CN114536756A

CN114536756A - 3D printer, printing platform and leveling method thereof

Info

Publication number: CN114536756A
Application number: CN202210234455.4A
Authority: CN
Inventors: 陈学栋; 吴桐; 谭冰峰; 谢洪言
Original assignee: Shenzhen Snapmaker Technologies Co ltd
Current assignee: Shenzhen Snapmaker Technologies Co ltd
Priority date: 2022-03-10
Filing date: 2022-03-10
Publication date: 2022-05-27

Abstract

The invention discloses a 3D printer, a printing platform and a leveling method thereof, wherein the method comprises the following steps: the tip of the nozzle of the printing nozzle is contacted with the first contact point to obtain a first z coordinate value₁The first contact point is used as a reference point; the tip of the nozzle of the printing nozzle is in contact with the second contact point to obtain a second z-coordinate value₂Thereby obtaining a second contact point relative to the first contact pointHeight difference Δ h of contact point₁＝z₂‑z₁(ii) a The tip of the nozzle of the printing nozzle is contacted with a third contact point to obtain a third z-coordinate value₃Thereby obtaining the height difference deltah of the third contact point relative to the first contact point₂＝z₃‑z₁(ii) a By analogy, the tip of the nozzle of the printing nozzle is contacted with the nth contact point to obtain the nth z coordinate value_nThereby obtaining the height difference deltah of the n-th contact point relative to the first contact point_n＝z_n‑z₁(ii) a Wherein, according to Δ h₁、Δh₂…Δh_nThe height of the printing platform is adjusted.

Description

3D printer, printing platform and leveling method thereof

Technical Field

The invention relates to the field of 3D printing, in particular to a 3D printer, a printing platform thereof and a method for leveling the printing platform.

Background

In the 3D printer, whether a printing platform can provide an approximately horizontal x-y plane or not has great influence on printing precision; users have strong demands for high printing efficiency and intelligent usability. The plane of the printing platform is adjusted manually mostly by the existing 3D printer, which is troublesome and laborious, and the precision is lower due to inevitable human errors in manual calibration.

The mainstream FDM type in the existing market is mainly a single-head 3D printer, only one material can be printed at one time, the material can not be combined and matched for use, meanwhile, the forming efficiency is not high due to the limitation of the printing speed. The user has strong demands on high printing efficiency, high quality, multi-material compatibility, mixed usability, intelligent usability and moderate price.

However, manual calibration is mostly adopted in the existing dual-nozzle 3D printer, which is troublesome and labor-consuming, and due to unavoidable human errors, the calibrated nozzle often has large errors, and the calibration precision is low. Moreover, during the calibration process, the detection is performed by means of other calibration devices, resulting in an excessively complex machine structure.

There is a need in the art to develop an improved, faster, more accurate, and more reliable print platform leveling technique that alleviates or overcomes the above-mentioned technical deficiencies, as well as achieves other beneficial technical effects.

The information included in this background section of the present specification, including any references cited herein and any descriptions or discussions thereof, is included for technical reference purposes only and is not to be taken as subject matter which would limit the scope of the present invention.

Disclosure of Invention

The present invention has been made in view of the above and other more conception.

According to a basic idea of an aspect of the invention, improved, faster, more accurate, more reliable print deck leveling techniques and dual head calibration methods can be provided by directly using the head tips for calibration without additional calibration equipment.

According to one of the concepts of the present invention, a method for calibrating dual nozzles of a 3D printer is presented. The calibration method has the advantages of rapidness, automation, intellectualization, high precision and the like because the algorithm and the steps adopted by the standard method are more simplified. For a 3D printer with double nozzles, the intelligent calibration precision can be within 0.01mm, manual intervention is not needed, the whole calibration process is completely carried out by a machine, and the calibration speed is high, and can be completed within 2-3 s.

According to another aspect of the invention, there is provided a method for calibrating a dual-jet 3D printer, the 3D printer comprising first and second print jets; a print platform on which a calibration target with a conductive edge can be disposed, the calibration target configured to form an electrical continuity signal when the print head is in contact with the conductive edge of the calibration target; and a controller configured to acquire the turn-on signal and thereby obtain coordinate parameters of a contact position of the print head with a conductive edge of the calibration target, the method comprising the steps of: contacting the first print head with the conductive edge of the calibration target to obtain a first center coordinate of the calibration target based on the first print head; contacting the second print head with a conductive edge of the calibration target to obtain a second center coordinate of the calibration target based on the second print head;

calculating a coordinate deviation (Δ X, Δ Y) of the second print jet relative to the first print jet based on a difference between the first center coordinate and the second center coordinate; and compensating the X and Y coordinate values of the second print head according to the coordinate deviation (Δ X, Δ Y).

According to an embodiment, the first and second print heads are each in electrically conductive contact with the conductive edge of the calibration target through their respective head tips.

According to an embodiment, the conductive edges of the calibration target form a circle, the center of the calibration target being the center of the circle; wherein a first center coordinate (X) of the calibration target is obtained by the first print head contacting at least three point contact positions on the circumference of the circle₁,Y₁) (ii) a And obtaining a second center coordinate (X) of the calibration target by contacting the second printing head with at least three contact positions on the circumference of the circle₂,Y₂)。

According to one embodiment, the coordinate values (x) of the three-point contact positions are obtained by the first and second printing heads contacting the three-point contact positions on the circumference of the circle respectively₁,y₁)、(x₂,y₂) And (x)₃,y₃) First and second central coordinate values (X, Y) of the calibration target are calculated by the following equations, respectively: x ═ g-cf)/(eb-af), Y ═ g-ce)/(af-be), where,

a＝2x₃-2x₂；b＝2y₃-2y₂；c＝x₃2-x₂2+y₃2-y₂2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

according to an embodiment, the three point contact positions trisect the circumference of the circle.

According to one embodiment, the first and second print heads are in contact with four-point contact positions on the circumference of the circle respectivelyCoordinate value (x) of four-point contact position₁,y₁)、(x₂,y₂)、(x₃,y₃) And (x)₄,y₄) First and second central coordinate values (X, Y) of the calibration target are calculated by the following equations, respectively: x ═ gb-cf)/(eb-af), Y ═ ag-ce)/(af-be,

wherein a is 2x₄-2x₃；b＝2y₄-2y₃；c＝x₄2-x₃2+y₄2-y₃2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

According to one embodiment, the four-point contact location bisects the circumference of the circle.

According to one embodiment, the conductive edges of the calibration target form a square; wherein a first center coordinate (X) of the calibration target is obtained by the first print head contacting four contact positions respectively located on four sides of the square₁,Y₁) (ii) a And obtaining a second center coordinate (X) of the calibration target by contacting the second printing head with four contact positions respectively located on four sides of the square₂,Y₂)。

According to one embodiment, two x-coordinate values, x, are obtained by the contact of the first and second print heads with the left and right sides of the square respectively_{Left side of}And x_{Right side}(ii) a Two y coordinate values are obtained by the contact of the first printing nozzle and the second printing nozzle with the upper side and the lower side of the square respectively, and y is_{On the upper part}And y_{Lower part}(ii) a And calculating first and second central coordinate values (X, Y) of the calibration target by the following equations:

X＝(x_{left side of}+x_{Right side})/2，Y＝(y_{On the upper part}+y_{Lower part})/2。

According to an embodiment, the calibration target is a hole or a land provided on the printing platform, wherein the edge of the hole or land constitutes the conductive edge.

According to an embodiment, the calibration target is a hole formed in the center of the printing platform, the hole being a through hole or a blind hole.

According to an embodiment, the calibration target is a boss fixed to or integrally formed in the center of the printing platform, the boss constituting its edge a conductive edge by being made of metal or by applying a conductive coating.

According to an embodiment, the calibration target has an upper surface configured to form a conducting signal when a tip of the print head is in contact with the upper surface of the calibration target, the method further comprising the steps of:

the tip of the first print head is brought into contact with the upper surface of the calibration target to obtain a z-coordinate value corresponding to the first print head₁'; the tip of the second printing nozzle is contacted with the upper surface of the calibration target contacted with the first printing nozzle, and the z-coordinate value corresponding to the second printing nozzle is obtained₂' from which the difference in height Δ m-z of the first print head relative to the second print head is obtained₁’-z₂'; and adjusting the height of the second printing nozzle according to the delta m.

According to another aspect of the present invention, there is disclosed an auto-calibratable dual head 3D printer, the dual head 3D printer comprising: first and second print heads; a print platform disposed below the first and second print heads and on which a calibration target with a conductive edge may be disposed, the calibration target configured to form an electrical continuity signal when the print heads are in contact with the conductive edge of the calibration target; a controller configured to acquire the turn-on signal and thereby obtain coordinate parameters of a contact position of the print head with a conductive edge of the calibration target; and a linear module configured to linearly move the print head and the print platform relative to each other in three directions of x, y, and z axes, wherein the dual head 3D printer is configured to automatically perform the steps of: driving the first printing nozzle to be in contact with the conductive edge of the calibration target, and obtaining a first center coordinate of the calibration target based on the first printing nozzle; driving the second printing nozzle to contact with the conductive edge of the calibration target to obtain a second center coordinate of the calibration target based on the second printing nozzle; calculating a coordinate deviation (Δ X, Δ Y) of the second print jet relative to the first print jet based on a difference between the first center coordinate and the second center coordinate; and compensating for the X and Y coordinate values of the second print head in dependence on the coordinate deviation (Δ X, Δ Y).

According to an embodiment, the first and second print heads are configured to be brought into electrically conductive contact with the conductive edge of the calibration target by their respective head tips, respectively.

According to an embodiment, the dual-nozzle 3D printer is configured to obtain coordinate values (x) of three-point contact positions on the circumference of the circle by contacting the first and second printing nozzles with the three-point contact positions, respectively₁,y₁)、(x₂,y₂) And (x)₃,y₃) First and second central coordinate values (X, Y) of the calibration target are calculated by the following equations, respectively: x ═ b-cf)/(eb-af),

y ═ ag-ce)/(af-be), where,

a＝2x₃-2x₂；b＝2y₃-2y₂；c＝x₃2-x₂2+y₃2-y₂2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

According to an embodiment, the pairThe nozzle 3D printer is configured to obtain coordinate values (x) of four-point contact positions on the circumference of the circle by respectively contacting the first and second printing nozzles with the four-point contact positions₁,y₁)、(x₂,y₂)、(x₃,y₃) And (x)₄,y₄) First and second central coordinate values (X, Y) of the calibration target are calculated by the following equations, respectively: x ═ g-cf)/(eb-af), Y ═ g-ce)/(af-be), where,

a＝2x₄-2x₃；b＝2y₄-2y₃；c＝x₄2-x₃2+y₄2-y₃2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

According to one embodiment, the conductive edges of the calibration target form a square; wherein the dual head 3D printer is configured to obtain a first center coordinate (X) of the calibration target by the first print head contacting four contact positions respectively located on four sides of the square₁,Y₁) (ii) a And the dual head 3D printer is configured to obtain a second center coordinate (X) of the calibration target by the second printing head contacting four contact positions respectively located on four sides of the square₂,Y₂)。

According to an embodiment, the dual head 3D printer is configured to: obtaining two x coordinate values x through the contact of the first printing nozzle and the second printing nozzle with the left side and the right side of the square respectively_{Left side of}And x_{Right side}(ii) a Two y coordinate values are obtained by the contact of the first printing nozzle and the second printing nozzle with the upper side and the lower side of the square respectively, and y is_{On the upper part}And y_{Lower part}(ii) a Calculating first and second central coordinate values (X, Y) of the calibration target by the following equations:

According to an embodiment, the calibration target may have an upper surface configured to form a turn-on signal when a tip of the print head is in contact with the upper surface of the calibration target, the method further comprising the steps of:

According to another aspect of the invention, a printing platform for a 3D printer is further provided, wherein n conductive contact points which are spaced from each other and are not in the same straight line are arranged on the printing platform, n is an integer which is not less than 3, and the contact points are used for leveling the printing platform; and, the 3D printer is configured to output a conduction signal when its printing nozzle is in contact with the contact point and forms a conduction circuit.

According to an embodiment, the printing platform is provided with a plurality of adjustment feet.

According to one embodiment, the adjusting foot is provided with an adjusting scale.

According to an embodiment, a calibration target is further provided on the printing platform.

According to an embodiment, the calibration target is a through hole or a blind hole formed on the printing platform, or a boss provided on the printing platform.

According to another aspect of the invention, a 3D printer is also provided, which is provided with the printing platform.

According to an embodiment, the 3D printer is a dual-jet 3D printer having two printing jets.

According to one embodiment, the printing platform is provided with n conductive contact points, wherein n is an integer greater than or equal to 3, the n contact points are spaced from each other and are not in the same straight line, and the contact points are used for leveling the printing platform; wherein the method further comprises the step of leveling the printing platform: s1: contacting the tip of at least one of the print heads with the first contact point to obtain a first z-coordinate value₁The first contact point is used as a reference point; s2: contacting the tip of the print head with the second contact point to obtain a second z-coordinate value z₂Thereby obtaining a height difference Deltah of the second contact point relative to the first contact point₁＝z₂-z₁(ii) a S3: contacting the tip of the print head with the third contact point to obtain a third z-coordinate value z₃Thereby obtaining a height difference Δ h of the third contact point with respect to the first contact point₂＝z₃-z₁(ii) a S4: and analogizing, enabling the nozzle tip of the printing nozzle to be in contact with the nth contact point to obtain the nth z coordinate value_nThereby obtaining a height difference Deltah of the n-th contact point relative to the first contact point_n＝z_n-z₁(ii) a Wherein, according to Δ h₁、Δh₂…Δh_nAdjusting the height of the printing platform.

According to an embodiment, the step S1 includes: providing first, second and third contact points on the printing platform, wherein the first contact point serves as a reference point and the three contact points are set to one of: the first, second and third contact points are three vertices of an isosceles triangle or equilateral triangle; said first, second and third contact points lie on and trisect the circumference of a circle; and said first contact point is located at the centre of a circle, said second and third contact points being located on the circumference of the circle and being arranged mirror-symmetrically with respect to the diameter of the circle.

According to an embodiment, the second and third contact points are located at two vertices of the base of the isosceles triangle, respectively, and the first contact point is located at the other vertex of the isosceles triangle.

According to an embodiment, the step S1 includes: providing four contact points spaced apart from one another on the printing platform, the four contact points being set to one of: the four contact points are four vertices of a square; the four contact points belong to four vertexes of a polygon; one of the four contact points is positioned at the center of a circle, and the other three contact points are positioned on the circumference of the circle and trisect the circumference; and the four contact points lie on the circumference of a circle and bisect the circumference.

According to one embodiment, the calibration method enables the intelligent calibration accuracy of the x-y plane of the 3D printer to be within 0.01 mm.

According to one embodiment, the calibration method described above allows calibration to be performed within 2-3 s.

According to an aspect of the invention, there is provided a method for leveling of a printing platform of a 3D printer, the 3D printer comprising: at least one print head; the printing platform is provided with n conductive contact points, wherein n is an integer larger than or equal to 3, the n contact points are spaced from each other and are not in the same straight line, and the n contact points are configured to form a conducting signal when the tip of the printing spray head is in contact with the contact points; a controller configured to obtain the turn-on signal and a z-axis height of the print head when the print head contacts the print platform, wherein the method comprises: s1: contacting the tip of the print head with the first contact point to obtain a first z-coordinate value z₁The first contact point is used as a reference point; s2: make the printing jetThe tip of the nozzle is in contact with the second contact point to obtain a second z-coordinate value₂Thereby obtaining a height difference Deltah of the second contact point relative to the first contact point₁＝z₂-z₁(ii) a S3: contacting the tip of the print head with the third contact point to obtain a third z-coordinate value z₃Thereby obtaining a height difference Δ h of the third contact point with respect to the first contact point₂＝z₃-z₁(ii) a S4: and analogizing, enabling the nozzle tip of the printing nozzle to be in contact with the nth contact point to obtain the nth z coordinate value_nThereby obtaining a height difference Deltah of the n-th contact point relative to the first contact point_n＝z_n-z₁(ii) a S5: according to Δ h₁、Δh₂…Δh_nAdjusting the height of the printing platform.

According to an embodiment, the contact points are formed by a metallic body embedded in the printing platform or by a metallic plating or conductive coating applied on the printing platform and having a surface substantially on the same face as the printing platform.

According to one embodiment, the adjusting foot has an adjusting scale thereon.

According to an embodiment, the 3D printer is a dual-jet printer having two printing jets.

According to an embodiment, the step S1 includes: providing at least first, second and third contact points on the printing platform, wherein the first contact point serves as a reference point and the three contact points are set to one of: the first, second and third contact points are three vertices of an isosceles triangle or equilateral triangle; said first, second and third contact points lie on and trisect the circumference of a circle; and said first contact point is located at the centre of a circle, said second and third contact points being located on the circumference of the circle and being arranged mirror-symmetrically with respect to the diameter of the circle.

According to an embodiment, wherein the method is performed automatically by the 3D printer.

According to an embodiment, the steps S2-S5 are performed by one print head of the dual head printer; alternatively, the steps S2-S5 are performed by each print head of the dual head printer, respectively.

According to an embodiment, the 3D printer comprises a sensor, and the 3D printer is configured to form a conducting circuit to send out a conducting signal when the printing nozzle and the contact point are printed, the sensor detects the conducting signal, wherein the first z-coordinate value is obtained by obtaining a z-coordinate value of a conducting position indicated by the conducting signal₁The second z-coordinate value z₂And a third z-coordinate value z₃。

According to one embodiment, the 3D printer is provided with an x-axis linear module, a y-axis linear module and a z-axis linear module which respectively drive the printing nozzle to do linear motion in the directions of an x axis, a y axis and a z axis.

According to another aspect of the invention, a printing platform for a 3D printer is further provided, wherein n conductive contact points which are spaced from each other and are not in the same straight line are arranged on the printing platform, n is an integer which is not less than 3, and the contact points are used for leveling the printing platform; and the 3D printer is configured to output a conducting signal when the printing nozzle is in contact with the contact point and forms a conducting circuit.

According to an embodiment, the printing platform has a printing base plate and a printing top plate, wherein the printing top plate is detachably fixed on the printing base plate.

According to an embodiment, the printing platform is provided with n adjusting feet corresponding to the n contact points, and the height of the printing platform is adjusted by adjusting at least one of the adjusting feet of the printing platform.

According to one embodiment, the adjusting foot has an adjusting scale thereon.

According to another aspect of the present invention, there is also provided a printing platform for a 3D printer, the printing platform comprising: printing a bottom plate; and a printing top plate mounted on the printing bottom plate in an overlapping manner; wherein, at least three conductive contact points which are separated from each other and are not on the same straight line are arranged on the printing top plate; and wherein a calibration target is provided on the printing head plate.

According to an embodiment, the printing top plate is detachably mounted above the printing bottom plate.

According to an embodiment, the printing top plate is fixed to the printing bottom plate by magnetic attraction, vacuum attraction, or mechanical fasteners.

According to an embodiment, the printing platform is provided with at least one adjustment foot.

According to an embodiment, the calibration target is a through hole or a blind hole with a conductive edge formed on the printing top plate, or a boss with a conductive edge disposed on the printing top plate.

According to an embodiment, the printing head plate is provided with a heating mechanism.

According to an embodiment, the heating mechanism is a resistance wire or an electrically heatable PCB board.

According to an embodiment, the contact point is formed by a metal body embedded in the printing top plate or a metal plating or conductive coating coated on the printing top plate.

According to an embodiment, a non-conductive film, coating or adhesive layer is provided on the top printing plate around the contact points.

According to an embodiment, the 3D printer is a dual-nozzle 3D printer having two printing nozzles.

The invention can directly adopt the spray head tip to participate in calibration, and can provide an improved, faster, higher-precision and more reliable printing platform leveling technology and a double-spray head calibration method without additional expensive accessories or equipment, thereby improving the efficiency, reducing the hardware cost and reducing the complexity of operation and equipment.

Further embodiments of the invention are also capable of achieving other advantageous technical effects not listed, which other technical effects may be partially described below and which would be expected and understood by one skilled in the art after reading the present invention.

Drawings

The above features and advantages and other features and advantages of these embodiments, and the manner of attaining them, will become more apparent and the embodiments of the invention will be better understood by reference to the following description taken in conjunction with the accompanying drawings.

Fig. 1 schematically shows a perspective view of a 3D printer having dual heads according to an embodiment of the present invention.

Fig. 2 schematically shows a front view of the 3D printer shown in fig. 1.

Fig. 3 shows a perspective view of the 3D printer platform with contact points and calibration targets of the dual-jet 3D printer of fig. 1.

Fig. 4 is a top view schematically illustrating the printing platform shown in fig. 3.

Fig. 5 is an enlarged view schematically showing a calibration target of the printing platform shown in fig. 3.

Detailed Description

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

It is to be understood that the embodiments illustrated and described are not limited in application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The illustrated embodiments are capable of other embodiments and of being practiced or of being carried out in various ways. Examples are provided by way of explanation of the disclosed embodiments, not limitation. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present invention without departing from the scope or spirit of the disclosure. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents.

Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

The term "3D printer" encompasses not only three-dimensional printing devices in the general sense of the art, such as industrial grade 3D printers, including consumer grade 3D printers, but also laser processing devices with 3D printing functionality, and 3D printing devices with laser processing functionality, all within the scope of the "3D printer" of the present application.

In the present application, the "3D printer" may include not only a function of constructing an object by stacking and stacking three-dimensional objects layer by means of spraying an adhesive agent or extrusion using an adhesive material such as powdered metal or plastic, but also a laser processing function selectively according to the application. For example, laser machining may include laser cutting, engraving, burning, ablation (laser ablation), and the like. The term "engraving" as described above refers to the process by which a 3D printer changes the appearance of a material without cutting through it. For example, for a laser cutting machine, it may mean removing some material from a surface, or discoloring a material by applying electromagnetic radiation, or the like.

As used herein, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may include, for example, a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms herein can be understood by those of ordinary skill in the art as appropriate.

The present invention will be described in more detail below with reference to specific examples thereof.

According to one of the basic solution concepts of the present invention, the coordinates of the geometric center point of the calibration target may be obtained by bringing two heads of the dual head 3D printer into contact with the edges of the calibration target, respectively. Therefore, any shape of calibration target, the geometric center coordinates of which can be found from a plurality of coordinate points on the edge thereof, can be applied to the present invention.

For example, as shown in fig. 1 and 2, the 3D printer has a printing platform 10. Printing deck 10 theoretically defines an x-y plane defined by an x-axis and a y-axis. Wherein the x, y and z axes are perpendicular to each other. The term "along an axis" motion, such as along an x-axis, y-axis, or z-axis, means parallel to the axis or in line with the axis. In this document, the designated orientation of the x-axis, y-axis or z-axis is merely for ease of discussion and does not constitute any limitation on orientation. Of course, those skilled in the art will also appreciate that the printing platform may be connected to the x-axis or y-axis linear module, which is not limited herein. In addition, the printing platform has a heating function, can be an integral plate, and also can be composed of a plurality of layers of plates in a detachable or non-detachable mode.

The dual head 3D printer may be provided with x-axis, y-axis and z-axis linear modules 30, a printing platform 10, two heads 20, and driving motors (not shown) corresponding to the x-axis, y-axis and z-axis linear modules. Wherein, for example, an x-axis and a y-axis linear module 30 (typically with or including a drive motor or actuator) can be operably connected to each of the two spray heads 20 to control the independent movement of the two spray heads 20 along the x-axis and the y-axis. A z-axis linear module 30 (typically with or including a drive motor or actuator) is coupled to printing platform 10 to control movement of printing platform 10 along the z-axis.

The printing platform 10 of the dual-nozzle 3D printer may be used to place materials to be printed, substrates, and the like. Printing deck 10 provides a work plane that is as flat as possible. The printing platform 10 defines the range of motion of the print head. Printing deck 10 may preferably be generally square, rectangular, etc. in regular shape.

As shown in fig. 3 and 4, the printing platform 10 may be provided with a calibration target 13 for calibrating the two heads 20, and a preferred example of the calibration target 13 is a square. The position of the calibration target 13 is preferably arranged in the center of the printing platform 10. However, alternatively, the position of the calibration target 13 may be at other positions on the printing platform 10. Alternatively, the calibration target 13 may be any calibration target shape such as a rectangle or a circle whose geometric center point coordinates can be obtained from a plurality of coordinate points on its side. The calibration target 13 may also be provided with an electrically conductive upper surface 17.

As shown in fig. 3, 4 and 5, when the calibration target 13 is square or rectangular, the calibration target 13 has a first edge 16, a second edge 16, a third edge 16 and a fourth edge 16. The calibration target 13 is a through hole in the plane of the printing platform 10, but alternatively the calibration target 13 may also be a boss or bump protruding above the surface of the printing platform 10 instead of a through hole. Preferably, the calibration target 13 is a through hole in the plane of the printing platform 10, the edge (rim or edge) of which is substantially flush with the surface of the printing platform, and this is designed primarily to maintain the height of the printing platform to be consistent for ease of machining, operation and maintenance. In addition, the calibration target 13 is preferably highly conductive, which may be made entirely of a conductive material or have only its surface coated with a conductive coating. During the calibration process, when the nozzle 20 contacts the edge (edge) 16 of the calibration target 13, a conduction path is formed, and the controller acquires the conduction signal and reads the coordinate point of the conduction position.

According to one example, printing deck 10 has n electrically conductive contacts 12 on its surface, and when the print head contacts 12 and forms a conductive circuit, a conductive signal is sent to a control system or controller, for example. In this example, the contact points 12 are embedded in the printing platform 10 and have a surface substantially planar with the printing platform 10, and are arranged to prevent the conductive contact points from being arranged to cause the printing platform surface to be bumpy. Of course, one of ordinary skill in the art will appreciate that the surface of contact point 12 may not be flush with the surface of printing deck 10. Further, according to an example, the surface of the printing platform 10 is covered with a non-conductive film material, e.g. a polymer film, such as PET, PC, PVC, PEI, etc., in addition to the arranged contact points 12, which film material is intended to protect the printing platform 10.

According to an example, the printing platform 10 may be provided with n adjustment feet 11 corresponding to the n contact points 12, and the height of the printing platform 10 is adjusted by adjusting at least one of the adjustment feet 11 of the printing platform 10. The adjustable feet 11 can be rotated to control the elevation and lowering of the platform at the feet. The minimum scale on the foot may be set to 0.1mm, 0.01mm, etc. For example, if the system obtains that the z-axis height difference of the second contact point relative to the first contact point is +0.1mm, and the minimum scale on the support leg is set to 0.1mm when the system leaves the factory, the user can rotate the knob counterclockwise by one grid; if the system acquires that the z-axis height difference of the second contact point corresponding to the first contact point is-0.1 mm, and the minimum scale on the support leg is set to 0.1mm when the system leaves the factory, the user can rotate the knob clockwise by one grid.

Further, the 3D printer may be configured with a display screen on which the system displays the leveling data after it has acquired the data and refers to the user's need to adjust the foot clockwise or counterclockwise by several frames for each adjustment. The user can uniformly adjust the adjusting support legs after the system acquires the leveling data of each contact point.

Alternatively, the 3D printer may be configured to, after obtaining the leveling data of a single adjusting leg, move the printing platform away from the nozzle for a distance and to be stationary, then the user adjusts the adjusting leg according to the leveling data, then the printing platform approaches the nozzle again until it is in contact with the nozzle, and the system obtains the leveling data of the single adjusting leg again until the height difference of the contact point with respect to the first contact point is zero.

The controller of the 3D printer may be a main control chip, or may be another unit having a control function. In the scheme, the spray head, the contact point and the calibration target are made of metal materials and are conductive, and the spray head, the contact point and the calibration target are in contact to generate a conducting signal, for example, the spray head, the contact point and the calibration target generate a high level when in contact and generate a low level when in disconnection, and the platform can be leveled without an additional sensor. For example, some auto-leveling schemes require the use of electrical sensors, micro-switches or distance sensors, etc., which, in contrast, increase the cost of the additional parts, but also increase the complexity of the machine structure, reducing its robustness and reliability.

Leveling of printing platforms

According to one embodiment of the present invention, the z-axis coordinates at the time of contact are respectively obtained by bringing one printing head into contact with three contact points on the printing platform, one of which may serve as a reference point.

As shown in fig. 1 to 4, the 3D printer has an x-axis, y-axis and z-axis linear module 30, a printing platform 10, two printing heads 20, and driving motors (not shown) corresponding to the x-axis, y-axis and z-axis. The x-axis motor and the y-axis motor are respectively connected with the two printing nozzles 20 of the double-nozzle printer, and can control the two printing nozzles 20 to independently move along the x axis and the y axis; the driving motor of the z-axis is connected with the printing platform 10, and controls the printing platform 10 to move along the z-axis direction.

According to an aspect of the invention, there is provided a method for leveling a printing platform of a 3D printer, the 3D printer comprising: at least one print head 20; a print deck 10 having at least 3, e.g., 3-6, electrically conductive contact points 12 arranged, the contact points 12 being spaced apart from and not collinear with each other and configured to form an on signal when a tip of a print head contacts a contact point, and a controller or control module operable to obtain a z-axis height of the print head when the print head contacts the print deck. The leveling method comprises the following steps:

s1: the tip of the print head 20 is brought into contact with the first contact point 12 to obtain a first z-coordinate value z₁The first contact point 12 serves as a reference point;

s2: the tip of the print head 20 is brought into contact with the second contact point 12 to obtain a second z-coordinate value z₂The height difference Δ h of the second contact point 12 relative to the first contact point 12 is thus obtained₁＝z₂-z₁；

S3: the tip of the print head 20 is brought into contact with the third contact point 12 to obtain a third z-coordinate value z₃Thereby obtaining a height difference Δ h of the third contact point 12 with respect to the first contact point 12₂＝z₃-z₁；

S4: by analogy, the tip of the print head 20 is contacted with the n-th contact point 12 to obtain the n-th z-coordinate value_nThereby obtaining a height difference Δ h of the n-th contact point with respect to the first contact point 12_n＝z_n-z₁(ii) a And

s5: according to Δ h₁、Δh₂…Δh_nThe height of the printing platform 10 is adjusted.

Printing platform 10 defines an x-y plane defined by mutually perpendicular x-and y-axes, and print head 20 is positioned above printing platform 10 in a z-axis direction perpendicular to the x-y plane and is configured to be movable in the x-, y-and z-axis directions, which form a cartesian coordinate system, as can be readily appreciated, for example, with reference to fig. 1-4.

As shown in fig. 3 and 4, printing platform 10 has a plurality of contact points 12 thereon, and contact points 12 may be plural and are not limited to the arrangements shown in fig. 3-4. During leveling, the print head 20 will form a conduction path when contacting the contact point 12, the sensor will detect the conduction signal, and the system of the printer can read and record the z-coordinate point of the conduction position.

The steps of the leveling method according to one example are further described below.

Positioning the print head 20 over the print platform 10 with the contact point 12;

the tip of the print head 20 is brought into contact with a first contact point 12 (serving as a reference point) to obtain a first z-coordinate value z₁；

The tip of the print head 20 is brought into contact with the second contact point 12 to obtain a second z-coordinate value z₂The difference in height Δ z of the second contact point 12 with respect to the first contact point 12 is obtained₁＝z₂-z₁；

The tip of the print head 20 is brought into contact with the third contact point 12 to obtain a third z-coordinate value z₃The difference in height Δ z of the third contact point 12 with respect to the first contact point 12 is obtained₂＝z₃-z₁；

According to Δ z₁And Δ z₂Adjusting the height of the printing platform 10;

wherein the first contact point 12, the second contact point 12 and the third contact point 12 are arranged as three vertices of a triangle.

According to an example, the printing platform 10 may be provided with n adjusting legs 11 corresponding to the first, second and nth contact points 12, as shown in fig. 1-4, wherein n is an integer greater than or equal to 3, and the height of the printing platform 10 is adjusted by adjusting at least one of the adjusting legs 11 of the printing platform 10. The adjusting foot 11 may have an adjusting scale thereon.

According to one example, the contact points 12 are embedded on the printing platform and the surface is on the same face as the printing platform.

According to one example, the 3D printer may be a dual-jet printer having two print jets.

According to an example, the step S1 may include: providing first, second and third contact points 12 on the printing platform 10, wherein the first contact point 12 is a reference point and the three contact points 12 are set to one of the following: the first, second and third contact points 12 are the three vertices of an isosceles or equilateral triangle; the first, second and third contact points 12 are located on the circumference of a circle and trisect the circumference; and the first contact point 12 is located at the centre of a circle, and the second and third contact points 12 are located on the circumference of the circle and are arranged mirror-symmetrically with respect to the diameter of the circle.

According to one example, the second and third contact points 12 may be located at two vertices of the base of the isosceles triangle, respectively, and the first contact point 12 is located at the other vertex of the isosceles triangle.

According to an example, step S1 may include: four contact points 12 spaced apart from one another are provided on the printing platform 10, the four contact points 12 being set to one of the following:

according to one example, four contact points 12 may be the four vertices of a square;

according to one example, four contact points 12 may belong to four of the vertices of a polygon;

according to one example, one of the four contact points 12 may be located at the center of a circle, the remaining three contact points being located on and trisecting the circumference of the circle; and

according to one example, four contact points 12 may be located on the circumference of a circle and bisect the circumference.

The leveling method can be automatically executed by the 3D printer.

According to one example, steps S2-S5 may be performed by one print head 20 of a dual head printer; alternatively, steps S2-S5 are performed by each print head 20 in a dual head printer, respectively.

According to aAs an example, the 3D printer may include a sensor (not shown), and the 3D printer may be configured to form a conduction circuit to emit a conduction signal when the head and the contact point are printed, the sensor detecting the conduction signal, wherein the first z-coordinate value is obtained by acquiring a z-coordinate value of a conduction position indicated by the conduction signal₁The second z-coordinate value z₂And a third z-coordinate value z₃And so on.

According to one example, the 3D printer may be provided with an x-axis linear module, a y-axis linear module, and a z-axis linear module 30 that drive the print head to move linearly in x-axis, y-axis, and z-axis directions, respectively.

As shown in fig. 1-4, one aspect of the present invention also discloses a printing platform 10 for a 3D printer, the printing platform 10 having a printing substrate 14; a printing top plate 15, wherein the printing top plate 15 is detachably fixed on the printing bottom plate 14, for example, by magnetic adsorption, vacuum adsorption or mechanical means, n conductive contact points 12 which are spaced from each other and are not in the same straight line are arranged on the printing top plate 15, and n is an integer greater than or equal to 3; the main body of the print top plate 15 is a heating layer, which may be a layer of pcb (printed circuit board) board. In the power-on state, a heating mechanism or a heating module may be provided in the printing top plate 15, for example, a heating wire (resistance wire) or the like may heat the printing top plate 15 to a certain temperature. The contact points 12 are distributed over a plurality of locations on the surface of the heating layer, and the other parts of the surface of the heating layer, i.e. the parts other than the contact points 12, are non-conductive film materials, such as polymer films, e.g. PET, PC, PVC, PEI, etc., which may be sprayed onto the surface of the heating layer or may be adhesive layers adhered to the surface of the heating layer. Wherein, the 3D printer is configured to output a conducting signal when the printing nozzle 20 thereof is contacted with the contact point 12 and forms a conducting circuit. Other sheet layers may be fixed on the printing top plate 15 during printing as long as they can provide better flatness. Of course, the printing top plate 15 may also be configured such that the printer ejects the printing material directly thereon.

According to one example, the printing platform 10 may be provided with a plurality of adjustment feet 11 corresponding to a plurality of contact points, the height of the printing platform being adjusted by adjusting at least one of the adjustment feet 11 of the printing platform.

According to one example, a calibration target 13 may be provided on the printing platform 10.

According to an example, the calibration target 13 may be a through hole or a blind hole formed on the printing platform 10, or a boss provided on the printing platform 10.

In another aspect of the present invention, a 3D printer, such as a dual-nozzle 3D printer having two printing nozzles, is disclosed, which has the printing platform 10 described above.

Double-nozzle calibration of 3D printer

a. Xy direction calibration for dual jets

Another aspect of the invention discloses a method for calibrating a dual-jet 3D printer, the 3D printer comprising first and second print jets 20; a print platform 10 on which a calibration target 13 with a conductive edge may be disposed, the calibration target 13 being configured to form an electrical conduction signal when the print head 20 is in contact with the conductive edge 16 of the calibration target 13; and a controller configured to acquire the on-signal and thereby obtain coordinate parameters of the contact position of the print head 20 with the conductive edge 16 of the calibration target 13, the method comprising the steps of: bringing the first print head 20 into contact with the conductive edge 16 of the calibration target 13, obtaining a first center coordinate of the calibration target 13 based on the first print head 20; bringing the second print head 20 into contact with the conductive edge 16 of the calibration target 13, obtaining a second center coordinate of the calibration target 13 based on the second print head 20; calculating the coordinate deviation (Δ X, Δ Y) of the second printing nozzle 20 relative to the first printing nozzle 20 based on the difference between the first central coordinate and the second central coordinate; compensating the X and Y coordinate values of the second printing head according to the coordinate deviations (Δ X, Δ Y).

According to one example, the first and second print heads 20 may each be brought into electrically conductive contact with the conductive edge 16 of the calibration target 13 by their respective head tips.

According to one example, the conductive edge 16 of the calibration target 13 may constitute a circle, the center of the calibration target 13 being the center of the circle; wherein the first print head 20 is brought into contact with at least three points on the circumference of a circleContact to obtain a first center coordinate (X) of the calibration target 13₁,Y₁) (ii) a And, a second center coordinate (X) of the calibration target 13 is obtained by the second print head contacting at least three contact positions on the circumference of the circle₂,Y₂)。

According to one example, coordinate values (x) of three-point contact positions may be obtained by the first and second printing heads 20 contacting the three-point contact positions on the circumference of a circle, respectively₁,y₁)、(x₂,y₂) And (x)₃,y₃) First and second central coordinate values (X, Y) of the calibration target 13 are calculated by the following equations, respectively: x ═ g-cf)/(eb-af), Y ═ g-ce)/(af-be), where,

a＝2x₃-2x₂；b＝2y₃-2y₂；c＝x₃2-x₂2+y₃2-y₂2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

according to one example, the three point contact locations may trisect the circumference of a circle.

According to one example, coordinate values (x) of four-point contact positions may be obtained by contacting the first and second printing heads with the four-point contact positions on the circumference of a circle, respectively₁,y₁)、(x₂,y₂)、(x₃,y₃) And (x)₄,y₄) First and second center coordinate values (X, Y) of the calibration target 13 are calculated by the following equations, respectively: x ═ g-cf)/(eb-af), Y ═ g-ce)/(af-be), where,

a＝2x₄-2x₃；b＝2y₄-2y₃；c＝x₄2-x₃2+y₄2-y₃2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

according to one example, the four-point contact location may bisect the circumference of a circle.

According to one example, the conductive edges of the calibration target 13 may constitute a rectangle;

wherein the first center coordinate (X) of the calibration target 13 can be obtained by the first print head contacting four contact positions respectively located on four sides of the rectangle₁,Y₁) (ii) a Then, the second center coordinate (X) of the calibration target 13 is obtained by the second print head contacting four contact positions respectively located on four sides of the rectangle₂,Y₂)。

According to one example, two x-coordinate values, x, can be obtained by the contact of the first and second print heads with the left and right sides of the rectangle respectively_{Left side of}And x_{Right side}(ii) a Two y coordinate values are obtained by the contact of the first printing nozzle and the second printing nozzle with the upper side and the lower side of the rectangle respectively, and y is_{On the upper part}And y_{Lower part}(ii) a The first and second central coordinate values (X, Y) of the calibration target 13 are calculated by the following equations, respectively: x ═ X_{Left side of}+x_{Right side})/2，Y＝(y_{Upper part of}+y_{Lower part})/2。

According to one example, the calibration target 13 may be a hole or a boss provided on the printing platform, wherein the edge of the hole or the boss constitutes the conductive edge; alternatively, the calibration target 13 may be a hole formed in the center of the printing platform, which may be a through hole or a blind hole.

According to one example, the calibration target 13 may be a boss fixed to or integrally formed in the center of the printing platform, the boss constituting its edge a conductive edge by being made of metal or by applying a conductive coating.

Another aspect of the present invention discloses a dual-nozzle 3D printer capable of automatic calibration, the dual-nozzle 3D printer comprising: first and second print heads; a printing platform disposed below the first and second print heads, on which a calibration target 13 with a conductive edge may be disposed, the calibration target 13 being configured to form an electrical conduction signal when the print heads are in contact with the conductive edge of the calibration target 13; a controller configured to acquire a conduction signal and thereby obtain coordinate parameters of a contact position of the print head with a conductive edge of the calibration target 13; and a linear module configured to linearly move the printing nozzle and the printing platform relative to each other in three directions of x, y and z axes, wherein the dual-nozzle 3D printer is configured to automatically execute the following steps: driving the first printing nozzle to contact with the conductive edge of the calibration target 13 to obtain a first center coordinate of the calibration target 13 based on the first printing nozzle; driving the second printing nozzle to contact with the conductive edge of the calibration target 13 to obtain a second center coordinate of the calibration target 13 based on the second printing nozzle; calculating the coordinate deviation (delta X, delta Y) of the second printing nozzle relative to the first printing nozzle based on the difference value of the first central coordinate and the second central coordinate; compensating the X and Y coordinate values of the second printing head according to the coordinate deviation (Δ X, Δ Y).

According to one example, the first and second print heads may be configured to make electrically conductive contact with the conductive edge of the calibration target 13 through their respective head tips, respectively.

According to one example, the conductive edges of the calibration target 13 constitute a circle, the center of the calibration target 13 being the center of the circle; wherein a first center coordinate (X) of the calibration target 13 is obtained by the first print head contacting at least three contact points on the circumference of a circle₁,Y₁) (ii) a And, a second center coordinate (X) of the calibration target 13 is obtained by the second print head contacting at least three contact positions on the circumference of the circle₂,Y₂)。

According to one example, the dual head 3D printer may be configured to obtain coordinate values (x) of three-point contact positions by the first and second printing heads contacting the three-point contact positions on the circumference of the circle, respectively₁,y₁)、(x₂,y₂) And (x)₃,y₃) First and second central coordinate values (X, Y) of the calibration target 13 are calculated by the following equations, respectively: x ═ g-cf)/(eb-af), Y ═ g-ce)/(af-be), where a ═ 2X₃-2x₂；b＝2y₃-2y₂；c＝x₃2-x₂2+y₃2-y₂2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

According to one example, the three point contact location may trisect the circumference of a circle.

According to one example, the dual head 3D printer may be configured to obtain coordinate values (x) of four-point contact positions by the first and second printing heads contacting the four-point contact positions on the circumference of the circle, respectively₁,y₁)、(x₂,y₂)、(x₃,y₃) And (x)₄,y₄) First and second center coordinate values (X, Y) of the calibration target 13 are calculated by the following equations, respectively: x ═ g-cf)/(eb-af), Y ═ g-ce)/(af-be), where a ═ 2X₄-2x₃；b＝2y₄-2y₃；c＝x₄2-x₃2+y₄2-y₃2

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂2-x₁2+y₂2-y₁2。

According to one example, the conductive edges of the calibration target 13 may constitute a rectangle; wherein the dual-nozzle 3D printer is configured to obtain a first center coordinate (X) of the calibration target 13 by contacting a first printing nozzle with four contact positions respectively located on four sides of a rectangle₁,Y₁) (ii) a And, the dual head 3D printer is configured to obtain a second center coordinate (X) of the calibration target 13 by the second printing head contacting four contact positions respectively located on four sides of the rectangle₂,Y₂)。

According to one example, a dual-jet 3D printer may be configured to: two x coordinate values are obtained by the contact of the first printing nozzle and the second printing nozzle with the left side and the right side of the rectangle respectively, and x is_{Left side of}And x_{Right side}(ii) a Two y coordinate values are obtained by the contact of the first printing nozzle and the second printing nozzle with the upper side and the lower side of the rectangle respectively, and y is_{On the upper part}And y_{Lower part}(ii) a And first and second central coordinate values (X, Y) of the calibration target 13 are calculated by the following equations, respectively: x ═ X_{Left side of}+x_{Right side})/2，Y＝(y_{Upper part of}+y_{Lower part})/2。

The steps of the calibration method according to an embodiment of the invention are further described below with reference to the drawings.

For example, as shown in FIGS. 1-4, the dual head 20 of a dual head 3D printer is positioned over the calibration target 13, the calibration target 13 has an edge, and the head tip of the first head is brought into contact with the edge of the calibration target 13 to obtain the center coordinate (x) of the calibration target 13₁,y₁) The center coordinate (x) of the calibration target 13 is obtained by bringing the head tip of the second head into contact with the edge of the calibration target 13₂,y₂) The positional deviation (Δ x, Δ y) of the second head with respect to the first head is obtained as (x)₁-x₂,y₁-y₂₎And compensating the coordinates of the second spray head according to the (delta x, delta y).

The calibration target 13 may be a hole or a boss provided on the printing platform 10, the edge of which constitutes an electrically conductive edge. For example, the calibration target 13 in a land pattern provided on the printing platform 10 may be made of a conductive metal or coated with a conductive coating so that the edge thereof is conductive. For example, the calibration target 13 may be a hole formed in the center of the printing platform 10, the hole being a through hole or a blind hole, as shown in fig. 3-4.

Several alternative embodiments of the calibration step are described below.

Calibration using square or rectangular calibration targets

When the calibration target 13 has a square or rectangular shape, the two heads are in contact with the four edges of the calibration target 13, respectively, and when in contact, the heads are in conduction with the calibration target 13, and the coordinates of the positions of the heads are recorded. When in contact with the left edge, record x_{Left side of}(ii) a When in contact with the right edge, record x_{Right side}(ii) a While in contact with the upper edge, record y_{On the upper part}(ii) a When in contact with the lower edge, y is recorded_{Lower part}. Wherein x₁Or x₂＝(x_{Left side of}+x_{Right side})/2；y₁Or y₂＝(y_{On the upper part}+y_{Lower part})/2。

Calibration using circular calibration targets

When the calibration target 13 is circular, the two nozzles are in contact with the edges of the calibration target, respectively, as long as the coordinates of the center of the circle can be calculated. Two nozzles can be contacted with the edge of the circle for more than three times respectively, and three points are taken. The calculation is as follows: the center of the circle is (X, Y), R is the radius of the circle, and the coordinates of three points on the circle are respectively (X)₁,y₁)、(x₂,y₂)、(x₃,y₃)，

From the equation of the circle:

(x₁-X)²+(y₁-Y)²＝R²(1) formula (II)

(x₂-X)²+(y₂-Y)²＝R²(2) Formula (II)

(x₃-X)²+(y₃-Y)²＝R²(3) Formula (II)

(1) - (2), i.e. left minus left, right minus right, to obtain

x₁ ²-2Xx₁+X2+(y₁ ²-2Yy₁+Y2)-(x₂ ²-2Xx₂+X2)-(y₂ ²-2Yy₂+Y²)＝R²-R²

Finishing the formula to obtain:

x₁ ²-x₂ ²-2*x₁*X+2*x₂*X+y₁2-y₂2-2*y₁*Y+2*y₂*Y＝0

(2) - (3) finishing to obtain:

x₂2-x₃2-2*x₂*X+2*x₃*X+y₂2-y₃2-2*y₂*Y+2y₃*Y＝0

then the two formulas are arranged to obtain:

(2x₂-2x₁)X+(2y₂-2y₁)Y＝x₂ ²-x₁ ²+y₂ ²-y₁ ²

(2x₃-2x₂)X+(2y₃-2y₂)Y＝x₃ ²-x₂ ²+y₃ ²-y₂ ²

order:

a＝2x₃-2x₂；b＝2y₃-2y₂；c＝x₃ ²-x₂ ²+y₃ ²-y₂ ²

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂ ²-x₁ ²+y₂ ²-y₁ ²

thus, we obtain:

eX+fY＝g

aX+bY＝c

solving the above formula to obtain:

X＝(gb-cf)\(eb-af)

Y＝(ag-ce)\(af-be)。

the two nozzles can be respectively contacted with the circular edge for more than three times, and four points are taken. The calculation is as follows: the center of the circle is (X, Y), R is the radius of the circle, and the coordinates of three points on the circle are respectively (X)₁,y₁)、(x₂,y₂)、(x₃,y₃)、(x₄,y₄)，

From the equation of the circle:

(x₁-X)²+(y₁-Y)²＝R²(1) is of the formula

(x₂-X)²+(y₂-Y)²＝R²(2) Formula (II)

(x₃-X)²+(y₃-Y)²＝R²(3) Formula (II)

(x₄-X)²+(y₄-Y)²＝R²(4) Formula (II)

(1) - (2), that is, left minus left, right minus right, can be obtained

x₁ ²-2Xx₁+X²+(y₁ ²-2Yy₁+Y²)-(x₂ ²-2Xx₂+X²)-(y₂ ²-2Yy₂+Y²)＝R²-R²

Is finished to obtain

x₁ ²-x₂ ²-2*x₁*X+2*x₂*X+y₁ ²-y₂ ²-2*y₁*Y+2*y₂*Y＝0

(3) Finishing to obtain:

x₃ ²-x₄ ²-2*x₃*X+2*x₄*X+y₃ ²-y₄ ²-2*y₃*Y+2y₄*Y＝0

then the two formulas are arranged to obtain

(2x₂-2x₁)X+(2y₂-2y₁)Y＝x₂ ²-x₁ ²+y₂ ²-y₁ ²

(2x₄-2x₃)X+(2y₄-2y₃)Y＝x₄ ²-x₃ ²+y₄ ²-y₃ ²

Order:

a＝2x₄-2x₃；b＝2y₄-2y₃；c＝x₄ ²-x₃ ²+y₄ ²-y₃ ²

e＝2x₂-2x₁；f＝2y₂-2y₁；g＝x₂ ²-x₁ ²+y₂ ²-y₁ ²

then there are

eX+fY＝g

aX+bY＝c

Get it solved

X＝(gb-cf)\(eb-af)

Y＝(ag-ce)\(af-be)。

b. Z-direction calibration of dual jets

b1. Calibration target assisted z-direction calibration of dual jets

The calibration target has an upper surface configured to form a turn-on signal when a tip of the print head is in contact with the upper surface of the calibration target,

the method further comprises the following steps:

the tip of the first print head is brought into contact with the upper surface of the calibration target to obtain a z-coordinate value corresponding to the first print head₁’；

The tip of the second print head is brought into contact with the upper surface of the calibration target to obtain a z-coordinate value corresponding to the second print head₂' from which the difference in height Δ m-z of the first print head relative to the second print head is obtained₁’-z₂’；

And adjusting the height of the second printing nozzle according to the delta m.

b2. Contact point assisted z-direction calibration of dual jets

The printing platform is provided with n conductive contact points, n is an integer larger than or equal to 3, the n contact points are spaced from each other and are not in the same straight line, and are configured to form a conducting signal when the tip of the printing spray head is in contact with the contact points, and the controller acquires the conducting signal and the z-axis height of the printing spray head when the printing spray head is in contact with the contact points of the printing platform, and the method comprises the following steps:

the tip of the first print head is brought into contact with one of the contact points to obtain a z-coordinate value corresponding to the first print head₁’；

The tip of the second print head is contacted with the contact point of the tip of the first print head to obtain z-coordinate value corresponding to the second print head₂' from which the difference in height Δ m-z of the first print head relative to the second print head is obtained₁’-z₂’；

Any one, more or all of the above steps may be performed by a control system of the 3D printer, for example an automated control system. These steps may be performed by programming a control system processor.

The invention can simply, conveniently and low-cost carry out calibration and leveling, so that the defects of manual calibration, labor waste and inevitable human errors of the existing 3D printer, larger errors of the calibrated nozzle, lower calibration precision and the like can be reduced or even eliminated.

The foregoing description of several embodiments of the invention has been presented for the purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit the invention to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention and all equivalents be defined by the following claims.

Claims

1. A method for leveling of a printing platform of a 3D printer, the 3D printer comprising: at least one print head; the printing platform is provided with n conductive contact points, wherein n is an integer larger than or equal to 3, the n contact points are spaced from each other and are not in the same straight line, and the n contact points are configured to form a conducting signal when the tip of the printing spray head is in contact with the contact points; a controller for acquiring the conducting signal and the z-axis height of the printing nozzle when the printing nozzle is in contact with the printing platform,

wherein the method comprises the steps of:

s1: contacting the tip of the print head with the first contact point to obtain a first z-coordinate value z₁The first contact point is used as a reference point;

s2: contacting the tip of the print head with the second contact point to obtain a second z-coordinate value z₂Thereby obtaining a height difference Deltah of the second contact point relative to the first contact point₁＝z₂-z₁；

S3: contacting the tip of the print head with the third contact point to obtain a third z-coordinate value z₃Thereby obtaining a height difference Δ h of the third contact point with respect to the first contact point₂＝z₃-z₁(ii) a And

s4: and analogizing, enabling the nozzle tip of the printing nozzle to be in contact with the nth contact point to obtain the nth z coordinate value_nThereby obtaining the n-th contact point relative to the first contactHeight difference of dots Δ h_n＝z_n-z₁；

Wherein, according to Δ h₁、Δh₂…Δh_nAdjusting the height of the printing platform.

2. The method of claim 1, wherein the printing platform is provided with n adjustment feet corresponding to the first, second, third and nth contact points, and wherein the height of the printing platform is adjusted by adjusting at least one of the adjustment feet of the printing platform.

3. The method of claim 2, wherein the contact point is formed by a metal body embedded in the printing platform or a metallic plating or conductive coating applied on the printing platform and its surface is substantially on the same face as the printing platform.

4. The method of claim 2, wherein the adjustment foot has an adjustment scale thereon.

5. The method of claim 1, wherein the 3D printer is a dual-jet printer having two independent print jets.

6. The method according to claim 1, wherein the step S1 includes: providing first, second and third contact points on the printing platform, wherein the first contact point serves as a reference point and the three contact points are set to one of:

the first, second and third contact points are three vertices of an isosceles triangle or equilateral triangle;

said first, second and third contact points lie on and trisect a circular circumference; and

the first contact point is located at the center of a circle, and the second and third contact points are located on the circumference of the circle and are arranged mirror-symmetrically with respect to the diameter of the circle.

7. The method of claim 6, wherein the second and third contact points are located at two vertices of a base of the isosceles triangle, respectively, and the first contact point is located at the other vertex of the isosceles triangle.

8. The method according to claim 1, wherein the step S1 includes: providing four contact points spaced apart from one another on the printing platform, the four contact points being set to one of:

the four contact points are four vertices of a square;

the four contact points belong to four vertexes of a polygon;

one of the four contact points is positioned at the center of a circle, and the other three contact points are positioned on the circumference of the circle and trisect the circumference; and

the four contact points lie on a circular circumference and bisect the circumference.

9. The method of any of claims 1-8, wherein the method is performed automatically by the 3D printer.

10. The method of claim 4, wherein the steps S2-S5 are performed by one print head of the dual head printer; or

The steps S2-S5 are performed by each print head of the dual head printer, respectively.

11. The method according to any one of claims 1 to 10, wherein the 3D printer comprises a sensor and the 3D printer is configured to form a conducting circuit when the printing nozzle and the contact point to issue a conducting signal, the sensor detecting the conducting signal, wherein the first z-coordinate value z1, the second z-coordinate value z2 and the third z-coordinate value z3 are obtained by acquiring a z-coordinate value of a conducting position indicated by the conducting signal.

12. The method of any one of claims 1-11, wherein the 3D printer is provided with an x-axis linear module, a y-axis linear module, and a z-axis linear module that drive the print head to move linearly in x-axis, y-axis, and z-axis directions, respectively.

13. A printing platform for a 3D printer, the printing platform having a printing deck; a printing top plate detachably fixed on the printing bottom plate, wherein the printing top plate is provided with n conductive contact points which are spaced from each other and are not in the same straight line,

wherein n is an integer not less than 3; and is

The 3D printer is configured to output a conducting signal when the printing spray head of the 3D printer is in contact with the contact point and forms a conducting circuit.

14. The method of claim 13, wherein the printing platform is provided with n adjustment feet corresponding to the n contact points, and wherein the height of the printing platform is adjusted by adjusting at least one of the adjustment feet of the printing platform.

15. The printing platform of claim 13, wherein the printing platform is provided with a plurality of adjustment feet.

16. The printing platform of claim 15, wherein the adjustment foot has an adjustment scale thereon.

17. The printing platform of claim 13, wherein a calibration target is provided on the printing platform, the contact points being provided by conductive edges of the calibration target.

18. The printing platform of claim 17, wherein the calibration target is a through hole or a blind hole formed on the printing platform, or a boss provided on the printing platform.

19. A 3D printer having a printing platform according to any one of claims 13-18.

20. The printing platform of claim 19, wherein the 3D printer is a dual-jet 3D printer having two print jets.