阅读说明：本技术 一种高精度3d打印装置及其打印方法 (High-precision 3D printing device and printing method thereof ) 是由 朱伟军 曲优 李东升 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种高精度3D打印装置及其打印方法,该装置及方法突破了以往仅对工业机器人及3D打印算法层面改进以进行精度补偿在原理上的局限性,采用基于机器视觉及自动化控制的精度补偿机构,从而能够在实施3D打印的过程中对由3D打印工艺产生的打印误差及工业机器人自身的绝对定位误差进行高精度稳定补偿,实现对打印轨迹与姿态的精确控制,从而达到提高工业机器人3D打印产品打印精度,增加打印系统可靠性的目的。(The invention discloses a high-precision 3D printing device and a printing method thereof, which break through the limitation that in the past, only an industrial robot and a 3D printing algorithm are improved to carry out precision compensation on the principle, and a precision compensation mechanism based on machine vision and automatic control is adopted, so that the printing error generated by a 3D printing process and the absolute positioning error of the industrial robot can be stably compensated with high precision in the process of carrying out 3D printing, and the precise control on the printing track and the posture is realized, thereby achieving the purposes of improving the printing precision of 3D printing products of the industrial robot and increasing the reliability of a printing system.)

1. A high accuracy 3D printing device, characterized by includes: an industrial robot motion system, a compensation system, a vision system and a printing system; wherein the content of the first and second substances,

the industrial robot motion system is used as a base of the whole high-precision 3D printing device or is arranged on a guide rail and a rotary table and comprises an industrial robot and a central control unit;

the compensating system can accurately compensate errors in the process or the result generated by the robot motion and printing system in one or more degrees of freedom and comprises a compensating mechanism, a control unit and a driving unit, wherein the compensating system is connected to the tail end of the industrial robot and is provided with a vision system and the printing system;

the vision system is used for observing errors generated in the 3D printing process;

the printing system is used for implementing 3D printing work.

2. The high precision 3D printing device according to claim 1, wherein the compensation mechanism is a single axis or multi-axis series/parallel mechanism, the driving unit is operated by the control unit, and the compensation mechanisms are driven to move in respective degrees of freedom.

3. The high-precision 3D printing device according to claim 2, wherein the driving unit comprises a motor and other driving devices, and the control unit is a motion controller, a PLC or a single chip microcomputer.

4. The high-precision 3D printing device according to claim 1, wherein the vision system comprises a camera, a target or machine learning unit and an image processing unit, the camera is an industrial camera or a depth camera, the target or machine learning unit is used for helping the camera to recognize the pose information of the printing head, and the image processing unit is used for comparing the image shot by the camera with the target, obtaining a compensation amount, generating a compensation code and sending the compensation code to the compensation system.

5. The high precision 3D printing device according to claim 4, wherein the target is a print itself, a logo line on a printing platform or other information recognizable by a camera.

6. The high-precision 3D printing device according to claim 1, wherein the industrial robot is a multi-axis serial or parallel robot, and the central control unit is an independent control system or an industrial automation network.

7. The high precision 3D printing device according to claim 6, wherein the industrial robot is a six axis serial industrial robot.

8. The high precision 3D printing device according to claim 1, wherein the printing system comprises a print head, an extrusion unit, a heating unit, and a heat dissipation unit.

9. A 3D printing method based on the high-precision 3D printing device of any one of claims 1 to 8, comprising the steps of:

s1, according to the established three-dimensional model of the piece to be printed, the industrial robot moves the compensating system at the tail end of the industrial robot to a designated printing node;

s2, collecting the position and pose information of the printing head through a vision system, processing the data by an image processing unit to obtain compensation quantity and sending the compensation quantity to a compensation system;

s3, the compensation mechanism drives the printing system to move according to the compensation amount to complete compensation;

the S4 printing system implements a 3D print job;

s5 after the printing node finishes the printing work, the industrial robot moves the compensating system at the tail end of the industrial robot to the next printing node;

s6 repeats steps S2-S5 until the to-be-printed piece is printed and molded.

10. The 3D printing method according to claim 9, wherein the compensated print head pose information is collected using a vision system to evaluate the compensation accuracy after step S3 is completed.

Technical Field

The invention relates to the technical field of additive manufacturing, in particular to a high-precision 3D printing device and a printing method thereof.

Background

In recent years, with the rapid development of modern industry, the traditional processing mode can not meet the requirements of modern high and new technology for manufacturing products, and intelligence and automation are inevitable trends of future development of manufacturing industry. Meanwhile, the diversity of market demands also prompts the traditional manufacturing industry to change to green manufacturing, intelligent manufacturing and the like, and the production mode is gradually changed from a large-batch single mode to a small-batch personalized customization mode. In line with this demand, typical representatives of smart manufacturing, 3D printing technology is on the go and is rapidly developing.

Among the 3D printing technologies, the fused deposition manufacturing process is widely used in practical production due to its advantages of low equipment cost, simple process, high material utilization rate, and the like. The fused deposition manufacturing process 3D printer utilizes the fluidity and the caking property of thermoplastic materials in a molten state to heat the wires to be slightly higher than the melting temperature, the spray head performs X-Y plane motion based on horizontal layered data under the control of a computer, the wires are sent to the spray nozzle through the wire feeding device, heated, melted, extruded and adhered to the surface of the workbench, and then rapidly cooled and solidified. After each layer is printed, the height of the spray head is increased by one layer (or the height of the workbench is reduced by one layer), and the next layer is printed continuously. And repeating the steps, and finally realizing the molding and manufacturing of the whole three-dimensional model by completing the layer-by-layer printing through the movement of the spray head.

However, 3D printing is an additive manufacturing process that integrates multiple factors such as materials, processes, and equipment, and the curving and high precision of 3D printing are important research points in the industry. The industrial robot has the advantages of strong universality, stability, reliability, high repetition precision and the like, so that the industrial robot is applied to 3D printing and is used as a motion carrier in the printing process; meanwhile, a path improvement algorithm such as a space search method is also widely adopted for the problem of improving printing accuracy.

At present, the defects of the 3D printing process are mainly reflected in the following aspects: (1) the printing range of 3-axis printers based on fused deposition manufacturing processes is generally limited by the equipment frame, the printing space is often less than 0.5m3, and a larger range of components cannot be molded; (2) the 3-axis printer based on the fused deposition manufacturing process can only print a plane component due to the limitation of the degree of freedom of the mechanism, obvious steps can appear when a curved surface is printed, and the 3-axis printer has limitation on the printing of curved surface parts; (3) in a printing method based on a fused deposition process, errors may occur due to factors such as material properties, printing temperature, and a distance between a nozzle and a substrate during a printing process. Meanwhile, a system error is generated by the factors such as the load of the tail end of the robot, the rigidity of the mechanical arm, the moving speed and the like in the printing process by using the motion mechanism. The error generated by the superposition of the two is usually up to 2-3mm, and the printing precision is poor.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a high-precision 3D printing device and a printing method thereof, the device adopts a precision compensation mechanism based on machine vision and automatic control, so that the printing error generated by a 3D printing process and the absolute positioning error of an industrial robot can be stably compensated with high precision in the process of implementing 3D printing, the accurate control of the printing track and the posture is realized, and the aims of improving the printing precision of 3D printing products of the industrial robot and increasing the reliability of a printing system are fulfilled.

The technical scheme of the invention is as follows:

a high-precision 3D printing device, comprising: an industrial robot motion system, a compensation system, a vision system and a printing system; wherein the content of the first and second substances,

the industrial robot motion system is used as a base of the whole high-precision 3D printing device or is arranged on a guide rail and a rotary table and comprises an industrial robot and a central control unit;

the compensating system can accurately compensate errors in the process or the result generated by the robot motion and printing system in one or more degrees of freedom and comprises a compensating mechanism, a control unit and a driving unit, wherein the compensating system is connected to the tail end of the industrial robot, and a visual system and a printing system are installed on a printing support platform;

the vision system is used for observing errors generated by a printed product in the 3D printing process;

the printing system is used for implementing 3D printing work.

Preferably, the compensation mechanism is a single-shaft or multi-shaft series/parallel mechanism, the driving unit is controlled by the control unit, and the compensation mechanisms are driven to move in respective degrees of freedom.

Preferably, the compensation mechanism is a six-axis parallel platform, the driving unit comprises a motor and other driving devices, and the control unit is a motion controller, a PLC or a single chip microcomputer.

Preferably, the vision system includes a camera, a target or machine learning unit, and an image processing unit, the camera is an industrial camera or a depth camera, the target or machine learning unit is used for helping the camera to recognize pose information of the print head, and the image processing unit is used for comparing an image captured by the camera with the target, obtaining a compensation amount, generating a compensation code, and sending the compensation code to the compensation system.

Preferably, the target is the print itself, a logo line on the printing platform or other information recognizable by the camera.

Preferably, the industrial robot is a multi-axis serial or parallel robot, and the central control unit is an independent control system or an industrial automation network.

Preferably, the industrial robot is a six-axis tandem industrial robot.

Preferably, the printing system includes a print head, an extrusion unit, a heating unit, and a heat dissipation unit.

The invention also provides a printing method based on the high-precision 3D printing device, which comprises the following steps:

s1, according to the established three-dimensional model of the piece to be printed, the industrial robot moves the compensating system at the tail end of the industrial robot to a designated printing node;

s2, collecting the position and pose information of the printing head through a vision system, processing the data by an image processing unit to obtain compensation quantity and sending the compensation quantity to a compensation system;

s3, the compensation mechanism drives the printing system to move according to the compensation amount to complete compensation;

the S4 printing system implements a 3D print job;

s5 after the printing node finishes the printing work, the industrial robot moves the compensating system at the tail end of the industrial robot to the next printing node;

s6 repeats steps S2-S5 until the to-be-printed piece is printed and molded.

Preferably, after step S3 is completed, the compensated print head pose information is collected using a vision system to evaluate the compensation accuracy.

Compared with the prior art, the invention has the following advantages:

1. the high-precision 3D printing device breaks through the limitation of the prior art that only the industrial robot and a 3D printing algorithm are improved to carry out precision compensation on the principle, the compensation system is adopted to read image information and compensation data obtained by the vision system, the 3D printing process is compensated in real time, the 3D printing error comprehensively generated by the 3D printing process and the industrial robot can be effectively improved, and the 3D printing precision of the industrial robot is greatly improved.

2. The compensation system adopts a single-shaft or multi-shaft series/parallel mechanism, has the advantages of light weight and miniaturization, can be well adapted to industrial robot 3D printing equipment of different models, and is wide in applicability.

3. The printing method based on the high-precision 3D printing device has an automatic control function, the compensation in the whole printing process can be automatically carried out, the compensation efficiency is improved, the use threshold is reduced, and the market potential of the printing device is increased.

4. Compared with the traditional 3D printing device, the three-dimensional printing device adopts the industrial robot with more degrees of freedom, so that 3D printing of the curved surface part can be better performed, and the limitation of plane printing is broken through.

Drawings

FIG. 1 is a schematic structural diagram of a high-precision 3D printing device according to the present invention;

FIG. 2 is a flow chart of a printing method of the high-precision 3D printing device according to the invention;

reference numerals:

1-industrial robot, 2-six-axis parallel platform compensation mechanism, 3-camera adjusting mechanism, 4-CCD camera, 5-connecting frame and 6-extrusion head.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

The high-precision 3D printing device provided by the invention mainly comprises four parts: an industrial robot motion system, a compensation system, a printing system and a vision system. In one embodiment, as shown in fig. 1, it comprises an industrial robot 1, a six-axis parallel platform compensation mechanism 2, a camera adjustment mechanism 3, a CCD camera 4, a stepper motor and link 5, a heating block and an extrusion head 6.

Industrial robot motion system: an industrial robot motion system consisting of an industrial robot and a control unit thereof is responsible for a main motion process in the 3D printing process, and sends a printing system and a vision system to a designated printing node. In some embodiments, the industrial robot may be a multi-axis tandem robot, and a six-axis tandem industrial robot is preferred because the printing of curved parts requires that the primary motion mechanism have at least six degrees of freedom, and the working space of the six-axis tandem industrial robot is relatively large. In some embodiments, the central control unit may be a control cabinet of the robot itself, or may be a higher-level industrial automation network in which a plurality of 3D printing devices or other related intelligent devices are present, and all the devices are controlled by an upper computer or a numerical control system.

The compensation system comprises: the printing error compensation device comprises a compensation mechanism, a printing support platform, a robot connecting platform, a control unit and a driving unit, and is responsible for compensating printing errors in the 3D printing process. In some embodiments, the compensation mechanism can be a single-axis or multi-axis serial or parallel platform, when a single-axis motion sliding platform is adopted, the highest precision can reach 10 μm, the error in a certain degree of freedom can be compensated to the level of 10 μm theoretically, and a six-axis parallel platform is the optimal choice, because the six-axis parallel platform has the advantages of high precision and multiple degrees of freedom, the highest repeated positioning precision can reach +/-0.75 μm, and meanwhile, the six-axis parallel platform has 6 degrees of freedom and can meet the requirement that the error in the six degrees of freedom can be compensated when the curved surface part is printed. The driving unit and the control unit are changed according to the type of the compensation mechanism, but the principle is always to drive the motion mechanism with each degree of freedom, and the driving unit comprises but is not limited to a stepping motor and a servo motor; taking a single-axis motion sliding table as an example, the control unit of the motion sliding table includes, but is not limited to, a motion control card and a PLC; taking a six-axis parallel platform as an example, the control unit includes but is not limited to a programmable motion controller, a PLC, and a single chip.

A vision system: the vision system is responsible for observing the position and the attitude of the printing head in the 3D printing process, then calculates the position and attitude deviation and sends the position and attitude deviation to the compensation system, and the compensation mechanism carries out printing head compensation according to the compensation quantity. In some embodiments, the compensation is based on adjusting TCP (TCP pose information, i.e. end pose information, in the robot coordinate system) and substrate position information actually obtained by the vision system, and the compensation can make the position relationship between TCP and substrate achieve the best printing effect. The vision system mainly comprises a camera, a target or a machine learning unit and an image processing unit, in some embodiments, pose information is acquired by an industrial camera or a depth camera and the target, and the mode has the advantages of lowest cost, relatively higher flexibility and relatively controllable precision. In other embodiments, a laser tracker target ball and an image processing unit may also be used as a vision system. In other embodiments, a machine learning unit is used to help the camera acquire pose information. The image processing unit processes the obtained image information into pose information of the tail end of the printing head, compares the pose information with a theoretical pose input in advance, and sends different compensation information according to the design of a compensation system.

A printing system: the printing system is responsible for printing the consumptive material on the base plate after handling at 3D printing in-process, and the successive layer forms the structure. Engineering plastics, resin-based electrodes, carbon fiber reinforced composite materials and the like can be printed by the printing system due to different consumable materials, and the structure of the printing system can be adjusted according to different printing tasks. In one embodiment, a printing system includes a printhead, an extrusion unit, a heating unit, and a heat dissipation unit. The control units of the printing system are also different from each other in terms of their specific configurations. For example, in the process of laying carbon fiber prepreg, the control unit needs to control the refeed device on the printing head to convey the consumable material, needs to control the pneumatic element to cut the consumable material, needs to control the temperature control element to preheat the consumable material, and the like.

Based on the high-precision 3D printing device provided by the invention, a high-precision 3D printing method is also designed, and the method specifically comprises the following steps:

s1, according to the established three-dimensional model of the piece to be printed, the six-axis serial industrial robot moves the compensating system at the tail end of the six-axis serial industrial robot to a designated printing node;

s2, collecting the position and attitude information of the printing head through a vision system on a printing support platform of the compensation system, processing the data by an image processing unit to obtain the compensation amount and sending the compensation amount to the compensation system;

s3, the six-axis parallel platform compensation mechanism drives the printing system arranged on the printing support platform to move according to the compensation amount to complete compensation;

s4, the vision system collects the compensated position and attitude information of the printing head and evaluates the compensation precision;

the S5 printing system implements a 3D print job;

s6 after the printing node finishes the printing work, the industrial robot moves the compensating system at the tail end of the industrial robot to the next printing node;

s7 repeats steps S2-S5 until the to-be-printed piece is printed and molded.

The above-mentioned embodiments are merely specific embodiments of the present invention, which are used to illustrate the technical solutions of the present invention, but not to limit the technical solutions, and the scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the above-mentioned embodiments. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the invention without departing from the principle of the invention, and those improvements and modifications also fall within the scope of the claims of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.