Automatic leveling device and system for 3D printing

Abstract

The invention discloses an automatic leveling device and system for 3D printing, and belongs to the technical field of additive manufacturing. The device comprises a rack, an X / Y / Z three-axis module, a spray head assembly, a printing substrate, an automatic leveling module, a camera module and a controller, and the leveling module integrates a laser distance measuring sensor and visual identification equipment and is used for collecting the height of the substrate and outputting Z-axis compensation data. A data processing and fitting module matched with the system is deployed on an upper computer and has the functions of abnormal data removal and polynomial curve fitting, and a control module achieves three-axis cooperative movement based on a CAN bus and adjusts the Z-axis position of a nozzle in real time. High-precision and multi-point Z-axis dynamic compensation is achieved, automatic leveling in the whole process is supported, the device adapts to complex deformation of the substrate, the printing quality and the automation level of equipment are remarkably improved, and the device is suitable for various industrial or desktop-level 3D printing equipment.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing technology, and in particular to an automatic leveling device and system suitable for 3D printing equipment, specifically a high-precision dynamic compensation leveling technology that combines laser ranging, visual recognition and three-axis motion control. Background Art

[0002] During 3D printing, controlling the distance between the nozzle and the substrate plays a crucial role in determining print quality. Improper leveling can lead to material accumulation, stringing, faulting, and even scratches that damage the equipment. Existing leveling technologies fall into two main categories: manual leveling, which relies on manual experience and is inefficient and subject to large errors; and static compensation based on single- or multi-point sampling, which cannot adapt to subtle dynamic changes in the substrate during printing, such as thermal deformation. Therefore, a new leveling technology that enables high-precision measurement, multi-point modeling, and dynamic real-time compensation is urgently needed to meet the demands of high-quality, complex-shape, and batch printing. Summary of the Invention

[0003] The purpose of the present invention is to provide a 3D printing automatic leveling device and system to solve the problems of low precision, slow response and manual dependence of traditional leveling methods, realize dynamic compensation of the distance between the nozzle and the substrate throughout the printing process, and improve printing quality and automation level.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A 3D printing automatic leveling device, comprising:

[0006] A frame for supporting the entire structure of the printing device;

[0007] An X-axis module, provided on the frame, for driving the print head to move along the X-axis direction;

[0008] a Y-axis module connected to a printing substrate, the Y-axis module being used to drive the substrate to move along the Y-axis direction;

[0009] A Z-axis module connected to a nozzle assembly, the Z-axis module is used to control the lifting and lowering of the nozzle in the Z-axis direction;

[0010] An automatic leveling module, located near the printhead or above the frame, includes a laser distance sensor, a limit switch, or a visual recognition device to detect the substrate height and output Z-axis compensation data. The accuracy of the laser distance sensor is 10 μm.

[0011] A camera module is disposed on one edge of the substrate, and the camera module mainly includes an industrial camera with a resolution of at least 2592×1944;

[0012] A controller that receives printing path and leveling data, drives each axis to perform corresponding movements, and controls the feeding rhythm of the printing material.

[0013] The print head assembly is mounted on the Z-axis module and includes a material heating and extrusion mechanism.

[0014] The printing substrate is located below the nozzle and is used to receive the printing material.

[0015] A 3D printing automatic leveling system, comprising the above device and:

[0016] The data processing and fitting module is deployed in the host computer software to receive laser ranging data, perform noise reduction, anomaly elimination and polynomial curve fitting operations, and generate the Z-axis compensation path. The control module uses a three-axis control chip and realizes three-axis coordinated motion based on CAN bus communication;

[0017] The host computer sends the printing path including the Z-axis compensation value to the control module, realizing real-time automatic adjustment of the distance between the nozzle and the substrate during the printing process.

[0018] The system proposed by the present invention follows the following working steps when working:

[0019] 1. Initialization: Set a reference point on the substrate, move the laser ranging sensor above the reference point, collect the height L1, then move the dispensing needle to the calibration position, lower the Z axis until the needle touches the substrate, and measure the relative position h between the needle and the laser sensor in the Z axis direction.

[0020] 2. Pre-sampling: The print head moves along the path, and the laser ranging sensor samples several height data L1 of the print head in the Z-axis direction; the camera observes the actual height L2 and establishes a mapping relationship;

[0021] 3. Data fitting: Eliminate abnormal jump points and generate compensation paths through fitting;

[0022] 4. Execute printing: The compensated path command controls the Z-axis of the nozzle to adjust in real time to achieve automatic leveling.

[0023] The first step is to calibrate the relative distance between the needle and the laser. After calibration, the laser pre-path stage will be carried out.

[0024] The calibration method is: select a certain point on the substrate as the calibration point, lower the Z axis to a certain height, read the laser reading, and then perform the laser pre-travel.

[0025] Compared with the existing technology, the present invention has the following advantages: it supports high-precision, multi-point dynamic compensation and adapts to complex deformation of the substrate; the entire leveling process is automatically executed, reducing manual intervention; laser + vision fusion makes measurement more accurate; the system can be integrated into various industrial / desktop 3D printing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of the 3D printing automatic leveling device of the present invention;

[0027] Figure 2 This is a schematic diagram showing the partial structure of the 3D printing automatic leveling device of the present invention;

[0028] Figure 3 This is a diagram of the architecture of the 3D printing automatic leveling system of the present invention.

[0029] 1. Frame 13, frame 14, top cover 2, printing substrate 32, stepping motor 31, ball screw 41, screw 61, dispensing needle 71, laser ranging sensor 81, camera module. DETAILED DESCRIPTION

[0030] In this embodiment, the system includes the following specific configurations:

[0031] Component Configuration 5

[0032] A laser rangefinder Keyence

[0033] An industrial camera Daheng

[0034] A control host high-performance PC (i5+8GB memory)

[0035] The system's motion control module features an STMicroelectronics STM32 main control chip and a CMOSIC TC6014 three-axis motion control chip. Communication is via the CAN bus. The motion control module precisely controls the movement of the print head in the X, Y, and Z directions, enabling path-compensated motion control. The X, Y, and Z-axis modules are all self-assembled, utilizing a drive mechanism consisting of a stepper motor and ball screw.

[0036] like Figure 1As shown, in this embodiment, the automatic leveling 3D printing device includes a frame 1, which is used to accommodate and install an X-axis module, a Y-axis module, and a Z-axis module. The frame structure of the frame 1 enables the above three modules to control the strokes in the X, Y, and Z directions respectively, forming a stroke system of a three-axis printing system. The X-axis module is arranged on the frame 1, and is used to drive the Z-axis module to move along the X direction through a stepper motor 32 and a ball screw 31. The Y-axis module is connected to a printing substrate 2, and the printing substrate 2 is accommodated in a frame 13 on the frame 1. The Y-axis module also uses a stepper motor and a screw 41 to drive the substrate 2 to move along the Y direction. The Z-axis module is connected to the nozzle assembly, and the nozzle is also controlled to rise and fall in the vertical direction, i.e., the Z direction, through a stepper motor and a ball screw. As shown Figure 2 As shown, a laser rangefinder sensor 71 is mounted next to the 3D printer's dispensing needle 61, while the industrial camera included in the camera module 81 is mounted within the frame 13, on the outer edge of the side facing the non-moving direction of the substrate 2. The dispensing needle 61 is a functional component of the nozzle assembly, which also includes a dispensing nozzle or a 3D printing nozzle. The dispensing needle and nozzle are interchangeable, but their lower end surfaces in the Z-axis direction are flush.

[0037] After the system of this embodiment is started, the host computer implements its leveling function through the following steps.

[0038] Initialization: Set a reference point on the substrate 2, move the laser distance sensor to above the reference point, collect the height L1, then move the dispensing needle to the calibration position, lower the Z axis until the needle touches the substrate, and measure the relative position h of the dispensing needle 61 and the laser distance sensor 71 in the Z axis direction.

[0039] Afterwards, the laser ranging sensor collects the original height L, which is the height data compensated after the system has considered the relative position h;

[0040] The actual height observed by the camera is L actual For calibration;

[0041] Establish the mapping relationship between the original laser height and the true height:

[0042] Compare the laser ranging sensor output value L with the actual height value L actual , fitting calibration function L actual =f(L)=a o +a1L+a2L 2 +…

[0043] 2. Laser pre-path stage: The print head "pre-travels" according to the set path; the laser ranging sensor records the Z-axis distance data of each point on the path in real time.

[0044] 3. Data processing and path compensation stage: The host computer performs noise reduction, outlier removal and curve fitting on these data.

[0045] In this embodiment, we consider that the laser distance sensor often causes transient measurement errors during the acquisition process due to surface reflection or transparent materials, local edge effects, laser beam angle changes, and jitter, resulting in abnormal jump points. If left untreated, this will cause drastic fluctuations in path height, affecting printing accuracy. Therefore, this project uses the following method to filter data. Assume that the original point sequence is: {(x i, y i ,z i )} i n =1, let the first point Z0 = Z1, if there are K or more consecutive points satisfying: |Z i -Z0|>e, then a segment of data is cut out from the current sequence, the stable segment is retained, and grouping is restarted. e is the maximum deviation allowed between the z value and the reference height z, generally 0.03-0.1mm. The Z value after cleaning is distributed in a two-dimensional space (xy). There is nonlinear fluctuation in the Z axis, so a two-dimensional polynomial fitting is required to generate a smooth and continuous surface model Z=f(x, y) for subsequent path Z axis compensation. The specific fitting method is: For example, a fifth-order fit (d=5) would include the following items: 1, x, y, x 2 ,xy,y 2 ,…,x 5 , x 4 y, x 3 y 2 ,…,y 5 ,The model highly fuses the original motion path with the compensation to generate a new motion ,code.

[0046] 4. Print execution phase: Issue Z-compensated motion instructions; automatically compensate the Z value of each point during the actual printing process; ensure a constant distance between the needle and the substrate, and improve dispensing / printing accuracy.

Claims

1. A 3D printing automatic leveling device, characterized in that: include: A frame for supporting the entire structure of the printing device; An X-axis module, disposed on the frame, for driving the printhead to move along the X-axis direction; a Y-axis module connected to a printing substrate, the Y-axis module being used to drive the substrate to move along the Y-axis direction; A Z-axis module connected to a nozzle assembly, the Z-axis module is used to control the lifting and lowering of the nozzle in the Z-axis direction; an automatic leveling module, disposed near the printhead or above the frame, comprising a laser range sensor, a limit switch or a visual recognition device, for detecting the height of the substrate and outputting Z-axis compensation data; a camera module, disposed on one edge of the substrate; A controller, configured to receive printing path and leveling data, drive each axis to perform corresponding motion, and control the feeding rhythm of the printing material; The nozzle assembly is arranged on the Z-axis module and includes a material heating and extrusion mechanism; the printing substrate is located below the nozzle and is used to receive the printing material.

2. The 3D printing automatic leveling device according to claim 1, characterized in that: The laser distance sensor has a measurement accuracy of 10 μm and a response time of 10 ms.

3. The 3D printing automatic leveling device according to claim 1, characterized in that: The resolution of the camera in the camera module is 2592×1944, which is used to collect image data between the nozzle and the substrate and perform position calibration.

4. The 3D printing automatic leveling device according to claim 1, characterized in that: The nozzle assembly is a dispensing nozzle or a 3D printing nozzle or a dispensing needle, which is suitable for additive manufacturing processes.

5. A 3D printing automatic leveling system, characterized by: The automatic leveling device according to any one of claims 1 to 5, further comprising: The data processing and fitting module is deployed in the host computer and is used to receive laser ranging data, perform noise reduction, anomaly removal and polynomial curve fitting operations, and generate the Z-axis compensation path; The control module adopts a three-axis control chip and realizes three-axis coordinated motion based on CAN bus communication; the host computer sends a printing path including a Z-axis compensation value to the control module to realize real-time automatic adjustment of the distance between the nozzle and the substrate during the printing process.

6. The system according to claim 5, characterized in that: The system can automatically establish a mapping relationship between the original height of the laser and the actual height observed by the camera for laser calibration; the control module supports G-code motion instruction parsing and integrates Z-axis compensation data to output update instructions.

7. The system according to claim 6, characterized in that: The system comprises the following steps when running:

1. Initialization: Set a reference point on the substrate, move the laser ranging sensor above the reference point, collect the height L1, then move the dispensing needle to the calibration position, lower the Z axis until the needle touches the substrate, and measure the relative position of the needle and the laser sensor in the Z axis direction; 2. Pre-sampling: The print head moves along the path, and the laser ranging sensor samples several height data L1 of the print head in the Z-axis direction; the camera observes the actual height L2 and establishes a mapping relationship; 3. Data fitting: Eliminate abnormal jump points and generate compensation paths through fitting; 4. Execute printing: The compensated path command controls the Z-axis of the nozzle to adjust in real time to achieve automatic leveling.

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