of the rectangular light spot is 20±1mm and the width is 5±1mm.

[0015] As a further improvement of the present invention, the quenching temperature in step S6 is set to 850℃-950℃; the scanning speed of the laser quenching head is 3mm / s-6mm / s, and the focal length is 160mm.

[0016] Beneficial effects Compared with the prior art, the advantages of the laser hardening forming surface fillet method for automotive stamping dies of the present invention are as follows: In this method, since the laser path is designed for the entire surface of the shielding plate and the rounded corner quenching area, the laser spot will only pass through the rounded corner quenching area rather than move along the extension direction of the rounded corner quenching area. Therefore, using this method for laser quenching of the rounded corner quenching area will not cause the problem of "different laser energy absorbed by the inner and outer circles of the rounded corner at the same time". This will prevent the surface quality of the rounded corner from being unqualified due to overheating of the inner circle, or the hardness and wear resistance of the rounded corner from being insufficiently quenched of the outer circle. In this way, uniform quenching of the rounded corners of the mold forming surface can be achieved.

[0017] The invention will become clearer from the following description, taken in conjunction with the accompanying drawings, which are used to explain embodiments of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 One of the schematic diagrams showing the distribution of the baffle plate and the rounded corner quenching zone; Figure 2 This is the second schematic diagram showing the distribution of the baffle plate and the rounded corner quenching zone.

[0020] Wherein: 1-rounded corner quenching zone; 2-shielding plate. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; of course, they can also refer to a mechanical connection or an electrical connection; furthermore, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0024] Example Specific embodiments of the present invention are as follows: Figure 1-2 As shown, a method for laser hardening of rounded corners of forming surfaces for automotive stamping dies is described. The method involves attaching a shielding plate 2 to the non-hardening areas on the inner and outer circular sides of the rounded corner hardening zone 1 of the die made of QT700 material, and using a laser hardening head with homogenization treatment and closed-loop temperature-laser power control. The shielding plate 2 and the rounded corner hardening zone 1 are regarded as a whole surface, and laser path design and laser hardening are performed.

[0025] The method includes the following steps: S1. Cleaning: Clean the surface of the laser-quenched mold with alcohol to remove oil and dirt, and wait for it to dry; S2. Prepare shielding plate 2: Overlap and bond the high reflectivity material plate and the heat insulation material plate to form shielding plate 2, and make a notch on the surface of shielding plate 2 that matches the shape of the rounded corner quenching area 1. The dimensional difference between the inner edge of the notch and the outer edge of the rounded corner quenching area 1 should be controlled within 0mm-0.5mm to form complete or most of the shielding of the non-quenching area. S3. Attaching shielding plate 2: Attach one side of the heat insulation material plate of shielding plate 2 prepared in S2 to the surface of the non-quenching area that needs to be shielded in the mold, and align the notch on shielding plate 2 with the rounded corner quenching area 1 so that the rounded corner quenching area 1 can be fully exposed from the notch. S4. Planning the scanning path: Treat the shielding plate 2 and the rounded corner hardening area 1 as a whole surface, and divide the whole surface into multiple processing areas arranged in sequence along the horizontal direction. Then, according to the method of laser hardening each processing area in sequence, set the running program of the six-axis industrial robot to realize the scanning path. S5. Temperature measurement point setting: Turn on the laser power, turn on the red guide light, and align the temperature measuring instrument installed on the laser quenching head within the range of the red guide light to ensure that the temperature measurement point is in the quenching area. S6. Set quenching process parameters: Set the quenching temperature on the temperature controller, set the scanning speed and processing height of laser quenching, and ensure that the focus is located on the surface of each processing area; S7. Start the laser quenching system to complete the laser quenching of the mold. During the quenching process, the temperature measurement results should be compared with the set value to ensure that the actual temperature error is within ±3%. S8. Remove the shielding plate 2 and clean the shielded area with alcohol to ensure cleanliness; S9. Test the hardness of the fillet hardening zone 1 to ensure that the hardness reaches HRC50-HRC55.

[0026] This method involves attaching a shielding plate 2 to the non-quenching zone and treating the shielding plate 2 and the rounded corner quenching zone 1 as a single surface for laser path design. Combined with a laser quenching head that features homogenization treatment and closed-loop temperature-laser power control, it enables laser quenching of the entire surface formed by the shielding plate 2 and the rounded corner quenching zone 1. After laser quenching, simply removing the shielding plate 2 yields a uniformly quenched rounded corner on the mold forming surface.

[0027] In this process, since the laser path is designed for the entire surface of the shielding plate 2 and the rounded corner quenching area 1, the laser spot will only pass through the rounded corner quenching area 1 instead of moving in an arc along the extension direction of the rounded corner quenching area 1. Therefore, using this method to perform laser quenching of the rounded corner quenching area 1 will not cause the problem of "different laser energy absorbed by the inner and outer circles of the rounded corner at the same time". This will prevent the surface quality of the rounded corner from being unqualified due to overheating of the inner circle, or the hardness and wear resistance of the rounded corner from being insufficiently quenched of the outer circle. In this way, uniform quenching of the rounded corners of the mold forming surface can be achieved.

[0028] Meanwhile, the laser quenching head employing homogenization treatment features a flat-top laser energy distribution, ensuring uniform energy distribution across the laser spot and thus guaranteeing quenching quality. Furthermore, the laser quenching head using temperature-laser power closed-loop control can adjust the laser power in real time, ensuring that the actual quenching temperature matches the set temperature.

[0029] In this method, the highly reflective material plate is made of copper, with a thickness of 0.5mm-3mm and a maximum heat resistance temperature exceeding 300℃. The heat insulation material plate is a mold heat insulation plate with a thickness of 5mm-10mm. The size of the mold heat insulation plate is no larger than that of the copper plate, with a size difference of 0mm-1mm. Furthermore, the highly reflective material plate and the heat insulation material plate are bonded together using AB adhesive; the heat insulation material plate and the mold are bonded together using a low-tack material. In this embodiment, the mold heat insulation plate is composed of 30%-60% glass fiber, 25%-40% high-temperature resistant resin, and 6%-12% silica powder.

[0030] The laser quenching system comprises a high-precision dual-color thermometer, a temperature controller, and a laser. The high-precision dual-color thermometer has a temperature measurement accuracy of 0.3% + 2K of the set value. In operation, the system measures the temperature of the laser quenching zone and sends it back to the temperature controller. The temperature controller compares the measured temperature with the set value and calculates the corresponding value, then sends a laser power signal to the laser. This adjusts the laser power, ensuring the measured temperature matches the set temperature, thus achieving closed-loop temperature-laser power control.

[0031] The laser in this embodiment is a semiconductor laser with a wavelength range of 900nm-1080nm. The laser quenching head emits a rectangular spot with a length of 20±1mm and a width of 5±1mm. The laser energy distribution is flat-topped, ensuring uniform energy distribution throughout the laser spot. Furthermore, the laser quenching temperature in this embodiment is set to 850℃-950℃; the scanning speed of the laser quenching head is 3mm / s-6mm / s, and the focal length is 160mm.

[0032] The present invention has been described above in conjunction with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations made in accordance with the essence of the present invention.

Claims

1. A method for laser hardening and rounding the corners of a forming surface in an automotive stamping die, characterized in that, A shielding plate (2) is attached to the non-quenching area on the inner and outer circular sides of the rounded corner quenching area (1) of the mold, and a laser quenching head with homogenization treatment and temperature-laser power closed-loop control is used to treat the shielding plate (2) and the rounded corner quenching area (1) as a whole surface for laser path design and laser quenching.

2. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 1, characterized in that, Specifically, it includes the following steps: S1. Cleaning: Clean the surface of the laser-quenched mold with alcohol to remove oil and dirt, and wait for it to dry; S2. Prepare the shielding plate (2): overlap and bond the high reflectivity material plate and the heat insulation material plate to form the shielding plate (2), and open a notch on the shielding plate (2) that matches the shape of the rounded corner quenching area (1). The dimensional difference between the inner edge of the notch and the outer edge of the rounded corner quenching area (1) should be controlled within 0mm-0.5mm. S3. Attach the shielding plate (2): Attach one side of the heat insulation material plate of the shielding plate (2) prepared in S2 to the surface of the non-quenching area that needs to be shielded in the mold, and make the notch on the shielding plate (2) correspond to the rounded corner quenching area (1) so that the rounded corner quenching area (1) can be fully exposed from the notch. S4. Planning the scanning path: The shielding plate (2) and the rounded corner quenching area (1) are regarded as a whole surface, and the whole surface is divided into multiple processing areas arranged in sequence along the horizontal direction. Then, the running program of the six-axis industrial robot is set according to the method of laser quenching each processing area in sequence to realize the scanning path. S5. Temperature measurement point setting: Turn on the laser power, turn on the red guide light, and align the temperature measuring instrument installed on the laser quenching head within the range of the red guide light to ensure that the temperature measurement point is in the quenching area. S6. Set quenching process parameters: Set the quenching temperature on the temperature controller, set the scanning speed and processing height of laser quenching, and ensure that the focus is located on the surface of each processing area; S7. Start the laser quenching system to complete the laser quenching of the mold. During the quenching process, the temperature measurement results should be compared with the set value to ensure that the actual temperature error is within ±3%. S8. Remove the shielding plate (2) and clean the shielded area with alcohol to ensure cleanliness; S9. Test the hardness of the fillet quenching zone (1) to ensure that the hardness reaches HRC50-HRC55.

3. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 2, characterized in that, The high-reflectivity material plate is made of copper plate with a thickness of 0.5mm-3mm, and the heat insulation material plate is made of mold heat insulation plate with a thickness of 5mm-10mm.

4. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 3, characterized in that, The size of the mold heat insulation plate is no larger than the size of the copper plate, and the size difference between the two is 0mm-1mm.

5. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 3, characterized in that, The mold insulation plate is composed of glass fiber, high-temperature resistant resin and silicon dioxide powder.

6. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to any one of claims 2-5, characterized in that, The high-reflectivity material plate and the heat insulation material plate are bonded together with AB glue, and the heat insulation material plate and the mold are bonded together with a low-tack material.

7. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 2, characterized in that, The laser is a semiconductor laser with a wavelength range of 900nm-1080nm.

8. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 1, characterized in that, The laser quenching head emits a rectangular light spot.

9. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 8, characterized in that, The rectangular light spot has a length of 20±1mm and a width of 5±1mm.

10. The method for laser hardening and rounding the corners of the forming surface of an automotive stamping die according to claim 2, characterized in that, The quenching temperature in step S6 is set to 850℃-950℃; the scanning speed of the laser quenching head is 3mm / s-6mm / s, and the focal length is 160mm.

Images