Bipolar coordinate 3D printer and control method thereof

Abstract

The invention provides a bipolar coordinate 3D printer which comprises a fixing base, a rotary table, a swing arm, a ZR driving assembly and a printing head assembly, the rotary table is provided with a carrying table surface which is used for receiving printing materials and can horizontally rotate, a movement mechanism of the ZR driving assembly is fixedly connected with one end of the swing arm, and the printing head assembly is arranged at the other end of the swing arm. The ZR driving assembly drives the swing arm to do vertical rectilinear motion and horizontal rotating motion and drives the printing head assembly to do rectilinear motion in the vertical direction and do arc motion in the horizontal direction, and the projection perpendicular line of the arc motion of a material extrusion opening of the printing head assembly covers the rotating center point of the surface of the carrying table to the outer edge. And three-dimensional printing covering the surface of the carrying table and the vertical space is achieved by rotating the surface of the carrying table and swinging and vertical movement of a material extrusion opening. The bipolar coordinate 3D printer has the advantages of being simple in structure, small in occupied space and easy and convenient to assemble and maintain.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printers, and particularly to a material extrusion 3D printer with a bipolar coordinate structure and a control method thereof. Background Art

[0002] Existing material extrusion 3D printers mainly include gantry structures, Cartesian coordinate structures, parallel-arm delta structures, and polar coordinate structures. Gantry structures and Cartesian coordinate structures adopt the XYZ three-rectangular coordinate motion scheme. The print head generally moves along two coordinate directions, and the print platform moves along the other coordinate direction. A structural framework is required to support and limit each moving part. Its printing space is usually limited by the support framework, with a relatively complex structure, many components, difficult assembly and maintenance, and lack of flexibility in installation and layout. At the same time, due to the large moment of inertia of the print platform, it is difficult to improve the printing speed, and it is not suitable for high-speed printing. Although the parallel-arm delta structure can use a print platform with a fixed position, it is necessary to leave a linear movement space for the three parallel arms, which occupies a large space in the height direction and has low space utilization. The polar coordinate structure adopts a polar coordinate system, which consists of a rotating platform (R), a vertical axis (Z), and a horizontal axis (Y). The driving mechanism of the horizontal axis (Y) needs to move with the vertical axis (Z), and the linear movement mechanism has more components and a relatively complex structure. Summary of the Invention

[0003] The main purpose of the present invention is to provide a bipolar coordinate 3D printer to solve the deficiencies in the prior art.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is to provide a bipolar coordinate 3D printer, including a fixed base, a turntable, a ZR driving assembly, a swing arm, and a print head assembly.

[0005] The turntable and the ZR driving assembly are mechanically connected to the fixed base; the turntable at least includes a rotation driving assembly and a rotating platform. The rotation driving assembly drives the rotating platform to rotate, and the rotating platform is provided with a platform surface for receiving printing materials; the ZR driving assembly at least includes a ZR driving unit and a sliding sleeve. The ZR driving unit drives the sliding sleeve to perform linear motion in the vertical direction and rotational motion in the horizontal direction through a transmission shaft; one end of the swing arm is fixedly connected to the sliding sleeve, and the length direction of the swing arm is set to be rotatable along the horizontal direction with the sliding sleeve; the print head assembly is arranged at the other end of the swing arm, and the print head assembly is provided with at least one material extrusion port for conveying printing materials to the platform surface; the ZR driving assembly drives the swing arm to perform vertical linear motion and horizontal rotational motion, and the material extrusion port moves in an arc in the horizontal direction and in a straight line in the vertical direction with the swing arm; the projection of the movement trajectory of the material extrusion port on the horizontal plane is a continuous arc with the axis of the sliding sleeve as the center and passing through the center of the platform surface, which cooperates with the surface of the rotating platform, and its vertical projection covers all the effective printing areas of the platform surface.

[0006] Optionally, the ZR driving unit includes a rotary driving motor and a linear driving motor. The output shaft of the linear driving motor is a lead screw shaft and is provided with a matching lead screw nut. The rotary driving motor is arranged to drive a spline shaft, and the sliding sleeve is arranged as a spline shaft sleeve that mates with the spline shaft. The lead screw shaft is arranged in parallel with the spline shaft, and the lead screw nut is rotatably connected to the sliding sleeve through a connecting member.

[0007] Optionally, the ZR driving unit includes a rotary driving motor and a linear driving motor. The output shaft of the linear driving motor is a lead screw shaft and is provided with a matching lead screw nut. The rotary driving motor is arranged to drive a hollow shaft; the sliding sleeve is arranged as a sliding shaft sleeve that mates with the hollow shaft, and the hollow shaft is provided with an axially penetrating open linear groove; the lead screw shaft is coaxially arranged inside the hollow shaft, and the lead screw nut is accommodated inside the hollow shaft and is fixedly connected to the sliding sleeve through a connecting member disposed in the open linear groove.

[0008] Furthermore, the rotary driving assembly includes a reduction mechanism.

[0009] Optionally, the length of the swing arm is adjustable.

[0010] The technical solution adopted by the present invention also provides a control method for a bipolar coordinate 3D printer, including the steps of: a) Calculating the rotation angle of the turntable, the movement trajectory of the swing arm, and the extrusion amount of the print head according to the model data; b) Cooperatively controlling the ZR driving assembly and the movement of the turntable to print the material extrusion port along a preset trajectory.

[0011] Due to adopting the above technical solution, compared with the prior art, the present invention has the following beneficial effects: a) All driving motors related to the movement of the spatial coordinates are fixedly connected to the fixed seat and its bracket, and the moment of inertia of the end print head is low, the printing stability and transmission efficiency are high, and it is suitable for high-speed printing; b) Using a swing arm to replace the Y-axis linear driving mechanism of the traditional polar coordinate structure, the structure is simpler, and it is convenient for assembly and maintenance; c) The printing space is mainly related to the Z-direction stroke and the length of the swing arm. Except for the fixed seat and its bracket as the necessary structural support, the main body structure does not require an additional support frame, occupies less space, and is flexible in installation and layout; d) Adopting a composite structure of a lead screw shaft and a spline shaft to achieve a compact integration of rotation and linear motion; the coaxial design of the lead screw shaft and the hollow shaft further optimizes the space utilization rate. Description of the Drawings

[0012] Figure 1 is a schematic structural diagram of an embodiment of the bipolar coordinate 3D printer of the present invention.

[0013] Figure 2It is a schematic diagram of the printing principle of the bipolar coordinate 3D printer of the present invention.

[0014] Figure 3 It is a schematic structural diagram of an embodiment of a bipolar coordinate 3D printer using a coaxial ZR drive assembly.

[0015] Figure 4 It is a front view and a schematic structural cross-section diagram of the coaxial ZR drive assembly.

[0016] Figure 5 It is a flowchart of the control method of the bipolar coordinate 3D printer. Detailed implementation manners

[0017] In the following, the exemplary embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings. However, the same or similar elements are denoted by the same reference numerals regardless of the reference numerals, and their redundant descriptions will be omitted. In addition, when determining that the detailed description of the related known technology may obscure the key points of the embodiments disclosed in this specification, the detailed description thereof will be omitted.

[0018] When a component is referred to as being "connected" or "coupled" to another component, it can be understood that it can be directly connected or coupled to the other component, but other components may also be present in the middle. On the other hand, when a component is referred to as being "directly connected" or "directly coupled" to another component, it should be understood that there are no other components in the middle.

[0019] "Bipolar coordinate" refers to a two-dimensional plane coordinate system with two poles. The position can be defined by two poles and the ray connecting the two poles. Any point in the bipolar coordinate system can be determined by its distances from the two poles and the angle measured counterclockwise from one of the poles to the point. "ZR drive assembly" refers to a two-dimensional composite motion mechanism for realizing the linear motion of the Z axis and the rotational motion of the R axis, which can be an integrated or split combination.

[0020] A schematic structural diagram of an embodiment of a bipolar coordinate 3D printer of the present invention is as Figure 1 shown, including a fixed base 100, a ZR drive assembly 200, a turntable 300, a swing arm 400, and a print head assembly 500.

[0021] The ZR driving assembly 200 includes a ZR driving unit 210 and a sliding sleeve 230. The ZR driving unit 210 includes a linear driving motor 211 and a rotary driving motor 212. The output shaft of the linear driving motor 211 is a lead screw shaft 221 and is configured with a matching lead screw nut 231. The rotary driving motor 212 drives a spline shaft 222 through a synchronous belt reduction mechanism 213. The sliding sleeve 230 is a spline shaft sleeve that cooperates with the spline shaft 222. The lead screw shaft 221 is parallel to the spline shaft 222. The lead screw nut 231 is rotatably connected to the sliding sleeve 230 through a connecting member 232.

[0022] The turntable 300 includes a rotary driving assembly 310 and a rotary carrier 320. The rotary driving assembly 310 includes a turntable driving motor 311 and a synchronous belt reduction mechanism 312. The turntable driving motor 311 drives the rotary carrier 320 to rotate through the synchronous belt reduction mechanism 312. The rotary carrier 320 is provided with a carrier surface 321 for receiving printing materials. The reduction mechanism 312 can also adopt other suitable reduction mechanisms such as a harmonic reducer, a worm reducer, a planetary gear reducer, and a cycloidal pinwheel reducer.

[0023] The main function of the reduction mechanism 312 is to improve the control accuracy and the rotary torque. When the turntable driving motor 311 adopts a high-precision direct drive motor (DD motor), the reduction mechanism may not be required, and the rotary carrier 320 is directly driven by the direct drive motor.

[0024] One end of the swing arm 400 is fixedly connected to the sliding sleeve 230. The swing arm 400 can rotate horizontally with the sliding sleeve 230. The other end of the swing arm 400 is provided with a print head assembly 500. The print head assembly 500 is configured with a material extrusion port 510 for conveying printing materials to the carrier surface 321.

[0025] To ensure that the projection of the movement trajectory of the material extrusion port 510 on the horizontal plane is a continuous arc centered on the center of the carrier surface 321, the swing arm 400 can be set as a length-adjustable structure (not shown). By adjusting the length of the swing arm 400, the deviation generated during actual use can be reduced.

[0026] The print head assembly 500 can adopt a 3D print head assembly using wire or fluid materials such as fused deposition modeling (FDM), stereolithography (SLA), and paste extrusion. The supporting feeding device (not shown) is connected to the pipe joint 520 of the print head assembly 500 through a conduit for conveying printing materials to the material extrusion port 510.

[0027] The ZR drive assembly 200, the turntable 300 are connected to the fixed base 100. The ZR drive assembly 200 drives the swing arm 400 to perform vertical linear motion and horizontal rotational motion via the lead screw shaft 221, the spline shaft 222 and the sliding sleeve 230, and at the same time drives the material extrusion port 510 to perform arc motion in the horizontal direction and linear motion in the vertical direction. The projection of the motion trajectory of the material extrusion port 510 on the horizontal plane is a continuous arc with the axis of the sliding sleeve 230 as the center and passing through the center of the carrier table surface 321, and its vertical projection covers all the effective printing areas of the carrier table surface 321.

[0028] The schematic diagram of the printing principle of the bipolar coordinate 3D printer of the present invention is as Figure 2 shown. The center 10 of the carrier table surface 321 is the first pole of the bipolar coordinate, the axis 20 of the sliding sleeve 230 is the second pole of the bipolar coordinate. The swing arm 400 rotates around the axis 20 of the sliding sleeve 230. The projection of the motion trajectory 30 of the material extrusion port 510 on the horizontal plane is a continuous arc with the axis 20 of the sliding sleeve 230 as the center and passing through the center 10 of the carrier table surface 321. The horizontal rotation of the carrier table surface 321 and the rotation of the swing arm 400 can cover all the effective printing areas of the carrier table surface 321.

[0029] The schematic diagram of the structure of another embodiment of the bipolar coordinate 3D printer of the present invention is as Figure 3 shown. The bipolar coordinate 3D printer adopts a ZR drive assembly 200 with a coaxial structure. The hollow shaft 220 is used as the rotation drive shaft of the sliding sleeve 230, and the lead screw shaft 221 is used as the vertical motion drive shaft of the sliding sleeve 230. The lead screw nut 231 is coaxially arranged in the hollow shaft 220. The linear drive motor 211 drives the lead screw shaft 221, and the rotation drive motor 212 drives the hollow shaft 220 via the synchronous belt reduction mechanism 213. One end of the swing arm 400 is fixedly connected to the sliding sleeve 230, and the other end of the swing arm 400 is provided with a print head assembly 500.

[0030] In this embodiment, except for the ZR drive assembly 200, the structures of the fixed base 100, the turntable 300 and the print head assembly 500 are the same as those in the previous embodiment. The bipolar coordinate 3D printer adopting the coaxial ZR drive assembly 200 structure can further optimize the space utilization rate.

[0031] Figure 4 is the schematic diagram of the structure of the coaxial ZR drive assembly. The coaxial ZR drive assembly 200 includes a ZR drive unit 210, a hollow shaft 220, a lead screw shaft 221 and a sliding sleeve 230.

[0032] The lead screw shaft 221 is coaxially arranged inside the hollow shaft 220. The hollow shaft 220 is provided with an axially penetrating opening guiding chute 223. The sliding sleeve 230 is provided with a lead screw nut 231 meshing with the lead screw shaft 221. The lead screw nut 231 is accommodated inside the hollow shaft 220. A guiding slider 232 protruding from the opening guiding chute 223 is provided on the lead screw nut 231. The sliding sleeve 230 can rotate with the hollow shaft 220 and can also perform a linear motion with the lead screw nut 231.

[0033] The ZR driving unit 210 includes a linear driving motor 211 and a rotary driving motor 212. The lead screw shaft 221 is directly driven by the linear driving motor 211 to perform a rotary motion. The hollow shaft 220 is driven by the rotary driving motor 212 through a synchronous belt reduction mechanism 213 to perform a rotary motion. Other suitable reduction mechanisms such as a harmonic reducer, a worm reducer, a planetary gear reducer, and a cycloidal pinwheel reducer can also be used for the reduction mechanism 213. When the rotary driving motor uses a high-precision direct drive motor (DD motor), the reduction mechanism may not be required, and the hollow shaft 220 is directly driven by the direct drive motor.

[0034] In the bipolar coordinate 3D printer of the present invention, the linear driving motor 211, the rotary driving motor 212, and the turntable driving motor 311 are all in fixed positions during the printing process, which can ensure the stability of the printing process.

[0035] The control method flow of the bipolar coordinate 3D printer of the present invention is as Figure 5 , and includes a calculation step S1 and a control step S2.

[0036] In the calculation step S1, the turntable rotation angle, the swing arm movement trajectory, and the print head extrusion amount are calculated according to the model data.

[0037] In the control step S2, according to the calculation results of the calculation step, the ZR driving assembly and the turntable movement are coordinately controlled to print the material extrusion port along a preset trajectory.

[0038] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A bipolar coordinate 3D printer, comprising a fixed seat, a turntable, a ZR drive assembly, a swing arm and a print head assembly, characterized in that: The turntable and the ZR drive assembly are mechanically connected to the fixed seat; the turntable at least includes a rotation drive assembly and a rotating platform, the rotation drive assembly drives the rotating platform to rotate, and the rotating platform is provided with a platform surface for receiving printing materials; the ZR drive assembly at least includes a ZR drive unit and a sleeve, and the ZR drive unit is configured to drive the sleeve to perform vertical linear motion and horizontal rotational motion; one end of the swing arm is fixedly connected to the sleeve, and the length direction of the swing arm is configured to be able to rotate in the horizontal direction with the sleeve; the print head assembly is arranged at the other end of the swing arm, and the print head assembly is provided with at least one material extrusion port for conveying printing materials to the platform surface; the material extrusion port performs arc motion in the horizontal direction and linear motion in the vertical direction with the swing arm, and the projection of the motion trajectory of the material extrusion port on the horizontal plane is a continuous arc with the axis of the sleeve as the center and passing through the center of the platform surface.

2. A bipolar coordinate 3D printer according to claim 1, characterized in that: The ZR drive unit includes a rotary drive motor and a linear drive motor. The output shaft of the linear drive motor is a screw shaft and is provided with a matching screw nut. The rotary drive motor is configured to drive a spline shaft. The sleeve is configured to be a spline sleeve that cooperates with the spline shaft. The screw shaft is arranged parallel to the spline shaft. The screw nut is rotationally connected to the sleeve via a connecting piece.

3. A bipolar coordinate 3D printer according to claim 1, characterized in that: The ZR drive unit includes a rotary drive motor and a linear drive motor, the output shaft of the linear drive motor is a screw shaft and is provided with a matching screw nut, the rotary drive motor is configured to drive the hollow shaft; the sliding sleeve is configured to be a sliding sleeve that cooperates with the hollow shaft, and the hollow shaft is provided with an axially penetrating open linear groove; the screw shaft is coaxially arranged in the hollow shaft, and the screw nut is accommodated in the hollow shaft and fixedly connected to the sliding sleeve via a connecting piece arranged in the open linear groove.

4. A bipolar coordinate 3D printer according to claim 1, characterized in that: The rotary drive assembly includes a speed reduction mechanism.

5. A bipolar coordinate 3D printer according to claim 1, characterized in that: The length of the swing arm is adjustable.

6. A control method for a bipolar coordinate 3D printer according to claim 1, characterized in that Includes steps: a) Calculate the turntable rotation angle, swing arm motion trajectory and print head extrusion amount based on the model data; b) Coordinated control of the ZR drive assembly and the turntable movement to allow the material extrusion outlet to print along the preset trajectory.

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