A method for welding and enlarging the nozzle of a precious metal sprue plate.

Abstract

This invention relates to a method for welding and expanding the hole of a precious metal sprue nozzle, specifically a method for welding and expanding the hole of a precious metal sprue nozzle. By setting up a welding calibration unit for obtaining optimal welding parameters and a hole-expanding calibration unit for obtaining optimal hole-expanding parameters, the optimal welding parameters and optimal hole-expanding parameters obtained in advance through calibration experiments are used to control a welding Cartesian coordinate robot and a hole-expanding Cartesian coordinate robot to weld and expand the hole of the nozzle, respectively. This method ensures the quality of nozzle welding and hole expansion while taking into account the production efficiency of the product.

Description

Technical Field

[0001] This invention relates to the field of precious metal product processing, specifically to a method for welding and expanding the nozzle of a precious metal stencil. Background Technology

[0002] Precious metal spinnerets are one of the key devices in glass fiber manufacturing. Their overall structure, especially the design and forming quality of the drawing nozzle, directly affects the quality of glass fiber and production costs.

[0003] Previously, the welding and reaming of precious metal sprue plates and nozzles were all done manually. As is well known, relying on manual methods for welding and reaming sprue plates and nozzles is not only inefficient but also compromises product quality. To avoid the many drawbacks of manual production, automation is currently commonly used for welding and reaming sprue plates and nozzles. However, because these technologies are not yet mature and lack practicality, many problems still exist:

[0004] For example, in the hole-expanding process, the patent application CN217253029U, titled "An Automatic Hole-Expanding Device for Leaking Nozzles," uses a method of combining regional photographs of the squeegee plate to determine the final position of the leaking nozzle when drawing the actual position diagram. Multiple photographs of the overlapping areas of the leaking nozzle are taken, and the average of the two images is used. While this method only requires two samples, resulting in relatively high production efficiency, it is unrealistic to accurately determine the final position of the leaking nozzle based solely on the average of two samples. This means that this hole-expanding method has a large error margin, poor hole-expanding quality, and the possibility of the final position of the leaking nozzle deviating from its actual position still exists, affecting product quality and limiting its practicality.

[0005] For example, in welding, the automatic welding equipment and manufacturing process for platinum wire drawing stencils disclosed in CN112388112A uses a dual-axis drive for the X and Y axes, but lacks a Z-axis drive. During assembling the stencil, excessive assembly pressure can cause slight deformation. Since this equipment lacks a Z-axis drive, the welding head is fixed in the Z-axis direction, making it impossible to adjust the Z-axis position in real time to correct deviations in the welding point. Using this equipment for welding stencil nozzles easily leads to incomplete welding, affecting product quality and limiting its practicality.

[0006] Furthermore, the patent application CN112388112A, titled "An Automatic Welding Equipment for Platinum Wire Drawing Spinnerets and a Manufacturing Process for Platinum Wire Drawing Spinnerets," requires the calibration of a pre-set drawing with a photographed image during the spinneret welding process. The welding torch position is determined by judging the standard reference points on the pre-set drawing and the real-time position of the center of the spinneret to be welded. While this method can significantly improve the welding quality of the spinneret, it neglects the efficiency issues in actual operation. If the standard reference points on the pre-set drawing do not coincide with the real-time position of the spinneret center, the equipment will be unable to automatically proceed to the next step. In this case, only after the operator recalibrates the pre-set drawing and restarts the equipment can production continue, which is time-consuming, labor-intensive, and has extremely low practicality.

[0007] In summary, current automated welding and hole-expanding processes for perforated plates either blindly prioritize increasing production efficiency while neglecting product quality (i.e., hole-expanding quality and welding quality), or they focus excessively on ensuring product quality while ignoring the importance of production efficiency. Finding a balance between production efficiency and product quality remains a pressing issue for those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for welding and expanding the nozzle of a precious metal sprue. This method involves setting up a welding calibration unit for obtaining optimal welding parameters and a expanding calibration unit for obtaining optimal expanding parameters. By using the optimal welding parameters and optimal expanding parameters obtained through pre-calibration experiments, a welding Cartesian coordinate robot and a expanding Cartesian coordinate robot are respectively controlled to weld and expand the nozzle. This method ensures the quality of nozzle welding and expanding while maintaining production efficiency.

[0009] The objective of this invention is achieved through the following approach:

[0010] A method for welding and expanding the nozzle of a precious metal sprue plate includes the following steps:

[0011] 1) Set up a welding calibration unit in the intelligent control system of the automatic welding device to obtain the optimal welding parameters, and set up a hole reaming calibration unit in the intelligent control system of the automatic hole reaming device to obtain the optimal hole reaming parameters.

[0012] 2) Determine the optimal welding scheme for the leak nozzle through welding calibration experiments;

[0013] 3) Determine the optimal reaming scheme for the leak nozzle through reaming calibration experiments;

[0014] 4) Based on the optimal welding parameters in the optimal welding scheme, the nozzles on the precious metal stencil are welded sequentially under the control of the welding PLC controller of the automatic welding device;

[0015] 5) Based on the optimal hole-expansion parameters of the optimal hole-expansion scheme, the holes on the precious metal sprue are expanded sequentially under the control of the hole-expansion PLC controller of the automatic hole-expansion device.

[0016] Preferably, in step 2), the optimal welding scheme for the leak nozzle is determined through a welding calibration experiment, including the following steps:

[0017] 2-1) Based on the geometric parameters of the stencil and nozzle to be welded, determine the range of welding parameters according to empirical values;

[0018] 2-2) Arrange and combine the values ​​of the welding parameters within the range to form several trial welding schemes;

[0019] 2-3) Under the control of the welding PLC controller, the nozzles assembled on the precious metal stencil are automatically welded according to the several trial welding schemes obtained in step 2-2), and the acceptance data of each trial welding scheme are recorded and stored in the welding calibration unit.

[0020] 2-4) Select the best welding test plan from several welding acceptance data as the best welding plan for the slot plate and nozzle, and use the automatic welding device to perform automatic welding according to the best welding plan.

[0021] Preferably, in step 3), the optimal reaming scheme for the leak nozzle is determined through a reaming calibration experiment, including the following steps:

[0022] 3-1) Determine the range of values ​​for the enlargement parameters based on the geometric parameters of the squeegee and nozzle to be enlarged, according to empirical values.

[0023] 3-2) Arrange and combine the values ​​of the hole enlargement parameters within the range to form several trial hole enlargement schemes;

[0024] 3-3) Under the control of the hole expansion PLC controller, the nozzles welded to the precious metal stencil are automatically expanded according to the several trial hole expansion schemes obtained in step 3-2), and the acceptance data of each trial hole expansion scheme is recorded and stored in the hole expansion calibration unit.

[0025] 3-4) Select the best hole-expansion scheme from several hole-expansion acceptance data as the best hole-expansion scheme for the squeegee and nozzle, and use the automatic hole-expansion device to automatically expand the hole according to the best hole-expansion scheme.

[0026] Preferably, the geometric parameters of the squeegee include the number of holes in the squeegee, the diameter of the holes in the squeegee, and the thickness of the squeegee, and the geometric parameters of the nozzle include the outer diameter of the nozzle, the inner diameter of the nozzle, and the height of the nozzle.

[0027] Preferably, the welding parameters include welding scanning speed, welding direction, inter-hole welding connection method, welding current, welding current judgment threshold, welding speed, welding diameter, arc extinguishing delay time, and initial distance between the bottom of the welding torch and the upper surface of the slot plate.

[0028] Preferably, the hole enlargement parameters include hole enlargement scanning speed, hole enlargement robot moving speed, drill bit rotation speed, drill bit descent speed, drill bit diameter, and initial distance between the bottom of the drill bit and the upper surface of the sprue plate.

[0029] Preferably, in step 4), the nozzles on the precious metal stencil are sequentially welded under the control of the welding PLC controller of the automatic welding device, including:

[0030] 4-1) Turn on the power of the automatic welding device, initialize the status of the automatic welding device, and return the position of the welding Cartesian coordinate robot to the origin;

[0031] 4-2) Select the optimal welding parameters according to the model of the stencil and nozzle through the human-machine interface of the automatic welding device;

[0032] 4-3) Clamp the precious metal stencil to be welded onto the worktable of the automatic welding device;

[0033] 4-4) Start the automatic welding device to weld all the nozzles to be welded onto the weld plate.

[0034] Preferably, in step 5), the nozzles on the precious metal reamer are sequentially reamed under the control of the reaming PLC controller of the automatic reaming device, including:

[0035] 5-1) Turn on the power of the automatic hole reaming device, initialize the status of the automatic hole reaming device, and return the position of the hole reaming Cartesian coordinate robot to the origin;

[0036] 5-2) Select the optimal reaming parameters according to the model of the stencil and nozzle by operating the human-machine interface of the automatic reaming device;

[0037] 5-3) Clamp the precious metal sprue plate with the sprue nozzle welded onto the worktable of the automatic hole enlarging device;

[0038] 5-4) Start the automatic hole enlarging device to enlarge the inner hole of the nozzle welded to the precious metal squeegee plate.

[0039] Preferably, in step 4), when the automatic welding device welds all the nozzles to be welded onto the precious metal plate, it includes the following two modes:

[0040] Overall scanning welding mode:

[0041] (1) Select the number of groups or individual nozzles to be welded through the human-machine interface;

[0042] (2) The automatic welding device scans and stores all the locations of the nozzles to be welded selected in step (1), and then performs welding on the nozzles.

[0043] Local scanning welding mode:

[0044] (1) The automatic welding device obtains the position of a nozzle on the stencil by scanning, and then welds the nozzle according to the position of the nozzle;

[0045] (2) Repeat step (1) until all the nozzles on the sprue plate are welded.

[0046] The beneficial effects of this invention are as follows:

[0047] 1) Set up a welding calibration unit in the intelligent control system of the automatic welding device to obtain the optimal welding parameters, and set up a hole reaming calibration unit in the intelligent control system of the automatic hole reaming device to obtain the optimal hole reaming parameters.

[0048] 2) Determine the optimal welding scheme for the leak nozzle through welding calibration experiments;

[0049] 3) Determine the optimal reaming scheme for the leak nozzle through reaming calibration experiments;

[0050] 4) Based on the optimal welding parameters in the optimal welding scheme, the nozzles on the precious metal stencil are welded sequentially under the control of the welding PLC controller of the automatic welding device;

[0051] 5) Based on the optimal hole-expansion parameters of the optimal hole-expansion scheme, the holes on the precious metal sprue are expanded sequentially under the control of the hole-expansion PLC controller of the automatic hole-expansion device.

[0052] This invention provides a welding calibration unit for obtaining optimal welding parameters and a hole-expanding calibration unit for obtaining optimal hole-expanding parameters. By using the optimal welding parameters and optimal hole-expanding parameters obtained in advance through calibration experiments, the automatic welding device and the automatic hole-expanding device are respectively controlled to perform nozzle welding and hole expansion. While improving the welding speed and hole-expanding speed, the quality of welding and hole expansion is greatly improved.

[0053] Preferably, the welding parameters include welding scanning speed, welding direction, inter-hole welding connection method, welding current, welding current judgment threshold, welding speed, welding diameter, arc extinguishing delay time, and initial distance between the bottom of the welding torch and the upper surface of the slot plate.

[0054] Preferably, the hole enlargement parameters include hole enlargement scanning speed, hole enlargement robot moving speed, drill bit rotation speed, drill bit descent speed, drill bit diameter, and initial distance between the bottom of the drill bit and the upper surface of the sprue plate.

[0055] This invention identifies various parameter types that affect the welding and hole-expanding quality of the nozzle during welding and hole-expanding processes through experiments. It also determines specific values ​​for different nozzles and nozzle plates through calibration experiments, which serve as guiding data for welding and hole-expanding processes, thereby greatly improving the quality of welding and hole-expanding.

[0056] Preferably, the geometric parameters of the squeegee include the number of holes in the squeegee, the diameter of the holes in the squeegee, and the thickness of the squeegee, and the geometric parameters of the nozzle include the outer diameter of the nozzle, the inner diameter of the nozzle, and the height of the nozzle.

[0057] Typically, the geometric parameters of the stencil and nozzles are provided by the manufacturer (e.g., drawings). However, in practice, some geometric parameters of the stencil can also be obtained by scanning the stencil on an automated welding machine. These parameters include the number of holes in the stencil, the hole diameter, the outer diameter and inner diameter of the nozzles, and the actual distribution of each nozzle on the stencil. This ensures that the parameter values ​​obtained in subsequent calibration experiments are more consistent with actual conditions, thus improving calibration accuracy.

[0058] Preferably, in step 4), when the automatic welding device welds all the nozzles to be welded onto the precious metal plate, it includes the following two modes:

[0059] Overall scanning welding mode:

[0060] (1) Select the number of groups or individual nozzles to be welded through the human-machine interface;

[0061] (2) The automatic welding device scans and stores all the locations of the nozzles to be welded selected in step (1), and then performs welding on the nozzles.

[0062] The overall scanning welding mode performs a comprehensive scan of all nozzles on the entire precious metal stencil. This method obtains complete welding layout information, ensuring that welding parameters remain relatively consistent throughout the welding area. This results in more uniform and stable welding quality for each nozzle, reducing quality fluctuations caused by differences in welding parameters and improving the overall quality and performance of the stencil.

[0063] In actual welding processes, there is no need to frequently adjust equipment parameters to adapt to the welding requirements of different nozzles. For example, if dozens of nozzles of the same specification need to be welded onto a welding plate, after scanning and confirming that their material, size, and other parameters are the same, welding can be performed using uniform welding current, voltage, and speed parameters. This reduces the time spent adjusting parameters for each nozzle and greatly improves the overall welding efficiency. Furthermore, it is easy to integrate with automated production lines, enabling automatic identification of welding plate shape, nozzle positioning, and automatic welding path planning. This reduces manual intervention, lowers labor intensity and the impact of human factors on welding quality, and improves the automation level and stability of production.

[0064] Local scanning welding mode:

[0065] (1) The automatic welding device obtains the position of a nozzle on the stencil by scanning, and then welds the nozzle according to the position of the nozzle;

[0066] (2) Repeat step (1) until all the nozzles on the sprue plate are welded.

[0067] Local scanning welding mode scans only one nozzle and its corresponding welding position at a time. This method allows for precise scanning and welding of each nozzle or specific local area, better adapting to individual differences and special requirements of nozzles. For example, for individual nozzles with positional deviations or dimensional abnormalities, precise welding can be performed separately, improving the targeting and adaptability of the welding process. During the welding process, if a nozzle or local area requires special handling, such as adjusting welding parameters or performing repair welding, the operation can be carried out more flexibly without affecting the welding progress of the entire stencil or the welding quality of other nozzles, facilitating the timely resolution of individual problems that arise during the welding process.

[0068] The advantages of this invention are as follows:

[0069] ① This invention sets up a welding calibration unit for storing optimal welding parameters and a hole-expanding calibration unit for storing optimal hole-expanding parameters. It uses the optimal welding parameters and optimal hole-expanding parameters obtained in advance through calibration experiments, and controls the welding Cartesian coordinate robot and the hole-expanding Cartesian coordinate robot to perform nozzle welding and hole expansion, respectively. While improving the welding speed and hole expansion speed, it greatly improves the quality of welding and hole expansion.

[0070] ② The welding rectangular coordinate robot of the automatic welding device used in this invention is equipped with a Z-axis guide rail, which enables the intelligent control system to control the welding torch to move in the vertical direction. This effectively avoids the technical defects existing in the "Automatic Welding Equipment for Platinum Wire Drawing Spinner and Manufacturing Process of Platinum Wire Drawing Spinner" with publication number CN112388112A, and effectively improves the welding quality of the nozzle.

[0071] The automatic welding device used in this invention, when positioning the nozzle, uses an intelligent control system that combines the distribution diagram of the nozzles on the nozzle plate to control the movement of the welding rectangular coordinate robot, so that the welding vision recognition device can scan the nozzles one by one and directly obtain the coordinate position of the nozzle, thereby realizing the positioning of the nozzle. This effectively avoids the technical defects of the "Automatic Welding Equipment for Platinum Wire Drawing Spinner and Manufacturing Process of Platinum Wire Drawing Spinner" with publication number CN112388112A, and greatly improves the efficiency of nozzle welding.

[0072] ③ The automatic hole-expanding device used in this invention, when positioning the leak nozzle, uses an intelligent control system that combines the distribution diagram of the leak nozzles on the leak plate to control the movement of the hole-expanding rectangular coordinate robot, so that the hole-expanding visual recognition device scans the leak nozzles one by one and directly obtains the coordinate position of the leak nozzle, thereby realizing the positioning of the leak nozzle. This effectively avoids the technical defects of the "Automatic Hole-Expanding Device for Leak Nozzles" published in CN217253029U, and greatly improves the quality of hole expansion.

[0073] Glossary

[0074] Arc extinction delay time: In this invention, it refers to the time interval from the issuance of the arc extinction command (e.g., the control signal to cut off the circuit) to the actual complete extinction of the arc during the arc extinction process;

[0075] Scanning speed: This refers to the time required for the visual recognition device to identify a hole on the stencil. The value of "scanning speed" in this invention actually includes the time it takes for the visual recognition device to move from the previous hole to the hole to be identified and complete the identification of the center position of the current hole, as well as the time it takes for the visual recognition device to move from the current hole to the next hole.

[0076] Welding speed: This refers to the time required to weld a nozzle onto a precious metal stencil. The value of "welding speed" in this invention actually includes the time taken for the reaming device to move from the upper nozzle position to the nozzle to be welded position and complete the welding of the current nozzle during the welding process, as well as the time taken for the reaming device to move from the current nozzle position to the next nozzle position.

[0077] Precious metal leak plate after leak nozzle assembly: In this invention, it refers to a precious metal leak plate in which leak nozzles have been assembled and installed in each leak nozzle assembly hole, but welding and hole enlargement have not yet been performed. Attached Figure Description

[0078] Figure 1 This is a schematic diagram of the automatic welding device described in this invention;

[0079] Figure 2 This is a schematic diagram of the automatic hole-expanding device described in this invention;

[0080] Figure 3 for Figure 1 Enlarged view of point A;

[0081] Figure 4 for Figure 2 Enlarged view of point B;

[0082] Figure 5 This is a schematic diagram showing the distribution of the precious metal nozzle on the leak plate in this invention;

[0083] Figure 6 The welding procedure logic diagram of this invention;

[0084] Figure 7 The hole-expanding procedure logic diagram of the present invention. Detailed Implementation

[0085] like Figures 1 to 7 As shown, a method for welding and expanding the nozzle of a precious metal sprue includes the following steps:

[0086] 1) Set up a welding calibration unit in the intelligent control system of the automatic welding device to obtain the optimal welding parameters, and set up a hole reaming calibration unit in the intelligent control system of the automatic hole reaming device to obtain the optimal hole reaming parameters.

[0087] 2) Determine the optimal welding scheme for the leak nozzle through welding calibration experiments using the following methods:

[0088] 2-1) Based on the geometric parameters of the stencil and nozzle to be welded, determine the range of welding parameters according to empirical values;

[0089] The geometric parameters of the squeegee include the number of holes in the squeegee, the diameter of the holes in the squeegee, and the thickness of the squeegee. The geometric parameters of the nozzle include the outer diameter of the nozzle, the inner diameter of the nozzle, and the height of the nozzle.

[0090] The welding parameters include welding scanning speed, welding direction, inter-hole welding connection method, welding current, welding current judgment threshold, welding speed, welding diameter, arc extinguishing delay time, and initial distance between the bottom of the welding torch and the upper surface of the slot plate.

[0091] 2-2) Arrange and combine the values ​​of the welding parameters within the range to form several trial welding schemes;

[0092] In practical applications, the test step size for each welding parameter can be set according to quality requirements. This allows for the determination of welding parameter values ​​before permutations and combinations. For example, the welding parameters and their corresponding test step sizes are as follows:

[0093] 2-2-1) Welding scanning speed 200-400 ms / hole, the test step size of welding scanning speed can be set to 100 ms / hole;

[0094] For example, the data involved in the permutation and combination are 200, 300, and 400 ms / hole.

[0095] 2-2-2) Welding directions include straight welding and zigzag welding. The inter-hole welding connection methods include non-extinguishing arc welding and extinguishing arc welding, wherein the extinguishing arc delay time is 100-200ms, and the test step of the extinguishing arc delay time can be set to 50ms.

[0096] For example, the data involved in the permutation and combination are 100 ms, 150 ms, and 200 ms.

[0097] 2-2-3) The welding diameter is +0.5 to +0.7 mm of the outer diameter of the nozzle, the welding speed is 200 to 400 ms / hole, and the initial distance between the bottom of the welding torch and the upper surface of the nozzle plate is 0.5 to 1 mm.

[0098] The test step size for welding diameter can be set to 0.1 mm, the test step size for welding speed can be set to 50 ms / hole, and the test step size for the initial distance between the bottom of the welding torch and the upper surface of the sprue plate can be set to 0.1 mm.

[0099] For example, the welding diameter data for the permutation and combination are 0.5 mm, 0.6 mm, and 0.7 mm; the welding speed data for the permutation and combination are 200 ms / hole, 250 ms / hole, 300 ms / hole, 350 ms / hole, and 400 ms / hole; and the initial distance data between the bottom of the welding torch and the upper surface of the stencil for the permutation and combination are 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm.

[0100] 2-2-4) The welding current includes the middle welding current and the outer welding current. The middle welding current is 35-45A and the outer welding current is 40-55A.

[0101] The test step size for the middle welding current can be set to 5A, and the test step size for the outer welding current can be set to 1A. Similarly, several data points for the middle welding current and outer welding current participating in the permutation and combination can be obtained.

[0102] 2-2-5) The welding current judgment threshold is set according to the distribution of the nozzles on the stencil and the required product quality. The test step size of the welding current judgment threshold can be set to 1.

[0103] In this invention, the intelligent control system divides the nozzles into several layers based on the nozzle distribution diagram of the precious metal stencil and the distance between each nozzle and the edge of the stencil. The welding current judgment threshold represents the number of nozzle layers on the stencil from the edge to the center. The actual coordinate position obtained by scanning is compared with the coordinate position of the nozzle distribution diagram of the metal stencil in the intelligent control system to obtain the actual nozzle layer number to which the nozzle belongs. The actual nozzle layer number is then compared with the welding current judgment threshold to determine whether the nozzle belongs to the outer or middle part of the stencil.

[0104] ① If the actual number of nozzle layers is less than or equal to the welding current judgment threshold, the nozzle is determined to be an outer nozzle, and the welding torch is connected to the outer welding current.

[0105] ② If the actual number of leak layers is greater than the welding current judgment threshold, the leak is determined to be a middle leak, and the welding torch is connected to the middle welding current.

[0106] 2-3) Under the control of the welding PLC controller, the nozzles assembled on the precious metal stencil are automatically welded according to the several trial welding schemes obtained in step 2-2), and the acceptance data of each trial welding scheme are recorded and stored in the welding calibration unit.

[0107] 2-4) Select the best welding test plan from several welding acceptance data as the best welding plan for the slot plate and nozzle, and use the automatic welding device to perform automatic welding according to the best welding plan.

[0108] 3) Determine the optimal reaming scheme for the leak nozzle through a reaming calibration experiment using the following method:

[0109] 3-1) Determine the range of values ​​for the enlargement parameters based on the geometric parameters of the squeegee and nozzle to be enlarged, according to empirical values.

[0110] The hole enlargement parameters include hole enlargement scanning speed, hole enlargement robot moving speed, drill bit rotation speed, drill bit descent speed, drill bit diameter, and initial distance between the bottom of the drill bit and the upper surface of the sprue plate.

[0111] 3-2) Arrange and combine the values ​​of the hole enlargement parameters within the range to form several trial hole enlargement schemes;

[0112] In practical applications, the test step size for each hole-expansion parameter can be set according to the quality requirements of the hole-expansion process. This is used to determine the values ​​of the hole-expansion parameters before arranging and combining them. For example, the hole-expansion parameters and their corresponding test step sizes are as follows:

[0113] 3-2-1) The reaming scanning speed is 200-400 ms / hole, and the reaming robot moving speed is 200-400 ms / hole;

[0114] The test step size for the hole reaming scanning speed can be set to 100ms / hole, and the test step size for the hole reaming robot movement speed can be set to 100ms / hole.

[0115] 3-2-2) The drill bit rotation speed is 1000-3000 rpm, and the drill bit descent speed is 1-3 mm / s;

[0116] The test step size for drill bit rotation speed can be set to 1000 rpm, and the test step size for drill bit descent speed and drill bit diameter can be set to 1 mm / s.

[0117] 3-2-3) The initial distance between the bottom of the drill bit and the upper surface of the sprue plate is 0.5 to 1 mm, and the test step of the initial distance between the bottom of the drill bit and the upper surface of the sprue plate can be set to 0.1 mm.

[0118] 3-3) Under the control of the hole expansion PLC controller, the nozzles welded to the precious metal stencil are automatically expanded according to the several trial hole expansion schemes obtained in step 3-2), and the acceptance data of each trial hole expansion scheme is recorded and stored in the hole expansion calibration unit.

[0119] 3-4) Select the best hole-expansion scheme from several hole-expansion acceptance data as the best hole-expansion scheme for the squeegee and nozzle, and use the automatic hole-expansion device to automatically expand the hole according to the best hole-expansion scheme.

[0120] During the welding process of precious metal nozzles, tiny inward protrusions will be generated at the weld seam of the nozzle, with a height range of approximately 0.01mm to 0.02mm. The automatic hole-expanding method of this invention can precisely expand these inwardly protruding parts, thereby ensuring that the inner diameter of the weld joint is consistent with the inner diameter of the nozzle as a whole, so as to meet the corresponding process standards and usage requirements.

[0121] 4) Based on the optimal welding parameters in the optimal welding scheme, weld the nozzles on the precious metal stencil sequentially under the control of the welding PLC controller of the automatic welding device in the following manner:

[0122] 4-1) Turn on the power of the automatic welding device, initialize the status of the automatic welding device, and return the position of the welding Cartesian coordinate robot to the origin;

[0123] 4-2) Select the optimal welding parameters according to the model of the stencil and nozzle through the human-machine interface of the automatic welding device;

[0124] 4-3) Clamp the precious metal stencil to be welded onto the worktable of the automatic welding device;

[0125] 4-4) Start the automatic welding device to weld all the nozzles to be welded onto the weld plate.

[0126] It is worth noting that when welding nozzles on a precious metal stencil sequentially under the control of the welding PLC controller of an automatic welding device, two welding modes are typically included: overall scanning welding mode and partial scanning welding mode. In actual production, different scanning welding modes can be selected according to specific quality requirements, for example:

[0127] Overall scanning welding mode:

[0128] (1) Select the number of groups or individual nozzles to be welded through the human-machine interface;

[0129] (2) The automatic welding device scans and stores all the locations of the nozzles to be welded selected in step (1), and then performs welding on the nozzles, as follows:

[0130] ① The welding vision recognition device moves to the scanning position and scans the nozzles on the nozzle plate according to the scanning sequence (generally sequential scanning, that is, scanning a column of nozzles completely along the Y-axis, then moving one nozzle position along the X-axis, and then scanning in the opposite direction along the Y-axis, repeating this process until all nozzles on the nozzle plate have been scanned). The device obtains the coordinates of the current nozzle and the distance to the next nozzle in sequence and feeds the data back to the intelligent control system.

[0131] ② Based on the data feedback obtained in step ①, the intelligent control system controls the welding torch to move to the position of the nozzle to be welded;

[0132] ③ The welding torch is connected to the corresponding welding current according to the set welding parameters to weld the nozzle on the stencil;

[0133] ④ Repeat steps ② to ③ above to complete the welding of each nozzle on the sprue plate in sequence.

[0134] Local scanning welding mode:

[0135] (1) The automatic welding device obtains the position of a nozzle on the stencil by scanning, and then welds the nozzle according to the position of the nozzle;

[0136] (2) Repeat step (1) until all the nozzles on the sprue plate are welded.

[0137] 5) Based on the optimal reaming parameters of the optimal reaming scheme, the nozzles on the precious metal reaming plate are sequentially reamed under the control of the reaming PLC controller of the automatic reaming device in the following manner:

[0138] 5-1) Turn on the power of the automatic hole reaming device, initialize the status of the automatic hole reaming device, and return the position of the hole reaming Cartesian coordinate robot to the origin;

[0139] 5-2) Select the optimal reaming parameters according to the model of the stencil and nozzle by operating the human-machine interface of the automatic reaming device;

[0140] 5-3) Clamp the precious metal sprue plate with the sprue nozzle welded onto the worktable of the automatic hole enlarging device;

[0141] 5-4) Start the automatic hole enlarging device to enlarge the inner hole of the nozzle welded to the precious metal squeegee plate.

[0142] The invention relates to an automatic welding device and an automatic hole-expanding device for welding and expanding the holes of the aforementioned precious metal sprue, used to improve welding and hole-expanding quality. The automatic welding device includes a welding worktable 1, an expanding worktable 20, a welding Cartesian coordinate robot 5 mounted on the welding worktable 1, and an expanding Cartesian coordinate robot 8 mounted on the expanding worktable 20. It also includes a human-machine interface 18 for issuing commands to the intelligent control system. In this invention, the intelligent control system, by combining the distribution diagram of the sprue nozzles on the sprue and the work paths of manual welding and manual hole-expanding, develops algorithms and programs in a PLC controller suitable for the operation of the automatic welding device and the automatic hole-expanding device. These algorithms and programs enable functions such as sprue nozzle position recognition, sprue nozzle welding actions, and sprue nozzle hole-expanding actions. A simple and fully functional human-machine interface 18 is established to issue commands for welding and expanding the holes of the precious metal sprue and sprue nozzles.

[0143] The Cartesian coordinate robot includes a welding Cartesian coordinate robot 5 and a hole-reaming Cartesian coordinate robot 8. The welding worktable 1 of the automatic welding device is equipped with the welding Cartesian coordinate robot 5 for welding nozzles and a welding fixture 3 for fixing the nozzle plate. The welding fixture 3 includes a nozzle plate fixture for mounting the nozzle plate and a water-cooled plate located below the nozzle plate fixture. The water-cooled plate has internal water-cooling channels. When external cooling water flows through the water-cooled plate, the water flow absorbs heat from the fixture and the nozzle plate and carries it out of the fixture, ensuring that the temperature of the welding fixture 3 and the nozzle plate is relatively stable during the welding process, preventing overheating. The top of the nozzle plate fixture has multiple mounting slots. The position and size of the mounting slots are adapted to the nozzles on the nozzle plate to facilitate fixing the nozzle plate and ensure the parallelism between the surface of the nozzle plate and the worktable.

[0144] The end effector of the welding Cartesian coordinate robot 5 is a welding torch 4 for welding nozzles. The welding torch 4 is electrically connected to a welding machine 2 for generating welding energy. The intelligent control system adjusts the corresponding welding parameters (inter-hole welding connection method, welding current, and arc extinguishing delay time) by controlling the welding machine 2. The connecting cable between the welding torch 4 and the welding machine 2 is fixed by the conduit fixing member 19.

[0145] A welding vision recognition device 6 for identifying the position of each nozzle on the stencil is provided beside the welding torch 4, and a distance sensor 7 for detecting stencil deformation is provided. The distance sensor 7 is electrically connected to the PLC controller. Specifically, the distance sensor 7 is used to detect the deformation of the stencil on the Z-axis and feeds the obtained data back to the PLC controller, which then controls the movement of the welding Cartesian coordinate robot to adjust the height of the welding torch and improve the welding quality of the stencil. The welding vision recognition device 6 and the welding machine 2 are both electrically connected to the welding calibration unit set on the welding worktable 1 of the automatic welding device to acquire and store the optimal welding parameters for the nozzles.

[0146] The automatic reaming device has a reaming worktable 20 equipped with a reaming Cartesian coordinate robot 8 for reaming the nozzles and a reaming fixture 9 for fixing the nozzle plate. The end effector of the reaming Cartesian coordinate robot 8 is a reaming device 10 for reaming the nozzles. A reaming vision recognition device 11 is set next to the reaming device 10. The reaming vision recognition device 11 is used to identify the center position of each nozzle on the nozzle plate. The reaming vision recognition device 10 is electrically connected to the reaming calibration unit set on the reaming worktable 20 of the automatic reaming device, and is used to acquire and store the optimal reaming parameters of the nozzles.

[0147] The welding calibration unit is connected to the welding PLC controller, and the hole enlargement calibration unit is connected to the hole enlargement PLC controller.

[0148] The Cartesian coordinate robot includes an X-axis guide rail 12, a Y-axis guide rail 13, and a Z-axis guide rail 14. Two X-axis guide rails 12 are installed on the welding worktable 1 and the reaming worktable 20. The two ends of the Y-axis guide rail 13 are connected to the first slider 15 on the X-axis guide rail 12. The Z-axis guide rail 14 is connected to the second slider 16 on the Y-axis guide rail 13, and a third slider 16 is installed on the Z-axis guide rail 14. A welding torch 4, a welding vision recognition device 6, and a distance sensor 7 are installed on the third slider 17 of the welding Cartesian coordinate robot 5. A reaming device 10 and a reaming vision recognition device 11 are installed on the third slider 17 of the reaming Cartesian coordinate robot 8. Both the welding vision recognition device 6 and the reaming vision recognition device 11 are high-pixel industrial cameras.

[0149] The X-axis guide rail 12, Y-axis guide rail 13, and Z-axis guide rail 14 all employ linear motors. The precision of these linear motors is 0.5 μm. Specifically, the X-axis guide rail 12, Y-axis guide rail 13, and Z-axis guide rail 14 are magnetic guide rails. By energizing coils inside the first slider 15, second slider 16, and third slider 17, a magnetic field is generated. This magnetic field interacts with the magnetic material within the magnetic guide rail, generating a driving force that propels the sliders to slide on the magnetic guide rail, thereby achieving omnidirectional movement of the end effector. This invention, by employing linear motors as a driving method to control the movement of the welding Cartesian coordinate robot 5 and the hole-reaming Cartesian coordinate robot 8, offers advantages such as quiet operation, smoothness, precision, and strong controllability.

[0150] According to the method for welding and expanding the nozzle of the precious metal sprue according to the present invention, examples 1, 2, and 3 are provided below using an automatic welding device and an automatic expanding device:

[0151] Example 1: A squeegee plate with 400 holes for nozzle mounting is used for welding and hole enlargement. The squeegee plate is 2.0 mm thick, the diameter of the nozzle mounting holes is 2.7 mm, the outer diameter of each nozzle is 2.7 mm, the inner diameter is 1.8 mm, and the height is 6.5 mm.

[0152] Example 2: A leak plate with 800 holes for nozzle mounting is used for welding and hole enlargement. The base plate thickness is 1.8 mm, the base plate hole diameter is 2.6 mm, the outer diameter of the leak nozzle is 2.6 mm, the inner diameter is 1.8 mm, and the height is 6.0 mm.

[0153] Example 3: A leak plate with 1200 holes for nozzle mounting is used for welding and hole enlargement. The base plate thickness is 1.6 mm, the base plate hole diameter is 2.6 mm, the outer diameter of the leak nozzle is 2.6 mm, the inner diameter is 1.7 mm, and the height is 6.5 mm.

[0154] I. The optimal welding parameter ranges for welding the stencils and nozzles of each embodiment using the automatic welding device were determined through calibration experiments as follows:

[0155] (1) The welding scanning speed is 200-400 ms / hole;

[0156] (2) Welding directions include straight welding and zigzag welding. The inter-hole welding connection methods include non-extinguishing arc welding and extinguishing arc welding, wherein the arc extinguishing delay time is 100-200ms.

[0157] (3) The welding diameter is +0.5 to +0.7 mm of the outer diameter of the nozzle, the welding speed is 200 to 400 ms / hole, and the initial distance between the bottom of the welding torch and the upper surface of the nozzle plate is 0.5 to 1 mm.

[0158] (4) The welding current includes the middle welding current and the outer welding current. The middle welding current is 35-45A, and the outer welding current is 40-55A.

[0159] (5) The welding current judgment threshold is set according to the distribution of the nozzles on the stencil and the required product quality.

[0160] II. The optimal range of reaming parameters for reaming the nozzles of each embodiment using the automatic reaming device was determined through calibration experiments as follows:

[0161] (1) The reaming scanning speed is 200-400 ms / hole, and the reaming robot moving speed is 200-400 ms / hole;

[0162] (2) The drill bit rotation speed is 1000-3000 rpm, and the drill bit descent speed is 1-3 mm / s;

[0163] (3) The initial distance between the bottom of the drill bit and the upper surface of the sprue plate is 0.5 to 1 mm, and the test step of the initial distance between the bottom of the drill bit and the upper surface of the sprue plate can be set to 0.1 mm.

[0164] Third, the values ​​of the above welding parameters and hole-expansion parameters within their respective ranges are arranged and combined to form several nozzle welding schemes and nozzle hole-expansion schemes. Using automatic welding and automatic hole-expansion devices, nozzles are welded onto the precious metal nozzle plate according to the parameter values ​​corresponding to all nozzle welding and hole-expansion schemes. The welded nozzles are then expanded. Welding acceptance data for each nozzle welding scheme and hole-expansion acceptance data for each nozzle hole-expansion scheme are recorded and stored. Finally, the nozzle welding scheme and hole-expansion scheme with the best welding quality are selected from the several welding acceptance data and several hole-expansion acceptance data, respectively. The parameter values ​​corresponding to this nozzle welding and hole-expansion scheme are used as the optimal welding parameters for the nozzle plate and nozzle in Examples 1, 2, and 3, and the optimal hole-expansion parameters for the nozzle, as detailed below: Example 1

[0165] Optimal welding parameters:

[0166] The welding scanning speed is 400ms / hole, the welding direction is linear welding, the welding connection between holes is non-extinguishing arc welding, the welding diameter is +0.5mm of the nozzle outer diameter (the welding diameter is 3.2mm), the welding speed is 350ms / hole, and the initial distance between the bottom of the welding torch and the upper surface of the nozzle plate is 0.8mm.

[0167] The welding current includes the central welding current and the peripheral welding current. The central welding current is 45A, and the peripheral welding current is 53A. The welding current judgment threshold is 3.

[0168] If the actual number of nozzle layers is ≤3, it is determined that the nozzle belongs to the outer nozzle, and the welding torch is connected to the outer welding current of 53A.

[0169] If the actual number of nozzle layers is greater than 3, it is determined that the nozzle belongs to the middle nozzle, and the welding torch is connected to the middle welding current of 45A.

[0170] Optimal hole enlargement parameters:

[0171] The hole reaming scanning speed is 200ms / hole, the hole reaming robot moving speed is 200ms / hole, the drill bit rotation speed is 1000 rpm, the drill bit descent speed is 1mm / s, the initial distance between the bottom of the drill bit and the upper surface of the stencil is 0.6mm, and the drill bit diameter is 1.8mm. Example 2

[0172] Optimal welding parameters:

[0173] The welding scanning speed is 200ms / hole, the welding direction is Z-shaped welding, the welding connection method between holes is arc-extinguishing welding, the arc-extinguishing delay time is 200ms, the welding diameter is +0.5mm of the nozzle outer diameter (the welding diameter is 3.1mm), the welding speed is 200ms / hole, and the initial distance between the bottom of the welding torch and the upper surface of the nozzle plate is 0.6mm.

[0174] The welding current includes the central welding current and the peripheral welding current. The central welding current is 35A, and the peripheral welding current is 40A. The welding current judgment threshold is 1.

[0175] If the actual number of nozzle layers is ≤1, it is determined that the nozzle belongs to the outer nozzle, and the welding torch is connected to the outer welding current of 40A.

[0176] If the actual number of nozzle layers is greater than 1, it is determined that the nozzle belongs to the middle nozzle, and the welding torch is connected to the middle welding current of 35A.

[0177] Optimal hole enlargement parameters:

[0178] The hole reaming scanning speed is 300ms / hole, the hole reaming robot moving speed is 300ms / hole, the drill bit rotation speed is 2000 rpm, the drill bit descent speed is 2mm / s, the initial distance between the bottom of the drill bit and the upper surface of the stencil is 0.8mm, and the drill bit diameter is 1.7mm. Example 3

[0179] Optimal welding parameters:

[0180] The welding scanning speed is 300ms / hole, the welding direction is linear welding, the welding connection method between holes is arc extinguishing welding, the arc extinguishing delay time is 150ms, the welding diameter is +0.5mm of the nozzle outer diameter (the welding diameter is 3.1mm), the welding speed is 300ms / hole, and the initial distance between the bottom of the welding torch and the upper surface of the nozzle plate is 0.1mm.

[0181] The welding current includes the central welding current and the peripheral welding current. The central welding current is 40A, and the peripheral welding current is 45A. The welding current judgment threshold is 2.

[0182] If the actual number of nozzle layers is ≤2, it is determined that the nozzle belongs to the outer nozzle, and the welding torch is connected to the outer welding current of 45A.

[0183] If the actual number of nozzle layers is greater than 2, it is determined that the nozzle belongs to the middle nozzle, and the welding torch is connected to the middle welding current of 40A.

[0184] Optimal hole enlargement parameters:

[0185] The hole reaming scanning speed is 400ms / hole, the hole reaming robot moving speed is 400ms / hole, the drill bit rotation speed is 3000 rpm, the drill bit descent speed is 3mm / s, the initial distance between the bottom of the drill bit and the upper surface of the stencil is 1.0mm, and the drill bit diameter is 1.7mm.

[0186] The quality of the welded sprue plates and nozzles in the three embodiments described above was inspected. It was found that because errors caused by factors affecting welding quality were minimized as much as possible during the welding process, the welding quality of the sprue plates and nozzles was extremely high (the yield rate of nozzle welding was 99.9%~99.95%). Dye penetration testing of the welds (weld width 1.8mm~2.0mm) showed no leakage, and visual inspection revealed extremely high weld fullness. Therefore, this invention can be used for welding different types of sprue plates and nozzles, significantly improving welding quality while ensuring welding efficiency.

[0187] The quality of the reamed nozzles in the three embodiments described above was inspected. Because this invention minimizes errors caused by factors affecting reaming quality during the reaming process, the quality of the reamed nozzles is extremely high (the yield rate of reamed nozzles is 99.9%~99.95%), meeting the requirements. Dye testing was conducted, and no cases of drill bit penetration due to eccentric reaming were observed. Therefore, this invention can be used for reaming nozzles on different types of reaming plates, simultaneously achieving both reaming efficiency and quality requirements.

[0188] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method of welding and reaming a nozzle of a precious metal bushing, characterized by, The method comprises the following steps: 1) setting a welding calibration unit for obtaining optimal welding parameters in the intelligent control system of the automatic welding device, and setting a reaming calibration unit for obtaining optimal reaming parameters in the intelligent control system of the automatic reaming device; 2) determining the optimal welding scheme of the nozzle through welding calibration experiment, comprising the following steps: 2-1) determining the value range of the welding parameters according to the geometric parameters of the to-be-welded tube sheet and nozzle according to the empirical value; 2-2) arranging and combining the values in the value range of the welding parameters to form several trial welding schemes; 2-3) under the control of the welding PLC controller, automatically welding the nozzle assembled on the precious metal tube sheet according to the several trial welding schemes obtained in step 2-2), and recording and storing the acceptance data of each trial welding scheme in the welding calibration unit; 2-4) selecting the trial welding scheme with the best welding quality from the several welding acceptance data as the optimal welding scheme of the tube sheet and nozzle, which is used for automatic welding of the automatic welding device according to the optimal welding scheme; 3) determining the optimal reaming scheme of the nozzle through reaming calibration experiment, comprising the following steps: 3-1) determining the value range of the reaming parameters according to the geometric parameters of the to-be-reamed tube sheet and nozzle according to the empirical value; 3-2) arranging and combining the values in the value range of the reaming parameters to form several trial reaming schemes; 3-3) under the control of the reaming PLC controller, automatically reaming the nozzle welded on the precious metal tube sheet according to the several trial reaming schemes obtained in step 3-2), and recording and storing the acceptance data of each trial reaming scheme in the reaming calibration unit; 3-4) selecting the trial reaming scheme with the best reaming quality from the several reaming acceptance data as the optimal reaming scheme of the tube sheet and nozzle, which is used for automatic reaming of the automatic reaming device according to the optimal reaming scheme; 4) according to the optimal welding parameters in the optimal welding scheme, sequentially welding the nozzles on the precious metal tube sheet under the control of the welding PLC controller of the automatic welding device; 5) according to the optimal reaming parameters of the optimal reaming scheme, sequentially reaming the nozzles on the precious metal tube sheet under the control of the reaming PLC controller of the automatic reaming device.

2. The method of claim 1, wherein the welding and reaming of the nozzle of the precious metal tab is characterized by, The geometric parameters of the tube sheet include the number of tube sheet holes, the diameter of the tube sheet holes, and the thickness of the tube sheet, and the geometric parameters of the nozzle include the outer diameter of the nozzle, the inner diameter of the nozzle, and the height of the nozzle.

3. The method of claim 1, wherein the welding and reaming of the nozzle of the precious metal tab is characterized by, The welding parameters include welding scanning speed, welding direction, inter-hole welding connection mode, welding current, welding current judgment threshold, welding speed, welding diameter, arc extinguishing delay time, and initial distance between the bottom of the welding gun and the upper surface of the tube sheet.

4. The method of claim 1, wherein the welding and reaming of the nozzle of the precious metal tab is characterized by, The reaming parameters include reaming scanning speed, reaming robot moving speed, drill bit rotating speed, drill bit descending speed, drill bit diameter, and initial distance between the bottom of the drill bit and the upper surface of the tube sheet.

5. The method of claim 1, wherein the welding and reaming of the nozzle of the precious metal tab is characterized by, In step 4), under the control of the welding PLC controller of the automatic welding device, the nozzles on the precious metal tube sheet are sequentially welded, comprising: 4-1) turning on the power of the automatic welding device, initializing the state of the automatic welding device, and returning the position of the welding Cartesian robot to the origin; 4-2) By operating the man-machine interface of the automatic welding device, the corresponding optimal welding parameters are selected according to the model of the bushing and the bushing nozzle; 4-3) The precious metal bushing to be welded is clamped on the workbench of the automatic welding device; 4-4) Start the automatic welding device, and weld all the bushing nozzles to be welded on the bushing.

6. The method of claim 1, wherein the method further comprises: In step 5), the bushing nozzles on the precious metal bushing are sequentially reamed under the control of the reaming PLC controller of the automatic reaming device, including: 5-1) Turn on the power of the automatic reaming device, initialize the state of the automatic reaming device, and make the position of the reaming Cartesian coordinate robot return to the origin; 5-2) By operating the man-machine interface of the automatic reaming device, the corresponding optimal reaming parameters are selected according to the model of the bushing and the bushing nozzle; 5-3) The precious metal bushing with the welded bushing nozzles is clamped on the workbench of the automatic reaming device; 5-4) Start the automatic reaming device, and ream the inner holes of the bushing nozzles welded on the precious metal bushing.

7. The method of claim 1, wherein the method further comprises: In step 4), when the automatic welding device welds all the bushing nozzles to be welded on the precious metal bushing, it includes the following two modes: Whole scanning welding mode: (1) Select the group number of the bushing nozzles to be welded or the number of the bushing nozzles through the man-machine interface; (2) The automatic welding device scans and stores the positions of the bushing nozzles to be welded selected in step (1), and then welds the bushing nozzles; Local scanning welding mode: (1) The automatic welding device obtains the position of a bushing nozzle on the bushing by scanning, and then welds the bushing nozzle according to the position of the bushing nozzle; (2) Repeat step (1) until all the bushing nozzles on the bushing are welded.

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