Mold device capable of realizing positioning detection of thermoforming blank and positioning detection method thereof

Abstract

The present invention provides a mold device and a positioning detection method thereof that can realize positioning detection of hot forming blanks, and belongs to the field of hot stamping forming technology. The mold device includes a mold, and the mold includes an upper mold and a lower mold. The lower mold is provided with a plurality of positioning pins with built-in light sources, and the upper mold cavity is provided with a plurality of camera modules. The camera modules are linked with the hydraulic press and the alarm through the main control machine. The positioning detection method includes the steps S1: preparation; S2: image acquisition; S3: image processing; S4: positioning situation judgment; S5: according to the judgment result of S4, linking the hydraulic press to perform stamping or the alarm to sound an alarm. The present invention can automatically perform visual detection on the blank placement effect, and automatically perform stamping or alarm according to the detection result, thereby ensuring the efficiency and accuracy of the detection, eliminating the corresponding labor costs, ensuring the safety of the operator, and ultimately ensuring the safety of the mold and the normal operation of the hot stamping forming production line.

Description

Technical Field

[0001] The present invention belongs to the technical field of hot stamping, and in particular relates to a mold device capable of realizing positioning detection of hot stamping blanks and a positioning detection method thereof. Background Art

[0002] Hot stamping process is an emerging parts processing method, which has been applied in aerospace, aviation, automobile, anti-corrosion equipment, electrical equipment and daily necessities manufacturing. Especially in the automobile manufacturing industry, parts manufactured using hot stamping process account for about half of the total number of automobile parts, and this process can be specifically used for stamping high-strength steel plates, which plays an irreplaceable role in improving the safety of the vehicle body and achieving lightweight body. Although the application fields of this process are diversified, its specific process is to first heat the blank to a certain temperature, and then use a stamping machine to stamp and quench the corresponding mold, so as to obtain the desired shape and realize the phase change of the metal material at the same time. Based on this, one of the processes is to transfer the heated blank into the mold; however, transfer deviation is very easy to occur in this process, which may cause the stamping process to be suspended or the mold to be damaged. Specifically:

[0003] First, the current method for transferring blanks involves a mechanical gripper grasping and placing them into a mold, which incorporates a mechanical stopper. However, the stopper's ability to correct deviation is limited. In particular, the inconsistent deformation of each batch of blanks after heating causes the mechanical gripper to maintain a different state each time it is grasped, increasing the probability of the blank being misaligned. If a blank is misaligned, the hydraulic press must be paused immediately. Otherwise, the mold will be subjected to abnormal wear or even serious damage, significantly shortening its service life and leading to greater economic losses.

[0004] Therefore, in most hot stamping production lines, an operator is usually present at the hydraulic press to conduct inspections, in order to promptly detect any deviations in the blank and control the start and stop of the stamping press. However, this manual monitoring method is not only highly dangerous but also prone to missed inspections due to operator fatigue. For example, Chinese patent application number CN202210338087 proposes a method for detecting the positioning of hot-formed workpieces in ultra-high-strength hot stamping production lines. This is a relatively complete and reasonable technical solution currently proposed in this field to address the above-mentioned technical issues. This method uses thermal imaging technology to compare the edge information of the inspection template with the actual placed product to determine whether the raw material is accurately placed in the mold. However, the patent overlooks a significant issue that renders this method unfeasible. The heated blank undergoes unstable thermal deformation, causing the blank to be in a different state each time the robot grasps it. Furthermore, the mold cavity typically contains various recessed structures, which can cause the blank to warp, skew, twist, or even hang in mid-air after placement. Furthermore, the infrared thermal imager in the patent is installed above the side of the press, i.e., at an angle, which causes the captured image to be flattened and compressed, resulting in loss of edge information. Furthermore, the principle of the thermal imager is to use radiant heat imaging, but the edges of the blank also experience varying degrees of thermal radiation due to high temperatures, causing the image captured by the thermal imager to expand outward compared to the actual image and fail to properly reflect the actual edge condition of the blank. Therefore, due to the ever-changing posture of the blank and the inherent defects of the thermal imager, this technical solution cannot achieve a standard template for the production of blanks from the same mold. Therefore, it cannot match the template or screen by threshold, and thus cannot fully achieve blank positioning detection.

[0005] In summary, the current technology for positioning detection devices and methods for thermoforming blanks is still a blank area. Therefore, if a practical technical solution can be proposed, it will be of great academic and practical significance. Summary of the Invention

[0006] The purpose of the present invention is to provide a mold device and a positioning detection method thereof that can realize positioning detection of hot forming blanks, so as to solve the following technical problems: In the existing hot stamping forming process, when the blank is transferred, the blank is in different states after being grasped, the mold has limited correction ability, and the manual inspection method is prone to missed detection and high risk, which makes the blank easily deviated, resulting in the need to suspend the stamping process or damage the mold, thereby affecting the normal operation of the hot stamping forming production line or the service life of the mold.

[0007] The present invention is achieved by adopting the following technical solutions:

[0008] A mold device capable of realizing positioning detection of hot-formed blanks comprises a mold, wherein the mold comprises an upper mold and a lower mold, the lower mold is provided with a plurality of positioning pins with built-in light sources, and the upper mold cavity is provided with a plurality of camera modules, which are linked with a hydraulic press and an alarm through a main control machine.

[0009] In the above solution, the traditional mold was redesigned and equipped with positioning pins and a camera module linked to the hydraulic press and alarm, making the mold structure meet the requirements of visual inspection. Based on this, during the blank transfer process, multiple positioning pins can locate the blank in all directions and at multiple angles. The camera module can detect and identify the blank to determine whether it is placed in place. If the blank deviates, the main control machine and alarm will automatically alarm to remind the operator to deal with it in time. The hydraulic press will simultaneously stop stamping, ensuring the safety of the mold. This fully automatic method also eliminates a large amount of manual monitoring costs. Among them, if the blank does not deviate, the positioning pins with light sources will all be inserted into the corresponding positioning holes pre-set on the blank. That is, the positioning pins can play the role of mechanical positioning and light source in this device. The specific number and installation position of the camera modules are determined based on the field of view covering the core on the lower mold surface.

[0010] Furthermore, the camera module includes several mounting shells, each mounting shell is provided with a group of camera components, and the several groups of camera components are connected to a wiring slot in common, and the wiring slot has a built-in camera power line and a communication adapter line.

[0011] In the above solution, the camera assembly has a resolution of at least 8 megapixels. The mounting housing primarily houses the camera assembly and, when the blank temperature is high, protects the camera assembly. Because several camera assembly groups are connected to a common wiring slot via connecting cables, each time the mold assembly is replaced, it is only necessary to connect the camera power cables and communication adapter cables in the wiring slot to the power and communication interfaces of the main control unit. Furthermore, to facilitate and quickly replace mold assemblies while ensuring the camera assembly's installation accuracy and field of view consistency, the mounting housing and camera assembly can be directly secured to the mold cavity, with the connecting cables on the mounting housing secured directly to the wiring slot. This allows simultaneous replacement of the camera module with the mold.

[0012] Furthermore, the positioning pin is made of a transparent material, is hollow inside, and an LED light source is provided in the hollow part.

[0013] In the above solution, the positioning pin made of transparent material facilitates recognition by the camera module; the positioning pin is hollow inside, and the size of the hollow area is suitable for placing an LED directional light source, which is used for visual recognition and analysis.

[0014] Furthermore, the mounting shell includes an inner shell layer and an outer shell layer, the inner shell layer is connected to dry circulating cold air, and the outer shell layer is connected to circulating cooling water.

[0015] In the above scheme, since the blank transferred to the mold has a certain temperature, the mold is usually connected to circulating cooling water for cooling and insulation; based on this, in order to minimize the impact of high temperature on the performance and use of camera components, the mounting shell is designed as an inner and outer two-layer structure, circulating cooling water is introduced into the outer space, and dry circulating cold air is connected to the inner space, so that the inner and outer layers can take away heat at the same time to meet the high-temperature use environment.

[0016] Furthermore, a hydrophobic agent is applied on the inner and outer surfaces of the shell inner layer and the shell outer layer.

[0017] In the above solution, by applying a hydrophobic agent, the waterproofness and hydrophobicity of the inner and outer surfaces of the shell can be improved, making it less likely to be blocked by fog, thereby ensuring the clarity of the image taken by the camera.

[0018] A positioning detection method for a mold device capable of realizing positioning detection of a thermoforming blank is applied to the mold device described above, comprising the following steps:

[0019] S1: Preparation; generate regions of interest and store several process recipes;

[0020] S2: Image acquisition; after taking multiple images, image merging is performed;

[0021] S3: Image processing; segmenting the positioning pin area and the positioning hole area, and extracting the positioning pin edge and the positioning hole edge;

[0022] S4: Positioning situation judgment: judge whether the positioning pin enters the positioning hole;

[0023] S5: According to the judgment result of S4, the hydraulic press is linked to perform punching or the alarm is sounded.

[0024] In the above scheme, step S1 needs to be completed before the mold device is officially activated. Its function is to enable the visual software on the main control computer to store the different regions of interest corresponding to various molds in advance, so that the visual software can quickly match the corresponding regions of interest when the mold is replaced; in step S2, after obtaining multiple images, the images are merged according to the texture overlap of the objects in the field of view to form an overall image, which can reflect the shooting field of all cores and ensure the integrity and comprehensiveness of visual recognition; in step S3, since the positioning pin contains a light source, the image processing algorithm can be used to segment the bright area and the dark area in the image. The bright area is the positioning pin area, and the inner circle of the dark area is the positioning hole area. On this basis, image processing is continued to extract the positioning pin edge and the positioning hole edge; in steps S4 and S5, if all the positioning pins are inserted into the corresponding positioning holes, it means that the transfer of the blank meets the stamping requirements, and the main control computer then links the hydraulic press to perform stamping normally. Otherwise, the main control computer links the alarm to issue an alarm prompt.

[0025] Furthermore, in S1, for different regions of interest corresponding to different molds, each region of interest is matched with a number to generate a process recipe. There are several process recipes in total.

[0026] In the above scheme, since the positions of the positioning pins and camera modules on each set of molds are fixed, and the relative distance between the upper mold and the lower mold is also fixed when the camera is shooting, the areas of interest corresponding to the positioning pins under different molds can be drawn in advance, thereby facilitating recognition by the visual software; on this basis, in order to minimize the matching workload of the visual software as much as possible, a number is defined in advance for the corresponding areas of interest of each set of molds, that is, a process recipe is formed; so that when the mold is replaced, the visual software can directly switch the process recipe without matching specific content.

[0027] Furthermore, in S2, the relevant parameters of the image formed after the image merging are stored in the corresponding process recipe.

[0028] In the above scheme, by storing the relevant parameters of the overall image formed by merging into the corresponding process recipe, the image data in the recipe can be continuously learned and improved, which helps to improve the accuracy of ROI recognition.

[0029] Furthermore, in the step S4 , the roundness and area of ​​the positioning pin region are calculated to determine whether the positioning pin has entered the positioning hole.

[0030] In the above scheme, after the positioning pin passes through the positioning hole, the bright area, that is, the positioning pin area, will occupy the main part of the region of interest; therefore, by calculating the roundness and area of ​​the bright area, the actual positional relationship between the positioning pin and the positioning hole can be determined, where the thresholds of the roundness and area need to be adjusted and matched according to the specific situation.

[0031] Furthermore, after the execution of S5 is completed, the overall posture of the blank is obtained and the relevant data of the posture is stored.

[0032] In the above scheme, the local posture of the blank near each positioning pin is first calculated through the image processing algorithm, and then the local postures are merged to calculate the overall posture of the blank; the relevant data is stored together with other detection data, which can be used as a reference and help improve the stability of the robotic claw in placing the blank.

[0033] The beneficial effects achieved by the present invention are:

[0034] In the present invention, the structure of the traditional mold is redesigned, a positioning pin with a built-in light source is provided on it, and a camera module linked to the hydraulic press and the alarm is added, thereby forming a mold device that integrates positioning and visual inspection functions. Based on this, the conditions for detecting whether the hot blank is placed in place become unique, thereby facilitating the implementation of visual inspection work and making the solution for positioning inspection of the blank truly implemented.

[0035] Compared to traditional molds with limited correction capabilities, the multiple positioning pins on the lower mold can fully position the blank entering the mold. Compared to existing manual monitoring methods, the camera module can automatically visually inspect the placement of the blank and automatically initiate stamping or alarm based on the inspection results. Therefore, this application ensures the efficiency and accuracy of inspection, eliminates the corresponding labor costs, ensures the safety of operators, and ultimately guarantees the safety of the mold and the normal operation of the hot stamping forming production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 is a schematic structural diagram of the mold device according to embodiment 1 of the present invention;

[0037] Figure 2 2 is a flow chart of the positioning detection method according to embodiment 2 of the present invention;

[0038] In the figure: 1. Wiring slot; 2. Upper mold; 3. Cavity; 4. Mounting shell; 5. Lower mold; 6. Positioning pin; 7. Core; 8. Cavity. DETAILED DESCRIPTION

[0039] To clearly illustrate the solution of the present invention, the following is further described with reference to the accompanying drawings:

[0040] Example 1:

[0041] Please refer to Figure 1, a mold device that can realize the positioning detection of hot-formed blanks, including a mold, circulating cooling water is introduced into the mold (a conventional technical means in this field, not shown in the figure), the mold includes an upper mold 2 and a lower mold 5, four cores 7 are evenly arranged on the upper surface of the lower mold 5, and four cavities 8 are correspondingly opened on the upper surface of the upper mold 2; each core 7 is provided with a positioning pin 6 at both ends, the positioning pin 6 is a special transparent material of Pam, the positioning pin 6 is connected to the circulating cooling water in the mold, and a hollow area is also provided inside the positioning pin 6, and a small LED bulb is provided in the area; in the mold cavity 3 of the upper mold 2, a camera module is provided on the inner side of each of the two outermost cavities 8, the camera module includes a mounting shell 4 fixedly connected to the upper mold 2, and a camera assembly is provided in the mounting shell 4, and the camera assemblies of the two camera modules are respectively connected to the same wiring slot 1 through a connecting line; the camera module is linked to the hydraulic press and the alarm through the main control machine. Among them, the mounting shell 4 is made of stainless steel and the shooting window is tempered glass. The mounting shell 4 includes an inner shell layer and an outer shell layer. The inner shell layer is connected to the dry circulating cold air and the outer shell layer is connected to the circulating cooling water. The inner and outer surfaces of the inner shell layer and the outer shell layer are coated with a hydrophobic agent; the resolution of the camera in the camera assembly is 10 million pixels.

[0042] For the above-mentioned mold device, the positioning pin 6 can locate the blank (a positioning hole is reserved in the blank in advance) entering the mold and act as an identification light source. The camera module can automatically perform visual inspection on the placement effect of the blank, and automatically perform stamping or alarm according to the inspection results. Among them, the optical transparency of the special transparent material of Pam is high, and it has ultra-high toughness, excellent physical properties and machining properties, and is resistant to high temperature and high pressure, anti-smashing and anti-collision, so it fully meets the material requirements of this working condition; the positioning pin 6 is connected to the circulating cooling water, which can insulate the LED light bulb and cool the blank; the two camera components are connected to the same wiring slot 1, so that each time the mold device is replaced, it is only necessary to connect the camera power cord and the communication adapter cable in the wiring slot 1 to the power supply and communication interface of the main control machine; the installation shell 4 is directly fixed to the upper mold 2 of the mold, which can It ensures the installation accuracy and consistency of the field of view of the camera components in different molds, and helps to replace the mold device conveniently and quickly, that is, to replace the camera module at the same time as the mold; in order to minimize the impact of high temperature on the performance and use of the camera component, the installation shell 4 is designed to be an inner and outer two-layer structure, and circulating cooling water is introduced into the outer space, and dry circulating cold air is connected to the inner space, so that the inner and outer layers can take away heat at the same time to meet the high-temperature use environment, and by applying a hydrophobic agent, the waterproofness and hydrophobicity of the inner and outer surfaces of the shell can be improved, thereby ensuring the clarity of the image taken by the camera.

[0043] Example 2:

[0044] Please refer to Figure 2A positioning detection method for a mold device capable of detecting the positioning of a thermoforming blank is applied to the mold device described in Example 1, comprising the following steps:

[0045] S1: Preparation. Draw the regions of interest corresponding to the positioning pins 6 under different molds in advance, and define a number for the corresponding regions of interest of each mold, form a process recipe, and store the process recipe;

[0046] S2: Image acquisition. After capturing multiple images, the images are merged based on the texture overlap of the objects in the field of view to form an overall image that reflects the field of view of the entire core 7. The relevant parameters of the image are stored in the corresponding process recipe;

[0047] S3: Image processing. Due to varying lighting conditions in different environments, the image after ROI extraction is first filtered with a mean of 30×30. A dynamic threshold segmentation algorithm is then used to segment the image into bright and dark areas. These areas are then filled in separately: the bright area represents the locating pin 6 area, and the inner circle of the dark area represents the locating hole area. Erosion and dilation operations are then performed on the bright area, and the image containing the difference between the two areas is extracted for edge extraction and fitting. The fitted edge represents the edge of the locating pin 6. The same operation is performed on the dark area to fit the edge of the locating hole.

[0048] S4: Positioning status judgment. The roundness and area of ​​the positioning pin 6 area are calculated. When the roundness is greater than 0.75 and the area is greater than 400 pixels, it means that the positioning pin 6 has entered the positioning hole. When it is identified that all positioning pins 6 are inserted into the corresponding positioning holes, it can be determined that the blank placement meets the stamping requirements, and vice versa.

[0049] S5: Based on the judgment result of S4, if the blank placement meets the stamping requirements, the main control machine will then activate the hydraulic press to perform stamping normally. Otherwise, the main control machine will activate the alarm to issue an alarm. During this process, the area around the positioning pins 6 and the positioning holes is merged to obtain the minimum circumscribed ellipse outline; this ellipse can be understood as a perspective projection of a circle. Based on this projection relationship, the local blank posture near each positioning pin 6 can be calculated. Then, by merging these local postures, the overall blank posture can be calculated, and the data related to the overall posture is stored along with other detection data.

[0050] For the above steps, S1 needs to be completed before the mold device is officially put into use. Its function is to enable the visual software on the main control computer to store the different regions of interest corresponding to various molds in advance, so that when the mold is replaced, the visual software can quickly match the corresponding regions of interest; on this basis, in order to reduce the matching workload of the visual software as much as possible, the corresponding regions of interest of each set of molds are defined with a number in advance, that is, a process recipe is formed, so that when the mold is replaced, the visual software can directly switch the process recipe without matching specific content. In S2, after obtaining multiple images, the images are merged according to the texture overlap of the objects in the field of view to form an overall image. This image can reflect the field of view of all cores 7 and ensure the integrity and comprehensiveness of visual recognition; by storing the relevant parameters of the overall image in the corresponding process recipe, the image data in the recipe can be continuously learned and improved, which helps to improve the accuracy of region of interest recognition. In S5, the relevant data of the overall posture are stored together with other detection data, which can be used as a reference and help to improve the stability of the mechanical claw in placing the blank.

[0051] In summary, the present embodiment 1 and embodiment 2 jointly provide a mold device and a positioning detection method thereof that can realize positioning detection of thermoforming blanks. Compared with the traditional mold with limited correction capability and manual monitoring method:

[0052] This application redesigns the traditional mold to make the conditions for detecting whether the hot blank is placed in place unique, thereby facilitating the implementation of visual inspection work, greatly improving the accuracy and robustness of inspection, and truly implementing the solution for positioning inspection of the blank.

[0053] The camera module automatically performs visual inspection on the blank placement effect and automatically implements stamping or alarm based on the detection results. It can promptly detect incorrect blank placement and stop the hydraulic press stamping action, thereby effectively reducing the loss of thermoforming molds, extending the service life of the molds, and further reducing maintenance and production costs, improving work efficiency and economic benefits.

[0054] Through the automation of mold devices, the labor intensity of workers is reduced and the operational risks are lowered, thereby reducing the company's labor costs and improving production efficiency, which will in turn help significantly improve the technological level of multiple industries.

[0055] Of course, the above contents are only preferred embodiments of the present invention and should not be considered as limiting the scope of the embodiments of the present invention. The present invention is not limited to the above examples. Equivalent changes and improvements made by ordinary technicians in this technical field within the essential scope of the present invention should all fall within the scope of the patent of the present invention.

Claims

1. A mold device capable of realizing positioning detection of thermoforming blanks, characterized in that: The mold comprises an upper mold (2) and a lower mold (5), the lower mold (5) is provided with a plurality of positioning pins (6) with built-in light sources, a plurality of camera modules are provided in the mold cavity (3) of the upper mold (2), and the camera modules are linked with the hydraulic press and the alarm through the main control machine; The positioning needle (6) is made of a transparent material, and the interior of the positioning needle (6) is hollow, and an LED light source is provided in the hollow part; The camera module comprises a plurality of mounting shells (4), each mounting shell (4) being provided with a group of camera components, the mounting shell (4) comprising an inner shell layer and an outer shell layer, the inner shell layer being connected to dry circulating cold air, and the outer shell layer being connected to circulating cooling water.

2. The mold device capable of realizing positioning detection of thermoforming blanks according to claim 1, characterized in that: Several groups of camera components are connected to a wiring slot (1) in common, and the wiring slot (1) has built-in camera power lines and communication adapter lines.

3. The mold device capable of realizing positioning detection of thermoforming blanks according to claim 1, characterized in that: The inner and outer surfaces of the shell inner layer and the shell outer layer are both coated with a hydrophobic agent.

4. A positioning detection method for a mold device capable of realizing positioning detection of a thermoforming blank, applied to the mold device according to any one of claims 1 to 3, characterized in that: The steps include: S1: Preparation; generate regions of interest and store several process recipes; S2: Image acquisition; after taking multiple images, image merging is performed; S3: Image processing; segmenting the positioning pin (6) area and the positioning hole area, and extracting the positioning pin (6) edge and the positioning hole edge; S4: Positioning situation judgment: judging whether the positioning needle (6) enters the positioning hole; S5: According to the judgment result of S4, the hydraulic press is linked to perform punching or the alarm is sounded.

5. The positioning detection method for a mold device capable of realizing positioning detection of a thermoforming blank according to claim 4, characterized in that: In S1, for different regions of interest corresponding to different molds, each region of interest is matched with a number to generate a process recipe. There are several process recipes in total.

6. The positioning detection method for a mold device capable of realizing positioning detection of a thermoforming blank according to claim 4, characterized in that: In S2, the relevant parameters of the image formed after the image merging are stored in the corresponding process recipe.

7. The positioning detection method for a mold device capable of realizing positioning detection of a thermoforming blank according to claim 4, characterized in that: In said S4, the roundness and area of ​​the positioning needle (6) region are calculated to determine whether the positioning needle (6) has entered the positioning hole.

8. The positioning detection method for a mold device capable of realizing positioning detection of a thermoforming blank according to claim 4, characterized in that: After the execution of S5 is completed, the overall posture of the blank is obtained and the relevant data of the posture is stored.

Images