CN108803243A - A kind of digital projection 3D molding machines - Google Patents

Abstract

The invention relates to a digital projection 3D forming device, comprising: a projection device, a rotating device and a light output assembly; wherein, the rotation device can drive the light output assembly to rotate; the light output assembly includes a lens barrel and an optical flat plate, the light output surface of the lens barrel is The flat plate is fixedly arranged on the inclined surface of the lens barrel; the light emitted by the projection device exits from the optical plate after passing through the lens barrel or the rotating device and the lens barrel. The digital projection 3D forming device proposed by the present invention is based on the refraction principle of light in the optical flat plate, and utilizes the offset of the image by the inclined optical flat plate, coupled with the structural design of the high-speed rotating LED projection light machine, to generate an image that is space-dependent on the exposure time. Integral smoothing effect for surface homogenization for rapid 3D prototyping.

Description

A digital projection 3D molding device

technical field

The invention belongs to the technical field of 3D printing, and in particular relates to a digital projection 3D forming device.

Background technique

Digital Light Processing (DLP) technology is a new light curing technology developed in recent years. It is mainly used to make small-sized parts through surface exposure and projection. Compared with other photo-curing rapid prototyping methods, the method of directly projecting images by surface exposure has the advantages of short production time, low system cost, and simple process, and has become an important development direction in the field of 3D printing.

The existing DLP technology generally adopts the method of directly projecting images. This method has simple, convenient and direct technical characteristics, but the forming accuracy is limited by the spatial resolution of the DMD (digital micromirror) or liquid crystal array, and it is inevitable that the The surface of the workpiece produces jagged stripes and steps caused by the intrinsic distribution of the DMD or liquid crystal array.

In order to improve the molding accuracy and molding surface quality of 3D workpieces, someone proposed a multiple-exposure molding method using X-Y direction shifting. The technical solution is as follows: LED projection light machine will form a constant A mask pattern formed by a large number of pixels, the mask pattern is discretely arranged in space, and the resolution of the external and internal sub-pixel ranges is improved through multiple illumination and path planning. However, the above method can only refine the printing accuracy, refine the stripes and steps, and does not completely achieve the homogenization of the surface of the workpiece. For some rapid prototyping applications that require high surface quality, it is necessary to carry out the surface after the molding is completed. Polishing and grinding processes are not only time-consuming and labor-intensive, but also easily lose the forming accuracy of the workpiece itself.

Contents of the invention

In order to solve the above technical problems, the present invention proposes a digital projection 3D modeling device.

A digital projection 3D molding device, comprising: a projection device, a rotating device and a light output assembly;

Wherein, the rotating device can drive the light emitting component to rotate;

The light output component includes a lens barrel and an optical plate, the light output surface of the lens barrel is an inclined plane, and the optical plate is fixedly arranged on the inclined surface of the lens barrel;

The light emitted by the projection device exits the optical plate after passing through the lens barrel or the rotating device and the lens barrel.

Further, the inclination angle of the optical flat plate relative to the plane perpendicular to the axis of the lens barrel is equal to the incident angle when the light emitted by the projection device enters the optical flat plate.

Further, the inclination angle of the optical flat panel is set according to the pixel size projected by the projection device.

Further, the projection device is an LED projection light machine, and the light emitted by the projection device is ultraviolet light.

Furthermore, the digital projection 3D forming device further includes transparent quartz glass, and the transparent quartz glass window is arranged on the side of the optical plate away from the projection device.

Further, the digital projection 3D molding device also includes a transparent silica gel disc and a working surface, the transparent silica gel disc is set on the side of the transparent quartz glass window away from the projection device, and the working surface is placed on the transparent silica gel disc; the ultraviolet light output by the LED projection light machine is sequentially Through the optical flat plate, transparent quartz glass window and transparent silica gel disc, the light is irradiated on the working surface; through the rotation of the rotating device, the rotation of the lens barrel and the optical flat plate is driven and controlled, so as to realize the rotating exposure of each pixel in the projection space, and then realize the image space Integral over the angle, producing a smoothing effect.

Further, the offset of the ultraviolet light emitted by the LED projection light machine in the optical flat panel Wherein, n is the refractive index of the optical flat plate, i ₁ is the incident angle of ultraviolet light incident on the optical flat plate, unit is rad, the size of this incident angle is equal to the described inclination angle of the optical flat plate, h is the thickness of the optical flat plate.

Further, the luminous intensity per unit projected area is equal to the luminous intensity of the microfacet around a certain point on the light emitting surface in a given direction divided by the projected area of the microfacet perpendicular to the given direction, namely: Among them, α is the angle of the offset center of the main ray, ω is the angular velocity of the optical plate rotation, I is the projected luminous intensity of the LED projection light machine, L is the luminous intensity on the projected area, and s _n is the projection perpendicular to the given direction area; that is, the total luminance on a pixel is Where α=0, 2π, the unit of brightness is candela/m2.

Further, the rotating device is an electronically controlled rotating table, which drives and controls the rotation of the lens barrel and the optical plate through the rotation of the electrically controlled rotating table.

Further, the projection device is arranged below, above, left or right of the rotating device, and correspondingly, the light emitted by the projection device is projected from bottom to top, top to bottom, left to right or right to left respectively.

Beneficial effects of the present invention: the digital projection 3D forming device proposed by the present invention is based on the principle of refraction of light in an optical plate, using the offset of the image by the inclined optical plate, coupled with the structural design of the high-speed rotating LED projection light machine, to produce Smoothing effect of exposure time integration in image space for surface homogenization for rapid 3D prototyping.

In the digital projection 3D forming device proposed by the present invention, the LED projection optical machine is fixed, and the electric control rotary table drives the optical plate to rotate at high speed, thereby realizing the offset of ultraviolet light, and the brightness of the pixel in a given direction is integrated in the angle , according to the relationship between the angle and the angular velocity of the rotation of the optical plate and the exposure time, the blurring of the pixels is realized by changing the exposure time, which is reflected in the homogenization of the step pattern and the zigzag pattern in the 3D printing molding, and the molding accuracy is improved.

Description of drawings

Fig. 1 is a schematic structural view of a digital projection 3D forming device proposed by the present invention;

Fig. 2 is a schematic diagram of the refraction effect shown by the optical plate in the digital projection 3D forming device proposed by the present invention;

Fig. 3a is a schematic diagram of pixel brightness in the digital projection 3D forming device proposed by the present invention;

Fig. 3b is a schematic diagram of pixel luminance integration in the digital projection 3D forming device proposed by the present invention;

Fig. 4a is an effect diagram of pixels before integration in the digital projection 3D forming device proposed by the present invention;

Fig. 4b is a homogenization effect diagram of integrated pixels in the digital projection 3D modeling device proposed by the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings. However, those skilled in the art know that the present invention is not limited to the drawings and the following embodiments.

The digital projection 3D forming device proposed by the present invention is shown in FIG. 1 , including: LED projection light machine 1 , electric control rotary table 2 , lens barrel 3 and optical plate 4 .

For the convenience of description, the following takes the projection of light from the LED projection light machine 1 from bottom to top as an example to illustrate the position and structural relationship of the various components included in the digital projection 3D molding device. However, those skilled in the art know that the LED projection light machine 1 Light can also be projected from top to bottom, or from left to right or from right to left. The projected light path can be horizontal or at a certain angle with the horizontal direction, and the projected light path can also be vertical or vertical. It is at a certain angle, and the specific setting method can be determined according to the application environment or application occasion during use.

Those skilled in the art will know that other projection devices can be used for the LED projection light machine, and other rotating devices can be used for the electronically controlled rotating table.

The LED projection light machine 1 is fixed below the electric control rotary table 2 and does not contact with the electric control rotary table 2 .

The lens barrel 3 is embedded and fixed in the electric control rotary table 2, and the electric control rotary table 2 can drive the lens barrel 3 to rotate in a direction perpendicular to the optical path; the light incident part of the lens barrel 3 is aligned with the light exit part of the LED projector 1 , the light emitted by the light output part of the LED projection light machine 1 can directly enter the lens barrel 3, and can also enter the lens barrel 3 through the electric control rotary table 2; Enter the interior of the lens barrel 3; the light exit part of the lens barrel 3 is a slope, and the slope angle of the slope relative to the horizontal plane is equal to the incident angle i ₁ when the ultraviolet light is incident on the optical flat plate 4, as shown in FIG. 2 . The incident angle i ₁ of the ultraviolet light incident on the optical flat panel 4 can be set and adjusted according to the pixel size of the LED projector 1 . The internal size of the lens barrel 3 can allow all the ultraviolet light emitted by the LED projector 1 to pass through. Preferably, the lens barrel is cylindrical.

The optical plate 4 is fixedly placed on the inclined surface of the lens barrel 3 , so it can rotate together with the lens barrel 3 , and the inclination angle of the optical plate 4 relative to the horizontal plane is also an included angle i ₁ . The rotation of the lens barrel 3 and the optical flat plate 4 is driven and controlled by the rotation of the electronically controlled rotary table 2 .

The digital projection 3D molding device also includes a transparent quartz glass 5, and the transparent quartz glass window 5 is arranged above the optical flat plate 4, and plays a dustproof role for the optical flat plate 4 and the LED projection light machine 1.

The digital projection 3D forming device also includes a transparent silica gel disc 6 and a working surface 7, the transparent silica gel disc 6 is arranged above the transparent quartz glass window 5, and the working surface 7 is placed on the transparent silica gel disc 6.

The ultraviolet light output by the LED projection light machine 1 passes through the lens barrel 3 (or the electric control rotating table 2 and the lens barrel 3), the optical plate 4, the transparent quartz glass window 5, and the transparent silica gel disc 6 successively, and irradiates on the working surface 7; The rotation of the electronically controlled rotary table 2 drives and controls the rotation of the lens barrel 3 and the optical plate 4, so as to realize the rotating exposure of each pixel in the projection space, and then realize the integration of the angle in the image space, and produce a smoothing effect.

When the ultraviolet light emitted by the LED projection light machine 1 irradiates the optical flat panel 4, since the optical flat panel 4 has a refractive index n, the light will have a refraction effect in the optical flat panel 4, and the optical flat panel 4 will deflect the light to a certain degree in different directions. The inclination angle of the optical flat panel 4 is set according to the size of the pixel projected by the LED projection light machine 1, and the incident angle of the optical flat panel is the same as the inclination angle of the optical flat panel, thereby realizing the rotary exposure of a single pixel.

The digital projection 3D forming device proposed by the present invention is based on the refraction principle of light in the optical flat plate, and utilizes the offset of the image by the inclined optical flat plate, coupled with the structural design of the high-speed rotating LED projection light machine, to generate an image that is space-dependent on the exposure time. Integral smoothing effect for surface homogenization for rapid 3D prototyping.

As shown in Figure 2, the ultraviolet light emitted by the LED projection light machine 1 will be offset due to the refraction effect in the optical flat panel 4, and the offset amount Among them, n is the refractive index of the optical flat plate, i ₁ is the incident angle (unit is rad) of the light incident on the optical flat plate, the size of the incident angle is equal to the inclination angle of the optical flat plate, h is the thickness of the optical flat plate, suppose the LED projection light The pixel size of the machine is d×d, where d=2Δx, that is, the offset of the light is half of the pixel size.

Brightness is used to indicate the luminous characteristics of different positions and directions of the luminous surface. It shows the luminous intensity per unit projected area in this direction, which is equal to the luminous intensity of the microfacets around a certain point on the luminous surface divided by the luminous intensity in a given direction. The projected area of the microfacet perpendicular to the given direction, namely: Among them, α is the angle at which the principal ray deviates from the center, ω is the angular velocity of the rotation of the optical plate 4, I is the projection luminous intensity of the LED projection light machine, L is the luminous intensity on the projected area, and s _n is the angle perpendicular to the given direction Projected area; that is, the total luminance on a pixel is Where α=0, 2π, and the unit of luminance is candela/m2, as shown in Figure 3a.

As shown in Figure 3b, the integrated luminance is reflected in the blurring of pixels macroscopically, and the printing effect can be improved by changing the exposure time, and it is reflected in the homogenization of step lines and jagged stripes after 3D printing Processing, as shown in Figure 4a before the homogenization process, and as shown in Figure 4b after the homogenization process, a cube in Figure 4a represents a pixel.

The working method of the digital projection 3D molding device proposed by the present invention is as follows: the ultraviolet light emitted by the LED projection light machine passes through the lens barrel 3 (or the electric control rotary table 2 and the lens barrel 3), the optical plate 4, the transparent quartz glass 5 and the transparent The silicone disc 6 is finally irradiated onto the working surface 7. During the working process, the LED projection optical machine 1 is fixed, and the electronically controlled rotary table 2 drives the optical plate 4 to rotate at a high speed, thereby realizing the offset of the ultraviolet light. The brightness of the pixel in a given direction is integrated in the angle, and according to the angle The relationship between the angular velocity of the rotation of the optical plate 4 and the exposure time, by changing the exposure time to realize the blurring of pixels, is reflected in the homogenization of step lines and zigzag lines in 3D printing molding, and improves the molding accuracy.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-mentioned embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A digital projection 3D molding device, characterized in that, comprising: a projection device, a rotating device and a light-emitting assembly; Wherein, the rotating device can drive the light emitting component to rotate; The light output component includes a lens barrel and an optical plate, the light output surface of the lens barrel is an inclined plane, and the optical plate is fixedly arranged on the inclined surface of the lens barrel; The light emitted by the projection device exits the optical plate after passing through the lens barrel or the rotating device and the lens barrel. 2. The digital projection 3D molding device according to claim 1, wherein the inclination angle of the optical plate relative to the plane perpendicular to the axis of the lens barrel is equal to the incident angle when the light emitted by the projection device enters the optical plate . 3. The digital projection 3D modeling device according to claim 2, wherein the inclination angle of the optical plate is set according to the pixel size projected by the projection device. 4. The digital projection 3D molding device according to claim 3, wherein the projection device is an LED projection light machine, and the light emitted by the projection device is ultraviolet light. 5. The digital projection 3D forming device according to claim 4, characterized in that the digital projection 3D forming device further comprises transparent quartz glass, and the transparent quartz glass window is arranged on the side of the optical plate away from the projection device. 6. The digital projection 3D molding device according to claim 5, characterized in that the digital projection 3D molding device also includes a transparent silica gel disc and a working surface, the transparent silica gel disc is arranged on the side of the transparent quartz glass window away from the projection device, and the working surface Placed on a transparent silica gel plate; the ultraviolet light output by the LED projection light machine passes through the optical plate, transparent quartz glass window and transparent silica gel plate in turn, and irradiates on the working surface; the rotation of the rotating device drives and controls the rotation of the lens barrel and the optical plate , so as to achieve rotational exposure for each pixel in the projection space, and then realize the integral of the angle in the image space, and produce a smoothing effect. 7. The digital projection 3D molding device according to any one of claims 4 to 6, characterized in that the offset of the ultraviolet light emitted by the LED projection light machine in the optical flat plate Wherein, n is the refractive index of the optical flat plate, i ₁ is the incident angle of ultraviolet light incident on the optical flat plate, unit is rad, the size of this incident angle is equal to the described inclination angle of the optical flat plate, h is the thickness of the optical flat plate. 8. The digital projection 3D molding device according to claim 7, wherein the luminous intensity per unit projected area is equal to the luminous intensity of the microfacets around a certain point on the luminous surface divided by the luminous intensity of the microfacets in a given direction. The projected area perpendicular to the given direction, that is: Among them, α is the angle of the offset center of the main ray, ω is the angular velocity of the optical plate rotation, I is the projected luminous intensity of the LED projection light machine, L is the luminous intensity on the projected area, and s _n is the projection perpendicular to the given direction area; that is, the total luminance on a pixel is Wherein α=0～2π, the unit of brightness is candela/ ^m2 . 9. The digital projection 3D molding device according to any one of claims 1 to 6, 8, characterized in that the rotating device is an electronically controlled rotary table, and the rotation of the electronically controlled rotary table drives and controls the lens barrel and optical The rotation of the plate. 10. The digital projection 3D modeling device according to claim 1, characterized in that the projection device is arranged below, above, left or right of the rotating device, and correspondingly, the light emitted by the projection device is from bottom to top, Project from top to bottom, left to right, or right to left.