A welding track generation method based on laser packaging of micro-thin parts
By using visual imaging and grayscale transformation technology, combined with manually set acquisition points and distance offsets, accurate welding trajectories are generated, solving the problem of inaccurate welding trajectories for tiny and thin parts, and improving welding yield and product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAMEN JINGHAN AUTOMATION CO LTD
- Filing Date
- 2022-11-30
- Publication Date
- 2026-05-19
AI Technical Summary
Existing technologies are inaccurate in generating welding trajectories for tiny, thin parts, resulting in high product defect rates and difficulty in finding the true welding trajectory.
Projected images are acquired by a vision imaging unit. The boundary line between the workpiece and the welding fixture is segmented by grayscale transformation and a manually set threshold. Combined with manually set acquisition points and distance offsets, an accurate welding trajectory is fitted. The outer edge of the workpiece is used as a reference to adjust the welding path to overcome actual deformation and interference.
It improves the accuracy of welding trajectories and yield, reduces reliance on high-precision vision equipment, and achieves a yield rate of up to 99% and product quality consistency.
Smart Images
Figure CN115797385B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser welding, and more specifically to a method for generating welding trajectories based on laser packaging of tiny, thin parts. Background Technology
[0002] Currently, laser welding is a widely used method in the packaging of thin-walled devices such as metal-encapsulated communication ICs, aerospace relays, and thick-film integrated circuits. However, generating laser welding trajectories that meet product packaging requirements and welding processes is one of the industry's pain points.
[0003] In general, the industry commonly uses two methods to generate laser trajectories: 1. Directly importing the seam between the product and its casing from the product's CAD drawings as the trajectory into the system for welding. 2. Using an imaging system or laser sensor to directly locate the connection seam between the device's base and casing, and using this connection seam as the weld seam. Both methods have the following significant challenges:
[0004] The welding trajectory is directly taken from the joint between the base and the outer shell in the product's CAD drawings, assuming that the shape and size of the device's outer shell and base are completely consistent with the drawings. However, in actual production, the device's outer shell is obtained by stamping and stretching the material. There is a certain deviation between the actual outer shell and the drawing. (For example, the theoretical projection of the outer shell of an aerospace relay is a rectangle with four rounded chamfers, but the actual product has a drum-shaped projection due to the deformation of the metal after stress release during stretching.) If welding is carried out according to the standard graphic trajectory, there is a risk of encapsulation leakage. Since the internal chips and other components are expensive, problems in the welding process can lead to the scrapping of chips worth thousands of yuan.
[0005] Imaging systems or laser sensors are used to directly locate the seam between the device's base and housing. However, this method is problematic because the seam is only 0.1-0.2mm wide, and the base has interference elements such as heat insulation grooves. Furthermore, the welded surface of the housing lacks flatness requirements, resulting in pits and unevenness. These factors significantly interfere with the identification by the imaging system or laser. The imaging system requires high processing power; even slight errors can lead to failure in locating the seam or incorrect tracking. Manual judgment and correction of the actual searched trajectory are often necessary. Additionally, because the base and housing are made of different materials with varying thermal conductivity, using the seam as a weld seam may still result in weld cracking due to differences in thermal deformation.
[0006] In summary, existing methods for generating welding trajectories for tiny, thin parts still need further improvement. Summary of the Invention
[0007] The purpose of this invention is to overcome the aforementioned defects or problems in the background technology and provide a welding trajectory generation method based on laser packaging of tiny thin parts. This method has a simple structure, is easy to manufacture, is easy to implement, and has low cost. It solves the problem that existing welding trajectories are inaccurate, it is difficult to find the true welding trajectory, and ultimately leads to a high product defect rate.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] A method for generating welding trajectories based on laser packaging of tiny thin parts, the method comprising:
[0010] A projected image is acquired and stored by a visual imaging unit and grayscale transformation is performed. The boundary line between the workpiece and the welding fixture is segmented from the projected image using a manually set grayscale threshold. The boundary line is configured to be a combination of lines connecting several manually set acquisition points.
[0011] The boundary line is shifted inward by a manually set first distance and compared with a manually set first trajectory. If the sum of the areas of the regions formed by the intersection of the line and the first trajectory and the corresponding collection point is greater than the manually set area threshold, and the sum of the absolute values of the distances from each collection point to the first trajectory along the direction perpendicular to the first trajectory that fall within the manually set first distance range is greater than the manually set quantity value, then the line is a valid line.
[0012] Remove the sampling points that are greater than the first distance range value set by the user, and use the critical value of the first distance range value that the removed sampling points are offset to in the first trajectory direction as the new sampling points;
[0013] The average offset of the distance from the new sampling point and the sampling point falling within the first distance range set by the human to the first trajectory is used as the landing position of each sampling point, and the second trajectory is fitted.
[0014] The welding trajectory is generated by manually setting a second distance and offsetting the workpiece with a large heat-conducting surface or heat-conducting grooves, based on the second trajectory.
[0015] Furthermore, the sampling line is explored perpendicularly to the direction of the workpiece in the projected image using a manually set number of sampling lines, and gray values of points at manually set intervals are collected on the sampling line. When the points on the sampling line go from dark to light and a downward abrupt change occurs, the first point with the downward abrupt change is determined as the collection point.
[0016] Furthermore, the decrease in grayscale value is defined as the grayscale value of the sampled point being less than the manually set grayscale threshold for a number of times before the sampled point, and the grayscale value of the sampled point being greater than the manually set grayscale threshold for a number of times after the sampled point.
[0017] Furthermore, for the arc-shaped portion located on the boundary line, the sampling point is explored in the direction of the sampling line toward the center of the arc-shaped portion.
[0018] Furthermore, the sum of the areas formed by the intersection of the line to the first trajectory and the corresponding collection point accounts for more than 70% of the total area.
[0019] Furthermore, the sum of the number of data points whose absolute distance values from each data collection point to the first trajectory fall within a manually set first distance range value accounts for more than 70% of the total number of data collection points.
[0020] Furthermore, the absolute value of the distance from each collection point to the first trajectory ranges from 0.1 to 0.3 mm.
[0021] Furthermore, the range of the artificially set second distance is 0.1-0.3 mm.
[0022] Furthermore, the average distance from the collection point to the first trajectory is one-half of the distance value.
[0023] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:
[0024] (1) This invention provides a welding trajectory generation method based on laser packaging of tiny thin parts. It has a simple structure, is easy to manufacture, easy to implement and low cost. It solves the problem that the existing welding trajectory is inaccurate and it is difficult to find the real welding trajectory, which ultimately leads to a high product defect rate. This invention breaks away from the traditional method of finding the welding trajectory by relying solely on vision. It uses the outer edge of the workpiece as a reference, which reduces the difficulty of finding the trajectory. It accurately fits the boundary line (connection line) with grayscale changes and manually set collection points. The initial trajectory of the welding trajectory is obtained by offsetting the boundary line as a reference line. After comparison, judgment and correction with the manually set theoretical curve (i.e., the first trajectory), a new trajectory is fitted. Then, the human offset is performed to finally obtain the welding trajectory. This trajectory is the real (actual) welding trajectory (weld). It has higher accuracy and does not rely on high-precision vision equipment to grasp the trajectory. The actual welding trajectory or path can be adjusted according to the changes of the actual object. The yield rate of the welded product is as high as 99%, and the quality is uniform and the appearance is exquisite.
[0025] (2) The present invention explores gray values by using artificially set sampling lines at intervals and perpendicular to the boundary lines, and marks the sampling points in the form of abrupt changes as the benchmark for subsequent offset and comparison correction. This method obtains the actual boundary lines more accurately, with higher precision, and the fitted lines are closer to the contour of the workpiece, providing a strong premise for subsequently fitting the actual welding trajectory. Attached Figure Description
[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments are briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is the front view of the projected image described in this invention;
[0028] Figure 2 This is a schematic diagram illustrating the generation and offset of the boundary line by a manually set first distance as described in this invention.
[0029] Figure 3 This is a schematic diagram illustrating the process of locating collection point A according to the present invention;
[0030] Figure 4 This is a schematic diagram comparing the offset boundary line with the first trajectory as described in this invention;
[0031] Figure 5 As described in this invention Figure 4 Enlarged view of section E in the middle;
[0032] Figure 6 This is a schematic diagram of the new collection points obtained after removing collection points outside the manually set range values as described in this invention;
[0033] Figure 7 This is a schematic diagram of fitting the second trajectory according to the present invention. Detailed Implementation
[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0035] Unless otherwise expressly defined, the use of terms such as "first," "second," or "third" in the claims, description, and accompanying drawings of this invention is for distinguishing different objects and not for describing a specific order.
[0036] Unless otherwise expressly defined, in the claims, description, and accompanying drawings of this invention, the use of directional terms such as "center," "lateral," "longitudinal," "horizontal," "vertical," "top," "bottom," "inner," "outer," "upper," "lower," "front," "rear," "left," "right," "clockwise," and "counterclockwise" to indicate orientation or positional relationships is based on the orientation and positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the specific scope of protection of this invention.
[0037] Unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" used in the claims, description and drawings of this invention should be interpreted broadly to refer to any connection in which there is no displacement or relative rotation relationship between the two parties, including non-removable fixed connection, detachable fixed connection, integral connection and fixed connection by other means or components.
[0038] In the claims, description and drawings of this invention, the use of the terms "comprising", "having" and variations thereof is intended to mean "including but not limited to".
[0039] See Figure 1 As shown, this invention provides a welding trajectory generation method based on laser packaging of micro-thin parts, which is used for laser welding of micro-thin parts to generate actual weld seams (i.e., welding trajectories). Taking the welding and packaging of a relay as an example, the relay shell and base are laser welded together. It should be noted that, due to the thin wall thickness of the shell during the stretching and forming process, phenomena such as peripheral wall bulging often occur.
[0040] The welding trajectory generation method of the present invention includes:
[0041] like Figure 1 , 2 As shown, a projected image is acquired and stored by a visual imaging unit and grayscale transformation is performed. The boundary line L between the workpiece 3 and the welding fixture 4 is segmented from the projected image 2 using a manually set grayscale threshold. The boundary line L is configured to be a combination of lines connecting several manually set acquisition points A.
[0042] It should be noted that in this invention, the sampling line 5 is used to explore vertically in the direction of the workpiece 3 in the projected image 2, and gray values of points at human-defined intervals are collected on the sampling line 5. If the gray value of a point decreases from dark to light and there is a sudden drop, then the first point of the sudden drop is determined to be the sampling point A.
[0043] like Figure 1-3As shown, the number of sampling lines 5 is determined by the size of the shell. Different numbers of sampling lines 5 are set. For example, the shell in this embodiment is theoretically composed of 4 straight segments and 4 arc segments. The straight segments are arranged in parallel at intervals of 0.02mm according to their length. Each sampling line 5 is set perpendicular to the straight segments and explores from the tooling towards the shell 31 and the base 32.
[0044] During the exploration process, points A1, A2, ... are set at regular intervals along the sampling line 5, and their grayscale values are obtained. If the grayscale value of a point falls within the set grayscale threshold range, and the grayscale values of points A-1, A-2, ... before point A (e.g., the first 5 points) are all less than the set grayscale threshold, and the grayscale values of points A+1, A+2, ... after point A (e.g., the last 5 points) are all greater than the set grayscale threshold, then the point is determined to be a usable sampling point A. In this way, sampling points A on the straight line segment are obtained.
[0045] In addition, during this exploration process, for the sampling line 5 on the arc segment (here the arc segment is the chamfer position connected by two straight line segments), it is explored with the sampling line 5 towards the center of the circle, and the sampling point A located at the position of the arc segment is obtained in the manner of confirming the sampling point A as described above.
[0046] Then, the collection points A are smoothly connected to form a complete line L, which is the boundary line L. The boundary line L connected by fitting in this way is more accurate, and the actual boundary can be accurately obtained even if there are bulges or twists.
[0047] like Figure 2-6 As shown, the boundary line L is offset inward by a manually set first distance N, and compared with the first trajectory H set by the human. It should be noted that the manually set first distance N here is the thickness of the workpiece 3 (outer shell 31), for example, 1-1.2mm. The boundary line L is offset inward. The first trajectory H mentioned in this invention is a theoretical welding trajectory, such as the trajectory set by CAD drawing. The offset boundary line L is compared with the theoretical welding trajectory.
[0048] The comparison process first determines whether the connection (i.e., boundary line L) is a valid connection, which requires the following two conditions:
[0049] Firstly: If the sum of the areas of the region formed by the intersection of the line L and the first trajectory H and the corresponding acquisition point A is greater than the manually set area threshold (the manually set area threshold here is exemplified by accounting for more than 70% of the total area); it should be noted that the region formed by the intersection of the line L and the first trajectory H and the corresponding acquisition point A through a straight line.
[0050] Secondly: The sum of the number of sampling points A whose absolute values along the direction perpendicular to the first trajectory H fall within the first distance range N is greater than the manually set number (i.e., the number of sampling points A falling within this range is more than 70% of the total number of sampling points A); specifically, the distance P from sampling point A to the first trajectory H, and the absolute value of this distance P falls within the first distance range (e.g., if the absolute value of this distance is 0.12, falling within the first distance range 0.1≤P≤0.3, then sampling point A is judged to be a valid sampling point A), and the total number of valid sampling points A is P 总 If the total amount collected at point A is greater than or exceeds 70%, then this condition is met.
[0051] If both of the above conditions are met simultaneously, then the connection L is a valid connection L; otherwise, the connection L is re-evaluated.
[0052] Then, the sampling point A that is greater than or exceeds the first distance range value N set by the human; and the position of the sampling point A that is offset to the first trajectory H direction to the critical value of the first distance range value of 0.3mm is taken as the new sampling point A, that is, the position of the sampling point A that was removed is shifted to the critical value of 0.3mm, so that the sampling point A will not be reduced and the shape of the trajectory will not be changed.
[0053] Using the average offset of the distances from the new sampling point A to the first trajectory H, and the distances falling within the artificially set first distance N range, as the landing position of each sampling point A, a second trajectory is fitted; the average offset mentioned in this invention is that the average distance from the sampling point A to the first trajectory H is half of the distance value; that is, each sampling point A1 (whether it is a new sampling point A or an existing sampling point A) is offset again by a certain distance in the direction perpendicular to the first trajectory H, and this distance is half (i.e., half) of the distance from the sampling point A to the first trajectory H, forming a new position for each sampling point A after the offset; (e.g. Figure 7 As shown, the various acquisition points A at the new location are connected in series to form a new welding trajectory L1 (i.e., the second trajectory);
[0054] Finally, the actual welding trajectory is generated by offsetting the workpiece 3 (in this invention, it is biased towards the base 32) with a large heat-conducting surface, heat-conducting groove 7, or low laser absorption rate, based on the second trajectory. It should be noted that, due to the different thermal conductivity of the outer shell 31 and the base 32, in order to prevent the internal components from being damaged by high temperature, the part with better thermal conductivity, large heat-conducting area, or heat-conducting groove is offset by a certain distance.
[0055] The final generated welding trajectory is close to the actual weld, and the welded finished products have high precision and good quality, with a yield rate of over 98%.
[0056] This invention provides a welding trajectory generation method for laser packaging of micro-thin parts. It features a simple structure, easy fabrication, and low cost, solving the problems of inaccurate welding trajectories and difficulty in finding the true welding trajectory, ultimately leading to high product defect rates. This invention breaks away from the traditional method of solely relying on visual tracking of the welding trajectory. Instead, it uses the outer edge of the workpiece as a reference, reducing the difficulty of finding the trajectory and accurately fitting the boundary line (connecting lines) using grayscale changes and manually set sampling points. Using this boundary line as a reference line, an initial welding trajectory is obtained by offsetting. This initial trajectory is then compared, judged, and corrected against a manually set theoretical curve (i.e., the first trajectory) to fit a new trajectory, followed by further manual offsetting. The final obtained welding trajectory is the actual welding trajectory (weld seam), which is more accurate and does not rely on high-precision vision equipment for trajectory capture. The actual welding trajectory or path can be adjusted according to changes in the actual object. The yield rate of the welded products is as high as 99% or more, with uniform quality and exquisite appearance. This invention explores grayscale values at intervals and perpendicular to the boundary line by manually set sampling lines, and marks the sampling points with abrupt changes as the benchmark for subsequent offset and comparison correction. This method obtains the actual boundary line more accurately, with higher precision. The fitted line is closer to the contour of the workpiece, providing a strong premise for subsequent fitting of the actual welding trajectory.
[0057] The description of the above specification and embodiments is used to explain the scope of protection of the present invention, but does not constitute a limitation on the scope of protection of the present invention.
Claims
1. A method for generating welding trajectories based on laser packaging of micro-thin parts, characterized in that: The welding trajectory generation method includes: A projected image is acquired and stored by a visual imaging unit and subjected to grayscale transformation. The boundary line between the workpiece and the welding fixture is segmented in the projected image using a manually set grayscale threshold. The boundary line is configured to be composed of a combination of lines connecting a number of manually set sampling points. A number of sampling lines are explored perpendicularly to the direction of the workpiece in the projected image using a manually set number of sampling lines. The grayscale values of points at manually set intervals are collected on the sampling lines. When the points on the sampling lines decrease in color from dark to light and a sudden drop occurs, the first point with the sudden drop is determined to be the sampling point. The boundary line is shifted inward by a manually set first distance and compared with a manually set first trajectory. If the sum of the areas of the regions formed by the intersection of the line and the first trajectory and the corresponding collection point is greater than the manually set area threshold, and the sum of the absolute values of the distances from each collection point to the first trajectory along the direction perpendicular to the first trajectory that fall within the manually set first distance range is greater than the manually set quantity value, then the line is a valid line. Remove the sampling points that are greater than the first distance range value set by the user, and use the critical value of the first distance range value that the removed sampling points are offset to in the first trajectory direction as the new sampling points; The average offset of the distance from the new sampling point and the sampling point falling within the first distance range set by the human to the first trajectory is used as the landing position of each sampling point, and the second trajectory is fitted. The welding trajectory is generated by manually setting a second distance and offsetting the workpiece with a large heat-conducting surface or heat-conducting grooves, based on the second trajectory.
2. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 1, characterized in that: The occurrence of a sudden decrease in grayscale value is defined as follows: the grayscale values of the points before the sampling point are all less than the manually set grayscale threshold, and the grayscale values of the points after the sampling point are all greater than the manually set grayscale threshold.
3. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 2, characterized in that: The sampling point is explored along the arc-shaped portion of the boundary line, with the sampling line pointing towards the center of the arc-shaped portion.
4. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 1, characterized in that: The sum of the areas formed by the intersection of the line and the first trajectory and the corresponding collection point accounts for more than 70% of the total area.
5. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 4, characterized in that: The sum of the number of data collection points whose absolute distance values from each collection point to the first trajectory fall within a manually set first distance range value accounts for more than 70% of the total number of data collection points.
6. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 5, characterized in that: The absolute value of the distance from each collection point to the first trajectory ranges from 0.1 to 0.3 mm.
7. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 1, characterized in that: The range of the artificially set second distance is 0.1-0.3 mm.
8. The welding trajectory generation method based on laser packaging of micro-thin parts as described in claim 1, characterized in that: The average distance from the collection point to the first trajectory is one-half of the distance value.