A control system for a ceramic multi-material light-cured additive manufacturing apparatus

Abstract

This invention relates to a control system for ceramic multi-material photopolymer additive manufacturing equipment. It includes a hierarchical planning layer, a control layer, and an execution layer. The planning layer is signal-connected to the control layer, and the control layer is signal-connected to the execution layer. Specifically, the control system is divided into a three-layer architecture: planning, control, and execution. This three-layer architecture has clear hierarchy and division of labor, which is beneficial to improving overall control efficiency. The planning layer uses an extended G-code instruction set to describe the multi-material ceramic multi-process continuous forming process, solving the problem of convenient control instruction description. The control layer selects suitable controllers and supporting components to meet the interface requirements of various types of actuators, receives control instructions from the planning layer, and converts them into action signals for the actuators. After receiving the action signals, the actuators in the execution layer perform the corresponding printing actions, realizing full-process control of ceramic multi-material photopolymer additive manufacturing.

Description

Technical Field

[0001] This invention relates to a control system for ceramic multi-material photopolymer additive manufacturing equipment. It is applied to the invocation and coordinated control of various actuators within the ceramic multi-material photopolymer additive manufacturing equipment. Background Technology

[0002] The demand for multi-material photopolymer additive manufacturing equipment for ceramic components, particularly those with complex and irregular shapes, is urgent in key fields such as biomedicine and aerospace. Existing ceramic additive manufacturing equipment suffers from problems such as easy mixing of multiple materials, low forming accuracy, and low material changeover printing efficiency, hindering the efficient and precise forming of multi-material, heterogeneous, and complex ceramic components and significantly limiting their application potential. A ceramic multi-material photopolymer additive manufacturing system that integrates multi-material feeding and leveling processes, photopolymerization and release processes, paste recovery processes, release film cleaning and drying processes, and preform cleaning processes holds promise for achieving efficient and precise forming of multi-material, heterogeneous, and complex ceramic components.

[0003] However, ceramic multi-material photopolymer additive manufacturing equipment comprises five sub-process modules, each containing numerous actuators with varying electrical interfaces and control methods. Traditional single-controller systems, such as microcontrollers, Arduino, and Raspberry Pi, have complex and time-consuming development processes, and their interfaces are difficult to accommodate the diverse types of actuators. Furthermore, existing equipment control systems mostly rely on manual button presses for control commands; however, the ceramic multi-material photopolymer additive manufacturing process requires complex coordination among multiple processes and actuators, resulting in complex coupling of control commands. Large-format forming also necessitates multiple stitching operations, leading to lengthy printing times. Manual control would place a significant burden on operators. Therefore, these control methods are no longer suitable for ceramic multi-material photopolymer additive manufacturing equipment due to interface type mismatches and the lack of ease of command description.

[0004] Therefore, how to accurately describe the multi-material ceramic multi-process continuous forming process with control commands, how to select and match controllers to adapt to various types of actuator electrical interfaces, and how to receive control commands and convert them into actuator actions, so as to realize multi-material ceramic multi-process continuous forming, are still key issues that urgently need to be solved. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems and provide a control system for ceramic multi-material photopolymer additive manufacturing equipment. This system is applied to the invocation and coordinated control of various actuators in ceramic multi-material continuous forming photopolymer additive manufacturing equipment, thereby realizing the various process flows of the equipment and achieving efficient and precise forming of multi-material heterogeneous and complex irregular-shaped ceramic components.

[0006] A control system for a ceramic multi-material photopolymer additive manufacturing equipment includes a hierarchical planning layer, a control layer, and an execution layer. The planning layer is signal-connected to the control layer, and the control layer is signal-connected to the execution layer. Specifically, the control system is divided into a three-layer architecture of planning, control, and execution. This three-layer architecture has clear hierarchy and division of labor, which is conducive to improving overall control efficiency. The planning layer uses an extended G-code instruction set to describe the multi-material ceramic multi-process continuous forming process, solving the problem of convenient control instruction description. The control layer selects suitable controllers and supporting components to meet the interface requirements of various types of actuators, receives control instructions from the planning layer, and converts them into action signals for the actuators. After receiving the action signals, the actuators in the execution layer perform the corresponding printing actions, realizing full-process control of ceramic multi-material photopolymer additive manufacturing.

[0007] The control system also includes a host computer and a bus-type motion control card. The host computer constitutes the hardware carrier of the planning layer, and the bus-type motion control card constitutes the core hardware of the control layer. The planning layer is used to plan the control instructions required during the printing process based on the 3D model of the printed part before printing, and to process the model slice data. The control layer is used to receive the control instructions from the planning layer and convert them into various control signals to be output to the execution layer. The execution layer is used to receive the control signals from the control layer and execute the corresponding actions of ceramic multi-material photopolymer additive manufacturing. The host computer and the bus-type motion control card achieve bidirectional signal transmission via Ethernet. The host computer and the DLP optical engine's built-in control board transmit data and communicate via HDMI data cable and USB serial port.

[0008] The control commands generated by the planning layer include the image data to be projected by the optical engine, standard G-code, and custom M-code. The standard G-code refers to the G-code conforming to the DIN66025 standard, which is used to control the XYZ coordinate axes of the displacement mechanism, the A-axis of the conveyor belt, and the D-axis of the rotary table to achieve multi-axis linkage CNC motion control. The custom M-code is used to implement the auxiliary function of switching material feeding. The standard G-code and the custom M-code are collectively referred to as extended G-code.

[0009] The lower-level supporting hardware of the control layer transmits signals to the execution layer hardware via circuit connections. The control signals output by the control layer to the execution layer include current signals and switching signals. The lower-level supporting hardware of the control layer includes drivers and relays. The bus-type motion control card transmits signals to the driver hardware components via an EtherCAT bus and to the relay hardware components via a circuit interface. The driver converts the position and speed signals sent by the bus-type motion control card into current signals to drive the moving parts of the execution layer. The relays are used to control the switching of the electrical components of the execution layer. The control layer is functionally divided into three parts: projection control, motion control, and auxiliary function control. The hardware of the projection control board is provided by the optical engine manufacturer and integrated with the optical engine. The software needs to be written in C++ in the QT development environment to implement the projection display, light intensity, and start / stop control of the optical engine. The motion control part reads standard G-code to control the displacement mechanism, rotary table, and conveyor belt for CNC motion. The auxiliary function control part reads custom M-code to control the on / off state of the relays.

[0010] The execution layer integrates the execution mechanisms of the five sub-process modules of the multi-material ceramic additive manufacturing equipment. According to the control method, they are divided into three categories: optomechanical, motor, and relay. At the same time, the execution layer is divided into motion module, projection module, and switch module according to function. The three modules independently receive control signals from the control layer and execute actions to achieve coordinated cooperation.

[0011] The motion module includes motors for the XY axes of the displacement module and the D axis of the rotary table. Specifically, the motion axis motors are stepper motors for the XY axes of the displacement mechanism, rotary servo motors with ball screws for the ZBC axes, and DD motors for the D axis of the rotary table. The ZBC axes of the displacement mechanism are equipped with incremental grating rulers to achieve closed-loop control, and these motors are equipped with EtherCAT bus-type drivers. The motion axis motors are connected to the drivers in the control layer via circuitry. The drivers drive the motion axis motors to rotate, thereby driving the XY axes of the displacement module and the D axis of the rotary table to complete precise positioning. The XY axes of the displacement module and the D axis of the rotary table in the execution layer are controllable continuous motion components. In the control layer, the bus-type motion control card outputs precise position and speed information to the drivers according to the control instructions from the planning layer. The drivers then precisely control the current in the motors in the execution layer via circuitry, thereby achieving high-precision displacement and rotation movements and completing high-precision motion control in the ceramic multi-material photopolymerization additive manufacturing process.

[0012] The projection module is a DLP optical engine. This is a static DLP optical engine with its own control board, which connects directly to the host computer. The host computer sends the image information to be projected to the optical engine control board via an HDMI cable and sends information such as projection light intensity and projection start / stop via a USB serial port. When the optical engine is set as an extended screen for the host computer, the content displayed on the extended screen is the image projected by the optical engine. The host computer controls the projected image via an HDMI cable, and the start / stop and brightness of the optical engine are controlled by the host computer sending commands to the optical engine's built-in control board via serial communication.

[0013] The switching module includes a dispensing valve, which is connected to a relay in the control layer via a circuit. The relay receives on / off information from the circuit interface of the upper-level bus-type control card and realizes the switching control of the dispensing valve, adapting to the feeding needs of multiple ceramic materials. The relay also controls the on / off of the power supply. Other actuators in each process module that require switching control are also connected to the relay, and the relay realizes the switching control in a unified manner. These will not be shown here.

[0014] The beneficial effects of the control system of the ceramic multi-material photopolymer additive manufacturing equipment of the present invention are:

[0015] This invention discloses a control system for ceramic multi-material photopolymer additive manufacturing equipment. Through a modular design with a three-layer architecture, the system has clear hierarchy and division of labor, thereby improving overall control efficiency.

[0016] The planning layer uses an extended G-code instruction set to describe the multi-material ceramic multi-process continuous forming process, which solves the problem of the convenience of control instruction description, that is, how to describe the multi-material ceramic multi-process continuous forming process with simple instructions rather than button operations.

[0017] The planning layer can be performed before printing begins. It can generate all the extended G-code instructions needed during the printing process and integrate them into a single tex file. When printing, the operator only needs to open the tex file and then click "Run continuously" to execute the extended G-code instruction set line by line. This avoids button-based operations for the operator during the printing process and effectively reduces the operator's workload.

[0018] The control layer selects suitable controllers and supporting components to meet the interface requirements of various types of actuators, avoiding the circuit board design steps of using microcontrollers and other controllers, thereby simplifying the controller hardware construction process and shortening the development cycle.

[0019] This control system solves the technical problems of low motion control accuracy and weak multi-process coordination by precisely matching the planning and control layer hardware and software with the execution layer hardware, and realizes efficient, precise and full-process control of continuous forming of ceramic multi-materials. Attached Figure Description

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0021] Figure 1 Control architecture for ceramic multi-material photopolymer additive manufacturing equipment;

[0022] Figure 2 This is a schematic diagram of the hardware setup for the control system. Detailed Implementation

[0023] The following is in conjunction with the appendix Figure 1-2 The specific implementation of the control system of the ceramic multi-material photopolymer additive manufacturing equipment of the present invention is described in detail. This implementation is only used to explain the present invention and is not intended to limit the scope of protection of the present invention.

[0024] The control system for ceramic multi-material continuous forming photopolymer additive manufacturing equipment proposed in this invention adopts a three-layer control architecture consisting of a planning layer, a control layer, and an execution layer, such as... Figure 1 As shown, the three-layer architecture has a clear division of labor and works together to achieve precise control of the entire process of ceramic multi-material photopolymer additive manufacturing. The core function of the planning layer is to output control commands, the core function of the control layer is to receive and parse the control commands and convert them into control signals that can be recognized by the actuators, and the core function of the execution layer is to receive control signals and complete specific printing actions.

[0025] The hardware structure of the control system of this invention is as follows: Figure 2 As shown, the supporting hardware at each level is connected according to its functions, and the software of the control system is written in C++ in the QT software of the host computer. It can directly call the DLP optical engine function and the function library of the bus-type motion control card to realize the coordinated control of software and hardware. Among them, the preprocessing module of the printed model is the core execution unit of the planning layer, the host computer is the hardware carrier of the planning layer, the control layer consists of the host bus-type motion control card and its lower-level supporting drivers and relays, and the execution layer integrates the motion axis motor, dispensing valve and DLP optical engine execution mechanism.

[0026] The signal connection methods of each hardware component are as follows: The host computer interacts bidirectionally with the DLP optical engine through HDMI interface and serial communication, thereby precisely controlling the projected image, on / off status and brightness parameters of the DLP optical engine; the host computer also interacts with the bus-type motion control card through Ethernet. The EtherCAT bus interface of the bus-type motion control card is adapted to connect with the motion axis motor driver, and its switch interface is adapted to connect with the relay, meeting the interface requirements of multiple types of actuators and realizing stable transmission of control signals.

[0027] The control system of the ceramic multi-material photocuring additive manufacturing equipment of the present invention implements the photocuring additive manufacturing control of ceramic multi-materials through the following steps, the specific steps of which are as follows:

[0028] Step 1:

[0029] Before printing begins, the planning layer plans and generates all process control instructions based on the 3D model of the printout:

[0030] The 3D model of the printed part is sliced ​​using DLP slicing software (such as Autodesk Netfabb Standard 2019) to obtain single-layer slice images of the printed part;

[0031] Using image segmentation software developed in Python, the above single-layer slice image is segmented according to the image splicing and moving path to obtain the image sequence required for projection by the DLP optical engine;

[0032] Based on the process flow of single-layer printing, all actions to be performed in the process are described using extended G-code, forming the single-layer printing process extended G-code;

[0033] Based on the extended G-code of the single-layer printing process, G-code corresponding to the interlayer preform cleaning process is added. Then, using multi-layer process planning software developed based on Python, the single-layer printing process G-code is copied and extended to all layers required for printing, ultimately forming a complete multi-layer extended G-code file for the printed part. This file specifies all the action instructions that the ceramic multi-material additive manufacturing equipment needs to execute during the printing process.

[0034] Step 2:

[0035] After printing begins, the control layer reads, categorizes, and parses the control instructions generated by the planning layer line by line, and converts them into control signals that can be received by the corresponding actuators.

[0036] The projection control part of the control layer directly reads the image data generated by the planning layer, and at the same time sends the light intensity and exposure time projection parameters to the DLP optical engine to achieve precise projection control of the DLP optical engine;

[0037] The extended G-code generated by the planning layer is a text file in tex format, in which standard G-code and custom M-code coexist. The control layer reads and parses it according to the rule of line-by-line order.

[0038] When the control layer reads the standard G code, the motion control part parses the instruction and outputs control signals to control the XYZ axes of the displacement mechanism, the D axis of the rotary table, and the B and C axes of the material changing axis, thereby realizing the multi-axis linkage interpolation motion control of the above axes.

[0039] When the control layer reads the custom M code, the auxiliary function control part parses the instruction and outputs a switch signal to realize the on / off control of various auxiliary actions.

[0040] Step 3:

[0041] After receiving the corresponding control signals output by the control layer, each execution mechanism in the execution layer synchronously executes the specific printing action;

[0042] After receiving the projection command from the host computer, the DLP optical engine projects the specified image sequence according to the light intensity and exposure time specified in the command, thus completing the projection process of light curing.

[0043] After receiving the position coordinate commands sent by the control layer, the XYZ axes of the displacement mechanism, the D axis of the rotary table, the B and C axes of the material changing axis generate corresponding currents according to the commands, drive the motors of each axis to run, and move the axis precisely to the designated position.

[0044] After receiving the on / off information from the control layer circuit interface, the relay controls the power supply according to the information, thereby driving the dispensing valve and the actuator that needs to be switched to complete the corresponding auxiliary actions, adapting to the feeding and cleaning process requirements of multiple ceramic materials.

Claims

1. A control system of a ceramic multi-material light solidification additive manufacturing apparatus, characterized in that, It includes a hierarchical planning layer, a control layer, and an execution layer, wherein the planning layer is signal-connected to the control layer, and the control layer is signal-connected to the execution layer; The control system also includes hardware such as a host computer, a bus-type motion control card, drivers, and relays; the host computer constitutes the hardware carrier of the planning layer; the bus-type motion control card constitutes the upper core hardware of the control layer; the drivers and relays constitute the lower supporting components of the control layer; the DLP optical engine, motion axis motor, and dispensing valve are the hardware carriers of the execution layer. The software carriers of the planning layer include commercial DLP slicing software installed on the host computer operating system, image segmentation software developed based on Python, and multi-layer process planning software developed based on Python; the software carriers of the control layer include integrated control software developed using C++ and based on the QT development environment installed on the host computer operating system. The planning layer is used to process model slice data and generate control commands. The control layer is used to receive the control commands from the planning layer and convert them into various control signals to be output to the execution layer. The execution layer is used to receive the control signals from the control layer and execute the corresponding actions of ceramic multi-material photopolymer additive manufacturing.

2. The control system of a ceramic multi-material light solidification additive manufacturing apparatus according to claim 1, characterized in that, The control instructions generated by the planning layer include standard G-codes and custom M-codes.

3. The control system of a ceramic multi-material light solidification additive manufacturing apparatus according to claim 1, characterized in that, The host computer and the bus-type motion control card achieve bidirectional signal transmission via Ethernet; the host computer and the DLP optical engine's built-in control board transmit data and communicate via HDMI data cable and USB serial port.

4. The control system of a ceramic multi-material light solidification additive manufacturing apparatus according to claim 1, wherein, The lower-level supporting hardware of the control layer transmits signals to the execution layer hardware through circuit connection. The control signals output by the control layer to the execution layer include current signals and switching signals.

5. The control system of the ceramic multi-material photopolymer additive manufacturing equipment according to claim 1, characterized in that, The control layer also includes lower-level supporting hardware drivers and relays. The bus-type operation control card transmits signals with the driver hardware components via the EtherCAT bus and with the relay hardware components via the circuit interface. The driver is used to convert the position and speed signals sent by the bus-type motion control card into current signals to drive the moving parts of the execution layer. The relay is used to realize the switching control of the electrical components of the execution layer.

6. The control system of the ceramic multi-material photopolymer additive manufacturing equipment according to claim 1, characterized in that, The execution layer is divided into a motion module, a projection module, and a switch module according to their functions. The three modules independently receive control signals from the control layer and execute corresponding actions to achieve coordinated cooperation.

7. The control system of the ceramic multi-material photopolymer additive manufacturing equipment according to claim 6, characterized in that, The motion module includes motors for the XY axes of the displacement module and the D axis of the rotary table. The motors of the motion axes are connected to the driver signals of the control layer. The driver drives the motors of the motion axes to rotate, thereby driving the movers of the XY axes of the displacement module and the D axis of the rotary table to complete precise positioning.

8. The control system of the ceramic multi-material photopolymer additive manufacturing equipment according to claim 6, characterized in that, The projection module is a DLP optical engine. The DLP optical engine has a control board provided by the manufacturer and is directly connected to the host computer. The host computer sends the image information to be projected to the optical engine control board via an HDMI data cable and sends information such as projection light intensity and projection start / stop via a USB serial port.

9. The control system of the ceramic multi-material photopolymer additive manufacturing equipment according to claim 6, characterized in that, The switching module includes a dispensing valve switch, which is connected to a relay signal in the control layer. The relay receives the on / off signal from the control layer circuit interface and realizes the on / off control of the dispensing valve, adapting to the feeding needs of multiple ceramic materials.

10. The control system of the ceramic multi-material photopolymer additive manufacturing equipment according to any one of claims 1-9, characterized in that, The displacement module XY axis and rotary table D axis of the execution layer are controllable and continuously moving components. The control layer outputs precise displacement and rotation control signals to the execution layer based on the model slices and process planning data of the planning layer, so as to realize high-precision molding control of ceramic multi-material photopolymer additive manufacturing.

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