Light spot adjusting device

Abstract

The utility model belongs to the field of additive manufacturing, and relates to a light spot adjusting device which comprises a motor, a crank connecting rod assembly and a lens set. The motor drives the lens group to freely move along the axial direction of the lens group through the crank connecting rod assembly. The utility model provides the light spot adjusting device which is convenient to adjust and can effectively save the space in the optical axis direction.

Description

Technical Field

[0001] The utility model belongs to the field of additive manufacturing and relates to a light spot adjustment device, in particular to a light spot size dynamic adjustment device. Background Art

[0002] At present, additive manufacturing technology is used. In order to compensate for the optical-mechanical error, the focus offset (i.e., focusing) needs to be adjusted according to the actual situation, thereby changing the spot size at the working plane to achieve the purpose of controlling the spot energy density. The current mainstream focusing method is collimation focusing, that is, changing the spot size at the focal plane by controlling the movement of the lens group. The manual method of moving the lens group is difficult to achieve fine control of the stroke and is heavily dependent on the operator's experience. If the motor-screw-translation stage is used to move the lens group, it will occupy space in the direction of the optical axis, making it difficult to achieve miniaturization of the module, which increases the difficulty of optical-mechanical integration. Utility Model Content

[0003] In order to solve the above technical problems existing in the background technology, the utility model provides a light spot adjustment device which is easy to adjust and can effectively save space in the direction of the optical axis.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A light spot adjustment device is characterized in that: the light spot adjustment device comprises a motor, a crank-connecting rod assembly and a lens group; the motor drives the lens group to move freely along the axial direction of the lens group through the crank-connecting rod assembly.

[0006] The crank-connecting rod assembly comprises a driving rod and a connecting rod; the motor is connected to the driving rod and drives the driving rod to rotate around the axis of the motor's rotating shaft; the driving rod is connected to the mirror group through the connecting rod and drives the mirror group to move freely along the axial direction of the mirror group.

[0007] The driving rod is a rod, a cam or an eccentric wheel.

[0008] The above-mentioned light spot adjustment device also includes a guide shaft that penetrates the lens group along the thickness direction of the lens group, and the axial direction of the guide shaft is parallel to the moving direction of the lens group.

[0009] There are two guide shafts, and the two guide shafts run through the lens group in parallel from the edge of the lens group.

[0010] The light spot adjustment device also includes a displacement sensor which is placed on the lens group and moves synchronously with the lens group.

[0011] The above-mentioned light spot adjustment device also includes a proximity switch, and the proximity switch is arranged on the movement track of the lens group.

[0012] The proximity switch is arranged at the end of the moving track of the mirror group.

[0013] The above motor is a reduction motor or a transmission mechanism with self-locking.

[0014] The motor is a reduction motor with a brake or a worm gear transmission mechanism, and the lens group is a collimating lens group or a focusing lens group.

[0015] The advantages of the utility model are:

[0016] The utility model provides a light spot adjustment device, including a motor, a crank connecting rod assembly and a lens group; the motor drives the lens group to move freely along the axial direction of the lens group through the crank connecting rod assembly. The utility model drives the crank connecting rod assembly to rotate through the rotation of the motor, thereby driving the lens group to move freely along the axial direction of the lens group (collimating lens group or focusing lens group), and can finely adjust the stroke of the lens group, while facilitating focusing, and avoiding excessive reliance on the operator's experience; in addition, when the light spot adjustment device provided by the utility model is in use, the motor and the crank connecting rod assembly can be completely placed in the empty space on the optical axis side, which can greatly save the space in the direction of the optical axis and improve the integrability of the utility model. The light spot adjustment device provided by the utility model can be applied to dynamic focusing or dynamic adjustment of light spot size of SLM equipment or DED equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the light spot adjustment device provided by the utility model;

[0018] Figure 2 It is a schematic diagram of the top view of the light spot adjustment device provided by the utility model;

[0019] Figure 3 yes Figure 2 AA direction schematic diagram;

[0020] Figure 4 This is a simplified flow chart of the light spot adjustment device provided by the utility model when performing focusing;

[0021] in:

[0022] 1-motor; 2-prime driving rod; 3-connecting rod; 4-mirror group; 5-displacement sensor; 6-guide shaft; 7-proximity switch; 8-frame. DETAILED DESCRIPTION

[0023] See also Figure 1 , Figure 2 as well as Figure 3The utility model provides a light spot adjustment device, including a motor 1, a crank-connecting rod assembly and a lens group 4; the motor 1 drives the lens group 4 to move freely along the optical axis through the crank-connecting rod assembly. The utility model realizes the adjustment of the light spot size by the lens group 4 by converting the circular rotation motion of the output shaft of the motor 1 into the linear motion of the lens group 4. At the same time, the utility model adopts an electric method, which can finely adjust the stroke of the lens group 4, facilitate focusing, and effectively avoid over-reliance on the operator's experience. In addition, in the traditional solution of using a linear module to drive the lens group, the motor output shaft is parallel to the optical axis direction, resulting in the motor occupying the space in the optical axis direction, while in this solution, the motor output shaft is perpendicular to the optical axis direction, so that the motor does not occupy the space in the optical axis direction, and the size of the entire module in the optical axis direction can be shortened, thereby improving the optical-mechanical compatibility and the integrability of the utility model.

[0024] The crank-connecting rod assembly used in the present invention can be a structure similar to a concentric crank slider, which is characterized by a mechanism without a quick return characteristic, and the average speed of the outward movement (from the initial reference to the limit position) and the return movement (from the limit position to the initial reference) of the lens group 4 is the same, and the impact on the motor, the crank-connecting rod assembly and the hinge of the lens group is small. Exemplarily, the crank-connecting rod assembly includes a prime mover 2 and a connecting rod 3; the motor 1 is connected to the prime mover 2 and drives the prime mover 2 to rotate around the axis of the rotation axis of the motor 1; the prime mover 2 is connected to the lens group 4 through the connecting rod 3 and drives the lens group 4 to move freely along the axis of the lens group 4. Of course, the prime mover 2 can be a rod, or a cam or an eccentric wheel or other existing or conventional structures. Exemplarily, a frame 8 can also be set outside the crank-connecting rod assembly and the optical components to prevent powder contamination, and the motor 1 is usually set outside the frame 8.

[0025] The length of the driving rod 2 and the connecting rod 3 can be determined by the limit position. Figure 3 The position shown is the initial reference (determined according to the reference provided by the proximity switch 7), which can realize the movement of the mirror group 4 to the left by δ1mm and to the right by δ2mm. The length of the driving rod 2 is R, and the length of the connecting rod 3 is L. It can be seen that:

[0026] 2×R=δ1+δ2(1)

[0027] L=(R 2 +(δ1+δ2) 2 -2×(δ1+δ2)×R) 1 / 2 (2)

[0028] The light spot adjustment device also includes a guide shaft 6 that penetrates the lens group 4 along the thickness direction of the lens group 4, and the axial direction of the guide shaft 6 is parallel to the moving direction of the lens group 4. Exemplarily, there can be two guide shafts 6, and the two guide shafts 6 penetrate the lens group 4 in parallel from the edge of the lens group 4. Exemplarily, the output shaft of the motor 1 is rigidly connected to the prime mover 2, the prime mover 2 and the connecting rod 3 are connected in an articulated manner, and the connecting rod 3 and the lens group 4 are connected in an articulated manner. The guide shaft 6 is parallel to the optical axis and passes through the lens group 4, limiting the degree of freedom of the lens group 4, and realizing the movement of the lens group 4 in the direction of the optical axis. When the motor 1 rotates, the prime mover 2 provides the connecting rod 3 with a force in the direction of the connecting rod 3 and a torque in the direction perpendicular to the connecting rod 3. Further, under the restriction of the guide shaft 6, the force transmitted to the lens group 4 by the connecting rod 3 is decomposed into a force in the direction of the guide shaft 6, so that the lens group 4 moves axially on the guide shaft 6 along the guide shaft 6.

[0029] The light spot adjustment device also includes a displacement sensor 5 placed on the lens group 4 and moving synchronously with the lens group 4. The displacement sensor 5 is used to measure the position of the lens group 4 during movement, and according to the functional relationship between the linear motion distance of the lens group 4 and the light spot size on the working plane (established by the method of actual measurement and calibration, conventional technical means, no longer repeated here), the precise light spot size is determined to achieve closed-loop control of the system, thereby eliminating the need for travel limit, reducing the number of control units of the mechanism, and improving the reliability of the mechanism.

[0030] The light spot adjustment device further includes a proximity switch 7, which is arranged on the motion track of the lens group 4. Exemplarily, the proximity switch 7 is arranged at the end of the motion track of the lens group 4. The function of the proximity switch 7 is to serve as the initial reference of the collimating lens group 4, and only one set of proximity switches 7 is required. Each time the motor 1 is powered on and starts working, the lens group 4 is first moved to the initial reference, and then the collimation and focusing are started.

[0031] The motor 1 is a reduction motor or a transmission mechanism with self-locking. For example, the motor 1 can be a reduction motor with a brake or a worm gear transmission mechanism. Regardless of which transmission mechanism with self-locking is used, self-locking when power is off can be achieved to better control the spatial positioning of the lens group 4; the lens group 4 can be a collimating lens group or a focusing lens group, as long as the lens group can adjust the spot size by moving it in the direction of the optical path.

[0032] For example, the supporting parts in the utility model, such as the mirror seat, the driving rod 2 or the connecting rod 3, can be processed with lighter aluminum materials to reduce the overall weight and improve the convenience of integration; and the parts subjected to alternating loads can be processed with materials with higher hardness and better strength, such as bearing steel, to improve structural reliability.

[0033] Based on the light spot adjustment device provided by the utility model, when it is used specifically, its specific method is: see Figure 4First, the motor is powered on and the mirror group 4 is returned to the initial reference; secondly, the laser is enabled to emit light and the spot size is monitored; it is determined whether the spot needs to be resized (i.e., focused). If focusing is required, the mirror group is moved by the motor to adjust the position of the mirror group in the frame 8 along the optical path direction, so that the spot size on the working plane can be adjusted. At the same time, it is monitored whether the spot size meets the requirements. If so, additive printing is started. If not, the position of the mirror group is continued to be moved by the motor to focus the spot until the production requirements are met.

Claims

1. A light spot adjustment device, characterized in that: The light spot adjustment device comprises a motor (1), a crank-connecting rod assembly and a lens group (4); the motor (1) drives the lens group (4) to move freely along the axial direction of the lens group (4) via the crank-connecting rod assembly.

2. The light spot adjustment device according to claim 1, characterized in that: The crank-connecting rod assembly comprises a driving rod (2) and a connecting rod (3); the motor (1) is connected to the driving rod (2) and drives the driving rod (2) to rotate around the axis of the rotating shaft of the motor (1); the driving rod (2) is connected to the lens group (4) through the connecting rod (3) and drives the lens group (4) to move freely along the axis of the lens group (4).

3. The light spot adjustment device according to claim 2, characterized in that: The driving rod (2) is a rod, a cam or an eccentric wheel.

4. The light spot adjustment device according to claim 3, characterized in that: The light spot adjustment device further comprises a guide shaft (6) which penetrates the lens group (4) along the thickness direction of the lens group (4), and the axial direction of the guide shaft (6) is parallel to the moving direction of the lens group (4).

5. The light spot adjustment device according to claim 4, characterized in that: There are two guide shafts (6), and the two guide shafts (6) run in parallel from the edge of the lens group (4) through the lens group (4).

6. The light spot adjustment device according to claim 1, 2, 3, 4 or 5, characterized in that: The light spot adjustment device also includes a displacement sensor (5) which is placed on the lens group (4) and moves synchronously with the lens group (4).

7. The light spot adjustment device according to claim 6, characterized in that: The light spot adjustment device also includes a proximity switch (7), and the proximity switch (7) is arranged on the movement track of the lens group (4).

8. The light spot adjustment device according to claim 7, characterized in that: The proximity switch (7) is arranged at the end of the movement track of the lens group (4).

9. The light spot adjustment device according to claim 8, characterized in that: The motor (1) is a reduction motor or a transmission mechanism with a self-locking function.

10. The light spot adjustment device according to claim 9, characterized in that: The motor (1) is a reduction motor with a brake or a worm gear transmission mechanism, and the lens group (4) is a collimating lens group or a focusing lens group.

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