Laser engraving device for mobile phone case

Abstract

The present invention relates to the field of laser engraving control technology, and in particular to a laser engraving device for a mobile phone case. The device is equipped with a temperature monitoring device for monitoring the temperature of the engraving area of ​​the laser beam on the mobile phone case during the laser engraving process. A power control module is used to analyze the temperature information in the laser beam engraving area on the mobile phone case to obtain temperature diffusivity, and the temperature diffusivity can be used to characterize the degree of adaptation between the material and the laser beam at the current position of the mobile phone case. Further considering the required engraving depth, a power adjustment factor can be obtained, and the initial power is adjusted according to the power adjustment factor. The present invention can avoid the problem of overheating or insufficient engraving of the current material caused by the initial power through adaptive power adjustment.

Description

Technical Field

[0001] The invention relates to the technical field of laser engraving control, and in particular to a laser engraving device for a mobile phone shell. Background Art

[0002] Laser engraving is a commonly used engraving method in the mobile phone case engraving process. For some complex engraving tasks, the engraving depth and engraving speed of each position may be different. Therefore, in the laser engraving task, it is necessary to adaptively set the laser engraving power so that the engraving quality of the mobile phone case meets the quality requirements. However, in the prior art, considering the different materials of mobile phone cases, and that a mobile phone case is made of multiple materials, different materials have different properties such as reflectivity and absorption rate for lasers, which leads to different engraving effects for the same laser power on different materials. If the power is set only considering the engraving task requirements without considering the influence of the mobile phone case material on the laser engraving, the final engraving quality will not meet the quality requirements, and the surface of the mobile phone case will be excessively melted or the marks will be too shallow. Summary of the invention

[0003] In order to solve the technical problem that the power is set by only considering the engraving task requirements without considering the material of the mobile phone case in the prior art, so that the final engraving quality does not meet the quality requirements, the purpose of the present invention is to provide a laser engraving device for a mobile phone case, and the technical solution adopted is as follows:

[0004] The present invention proposes a laser engraving device for a mobile phone case, comprising a laser engraving device body, on which a temperature monitoring device is installed; the temperature monitoring device is used to monitor the temperature of the engraving area of ​​the laser beam on the mobile phone case during the laser engraving process;

[0005] The laser engraving device also includes a power control system, which receives the temperature data transmitted by the temperature monitoring device, and counts the engraving depth of each position on the mobile phone case in this engraving task; at each engraving moment in the laser engraving process, analyzes the temperature distribution in the engraving area to obtain the temperature diffusivity of the engraving area; obtains a power adjustment factor according to the temperature diffusivity and engraving depth at each engraving moment; and adjusts the initial power at the corresponding engraving moment according to the power adjustment factor.

[0006] Furthermore, the method for obtaining the temperature diffusivity includes:

[0007] The average temperature of the engraving area is obtained; the temperature gradient characteristics of each position in the engraving area are obtained, and the average values ​​of the temperature gradient characteristics of all positions are negatively correlated to obtain the initial temperature diffusivity; the product of the initial temperature diffusivity and the average temperature is normalized to obtain the temperature diffusivity.

[0008] Furthermore, the method for acquiring the temperature gradient characteristics includes:

[0009] For each position in the engraving area, the direction from the center point of the engraving area to the position is used as the temperature diffusion direction, the next position of the position in the corresponding temperature diffusion direction is used as the comparison position, and the temperature value difference between the position and the corresponding comparison position is used as the temperature gradient feature.

[0010] Furthermore, the method for obtaining the power adjustment factor includes:

[0011] The average engraving depth of all positions in this engraving task is counted, the depth deviation of the engraving depth at each position is obtained according to the average engraving depth, and the power adjustment factor is obtained according to the depth deviation and the temperature diffusivity.

[0012] Furthermore, the method for obtaining the depth deviation includes:

[0013] The ratio of the average engraving depth to the engraving depth at each position is obtained, and the difference between the ratio and the positive integer 1 is taken as the depth deviation.

[0014] Further, obtaining the power adjustment factor according to the depth deviation and the temperature diffusivity includes:

[0015] The depth deviation is multiplied by the temperature diffusivity, and the value range of the multiplication result is mapped to between -1 and 1 to obtain the power adjustment factor.

[0016] Further, the adjusting the initial power at the corresponding engraving moment according to the power adjustment factor includes:

[0017] The difference between the positive integer 1 and the power adjustment factor is used as the adjustment coefficient, and the adjustment coefficient is multiplied by the initial power at the corresponding engraving moment to obtain the adjusted power.

[0018] Furthermore, before this engraving task, the initial power at the corresponding position is set according to the engraving depth, engraving area and engraving speed required at each position.

[0019] Furthermore, the engraving depth required for each position, the engraving area, and the preset proportional coefficient of the engraving speed are multiplied to obtain the initial power.

[0020] Furthermore, the temperature monitoring device is an infrared camera.

[0021] The present invention has the following beneficial effects:

[0022] The embodiment of the present invention takes into account that different materials have different feedbacks on the laser beam in laser engraving, and laser engraving mainly relies on the temperature of the laser beam. For materials with good thermal conductivity and compatible with laser engraving, engraving does not require excessive power. Therefore, the temperature information in the laser beam engraving area on the mobile phone case is analyzed to obtain temperature diffusivity, which can be used to characterize the degree of compatibility between the material and the laser beam at the current position of the mobile phone case. Further considering the required engraving depth, the power adjustment factor can be obtained. Adjusting the initial power according to the power adjustment factor can avoid the problem of overheating or insufficient engraving of the current material caused by the initial power. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are 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.

[0024] Figure 1 A flow chart of a control method for a power control system in a laser engraving device for a mobile phone case provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of a laser engraving device for a mobile phone case proposed by the present invention in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0026] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0027] The laser engraving device for a mobile phone case provided in an embodiment of the present invention includes a laser engraving device body. The laser engraving device body may be a conventional laser engraving device, for example, it may include a transparent glass cover, a laser head guide slide bar, a side support platform, a laser head, a baffle, a mobile phone case clamping block, a rotating push rod, a support rod, a baffle support frame, a base, and a base support frame. It should be noted that the functions of each device in the conventional mobile phone case laser engraving device are well known to those skilled in the art and will not be repeated here. A temperature monitoring device is also installed on the laser engraving device body of the laser engraving device for a mobile phone case provided in an embodiment of the present invention, which is used to monitor the temperature of the engraving area of ​​the laser beam on the mobile phone case during the laser engraving process. In one embodiment of the present invention, the temperature monitoring device is an infrared camera, which can be installed on the top of the laser engraving device body, and the temperature monitoring device collects temperature information at each position on the mobile phone case from a top-down perspective. It should be noted that the infrared camera can collect thermal images of the mobile phone case, and in the thermal image, the thermal value of each position on the mobile phone case can be regarded as the corresponding temperature value. Because the embodiment of the present invention requires real-time regulation of the engraving power, the sampling frequency of the temperature monitoring device should be large enough to enable timely adjustment of the engraving power. In the embodiment of the present invention, temperature data is collected every 0.05s, that is, every 0.05 seconds is used as a sampling moment.

[0028] Preferably, in one embodiment of the present invention, taking into account that different engraving tasks have different engraving requirements, the engraving requirements include engraving depth, engraving area, and engraving speed. Therefore, before engraving, it is necessary to set the initial power at the corresponding position according to the engraving depth, engraving area, and engraving speed required for each position on the mobile phone case.

[0029] Furthermore, in an embodiment of the present invention, the engraving depth required for each position, the engraving area, and the preset proportional coefficient of the engraving speed are directly multiplied to obtain the initial power. The proportional coefficient can be obtained by data fitting. In an embodiment of the present invention, the least squares method is fitted according to known data, and then the proportional coefficient is solved to obtain the proportional coefficient. In other embodiments of the present invention, a specific proportional coefficient can also be set according to the experience of the engraving process, which is not limited or elaborated here.

[0030] The laser engraving device for mobile phone cases in the embodiment of the present invention also includes a power control system. The power control system can adaptively adjust the power during engraving by counting the requirements of the engraving task and the temperature data during engraving, so that the material during engraving and the laser output power match each other, thereby improving the engraving quality of the mobile phone case. Figure 1 , which shows a flow chart of a control method of a power control system in a laser engraving device for a mobile phone case, the method comprising:

[0031] Step S1: receiving temperature data transmitted by a temperature monitoring device, and counting the engraving depth of each position on the mobile phone case in this engraving task.

[0032] Before the laser engraving device engraves the phone case, the initial power of each position on the phone case has been set. However, because there may be mixed materials on the phone case, the set initial power is not applicable to certain materials, so the power needs to be adjusted. For the engraving area on the phone case, the temperature data in the area can clearly reflect the characteristics of the material. Therefore, the power control system needs to receive the temperature data transmitted by the temperature monitoring device, and needs to count the engraving depth required for each position on the phone case in this engraving task for subsequent data processing.

[0033] It should be noted that in the embodiment of the present invention, since the area of ​​the laser beam is fixed, when performing an engraving task, the engraving area is the area on the mobile phone case where the laser beam irradiates. The temperature information of the engraving area can be obtained by corresponding to the thermal map.

[0034] Step S2: At each engraving moment during the laser engraving process, the temperature distribution in the engraving area is analyzed to obtain the temperature diffusivity of the engraving area.

[0035] The greater the temperature diffusivity, the greater the material's reaction when the laser beam is irradiated on the engraving area, resulting in a greater heat conduction effect. If the power is too high at this time, the engraving area will overheat and the material will melt. The smaller the temperature diffusivity, the smaller the material's resistance to the laser beam, resulting in the temperature of the engraving area being concentrated at the focal point of the laser beam, and the heat cannot be effectively transferred to other locations. If the power is too low at this time, the engraving area will have shallow marks and fail to meet the task requirements. Therefore, it is necessary to analyze the temperature distribution in the engraving area at each moment to obtain the temperature diffusivity of the engraving area.

[0036] Preferably, in one embodiment of the present invention, the method for obtaining temperature diffusivity includes:

[0037] Get the average temperature of the engraving area. The higher the average temperature, the more adaptable the current material is to the laser beam, the lower the reflectivity to the laser, and the more heat it can absorb.

[0038] The temperature gradient characteristics of each position in the engraving area are obtained. The temperature gradient characteristics characterize the temperature change law at the corresponding position. The larger the gradient, the more obvious the data change at the corresponding position. If the material has good thermal conductivity, the temperature of the entire engraving area will show obvious diffusivity, resulting in a smaller temperature gradient characteristic of the entire area; on the contrary, if the material has poor adaptability to the laser beam, high reflectivity and poor thermal conductivity, the temperature will be concentrated in the focal area of ​​the laser beam, resulting in a larger gradient in the engraving area. Therefore, the average value of the temperature gradient characteristics at all positions is negatively correlated to obtain the initial temperature diffusivity. That is, the larger the temperature gradient characteristics, the poorer the temperature diffusion effect and the smaller the initial temperature diffusivity. Further combined with the average temperature, the product of the initial temperature diffusivity and the average temperature is normalized to obtain the temperature diffusivity.

[0039] Furthermore, the method for obtaining the degree gradient feature in the embodiment of the present invention includes:

[0040] Because the temperature change during the laser engraving process is transmitted from the center to the surrounding area, for each position in the engraving area, the direction from the center point of the engraving area to the position is taken as the temperature diffusion direction, the next position of the position in the corresponding temperature diffusion direction is taken as the comparison position, and the temperature difference between the position and the corresponding comparison position is taken as the temperature gradient feature.

[0041] It should be noted that, in one embodiment of the present invention, the negative correlation mapping method of the average value of the temperature gradient feature is in the form of an inverse number, because the heat diffusivity of the material during the actual engraving process will not lead to completely uniform heat in the engraving area, so the inverse of the average value of the temperature gradient feature can be directly used as the result of the negative correlation mapping, and the denominator will not be 0. The normalization method used to obtain the temperature diffusivity in the embodiment of the present invention is to use a nonlinear activation function mapping method for normalization. In other embodiments, a hyperbolic tangent function or a range may also be used, which is not limited or elaborated here.

[0042] Step S3: Obtain a power adjustment factor according to the temperature diffusivity and the engraving depth at each engraving moment, and adjust the initial power at the corresponding engraving moment according to the power adjustment factor.

[0043] The greater the temperature diffusivity, the better the thermal conductivity of the material, and the less power required; at the same time, considering that the greater the engraving depth required in the engraving task, the stronger the laser beam power is required. Therefore, the power adjustment factor can be obtained according to the temperature diffusivity and engraving depth at each engraving moment.

[0044] Preferably, in one embodiment of the present invention, the average engraving depth of all positions in this engraving task is counted, the depth deviation of the engraving depth at each position is obtained according to the average engraving depth, and the power adjustment factor is obtained according to the depth deviation and temperature diffusivity. The depth deviation is a relative value, that is, the relative deviation of the engraving depth at each position is analyzed based on the average engraving depth, and the engraving depth of the current engraving position can be accurately characterized by the depth deviation.

[0045] Preferably, in one embodiment of the present invention, considering that the temperature diffusivity is negatively correlated with the power adjustment, while the engraving depth is positively correlated with the power adjustment, in order to enable the two to be integrated to obtain the power adjustment factor, the method for obtaining the depth deviation includes: obtaining the ratio of the average engraving depth to the engraving depth of each position, and taking the difference between the ratio and the positive integer 1 as the depth deviation. That is, the larger the depth deviation, the smaller the engraving depth of the current position is relative to the average engraving depth, and a smaller power is required for engraving; similarly, the larger the temperature diffusivity, the smaller the power is required for engraving. Based on this, further in an embodiment of the present invention, the depth deviation is multiplied by the temperature diffusivity, and the value range of the multiplication result is mapped to between -1 and 1 to obtain the power adjustment factor. The mapping method is to map through a hyperbolic tangent function. After mapping, the power adjustment factor has positive and negative signs. The larger the power adjustment factor, the more it is necessary to reduce the current initial power. Conversely, the smaller the power adjustment factor, the more it is necessary to increase the current initial power. Therefore, in an embodiment of the present invention, the method for adjusting the initial power is:

[0046] The difference between the positive integer 1 and the power adjustment factor is used as the adjustment coefficient. Multiply the adjustment coefficient by the initial power at the corresponding engraving moment to obtain the adjusted power. If the power adjustment factor is a negative value, it means that the power adjustment factor is small, and the material at the current position requires a larger power to be engraved. The initial power needs to be increased, and the obtained adjustment coefficient is a positive value greater than 1, and the increased power can be obtained by multiplication. If the power adjustment factor is a large positive value, it means that the power adjustment factor is large, and the thermal conductivity of the material at the current position is better, and only a small power is needed to complete the engraving, so the initial power needs to be reduced. At this time, the obtained adjustment coefficient is a positive value less than 1, and the reduced power is obtained by multiplication.

[0047] In summary, the embodiments of the present invention take into account that different materials have different feedbacks on the laser beam in laser engraving, and laser engraving mainly relies on the temperature of the laser beam. For materials with good thermal conductivity and compatible with laser engraving, engraving does not require excessive power. Therefore, the temperature information in the laser beam engraving area on the mobile phone case is analyzed to obtain temperature diffusivity, which can be used to characterize the degree of compatibility between the material and the laser beam at the current position of the mobile phone case. Further considering the required engraving depth, the power adjustment factor can be obtained. Adjusting the initial power according to the power adjustment factor can avoid the problem of overheating or insufficient engraving of the current material caused by the initial power.

[0048] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0049] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A laser engraving device for a mobile phone case, comprising a laser engraving device body, characterized in that: A temperature monitoring device is installed on the laser engraving device body; the temperature monitoring device is used to monitor the temperature of the engraving area of ​​the laser beam on the mobile phone shell during the laser engraving process; The laser engraving device also includes a power control system, which receives the temperature data transmitted by the temperature monitoring device, and counts the engraving depth of each position on the mobile phone case in this engraving task; at each engraving moment in the laser engraving process, analyzes the temperature distribution in the engraving area to obtain the temperature diffusivity of the engraving area; obtains a power adjustment factor according to the temperature diffusivity and engraving depth at each engraving moment; and adjusts the initial power at the corresponding engraving moment according to the power adjustment factor; The method for obtaining the temperature diffusivity comprises: Obtaining the average temperature of the engraving area; obtaining the temperature gradient characteristics of each position in the engraving area, performing negative correlation mapping on the average values ​​of the temperature gradient characteristics of all positions, and obtaining the initial temperature diffusivity; normalizing the product of the initial temperature diffusivity and the average temperature to obtain the temperature diffusivity; The method for acquiring the temperature gradient characteristics comprises: For each position in the engraving area, the direction from the center point of the engraving area to the position is used as the temperature diffusion direction, the next position of the position in the corresponding temperature diffusion direction is used as the comparison position, and the temperature value difference between the position and the corresponding comparison position is used as the temperature gradient feature.

2. The laser engraving device for mobile phone case according to claim 1, characterized in that: The method for obtaining the power adjustment factor includes: The average engraving depth of all positions in this engraving task is counted, the depth deviation of the engraving depth of each position is obtained according to the average engraving depth, and the power adjustment factor is obtained according to the depth deviation and the temperature diffusivity.

3. The laser engraving device for mobile phone case according to claim 2, characterized in that: The method for obtaining the depth deviation includes: The ratio of the average engraving depth to the engraving depth at each position is obtained, and the difference between the ratio and the positive integer 1 is used as the depth deviation.

4. The laser engraving device for a mobile phone case according to claim 3, characterized in that: The obtaining the power adjustment factor according to the depth deviation and the temperature diffusivity comprises: The depth deviation is multiplied by the temperature diffusivity, and the value range of the multiplication result is mapped to between -1 and 1 to obtain the power adjustment factor.

5. The laser engraving device for mobile phone case according to claim 4, characterized in that: The step of adjusting the initial power at the corresponding engraving moment according to the power adjustment factor includes: The difference between the positive integer 1 and the power adjustment factor is used as the adjustment coefficient, and the adjustment coefficient is multiplied by the initial power at the corresponding engraving moment to obtain the adjusted power.

6. The laser engraving device for a mobile phone case according to claim 1, characterized in that: Before this engraving task, set the initial power at the corresponding position according to the required engraving depth, engraving area and engraving speed at each position.

7. The laser engraving device for a mobile phone case according to claim 6, characterized in that: The initial power is obtained by multiplying the engraving depth required for each position, the engraving area, and the preset proportional coefficient of the engraving speed.

8. The laser engraving device for a mobile phone case according to claim 1, characterized in that: The temperature monitoring device is an infrared camera.

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