A method for compensating the light intensity of a light source and a light curing machine

Abstract

The present invention discloses a method for compensating the light intensity of a light source and a light curing machine. The method for compensating the light intensity of the light source includes: selecting a light intensity compensation time point according to the light attenuation characteristic of the light source; recording the working duration of the light source, and when the working duration of the light source reaches the light intensity compensation time point, obtaining the light intensity compensation value corresponding to the light intensity compensation time point; and increasing the light intensity of the light source according to the light intensity compensation value so that the light intensity of the light source is maintained within a predetermined light intensity range. This method for compensating the light intensity of the light source utilizes the light attenuation characteristic of the light source to select the light intensity compensation time point. When the working duration of the light source reaches the light intensity compensation time point, the light intensity of the light source is compensated so that the light intensity of the light source is maintained within a predetermined light intensity range. Compared with the existing closed-loop control method that needs to use a light intensity sensor to detect the light intensity of the light source, the light intensity detection module is reduced, the control system is simplified, the computing power requirement for system feedback operation is reduced, and thus the overall system cost is reduced. This invention is used in the field of 3D printing technology.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and particularly to a method for compensating light intensity of a light source and a light curing machine. Background Art

[0002] At present, there are many types of 3D printer technologies on the market. According to different incremental processes, the main differences lie in the lamination method and the materials used. For example, extrusion-type fused deposition modeling (FDM), particle-type selective laser sintering (SLS), lamination-type laminated object manufacturing (LOM), and photopolymerization-type digital light processing technology (DLP), etc. The printing material corresponding to the DLP technology is liquid photosensitive resin, which is a special resin that polymerizes and crosslinks under the action of a photoinitiator under ultraviolet irradiation. That is to say, the photocuring technology is the core of the DLP printing technology.

[0003] Post-curing is an important link in the 3D printing process. After 3D printing is completed, the product taken out of the material tray cannot reach 100% curing degree. Therefore, post-treatment operations of post-curing in a UV box are required to increase the curing rate of the material and its mechanical properties. The products after post-curing have the advantages of hard surface, non-sticking, and scratch resistance.

[0004] In the post-curing process, whether using a traditional mercury lamp or a new technology UV LED (ultraviolet light-emitting diode) light curing machine, as the irradiation time increases, the intensity of the light emitted by the light source will more or less decrease, which is usually called "light attenuation" in the industry. Light attenuation will cause quality accidents in production.

[0005] After testing, it is found that the UV LEDs in the currently used UV post-curing machines on the market (refer to Figure 1 ) have a trend of light intensity attenuation after working for a certain period of time. Refer to Figure 2 , the specific performance of the currently used UV lamp beads on the market is that the light intensity attenuates by 90% after about 4000 hours of normal temperature aging and by 90% after about 1000 hours of high temperature aging. According to calculations, the light intensity of the LED light source attenuates by 90% after a fixed working duration in a fixed working environment. Therefore, after the above-mentioned certain usage time, the light intensity of the ultraviolet lamp beads in the light curing machine will attenuate. Since the weaker the light intensity, the longer the curing time required for 3D printed products, under the same curing setting time, it is very likely that the curing rate of the products will be insufficient, resulting in product quality problems.

[0006] Currently, in order to avoid insufficient curing rate of 3D printed products, the light curing machines on the market adopt the method of detecting light intensity (using a light intensity sensor) and a feedback system for light intensity reinforcement, that is, closed-loop control. However, the separate supplementation of light intensity requires the addition of a detection unit and complex arithmetic logic, increasing the equipment cost. In addition, this measurement and calibration are prone to abnormal calibration due to other light interference in the system or defects in the algorithm, thus affecting the use and even the stability of the system. Moreover, the use of a light intensity sensor requires users or maintenance personnel to measure and adjust it themselves, increasing the learning cost of users or the cost of maintenance personnel. Summary of the Invention

[0007] An object of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for compensating light intensity of a light source and a light curing machine, which reduce the light intensity detection module and thus reduce the cost.

[0008] According to an embodiment of the first aspect of the present invention, a method for compensating light intensity of a light source is provided, including:

[0009] Selecting a light intensity compensation time point according to the light decay characteristic of the light source;

[0010] Recording the working duration of the light source, and when the working duration of the light source reaches the light intensity compensation time point, obtaining the light intensity compensation value corresponding to the light intensity compensation time point;

[0011] According to the light intensity compensation value, increasing the light intensity of the light source so that the light intensity of the light source is maintained within a predetermined light intensity range.

[0012] The above method for compensating light intensity of a light source has at least the following beneficial effects: selecting a light intensity compensation time point according to the light decay characteristic of the light source, and when the working duration of the light source reaches the light intensity compensation time point, compensating the light intensity of the light source so that the light source is maintained within a predetermined light intensity range to ensure the quality of the cured product. Compared with the existing closed-loop control method that needs to use a light intensity sensor to detect the light intensity of the light source, the light intensity detection module is reduced, the control system is simplified, the computing power requirement for system feedback operation is reduced, and thus the overall system cost is reduced; and the light source compensation is not affected by other light interference in the system, improving the stability of the light source compensation control.

[0013] According to the method for compensating light intensity of a light source described in the embodiment of the first aspect of the present invention, there are multiple light intensity compensation time points, and different light intensity compensation time points correspond to different light intensity compensation values.

[0014] According to the method for compensating light intensity of a light source described in the embodiment of the first aspect of the present invention, it includes: obtaining the light decay characteristic of the light source, performing a light decay test on the light source, collecting the working duration and the corresponding actual light intensity of the light source, and obtaining the relationship curve between the light decay time and the light intensity of the light source.

[0015] The method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention includes: selecting at least one time node as the light intensity compensation time point, obtaining the actual light intensity value corresponding to the light intensity compensation time point according to the relationship curve, comparing the actual light intensity value with the predetermined light intensity range, and setting the light intensity compensation value.

[0016] In the step of increasing the light intensity of the light source according to the light intensity compensation value so that the light intensity of the light source is maintained within a predetermined range in the method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention, the light intensity is increased by increasing the current of the light source.

[0017] The method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention includes: selecting a light intensity compensation limit point according to the light decay characteristic of the light source, when the working duration of the light source reaches the light intensity compensation limit point, no longer increasing the light intensity of the light source, obtaining the light intensity compensation value corresponding to the light intensity compensation limit point, and extending the single working duration of the light source according to the light intensity compensation value corresponding to the light intensity compensation limit point.

[0018] In the method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention, when the light source is the light source of a post-curing device, specifically extending the single working duration of the light source means: extending the single curing working duration of the light source of the post-curing device.

[0019] In the method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention, when the light source is the light source of a 3D printer, specifically extending the single working duration of the light source means: extending the single exposure duration of the light source of the 3D printer.

[0020] In the method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention, a temperature monitoring module is set to monitor the temperature of the light source in real time, and when the monitored temperature exceeds the predetermined temperature, the heat dissipation of the light source is increased.

[0021] In the method for compensating the light intensity of a light source according to the embodiment of the first aspect of the present invention, a light intensity sensor is set to measure the actual light intensity of the light source in real time, and when the actual light intensity of the light source is not within the predetermined light intensity range, the light intensity of the light source is adjusted.

[0022] According to the embodiment of the second aspect of the present invention, a method for compensating the light intensity of a light source is provided, including:

[0023] Selecting a light intensity compensation time point according to the light decay characteristic of the light source;

[0024] Recording the working duration of the light source, and when the working duration of the light source reaches the light intensity compensation time point, obtaining the light intensity compensation value and the curing time compensation value corresponding to the light intensity compensation time point;

[0025] According to the light intensity compensation value, increase the light intensity of the light source, and the light intensity of the light source after light intensity compensation is lower than the predetermined light intensity range;

[0026] According to the curing time compensation value, extend the duration of each single operation of the light source, so that the energy output by the light source is the same as the energy output by a light source with a light intensity within the predetermined light intensity range during the original single operation duration.

[0027] The above-mentioned light source light intensity compensation method has at least the following beneficial effects: selecting the light intensity compensation time point by using the light decay characteristic of the light source. When the working duration of the light source reaches the light intensity compensation time point, performing light intensity compensation and curing time compensation on the light source, so that the energy output by the light source remains the same as the original, to ensure the quality of the cured product. Compared with the existing closed-loop control method that needs to use a light intensity sensor to detect the light intensity of the light source, the light intensity detection module is reduced, the control system is simplified, the computing power requirement for system feedback operation is reduced, thereby reducing the overall system cost; and the light source compensation is not affected by other light interferences in the system, improving the stability of the light source compensation control.

[0028] According to an embodiment of the third aspect of the present invention, a light curing machine is provided, including a placement position for positioning and placing a product and at least one light source arranged around the placement position, and further including a control system, and the control system performs light intensity compensation on the light source by the above-mentioned light source light intensity compensation method.

[0029] The above-mentioned light curing machine has at least the following beneficial effects: the control system performs light intensity compensation on the light source by the above-mentioned light source light intensity compensation method, reducing the light intensity detection module and the computing power requirement for system feedback operation, thereby reducing the overall cost of the equipment. Description of the Drawings

[0030] The present invention will be further described below with reference to the drawings:

[0031] Figure 1 is a schematic internal structure diagram of a UV post-curing machine;

[0032] Figure 2 is an aging curve graph of a UV lamp bead. Detailed Embodiments

[0033] This part will describe the specific embodiments of the present invention in detail. The preferred embodiments of the present invention are shown in the drawings. The role of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the protection scope of the present invention.

[0034] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0035] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is more than two. Understandings such as greater than, less than, exceeding, etc. do not include the present number, and understandings such as above, below, within, etc. include the present number. If there is a description of first and second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0037] The embodiment of the present invention provides a method for compensating the light intensity of a light source, including the following steps:

[0038] S100. Select a light intensity compensation time point according to the light decay characteristic of the light source;

[0039] S200. Record the working duration of the light source (here, the working duration refers to the total cumulative light emission duration of the light source, rather than the duration of a single light emission operation). When the working duration of the light source reaches the light intensity compensation time point, obtain the light intensity compensation value corresponding to the light intensity compensation time point;

[0040] S300. According to the light intensity compensation value, increase the light intensity of the light source so that the light intensity of the light source is maintained within a predetermined light intensity range.

[0041] The method for compensating the light intensity of the light source in this embodiment uses the light decay characteristic of the light source to select the light intensity compensation time point. When the working duration of the light source reaches the light intensity compensation time point, the light intensity of the light source is compensated to keep the light source within a predetermined light intensity range to ensure the quality of the cured product. Compared with the existing closed-loop control method that needs to use a light intensity sensor to detect the light intensity of the light source, it reduces the light intensity detection module, simplifies the control system, reduces the computing power requirement of the system feedback operation, thereby reducing the overall system cost; and the light source compensation is not affected by other light interferences in the system, improving the stability of the light source compensation control.

[0042] It can be understood that the predetermined light intensity range can be an interval value, and as long as the light intensity of the light source is within this range, the basic photocuring effect can be satisfied; in addition, as an extreme case, the predetermined light intensity range can also be a certain value with an interval size of 0.

[0043] It can be understood that the setting of the predetermined light intensity range is based on ensuring the photocuring effect.

[0044] The light source light intensity compensation method of this embodiment is mainly used in the field of photocuring 3D printing. The light source that requires light intensity compensation is mainly the light source of the post-curing device (refer to Figure 1 ), and of course, it can also be the working light source of a photocuring 3D printer. Both are UV LEDs (ultraviolet light-emitting diodes).

[0045] Among them, during the DLP 3D printing process, the UV LED irradiates certain areas of the resin material for curing. The liquid resin is composed of a large number of free monomers and photoinitiators. The UV LED irradiates this mixture with strong ultraviolet light, causing the photoinitiators in it to react, and the free monomers combine together to form a solid polymer, and the product is initially printed, which is the primary curing stage. The cured resin is a cross-linked macromolecular polymer, that is, each part of it is directly connected to another part. However, after printing is completed, there are still many parts that do not reach the expected cross-linking degree, which affects the tensile strength and other properties of the product. Using ultraviolet light for post-curing can complete the process of molecular bonding and ensure the highest cross-linking degree.

[0046] Of course, it can be understood that according to needs, this light source light intensity compensation method can be applied to the adjustment of light sources with certain requirements for light intensity stability, where the light source has a certain light decay characteristic.

[0047] In this embodiment, in steps S100 and S200, the light intensity compensation time points can be multiple, depending on the application conditions of different light sources. At different light intensity compensation time points, the light decay degree of the light source is different, so the corresponding light intensity compensation values are different.

[0048] In some embodiments, in step S300, specifically, the light intensity is increased by increasing the current of the light source. According to the light intensity compensation value, the current of the light source is increased to increase the light intensity of the light source and maintain it within the predetermined light intensity range. Specifically, the current of the light source can be adjusted to a certain percentage of the original by the PID control algorithm to compensate for the loss of light intensity. In order to achieve the best adjustment effect, the PID adjustment is performed continuously for multiple times.

[0049] In some embodiments, the light source light intensity compensation method further includes the following steps:

[0050] S10. Obtain the light attenuation characteristics of the light source, conduct a light attenuation test on the light source, collect the working duration of the light source and the corresponding actual light intensity, and obtain the relationship curve between the light attenuation time and the light intensity of the light source.

[0051] S11. Select at least one time node as the light intensity compensation time point, that is, the light intensity compensation time point can be one or more. Obtain the actual light intensity value corresponding to the light intensity compensation time point according to the relationship curve, compare the actual light intensity value with the predetermined light intensity range, and set the light intensity compensation value. Generally, an intermediate value within the predetermined light intensity range can be selected, and the difference between this intermediate value and the actual light intensity value corresponding to the light intensity compensation time point is the light intensity compensation value, that is, the light intensity that the light source needs to increase.

[0052] It can be understood that steps S10 and S11 are before step S100.

[0053] Specifically, taking the UV LED as an example for further illustration:

[0054] S101. Collect UV LED light intensity data, and conduct data analysis on the collected data to obtain the range of the default light value;

[0055] S102. Enter the light intensity calibration mode, input the currently measured light intensity value, automatically compare and adjust it with the default value, so as to complete the adjustment of the light intensity consistency of the curing machine before leaving the factory;

[0056] S103. Calculate the range of the light power that needs to be compensated according to the product life, use an appropriate light power output, and design the cured product with a certain range of light intensity compensation;

[0057] S104. Through the control chip, record the cumulative curing time of the curing box in batches. When the cumulative time reaches the designed value, adjust the UV LED output control so that the overall light intensity rises to a certain percentage, thereby compensating for the loss of light intensity. This step can simulate the light intensity compensation effect;

[0058] S105. Collect the light intensity life data of the UV LED, calculate the aging curve of the UV LED, and design the light intensity compensation through software algorithms according to the actual aging data.

[0059] In some embodiments, the light intensity compensation method for this light source further includes the following steps:

[0060] S400. According to the light attenuation characteristics of the light source, select the light intensity compensation limit point. When the working duration of the light source reaches the light intensity compensation limit point, no longer increase the light intensity of the light source. Obtain the light intensity compensation value corresponding to the light intensity compensation limit point, and extend the single working duration of the light source according to the light intensity compensation value corresponding to the light intensity compensation limit point.

[0061] Since most of the curing boxes on the market use UV LEDs as light sources (UV LEDs have the advantages of narrow spectrum, high light intensity, environmental protection, etc.), the volt-ampere characteristics of the internal PN junction limit the current of the UV LED from changing over a wide range. Moreover, the lifespan of the UV LED is closely related to the current flowing through it. If the light intensity attenuation is too large, it will lead to the inability to achieve the optimal adjustment effect only by adjusting the current. At this time, by extending the duration of the light source's single emission operation, the energy output by the light source can be increased, and in this way, the effect and product quality can be ensured as well.

[0062] Among them, in step S400, if the light source is the light source of the post-curing device, specifically extending the duration of the light source's single operation means: extending the duration of the single curing operation of the light source of the post-curing device.

[0063] In step S400, if the light source is the light source of the 3D printer, specifically extending the duration of the light source's single operation means: extending the duration of the single exposure of the light source of the 3D printer.

[0064] In some embodiments, this light source light intensity compensation method further includes the following steps:

[0065] S500. Set up a temperature monitoring module to monitor the temperature of the light source in real time. When the monitored temperature exceeds the predetermined temperature, increase the heat dissipation of the light source. The light intensity attenuation of the light source is related to the temperature. When the temperature of the light source is below the predetermined temperature, it can make the current light intensity attenuation of the light source more in line with the pre-measured light attenuation characteristics, that is, the relationship curve between the light attenuation time and the light intensity in step S10, so as to ensure the accuracy of the light intensity compensation.

[0066] S600. Set up a light intensity sensor to measure the actual light intensity of the light source in real time. When the actual light intensity of the light source is not within the predetermined light intensity range, adjust the light intensity of the light source. By setting up a light intensity sensor, closed-loop control is realized, and the light intensity is further adjusted according to the feedback of the sensor.

[0067] The embodiment of the present invention also provides another light source light intensity compensation method, including the following steps:

[0068] a. Select the light intensity compensation time point according to the light attenuation characteristics of the light source;

[0069] b. Record the working duration of the light source. When the working duration of the light source reaches the light intensity compensation time point, obtain the light intensity compensation value and the curing time compensation value corresponding to the light intensity compensation time point;

[0070] c. According to the light intensity compensation value, increase the light intensity of the light source, and the light intensity of the light source after light intensity compensation is lower than the predetermined light intensity range;

[0071] d. According to the curing time compensation value, extend the duration of each single operation of the light source, so that the energy output by the light source is the same as the energy output by the light source with the light intensity within the predetermined light intensity range within the original duration of each single operation.

[0072] The second method for compensating the light intensity of the light source is similar to the first method for compensating the light intensity of the light source described above. The main difference between the two is that after compensating the light intensity according to the light intensity compensation value in the second compensation method, the light intensity of the light source can be lower than the predetermined light intensity range, but at the same time, it is necessary to extend the duration of each single operation of the light source. In this way, it can also ensure that the energy output by the light source meets the light curing effect and can achieve the same effect of reducing the system cost.

[0073] It can be understood that for other steps of the second method for compensating the light intensity of the light source, reference can be made to steps S10, S11, S400, S500, and S600 of the first method.

[0074] Refer to Figure 1 , an embodiment of the present invention further provides a light curing machine for the post-curing stage of a product, including a placement position for positioning and placing the product and at least one light source arranged around the placement position, and further including a control system. The control system compensates the light intensity of the light source by the first or second method for compensating the light intensity of the light source described above. Specifically, the light source uses a UVLED (ultraviolet light-emitting diode), and the number of UV LEDs can be set according to needs.

[0075] The control system of the light curing machine in this embodiment compensates the light intensity of the light source by the above-mentioned method for compensating the light intensity of the light source, reduces the light intensity detection module, and reduces the computing power requirement for system feedback operation, thereby reducing the overall cost of the equipment.

[0076] The above has described the embodiments of the present invention in detail with reference to the drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art in the technical field, various changes can be made without departing from the gist of the present invention.

Claims

1. A method for compensating the light intensity of a light source, characterized in that, Comprising: Select an optical intensity compensation time point according to the light decay characteristic of the light source; Record the working duration of the light source. When the working duration of the light source reaches the optical intensity compensation time point, obtain the optical intensity compensation value and the curing time compensation value corresponding to the optical intensity compensation time point; According to the optical intensity compensation value, increase the optical intensity of the light source, and the optical intensity of the light source after optical intensity compensation is lower than the predetermined optical intensity range; According to the curing time compensation value, extend the duration of a single operation of the light source, so that the energy output by the light source is the same as the energy output by a light source with an optical intensity within the predetermined optical intensity range within the original single operation duration.

2. The method for compensating the light intensity of a light source according to claim 1, wherein: There are multiple optical intensity compensation time points, and different optical intensity compensation time points correspond to different optical intensity compensation values.

3. The method for compensating the light intensity of a light source according to claim 1, characterized in that Comprising: Obtain the light decay characteristic of the light source, conduct a light decay test on the light source, collect the working duration of the light source and the corresponding actual optical intensity, and obtain the relationship curve between the light decay time and the optical intensity of the light source.

4. The method for compensating the light intensity of a light source according to claim 3, wherein Comprising: Select at least one time node as the optical intensity compensation time point, obtain the actual optical intensity value corresponding to the optical intensity compensation time point according to the relationship curve, compare the actual optical intensity value with the predetermined optical intensity range, and set the optical intensity compensation value.

5. The method for compensating the light intensity of a light source according to claim 1, wherein: In the step of increasing the optical intensity of the light source according to the optical intensity compensation value so that the optical intensity of the light source is maintained within the predetermined range, increase the current of the light source to increase the optical intensity.

6. The light intensity compensation method of a light source according to any one of claims 1 to 5, characterized in that, Comprising: According to the light decay characteristic of the light source, select an optical intensity compensation limit point. When the working duration of the light source reaches the optical intensity compensation limit point, no longer increase the optical intensity of the light source, obtain the optical intensity compensation value corresponding to the optical intensity compensation limit point, and extend the duration of a single operation of the light source according to the optical intensity compensation value corresponding to the optical intensity compensation limit point.

7. The method for compensating the light intensity of a light source according to claim 1, characterized in that: Set a temperature monitoring module to monitor the temperature of the light source in real time. When the monitored temperature exceeds the predetermined temperature, increase the heat dissipation of the light source.

8. The method for compensating the light intensity of a light source according to claim 1, wherein: Set an optical intensity sensor to measure the actual optical intensity of the light source in real time. When the actual optical intensity of the light source is not within the predetermined optical intensity range, adjust the optical intensity of the light source.

9. A light curing machine, characterized in that: Comprising a placement position for positioning and placing a product and at least one light source arranged around the placement position, and further comprising a control system, and the control system performs optical intensity compensation on the light source by the light source optical intensity compensation method according to any one of claims 1 to 8.

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