Printing head for 3D printing, control system, 3D printer and printing method

[0082] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0083] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise" and other directions or positions indicated The relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore It cannot be understood as a limitation to the present invention.

[0084] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , Or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] See figure 1 , The present invention provides a print head for 3D printing, including a housing 180, a screw extrusion system 120 and a telescopic nozzle valve. The telescopic nozzle valve is divided into two types according to the presence or absence of a nozzle structure 280, one is no nozzle Telescopic nozzle valve, the other is the nozzle telescopic nozzle valve. One end of the casing 180 is provided with a driving system 110; the screw extrusion system 120 is provided in the casing 180, and the screw extrusion system 120 is composed of at least two screws nested inside and outside, wherein, At least one screw is driven by the drive system 110; the telescopic nozzle valve is arranged under the screw extrusion system 120 and under the casing 180, and the material extruded by the screw extrusion system 120 is telescopic The nozzle valve flows out. The screw extrusion system 120 converts the input material into a molten material, and flows out through a telescopic nozzle valve that can be closed. The telescopic nozzle valve can be set to be multi-channel. In this way, the output diameter of each channel is different, and the appropriate diameter can be selected according to the needs to achieve the balance of printing accuracy and speed.

[0086] Specifically, see figure 2 , The screw extrusion system 120 includes a first-stage screw 1201, a second-stage screw 1202, and a third-stage screw 272 from the outside to the inside, that is, a triple screw; the first-stage screw 1201 and the second-stage screw 1202 are respectively provided with air Cavity (and whether the third-stage screw 272 has a cavity structure is not limited); a first-stage hot runner is formed between the casing 180 and the first-stage screw 1201, and a second-stage hot runner is formed between the second-stage screw 1202 and the first-stage screw 1201 A three-stage hot runner, a three-stage hot runner 211 is formed between the three-stage screw 272 and the two-stage screw 1202; the third-stage hot runner 211 is in communication with the discharge manifold 2111; the first-stage hot flow The two-stage hot runner, the second-stage hot runner, and the third-stage hot runner 211 are connected in series to form a continuous N-shaped channel; one or more of the first-stage screw 1201, the second-stage screw 1202, and the third-stage screw 272 are driven to rotate by the driving system 110 . Wherein, the first-stage screw 1201 is driven by the driving system 110; the second-stage screw 1202 and the casing 180 are in a static state. The cross-sectional area of ​​the primary hot runner and/or secondary hot runner and/or tertiary hot runner 211 gradually decreases along the material flow direction. A telescopic nozzle valve is connected below the three-stage screw 272, and the nozzle 260 system and the three-stage hot runner 211 are in a conductive state; both sides of the nozzle 260 system are also provided with a pressure sensor 161 and a flow sensor 162 respectively. A raw material inlet 150 is provided on one side of the casing 180, and the raw material inlet 150 is also connected to a feeding system 151. The feeding system 151 is a pneumatic feeding system 151. The system 151 transports granular or powdered materials to the raw material inlet 150 and sequentially passes through the primary hot runner, secondary hot runner, tertiary hot runner 211, and nozzle 260 systems. At the intersection of the secondary hot runner and the tertiary hot runner is also provided with at least one micropore for discharging gas in the material. The outer side of the casing 180 is also provided with a heating device. The driving system 110 is a geared motor; the geared motor is detachably connected to the primary screw 1201 through a flange. A feeding cone 1801 is formed on the casing 180 and close to the feeding end of the first-stage hot runner to increase the feeding speed. In addition, the theoretical extrusion volume of the material in the primary hot runner is greater than the theoretical basis volume of the material in the secondary hot runner, and the theoretical extrusion volume of the material in the secondary hot runner is greater than the theoretical extrusion of the material in the tertiary hot runner 211. The theoretical extrusion volume of the material in the third-stage hot runner 211 is within the rated extrusion volume threshold range of the material. To achieve the same extrusion volume, the spiral angle of the first-stage screw 1201 is gentler than that of the second-stage screw 1202 and the third-stage screw 272, so that the material is not easy to slide in the first-stage hot runner, while the material is in the second-stage hot runner and third-stage hot flow Although it is easy to slide in the channel, the material in the first-level hot runner produces a blocking effect to prevent the material from moving in the opposite direction, which cannot be achieved with a single screw.

[0087] By setting at least two screws to form a multi-rotation extrusion mechanism, the length of material conveying can be extended in a small space, the heating time and mixing time are prolonged, and the material can be heated and melted and mixed more thoroughly. And because the spiral angle is set in three levels, it is conducive to the stable transportation of materials. When in use, the driving system 110 is located above the casing 180. Due to the multiple bending of the material transportation, the mixing effect of the material is better. According to an embodiment of the present invention, one or more of the first-stage screw 1201, the second-stage screw 1202, and the third-stage screw 272 are driven to rotate by the driving system 110. A triple screw is provided, which is a preferred embodiment of the present invention.

[0088] In terms of further development, multiple driving systems 110 may be provided, such as driving system 1, driving system 2, and driving system 3. In this way, each driving system drives a screw. Alternatively, drive system one and drive system two are set, drive system one drives the first-stage screw, and drive system two drives the third-stage screw, while the two-stage screw is in a fixed state. In addition, as a degraded implementation, the drive system alone drives the three-stage screw, so that the implementation of the present invention can also be ensured. In addition, it should be pointed out that the present invention can also be equipped with a four-fold screw, five-fold screw, six-fold screw or more screws to further enhance the function of the present invention. It is foreseeable that by further increasing the number of screws, the length of the extruder can be further reduced, but this is also accompanied by increased processing difficulty. In addition, if more screws are installed, the width of the extruder will increase.

[0089] The nozzleless telescopic nozzle valve is described: the telescopic nozzle valve includes a mounting seat 210, a cylinder 220, a valve needle 230, and a nozzle 260, wherein the mounting seat 210 is detachably mounted on the screw extrusion system 120 The upper section of the mounting seat 210 is provided with a three-stage hot runner 211, the end of the three-stage hot runner 211 is provided with a discharge manifold 2111, and the lower end of the mounting seat 210 has one or A plurality of inner holes, the discharge manifold 2111 respectively communicates with the upper end of each inner hole, and the lower end of the inner hole is an opening toward the outside; the cylinder 220 is movably installed on the mounting seat 210 In the inner hole, the cylinder 220 extends from one end of the mounting seat 210, the top of the cylinder 220 is provided with at least one cylinder inlet 2401; the cylinder 220 is provided with a valve cavity; the valve needle 230 passes through the valve cavity of the cylinder 220 and is installed on the mounting seat 210, and the gap between the valve needle 230 and the valve cavity forms a discharge channel 240 that is in communication with the cylinder inlet 2401; The nozzle 260 is provided at the tail of the cylinder 220, and the nozzle 260 is provided with a nozzle hole 2631 at the tail. More detailed description: The upper and lower sections of the mounting seat 210 are respectively provided with an upper sealing member 2201 and a lower sealing member 2202 where they are in contact with the outer periphery of the upper section and the outer periphery of the lower section of the cylinder 220. The seal 2202 is a groove filled with expanded graphite. The cylinder 220 also has a cylinder cylinder 221 in the middle section between the upper seal 2201 and the lower seal 2202 (when specifically manufactured, the cylinder cylinder 221 is a piston); the cylinder cylinder At least one annular groove 2211 is provided on the side wall of 221; the annular groove 2211 is filled with a sliding sealing material to make the cylinder 220 and the mounting seat 210 hermetically connected. The sliding sealing material is a solid sliding sealing material, such as expanded graphite. There is a first fluid chamber 251 between the cylinder cylinder 221 and the upper seal 2201, and a second fluid chamber 252 is provided between the cylinder cylinder 221 and the lower seal 2202; the first fluid chamber 251 passes through the first fluid chamber 251. The fluid through hole 2511 is connected to the first fluid valve; the second fluid chamber 252 is connected to the second fluid valve through the second fluid through hole 2521. The head or one side of the valve needle 230 is fixed to the mounting seat 210 by at least one (preferably two) positioning bolts 231. The upper section of the cylinder 220 is provided with a limit through groove 2402, and the limit through groove 2402 and the limit key 232 on the top side of the valve needle 230 slidably cooperate to make the cylinder body inlet 2401 and the outlet manifold 2111. Aligned. The valve needle 230 has an inverted L shape. An electric heating device 130 is provided on the outside of the mounting seat 210 to achieve a heat preservation effect. The upper section of the mounting seat 210 includes a three-stage hot runner 211; the third-stage hot runner 211 is also provided with a three-stage screw 272; the lower end of the three-stage hot runner 211 and the discharge manifold 2111, the barrel The feeding port 2401, the discharging channel 240, and the nozzle hole 2631 are connected in sequence. The mounting seat 210 is arranged in sections, and the sections are fixedly connected by locking bolts. The mounting base 210 and the casing 180 are fixed by bolts.

[0090] The above embodiments describe a nozzleless print head for 3D printing. The difference between the 3D printing print head with nozzle and the 3D printing print head without nozzle is that it also includes a hollow nozzle structure 280 provided under the mounting seat 210. Wherein, the tuyere structure 280 is divided into tuyere avoidance section 2801, tuyere sealing section 2802, and air outlet section 2803 from top to bottom; the tail of the printing nozzle 260 is provided with a nozzle hole 2631, and the nozzle 260 is divided into The nozzle avoiding section 261, the nozzle sealing section 262 and the nozzle protruding section 263 that cooperate with the nozzle sealing section 2802; the nozzle structure 280 is installed around the outside of the nozzle 260; on the nozzle structure 280 An air inlet channel 264 for supplying air to the tuyere structure 280 is provided. Wherein, a ventilation space is formed between the nozzle avoiding section 261 and the tuyere avoiding section 2801. At this time, one or more nozzles 260 may be provided on the tuyere structure 280. If multiple printing nozzles 260 are provided, the nozzles 260 are arranged at intervals, such as in a linear or circular arrangement. The nozzle 260 moves under power. When the nozzle sealing section 2802 and the nozzle sealing section 262 are in an unsealed mating state, the air inlet channel 264 supplies air to the air outlet section 2803, and the air outlet section 2803 is cylindrical, and the gas is ejected from the air outlet section 2803 and passes through the printing nozzle 260, while acting on the newly extruded material. When the nozzle 260 moves downward, the printing nozzle 260 starts to flow out the 3D printing material and realizes the air flow. When the nozzle 260 moves upward to the position where the nozzle sealing section 2802 and the nozzle sealing section 262 are in sliding fit and seal , The nozzle 260 immediately stops flowing out of the 3D printing material, and immediately stops blowing out. Due to the mechanical force for shearing, the discharging stops immediately and the air discharge stops immediately. The setting position of the air inlet channel 264 is further limited: the air inlet channel 264 is provided on the side or top of the upper section of the air nozzle sealing section 2802, when the 3 nozzles 260 move upward to the air nozzle sealing section 2802 and the nozzles When the sealing section 262 is slidably fitted to the sealing part, the air inlet channel 264 cannot discharge air to the air outlet section 2803. When the nozzle 260 moves down until the air nozzle sealing section 2802 and the nozzle sealing section 262 are out of cooperation, The air nozzle sealing section 2802 and the nozzle sealing section 262 are separated from each other to form a ventilating space, and the air inlet passage 264 passes through the ventilating space to discharge air to the air outlet 2803.

[0091] In addition, the lateral width of the nozzle protrusion section 263 is smaller than the opening width of the air outlet section 2803 of the air nozzle structure 280 to form an air outlet gap (air outlet space), such as a cone or hemispherical shape. In addition, in order to play a better guiding role, the telescopic nozzle avoiding section 261 and the tuyere avoiding section 2801 also need to be partially slidable in contact. The contact part plays a guiding role when sliding, and the non-contact part forms the wind space. In order to further enhance the air outlet effect, a plurality of spiral grooves are provided on the outer contour surface of the nozzle avoiding section 261 to form a spiral wind, thereby improving the cooling effect. As an optimal solution: the inner contour of the air nozzle avoiding section 2801 is a cylindrical surface, and the outer contour of the nozzle avoiding section 261 is an arc-shaped surface spaced around the axial direction, and this arc-shaped surface is a part of a cylinder. The radius of curvature of the curved surface in the cross-sectional direction of the arc-shaped surface may be less than or equal to the radius of curvature of the tuyere avoiding section 2801. The inner contour of the tuyere avoiding section 2801 is the radius of curvature of the cylindrical surface. The cylindrical surface is tangent to the arc-shaped surface on the outer contour of the nozzle avoidance section 261 to form a contact surface. Between two adjacent contact surfaces is a non-contact surface. The non-contact surface and the inner contour of the nozzle avoidance section 2801 A wind space is formed between.

[0092] In an embodiment of the present invention, four, six or more nozzles 260 may be provided.

[0093] In an embodiment of the present invention, the material conveyed by the feeding system 151 is a thermoplastic solid material, such as one or more of metal powder, ceramic particles, glass powder, and plastic particles.

[0094] In an embodiment of the present invention, the cylinder 220 is moved in the axial direction inside the mounting seat 210 in a pneumatic or hydraulic manner. The invention preferably adopts pneumatic means. Of course, it can also be driven by fluid powder or fluid particles. More expansively speaking, the cylinder 220 can also be driven by electromagnetic force or mechanical force.

[0095] In order to achieve a better air-sealing effect: an annular air chamber 253 is provided on the inner side wall of the inner hole, the annular air chamber 253 surrounds the cylinder 220, the annular air chamber 253 and a pressurized gas channel 2531 Connected, the pressure gas channel 2531 is connected to the outside.

[0096] The present invention also provides a control system, including a control circuit 170; a temperature control system that is electrically connected to the control circuit 170; a pressure sensor 161 that is electrically connected to the control circuit 170; a flow sensor 162, The flow sensor 162 is electrically connected to the control circuit 170; the driving system 110 is electrically connected to the control circuit 170, wherein the temperature control system controls the melting state of the material through feedback adjustment, the pressure sensors 161, The flow sensor 162 monitors the pressure and flow parameters of the molten material at the outlet of the three-stage hot runner 211 and transmits it back to the control circuit 170. The control circuit 170 feedbacks and adjusts the power output parameters of the drive system 110 according to the pressure and flow parameters to make the molten material from The actual flow rate when the nozzle 260 flows out is within a preset flow threshold range; a nozzle valve control system 140 is also included. The nozzle valve control system 140 includes a gas source, which passes gas into the second fluid chamber 252 and the first fluid chamber 251 under the control of the control circuit 170. It also includes a pressure measuring device, which is used to measure the gas pressure of the second fluid chamber 252 and the first fluid chamber 251; the pressure measuring device is connected to the control circuit 170, and the control circuit 170 The parameter feedback returned by the measuring device controls the pressure values ​​of the second fluid chamber 252 and the first fluid chamber 251, so as to realize the jacking or retracting state of the cylinder 220 and the nozzle 260. It also includes a signal trigger module, which sends a trigger signal to the control circuit 170 under the trigger of the 3D printing program; the control circuit 170 sends a control signal to the air source according to the trigger signal to specifically control the opening of the second vent pipe Or close.

[0097] As an embodiment of the present invention, this embodiment achieves the air-sealing function at the same time, prevents the material from flowing out of the gap between the cylinder 220 and the inner hole, and also realizes the control of the movement state of the cylinder 220. Two functions, the specific solutions are as follows: at any time, in order to achieve airtightness, one of the first fluid chamber 251 and the second fluid chamber 252 needs to be fed with pressure gas, and the pressure must be higher than that of the molten material in the discharge channel 240 In order to achieve the driving effect, the pressure difference between the two fluid chambers can be controlled.

[0098] Introducing gas into the first fluid chamber 251 is the best solution. The gas is distributed through the gap between the inner hole and the cylinder 220, and the gas does not pollute the printing material. The introduction of liquid into the first fluid chamber 251 and the second fluid chamber 252 may cause material contamination. The introduction of fluid powder into the first fluid chamber 251 and the second fluid chamber 252 may cause the cylinder 220 and the mounting seat 210 The gap between the inner holes is blocked, and the flowable particles are passed through. By controlling the particle size of the particles, it can not only play a role in force transmission, but also avoid contaminants or cause clogging. However, fluid particles are not convenient for force transmission. , And it is inconvenient to use a valve to cut off the power. Therefore, the present invention preferentially uses gas as the power, and the pneumatic method is the most preferred method.

[0099] Of course, there is another embodiment of the present invention: gas is introduced into the first fluid chamber 251, and liquid or gas or fluid particles or powder is introduced into the second fluid chamber 252. The pressure in the first fluid chamber 251 is always Higher than the pressure of the molten material in the discharge channel 240, since the first fluid chamber 251 is closer to the barrel inlet and the limit through groove 2402, the liquid in the second fluid chamber 252 is not easy (such as liquid metal). It is easy to enter the discharge channel 240.

[0100] For a 3D print head with a nozzle, a bevel 2602 is also provided at the intersection between the nozzle sealing section and the nozzle protrusion section, which is convenient for installation and disassembly with a standard wrench.

[0101] The present invention also provides a 3D printer, including a frame, and at least one print head for 3D printing as described above is provided on the frame. It also includes a driving system 110 for driving the 3D printing print head to accurately move to any point in the three-dimensional space.

[0102] The present invention also provides a printing method, including the step of performing additive manufacturing using the print head for 3D printing as described above.

[0103] The working principle of the present invention: various industrial materials are blown into the inlet through the pneumatic feeding system, the materials are brought into the first-level hot runner by the first-stage screw 1201, and the materials are gradually melted under the heating action of the electric heating device 130 (the materials are moving The melting is completed before the end of the primary hot runner), the material is still squeezed in the primary hot runner; the melted material enters the secondary hot runner, the molten material continues to be heated, if there is still unmelted material in the molten state The material can also be melted in the secondary hot runner; the material flows from the secondary hot runner into the tertiary hot runner 211, and is divided into the multiple cylinder inlets 2401, the discharge channel 240, and finally from the nozzle The hole 2631 ejected. When the outer contour of the product needs to be printed accurately, the small-diameter nozzle 260 is controlled to be opened. When the internal filling of the printed product is required, the large-diameter nozzle 260 is used, or multiple nozzles 260 are controlled to be opened simultaneously to achieve multi-channel parallelism. Send out materials to further speed up printing. The present invention can also be equipped with a tuyere structure 280. The tuyere structure 280 can uniformly emit cold air (or room temperature wind) around the newly printed material, avoid cooling other materials that have been cooled to an appropriate degree, and can enhance the wind power. The wind is ring-shaped, and the material is evenly stressed and will not cause the material to be blown away from the established position. When printing large-scale products, the nozzle structure 280 can also be used to blow hot air. The ring-shaped hot air blows out also preheat the material that has been cooled in the upper layer at the next point the print head will reach. A small part of the ring-shaped hot air Although the heat will be transferred to the newly ejected printing material, it is only a small part. Moreover, the final temperature of the material can be maintained by reducing the temperature of the printing material flowing from the nozzle hole 2631 and compensated by the heat of the annular hot air. Within the preset range, in this way, blowing the circular hot air not only has no side effects, but also has unexpected effects. In addition, the flow rate of the print head can be adjusted indirectly by adjusting the decelerating motor to adjust the output intensity of the extruder, selecting nozzles 260 of different calibers, controlling the distance between the inner wall of the cylinder 220 and the lower end of the valve needle 230, and also adjusting the pneumatic feeding system The feed speed is further adjusted, and the output flow of the print head can be flexibly adjusted with different levels of adjustment. An electric heating device 130 is provided outside the casing 180 and the mounting seat 210 to heat and melt the material and heat preservation. It can also adjust the calorific value to achieve sufficient heating, melting and heat preservation effects to adapt to different types Of materials. The material will also generate gas in the hot runner of the extruder. The gas can be discharged from the micro-holes at the intersection of the secondary hot runner and the tertiary hot runner, and the discharged trace material is brought back to extrude by the primary screw 1201. Machine to avoid material loss. The height of the nozzle 260 in the working state is lower than that of other non-working nozzles 260, so as to prevent other non-working nozzles 260 from causing interference on the printed product. The pneumatic feeding system of the present invention also has the function of drying and preheating materials. In this way, a drying device or a preheating device is provided in the pneumatic feeding system to prevent wet materials from being blown into the extruder by wind internal.

[0104] Due to the three-level change of the helix angle, the material is difficult to move in the opposite direction, the material extrusion efficiency is high, and the output flow is stable and reliable. When the air pressure of the second fluid chamber 252 on the cylinder 220 is lower than the air pressure of the first fluid chamber 251, the cylinder 220 is pushed out under the thrust of the first fluid chamber 251, the discharge channel 240 is opened, and the material Ejected from the nozzle hole 2631; when the second fluid chamber 252 and the first fluid chamber 251 on the cylinder 220 are both filled with gas, and the pressure of the second fluid chamber 252 is higher than the pressure of the first fluid chamber 251, the The cylinder 220 is retracted under the thrust of the second fluid chamber 252, the discharge channel 240 is closed, and the material cannot flow out (spout) from the nozzle hole 2631. The present invention preferably adopts four nozzles 260, and the caliber of each nozzle 260 can be set according to needs (generally, the caliber series of the four nozzles 260 change, such as arithmetic change, equi-ratio change). When a nozzle of a certain caliber is required When the 260 outputs materials, the operating state of a certain cylinder 220 can be controlled by controlling the air source, and then the opening and closing of a certain cylinder 220 can be controlled. Of course, the present invention also supports multiple channels and discharges materials to achieve higher Function.

[0105] For a 3D printing head with a nozzle, the difference from a nozzle without a nozzle is that after the hot material is ejected through the nozzle hole 2631 or when ejected, the outer periphery of the nozzle 260 ejects an annular air flow to resist the rigid The extruded hot material is rapidly cooled, and the airflow area is slightly larger than the annular area of ​​the nozzle 260. The contact area between the airflow and the printing material is much smaller than the contact area directly using a fan or fan for heat dissipation; when heating is required, the outer circumference of the nozzle 260 The edge ejects hot air flow to realize heating and improve the bonding effect of the hot material to be extruded and the printed part. When the telescopic nozzle valve is opened, the air can be discharged; if the telescopic nozzle valve is closed, the air cannot be discharged; when the print head has multiple printing nozzles, the nozzle 260 that is discharging can discharge air at the same time to realize the air discharge and discharging. When cooling is required, cool air or airflow at room temperature is blown out to quickly cool the just-extruded material, and it will not cause cooling for other parts. The other parts will not be repeated.

[0106] For a 3D printing head with a tuyere, a multi-way valve structure is also provided inside the tuyere structure 280 to divert the gas. Since the mounting base 210 is in the form of a laminated sheet during manufacture, and the tuyere structure 280 is detachably mounted on the bottom of the mounting base 210. At this time, the difference between the nozzleless 3D printing head and the nozzleless 3D printing head is the nozzle structure 280. You can decide whether to add the nozzle structure 280 according to specific needs. If the nozzleless 3D printing head is used, it needs to cooperate Fan or fan is used for air cooling.

[0107] In summary, with the use of a telescopic nozzle valve, the nozzle 260 can be switched in diameter. When printing fine outer contours, switch to the small-diameter nozzle 260. When printing the internal filling without precision requirements, use a larger diameter than the small-diameter nozzle 260. The caliber nozzle 260 increases the printing speed several times. When printing reaches the blank area, the printing material will cut the material from the end of the nozzle hole 2631 by the mechanical force between the valve needle 230 and the nozzle 260, and keep the internal pressure from changing due to material leakage, and walk through the blank area When reprinting, there is no need to rebuild the pressure to make the printing more stable. When two or more materials are printed on the same printer or two nozzles 260 with different calibers are used, the unused nozzles 260 will automatically leave the plane being printed when they are turned off, and will not affect the printed plane. There are any scratches. The present invention adopts fluid transmission control. The fluid can be gas, liquid, liquid metal, flowable powder, flowable particles, etc. The fluid valve is far away from the high temperature area of ​​printing and can remotely control the opening and closing of multiple nozzles 260.

[0108] In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean specific features described in conjunction with the embodiment or example , Structure, materials or features are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

[0109] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art will not depart from the principle and purpose of the present invention. Under the circumstances, changes, modifications, substitutions and modifications can be made to the above-mentioned embodiments within the scope of the present invention.