CN112026174B

CN112026174B - Device and method for improving 3D printing precision by using DMD dynamic exposure

Info

Publication number: CN112026174B
Application number: CN202010886150.2A
Authority: CN
Inventors: 陈修涛
Original assignee: Hefei Zhongqun Photoelectric Technology Co ltd
Current assignee: Hefei Zhongqun Photoelectric Technology Co ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2023-04-28
Anticipated expiration: 2040-08-28
Also published as: CN112026174A

Abstract

A method for improving 3D printing precision by using DMD dynamic exposure comprises S1, assembling a system; s2, adjusting the angle of the DMD on the portal frame; s3, the DMD control and data processing system cuts and fills the data of the bottommost layer of the 3D model to be printed stored in the system, then sends the data to the DMD, and the DMD transfers the data corresponding to the bottommost layer to the photosensitive material of the workbench and solidifies the data; s4, increasing the distance between the workbench and the DMD to be a first unit distance D1, and horizontally moving the workbench and/or the DMD to deviate a second unit distance D2; the DMD control and data processing system controls the data model to be printed stored in the system to move upwards by a first unit distance D1 in the height direction, cuts and fills the data at the height, sends the data to the DMD, and transfers the obtained data to a photosensitive material of a workbench and solidifies the data; s5, the step S4 is circulated until the whole 3D printing piece is exposed. The invention can produce printing effect with higher precision by moving the printing piece to DMD lens of different rows.

Description

Device and method for improving 3D printing precision by using DMD dynamic exposure

Technical Field

The invention relates to the technical field of 3D printing, in particular to a device and a method for improving 3D printing precision by using DMD dynamic exposure.

Background

With the development of intelligent manufacturing technology, rapid molding of a die or direct printing of parts is called as a hot spot of the current intelligent manufacturing research, the DMD-based 3D printing technology is an important technical scheme in 3D printing, and has the advantages of high printing speed and high precision, but the precision requirement of the 3D printing is continuously improved, the common 3D printing precision cannot meet the requirement, and the method provided by the invention is a method for improving the 3D printing precision of the DMD.

In 3D printing of small-size parts, in the currently used DMD printing, the workbench only moves up and down along the Z axis to change the height of the printed object, so that the positions of each lens on the DMD and the imaging adhesive surface are relatively static, the printing precision depends on the size of the light spot of each lens on the imaging adhesive surface, and if the printing precision is to be improved, the optical magnification of the lens must be reduced, and the problem brought by reducing the optical magnification is that the printing area is reduced.

Disclosure of Invention

In order to achieve the purpose of improving the printing precision of small-sized parts without reducing the printing area, the invention provides a device and a method for improving the 3D printing precision by using DMD dynamic exposure. The invention adopts the following technical scheme:

a method for improving 3D printing accuracy using DMD dynamic exposure, comprising the steps of:

s1, assembling a system; the method comprises the steps that light beams emitted by a laser are made to enter an illuminating lens after passing through an optical fiber, a point light source is changed into a uniform surface light source, the surface light source irradiates on a DMD, light emitted by the DMD irradiates on a workbench through an imaging lens, and the workbench is positioned on the focal plane of the DMD;

s2, adjusting the DMD on the portal frame to enable the direction of relative horizontal movement of the workbench and the DMD to form a set angle with the image formed by the DMD

S3, the DMD control and data processing system cuts and fills the data of the bottommost layer of the 3D model to be printed stored in the system, then sends the data to the DMD, and the DMD transfers the data corresponding to the bottommost layer to the photosensitive material of the workbench and solidifies the data;

s4, increasing the distance between the workbench and the DMD until the solidified upper surface is positioned on the focal plane of the DMD, wherein the increased distance is the first unit distance D1, and horizontally moving the workbench and/or the DMD to enable the projection of the DMD projection focal plane on the workbench to deviate from the projection after the last solidification by the second unit distance D2; the DMD control and data processing system controls the data model to be printed stored in the system to move upwards in the height direction until the moving distance is the same as the first unit distance D1 of the downward movement of the workbench, the data at the height is cut and filled and sent to the DMD, and the DMD transfers the obtained data to the photosensitive material of the workbench and solidifies;

s5, the step S4 is circulated until the whole 3D printing piece is exposed.

The invention has the advantages that:

(1) The imaging of the DMD forms a set angle with the direction of the relative horizontal movement of the workbench and the DMD and the workbench, and each time the DMD pattern is replaced, the pattern generates displacement in the horizontal direction and the vertical direction, and the displacement is smaller than the distance between two adjacent lenses of the DMD, so that the printing effect with higher precision can be generated by moving the printing piece to the lenses of different rows in the DMD.

(2) According to the device, the driving device is arranged below the workbench to drive the workbench to move obliquely downwards, so that the driving quantity is saved.

Drawings

Fig. 1 is a block diagram of the present system.

Fig. 2 is a schematic diagram of a horizontal coordinate system in which the DMD mounting direction is parallel to the table.

Fig. 3 shows the states of the DMD mirrors in the horizontal coordinate system.

FIG. 4 is a schematic view of a DMD mounted 45 print a 45 straight line

The meaning of the reference symbols in the figures is as follows:

1-laser 2-optical fiber 3-illumination lens 4-DMD control and data processing system

5-flexible flat cable 6-DMD 7-imaging lens 8-portal frame 9-workbench

Detailed Description

A method of using a DMD dynamic exposure to enhance 3D printing accuracy, comprising the steps of:

s1, assembling a system; as shown in fig. 1, a laser 1 in the system is incident to an illumination lens 3 through an optical fiber 2, the illumination lens 3 changes a point light source into a uniform surface light source to irradiate on a DMD6 on a portal frame 8, light emitted by the DMD6 is irradiated on a workbench 9 through an imaging lens 7, and a DMD control and data processing system 4 is in signal connection with the DMD6 through a flexible flat cable 5;

s2, adjusting the DMD6 on the portal frame 8, and enabling the image formed by the DMD6 to form a set angle with the horizontal moving direction of the workbench 9. The imaging of the DMD6 and the horizontal movement direction of the table 9 are shown in fig. 2, the invention takes the setting angle of 45 ° as an example, the optical magnification of the lens is 1, the distance between two adjacent lenses in the DMD6 is 10.8 μm, the left square frame in fig. 2 is the DMD6, the right side is the horizontal coordinate system parallel to the table 9, wherein the DMD6 has 45 °, and the right side in fig. 3 is the component of each lens on the DMD6 in two directions of the horizontal coordinate system.

S3, the DMD control and data processing system 4 cuts and fills the bottommost data of the 3D model data to be printed stored in the system, and then sends the data to the DMD6, and the DMD6 transfers the bottommost obtained data to a photosensitive material of the workbench 9;

s4, the workbench 9 moves downwards by a first unit distance D1

Wherein M represents the magnification of the imaging lens 7, +.>

To set the angle, the second unit distance D2 is moved in the horizontal direction at the same time

S represents the single lens size of DMD6, and in summary, the first cell distance d1=10.8×sin (45) and the second distance d2=s10.8×sin (45) are used in this application. As shown in fig. 4, the black part is a structure after the lens group a formed by the continuous lenses at the adjacent diagonal angles on the DMD6 is cured on the photosensitive material for the previous time, and the white part is a structure after the DMD6 wafer group a is cured on the photosensitive material after moving the distance D2, and it can be seen that this way, the error of the 3D printing edge can be reduced.

The DMD control and data processing system 4 stores a data model to be printed in the system, the data model to be printed moves upwards in the height direction, the moving distance is the same as the first unit distance D1 of the downward movement of the workbench 9, the moving distance in the horizontal direction is the same as the second unit distance D2 of the horizontal movement of the workbench 9, the data of the height is cut and filled and sent to the DMD6, and the DMD6 transfers the data obtained at the bottommost layer to a photosensitive material of the workbench 9; as shown in fig. 3, each time the pattern of the DMD6 is replaced, both directions of the pattern horizontal coordinate system are displaced by one amount, and the displacement amount is smaller than the distance between the adjacent two lenses, so that by moving the print onto the DMD6 lenses of different rows, a printing effect with higher accuracy can be produced. Fig. 3 is a schematic view of the DMD mounted at 45 ° to print a 45 ° line, the saw teeth being apparent when printing the first layer, and the next layer being printed when the stage moves the second unit by a distance D2, the distance being significantly smaller, and thus the printing accuracy being increased.

S5, circulating the step S4, wherein when the exposed pattern is translated to be close to the edge of the DMD, the workbench 9 moves downwards by the first unit distance D1, and simultaneously moves horizontally by the second unit distance D2 in the opposite direction, and circulating the step S4 until the whole 3D printing piece is exposed. In this scheme, the method for judging that the exposed pattern shifts close to the edge of the DMD is: let the moving direction of the working table 9 form an included angle with the horizontal plane

The movement distance is L, and the DMD has a maximum imaging size a on a horizontal component with respect to the movement direction of the table 9; the object to be printed has a maximum print size B in this direction, when +.>

When the set value is reached, the edge of the DMD is judged to be close, and the set value is set according to specific conditions.

The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. A method for improving 3D printing accuracy using DMD dynamic exposure, comprising the steps of:

s1, assembling a system; the method comprises the steps that light beams emitted by a laser (1) are made to enter an illumination lens (3) after passing through an optical fiber (2), point light sources are changed into uniform area light sources, the area light sources are irradiated onto a DMD (6), light emitted by the DMD (6) is irradiated onto a workbench (9) through an imaging lens (7), and the workbench (9) is located on the focal plane of the DMD (6); a driving mechanism for enabling the workbench (9) to move obliquely downwards is arranged below the workbench (9);

s2, adjusting a portal frame(8) A DMD (6) on the upper surface, wherein the direction of relative horizontal movement of the working table (9) and the DMD (6) forms a set angle with the image formed by the DMD (6)

The imaging of the DMD forms a set angle with the direction of the relative horizontal movement of the workbench and the DMD and the workbench, and each time the DMD pattern is replaced, the pattern generates displacement in the horizontal direction and the vertical direction, and the displacement is smaller than the distance between two adjacent lenses of the DMD;

s3, the DMD control and data processing system (4) cuts and fills the data of the bottommost layer of the 3D model to be printed stored in the system, and then sends the data to the DMD (6), and the DMD (6) transfers the data corresponding to the bottommost layer to a photosensitive material of the workbench (9) and solidifies the data;

s4, increasing the distance between the workbench (9) and the DMD (6) until the solidified upper surface is positioned on the focal plane of the DMD (6), wherein the increased distance is a first unit distance D1, and horizontally moving the workbench (9) and/or the DMD (6) to enable the projection of the focal plane projected by the DMD (6) on the workbench to deviate from the projection of the focal plane after the last solidification by a second unit distance D2; the DMD control and data processing system (4) controls a data model to be printed stored in the system to move upwards in the height direction until the moving distance is the same as the first unit distance D1 of the downward movement of the workbench (9), cuts and fills the data at the height, sends the data to the DMD (6), and the DMD (6) transfers the obtained data to a photosensitive material of the workbench (9) and solidifies the data;

s5, the step S4 is circulated until the whole 3D printing piece is exposed.

2. The method for improving 3D printing accuracy using DMD dynamic exposure as claimed in claim 1, wherein the set angle in step S2 is

The twiddle factor is a positive integer.

3. A method for improving 3D printing accuracy using DMD dynamic exposure as claimed in claim 2 wherein in step S4 the second cell distance is

S denotes a single lens size of the DMD (6), M denotes a magnification of the imaging lens (7), tan θ=d1/D2.

4. A method for improving 3D printing accuracy using DMD dynamic exposure as claimed in claim 3 wherein in step S4 the first cell distance d1=sχm x sin (θ).

5. The method for improving 3D printing accuracy using DMD dynamic exposure as claimed in claim 4, wherein a ratio of a component in a horizontal direction to a component in a vertical direction in a diagonal direction is D1/D2.