Welding device for touch screen production

Abstract

The invention belongs to the technical field of welding devices, and particularly relates to a welding device for touch screen production, which comprises a welding table, a turntable is mounted in the middle of the top of the welding table, a coating mechanism, a tin supplementing mechanism and a welding mechanism are arranged at the top of the welding table, and the welding mechanism comprises a fixing frame fixed at the top of the welding table; a first moving platform is fixed to the inner side face of the fixing frame, a welding gun is fixed to the free end of the first moving platform, and the tin supplementing mechanism comprises a tin paste thickness collecting module used for detecting the thickness of tin paste; the morphology acquisition module is used for detecting the morphology of the solder paste; and the execution mechanism is used for trace tin supplement. According to the device, the solder paste coating condition is monitored in real time through the solder paste thickness collecting module and the morphology collecting module, the control module judges the coating quality according to an accurate evaluation coefficient calculation formula, unqualified solder paste coating can be accurately recognized, the tin supplementing mechanism can conduct trace tin supplementing in a targeted mode, the welding quality is greatly improved, and the production efficiency is improved. And the defective rate is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of welding devices, and particularly to a welding device for touch screen production. Background Art

[0002] During the automated production process of touch screens, it is necessary to weld flexible circuits to the touch screen main body to achieve circuit connection. Depending on the production method, the welding method is also different. For example, in automated or semi-automated welding operations, laser welding technology is often used for welding. The specific principle is to first fix the touch screen and the flexible circuit board on the fixture, then apply solder paste to the connection between the flexible circuit board and the touch screen, and then use the laser emitted by the laser welding machine to heat the solder paste.

[0003] The welding quality directly affects the performance and service life of the touch screen. There are some problems with traditional touch screen welding devices. On the one hand, there is a lack of precise control in the solder paste coating process, and uneven solder paste thickness and poor morphology often occur, which leads to inconsistent firmness of the welding points and easily causes problems such as false soldering and de-soldering. On the other hand, once there are problems with the solder paste coating quality, it often requires manual inspection and re-soldering, which is inefficient and difficult to ensure the accuracy and consistency of re-soldering. With the continuous expansion of the touch screen market and the increasing requirements for product quality, it is urgent to develop a welding device that can achieve precise solder paste coating detection and re-soldering functions. Summary of the Invention

[0004] Based on the technical problems existing in the prior art, the present invention proposes a welding device for touch screen production.

[0005] A soldering device for touch screen production proposed by the present invention includes a soldering table. At the middle position of the top of the soldering table, a turntable is installed. On the top of the soldering table, there are a coating mechanism, a solder replenishing mechanism, and a soldering mechanism surrounding the turntable. The soldering mechanism includes a fixed frame fixed on the top of the soldering table. On the inner side of the fixed frame, a first moving platform is fixed. At the free end of the first moving platform, a soldering gun is fixed. The solder replenishing mechanism includes: a solder paste thickness acquisition module, arranged on the coating mechanism, for detecting the thickness of the solder paste after coating in real time; a morphology acquisition module, arranged beside the coating mechanism, for detecting the morphology of the solder paste after coating in real time; an execution mechanism, for performing micro solder replenishment. The flexible circuit board and the touch screen are installed on the turntable through a jig. After the turntable rotates, it first moves the flexible circuit board and the touch screen to the coating mechanism. At this time, the coating mechanism extrudes the solder paste and smears it at the designated position. During the coating process, the solder paste thickness acquisition module detects the thickness of the solder paste after coating in real time, the morphology acquisition module detects the morphology of the solder paste after coating in real time, the control module receives the data collected by the solder paste thickness acquisition module and the morphology acquisition module in real time, and conducts comprehensive analysis, and then generates an evaluation coefficient. By comparing the evaluation coefficient with a pre-set evaluation coefficient reference threshold, it is judged whether the quality of the solder paste coating is qualified, and the working state of the execution mechanism is controlled according to the comparison result. If the quality of the solder paste coating is unqualified, then the turntable drives the circuit board and the touch screen to move to the solder replenishing mechanism. The execution mechanism will be started, and micro solder replenishment will be performed at the unqualified coating place.

[0006] Preferably, the coating mechanism includes a third moving platform fixed on the top of the soldering table. At the free end of the third moving platform, an installation frame is fixed. On the installation frame, an injection cylinder is fixed. At the top of the injection cylinder, a piston inserted into the interior of the injection cylinder is provided. On the top of the installation frame, an electric push rod is fixed. The output shaft of the electric push rod is fixedly connected with a connecting block, and the connecting block is fixedly connected with the piston. The third moving platform drives the injection cylinder to move to a predetermined position according to the path set by the system. Then, the output shaft of the electric push rod drives the connecting block and the piston to move downward, extruding the solder paste in the injection cylinder from the bottom end of the injection cylinder. At the same time, the third moving platform drives the injection cylinder to translate along the welding position of the flexible circuit board and the touch screen along the set path, thereby realizing the coating of the solder paste.

[0007] Preferably, the execution mechanism includes a second moving platform and a piezoelectric dispensing valve. The second moving platform is fixed on the top of the soldering table, and the piezoelectric dispensing valve is fixed at the free end of the second moving platform. When solder replenishment is required, the second moving platform drives the piezoelectric dispensing valve to move to the position where solder replenishment is required according to the path given by the system, and then micro solder replenishment is performed through the piezoelectric dispensing valve.

[0008] Preferably, a hanging bracket is fixedly connected to the bottom end of the mounting bracket, the solder paste thickness acquisition module is fixedly connected to the bottom end of the hanging bracket, the morphology acquisition module is fixedly mounted on the top of the soldering table through a support frame, and the control module is fixedly mounted on the third moving platform; in this way, it is possible to better detect the thickness of the applied solder paste in real time through the solder paste thickness acquisition module, and better detect the morphology of the applied solder paste in real time through the morphology acquisition module.

[0009] Preferably, a feed pipe head is installed on the barrel wall of the syringe; first, connect the feed pipe head to an external solder paste supply system. When the solder paste in the syringe is used up, the piston can be lifted to the highest position by the electric push rod, and then the solder paste can be injected into the syringe through the solder paste supply system, so that the replenishment of the solder paste can be quickly completed and the overall soldering efficiency can be improved.

[0010] Preferably, a heater is installed at a position close to the bottom end of the barrel wall of the syringe, and a button is arranged on the side of the heater; if the device is restarted after being stopped for a period of time, since the remaining solder paste in the syringe will solidify after being exposed for a long time and then block the bottom outlet of the syringe, at this time, the heater can be energized by pressing the button, and then the solder paste in the syringe can be heated and melted, so that it will not affect the secondary use.

[0011] Preferably, the actuator further includes a laser power regulator disposed in the soldering gun; the laser power regulator forms a closed-loop control with the quality detection system. For example, when it is detected that the solder paste thickness increases by 10 μm, the power will be increased from 300 W to 325 W within 50 μs to ensure the consistency of the penetration depth.

[0012] Preferably, the control logic of the control module for the working state of the actuator is as follows:

[0013] First, during the process of solder paste coating, detect the thickness and morphology of the solder paste after coating;

[0014] Second, the control module receives the thickness and morphology data information in real time and calculates the evaluation coefficient;

[0015] Third, when K≥0.8, it is judged as qualified, when K<0.7, solder replenishment is triggered, and when 0.7≤K<0.8, it enters the re-inspection process.

[0016] Preferably, the calculation formula of the evaluation coefficient K is:

[0017]

[0018] In the formula, α, β, γ: the weights of the thickness parameters, the weight of the coverage rate, the coefficient of the uniformity penalty term, T avg : the average thickness of the solder paste coating, T std : the standard thickness value, A: the actual coverage rate of the solder pad, Aideal : Ideal coverage, Thickness standard deviation.

[0019] Preferably, the average thickness of the solder paste coating is T avg It is the arithmetic mean of the thickness of multiple measuring points actually detected, and the calculation formula is:

[0020]

[0021] Where, T i is the actual coating thickness of solder paste at the i-th measurement point.

[0022] Compared with the prior art, the present invention provides a welding device for touch screen production, which has the following beneficial effects:

[0023] 1. A soldering device for touch screen production, which monitors the solder paste coating in real time through the solder paste thickness acquisition module and the morphology acquisition module. The control module determines the coating quality based on the precise evaluation coefficient calculation formula, and can accurately identify unqualified solder paste coating. The tin replenishment mechanism can carry out targeted micro-tin replenishment, which greatly improves the welding quality and reduces the defective rate.

[0024] 2. A welding device for touch screen production. The injection tube head installed on the wall of the injection barrel can be quickly connected to the external solder paste supply system. When the solder paste is used up, the piston is lifted by the electric push rod to quickly complete the solder paste replenishment, reduce downtime, and further improve production efficiency.

[0025] 3. A welding device for touch screen production. The heater installed near the bottom of the syringe and the button on the side can easily solve the problem of solder paste solidification blocking the outlet when the device is restarted after shutdown, ensuring the normal operation of the device without affecting the production progress.

[0026] 4. A welding device for touch screen production. The laser power regulator in the welding gun forms a closed-loop control with the quality detection system. The laser power is adjusted in real time according to the detected change in solder paste thickness to ensure the consistency of the melting depth and improve the stability of the welding quality.

[0027] 5. A welding device for touch screen production. The control module has a clear and definite control logic for the working status of the actuator. Through the detection of solder paste coating thickness and morphology, data processing and grading according to the evaluation coefficient, the quality control of the entire welding process is more scientific and standardized. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of a welding device for touch screen production proposed by the present invention;

[0029] Figure 2Schematic diagram of the overall structure of a welding device for touch screen production proposed by the present invention;

[0030] Figure 3 Schematic diagram of the installation structure among the solder paste thickness acquisition module, topography acquisition module and syringe of a welding device for touch screen production proposed by the present invention;

[0031] Figure 4 Schematic diagram of the internal structure of the syringe of a welding device for touch screen production proposed by the present invention;

[0032] Figure 5 Schematic diagram of the structure of the soldering gun of a welding device for touch screen production proposed by the present invention;

[0033] Figure 6 Schematic diagram of the structure of the actuator of a welding device for touch screen production proposed by the present invention.

[0034] In the figure: 1, welding table; 2, turntable; 3, fixing frame; 4, soldering gun; 5, first moving platform; 6, solder paste thickness acquisition module; 7, topography acquisition module; 8, control module; 9, mounting frame; 10, syringe; 11, piston; 12, electric push rod; 13, connecting block; 14, injection tube head; 15, heater; 16, button; 17, second moving platform; 18, piezoelectric dispensing valve; 19, support frame; 20, hanging bracket; 21, third moving platform. Specific embodiments

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0036] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0037] Refer to Figures 1-6 , a welding device for touch screen production, including a welding table 1. A turntable 2 is installed at the middle position of the top of the welding table 1. A coating mechanism, a tin replenishing mechanism and a welding mechanism are arranged around the turntable 2 at the top of the welding table 1. The welding mechanism includes a fixing frame 3 fixed to the top of the welding table 1. A first moving platform 5 is fixed to the inner side of the fixing frame 3. A soldering gun 4 is fixed to the free end of the first moving platform 5. The tin replenishing mechanism includes:

[0038] The solder paste thickness acquisition module 6 is arranged on the coating mechanism and is used for detecting the thickness of the coated solder paste in real time;

[0039] The morphology acquisition module 7 is arranged beside the coating mechanism and is used for detecting the morphology of the coated solder paste in real time;

[0040] The actuator is used for micro solder replenishment;

[0041] It should be noted that the solder paste thickness acquisition module 6 can be a laser confocal displacement sensor or other devices capable of detecting the thickness of the coated solder paste in real time. The morphology acquisition module 7 can be a 5-megapixel global shutter camera or other devices capable of detecting the morphology of the coated solder paste in real time. The control module 8 is an embedded controller (such as the STM32 series) integrated with a data fusion algorithm. Therefore, the solder paste thickness acquisition module 6, the morphology acquisition module 7, and the control module 8 are not specifically limited here and can be selected according to actual needs;

[0042] During use, the flexible circuit board and the touch screen are installed on the turntable 2 through a jig. After the turntable 2 rotates, the flexible circuit board and the touch screen are first moved to the coating mechanism. At this time, the coating mechanism extrudes the solder paste and smears it at the specified position. During the coating process, the solder paste thickness acquisition module 6 detects the thickness of the coated solder paste in real time, the morphology acquisition module 7 detects the morphology of the coated solder paste in real time, the control module 8 receives the data collected by the solder paste thickness acquisition module 6 and the morphology acquisition module 7 in real time, conducts comprehensive analysis, then generates an evaluation coefficient, compares the evaluation coefficient with a pre-set evaluation coefficient reference threshold to determine whether the solder paste coating quality is qualified, and controls the working state of the actuator according to the comparison result. If the solder paste coating quality is unqualified, then the turntable 2 drives the circuit board and the touch screen to move to the solder replenishment mechanism, and the actuator will be activated to perform micro solder replenishment at the unqualified coating position.

[0043] Among them, the coating mechanism includes a third moving platform 21 fixed to the top of the welding table 1. A mounting frame 9 is fixed to the free end of the third moving platform 21. An injection cylinder 10 is fixed to the mounting frame 9. A piston 11 inserted into the interior of the injection cylinder 10 is arranged at the top of the injection cylinder 10. An electric push rod 12 is fixed to the top of the mounting frame 9. The output shaft of the electric push rod 12 is fixedly connected to a connecting block 13, and the connecting block 13 is fixedly connected to the piston 11;

[0044] During use, the third moving platform 21 drives the injection cylinder 10 to move to a predetermined position according to the path set by the system. Then the output shaft of the electric push rod 12 drives the connecting block 13 and the piston 11 to move downward, extruding the solder paste in the injection cylinder 10 from the bottom end of the injection cylinder 10. At the same time, the third moving platform 21 drives the injection cylinder 10 to translate along the welding position of the flexible circuit board and the touch screen along the set path, thereby realizing the coating of the solder paste.

[0045] Among them, the actuator includes a second mobile platform 17 and a piezoelectric dispensing valve 18. The second mobile platform 17 is fixed on the top of the welding table 1, and the piezoelectric dispensing valve 18 is fixed on the free end of the second mobile platform 17;

[0046] During use, when solder replenishment is required, the second mobile platform 17 drives the piezoelectric dispensing valve 18 to move to the position where solder replenishment is needed according to the path given by the system, and then micro solder replenishment is performed through the piezoelectric dispensing valve 18.

[0047] Among them, a hanging bracket 20 is fixedly connected to the bottom end of the mounting bracket 9, the solder paste thickness acquisition module 6 is fixedly connected to the bottom end of the hanging bracket 20, the topography acquisition module 7 is fixed on the top of the welding table 1 through a support frame 19, and the control module 8 is fixed on the third mobile platform 21;

[0048] During use, in this way, it is possible to better detect the thickness of the applied solder paste in real time through the solder paste thickness acquisition module 6, and better detect the topography of the applied solder paste in real time through the topography acquisition module 7.

[0049] Furthermore, a feed pipe head 14 is installed on the barrel wall of the syringe 10;

[0050] During use, first connect the feed pipe head 14 to an external solder paste supply system. When the solder paste in the syringe 10 is used up, the piston 11 can be lifted to the highest position by the electric push rod 12, and then the solder paste is injected into the syringe 10 through the solder paste supply system, so that the replenishment of the solder paste can be quickly completed, improving the overall welding efficiency.

[0051] Furthermore, a heater 15 is installed on the barrel wall of the syringe 10 near the bottom end, and a button 16 is arranged on the side of the heater 15;

[0052] During use, if the device is restarted after being shut down for a period of time, since the remaining solder paste in the syringe 10 will solidify after being exposed for a long time and then block the bottom outlet of the syringe 10, at this time, the heater 15 can be powered on by pressing the button 16, and then the solder paste in the syringe 10 can be heated to melt it, so that it will not affect the secondary use.

[0053] Furthermore, the actuator further includes a laser power regulator arranged in the welding torch 4;

[0054] During use, the laser power regulator forms a closed-loop control with the quality detection system. For example, when it is detected that the solder paste thickness increases by 10 μm, the power will be increased from 300 W to 325 W within 50 μs to ensure the consistency of the penetration depth.

[0055] In another embodiment, the control logic for automatically performing micro solder replenishment at the unqualified coating areas through the cooperation among the solder paste thickness acquisition module 6, the topography acquisition module 7, the control module 8 and the actuator is as follows:

[0056] I. During the solder paste coating process, detect the thickness and topography after the solder paste is coated;

[0057] II. The control module 8 receives the thickness and topography data information in real time and calculates the evaluation coefficient;

[0058] III. When K≥0.8, it is determined as qualified; when K<0.7, solder replenishment is triggered; when 0.7≤K<0.8, enter the re-inspection process.

[0059] Preferably, the calculation formula of the evaluation coefficient K is:

[0060]

[0061] In the formula, α, β, γ: the weights of the thickness parameters, the weight of the coverage rate, the coefficient of the uniformity penalty term, T avg : the average thickness of the solder paste coating, the arithmetic mean of the thicknesses of multiple measurement points actually detected, calculation formula: T std : the standard thickness value, A: the actual coverage rate of the solder pad (the proportion of the solder paste coverage area quantified by the vision system), A ideal : the ideal coverage rate (the optimal value determined based on DOE experiments), The standard deviation of the thickness (characterizing the uniformity of the solder paste thickness distribution), the calculation formula is:

[0062] This evaluation coefficient K realizes the pre-judgment of the pre-welding quality by quantifying the process states of the three dimensions of thickness, coverage rate and uniformity.

[0063] It should be understood that in various embodiments of the present application, the magnitudes of the sequence numbers of the above processes do not mean the order of execution is prior or posterior. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0064] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0065] In several embodiments provided by this application, it should be understood that the disclosed overall system, device, and method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another overall system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling, direct coupling, or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical, or other forms.

[0066] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0067] In addition, in each embodiment of this application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0068] As described above, this is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claimed rights.

Claims

1. A welding device for touch screen production, comprising a welding table (1), characterized in that, A turntable (2) is installed at the middle position of the top of the soldering table (1). A coating mechanism, a tin replenishing mechanism and a soldering mechanism are arranged on the top of the soldering table (1) around the turntable (2). The soldering mechanism includes a fixed frame (3) fixed on the top of the soldering table (1). A first moving platform (5) is fixed on the inner side of the fixed frame (3). A soldering gun (4) is fixed at the free end of the first moving platform (5). The tin replenishing mechanism includes: A solder paste thickness acquisition module (6), which is arranged on the coating mechanism and is used for detecting the thickness of the solder paste after coating in real time; A morphology acquisition module (7), which is arranged beside the coating mechanism and is used for detecting the morphology of the solder paste after coating in real time; An execution mechanism, which is used for replenishing tin in a small amount; The control module (8) receives the data collected by the solder paste thickness acquisition module (6) and the morphology acquisition module (7), generates an evaluation coefficient, compares it with a preset reference threshold, and controls the working state of the execution mechanism according to the comparison result.

2. The welding device for touch screen production according to claim 1, characterized in that, The coating mechanism includes a third moving platform (21) fixed on the top of the soldering table (1). An installation frame (9) is fixed at the free end of the third moving platform (21). An injection cylinder (10) is fixed on the installation frame (9). A piston (11) inserted into the inside of the injection cylinder (10) is arranged at the top of the injection cylinder (10). An electric push rod (12) is fixed on the top of the installation frame (9). A connecting block (13) is fixedly connected to the output shaft of the electric push rod (12). The connecting block (13) is fixedly connected to the piston (11).

3. A welding device for touch screen production according to claim 1, characterized in that, The execution mechanism includes a second moving platform (17) and a piezoelectric dispensing valve (18). The second moving platform (17) is fixed on the top of the soldering table (1). The piezoelectric dispensing valve (18) is fixed at the free end of the second moving platform (17).

4. A welding device for touch screen production according to claim 2, characterized in that, The bottom end of the installation frame (9) is fixedly connected with a hanging frame (20). The solder paste thickness acquisition module (6) is fixedly connected to the bottom end of the hanging frame (20). The morphology acquisition module (7) is fixed on the top of the soldering table (1) through a support frame (19). The control module (8) is fixed on the third moving platform (21).

5. The welding device for touch screen production according to claim 2, characterized in that, A feed pipe head (14) is installed on the barrel wall of the injection cylinder (10).

6. The welding device for touch screen production according to claim 2, characterized in that, A heater (15) is installed at a position close to the bottom end of the barrel wall of the injection cylinder (10). A button (16) is arranged on the side of the heater (15).

7. A welding device for touch screen production according to claim 3, characterized in that, The execution mechanism further includes a laser power regulator arranged in the soldering gun (4).

8. A welding device for touch screen production according to claim 1, characterized in that, The control logic of the control module (8) for the working state of the execution mechanism is as follows: First, during the process of solder paste coating, the thickness and morphology of the solder paste after coating are detected; Second, the control module (8) receives the thickness and morphology data information in real time and calculates the evaluation coefficient; Third, when K≥0.8, it is judged as qualified. When K<0.7, tin replenishment is triggered. When 0.7≤K<0.8, it enters the re-inspection process.

9. The welding device for touch screen production according to claim 8, characterized in that, The calculation formula of the evaluation coefficient K is: where α, β, γ: weights of thickness parameters, weights of coverage rate, coefficient of uniformity penalty term, T avg : average thickness of solder paste coating, T std : standard thickness value, A: actual coverage rate of pad, A ideal : ideal coverage rate, standard deviation of thickness.

10. A welding device for touch screen production according to claim 9, characterized in that, The average thickness T of the solder paste coating avg is the arithmetic mean of the thicknesses at multiple measurement points actually detected, and the calculation formula is: where, T i is the actual solder paste coating thickness at the i-th measurement point.

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