Material table rotation control method, 3D printing method and 3D printing device

Abstract

The invention discloses a material table rotation control method, a 3D printing method and a 3D printing device.The material table rotation control method comprises the following steps that a printing head, a material table, a controller, a first driving mechanism and a second driving mechanism are provided, the printing head comprises a printing base and a nozzle base, the nozzle base is rotatably arranged on the printing base, and the first driving mechanism is driven by the controller; at least one extrusion opening is formed in the bottom of the nozzle seat; a three-dimensional model to be printed is sliced to generate a rotation instruction of the printing head, and in the printing process, the controller controls the first driving mechanism to drive the nozzle seat to drive the at least one extrusion opening to rotate together according to the rotation instruction of the printing head. According to a rotation instruction of the printing head, the controller controls the second driving mechanism to drive the material table frame to rotate along with the nozzle seat, so that the angle difference between the material table and the printing head is smaller than or equal to a preset value. According to the invention, excessive winding of flexible lines such as a feeding pipe and / or a wire due to rotation of the printing head is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and particularly to a method for controlling the rotation of a material platform, a 3D printing method, and a 3D printing device. Background Art

[0002] 3D printing is based on a digital model file and constructs an object by layer-by-layer printing. Among them, the fused deposition modeling process, namely FFF (Fused Filament Fabrication) or FDM method, extrudes a flowable printing material through a nozzle moving along a printing path and stacks the layers to form a three-dimensional model. According to the layer pattern information of the digital model file, the relative movement between the nozzle and the platform in the XY plane enables the nozzle to reach any position within a certain area above the platform. While the nozzle moves above the platform, it also extrudes the printing material at an appropriate speed until a layer of printing is completed. After a layer of printing is completed, the print head and the printing platform move away from each other by a certain distance, such as the layer thickness, and then continue to print a new layer. The layers are stacked until a three-dimensional entity is formed. The printing material is generally a fusible thermoplastic material, construction slurry, food slurry, or biological slurry, etc. Generally, construction slurry or biomedical slurry may not need to be heated. In the traditional fused deposition 3D printing method, it is generally difficult to achieve simultaneous printing and extrusion forming with multiple nozzles. A 3D printer with multiple nozzles, such as two nozzles, generally extrudes the printing material alternately with the nozzles. Although the rotation of multiple nozzles of the print head can achieve simultaneous printing with multiple nozzles, the rotation angle of multiple nozzles is often restricted by the kinking effect of the wire feeding tube or wire harness for the filament. The control process of multiple nozzles is additionally restricted by the physical structure of the printer, which affects the flexibility, printing speed, and printing accuracy of the printing process, and also increases the development difficulty of the control system. Summary of the Invention

[0003] Aiming at the deficiencies existing in the above-mentioned prior art, the present invention provides a method for controlling the rotation of a material platform, a 3D printing method, and a 3D printing device, which solves the technical problem that in the prior art, when a 3D printing device is provided with multiple nozzles, the rotation angle of the multiple nozzles is often restricted by the kinking effect of the wire feeding tube or wire harness for the filament.

[0004] In a first aspect, the present invention discloses a method for controlling the rotation of a material platform, providing a print head, a material platform, a controller, a first driving mechanism and a second driving mechanism. The print head includes a print base and a nozzle base. The nozzle base is rotatably arranged on the print base. At least one extrusion port is arranged at the bottom of the nozzle base, and at least one of the extrusion ports is used for extruding printing material. The material platform includes a material platform frame, a base frame and at least one feeding component. The material platform frame can rotate relative to the base frame. The feeding component is arranged on the material platform frame and rotates together with the material platform frame. The feeding component is used for conveying printing material to at least one of the extrusion ports. The first driving mechanism is used for driving the nozzle base to rotate. The second driving mechanism is used for driving the material platform frame to rotate. The controller is used for controlling the first driving mechanism and the second driving mechanism. A flexible circuit is connected between the material platform frame of the material platform and the nozzle base of the print head. The flexible circuit includes a printing material transmission circuit formed between the feeding component and at least one of the extrusion ports for transmitting printing material. The material platform frame of the material platform follows the rotation of the nozzle base of the print head to prevent or reduce the winding of the flexible circuit.

[0005] The method includes the following steps: The three-dimensional model to be printed is subjected to slicing processing to generate a rotation instruction for the print head (rotation of the nozzle base of the print head). During the printing process, the controller controls the first driving mechanism to drive the nozzle base to rotate according to the rotation instruction of the print head, and controls the second driving mechanism to drive the material platform frame to follow the nozzle base to rotate according to the rotation instruction of the print head, so that the angle difference between the material platform and the print head is less than or equal to a preset value. Or, the three-dimensional model to be printed is subjected to slicing processing to generate a rotation instruction for the print head (rotation of the nozzle base of the print head) and a rotation instruction for the material platform. During the printing process, the controller controls the first driving mechanism to drive the nozzle base to rotate according to the rotation instruction of the print head, and controls the second driving mechanism to drive the material platform frame to follow the nozzle base to rotate according to the rotation instruction of the material platform, so that the angle difference between the material platform and the print head is less than or equal to a preset value.

[0006] When generating the instruction for the rotation of the print head, an instruction for the rotation of the material platform is also generated. Or, before printing the printing model or a partial printing layer, an instruction for the rotation of the material platform is generated according to the rotation instruction of the print head. During the printing process, the machine instruction for the rotation of the print head is transmitted to the first driver, and at the same time, the machine instruction for the rotation of the material platform is transmitted to the second driver.

[0007] The improvement of the method for controlling the rotation of the material platform of the present invention lies in that during the printing process, the print head moves along a preset printing path, and the nozzle base of the print head rotates a preset rotation angle. However, the rotation process may be fast or slow, and may even occasionally rotate in the reverse direction. The material platform frame of the material platform rotates the preset rotation angle in one direction (preset rotation angle direction) or rotates the preset rotation angle at a uniform speed along the preset rotation angle direction within the time taken for the print head to complete the preset path, with an error not greater than ±40%.

[0008] The further improvement of the material platform rotation control method of the present invention lies in that during the printing of the closed contour printing path in the printing layer of the three-dimensional model, the print head moves one week along the closed contour printing path, the nozzle seat of the print head rotates one week, and the material platform frame of the material platform rotates one week in one direction or rotates uniformly for one week, with an error not greater than ±40%.

[0009] Specifically, during the printing of the contour of one layer, the print head (the nozzle seat of the print head) may rotate one week. As Figure 7 shown, during the movement of the print seat 72 of the print head, the nozzle seat 71 rotates, as shown by the arrow θ. When printing the printing path 90 of the contour, after the print head moves one week along the printing path 90, the nozzle seat 71 may rotate one week along the arrow θ, but the rotation process may be sometimes fast and sometimes slow, and may even occasionally rotate in the reverse direction. The material platform (the material platform frame of the material platform) can maintain a one-way rotation or a uniform rotation in the same overall rotation direction as the print head during the time when the print head rotates one complete week and rotate approximately one complete week. That is, during the printing of the closed layer contour printing path of the three-dimensional model, the print head moves one week along the closed layer contour printing path, and at the same time, the nozzle seat of the print head also rotates one week. During this process, the material platform can follow the print head and rotate one week in one direction or rotate uniformly for one week.

[0010] During the printing of the contour of one layer, the print head (the nozzle seat of the print head) may rotate several weeks. As Figure 8 shown, during the movement of the print seat 72 of the print head, the nozzle seat 71 rotates, as shown by the arrow θ. When moving along the printing path 90, after the print head moves several weeks along the printing path 90, the nozzle seat 71 may rotate several weeks along the arrow θ, but the rotation process may be sometimes fast and sometimes slow, and may even occasionally rotate in the reverse direction. The material platform (the material platform frame of the material platform) can maintain a one-way rotation or a uniform rotation in the same overall rotation direction as the print head during the time when the print head rotates several complete weeks and complete approximately several corresponding weeks of rotation.

[0011] The further improvement of the material platform rotation control method of the present invention lies in that when the angle difference between the material platform and the print head increases, the rotation of the material platform is started or the rotation of the material platform is accelerated; when the angle difference between the material platform and the print head decreases, the rotation of the material platform is stopped or the rotation of the material platform is slowed down; or,

[0012] when the angular velocity and angular acceleration of the print head are respectively less than the preset values, the material platform rotates synchronously with the print head; or,

[0013] When the angular velocity or angular acceleration of the material platform exceeds the preset value due to its synchronous rotation following the rotation of the print head, if the rotation direction of the print head is the first direction (e.g., one of clockwise or counterclockwise), the material platform rotates in advance in the first direction with a longer rotation time to reduce its angular velocity or angular acceleration; or when the print head has completed a preset rotation angle but the material platform has not, the material platform continues to rotate in the first direction until it completes the preset rotation angle, using a longer rotation time to reduce its angular velocity or angular acceleration.

[0014] The rotation of the print head refers to the rotation of the nozzle seat of the print head relative to the print base; the rotation of the material platform can refer to the rotation of the material platform frame, such as the rotation relative to the base frame.

[0015] The improvement of the material platform rotation control method of the present invention lies in adopting a threshold control method: taking the absolute value of the angle difference between the material platform frame of the material platform and the nozzle seat of the print head as the control target. When the absolute value of the angle difference is greater than or equal to the first preset value, the material platform starts to rotate to reduce the absolute value of the angle difference. When the absolute value of the angle difference is less than the second preset value, the material platform stops rotating, and the second preset value is less than or equal to the first preset value; or,

[0016] Adopting a feedback control method: detecting the angle difference d between the material platform frame of the material platform and the nozzle seat of the print head, and using d×C as the driving rotation signal of the material platform, where C is a constant or C increases as the absolute value of d increases and decreases as the absolute value of d decreases; or,

[0017] Adopting a predictive control method: predicting the rotation of the print head. Since the rotation of the print head is preset and known in advance, according to the rotation instruction sequence of the print head, the material platform frame of the material platform rotates in advance relative to the nozzle seat of the print head; for example, when a series of nozzle seat rotation control instructions, such as sequence n, n + 1, n + 2... etc., when the nozzle seat is to rotate clockwise by a certain angle currently or in the future t time, the material platform can rotate clockwise before the current step and can rotate at a lower speed; the advantage of this is that it can further reduce the acceleration and angular velocity during the rotation of the material platform (whether it is the average angular velocity or the maximum angular velocity)! In this way, the minimum angular acceleration and / or angular velocity of the material platform frame rotation can be achieved; or,

[0018] Adopt on-site command control method: The three-dimensional model to be printed is sliced to generate the rotation command of the print head. Before printing the model or a partial printing layer, the rotation command of the material platform is generated according to the rotation command of the print head. During the printing process, according to the rotation command of the print head, the first driver is controlled to drive the nozzle seat of the print head to rotate, and according to the rotation command of the material platform, the second driver is controlled to drive the material platform frame of the material platform to rotate.

[0019] Specifically, when adopting the threshold control method, the angle difference between the material platform frame of the material platform and the nozzle seat of the print head is used as the control target to control the material platform to follow the print head to rotate. When the absolute value of the angle difference between the material platform and the nozzle seat is greater than the start threshold K, the material platform starts to follow and rotate, and the rotation direction of the material platform is determined according to the sign (positive or negative) of the angle difference, so that this absolute value decreases. When the rotation of the print head makes this absolute value decrease, the material platform does not need to rotate. Only when the rotation of the print head makes this absolute value greater than the preset value does the material platform follow and rotate. When the angle difference between the material platform and the nozzle seat is less than the stop threshold T, the material platform stops following and rotating. Preferably, the stop threshold T is less than or equal to the start threshold K. The start threshold K can be 0. For example, when the rotation angular velocity of the nozzle seat is less than the threshold R1, the start threshold K can be 0, that is, the material platform completely follows the nozzle seat to rotate.

[0020] The greater the lagging angular difference between the material platform frame and the nozzle seat, the greater the rotation speed of the material platform frame; the longer the duration of the lagging angular difference between the material platform frame and the nozzle seat, the greater the rotation speed of the material platform frame; the direction of change of the lagging angular difference between the material platform frame and the nozzle seat is increasing, the greater the rotation speed of the material platform frame.

[0021] The improvement of the material platform rotation control method of the present invention further lies in that according to the sequence of rotation angles in the print head control instruction (such as G code), the sequence of rotation angles in the rotation command of the print head is equalized to obtain the rotation angle P. Some small and frequent forward and reverse rotations may be cancelled out. When the rotation angle P is greater than or equal to the first preset value, the material platform rotates. When the rotation angle P is less than the second preset value, the material platform does not rotate. The first preset value is greater than or equal to the second preset value; or,

[0022] The sequence of rotation angles in the rotation command of the print head is equalized to obtain the rotation angle P. During the time span of this sequence, the material platform follows the print head to rotate this rotation angle P unidirectionally or uniformly, and the error is not greater than ±40%. The rotation direction of the material platform is judged according to the sign of the rotation angle P.

[0023] The further improvement of the material platform rotation control method of the present invention lies in that within the preset printing process time range or the preset printing path distance, if the comprehensive rotation result of the nozzle seat is towards the preset direction, the material platform frame can rotate uniformly towards the preset direction. At the end of the preset printing process time range or the preset printing path distance, the material platform frame rotates by a preset angle, and the preset angle is equal to the comprehensive rotation angle of the nozzle seat within the preset printing process time range or the preset printing path distance, with an error not greater than ±40%.

[0024] For the next preset printing process time range or preset printing path distance, repeat the above process.

[0025] Too fast rotation of the material platform or rotation with too large an acceleration is likely to cause the swing or vibration of feeding equipment such as the feeding tray on the material platform, and is also likely to cause the vibration of the entire equipment, affecting the printing accuracy, operation stability and reliability of the equipment, and may also affect the printing speed.

[0026] The further improvement of the material platform rotation control method of the present invention lies in that the rotation instruction of the print head and / or the rotation instruction of the material platform adopt a numerical control programming language such as G-code (English name G-code), also known as RS-274 or G instruction, or adopt other instructions that can be executed by a chip (such as a CPU); and / or,

[0027] The controller controls the first driver and the second driver with electrical pulses. The electrical pulses can be voltage pulses or current pulses. For example, a pulse width modulation PWM (Pulse Width Modulation) signal is used to control a switching tube, such as a MOSFET tube (Metal-Oxide-Semiconductor Field-Effect Transistor), to control the driving of a stepper motor or a permanent magnet synchronous motor to rotate, etc. The first driving mechanism and the second driving mechanism can use a stepper motor or a permanent magnet synchronous motor to drive the print head or the material platform to rotate, for example, through a synchronous belt or a gear pair, etc.

[0028] In a second aspect, the present invention also provides a 3D printing method, including the following steps:

[0029] S1: When starting to print or before starting, first detect the angle difference between the material platform and the print head, and adjust the angle difference to be less than or equal to an initial preset value (the initial preset value can be 0);

[0030] S2: Start the printing process, and use the material platform rotation control method described above to control the material platform to rotate following the print head.

[0031] In a third aspect, the present invention further provides a 3D printing device, which adopts the material table rotation control method or the 3D printing method as described above. At least two extrusion outlets are provided at the bottom of the nozzle seat, and at least two of the extrusion outlets are respectively used for extruding printing materials; wherein,

[0032] At least two feeding drives are provided on the material table frame. The two feeding drives are arranged on the material table frame and can rotate together with the material table frame. The two feeding drives are used to respectively convey filamentous printing materials to at least two of the extrusion outlets; the directions of the discharge ports of the filamentous printing materials respectively conveyed by the two feeding drives are inclined downward and close to each other, or the discharge ports of the two feeding drives are inclined downward in the direction close to the rotation axis of the material table frame;

[0033] Or,

[0034] A first material tray, a first feeder, a second material tray and a second feeder are provided on the material table frame. The first material tray, the first feeder, the second material tray and the second feeder are arranged in sequence around the rotation axis of the material table frame in a circumferential manner. The drive motor of the first feeder is arranged in a direction away from the rotation axis of the material table frame relative to the first feeder, and the drive motor of the second feeder is arranged in a direction away from the rotation axis of the material table frame relative to the second feeder.

[0035] Compared with the prior art, the effects of the present invention are positive and obvious. The specific technical effects are as follows:

[0036] 1. Avoid the excessive winding of flexible lines such as feeding pipes and / or wires due to the rotation of the print head, which is beneficial to the transmission of printing materials, and also makes the rotation of the print head (the rotation of the nozzle seat) more free and the nozzle (or extrusion outlet) can move more freely along the printing path, realizing a more flexible and free forming process.

[0037] 2. The angular difference between the material table and the print head at each time can be predicted through the rotation instruction of the print head, and the overall optimization control process can be carried out. The rotation of the material table can be controlled in a more accurate, more stable, with less fluctuation in the rotation speed of the material table and more energy-saving manner.

[0038] 3. Greatly reduce the calculation or signal processing process for controlling the rotation of the material table during the printing process, that is, it can reduce the occupation of the computing resources of the controller, and also reduce the communication volume between the controller and sensors or other computers or networks, improve the stability of the system and is also beneficial to reducing costs. Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0040] Figure 1 It is a schematic diagram of a 3D printing system with a rotatable material platform.

[0041] Figure 2 It is a schematic diagram of another 3D printing system with a rotatable material platform.

[0042] Figure 3 It is a three-dimensional schematic diagram of a 3D printing system with a rotatable material platform.

[0043] Figure 4 It is a schematic diagram of a 3D printing system in which a driving scheme of a rotating material platform and two feeding drives are arranged at an angle to each other.

[0044] Figure 5 It is a schematic diagram of an embodiment of a 3D printing system in which the central axis of a material platform is fixedly connected to a base frame or two feeding drives are arranged at an angle to each other.

[0045] Figure 6 It is a schematic diagram of an embodiment of an arrangement mode in which a feeder and a material tray on a material platform are arranged circumferentially around the rotation axis of the material platform frame.

[0046] Figure 7 It is a schematic diagram of the process of the print head printing while rotating along the printing path of the closed contour in the printing layer.

[0047] Figure 8 It is a schematic diagram of the process of the print head printing while rotating along a circular or spiral path.

[0048] Figure 9 It is a schematic diagram of the flow of a printing method.

[0049] Figure 10 It is a schematic diagram of the flow of another printing method. Detailed implementation manners

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0051] Figures 1 to 3Schematically shows a 3D printing system, including a print head, a base frame 11, and a material platform; wherein: The print head includes a print base 72 and a nozzle base 71. The nozzle base 71 is disposed on the print base 72. The nozzle base 71 can rotate relative to the print base 72 about a first axis (such as the axis of the nozzle base 71 itself), as shown by the arrow θ in the figure for the rotation direction. The nozzle base 71 is provided with an extrusion port 73 on one side facing the first end of the first axis (usually downward, but can also be facing other directions). The number of extrusion ports 73 can be one or multiple. The extrusion port 73 is used to extrude printing material. The material platform includes a material platform frame 20 and at least one feeding component. The material platform frame 20 is disposed on the base frame 11. The material platform frame 20 can rotate relative to the base frame 11 about a second axis (such as the axis of the material platform frame 20 itself), for example, as shown by the arrow Φ in the figure for the rotation direction. The feeding component is disposed on the material platform frame 20 and can rotate with the material platform frame 20. The feeding component is used to convey printing material to the extrusion port 73; A flexible circuit is connected between the material platform frame 20 and the nozzle base 71. The flexible circuit includes a printing material conveying circuit (the printing material conveying route can be a feeding pipe 37 or, when the printing material is filament printing material (filament), can be the continuous filament itself, etc.) formed between the feeding component and the extrusion port 73; The material platform frame 20 can rotate following the nozzle base 71 to prevent excessive winding of the flexible circuit.

[0052] The 3D printing system may include two rotation driving mechanisms, which are respectively used to drive the rotation of the material platform frame 20 and the nozzle base 71. The rotation driving mechanism for driving the material platform frame 20 can be, for example, Figure 1 or Figure 3 as shown, the first motor 61 drives the rotation of the material platform frame 20 through a synchronous belt 66 or, as Figure 2 shown, drives the rotation of the material platform frame 20 through a gear pair. Similarly, it can be, for example, Figure 4 shown, the central wheel of the linear angle coupling transmission mechanism is coaxially fixedly connected or transmission-connected to the material platform frame 20 to drive the rotation of the material platform frame 20; The rotation driving mechanism for driving the nozzle base 71 can be, for example, Figure 1 shown, the second motor 62 fixedly connected to the print base 72 drives the rotation of the nozzle base 71 through a synchronous belt, or the second motor 62 drives the rotation of the nozzle base 71 through a gear pair. It can also adopt, for example, Figure 3 shown, the central wheel of the linear angle coupling transmission mechanism is coaxially fixedly connected or transmission-connected to the nozzle base 71 to drive the rotation of the nozzle base 71. It is also possible to coaxially fixedly connect the rotor of a hollow rotor motor to the nozzle base 71 to drive the rotation of the nozzle base 71.

[0053] During the printing process, the print base 72 moves along a preset printing path 90, which can be referred to Figure 3 , Figure 7 and Figure 8 , and at the same time, the nozzle base 71 rotates relative to the print base 72. As shown in the figure, the nozzle base 71 rotates along the arrow θ. For example,Figure 7 In this case, when the print head moves from position A to position B, in order to make both the extrusion port 73 and the auxiliary extrusion port 74 located on the printing path 90 (or located on their respective printing paths), the nozzle seat 71 rotates accordingly. That is, during the process of the print head moving from position A along the printing path 90 to position B, the nozzle seat 71 rotates relative to the print base 72, so that both the extrusion port 73 and the auxiliary extrusion port 74 can be kept on the preset printing path, such as the printing path 90, to realize the simultaneous printing process of multiple nozzles. If the auxiliary extrusion port 74 extrudes the continuous fiber printing material and the extrusion port 73 extrudes the resin material, then when the auxiliary extrusion port 74 extrudes the continuous fiber printing material onto the printing platform, the resin material extruded by the extrusion port 73 can cover and combine with the continuous fiber printing material extruded onto the printing platform to form a composite material model. Figure 7 In this case, it shows the closed contour printing path 90 in a certain printing layer of the printing model. During the printing process along the printing path 90, the print base 72 of the print head moves one week along the printing path 90, and at the same time, the nozzle seat 71 also rotates one week relative to the print base 72. The printing layer may include multiple closed contour printing paths. Figure 8 In this case, it shows that the printing path 90 can be a spiral ring, or a closed pattern or an irregular ring, that is, during the continuous printing process of the print head along the Figure 8 printing path 90 in this case, the print base 72 moves along the printing path 90, and at the same time, the nozzle seat 71 rotates relative to the print base 72. For example, when the print base 72 moves a preset number of turns along the printing path 90, the nozzle seat 71 may also rotate a corresponding number of turns relative to the print base 72. During the printing process, the material table frame 20 drives the feeding component to rotate along with the nozzle seat 71, so that the kinking or winding of the flexible circuit between the material table frame 20 and the nozzle seat 71 can be controlled, and this kinking or winding can be reduced or eliminated. The feeding component conveys the printing material to the extrusion port 73 on the print head, and the printing material extruded by the extrusion port 73 on the print head can be deposited on a printing platform 92. After completing one layer of printing, the distance between the extrusion port 73 and the printing platform 92 is increased, for example, the distance of one layer of printing layer thickness is increased, and then the print head performs the printing of the next layer, and thus layer by layer stacking forms the printing model 40. For example, the extrusion port 74 can extrude the continuous fiber material, and the extrusion port 73 can extrude the molten plastic material. For example, when the extrusion port 74 extrudes the continuous fiber onto the printing platform (on the printing platform or on the printing model 40 on the printing platform), the subsequent molten plastic extruded by the extrusion port 73 covers and combines with the continuous fiber material, so that the printing of the composite material model can be formed. Since the material table frame 20 drives the feeding component to rotate along with the nozzle seat 71, the excessive winding of flexible circuits such as the feed pipe 37 and the wire 52 is avoided. In short, that is, the excessive winding of the feed pipe 37 and / or the wire 52 and the like due to the rotation of the nozzle seat 71 on the print head is avoided, the feeding is smoother, and the rotation angle of the nozzle seat 71 can be freely unrestricted, and the forming process can be more free and flexible.

[0054] The flexible circuit connecting the material table frame 20 of the material table and the nozzle seat 71 of the print head may further include filamentous printing material, a feed pipe 37, a conducting wire 52, an air supply pipe 44, an ink supply pipe, etc.

[0055] Figure 1 Among them, the flexible circuit between the material table and the print head further includes a conducting wire 52. The conducting wire 52 can be connected to electrical appliances on the print head, such as a heating block 75 or a sensor of the second rotation induction device 53, etc. A nozzle holder 712 can also be arranged on the nozzle seat 71. The extrusion port 73, the heating block 75 or the sensor of the second rotation induction device 53, etc. are first connected to the nozzle holder 712, and then connected to the nozzle seat 71 through the nozzle holder 712. In this way, it is more convenient to connect various devices to the nozzle seat 71. For example Figure 2 the multiple extrusion ports, the extruder 45, the inkjet head 41, etc. in can all be first connected to the nozzle holder 712, and then connected to the nozzle seat 71 through the nozzle holder 712. Figure 1 In the figure, it is shown that the feeding component on the material table frame 20 is a material tray 31, and filamentous printing material is wound on the material tray 31, such as filamentous resin material printing material. The feeding component may further include a feeder 35. The feeder 35 can also be arranged on the material table frame. The feeder 35 is a device that feeds and drives the filamentous printing material along the axial direction of the printing material. The feeder 35 is connected to the nozzle seat 71 through a feed pipe 37, and conveys the driven filamentous printing material to the extrusion port 73 along the feed pipe 37. A conductive slip ring 51 can also be arranged on the material table, such as Figure 1 、 Figure 3 and Figure 5 shown, the conductive slip ring 51 includes a first slip ring 511 and a second slip ring 512 that can rotate relative to each other, and a plurality of conductive circuits can be kept conducting during the relative rotation between the first slip ring 511 and the second slip ring 512. For example, the first slip ring 511 of the conductive slip ring 51 is connected to the material table frame 20, such as fixedly connected (fixed connection), and the second slip ring 512 is connected to the base frame. For example, the second slip ring 512 is connected to Figure 5is fixedly connected to the central axis 10. The wire 52 connected to the first slip ring 511 on the conductive slip ring 51 can be used to connect to electrical appliances or detection devices on the material platform 20 or the nozzle base 71, such as feeders 35 and 36, heating blocks, temperature sensors, or sensors of the second rotation induction device 53, etc. The wire 52 connected to the second slip ring 512 can be connected to the controller 54. Control instructions for driving the rotation of the material platform 20 and the nozzle base 71 can run in the controller 54, and it can also control or detect electrical appliances on the material platform or the print head or collect sensor signals on the material platform or the print head. The controller 54 can be a control device or a control system formed by multiple control devices connected by wires or wirelessly. For example, a main controller connects two slave controllers through a bus, and the two slave controllers respectively control the rotation drive mechanisms of the nozzle base 71 and the material platform 20. A through hole can also be axially provided in the conductive slip ring 51 for air supply. The conductive slip ring 51 can also be arranged on the print head, such as Figure 2 shown. For example, the first slip ring 511 of the conductive slip ring 51 is fixedly connected to the nozzle base 71, and the second slip ring 512 is fixedly connected to the print base 72.

[0056] In addition, the following electrical appliances can also be provided on the nozzle base 71 of the print head, such as a photosensitive curing light source. Through the rotation of the nozzle base 71 relative to the print base 72, along the movement direction of the print head, the photosensitive curing light source is located behind the extrusion port 73 and is used to cure the printing material extruded from the extrusion port 73; and / or a pre-heater. Through the rotation of the nozzle base 71 relative to the print base 72, along the movement direction of the print head, the pre-heater is used to apply heat in front of the extrusion port 73 to heat the area where the print head is about to print and / or to heat the printing material just extruded from the extrusion port 73; and / or a temperature measurer. Through the rotation of the nozzle base 71 relative to the print base 72, along the movement direction of the print head, the temperature measurement area of the temperature measurer is in front of the extrusion port 73 to measure the temperature of the area where the print head is about to print; and / or a detector. Through the rotation of the nozzle base 71 relative to the print base 72, along the movement direction of the print head, the detector acts behind the extrusion port 73 to detect the quality of the printing material extruded from the extrusion port 73; and / or a cooling fan. Along the movement direction of the print head, the cooling fan is located behind the extrusion port 73 and is used to blow air towards the printing material just extruded from the extrusion port 73; and / or an inkjet head 41, such as Figure 2As shown, by the rotation of the nozzle seat 71 relative to the printing seat 72, along the moving direction of the print head, the inkjet head is located behind the extrusion port 73, and is used to inkjet the printing material extruded from the extrusion port 73 according to a preset pattern, and / or, an extruder 45, which can be used to pressurize and extrude granular printing material, for example, heat and pressurize and extrude granular resin printing material through a screw extruder, and form an extrusion port at the lower end of the extruder 45, and / or, an air outlet 431, and the gas sent by the air supply pipe 44 is blown by the air outlet 431 to the just-extruded printing material, and / or, multiple extrusion ports are provided, such as the extrusion port 73 and the secondary extrusion port 74. The 3D printing system may further include a printing platform, the print head and the printing platform move relative to each other, the extrusion port 73 extrudes the printing material along a preset printing path, and printing is performed on the printing platform. The extrusion port can be vertically downward or inclined, such as Figure 1 As shown, by the rotation of the nozzle seat 71, it is possible to keep the extrusion port 73 tilted backward in the moving direction of the print head during the printing process, which is beneficial to the extrusion of the printing material and the formation of the printed model 40. The extrusion port can also be of various shapes, such as circular, rectangular, triangular or other polygons, or elliptical. By driving the extrusion port to rotate through the rotation of the nozzle seat 71, the shape or width dimension of the extruded printing material can be adjusted, etc.

[0057] The following devices can also be provided on the material table frame 20. Multiple trays can be provided, such as Figure 2 and Figure 3 As shown, such as the tray 31 and the secondary tray 32, which supply printing material to the extrusion port 73 and the secondary extrusion port 74 respectively. A feeder 35 and a secondary feeder 36 can also be provided to convey the printing material in the tray 31 and the secondary tray 32 to the extrusion port 73 and the secondary extrusion port 74 respectively; and / or, a blower 43, which sends air to the air outlet 431 through the air supply pipe 43; and / or, a feeding device 46, which feeds granular printing material to the extruder 45 through a feeding pipe 37; and / or, an ink cartridge 42, and the ink cartridge 42 is connected to the inkjet head 41 through an ink supply pipe to supply ink to the inkjet head 41, and the ink cartridge 42 is used to store ink.

[0058] The 3D printing system may further include: a first rotation sensing device 55, such as Figure 2 As shown, the first rotation sensing device 55 includes a correspondingly arranged sensor and an induction component. The sensor and the induction component are respectively connected to the material table frame 20 and the base frame 11. The sensor is electrically connected to the controller through a conductive slip ring 51, or the sensor and the induction component are respectively connected to the base frame 11 and the material table frame 20, and are used to detect the initial position of the rotation angle or rotation direction of the material table frame 20 relative to the base frame; and / or, a second rotation sensing device 53, such as Figure 1As shown, the second rotation induction device 53 includes a correspondingly arranged sensor and induction component. The sensor and the induction component are respectively connected to the nozzle seat 71 and the printing seat 72 of the print head. The sensor is electrically connected to the controller through a conductive slip ring 51, and is used to detect the initial position of the rotation angle or rotation direction of the nozzle seat 71 relative to the printing seat 72.

[0059] By Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, through holes 109 can be provided on the material table frame 20 or the central shaft 10 for wires 52, feeding pipes 37 or other pipelines to pass through, and a conductive slip ring 51 can also be provided.

[0060] Figure 2 , Figure 4 and Figure 5 As shown in Figure 2 the base frame 11 on the material table also includes a central shaft 10, and the central shaft 10 is fixedly connected to the base frame 11. Figure 2 As shown in Figure 4 the central shaft 10 is locked to the base frame 11 through a nut 63, a bearing 65 is sleeved on the central shaft 10, and the material table frame 20 is sleeved on the bearing 65. Figure 3 As shown in Figure 3 a gear can be provided on the material table frame 20 to form a gear pair with the gear driven by the motor 61, and the material table frame is driven to rotate by the motor 61. Figure 3 As shown in Figure 4 a central wheel 81 is provided on the material table frame 20, and the central wheel 81 is rotatably sleeved on the central shaft 10. Of course, the central wheel 81 can also be directly rotatably provided on the base frame 11, and the material table frame is driven to rotate through a linear-angle coupling transmission mechanism. Figure 4As shown, the first motor 61 drives the upper left synchronous pulley 83 to rotate, driving the left synchronous belt 67 to move circumferentially. The second motor 62 drives the upper right synchronous pulley 85 to rotate, driving the right synchronous belt 68 to move circumferentially. Thus, by controlling the first motor 61 and the second motor 62, the rotation of the central wheel 81 can be controlled. Figure 5 It is schematically shown that the central wheel 81 disposed in the fixed ring 23 is driven to rotate by the motor 61 through the synchronous belt 66, thereby driving the material table frame 20 to rotate. The motor 61 can be fixedly connected to the base frame 11. Figure 5 It is also schematically shown that the fixed ring 23 can be sleeved above the outer ring of the bearing 65 and fixedly connected to the material table frame 20 sleeved below the outer ring of the bearing 65, for example, locked together by the fastener 64. The inner ring of the bearing 65 is fixedly connected to the central shaft 10. Figure 5 It is also schematically shown that a groove 111 can be provided on the base frame 10 for accommodating the wire 52 or pipelines, etc. The groove 111 communicates with the through hole 109 on the central shaft 10.

[0061] Figure 5 It is also schematically shown that a material table bin 39 can be provided. The material table bin 39 can enclose the material trays 31 and 32 within the material table bin 39, which is beneficial for keeping the printing materials on the material trays 31 and 32 free from moisture or dust contamination. A material table bin through hole 391 is provided at the lower position of the material table bin 39 to allow the feeding pipe 37 and the wire 52, etc. to be connected from the material table frame 20 to the nozzle seat 71 on the print head. Preferably, the rotation axis of the material table frame 20 passes through the through hole 391 of the material table bin 39. Figure 4 and Figure 5 It is schematically shown that the feeders 35 and 36 are provided on the material table frame 20, and the material trays 31 and 32 can also be provided on the material table frame 20. Figure 4 The material tray 32 is omitted in the figure for the sake of display convenience. The discharge ports of the feeders 35 and 36 can be inclined in the direction of approaching each other. It can be that the discharge port of the feeder 35 is inclined towards the feeder 36, or vice versa. It can also be that the discharge port of the feeder 35 is inclined towards the discharge port of the feeder 36 while the discharge port of the feeder 36 is inclined towards the discharge port of the feeder 35, or the discharge ports of the feeders 35 and 36 are respectively inclined towards the rotation axis direction of the material table frame 20 or towards the direction of the material table bin through hole 391. As Figure 5 shown in [reference], the feeding pipes 37 led out from the discharge port of the feeder 35 and the feeding pipe 38 led out from the discharge port of the feeder 36 are inclined while approaching each other simultaneously, as Figure 4The printing material 33 sent out by the feeder 33 and the printing material 34 sent out by the feeder 36 are sent out obliquely in a direction of approaching each other simultaneously. In this way, after the feed pipes 37 and 38 are led out from the discharge ports of the feeder 35 and the feeder 36, they can approach and fit with each other within a short downward distance, reducing the downward extension length of the feed pipes bending towards each other, which is beneficial to reducing the distance between the feeder and the printing head below, and also beneficial to reducing the distance between the feeder and the through hole 391 of the material table bin, and beneficial to reducing the volume of the material table bin 39 and the volume of the 3D printing device. Generally, the bottom of the nozzle seat 71 includes at least two extrusion ports for extruding the printing material; at least two feeding drives are arranged on the material table frame 20. The two feeding drives are arranged on the material table frame 20 and can rotate together with the material table frame 20. The two feeding drives are used to convey the printing material to the two extrusion ports respectively; the directions of the discharge ports of the two feeding drives for sending out the wire materials are obliquely downward and approaching each other (that is, the discharge port of at least one path discharges obliquely towards the discharge port of the other path, or the discharge ports of the two paths discharge obliquely in a direction of approaching each other simultaneously), or the discharge ports of the two feeding drives are obliquely downward and towards the direction of the rotation axis of the material table frame 20. Downward refers to the direction towards the printing head along the rotation axis of the material table frame. Such a setting makes the filamentous printing materials (wire materials) sent out by the two feeding drives approach each other within a short distance, which is beneficial to merging multiple wire materials together and sending them to the printing head, and has greater angular adaptability to the rotation of the printing head. That is, when the printing head has the same rotation angle, the torsional moment between multiple wire materials is smaller, the torsional deformation of the wire materials is smaller, and the transmission of the wire materials to the printing head is smoother, which can greatly reduce the rotation angle range of the material table following the printing head. It is beneficial to reduce the rotation time or angular velocity of the material table, or reduce the fluctuation of the rotation of the material table. It is also beneficial to reduce the process or transmission length of the feed pipes bending towards each other, beneficial to reducing the distance between the material table and the printing head, and beneficial to reducing the volume of the printing device.

[0062] The feeding drive is used to drive the filamentous printing material to feed and convey along the axis. The two feeding drives can be two feeders, or one feeder can drive two paths of printing materials simultaneously. For example, the two feeding drives can include a first feeder and a second feeder. A first material tray and a second material tray can also be arranged on the material table frame 20. The first feeder conveys the printing material on the first material tray to the first extrusion port, and the second feeder conveys the printing material on the second material tray to the second extrusion port.

[0063] Figure 6 Schematic diagram along the direction perpendicular to the rotation axis 91 of the material table frame. The axis 91 is perpendicular to the drawing plane, that is Figure 6This is a bottom view, i.e., the rotation axis 91 is perpendicular to the drawing plane. The material trays 31, feeders 35, material tray 32, and feeders 36 are arranged in a circular sequence around the rotation axis 91 of the material platform frame. Preferably, the drive motor 351 of the feeder 35 is arranged in a direction away from the rotation axis 91 of the material platform frame relative to the feeder 35, and the drive motor 361 of the feeder 36 is arranged in a direction away from the rotation axis 91 of the material platform frame relative to the feeder 36. In this way, it has a better compact spatial arrangement, a small moment of inertia, relatively better dynamic balance during rotation, and since the feeder 35 relative to the drive motor 351 and the feeder 36 relative to the drive motor 361 are both arranged inward (close to the axis 91), the material feeding outlets of the two feeders are closer, and the two feeding pipes can be better brought together to convey materials to the print head.

[0064] Figure 9 Schematically shows a control method. First, in step 95, based on the 3D model data of the printing model 40, slicing processing is performed to generate a rotation instruction for the nozzle seat 71, and at the same time, a rotation instruction for the material platform frame 20 is also generated. The rotation instruction for the nozzle seat 71 can also be called the rotation instruction for the print head, and the rotation instruction for the material platform frame 20 can also be called the rotation instruction for the material platform. The slicing processing of the 3D model of the printing model 40 is to cut the three-dimensional model into multiple two-dimensional slices by processing the 3D model data, providing corresponding data for layer-by-layer construction of the object. For example, the 3D digital model is processed layer by layer to generate a vector set or converted into G-code instructions. The rotation instruction for the nozzle seat 71 and the rotation instruction for the material platform frame 20 can be numerical control languages, such as G-code (G-code) or RS-274, or other instructions executable by a chip (such as a CPU). Then, in step 96, the rotation instruction (n1, n2, n3, …) for the nozzle seat 71 and the rotation instruction (m1, m2, m3, …) for the material platform frame 20 are transmitted to the controller of the 3D printing device, for example Figure 1 or Figure 3The controller 54 in it controls the rotation drive mechanism of the nozzle seat (step 97) to drive the nozzle seat 71 to rotate relative to the printing seat 72 and controls the rotation drive mechanism of the material table frame 20 (step 98) to drive the material table frame 20 to rotate following the nozzle seat 71. Since flexible lines (such as the feed pipe 37 or the wire 52, etc.) have a certain elasticity, the rotation of the material table frame 20 following the nozzle seat 71 does not have to be completely synchronous. During the high-frequency and small-angle rotation of the nozzle seat 71, the material table frame 20 can rotate at a low speed or not rotate. But generally, the angle difference between the material table frame 20 and the nozzle seat 71 should be less than or equal to a preset value. The angle difference between the material table frame 20 and the nozzle seat 71 can also be expressed as the angle difference between the material table and the print head. When the preset value is 0, the material table frame 20 rotates completely synchronously following the nozzle seat 71. For example, when the rotation of the nozzle seat 71 is stable, the material table frame 20 can also rotate completely synchronously following the nozzle seat 71. During the printing process, the feeding component on the material table frame 20 conveys the printing material to the extrusion port on the nozzle seat through a flexible line.

[0065] Figure 10 The schematic control method only generates the rotation instruction of the nozzle seat 71 when slicing the 3D model data of the printing model in step 95, and then generates the rotation instruction of the material table frame 20 (m1, m2, m3,...) in step 96 according to the rotation instruction of the nozzle seat 71 (n1, n2, n3,...). n1, n2, n3,... and m1, m2, m3,... can respectively represent the G-code sequence. The process of generating the rotation instruction of the material table frame 20 can be generated in the controller 54 or in the computer system for slicing the 3D model data of the printing model 40, and then the controller 54 simultaneously controls the rotation drive mechanism of the nozzle seat 71 (step 97) to drive the nozzle seat 71 to rotate relative to the printing seat 72 and controls the rotation drive mechanism of the material table frame 20 (step 98) to drive the material table frame 20 to rotate following the nozzle seat 71.

[0066] The controller can control the rotation drive mechanisms of the nozzle seat 71 and the material table frame 20 by using electrical pulses. The electrical pulses can be voltage pulses or current pulses. For example, the pulse width modulation PWM (Pulse Width Modulation) signal is used to control the switching tube, such as the MOSFET tube (Metal - Oxide - Semiconductor Field - Effect Transistor), to control the driving of the stepping motor or the permanent magnet synchronous motor to rotate, etc. The rotation drive mechanisms of the nozzle seat 71 and the material table frame 20 can use a stepping motor or a permanent magnet synchronous motor to drive the print head or the material table to rotate, such as through a synchronous belt or a gear pair, etc.

[0067] During the process of printing a preset printing path of a certain printing layer, when the print head moves along the preset printing path, the print head (the nozzle seat 71 of the print head) may rotate a preset angle. However, the rotation process may be sometimes fast and sometimes slow, and may even occasionally rotate in the reverse direction. The material platform (the material platform frame 20 of the material platform) can maintain a one-way rotation or a uniform rotation in the same direction as the combined rotation direction (preset angle direction) of the print head during the time it takes for the print head to complete the preset path, with an error not exceeding ±40%.

[0068] During the process of printing the contour of a certain printing layer, the print head (the nozzle seat 71 of the print head) may rotate one full circle. As Figure 7 shown, during the movement of the print seat 72 of the print head, the nozzle seat 71 rotates. As shown by the arrow θ, after the print head moves one full circle along the printing path 90, the nozzle seat 71 may rotate one full circle along the arrow θ. However, the rotation process may be sometimes fast and sometimes slow, and may even occasionally rotate in the reverse direction. The material platform (the material platform frame 20 of the material platform) can maintain a one-way rotation or a uniform rotation in the same direction as the combined rotation direction of the print head during the time it takes for the print head to complete one full rotation and complete approximately one full rotation. That is, during the process of printing the closed contour printing path of the printing layer of a three-dimensional model, when the print head moves one full circle along the closed contour printing path, the nozzle seat of the print head also rotates one full circle. During this process, the material platform can follow the print head to rotate one full circle in one direction or rotate one full circle uniformly, that is, the material platform frame 20 follows the nozzle seat 71 to rotate one full circle in one direction or rotate one full circle uniformly, with an error not exceeding ±40%.

[0069] During the process of printing the contour of a certain printing layer, the print head (the nozzle seat of the print head) may rotate several full circles. As Figure 8 shown, during the movement of the print seat 72 of the print head, the nozzle seat 71 rotates. As shown by the arrow θ, when moving along the printing path 90, after the print head moves several full circles along the printing path 90, the nozzle seat 71 may rotate several full circles along the arrow θ. However, the rotation process may be sometimes fast and sometimes slow, and may even occasionally rotate in the reverse direction. The material platform (the material platform frame) can maintain a one-way rotation or a uniform rotation in the same direction as the combined rotation direction of the print head during the time it takes for the print head to complete several full rotations and complete the corresponding approximate rotation of several full circles, with an error not exceeding ±40%.

[0070] Too fast rotation of the material platform or rotation with too large an acceleration can easily cause the oscillation or vibration of the feeding devices such as the feeding tray on the material platform, and can also easily cause the vibration of the entire device, affecting the printing accuracy, the running stability and reliability of the device, and may also affect the printing speed. Therefore, the material platform may not always rotate synchronously with the nozzle seat. When the angular difference between the material platform and the nozzle seat 71 of the print head increases, the rotation of the material platform can be started or the rotation speed of the material platform can be increased. When the angular difference between the material platform and the nozzle seat 71 of the print head decreases, the rotation of the material platform can be stopped or the rotation speed of the material platform can be decreased. When the angular velocity and angular acceleration of the print head are respectively less than the preset values, the material platform rotates synchronously with the print head. The rotation of the print head or the rotation of the material platform respectively refers to the rotation of the nozzle seat 71 of the print head or the rotation of the material platform frame 20. The rotation angle of the print head or the rotation angle of the material platform respectively refers to the rotation angle of the nozzle seat 71 of the print head or the rotation angle of the material platform frame 20.

[0071] When the rotation of the material platform following the print head causes the angular velocity or angular acceleration of the material platform to be greater than the preset value, if the rotation direction of the print head is the first direction (for example, one of clockwise or counterclockwise), the material platform rotates in advance in the first direction and uses a longer rotation time to reduce the angular velocity or angular acceleration of the material platform; or when the print head rotates to the preset rotation angle, the material platform has not completed the rotation to the preset rotation angle, but the material platform continues to rotate in the first direction until the rotation of the preset rotation angle is completed, and a longer rotation time is used to reduce the angular velocity or angular acceleration of the material platform.

[0072] The rotation or revolution of the print head refers to the rotation or revolution of the nozzle seat 71 of the print head relative to the print seat; the rotation or revolution of the material platform can refer to the rotation or revolution of the material platform frame 20, for example, the rotation or revolution relative to the base frame 11.

[0073] Further, a threshold control method; the absolute value of the angular difference between the material platform and the nozzle seat 71 of the print head is used as the control target. When the absolute value D of the actual angular difference is greater than or equal to the preset value K1, the material platform starts to rotate to reduce the absolute value of the angular difference. When the absolute value D of the actual angular difference is less than the preset value K2, the material platform stops rotating, and K2 is less than or equal to K1. Or a feedback control method; the angular difference d between the material platform and the nozzle seat 71 of the print head is detected, and d×C is used as the driving rotation signal of the material platform. Further, C is a constant value, or C increases as the absolute value of d increases and decreases as the absolute value of d decreases. Or a pre-judgment control method: The rotation of the print head can also be pre-judged. Since the rotation of the print head is preset and known in advance, according to the rotation instruction sequence of the nozzle seat 71 within a period of time, the material platform can be rotated in advance relative to the nozzle seat 71. For example, when a series of rotation control instructions for the nozzle seat 71, such as sequence n, n + 1, n + 2... and other series of control steps, when the nozzle seat 71 is going to rotate clockwise by a certain angle within the current or future t time, the material platform can rotate clockwise before the current step and can rotate at a lower speed. The advantage of this is that the acceleration and angular velocity (whether it is the average angular velocity or the maximum angular velocity) during the rotation of the material platform can be further reduced! In this way, the rotational angular acceleration and / or angular velocity of the material platform frame 20 can be minimized.

[0074] According to the sequence of rotation angles in the print head rotation control instruction (such as G code), several sequences are averaged to obtain the rotation angle P. Some small and frequent forward and reverse rotations may be canceled. When the rotation angle P is greater than or equal to the preset value, the material platform rotates. When the rotation angle P is less than the preset value, the material platform does not rotate. Or, the sequence of rotation angles in the instruction for controlling the rotation of the print head is averaged to obtain the rotation angle P. During the time span of this sequence, the material platform follows the print head to rotate the rotation angle P unidirectionally or at a constant speed, and the error is not greater than ±40%. The rotation direction of the material platform is judged according to the sign of the rotation angle P.

[0075] The angular difference between the material platform frame 20 of the material platform and the nozzle seat 71 of the print head is used as the control target to control the material platform to follow the rotation of the print head. When the absolute value of the angular difference between the material platform and the nozzle seat 71 is greater than the start threshold K, the material platform starts to follow the rotation, and the rotation direction of the material platform is determined according to the sign (positive or negative) of the angular difference, so that this absolute value is reduced. When the rotation of the print head reduces this absolute value, the material platform does not need to rotate. Only when the rotation of the print head makes this absolute value greater than the preset value does the material platform follow the rotation. When the angular difference between the material platform and the nozzle seat 71 is less than the stop threshold T, the material platform stops following the rotation. Preferably, the stop threshold T is less than or equal to the start threshold K. The start threshold K can be 0. For example, when the rotational angular velocity of the nozzle seat 71 is less than the threshold R1, the start threshold K can be 0, that is, the material platform completely follows the rotation of the nozzle seat 71.

[0076] The greater the lagging angular difference between the material stage frame and the nozzle seat 71, the greater the rotational speed of the material stage frame; the longer the duration of the lagging angular difference between the material stage frame and the nozzle seat 71, the greater the rotational speed of the material stage frame 20; the greater the increasing direction of the change of the lagging angular difference between the material stage frame and the nozzle seat 71, the greater the rotational speed of the material stage frame 20.

[0077] Within the preset printing process time range or the preset printing path distance, the rotation of the nozzle seat may be sometimes fast and sometimes slow during the rotation process, and may even reverse rotation occasionally (for example, temporarily changing from clockwise rotation to counterclockwise rotation). If the combined rotation result of the nozzle seat 71 is in the preset direction (combined rotation direction) (for example, clockwise direction), the material stage frame can rotate uniformly in the preset direction. At the end of the preset printing process time range or the preset printing path distance, the material stage frame rotates to the preset angle, and the preset angle is equal to the combined rotation angle value of the nozzle seat 71 within the preset printing process time range or the preset printing path distance, with an error not greater than ±40%; in the next preset printing process time range or the preset printing path distance, repeat the above process. In this way, the number of start-stop times of the rotation of the material stage frame can be greatly reduced, and the rotation smoothness of the material stage frame can be greatly improved.

[0078] A printing method, step 1: At the start or before the start of printing, first detect the angular difference between the material stage and the print head, and adjust it to be less than or equal to the initial preset value (the initial preset value can be 0); step 2, start the printing process, and use the material stage rotation control method described above in this article to control the material stage to rotate following the print head. It should be noted that the angular difference between the material stage and the print head refers to the angular difference between the material stage frame of the material stage and the nozzle seat on the print head.

[0079] Generally speaking, in this control method, the rotation instruction of the nozzle seat 71 (the rotation instruction of the print head) and the rotation instruction of the material stage frame 20 (the rotation instruction of the material stage) are directly generated according to the printing model 40, or the rotation instruction of the nozzle seat 71 is first generated and then the rotation instruction of the material stage frame 20 is generated from the rotation instruction of the nozzle seat 71. Finally, the rotation of the nozzle seat 71 and the rotation of the material stage frame 20 are respectively controlled by the rotation instruction of the nozzle seat 71 and the rotation instruction of the material stage frame 20 at the same time, or the controller controls the rotation drive mechanism of the material stage frame 20 after transformation processing according to the rotation instruction of the nozzle seat 71. In this way, the control process of the controller can be greatly simplified during the printing and control process, the information communication burden of the control process can be simplified, and the control is more accurate and optimized. Since the printing path situation can be more thoroughly understood according to the data of the printing model 40 in advance, a more optimized rotation control method for the rotating material stage can be given, which can make the rotation process of the material stage frame 20 more stable and minimize the combined angular difference between the material stage frame 20 and the nozzle seat 71 at each time period. Even during the printing process, it is not necessary to detect the rotation angle of the nozzle seat 71 or the material stage frame 20, simplifying the system and the control process.

[0080] The feed pipe 37, the air supply pipe 44, the ink supply pipe, etc. are all made of flexible pipes with elasticity. For example, pipes made of polytetrafluoroethylene (Teflon) can be used.

[0081] In the text, descriptions such as "vertical", "parallel", or "equal" refer to being precisely accurate in theory, but in actual production or installation, there are errors, such as the error being less than ±45 degrees, or less than ±30 degrees, or less than ±15 degrees, or not greater than ±50%, ±40%, ±30%, ±20%, or ±10%. The directional terms such as "up", "down", "left", and "right" used in the text are for the convenience of description based on the specific drawings and do not limit the present invention. In practical applications, due to the transformation of the overall structure in space, the actual left or right position may be different from that in the drawings. However, all these transformations should be within the protection scope of the present invention.

[0082] The printing material, such as filamentous printing material (or called filament material) or granular material, can be a thermoplastic resin material, such as PLA (polylactic acid), PP (Polypropylen), PE (polyethylene), ABS (Acrylonitrile Butadiene Styrene), PA (Polyamide) (nylon), PC (Polycarbonate), PS (Polystyrene), PEI (Poly(etherimide)), PET (Poly(Ethylene Terephthalare)), PEEK (Polyetheretherketone), TPU (Thermoplastic polyurethanes), etc.; or an elastic material, such as thermoplastic elastomer (TPE), styrene-butadiene rubber (SBR), and styrene-butadiene block copolymer (SBS), etc., or thermoplastic polyurethane (TPU) or thermoplastic vulcanizate (TPV); of course, it can also be a thermosetting resin material or a photosensitive polymeric resin material, or other materials that can be extruded by flowing. The filament material can also be a continuous fiber printing material (or called continuous fiber filament material), which can be a fiber material, a metal wire material (such as copper wire), an optical fiber material, or other continuous linear materials, and can be a continuous fiber material pre-impregnated with resin. The continuous fiber material is, for example, carbon fiber, glass fiber, polyester, aramid, ceramic fiber, boron fiber, or basalt fiber, etc. The diameter of the filamentous printing material can be 1.75 mm or 3 mm, or other diameters, and the diameter of the extrusion port can be 0.4 mm, 0.5 mm, or other diameter sizes.

[0083] Parts not involved in the present invention are the same as or can be implemented by using the prior art. The above are only preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the above-disclosed technical content. However, as long as it does not depart from the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for controlling the rotation of a feeding table, characterized in that, A print head, a material platform, a controller, a first driving mechanism and a second driving mechanism are provided. The print head includes a print base and a nozzle base. The nozzle base is rotatably arranged on the print base. At least one extrusion port is arranged at the bottom of the nozzle base, and at least one of the extrusion ports is used for extruding printing material; the material platform includes a material platform frame, a base frame and at least one feeding component. The material platform frame can rotate relative to the base frame. The feeding component is arranged on the material platform frame and rotates together with the material platform frame. The feeding component is used for conveying printing material to at least one of the extrusion ports; the first driving mechanism is used for driving the nozzle base to rotate, the second driving mechanism is used for driving the material platform frame to rotate, and the controller is used for controlling the first driving mechanism and the second driving mechanism; A flexible circuit is connected between the material platform frame of the material platform and the nozzle base of the print head. The flexible circuit includes a printing material transmission circuit formed between the feeding component and at least one of the extrusion ports for transmitting printing material; The method includes the following steps: the three-dimensional model to be printed is subjected to slicing processing to generate a rotation instruction for the print head. During the printing process, the controller controls the first driving mechanism to drive the nozzle base to rotate according to the rotation instruction of the print head, and controls the second driving mechanism to drive the material platform frame to rotate following the nozzle base according to the rotation instruction of the print head, so that the angle difference between the material platform and the print head is less than or equal to a preset value; or, the three-dimensional model to be printed is subjected to slicing processing to generate a rotation instruction for the print head and a rotation instruction for the material platform. During the printing process, the controller controls the first driving mechanism to drive the nozzle base to rotate according to the rotation instruction of the print head, and controls the second driving mechanism to drive the material platform frame to rotate following the nozzle base according to the rotation instruction of the material platform, so that the angle difference between the material platform and the print head is less than or equal to a preset value.

2. The material table rotation control method according to claim 1, wherein During the printing process, the print head moves along a preset printing path, the nozzle base of the print head rotates by a preset rotation angle, and the material platform frame of the material platform rotates by the preset rotation angle in one direction or rotates at a constant speed by the preset rotation angle along the preset rotation angle direction within the time taken for the print head to complete the preset path, with an error not greater than ±40%.

3. The material table rotation control method according to claim 2, wherein, During the process of printing the closed contour printing path in the printing layer of the three-dimensional model, the print head moves along the closed contour printing path for one week, the nozzle base of the print head rotates for one week, and the material platform frame of the material platform rotates for one week in one direction or rotates at a constant speed for one week, with an error not greater than ±40%.

4. The material table rotation control method according to claim 1, wherein When the angle difference between the material platform and the print head increases, start the rotation of the material platform or accelerate the rotation of the material platform. When the angle difference between the material platform and the print head decreases, stop the rotation of the material platform or slow down the rotation of the material platform; or, When the rotational angular velocity and angular acceleration of the print head are respectively less than a preset value, the material platform rotates synchronously with the print head; or, When the synchronous following of the material platform with the rotation of the print head causes the angular velocity or angular acceleration of the material platform to be greater than a preset value, assuming the rotation direction of the print head is the first direction, the material platform rotates in advance in the first direction and uses a longer rotation time to reduce the rotational angular velocity or angular acceleration of the material platform; or when the print head has completed a preset rotation angle, the material platform has not completed the rotation of the preset rotation angle, and the material platform continues to rotate in the first direction until the rotation of the preset rotation angle is completed, using a longer rotation time to reduce the rotational angular velocity or angular acceleration of the material platform.

5. The method for controlling the rotation of the material platform according to claim 1, wherein a threshold control method is adopted: the absolute value of the angle difference between the material platform frame of the material platform and the nozzle seat of the print head is used as the control target. When the absolute value of the angle difference is greater than or equal to a first preset value, the material platform starts to rotate to reduce the absolute value of the angle difference. When the absolute value of the angle difference is less than a second preset value, the material platform stops rotating, and the second preset value is less than or equal to the first preset value; or a feedback control method is adopted: the angle difference d between the material platform frame of the material platform and the nozzle seat of the print head is detected, and d×C is used as the driving rotation signal of the material platform, where C is a constant value or C increases as the absolute value of d increases and decreases as the absolute value of d decreases; or a pre-judgment control method is adopted: the rotation of the print head is pre-judged, and according to the rotation instruction sequence of the print head, the material platform frame of the material platform is made to rotate in advance relative to the nozzle seat of the print head; or a field instruction control method is adopted: the three-dimensional model to be printed is sliced to generate the rotation instruction of the print head. Before printing the print model or a partial print layer, the rotation instruction of the material platform is generated according to the rotation instruction of the print head; During the printing process, the first driver is controlled according to the rotation instruction of the print head to drive the nozzle seat of the print head to rotate, and the second driver is controlled according to the rotation instruction of the material platform to drive the material platform frame of the material platform to rotate.

6. The method for controlling the rotation of the material platform according to claim 1, wherein the sequence of the rotation angles in the rotation instruction of the print head is equalized to obtain the rotation angle P. When the rotation angle P is greater than or equal to a first preset value, the material platform rotates. When the rotation angle P is less than a second preset value, the material platform does not rotate, and the first preset value is greater than or equal to the second preset value; or the sequence of the rotation angles in the rotation instruction of the print head is equalized to obtain the rotation angle P. During the time span of this sequence, the material platform follows the rotation of the print head by the rotation angle P unidirectionally or uniformly, with an error not greater than ±40%, and the rotation direction of the material platform is judged according to the sign of the rotation angle P.

7. The material table rotation control method according to claim 1, wherein, Within a preset printing process time range or a preset printing path distance, if the combined rotation result of the nozzle seat is towards the preset direction, the material platform frame can rotate uniformly towards the preset direction. At the end of the preset printing process time range or the preset printing path distance, the material platform frame rotates by a preset angle, and the preset angle is equal to the combined rotation angle of the nozzle seat within the preset printing process time range or the preset printing path distance, with an error not greater than ±40%. For the next preset printing process time range or preset printing path distance, repeat the above process.

8. The material table rotation control method according to claim 1, characterized in that The rotation instruction of the print head and / or the rotation instruction of the material platform adopt G-code; and / or, The controller controls the first driver and the second driver using electrical pulses.

9. A 3D printing method, characterized in that, It includes the following steps: S1: At the start or before the start of printing, first detect the angle difference between the material platform and the print head, and adjust the angle difference to be less than or equal to the initial preset value; S2: Start the printing process, and use the material platform rotation control method described in any one of claims 1 to 9 to control the material platform to rotate following the print head.

10. A 3D printing device, characterized in that, Using the material platform rotation control method described in claim 1 or the 3D printing method described in claim 9, at least two extrusion outlets are provided at the bottom of the nozzle seat, and at least two of the extrusion outlets are respectively used for extruding printing materials; wherein, At least two feeding drives are provided on the material platform frame. The two feeding drives are arranged on the material platform frame and can rotate together with the material platform frame. The two feeding drives are respectively used to convey filamentous printing materials to at least two of the extrusion outlets; the directions of the discharge ports of the filamentous printing materials respectively conveyed by the two feeding drives are inclined downward and approaching each other, or the discharge ports of the two feeding drives are inclined downward towards the direction close to the rotation axis of the material platform frame; Or, A first material tray, a first feeder, a second material tray, and a second feeder are provided on the material platform frame. The first material tray, the first feeder, the second material tray, and the second feeder are arranged in sequence around the rotation axis of the material platform frame in a circumferential manner. The drive motor of the first feeder is arranged in a direction away from the rotation axis of the material platform frame relative to the first feeder, and the drive motor of the second feeder is arranged in a direction away from the rotation axis of the material platform frame relative to the second feeder.

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