Laser marking method and marking device

Abstract

The application relates to the technical field of industrial material processing, in particular to a laser marking method and a marking device, which comprises the following steps: running marking software in the marking device, and importing a marking file into the marking software; placing a product to be marked on a marking platform of the marking device; and marking the product to be marked by using a green femtosecond laser based on the marking file; wherein the product to be marked is composed of aromatic polycarbonate and UV paint, the pulse width of the laser emitted by the green femtosecond laser is 400 fs, and the wavelength is 515 nm. Since the green femtosecond laser is used to mark the material, compared with the existing marking method, the marking product processed by the marking method provided by the application is clearly visible after marking, does not turn yellow, has high contrast, the surface layer is not damaged, and has no hand feeling when touched, so that the quality of the marking product is improved.

Description

Technical Field

[0001] This invention relates to the field of industrial material processing technology, and in particular to a laser marking method and marking equipment. Background Technology

[0002] Currently, research has found that among various industrial materials, aromatic polycarbonates, which belong to the polycarbonate branch, have the characteristics of high transparency, light weight, impact resistance, sound insulation, heat insulation, flame retardancy, and aging resistance. They are a high-tech, high-performance, energy-saving and environmentally friendly plastic material, and are therefore widely used in industrial production. Manufacturers often need to mark the above-mentioned aromatic polycarbonates.

[0003] Because aromatic polycarbonate has a UV coating on its surface, this coating can affect the marking effect of the laser on the material. Using a conventional nanosecond laser for marking can result in unclear marks, or even cause the UV layer to bubble and break, and turn yellow, thus leading to lower product quality.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a laser marking method and marking equipment, which aims to solve the technical problem of low product quality produced by conventional laser marking methods in the prior art.

[0006] To achieve the above objectives, the present invention provides a laser marking method, the method comprising the following steps:

[0007] Run the marking software in the marking equipment, and import the marking image file through the marking software;

[0008] Place the product to be marked on the marking platform of the marking equipment;

[0009] Based on the marking image, a green femtosecond laser is used to mark the product to be marked;

[0010] The product to be marked is composed of aromatic polycarbonate and UV paint, and the pulse width of the laser emitted by the green femtosecond laser is 400 fs and the wavelength is 515 nm.

[0011] Optionally, before running the marking software in the marking equipment and importing the marking drawing file through the marking software, the method further includes:

[0012] Turn on the main switch, chiller switch, laser switch, industrial computer switch, and electrical control box switch of the marking equipment in sequence;

[0013] When the indicator light of the marking device is lit and is in a preset color, the steps of running the marking software in the marking device and importing the marking image file through the marking software are executed.

[0014] Optionally, placing the product to be marked on the marking platform of the marking equipment includes:

[0015] Determine whether the marking device is in a ready-to-mark state;

[0016] If so, the product QR code of the product to be labeled is scanned with a barcode scanner, and the product production information contained in the product QR code is recorded.

[0017] If the product production information matches the preset production information, the product to be marked is placed on the marking platform of the marking equipment.

[0018] Optionally, after placing the product to be marked on the marking platform of the marking equipment, the method further includes:

[0019] The target precision value of the product to be marked is compared with a preset threshold.

[0020] Based on the comparison results, the position of the product to be marked is adjusted so that the marking area of ​​the product to be marked is within the marking range of the marking equipment.

[0021] Optionally, adjusting the position of the product to be marked based on the comparison results includes:

[0022] If the target accuracy is less than or equal to the preset threshold, the position of the product to be marked is adjusted by CCD positioning.

[0023] If the target accuracy is greater than a preset threshold, the position of the product to be marked is adjusted using a positioning fixture.

[0024] Optionally, marking the product to be marked using a green femtosecond laser based on the marking image includes:

[0025] The marking software converts the marking image into a laser path diagram, which is used to indicate the propagation path of the laser emitted by the green femtosecond laser in the marking equipment.

[0026] The green femtosecond laser is controlled to mark the product to be marked according to the laser path diagram.

[0027] Optionally, controlling the green femtosecond laser to mark the product to be marked according to the laser path diagram includes:

[0028] The green femtosecond laser is controlled according to the laser path diagram, and the propagation direction of the laser emitted by the green femtosecond laser is changed by a reflector so that the laser propagates into the galvanometer.

[0029] The laser's movement direction is controlled by the galvanometer, and the laser is focused using a field lens;

[0030] The focused laser is used to mark the product to be marked in the direction of movement controlled by the galvanometer.

[0031] The galvanometer has an aperture of 10mm and a scanning speed of less than 10,000mm / s, while the field lens has a focal length of 160mm and a marking range of 110mm.

[0032] Optionally, the format of the marking image file is any one of DXF, DWG, or PLT.

[0033] In addition, the present invention also provides a marking device, the marking device comprising: a green femtosecond laser and a marking platform;

[0034] The marking platform is equipped with a dual XY axis module, a Z axis module, a reflector mount, a vision component, a galvanometer, and a field lens;

[0035] The moving speed of the dual XY axis module is less than 1000 mm / s, and it is used to control the movement of the marking platform in the X and Y directions.

[0036] The Z-axis module moves at a speed of less than 100 mm / s and is used for the movement of the marking platform in the Z direction.

[0037] The reflector mount contains a reflector used to change the propagation path of the laser emitted by the green femtosecond laser.

[0038] The vision component is used to locate and target the product to be marked.

[0039] Optionally, the green femtosecond laser has a power of 28.2 mW and an energy of 3.2 uJ.

[0040] This invention involves running marking software in a marking device and importing marking images into the software; placing the product to be marked on the marking platform of the marking device; and using a green femtosecond laser to mark the product based on the marking image. The product to be marked is composed of aromatic polycarbonate and UV paint, and the green femtosecond laser emits a laser with a pulse width of 400 fs and a wavelength of 515 nm. Because this invention uses a green femtosecond laser to mark the material, compared to existing marking methods, the marked products produced by this invention have clearly visible markings that do not yellow, have high contrast, and do not damage the surface. They also have a smooth, tactile feel, thus improving the quality of the marked products. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the first embodiment of the laser marking method of the present invention;

[0042] Figure 2 This is a flowchart illustrating the second embodiment of the laser marking method of the present invention;

[0043] Figure 3 This is a flowchart illustrating the third embodiment of the laser marking method of the present invention;

[0044] Figure 4 This is a schematic diagram of the marking equipment of the present invention.

[0045] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0047] This invention provides a laser marking method, as described in the following embodiments. Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the laser marking method of the present invention.

[0048] In this embodiment, the laser marking method includes the following steps:

[0049] Step S10: Run the marking software in the marking equipment and import the marking image file through the marking software.

[0050] It should be noted that the above-mentioned marking equipment may include accessories such as laser, laser path map, reflector, dual XY module, vision component, barcode scanner, Z-axis module, scanning head, field lens, reflector mount, and vision path map.

[0051] It should be understood that the format of the above-mentioned marking image file can be any of DXF, DWG, or PLT, and this embodiment does not limit it.

[0052] Understandably, the aforementioned marking software is a preset software built into the aforementioned marking equipment. The marking equipment parameters, such as the wavelength of the laser, the aperture of the scanning head, and the focal length of the field lens, can be set through the marking software.

[0053] Step S20: Place the product to be marked on the marking platform of the marking equipment.

[0054] It should be noted that the aforementioned product to be marked consists of aromatic polycarbonate and UV (ultraviolet curing coating) paint. Aromatic polycarbonate is a type of polycarbonate. Polycarbonate is a high-molecular polymer containing carbonate groups in its molecular chain, and can be classified into aliphatic, aromatic, and aliphatic-aromatic types based on the structure of the ester groups. The lower mechanical properties of aliphatic and aliphatic-aromatic polycarbonates limit their application in engineering plastics. Only aromatic polycarbonate has achieved industrialized production, possessing characteristics such as high transparency, light weight, impact resistance, sound insulation, heat insulation, flame retardancy, and aging resistance. It is a high-tech, high-performance, energy-saving, and environmentally friendly plastic material. The aforementioned UV paint is a layer of material adhered to the surface of the aromatic polycarbonate, and it can rapidly cure into a film within seconds under ultraviolet light irradiation.

[0055] It should be understood that the aforementioned marking platform is one that can keep the product to be marked horizontally.

[0056] In practice, to avoid contamination of the marking area of ​​the product to be marked, the product can be placed on the marking platform of the marking equipment by using mechanized equipment (such as robotic arms or clamps).

[0057] Step S30: Based on the marking image, use a green femtosecond laser to mark the product to be marked.

[0058] It should be noted that the pulse width of the laser emitted by the aforementioned green femtosecond laser can be 400 fs and the wavelength can be 515 nm.

[0059] It should be understood that the area to be marked on the product can be exposed to the marking range of the marking equipment first, and then the green femtosecond laser can be controlled by the marking software to mark the product.

[0060] Furthermore, to ensure that the marking equipment starts marking work under normal operating conditions, thereby avoiding product scrapping due to the use of abnormal equipment for marking work, the following steps may be included before step S10:

[0061] Step S01: Turn on the main switch of the marking equipment, the chiller switch, the laser switch, the industrial control computer switch, and the electrical control box switch in sequence.

[0062] It should be noted that the above-mentioned chiller switch is used to control the opening or closing of the chiller equipment. The chiller equipment is a cooling water device that can provide constant temperature, constant flow and constant pressure. The chiller equipment can be a screw chiller unit, a scroll chiller unit or a centrifugal chiller unit. This embodiment does not limit it.

[0063] Step S02: When the indicator light of the marking device is lit and is a preset color, execute the step of running the marking software in the marking device and importing the marking image file through the marking software.

[0064] It should be understood that the colors of the indicator lights on the marking equipment can be predefined, for example, green represents normal operation of the marking equipment, and red represents abnormal operation. In actual production, when the indicator light on the marking equipment is lit and green, the steps of running the marking software on the marking equipment and importing the marking image file through the software can be executed. Of course, the above description of preset colors is for illustrative purposes only and not for limitation. Other preset colors that can distinguish between normal and abnormal states of the marking equipment are also applicable to this embodiment, and will not be elaborated here.

[0065] This embodiment involves running marking software in a marking device and importing marking images into the software. The product to be marked is placed on the marking platform of the marking device. Based on the marking images, a green femtosecond laser is used to mark the product. The product to be marked is composed of aromatic polycarbonate and UV paint. The pulse width of the laser emitted by the green femtosecond laser is 400 fs, and the wavelength is 515 nm. Because this embodiment uses a green femtosecond laser to mark the material, compared with existing marking methods, the marked product produced by this method is clearly visible, does not yellow, has high contrast, and the surface is not damaged. It also has a smooth, tactile feel, thus improving the quality of the marked product.

[0066] refer to Figure 2 , Figure 2 This is a flowchart illustrating the second embodiment of the laser marking method of the present invention.

[0067] To ensure that the product information of the product to be marked is consistent with the preset production information, thereby avoiding marking errors, in this embodiment, the step of placing the product to be marked on the marking platform of the marking equipment may include:

[0068] Step S21: Determine whether the marking device is in a state of waiting to be marked.

[0069] It should be understood that whether the marking equipment is in a ready-to-mark state can be determined by combining the indicator light color of the marking equipment with the running status of the marking software. For example, when the indicator light color is the preset color and the marking software is running normally, it can be determined that the marking equipment is in a ready-to-mark state.

[0070] Step S22: If so, scan the product QR code of the product to be marked using a barcode scanner and record the product production information contained in the product QR code.

[0071] Understandably, the product QR codes contain product manufacturing information for the products to be tagged, such as product batch, product shelf life, and product requirements.

[0072] Step S23: If the product production information is consistent with the preset production information, then place the product to be marked on the marking platform of the marking equipment.

[0073] In practice, if the current product production information is consistent with the preset production information, it means that the product to be marked can be marked at this time, and the product to be marked can be placed on the marking platform of the marking equipment.

[0074] Furthermore, to improve the marking accuracy of the product to be marked, after the step of placing the product to be marked on the marking platform of the marking equipment, the following may also be included:

[0075] Step S24: Compare the target accuracy value of the product to be marked with a preset threshold.

[0076] It should be understood that different products may have different requirements for marking accuracy. Therefore, a preset threshold can be set according to the target accuracy of the product, and the target accuracy value of the product to be marked can be compared with the preset threshold.

[0077] Step S25: Adjust the position of the product to be marked based on the comparison results so that the marking area of ​​the product to be marked is within the marking range of the marking equipment.

[0078] It should be understood that in actual marking operations, the marking area of ​​the product to be marked needs to be within the marking range of the marking equipment; otherwise, the produced marked products will be scrapped due to poor positional accuracy. Therefore, by comparing the target accuracy value of the product to be marked with a preset threshold, different methods can be adopted to adjust the position of the product to be marked.

[0079] Furthermore, in order to adopt corresponding position adjustment methods for products with different precision levels, thereby improving the efficiency of the position adjustment step, in this embodiment, step S25 may further include:

[0080] Step S251: If the target accuracy is less than or equal to a preset threshold, the position of the product to be marked is adjusted by CCD positioning.

[0081] It should be understood that when the target accuracy is less than or equal to the preset threshold, it means that the target accuracy of the product to be marked is relatively high. Therefore, the position of the product to be marked can be adjusted by using the CCD (Charge-coupled Device) positioning method, which has higher positioning accuracy but a relatively longer positioning time.

[0082] Step S252: If the target accuracy is greater than the preset threshold, the position of the product to be marked is adjusted by the positioning fixture.

[0083] It should be understood that when the target accuracy is greater than the preset threshold, it means that the target accuracy of the product to be marked is relatively low. Therefore, the position of the product to be marked can be adjusted by using a positioning fixture method with lower accuracy but shorter positioning time.

[0084] This embodiment determines whether the marking equipment is in a marking-ready state. If so, it scans the product QR code of the product to be marked using a barcode scanner and records the product production information contained in the QR code. If the product production information matches the preset production information, the product to be marked is placed on the marking platform of the marking equipment. The target precision value of the product to be marked is compared with a preset threshold. Based on the comparison result, the position of the product to be marked is adjusted so that the marking area of ​​the product to be marked is within the marking range of the marking equipment. If the target precision is less than or equal to the preset threshold, the position of the product to be marked is adjusted using CCD positioning; if the target precision is greater than the preset threshold, the position of the product to be marked is adjusted using a positioning fixture. Since this embodiment adopts corresponding position adjustment methods for products with different precisions, compared with the prior art which only uses one positioning method to position the product to be marked, the above method of this embodiment can improve the work efficiency of the position adjustment step.

[0085] refer to Figure 3 , Figure 3 This is a flowchart illustrating the third embodiment of the laser marking method of the present invention.

[0086] To enable more precise control of the green femtosecond laser, in this embodiment, the step of marking the product to be marked using a green femtosecond laser based on the marking pattern can include:

[0087] Step S301: The marking image file is converted into a laser path diagram by the marking software. The laser path diagram is used to indicate the propagation path of the laser emitted by the green femtosecond laser in the marking equipment.

[0088] Step S302: Control the green femtosecond laser to mark the product to be marked according to the laser path diagram.

[0089] In practical implementation, since the pulse width emitted by a green femtosecond laser is much smaller than the thermal diffusion time and the electron-phonon coupling time in the material, it means that during the entire continuous laser irradiation time, only the excitation and energy storage process of electrons absorbing incident photons needs to be considered, while the electron temperature can be completely ignored due to the cooling of radiated phonons and the thermal diffusion process. The interaction between laser and matter is actually mainly manifested as the process of stimulated electron absorption and energy storage, fundamentally avoiding the transfer and conversion of energy, as well as the presence and effects of thermal energy and thermal diffusion. Therefore, when the laser pulse is incident, the energy generated by the absorption of photons will rapidly accumulate in the only nanometer-thick absorption layer, instantly generating electrons with a temperature value far exceeding the melting temperature, or even the vaporization temperature, of the material to be marked. This causes the material to be marked to directly transform from a solid to a gaseous state, forming a high-density, ultra-hot, and high-pressure plasma state on the laser-irradiated surface of the material to be marked, realizing non-thermal melting laser processing, thereby performing marking work on the product to be marked.

[0090] Furthermore, in order to more accurately control the laser emitted by the green femtosecond laser, in this embodiment, step 302 above may include:

[0091] Step S3021: Control the green femtosecond laser according to the laser path diagram, and change the propagation direction of the laser emitted by the green femtosecond laser through a reflector so that the laser propagates into the galvanometer.

[0092] It should be noted that the above-mentioned reflector can be 45°, that is, the incident angle of the laser on the reflector is 45°.

[0093] Step S3022: Control the movement direction of the laser using the galvanometer and focus the laser using a field lens.

[0094] It should be noted that the aforementioned galvanometer, also known as the scanning head, contains two motors with reflectors to control the movement of the laser in the X and Y directions, thereby enabling the processing of complex patterns. The galvanometer's aperture can be 10mm, and the scanning speed is less than 10,000mm / s.

[0095] Understandably, the focal length of the aforementioned field lens can be 160mm, and the marking range can be 110mm.

[0096] Step S3023: Use the focused laser to mark the product to be marked in the direction controlled by the galvanometer.

[0097] This embodiment converts the marking image into a laser path diagram using marking software. The laser path diagram indicates the propagation path of the laser emitted by the green femtosecond laser within the marking equipment. The green femtosecond laser is controlled according to the laser path diagram, and its propagation direction is altered by a reflector to guide it into the galvanometer. The galvanometer controls the laser's movement direction, and a field lens focuses the laser. The focused laser is then used to mark the product according to the movement direction controlled by the galvanometer. Because this invention intervenes in laser propagation by combining a reflector and a galvanometer, and uses a field lens to focus the laser, the energy of the laser ultimately acting on the product to be marked is more uniform, and the spot is more focused, thereby improving the marking quality.

[0098] In addition, such as Figure 4 As shown, Figure 4 This is a schematic diagram of the marking equipment of the present invention.

[0099] This invention also proposes a marking device that can be applied to the laser marking method described above. The marking device includes a green femtosecond laser and a marking platform. The marking platform is equipped with a dual XY-axis module, a Z-axis module, a CCD reflector mount, a 3x reflector mount, a vision component, a barcode scanner, a galvanometer (or scanning head), a field lens, a laser path map, and a vision path map. The dual XY-axis module moves at a speed of less than 1000 mm / s and is used to control the movement of the marking platform in the X and Y directions. The Z-axis module moves at a speed of less than 100 mm / s and is used to move the marking platform in the Z direction. The reflector mount contains a reflector used to change the propagation path of the laser emitted by the green femtosecond laser. The vision component is used for positioning and targeting the product to be marked. The green femtosecond laser has a power of 28.2 mW and an energy of 3.2 uJ.

[0100] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0101] The sequence numbers of the above embodiments of the present invention are merely for description and do not represent the superiority or inferiority of the embodiments. Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory / random access memory, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0102] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A laser marking method, characterized in that, The method includes the following steps: Run the marking software in the marking equipment, and import the marking image file through the marking software; Place the product to be marked on the marking platform of the marking equipment; The target precision value of the product to be marked is compared with a preset threshold. Based on the comparison results, the position of the product to be marked is adjusted so that the marking area of ​​the product to be marked is within the marking range of the marking equipment. Based on the marking image, a green femtosecond laser is used to mark the product to be marked; The product to be marked is composed of aromatic polycarbonate and UV paint, and the pulse width of the laser emitted by the green femtosecond laser is 400 fs and the wavelength is 515 nm. The adjustment of the position of the product to be marked based on the comparison results includes: If the target accuracy is less than or equal to the preset threshold, the position of the product to be marked is adjusted by CCD positioning. If the target accuracy is greater than a preset threshold, the position of the product to be marked is adjusted using a positioning fixture.

2. The laser marking method as described in claim 1, characterized in that, Before running the marking software in the marking equipment and importing the marking image file through the marking software, the process also includes: Turn on the main switch, chiller switch, laser switch, industrial computer switch, and electrical control box switch of the marking equipment in sequence; When the indicator light of the marking device is lit and is in a preset color, the steps of running the marking software in the marking device and importing the marking image file through the marking software are executed.

3. The laser marking method as described in claim 2, characterized in that, Placing the product to be marked on the marking platform of the marking equipment includes: Determine whether the marking device is in a ready-to-mark state; If so, the product QR code of the product to be labeled is scanned with a barcode scanner, and the product production information contained in the product QR code is recorded. If the product production information matches the preset production information, the product to be marked is placed on the marking platform of the marking equipment.

4. The laser marking method as described in claim 1, characterized in that, The step of marking the product to be marked using a green femtosecond laser based on the marking image file includes: The marking software converts the marking image into a laser path diagram, which is used to indicate the propagation path of the laser emitted by the green femtosecond laser in the marking equipment. The green femtosecond laser is controlled to mark the product to be marked according to the laser path diagram.

5. The laser marking method as described in claim 4, characterized in that, The step of controlling the green femtosecond laser to mark the product to be marked according to the laser path diagram includes: The green femtosecond laser is controlled according to the laser path diagram, and the propagation direction of the laser emitted by the green femtosecond laser is changed by a reflector so that the laser propagates into the galvanometer. The laser's movement direction is controlled by the galvanometer, and the laser is focused using a field lens; The focused laser is used to mark the product to be marked in the direction of movement controlled by the galvanometer. The galvanometer has an aperture of 10mm and a scanning speed of less than 10,000mm / s, while the field lens has a focal length of 160mm and a marking range of 110mm.

6. The laser marking method as described in claim 1, characterized in that, The format of the marking image file can be any one of DXF, DWG, or PLT.

Images