CN115157652A

CN115157652A - 3D printing method, printer and storage medium

Info

Publication number: CN115157652A
Application number: CN202210729679.2A
Authority: CN
Inventors: 王志刚; 马睿; 郝鹏
Original assignee: Kocel Intelligent Machinery Ltd
Current assignee: Kocel Intelligent Machinery Ltd
Priority date: 2022-06-27
Filing date: 2022-06-27
Publication date: 2022-10-11

Abstract

The invention relates to a 3D printing method, a printer and a storage medium, wherein the printing method comprises the following steps: printing each layer of a product to be printed in an XY plane in a set printing area; before printing is started, rotating the printing head and/or the three-dimensional model to enable the printing head and/or the three-dimensional model to form an included angle alpha (0 degrees & lt alpha & lt 90 degrees) with the X axis; wherein the X-axis direction is the scanning direction of the print head; when the printing is carried out layer by layer, the printing head carries out layer by layer dislocation on n jet holes (n is more than or equal to 1) in the Y-axis direction for printing. Aiming at the surface quality defect of a product caused by abnormal jet ink of a jet orifice, the 3D printing method rotates the printing head and/or the three-dimensional model by a certain angle before printing on the premise of not changing the spray head, so that the printing head and/or the three-dimensional model forms a certain included angle alpha (alpha is more than 0 degree and less than 90 degrees) with the X axis, thereby leading the YZ plane of the printed product to adopt different jet orifices for ink jet, and further infinitely reducing the defect of the YZ plane of the product caused by abnormal jet ink of the jet orifice.

Description

3D printing method, printer and storage medium

Technical Field

The invention relates to the technical field of 3D printing, in particular to a Z-axis double-telescopic truss robot.

Background

The 3DP (Three-dimensional printing) technology is also called powder bonding Three-dimensional printing or micro-droplet jetting technology, and the technology is that a Three-dimensional model is processed into two-dimensional slice information according to a certain thickness, then a powder spreader spreads a layer of powder, an ink jet printing head carries out ink jet at a specific position according to the two-dimensional slice information of the current layer, a lifting platform descends one layer of thickness, and the next time of powder spreading, ink jet and lifting are carried out in a circulating mode until the printing of the whole Three-dimensional model is completed.

The printing head is a key core component of droplet ejection 3D printing, and in order to increase the width of a single scan, one printing head is generally formed by splicing a plurality of nozzles, which include thousands or tens of thousands of orifices. The slice profile of each layer of the different models is uncertain, and in order to ensure that the ink ejection profile of each layer is normal, it is necessary to ensure that each orifice is properly ejected, which is often not possible in actual printing.

Patent document CN 112743836A discloses a method for printing patterns in a staggered manner, that is, after the pattern spraying and printing of each layer of print head is completed, the print head is moved in a random manner, and then the next layer of print head is printed. The method disclosed by the patent can avoid product defects caused by jet hole defects to a certain extent, but no matter the jet hole ink jet positions are overlapped or lost caused by jet hole splicing deviation, and the abnormal ink jet phenomena such as frame loss or oblique jet caused by jet hole blockage exist, the following determination is made: because the existing dislocation method only reduces the probability of occurrence of problems and cannot completely avoid defects caused by abnormal ink jet, when the abnormal ink jet occurs on a certain layer or several layers of YZ surfaces of a product, the YZ surfaces of the printed product still have obvious defects to influence the surface quality of the formed product.

As shown in fig. 1-2, fig. 1 is a schematic diagram of normal ink ejection through each nozzle, fig. 2 is a schematic diagram of XY coordinate system, and compared with fig. 1, 22 and 23 are theoretical ink ejection positions corresponding to the nozzle 1 and the nozzle 7, respectively, and when the nozzle 1 and the nozzle 7 on the nozzle 20 lose frames and perform oblique ejection, and the

corresponding positions

22 and 23 cannot eject ink normally, the layer prints the position with a defect. As shown in fig. 3, which is a schematic view in an XY coordinate system, 33 is a theoretical ink ejection position corresponding to the nozzle hole 1, and since the nozzle hole 1 on the head 30 ejects ink obliquely, the layer of printing ink is ejected onto the position 32, and the theoretical position 33 cannot eject ink normally.

As shown in fig. 4, which is a schematic view in YZ coordinate system, in the height direction of layer-by-layer accumulation, from bottom to top, layers 1 to 12 are sequentially formed, wherein the

marks

41, 43 and 46 are respectively the 11 th, 7 th and 2 th layers of ink jet, and ink jet abnormality corresponds to the nozzle hole 1 and the nozzle hole 7 described in fig. 2, wherein the

marks

42 and 45 are respectively the 9 th and 5 th layers of ink jet, and ink jet abnormality corresponds to the nozzle hole 1 described in fig. 3. When the abnormal ink jet point appears in the middle of the product, only the abnormal ink jet (such as the abnormal ink jet of the 7 th jet orifice of 41 marked in fig. 4) appears at the position of the abnormal jet orifice of the current layer, that is, an ink jet blank line appears along the X direction. However, when the theoretical ink ejection position of the abnormal ink ejection orifice occurs on the Y surface, the abnormal ink ejection positions such as orifice frame loss, oblique ejection and the like all occur on the current Y surface layer indicated as 41, 42, 43, 45 and 46 in fig. 4, and then concave-convex defects (for example, the first layer printed Y surface is normal, the second layer printed Y surface is concave, the third fourth layer printed Y surface is normal, and the fifth layer printed Y surface is convex) occur between the Y surface layer and the layer of the final molded product, which affects the product quality and necessitates replacement of the ejection head.

Disclosure of Invention

Therefore, it is necessary to provide a 3D printing method for solving the problem of the surface quality defect of the product caused by abnormal ink ejection through the nozzle hole in the prior art.

A3D printing method, in the set printing area, print in XY plane to wait to print each layer of the products;

before printing is started, rotating the printing head and/or the three-dimensional model to enable the printing head and/or the three-dimensional model to form an included angle alpha (0 degrees < alpha < 90 degrees) with the X axis; wherein the X-axis direction is the scanning direction of the print head;

when the printing is carried out layer by layer, the printing head carries out layer by layer dislocation on n jet holes (n is more than or equal to 1) in the Y-axis direction for printing.

Further, the included angle α is less than 45 °.

Further, while each layer is printed, the print head is scanning in the X-axis direction while the print head is also stepping slowly along the Y-axis.

Further, the print head steps forward along the Y axis a distance of 1 orifice for every 1mm of scan in the X axis direction.

Further, the print head is cyclically stepped in the forward and reverse directions along the Y axis while the print head is scanned in the X-axis scanning direction.

Further, while the printing head scans in the X-axis direction, the printing head firstly steps by one nozzle hole distance each time along the forward direction of the Y-axis until the maximum set nozzle hole number P is reached along the forward direction of the Y-axis, and then the printing head steps by one nozzle hole distance each time along the reverse direction of the Y-axis until the maximum set nozzle hole number P is reached along the reverse direction of the Y-axis, and the steps are repeated until the current layer printing is completed.

A printer comprising a memory, a processor and a computer program stored in said memory and executable on said processor, said processor executing said computer program to implement the steps of the method as described above in real time.

A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the above-mentioned method steps.

A printed product obtained by using the printing method or the printer or the readable storage medium.

According to the 3D printing method, the printer and the storage medium provided by the invention, aiming at the surface quality defect of a product caused by abnormal jet orifice ink injection, on the premise of not changing a spray head, the printing head and/or the three-dimensional model are rotated by a certain angle before printing is started, so that the printing head and/or the three-dimensional model and an X axis form a certain included angle alpha (alpha is more than 0 degree and less than 90 degrees), and thus different jet orifices are adopted for ink injection on a YZ plane of a printed product, and the defect of the YZ plane of the product caused by abnormal jet orifice ink injection is further infinitely reduced. When the printing is carried out layer by layer, the printing head is enabled to stagger n jet holes (n is more than or equal to 1) layer by layer in the Y direction for printing, and the continuous defects of the YZ surface of the product are further prevented. And when each layer is printed, the printing head scans in the X-axis direction and simultaneously slowly steps along the Y-axis, so that the defects of YZ planes caused by abnormal ink jetting of the jet holes are further reduced.

Drawings

FIG. 1 is a schematic view of a normal ink jet of an XY plane nozzle of the present invention;

FIG. 2 is a schematic view of the ink jet system of the present invention with an XY plane nozzle in abnormal 1 state;

FIG. 3 is a schematic view of the abnormal condition of the XY plane nozzle 2 according to the present invention;

FIG. 4 is a schematic view of abnormal YZ height direction nozzles according to the present invention;

FIG. 5 is a schematic view of an abnormal XY plane nozzle of the present invention;

FIG. 6 is a schematic view of the ink jet system with abnormal nozzle holes when the XY plane three-dimensional model is tilted;

FIG. 7 is a flow chart of the Y-axis stepping control of the printhead of the present invention;

FIG. 8 is a schematic view of the print head of the present invention being cycled in the Y-axis direction;

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "left," "right," "top," "bottom," "top," and the like are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The following describes the 3D printing method, the printer, and the storage medium with reference to specific embodiments to further understand the inventive concepts of the 3D printing method, the printer, and the storage medium, where the 3D printing method includes: printing each layer of a product to be printed in an XY plane in a set printing area; before printing is started, rotating the printing head and/or the three-dimensional model to enable the printing head and/or the three-dimensional model to form an included angle alpha (0 degrees < alpha < 90 degrees) with the X axis; wherein the X-axis direction is the scanning direction of the print head; when the printing is carried out layer by layer, the printing head carries out layer by layer dislocation on n jet holes (n is more than or equal to 1) in the Y-axis direction for printing.

A printer comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the steps of the above method.

A computer-readable storage medium having stored thereon a computer program for execution by a processor to perform the steps of implementing the method as described above.

A printed product obtained using a printing method as described above or a printer as described above or a readable storage medium as described above.

According to the 3D printing method, the printer and the storage medium provided by the invention, aiming at the surface quality defect of a product caused by abnormal jet orifice ink injection, on the premise of not changing a spray head, the printing head and/or the three-dimensional model are rotated by a certain angle before printing is started, so that the printing head and/or the three-dimensional model and an X axis form a certain included angle alpha (alpha is more than 0 degree and less than 90 degrees), and thus different jet orifices are adopted for ink injection on a YZ plane of a printed product, and the defect of the YZ plane of the product caused by abnormal jet orifice ink injection is further infinitely reduced. When the printing is carried out layer by layer, the printing head is enabled to stagger n jet holes (n is more than or equal to 1) layer by layer in the Y direction for printing, and the continuous defects of the YZ surface of the product are further prevented. And when each layer is printed, the printing head scans in the X-axis direction and also slowly steps along the Y-axis, so that the defects of YZ plane caused by abnormal ink jetting of the jet holes are further reduced.

The first embodiment:

as shown in fig. 5, the print head 50 has orifices 1-12 in sequence from top to bottom, and the current printed layer print image 51 is a rectangle, wherein the length in the X direction is m, the length in the Y direction is n, the white circles are abnormal ink ejection dots 52, the black dots represent normal ink ejection, and the X axis direction is the scanning direction of the print head. The abnormal ink jetting point 52 corresponds to a theoretical ink jetting position of the third nozzle hole 3, assuming that the maximum molding size in the X direction is M and the maximum molding size in the Y direction is N, the third nozzle hole 3 does not jet ink at the position due to frame dropping or writing jetting, and is displayed in white, when the layer is printed, the theoretical ink jetting position corresponding to the third nozzle hole 3 does not jet ink along the whole X axis direction, that is, the YZ surface of the layer is abnormal in ink jetting, and the length is M. If the product is in the maximum molding size, the length of the YZ surface defect is M, and since the print head is randomly displaced along the Y-axis direction during layer-by-layer printing, that is, the nozzle is randomly displaced along the Y-axis direction, the multi-layer printed product may have the concave-convex defect shown in fig. 4 on the YZ surface.

In the first embodiment, as shown in fig. 6, assuming that the three-dimensional model is placed at an angle α with respect to the X-axis, and the X-axis direction is the scanning direction of the print head, the image of the current layer is also at an angle α with respect to the X-axis, the print head 60 has a plurality of nozzles, wherein the nozzles are marked as a second nozzle 61, a third nozzle 62, and a fourth nozzle 63, the image 65 of the current printing layer is the same as the image shown in fig. 5, the length is m, the width is n, and several abnormal ink ejection dots 64 exist on the image 65 of the current printing layer. As shown in fig. 6, before printing is started, the three-dimensional model is rotated by a certain angle so that the included angle between the three-dimensional model and the X axis is α, wherein 0 ° < α < 90 °, and preferably α < 45 °, so that the length of each layer image projected in the X axis direction is mcos α + ncos α, and the width projected on the Y axis is msin α + ncos α, and at the same time, only the third nozzle hole 3 originally participates in ink ejection in the YZ plane of the current layer in fig. 5, and ink ejection from the second nozzle hole 61, the third nozzle hole 62, and the fourth nozzle hole 63 is performed simultaneously after the three-dimensional model is rotated, that is, when only the rotation angle α of the three-dimensional model is rotated and other conditions are not changed at the time of printing of each layer, defects caused by ink ejection abnormalities such as frame dropping and oblique ejection are reduced to a certain extent. The extent of defect reduction is illustrated by the following example:

assuming that the maximum molding size X direction length M of a certain 3D printer is 1000mm, the Y direction width N is 800mm, the splicing resolution R of a printing head in the Y direction is 300DPI, the placing angle alpha of a three-dimensional model is 5 degrees, if a certain jet hole is defective and the jet hole jets ink just on a YZ plane of the outer surface of a printed product, the defect length of the YZ plane is 25.4/R/sin alpha, namely the defect length is 0.97mm, and when the model is normally placed, the concave-convex defect length caused by abnormal jet ink jetting of the jet hole is 1000mm. And the defect runs through the YZ plane of the whole product of the current layer. Therefore, when the three-dimensional model and the X axis form an included angle of 5 degrees, the defects of the YZ plane of the product are greatly reduced, and the length is only 0.97mm, so that the surface appearance defects of the printed product are greatly reduced, and the appearance is exquisite.

After the image of the current layer is printed, when the next layer is printed, the printing head is staggered by n (n is more than or equal to 1) spray orifices along the Y direction for printing.

The second embodiment:

before printing, the printing head is rotated by a certain angle, so that the printing head forms an angle alpha with the X axis, wherein alpha is less than 45 degrees, the X axis direction is the scanning direction under the condition that the printing head does not rotate, and the printing head scans and prints the current layer along the angle alpha with the X axis angle, so that the effect of reducing the YZ surface defects of the product in the embodiment 1 can be achieved. And the printing head and the three-dimensional model are rotated by the angle alpha simultaneously to print the current layer, so that the YZ plane defect of the product can be reduced.

The third embodiment:

for the abnormal ink jet of the jet orifice, when the current layer is printed, the printing head scans in the X direction and slowly steps in the Y direction. Specifically, in one embodiment, the printhead is positively stepped along the Y-axis by a distance of one orifice per 1mm of scan of the printhead in the X-direction, while ensuring the maximum molding size.

In another embodiment, referring to the flowchart shown in FIG. 7, the print head is cycled in the Y-axis back and forth while scanning in the X-axis. Specifically, as shown in the flowchart of fig. 7, in the case where the maximum molding size is secured, it is assumed that the maximum number of displaced ejection holes when stepping in the Y-axis forward direction and the Y-axis reverse direction is P. The print head was slowly stepped in the Y direction while scanning in the X direction, which determined the length of the YZ plane defect of the product caused by the defective nozzle of the ink jet (assuming the effect of placing the model at an inclination of 5 ° with reference to the first embodiment, d was set to 1 mm), and the distance of the image shift in the Y direction was 0.0847mm in order to keep the image ejected and not misaligned. Every 1mm of scanning distance is arranged in the X-axis direction, the printing head is staggered by the distance of one jet orifice along the Y-axis positive direction at the same time, and the circulation is continued until the set maximum staggered jet orifice number P is reached; then the printing head is shifted by a distance of one jet orifice each time along the Y-axis reverse direction, the printing head is circularly shifted to the set maximum jet orifice shift number P, namely the printing head is circularly shifted along the Y-axis forward and reverse directions until the printing of the current layer image is finished, and then the next layer is printed. And when the next layer is printed, the printing head is staggered by n jet holes (n is more than or equal to 1) in the Y-axis direction for printing.

Further, as shown in fig. 8, the image 70 needs to be printed on the current layer, the processed inkjet control image 71 and the stepping movement path 72 of the print head along the Y direction during the current layer printing are required to be opposite to each other, in order to ensure that the printed product after dislocation is consistent with the product before dislocation, i.e. the YZ plane of the image 70 needs to be printed on the current layer is a straight line. The stepping movement path 72 is a curve, the maximum dislocation distance in the Y direction is 25.4/R × P, and the scanning distance in the X direction per interval P changes in the Y stepping direction. Wherein, assuming that the X-direction scanning speed is V, the Y-direction stepping speed is 0.0847 × V.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A3D printing method is characterized in that in a set printing area, printing of each layer of a product to be printed is carried out in an XY plane;

before printing is started, rotating the printing head and/or the three-dimensional model to enable the printing head and/or the three-dimensional model to form an included angle alpha (0 degrees & lt alpha & lt 90 degrees) with the X axis; wherein the X-axis direction is the scanning direction of the print head;

2. 3D printing method according to claim 1, characterized in that said angle α < 45 °.

3. A 3D printing method according to claim 1, characterized in that:

as each layer is printed, the print head is also slowly stepped along the Y-axis while scanning in the X-axis direction.

4. A 3D printing method according to claim 3, wherein the print head is stepped forward along the Y axis by a distance of 1 orifice per 1mm of scan in the X axis direction.

5. A method of 3D printing according to claim 3, wherein the print head is cycled forward and backward along the Y axis while scanning in the X axis scan direction.

6. The 3D printing method according to claim 5, wherein the print head scans along the X-axis while stepping along the Y-axis one nozzle at a time until the print head steps along the Y-axis to the maximum set number of nozzles P, and then stepping along the Y-axis one nozzle at a time until the print head steps along the Y-axis to the maximum set number of nozzles P, and so on until the current layer is printed.

7. A printer comprising a memory, a processor and a computer program stored in said memory and executable on said processor, wherein said processor executes said computer program to implement the steps of the method according to any one of claims 1 to 6 in real time.

8. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to.

9. A printed product obtained by using the printing method of any one of claims 1 to 6 or the printer of claim 7 or the readable storage medium of claim 8.