A single-laser multi-mirror printing device and method based on an acousto-optic modulator

Abstract

The application discloses a single-laser multi-mirror printing device and method based on an acousto-optic modulator, and belongs to the technical field of 3D printing. The device comprises an acousto-optic modulator and n mirror modules, wherein n is an integer greater than 1. The acousto-optic modulator is used for switching the collimated laser beams to the n mirror modules in sequence, and the time for one round of switching is t. The mirror module is used for reflecting the switched laser beams to a printing work surface and performing uniform-speed scanning. The time t for one round of switching of the acousto-optic modulator satisfies t < D / V, wherein D is the diameter of the laser beam, and V is the scanning speed of the mirror module with the slowest scanning speed. Time and beam division scanning is realized, so that the independent switching of the laser beam corresponding to each mirror module does not affect the normal printing of other mirror modules, and the cost of the laser in multi-laser printing can be effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology, specifically relating to a single-laser multi-mirror printing device and method based on an acousto-optic modulator. Background Technology

[0002] Traditional laser galvanometer systems use a single laser with a single galvanometer module to scan part patterns. Printing part patterns with a single laser beam is very inefficient. To improve efficiency, a common approach is to use multiple laser galvanometer modules for printing. Currently available products can print with up to 36 laser galvanometer modules simultaneously.

[0003] With the development of the manufacturing industry, the price of galvanometer modules has decreased significantly, while the price of pure single-mode high-beam-quality fiber lasers remains high, costing more than 10 times that of galvanometer modules. Therefore, the cost bottleneck for multi-laser galvanometer printing lies in the laser itself. In particular, the emerging 3D printing of high-reflectivity materials requires high-power pure single-mode green lasers, which are more than 100 times more expensive than galvanometer modules.

[0004] To reduce laser costs, one approach is to split the laser beam from a single laser into multiple beams, each then incident on a different galvanometer module. While commonly used laser beam-splitting prisms can achieve this, the simultaneous splitting of a single laser beam presents a problem. If one galvanometer has finished printing its pattern and its laser needs to be turned off, the lasers of the remaining galvanometers are also shut off, preventing the unfinished printing from continuing.

[0005] Therefore, there is a need for a device and method that can split a single laser beam into multiple beams, with each galvanometer's laser beam being switched independently without affecting the normal printing of other galvanometers. Summary of the Invention

[0006] The purpose of this invention is to provide a single-laser multi-mirror printing device and method based on an acousto-optic modulator, so as to solve the problem of mutual interference between mirrors when printing with simultaneously split laser beams.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] This invention relates to a single-laser multi-mirror printing device based on an acousto-optic modulator, comprising an acousto-optic modulator and n mirror modules, where n is an integer greater than 1; the acousto-optic modulator is used to sequentially switch a collimated laser beam to the n mirror modules, with a switching time of t; the mirror modules are used to reflect the switched laser beam onto the printing surface and perform uniform scanning.

[0009] The time t for the acousto-optic modulator to perform one round of switching satisfies:

[0010] t < D / V,

[0011] Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

[0012] Preferably, it further includes a beam splitting mechanism, and the number of acousto-optic modulators is also n; the beam splitting mechanism is used to split the collimated laser beam into n laser beams, and the acousto-optic modulators correspond one-to-one with the galvanometer modules. Each acousto-optic modulator is located on the optical path of each laser beam after beam splitting, and is used to control the on / off state of the laser beam entering the corresponding galvanometer module.

[0013] This invention also relates to a single-laser multi-mirror printing method based on an acousto-optic modulator, comprising the following steps:

[0014] S1. Turn on the laser beam and start all galvanometer modules. The galvanometer modules operate at their respective scanning speeds.

[0015] S2. The collimated laser beam is sequentially switched to n galvanometer modules using an acousto-optic modulator, and then the laser beam is reflected onto the printing surface by the corresponding galvanometer module for uniform scanning; the time for one round of switching is t, and the following conditions are met:

[0016] t < D / V,

[0017] Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

[0018] Preferably, the acousto-optic modulator is one unit. Before the laser beam and galvanometer module are turned on in step S1, the angle value that the acousto-optic modulator needs to deflect the laser beam is calculated based on the respective positions of the galvanometer module, and the corresponding ultrasonic frequency input to the acousto-optic modulator is derived based on each angle value.

[0019] The S2 sequentially inputs ultrasonic frequencies into the acousto-optic modulator, thereby sequentially switching the collimated laser beam to n galvanometer modules. The time interval between the input ultrasonic frequencies on adjacent sides is t0, where t0 = t / n.

[0020] Preferably, the number of acousto-optic modulators is also n, and a beam splitting mechanism is provided in front of the n acousto-optic modulators. The beam splitting mechanism is used to split the collimated laser beam into n laser beams. The acousto-optic modulators correspond one-to-one with the galvanometer module, and each acousto-optic modulator is located on the optical path of each laser beam after beam splitting.

[0021] Each acousto-optic modulator in S2 controls the on / off state of the laser beam injected into the corresponding galvanometer module, thereby sequentially switching the collimated laser beam to n galvanometer modules.

[0022] Preferably, in step S2, while the acousto-optic modulator switches the laser beam, it simultaneously adjusts the laser power P0 of the laser beam in real time: P0 = n·P.

[0023] Where P is the power required for the current scanning of the galvanometer module.

[0024] Preferably, in step S2, when the acousto-optic modulator switches the laser beam to a certain galvanometer module, if the galvanometer module has no scanning data, the laser beam is turned off.

[0025] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0026] The single-laser multi-mirror printing device and method based on an acousto-optic modulator of the present invention uses an acousto-optic modulator to sequentially switch the collimated laser beam to n galvanometer modules, and strictly controls the interval time of the acousto-optic modulator switching the laser beam. Then, the laser beam is reflected onto the printing surface by the corresponding galvanometer module for uniform scanning, thereby realizing time-division and beam-division scanning. This ensures that the independent switching of the laser beam corresponding to each galvanometer module does not affect the normal printing of other galvanometer modules, and can effectively reduce the cost of laser in multi-laser printing. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the single-laser multi-mirror printing device based on an acousto-optic modulator in Example 1;

[0028] Figure 2 is a schematic diagram of the printing method based on the printing device involved in Embodiment 1;

[0029] Figure 3 is a schematic diagram of the single-laser multi-mirror printing device based on an acousto-optic modulator in Example 2.

[0030] Figure reference numerals: 1-acoustic-optic modulator, 2-galvanometer module, 3-spectral splitting mechanism. Detailed Implementation

[0031] To further understand the content of this invention, the invention will be described in detail with reference to the embodiments. The following embodiments are used to illustrate the invention, but are not intended to limit the scope of the invention.

[0032] Example 1

[0033] See attached document Figure 1 As shown, the present invention relates to a single-laser multi-mirror printing device based on an acousto-optic modulator, comprising one acousto-optic modulator 1 and n mirror modules 2, where n is an integer greater than 1, and in this embodiment n=3.

[0034] The acousto-optic modulator 1 is used to sequentially switch the collimated laser beam to n galvanometer modules. The principle of beam splitting using the acousto-optic modulator 1 is as follows: The acousto-optic modulator 1 modulates a signal in an acousto-optic crystal, which acts as an electrical signal on the ultrasonic transducer, and then converts it into a mechanical ultrasonic field that changes in the form of an electrical signal. When the light wave passes through the medium, its beam direction is deflected due to the diffraction of the grating. The beam deflection angle is related to the ultrasonic frequency input to the acousto-optic modulator. By continuously changing the frequency of the ultrasonic wave, the beam deflection angle θ can be changed. Different deflection angles require different ultrasonic frequencies. The deflection speed of the beam by the acousto-optic modulator 1 is the transit time of the ultrasonic wave through the beam. Taking a 1mm thick beam and an ultrasonic speed of 5000m / s as an example, the acousto-optic modulator modulates the laser beam for 0.2us, meaning that the acousto-optic modulator can change the beam angle in 0.2us, which meets the beam switching time required by the printing principle of this scheme. The structure and working principle of the acousto-optic modulator 1 are conventional techniques in this field.

[0035] The time t for one round of switching of the acousto-optic modulator 1 is called one round of switching, which refers to the time it takes for the laser beam to pass through each galvanometer module 2 in sequence. The time t for one round of switching of the acousto-optic modulator satisfies the following:

[0036] t < D / V,

[0037] Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

[0038] The galvanometer module is used to reflect the switched laser beam onto the printing surface and perform uniform scanning.

[0039] The printing method based on the above-mentioned single-laser multi-mirror printing device using an acousto-optic modulator includes the following steps:

[0040] S1. Based on the respective positions of the galvanometer modules 2, calculate the angle value that each acousto-optic modulator 1 needs to deflect the laser beam, and derive the corresponding ultrasonic frequencies f1, f2 and f3 input to the acousto-optic modulator 1 based on each angle value; turn on the laser beam and start all galvanometer modules, and the galvanometer modules run according to their respective scanning speeds;

[0041] S2. The collimated laser beam is sequentially switched to n galvanometer modules 2 via the acousto-optic modulator 1. Specifically, ultrasonic frequencies are input to the acousto-optic modulator 1 in the order of f1, f2, and f3, causing the split laser beam to sequentially enter three different galvanometer modules 2. The corresponding galvanometer modules 2 then reflect the laser beam onto the printing surface for uniform scanning. Figure 2 As shown; the time for one round of switching is t, and it satisfies:

[0042] t < D / V,

[0043] Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

[0044] For example, in metal 3D sintering printing, the scanning speed of the galvanometer is 1000 mm / s and the spot diameter is 100 μm. Therefore, t < 0.1 ms, which means that the total time for each round of switching between multiple galvanometers cannot exceed 0.1 ms.

[0045] The time interval between adjacent input ultrasonic frequencies is t0, where t0 = t / n.

[0046] See attached document Figure 2 As shown, the single laser beam sequentially switches between the scanning lines of different galvanometer modules according to the numerical order in the diagram. When a galvanometer module currently has no printing pattern, the laser power is turned off when the laser beam switches to that module. The laser power is turned on again when the laser beam switches to the next galvanometer module. At this time, there is no printing pattern data for that galvanometer, which does not affect the normal printing of patterns by the other galvanometers.

[0047] When printing parts, the power and scanning speed requirements for printing patterns on different parts are also different. Therefore, the splitting power of the same laser beam must also be different when it is split to each galvanometer module 2. Thus, the incident laser power needs to be rapidly adjusted according to the laser power required for the printing process of each galvanometer module 2. Real-time adjustment of the laser beam power P0:

[0048] P0 = n·P,

[0049] Where P is the power required for the current scanning of the galvanometer module.

[0050] Repeat step S2 until all data from galvanometer module 2 has been printed, then turn off the laser.

[0051] Example 2

[0052] See attached document Figure 3 As shown, this embodiment, based on embodiment 1, further includes a beam splitting mechanism 3 and increases the number of acousto-optic modulators 1. The beam splitting mechanism 3 can be a beam splitting prism, and the number of acousto-optic modulators 1 is increased to n. The beam splitting mechanism 3 is used to split the collimated laser beam into n laser beams. The acousto-optic modulators 1 correspond one-to-one with the galvanometer module 2, and each acousto-optic modulator 1 is located on the optical path of each laser beam after splitting, used to control the on / off state of the laser beam entering the corresponding galvanometer module 2.

[0053] The printing method based on the above-mentioned single-laser multi-mirror printing device using an acousto-optic modulator includes the following steps:

[0054] S1. The laser beam is turned on and all galvanometer modules are started. The galvanometer modules run at their respective scanning speeds. At this time, the collimated laser beam is first split by the beam splitting mechanism 3 to form 3 laser beams, which are then injected into the 3 acousto-optic modulators 1 in sequence.

[0055] S2. The collimated laser beam is sequentially switched to n galvanometer modules 2 by the acousto-optic modulator 1. That is, each acousto-optic modulator 1 controls the on / off state of the laser beam entering the corresponding galvanometer module, allowing only one acousto-optic modulator 1 to pass through the laser beam at a time, sequentially switching the collimated laser beam to the n galvanometer modules, and then the corresponding galvanometer module 2 reflects the laser beam onto the printing surface for uniform scanning, such as... Figure 2 As shown; the time for one round of switching is t, and it satisfies:

[0056] t < D / V,

[0057] Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

[0058] The present invention has been described in detail above with reference to the embodiments, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A single-laser multi-mirror printing device based on an acousto-optic modulator, characterized in that: It includes an acousto-optic modulator and n galvanometer modules, where n is an integer greater than 1; the acousto-optic modulator is used to sequentially switch the collimated laser beam to the n galvanometer modules, and the time for one round of switching is t; The galvanometer module is used to reflect the switched laser beam onto the printing surface and perform uniform scanning; The time t for the acousto-optic modulator to perform one round of switching satisfies: t < D / V, Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

2. The single-laser multi-mirror printing device based on an acousto-optic modulator according to claim 1, characterized in that: It also includes a beam splitting mechanism, and the number of acousto-optic modulators is also n; the beam splitting mechanism is used to split the collimated laser beam into n laser beams, and the acousto-optic modulators correspond one-to-one with the galvanometer modules. Each acousto-optic modulator is located on the optical path of each laser beam after beam splitting, and is used to control the on / off state of the laser beam entering the corresponding galvanometer module.

3. A single-laser multi-mirror printing method based on an acousto-optic modulator, characterized in that, Includes the following steps: S1. Turn on the laser beam and start all galvanometer modules. The galvanometer modules operate at their respective scanning speeds. S2. The collimated laser beam is sequentially switched to n galvanometer modules using an acousto-optic modulator, and then the laser beam is reflected onto the printing surface by the corresponding galvanometer module for uniform scanning; the time for one round of switching is t, and the following conditions are met: t < D / V, Where D is the laser beam diameter and V is the scanning speed of the galvanometer module with the slowest scanning speed.

4. The single-laser multi-mirror printing method based on an acousto-optic modulator according to claim 3, characterized in that: The acousto-optic modulator is one unit. Before the laser beam and galvanometer module are turned on in step S1, the angle value that the acousto-optic modulator needs to deflect the laser beam is calculated based on the respective positions of the galvanometer module, and the corresponding ultrasonic frequency input to the acousto-optic modulator is derived based on each angle value. The S2 sequentially inputs ultrasonic frequencies into the acousto-optic modulator, thereby sequentially switching the collimated laser beam to n galvanometer modules. The time interval between the input ultrasonic frequencies on adjacent sides is t0, where t0 = t / n.

5. The single-laser multi-mirror printing method based on an acousto-optic modulator according to claim 3, characterized in that: The number of acousto-optic modulators is also n. A beam splitting mechanism is provided in front of the n acousto-optic modulators. The beam splitting mechanism is used to split the collimated laser beam into n laser beams. The acousto-optic modulators correspond one-to-one with the galvanometer module. Each acousto-optic modulator is located on the optical path of each laser beam after beam splitting. Each acousto-optic modulator in S2 controls the on / off state of the laser beam injected into the corresponding galvanometer module, thereby sequentially switching the collimated laser beam to n galvanometer modules.

6. The single-laser multi-mirror printing method based on an acousto-optic modulator according to claim 3, characterized in that: In step S2, while the acousto-optic modulator switches the laser beam, it simultaneously adjusts the laser power P0 of the laser beam in real time: P0 = n·P. Where P is the power required for the current scanning of the galvanometer module.

7. The single-laser multi-mirror printing method based on an acousto-optic modulator according to claim 3, characterized in that: In step S2, when the acousto-optic modulator switches the laser beam to a certain galvanometer module, if the galvanometer module has no scanning data, the laser beam is turned off.

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