Transparent plastic welding method, device and computer readable storage medium

Abstract

The present invention discloses a transparent plastic welding method, device and computer-readable storage medium, the method comprising: placing the transparent plastic on a welding platform; detecting the bonding seam of the transparent material, and determining the area where the bonding seam is located as a target welding area; controlling the laser welding equipment to form a Bessel beam in the target welding area to complete the welding of the transparent material. The present invention improves the welding quality of the transparent material.

Description

Technical Field

[0001] The present invention relates to the technical field of laser welding, and in particular to a transparent plastic welding method, device and computer-readable storage medium. Background Art

[0002] For the welding process of plastic end faces, the existing process requires the material end faces of the plastic to be welded to be wedge-shaped in order to increase the angle between the laser incident direction and the welded end face. However, after the wedge-shaped end face is formed, the wedge-shaped end face must be pressed well, which increases the complexity of the pressing fixture and makes it difficult to ensure the welding quality. Summary of the invention

[0003] The embodiments of the present invention provide a transparent plastic welding method, a device and a computer-readable storage medium, aiming to solve the technical problem of how to improve the welding quality of transparent plastic.

[0004] An embodiment of the present invention provides a transparent plastic welding method, the transparent plastic welding method comprising the following steps:

[0005] Place the clear plastic on the welding platform;

[0006] Detecting the bonding seam of the transparent material, and determining the area where the bonding seam is located as the target welding area;

[0007] The laser welding equipment is controlled to form a Bessel beam in the target welding area to complete the welding of the transparent material.

[0008] In one embodiment, the step of controlling the laser welding device to form a Bessel beam in the target welding area includes:

[0009] The laser welding equipment is controlled to emit Gaussian light, wherein the Gaussian light is focused at the target welding area to form the Bessel beam.

[0010] In one embodiment, the step of controlling the laser welding equipment to emit Gaussian light comprises:

[0011] Adjusting the axicon lens, the first focusing mirror and the second focusing mirror in the laser welding device according to the position of the target welding area;

[0012] The Gaussian light source in the laser welding equipment is turned on to emit Gaussian light, wherein when the Gaussian light is incident on the axicon lens, the first focusing mirror and the second focusing mirror in sequence, it is focused into the Bessel beam at the target welding area.

[0013] In one embodiment, the step of controlling the laser welding equipment to emit Gaussian light comprises:

[0014] The laser welding equipment is controlled to emit the Gaussian light with a wavelength of 1900nm to 2100nm.

[0015] In one embodiment, the width of the laminating seam is less than or equal to 20 mm.

[0016] In one embodiment, the step of controlling the laser welding equipment to emit Gaussian light comprises:

[0017] The laser welding equipment is controlled to emit Gaussian light in a preset direction, where the preset direction is parallel to the bonding seam.

[0018] In one embodiment, the step of placing the transparent plastic on the welding platform comprises:

[0019] The transparent plastic is fixed on the welding platform by a pressing jig.

[0020] In one embodiment, the transparent plastics have the same light absorption rate.

[0021] An embodiment of the present invention further provides a transparent plastic welding device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the various steps of the transparent plastic welding method described above when executing the computer program.

[0022] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, each step of the transparent plastic welding method described above is implemented.

[0023] In the technical solution of this embodiment, the transparent plastic welding device places the transparent plastic on the welding platform; detects the bonding seam of the transparent material, and determines the area where the bonding seam is located as the target welding area; controls the laser welding equipment to form a Bessel beam in the target welding area to complete the welding of the transparent material. Since the transparent plastic welding device controls the laser welding equipment to form a Bessel beam in the target welding area, and the characteristics of the Bessel beam determine that the focused beam has a longer focal depth, and the focused spot diameter is smaller, and the weld width is smaller, therefore, thicker transparent materials can be welded without wedge angle pretreatment, reducing the complexity of the pressing jig, thereby improving the welding quality of the transparent material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the hardware architecture of the transparent plastic welding device involved in the embodiment of the present invention;

[0026] Figure 2 It is a schematic flow chart of a first embodiment of a transparent plastic welding method of the present invention;

[0027] Figure 3 A reference diagram of a first embodiment of a transparent plastic welding method according to the present invention;

[0028] Figure 4 A reference diagram of a first embodiment of a transparent plastic welding method according to the present invention;

[0029] Figure 5 A reference diagram of a first embodiment of a transparent plastic welding method according to the present invention;

[0030] Figure 6 A reference diagram of a first embodiment of a transparent plastic welding method according to the present invention;

[0031] Figure 7 It is a schematic flow chart of a second embodiment of a transparent plastic welding method of the present invention;

[0032] Figure 8 It is a schematic flow chart of a third embodiment of a transparent plastic welding method of the present invention;

[0033] Fig. 9 A reference diagram of a third embodiment of a transparent plastic welding method according to the present invention;

[0034] Fig.10 A reference diagram of a third embodiment of a transparent plastic welding method according to the present invention;

[0035] Fig.11 This is a reference diagram of a third embodiment of the transparent plastic welding method of the present invention. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solution, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0037] The main solution of the present invention is: the transparent plastic welding device places the transparent plastic on a welding platform; detects the bonding seam of the transparent material, and determines the area where the bonding seam is located as the target welding area; controls the laser welding equipment to form a Bessel beam in the target welding area to complete the welding of the transparent material.

[0038] Since the transparent plastic welding device controls the laser welding equipment to form a Bessel beam in the target welding area, and the characteristics of the Bessel beam determine that the focused beam has a longer focal depth, and the focused spot diameter is smaller, the weld width is smaller, therefore, thicker transparent materials can be welded without wedge angle pretreatment, reducing the complexity of the pressing jig, thereby improving the welding quality of transparent materials.

[0039] As an implementation method, the transparent plastic welding device can be as follows Figure 1 .

[0040] The embodiment of the present invention relates to a transparent plastic welding device, which includes: a processor 101, such as a CPU, a memory 102, and a communication bus 103. The communication bus 103 is used to realize connection and communication between these components.

[0041] The memory 102 may be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. Figure 1 , the memory 103 as a computer-readable storage medium may include a detection program; and the processor 101 may be used to call the detection program stored in the memory 102 and perform the following operations:

[0042] Place the clear plastic on the welding platform;

[0043] Detecting the bonding seam of the transparent material, and determining the area where the bonding seam is located as the target welding area;

[0044] The laser welding equipment is controlled to form a Bessel beam in the target welding area to complete the welding of the transparent material.

[0045] In one embodiment, the processor 101 may be used to call the detection program stored in the memory 102 and perform the following operations:

[0046] The laser welding equipment is controlled to emit Gaussian light, wherein the Gaussian light is focused at the target welding area to form the Bessel beam.

[0047] In one embodiment, the processor 101 may be used to call the detection program stored in the memory 102 and perform the following operations:

[0048] Adjusting the axicon lens, the first focusing mirror and the second focusing mirror in the laser welding device according to the position of the target welding area;

[0049] The Gaussian light source in the laser welding equipment is turned on to emit Gaussian light, wherein when the Gaussian light is incident on the axicon lens, the first focusing mirror and the second focusing mirror in sequence, it is focused into the Bessel beam at the target welding area.

[0050] In one embodiment, the processor 101 may be used to call the detection program stored in the memory 102 and perform the following operations:

[0051] The laser welding equipment is controlled to emit the Gaussian light with a wavelength of 1900nm to 2100nm.

[0052] In one embodiment, the processor 101 may be used to call the detection program stored in the memory 102 and perform the following operations:

[0053] The laser welding equipment is controlled to emit Gaussian light in a preset direction, where the preset direction is parallel to the bonding seam.

[0054] In one embodiment, the processor 101 may be used to call the detection program stored in the memory 102 and perform the following operations:

[0055] The transparent plastic is fixed on the welding platform by a pressing jig.

[0056] In the technical solution of this embodiment, the transparent plastic welding device places the transparent plastic on the welding platform; detects the bonding seam of the transparent material, and determines the area where the bonding seam is located as the target welding area; controls the laser welding equipment to form a Bessel beam in the target welding area to complete the welding of the transparent material. Since the transparent plastic welding device controls the laser welding equipment to form a Bessel beam in the target welding area, and the characteristics of the Bessel beam determine that the focused beam has a longer focal depth, and the focused spot diameter is smaller, and the weld width is smaller, therefore, thicker transparent materials can be welded without wedge angle pretreatment, reducing the complexity of the pressing jig, thereby improving the welding quality of the transparent material.

[0057] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0058] Reference Figure 2 , Figure 2 The first embodiment of the transparent plastic welding method of the present invention comprises the following steps:

[0059] Step S10, placing the transparent plastic on the welding platform.

[0060] Laser equipment can be divided into three categories: laser marking machine, laser welding machine, and laser cutting machine. Laser marking machines include semiconductor laser marking machines, CO2 laser marking machines, fiber laser marking machines, and ultraviolet laser marking machines; laser welding machines currently include YAG laser automatic welding machines and fiber transmission automatic laser welding machines; laser cutting machines include YAG laser cutting machines and fiber laser cutting machines. This embodiment prefers laser welding machines. Laser welding can be achieved using continuous or pulsed laser beams. The principles of laser welding can be divided into heat conduction welding and laser deep penetration welding. The power density is less than 10^10W / cm 2 It is heat conduction welding, in which the melting depth is shallow and the welding speed is slow; the power density is greater than 10^10W / cm 2When the metal surface is heated, it is sunken into a "hole", forming a deep fusion weld, which has the characteristics of fast welding speed and large depth-to-width ratio. The principle of heat conduction laser welding is: the laser radiation heats the surface to be processed, and the surface heat diffuses to the inside through heat conduction. By controlling the laser parameters such as the width, energy, peak power and repetition frequency of the laser pulse, the workpiece is melted to form a specific molten pool. The laser welding machine used for gear welding and metallurgical thin plate welding mainly involves laser deep fusion welding. Laser deep fusion welding generally uses a continuous laser beam to complete the connection of materials. Its metallurgical physical process is very similar to electron beam welding, that is, the energy conversion mechanism is completed through a "key-hole" structure. Under sufficiently high power density laser irradiation, the material evaporates and forms a keyhole. This small hole filled with steam is like a black body, absorbing almost all the energy of the incident beam. The equilibrium temperature in the cavity is about 2500 degrees Celsius. The heat is transferred from the outer wall of the high-temperature cavity to melt the metal surrounding the cavity. The small hole is filled with high-temperature steam generated by the continuous evaporation of the wall material under the irradiation of the light beam. The four walls of the small hole are surrounded by molten metal, and the liquid metal is surrounded by solid materials (in most conventional welding processes and laser conduction welding, the energy is first deposited on the surface of the workpiece and then transmitted to the inside). The liquid flow outside the hole wall and the surface tension of the wall layer are in a dynamic balance with the steam pressure continuously generated in the hole cavity. The light beam continuously enters the small hole, and the material outside the small hole is continuously flowing. As the light beam moves, the small hole is always in a stable state of flow. That is, the small hole and the molten metal surrounding the hole wall move forward with the forward speed of the leading light beam. The molten metal fills the gap left after the small hole is removed and condenses, and the weld is formed. All of the above processes happen so quickly that the welding speed can easily reach several meters per minute.

[0061] The basic principle of plastic welding belongs to the category of hot melt welding, that is, the plastic absorbs part of the energy injected by the laser and converts it into heat energy to achieve the purpose of welding. Therefore, the absorption rate of a certain plastic at different wavelengths, the thickness of the material, and the color and surface texture of the plastic play a vital role in the welding effect. The transmittance of different plastic materials at different wavelengths is as follows: Figure 3 shown.

[0062] In the plastic welding process, the commonly used laser wavelengths are 808nm, 915nm, 976nm, etc. (wavelength range is 800nm-1100nm), and because most plastics have low absorption rates in this band, in order for the laser to successfully melt and weld thermoplastics, it is necessary to increase the absorption rate through additives such as pigments or carbon black. Therefore, the usual practice now is that one component is a transparent plastic and the other is an absorbent plastic (darker in color or with infrared absorbers added). Using this welding method, the laser beam can penetrate the upper layer of transparent plastic and reach the bottom layer of absorbent plastic. The laser can then melt the surface of the absorbent plastic because of heat transfer, and the bottom of the transparent component is also melted. For opaque parts, in fact, beautiful but invisible welds are produced. Common welding processes include lap welding and end face welding such as Figure 4 shown.

[0063] With the continuous acceleration of the development and industrialization of various 2μm thulium-doped fiber lasers, new solutions are brought to plastic welding, especially transparent plastic welding. Figure 3 It can be seen that the absorption rate of most plastic materials to wavelengths of 1900nm-2100nm is between infrared (750nm-1100nm) and CO2 (10.6μm). The absorption rate for materials such as PMMA, PP, PC is between 25%-40%, and for PA6 it can be as high as 70%. Therefore, for plastic materials, lasers with a wavelength of 2.0μm have a better balance between laser energy absorption and energy transmission. By selecting the beam quality and adjusting the focal depth, the beam diameter falling on the upper surface of the workpiece is much larger than the focal spot. When the laser passes through the upper workpiece, due to the large beam diameter, its energy density is not enough to melt the upper workpiece, and the focus of the laser is at the weld. Since the focus has sufficient energy density, and the combined contact surface of the workpiece forms a steep drop in refractive index, it is easy to produce an energy concentration effect, melting the plastic to complete the welding. Figure 5 shown.

[0064] But for Figure 4 and Figure 5 In the plastic end face welding process, the existing welding process requires the end face of the material to be welded to be wedge-shaped. This is to increase the angle between the laser incident direction and the end face to be welded, improve the absorption efficiency of the end face, and achieve the purpose of welding. The specific content is as follows Figure 6 As shown, this not only increases the cost of the welding process, but also seriously affects the welding quality due to the quality of the processing of the wedge end surface. It also increases the complexity of the pressure fixture.

[0065] In this embodiment, the transparent plastic may be a transparent material that has not been subjected to wedge pretreatment, and the welding platform is a platform provided on a transparent plastic welding device for placing the transparent material to be welded.

[0066] Optionally, the transparent plastic is fixed on the welding platform by a pressing jig.

[0067] Step S20, detecting the bonding seam of the transparent material, and determining the area where the bonding seam is located as the target welding area.

[0068] In this embodiment, the fitting seam of the transparent material can be understood as the welding area. It is easy to understand that when there is no requirement for the welding angle, the fitting seam can be made as small as possible, reducing the area of ​​the welding area, reducing the area that needs to be welded, and thus improving the welding quality.

[0069] Step S30, controlling the laser welding equipment to form a Bessel beam in the target welding area to complete the welding of the transparent material.

[0070] In this embodiment, the welding head used by the controlled laser welding equipment is a Bessel welding head, which is combined with a laser light source with a wavelength of 1900nm-2100nm to perform end face direct welding on transparent plastic.

[0071] Optionally, the transparent plastics have the same absorbance. Controlling the absorbance of the transparent plastics to be welded to be the same can prevent the sub-materials to be welded from reacting differently when there are sub-materials with different absorbances in the transparent plastics to be welded, thereby improving the welding quality of the transparent plastics.

[0072] Optionally, welding can be performed using a welding head and a movable XY table, or using a Bessel beam galvanometer.

[0073] In the technical solution of this embodiment, since the welding device of the transparent plastic controls the laser welding equipment to form a Bessel beam in the target welding area, and the characteristics of the Bessel beam determine that the focused beam has a longer focal depth, and the focused spot diameter is smaller, and the weld width is smaller, therefore, thicker transparent materials can be welded without the need for wedge angle pretreatment, thereby reducing the complexity of the pressing jig and improving the welding quality of the transparent material.

[0074] Reference Figure 7 , Figure 7 This is a second embodiment of the transparent plastic welding method of the present invention. Based on the first embodiment, step S30 includes:

[0075] Step S31, controlling the laser welding equipment to emit Gaussian light, wherein the Gaussian light is focused at the target welding area to form the Bessel beam.

[0076] In this embodiment, Gaussian light emitted by the laser welding device can be focused to obtain a Bessel beam.

[0077] Optionally, the laser welding device is controlled to emit the Gaussian light with a wavelength of 1900nm to 2100nm. The Bessel beam combined with the laser source with a wavelength of 1900nm-2100nm can directly weld the end faces of thick (up to 20mm) transparent plastics without the need for wedge surface pretreatment. In addition, the weld seam is narrow, the welding is smooth, the welding efficiency is high, and the welding strength is high.

[0078] Optionally, the width of the laminating seam is less than or equal to 20 mm. Controlling the width of the laminating seam can prevent the poor welding quality caused by a larger laminating seam from occurring.

[0079] In the technical solution of this embodiment, compared with the prior art, when welding the transparent plastic end faces, this embodiment does not need to perform wedge processing on the plastic end faces, which greatly reduces the cost of plastic end face welding and simplifies the welding process. When welding the transparent plastic end faces, this embodiment does not need to adjust the incident angle of the laser and the focus of the laser, thereby greatly improving the welding speed. When welding the transparent plastic end faces, this embodiment uses a Bessel spot for welding, and the welding end faces absorb the laser uniformly, which greatly improves the consistency and quality of the weld and greatly improves the product yield.

[0080] Reference Figure 8 , Figure 8 The third embodiment of the transparent plastic welding method of the present invention is based on any one of the first to second embodiments, and step S31 includes:

[0081] Step S311, adjusting the axicon lens, the first focusing mirror and the second focusing mirror in the laser welding equipment according to the position of the target welding area.

[0082] Step S312, turning on the Gaussian light source in the laser welding equipment to emit Gaussian light, wherein the Gaussian light is sequentially incident on the axicon lens, the first focusing mirror and the second focusing mirror, and is focused into the Bessel beam at the target welding area.

[0083] In this embodiment, the Bessel beam is formed by injecting ordinary Gaussian light into an axicon lens and passing through a lens group (such as Fig. 9 As shown), the Bessel beam formed by focusing the Gaussian beam (as shown Fig.10 As shown in the figure, the wedge angle is usually no more than 30 degrees. Compared with the common Gaussian spot, the Bessel spot beam has the characteristics of small spot diameter and long focal depth.

[0084] In the technical solution of this embodiment, the difference between Bessel beam and ordinary Gaussian spot in welding transparent materials. Ordinary Gaussian incident light, under the condition of ensuring a certain energy density, the focal depth of the focused spot is generally small (generally not more than 1mm). To obtain a longer focal depth, a focusing lens with a longer focal length must be used, which will greatly reduce the energy density. The depth of such spot welding is very limited, and the weld width is wide (such as Fig.11 a), the characteristics of the Bessel beam determine that the focused beam has a long focal depth (can reach 10mm), and the focused spot diameter is small (generally less than 5mm), the weld width is small, so thick transparent materials can be welded without wedge angle pretreatment (such as Fig.11 b) in the above.

[0085] To achieve the above objective, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, each step of the transparent plastic welding method described above is implemented.

[0086] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0087] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0088] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0089] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0090] It should be noted that in the claims, any reference signs placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0091] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0092] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the present invention.

[0093] Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for welding transparent plastics, characterized in that: The transparent plastic welding method comprises the following steps: Place the clear plastic on the welding platform; The step of placing the transparent plastic on the welding platform comprises: fixing the transparent plastic on the welding platform by a pressing jig; Detecting the bonding seam of the transparent material, and determining the area where the bonding seam is located as the target welding area; Controlling the laser welding equipment to form a Bessel beam in the target welding area to complete the welding of the transparent material; The step of controlling the laser welding device to form a Bessel beam in the target welding area includes: controlling the laser welding device to emit Gaussian light, wherein the Gaussian light is focused in the target welding area to form the Bessel beam; The step of controlling the laser welding device to emit Gaussian light comprises: controlling the laser welding device to emit Gaussian light of 1900nm to 2100nm, which can be used to directly weld the end face of transparent plastic with a thickness of less than or equal to 20mm; the width of the bonding seam is less than or equal to 20mm; The step of controlling the laser welding equipment to emit Gaussian light comprises: Adjusting the axicon lens, the first focusing mirror and the second focusing mirror in the laser welding device according to the position of the target welding area; Turning on a Gaussian light source in the laser welding device to emit Gaussian light, wherein when the Gaussian light is incident on the axicon lens, the first focusing mirror, and the second focusing mirror in sequence, it is focused at the target welding area to become the Bessel beam; The step of controlling the laser welding equipment to emit Gaussian light comprises: Controlling the laser welding device to emit Gaussian light in a preset direction, wherein the preset direction is parallel to the bonding seam; The transparent plastics have the same light absorbance.

2. A transparent plastic welding device, characterized in that: The transparent plastic welding device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the transparent plastic welding method as claimed in claim 1 are implemented.

3. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the transparent plastic welding method according to claim 1 are implemented.

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