WO2019127454A1

WO2019127454A1 - Step-by-step splicing type 3d printing system and printing method

Info

Publication number: WO2019127454A1
Application number: PCT/CN2017/120115
Authority: WO
Inventors: 王焱华; 冯玉林; 何贺敬; 黄立; 赵�卓; 贺晓宁; 方绚莱
Original assignee: 深圳摩方新材科技有限公司
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2019-07-04

Abstract

Provided in the present invention are a step-by-step splicing type 3D printing system and a printing method, the system comprising a control system and a 3D printer, wherein the control system is in communication connection to the 3D printer; the 3D printer comprises a fixing platform as well as a lens fixing column and a printing mechanism which are arranged at the upper end of the fixing platform; the lens fixing column is provided with a photoetching lens which corresponds to the position of the printing mechanism; an XY-axis movement platform is disposed between the printing mechanism and the fixing platform; and the XY-axis movement platform comprises an X-axis movement mechanism and a Y-axis movement mechanism. The XY-axis movement platform is provided, so that the printing breadth may be increased in a step-by-step splicing mode while high printing precision may be guaranteed, and splicing errors in the splicing process may be effectively resolved.

Description

Stepping and splicing 3D printing system and printing method

Technical field

The present invention relates to the field of 3D printing, and in particular, to a step-splicing 3D printing system and a printing method.

Background technique

Currently, digital micromirror devices (DMDs) are commonly used in surface projection micro-stereolithography (DLP) 3D printing technology. The DMD microlens matrix is used to provide an exposed image. Each microlens of the DMD microlens matrix is typically 7-10 um in size, and the accuracy of the printing depends on the size of the microlenses. In the face projection micro-stereolithography (DLP) 3D printing technology, in order to further high precision to the sub-micron level, the DMD image is generally reduced by optical design, that is, the image reflected by the DMD is performed by using the projection objective lens. Zoom out to achieve the purpose of improving printing accuracy. Since the accuracy of the image is improved after the overall reduction of the image, the single-printing format is also reduced, that is, the printing accuracy and the format cannot be simultaneously achieved.

Through the optical path design, after the projection objective lens is reduced, the printed image will be reduced, for example, 1280*800 pixels DMD, DMD micro lens size is 7.6*7.6um, DMD overall size is about 9.6*6cm, using lateral magnification β= The projection objective of 0.1 is miniature, and the single pixel size can be increased to 0.76 um, but the print format will be reduced to 0.96*0.6 cm. That is, after the printing accuracy is improved, the printing width is reduced from 9.6*6 cm to 0.96*0.6 cm.

In order to improve the printing format on the premise of satisfying the accuracy, the prior art CN201520983708.3 proposes to use a plurality of DLP optical machines to combine, but the method is costly, and the relative positions between the optical machines need to be accurately adjusted and Fixed, the use of flexibility is not good.

technical problem

Type the technical problem description paragraph here.

Technical solution

In order to solve the problems in the prior art, the present invention provides a step-and-stitch 3D printing system and a printing method.

The invention provides a step-splicing 3D printing system, comprising a control system and a 3D printer, the control system is communicatively connected to the 3D printer, the 3D printer comprises a fixed platform and a lens fixing column disposed at an upper end of the fixed platform And a printing mechanism, the lens fixing column is provided with a lithography lens corresponding to the position of the printing mechanism, and an XY axis motion platform is disposed between the printing mechanism and the fixed platform, and the XY axis motion platform includes an X Axis motion mechanism and Y-axis motion mechanism.

As a further improvement of the present invention, the X-axis motion mechanism and the Y-axis motion mechanism are both screw motion mechanisms.

As a further improvement of the present invention, the printing mechanism comprises a connecting plate and a printing platform, a printing platform lifting mechanism and a liquid tank provided on the connecting plate, the printing platform is placed in the liquid tank, the connecting plate Connected to the XY axis motion platform.

As a further improvement of the present invention, the liquid tank is further provided with a liquid tank lifting mechanism.

As a further improvement of the present invention, the printing platform lifting mechanism is disposed on one side of the liquid tank and fixed on the connecting plate.

The invention also discloses a printing method based on the above stepping splicing 3D printing system, comprising the following steps:

S1: The control system divides the printed image into a plurality of sub-pictures according to the size of the picture printed by each layer;

S2: determining whether the pixel size of the sub-picture is smaller than the DMD lens pixel, if yes, performing reverse padding so that the sub-picture is located at the center of the DMD lens pixel picture and performing step S5; if not, performing the next step;

S3: increasing the number of stitching times in the X-axis or Y-axis direction by the pixel sub-picture larger than the DMD lens and cutting it into a new sub-picture;

S4: determining whether the pixel size of the new sub-picture is smaller than the DMD lens pixel, if yes, performing reverse padding so that the sub-picture is located in the DMD lens pixel picture center and performing step S5, if not, executing step S3;

S5: performing grayscale processing on the edge of the DMD lens pixel sub-picture and adjusting the size of the splicing;

S6: adjusting the motion compensation parameters of the X axis and the Y axis according to the effect of printing the sample;

S7: Projecting one by one according to each of the cut word pictures and moving the stitching printing step by step in a certain direction and order on the X-axis and the Y-axis.

As a further improvement of the present invention, the printed picture is divided into integer multiples of the sub-picture in the step S1.

As a further improvement of the present invention, in the step S2, the sub-picture smaller than the DMD lens pixel is back-filled and its projection format is located at the center of the DMD lens pixel.

As a further improvement of the present invention, the step S5 further includes the following steps:

S51: The X-axis and the Y-axis are finely adjusted after moving to a specified position before each projection.

Beneficial effect

The invention has the beneficial effects that the XY axis motion platform can be set, and the printing width can be increased by stepping and splicing while ensuring high printing precision, and the splicing error in the splicing process can be effectively solved.

DRAWINGS

1 is a schematic structural view of a step-splicing 3D printing system of the present invention;

Figure 2 is a flow chart of the printing method of the present invention;

Figure 3 is a schematic diagram of the stitching in each layer of the printing method of the present invention.

LIST OF REFERENCE NUMERALS 1 - fixed platform; 2 - lens mount; 21 - lithography lens; 3-XY axis motion platform; 41 - connection plate; 42 - printing platform lifting mechanism; 43 - liquid tank; 44 - printing platform.

BEST MODE FOR CARRYING OUT THE INVENTION

The description of the preferred embodiment of the invention is entered here.

Embodiments of the invention

As shown in FIG. 1 , the present invention discloses a step-splicing 3D printing system including a control system and a 3D printer. The control system is communicatively coupled to the 3D printer, and the 3D printer includes a fixed platform 1 and is disposed in the a lens fixing column 2 and a printing mechanism at an upper end of the fixed platform 1, the lens fixing column 2 is provided with a lithography lens 21 corresponding to the position of the printing mechanism, and XY is arranged between the printing mechanism and the fixed platform 1. An axis motion platform 3, the XY axis motion platform 3 includes an X-axis motion mechanism and a Y-axis motion mechanism.

The X-axis motion mechanism and the Y-axis motion mechanism are both screw motion mechanisms.

The printing mechanism includes a connecting plate 41, a printing platform 44 disposed on the connecting plate 41, a printing platform lifting mechanism 42 and a liquid tank 43. The printing platform 44 is placed in the liquid tank 43, the connecting plate 41 is coupled to the XY axis motion platform 3.

The liquid tank 43 is further provided with a liquid tank lifting mechanism, which can adjust the height of the liquid tank to facilitate liquid level replenishment.

The printing platform elevating mechanism 42 is disposed on one side of the liquid tank 43 and is fixed to the connecting plate 41.

The printed picture is divided into integer multiples of the sub-picture in the step S1.

In the step S2, the sub-picture smaller than the DMD lens pixel is back-filled and its projection format is located at the center of the DMD lens pixel.

The step S5 further includes the following steps:

In each layer of printing, after cutting the printed image, the pixel size of each sub-picture is the pixel size of the DMD, for example, 1280*800 pixels. During the printing process, each sub-picture is printed along the X first. The axis moves 1280 pixels in steps, and then moves 800 pixels along the Y axis. As shown in FIG. 3, 1-16 performs projection exposure in sequence to print a picture of 5120*3200 pixels. A larger image of the print format, and so on, can increase the number of stitches for larger format printing.

At the same time, for a picture whose pixel size is not an integer multiple of 1280*800, the number of times of splicing in the X direction and the Y direction can be appropriately selected, so that the size of the sub-picture after cutting is less than 1280*800 pixels, and the pixel size is less than 1280*800 pixels before printing. The sub-picture is reverse-filled so that the sub-picture is projected at the center of the entire projection area, thus ensuring the integrity of the splicing. For example, if the image to be printed is 2000*1200 pixels, after cutting, the actual projection area of each printed sub-picture has a pixel size of 1000*600 pixels. After the reverse filling, the sub-picture is in the entire projection format 1280*. In the center of the 800 area, this step can effectively reduce the stitching error and provide printing accuracy.

In order to correct the motion errors of the X-axis and the Y-axis, reduce the stitching error, and further improve the printing precision, the present invention provides a method for eliminating the stitching error. For example, the maximum projected size of a single plane of a device is 1280*800 pixels, and the single pixel size is a fixed value, for example, 0.76 um.

If you need to increase the printing format while ensuring the printing accuracy, for example, to print a picture of 2560*1600 pixels, you need to splicing 4 times, and the format of each print is still 1280*800 pixels. After printing a single frame, move it. X-axis and Y-axis to the specified position, wait for a period of time to stabilize the liquid level after waiting for the X-axis and Y-axis to the specified position, and then print another 1280*800 pixel image, and pixels can be set between adjacent print formats. The amount of overlap size, and the gray value of the overlapping part of the picture to adjust the size of the seam at the splicing, according to the printing process effect, gradually adjust the pixel size and gray value of the overlapping part, the size of the seam at the splicing can be adjusted to 1- Within 2um.

In addition, during the step stitching process, the X-axis and Y-axis motions are generally not completely vertical, and have a certain tilt angle, such as 0.001-0.002 degrees. For a high-precision 3D printing system, such a small tilt angle has been affected. High-precision splicing process, in order to eliminate the splicing error caused by the tilt angle of such a small angle, by setting the printing process, before each projection, the X-axis and the Y-axis are finely adjusted after being moved to the designated position, and the compensation is performed. Error due to tilting of the X and Y axes. Through the test printing process, the stitching compensation parameters are continuously adjusted to eliminate the error caused by the X-axis and Y-axis motions with a certain tilt angle.

The invention can realize the printing width by step splicing while ensuring high printing precision; the splicing error in the splicing process can be effectively solved, and the high-precision and large-format 3D printing can be realized at the same time; the splicing error is reduced One of the ways is to reversely fill the cut sub-picture, so that one of the ways to reduce the stitching error of the sub-picture in the center of the projection web is to reasonably design the gray scale size and overlapping pixel size of the overlapping overlapping pixels; One of the error modes is to properly adjust the compensation of the X-axis and the Y-axis to reduce the error caused by the tilting of the X-axis and the Y-axis.

The above is a further detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It will be apparent to those skilled in the art that the present invention may be made without departing from the spirit and scope of the invention.

Industrial applicability

Type the industrial usability description paragraph here.

Sequence table free content

Type the sequence table free content description paragraph here.

Claims

A step-splicing 3D printing system, comprising: a control system and a 3D printer, wherein the control system is communicatively coupled to the 3D printer, the 3D printer comprising a fixed platform and a lens fixing column disposed at an upper end of the fixed platform And a printing mechanism, the lens fixing column is provided with a lithography lens corresponding to the position of the printing mechanism, and an XY axis motion platform is disposed between the printing mechanism and the fixed platform, and the XY axis motion platform includes an X Axis motion mechanism and Y-axis motion mechanism.
The step-and-stitch 3D printing system according to claim 1, wherein the X-axis motion mechanism and the Y-axis motion mechanism are both screw motion mechanisms.
The step-splicing 3D printing system according to claim 1, wherein the printing mechanism comprises a connecting plate, a printing platform provided on the connecting plate, a printing platform lifting mechanism and a liquid tank, wherein the printing platform is disposed The connecting plate is connected to the XY axis moving platform in the liquid tank.
The step-and-stitch 3D printing system according to claim 3, wherein the liquid tank is further provided with a liquid tank lifting mechanism.
The step-stitching 3D printing system according to claim 1, wherein the printing platform lifting mechanism is disposed on one side of the liquid tank and fixed on the connecting plate.
A printing method for a step-and-stitch 3D printing system according to any one of claims 1 to 5, comprising the steps of:

S1: The control system divides the printed image into a plurality of sub-pictures according to the size of the picture printed by each layer;

S2: determining whether the pixel size of the sub-picture is smaller than the DMD lens pixel, if yes, performing reverse padding so that the sub-picture is located at the center of the DMD lens pixel picture and performing step S5; if not, performing the next step;

S3: increasing the number of stitching times in the X-axis or Y-axis direction by the pixel sub-picture larger than the DMD lens and cutting it into a new sub-picture;

S4: determining whether the pixel size of the new sub-picture is smaller than the DMD lens pixel, if yes, performing reverse padding so that the sub-picture is located in the DMD lens pixel picture center and performing step S5, if not, executing step S3;

S5: performing grayscale processing on the edge of the DMD lens pixel sub-picture and adjusting the size of the splicing;

S6: adjusting the motion compensation parameters of the X axis and the Y axis according to the effect of printing the sample;

S7: Projecting one by one according to each of the cut word pictures and moving the stitching printing step by step in a certain direction and order on the X-axis and the Y-axis.
The step stitching printing method according to claim 6, wherein the printed picture is divided into integer multiples of the sub-picture in the step S1.
The step stitching printing method according to claim 6, wherein in the step S2, the sub-picture smaller than the DMD lens pixel is back-filled and the projection image is located at the center of the DMD lens pixel.
The step splicing printing method according to claim 6, wherein the step S5 further comprises the following steps:

S51: The X-axis and the Y-axis are finely adjusted after moving to a specified position before each projection.