Cooling assembly, printing head, and 3D printing device

Abstract

The present application relates to the field of 3D printing, aims to solve the problem of the consumables extrusion speed and the extrusion amount precision of known FDM printing devices being unable to meet the requirements for high-speed printing, and provides a cooling assembly, a printing head, and a 3D printing device. The cooling assembly comprises a first cooling portion and a second cooling portion; the first cooling portion comprises a first cooling channel that allows a cooling medium to circulate, and the first cooling channel is thermally coupled with an extrusion motor of the printing head; the second cooling portion comprises a second cooling channel that allows the cooling medium to circulate, and the second cooling portion is thermally coupled with a throat tube of the printing head. The present application can prevent consumables from soften prematurely, ensures accurate and powerful consumables delivery, and meets the requirement of high extrusion speed required for high speed printing, while guaranteeing the accurate control over the extrusion amount of consumables.

Description

Cooling components, print heads and 3D printing equipment Technical Field

[0001] The present application relates to the field of 3D printing, and more specifically, to a cooling assembly, a print head, and a 3D printing device. Background Art

[0002] 3D printing equipment based on Fused Deposition Modeling (FDM) technology is commonly used for printing thermoplastic materials such as PLA, ABS, TPU, and PETG.

[0003] In the known 3D printing equipment based on FDM technology, the extrusion speed and extrusion volume accuracy of the consumables are difficult to meet the requirements of increasingly higher printing speeds.

[0004] Summary of the Invention

[0005] The present application provides a cooling assembly, a print head and a 3D printing device to solve the problem that the extrusion speed and extrusion volume accuracy of the consumables of the known FDM printing device are difficult to meet the requirements of high-speed printing.

[0006] In a first aspect, the present application provides a cooling assembly for a print head of a 3D printing device, the cooling assembly comprising a first cooling part and a second cooling part; the first cooling part comprises a first cooling channel for circulation of a cooling medium, the first cooling channel being thermally coupled to an extrusion motor of the print head; the second cooling part comprises a second cooling channel for circulation of a cooling medium, the second cooling part being thermally coupled to a throat of the print head.

[0007] The cooling assembly in the present application cools the throat and the extrusion motor through the first cooling part and the second cooling part. The cooling of the extrusion motor can reduce the impact of the heat generated by the operation of the extrusion motor on the consumables at the extrusion gear assembly; the cooling of the throat can reduce the heat transferred upstream by the nozzle assembly to the consumables through the throat, reducing the impact of the heat of the nozzle assembly on the consumables at the upstream extrusion gear assembly. Therefore, by cooling the extrusion motor and the throat, the heat that may be transferred to the consumables at the extrusion gear assembly can be taken away, avoiding the consumables from being softened prematurely due to heat at the extrusion gear assembly, thereby ensuring the precise and powerful delivery of the consumables by the extrusion gear assembly, which is suitable for the high extrusion speed requirements of high-speed extrusion scenarios and can still ensure precise control of the extrusion amount of consumables.

[0008] In one possible embodiment, the first cooling portion further includes a first inlet and a first outlet connected to a first cooling channel, and the first cooling channel is configured to at least partially surround the periphery of the extrusion motor, and the cooling medium enters the first cooling channel from the first inlet and flows out from the first outlet.

[0009] In one possible embodiment, the second cooling portion includes a cooling block, the second cooling channel is provided inside the cooling block, the cooling block includes a first pipe for accommodating the throat pipe, and the second cooling channel is configured to at least partially surround an outer circumference of the first pipe;

[0010] The second cooling portion further includes a second inlet and a second outlet communicating with the second cooling channel. The cooling medium enters the second cooling channel from the second inlet and flows out from the second outlet.

[0011] In one possible embodiment, the first cooling part and the second cooling part are connected to each other, and the cooling assembly further includes a connecting channel connecting the first cooling part and the second cooling part. The cooling medium is configured to enter the second cooling channel from the second inlet, flow out from the second outlet, and enter the first cooling channel from the first inlet through the connecting channel and flow out from the first outlet.

[0012] In a possible embodiment, the cooling block further includes a second pipe connected to the first pipe, and a supporting member for supporting the throat is provided in the second pipe.

[0013] In one possible embodiment, the cooling assembly further includes a cooling medium container, a fluid pump and a cold row; the cooling medium container, the fluid pump, the second cooling part, the first cooling part and the cold row are connected in sequence, and the cooling medium container is also connected to the cold row to form a circulation.

[0014] In a possible implementation, the cooling medium is cooling liquid or cooling gas.

[0015] In the second aspect, the present application provides a print head, including an extrusion component, a nozzle component and the aforementioned cooling component; the extrusion component includes an extrusion motor and an extrusion gear set, the extrusion motor is connected to and drives the extrusion gear set to rotate; the nozzle assembly includes a heating element, a throat and a nozzle, the heating element is thermally coupled to the nozzle, and the throat is configured to connect the nozzle and the extrusion component.

[0016] In one possible embodiment, the nozzle includes a spiral flow channel tube and a discharge nozzle, one end of the spiral flow channel tube is connected to the throat and the other end is connected to the discharge nozzle; the heating element is a heating wire that extends spirally along the spiral flow channel tube and is thermally coupled to the spiral flow channel tube.

[0017] In a possible embodiment, the nozzle also includes a plurality of support blocks arranged in sequence along the discharge direction of the nozzle, and the plurality of support blocks and the support blocks and the second cooling part are fixedly connected by connecting parts; the spiral flow channel tube is supported on the plurality of support blocks respectively; a temperature sensor is provided at each support block, and the temperature sensors correspond to different positions of the spiral flow channel tube respectively, and are used to detect the temperature at different positions of the spiral flow channel tube, and the temperature is used to control the flow rate of the cooling medium and / or the heating temperature of the heating element.

[0018] In a third aspect, the present application provides a 3D printing device, comprising the aforementioned cooling assembly or the aforementioned print head. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] FIG1 is a schematic structural diagram of a 3D printing device according to an embodiment of the present application;

[0021] FIG2 is a schematic structural diagram of a print head according to an embodiment of the present application;

[0022] FIG3 is an exploded view of the print head of FIG2 ;

[0023] FIG4 is another exploded view of the print head of FIG2 ;

[0024] FIG5 is a cross-sectional view of the print head of FIG2 ;

[0025] FIG6 is a schematic structural diagram of an extrusion motor and an extrusion gear assembly according to an embodiment of the present application;

[0026] FIG7 is an exploded view of the extrusion motor and extrusion gear assembly of FIG6 ;

[0027] FIG8 is a schematic structural diagram of a liquid cooling block according to an embodiment of the present application;

[0028] FIG9 is a three-dimensional schematic diagram of the connection structure between the liquid cooling block and another nozzle assembly according to an embodiment of the present application;

[0029] FIG10 is a front view of FIG9;

[0030] FIG11 is a block diagram of a cooling cycle of a print head in an embodiment of the present application;

[0031] FIG12 is a temperature cloud diagram of the print head of the 3D printing device of Comparative Example 1 during printing;

[0032] FIG13 is a temperature cloud diagram of the print head of the 3D printing device according to an embodiment of the present application during printing.

[0033] Description of the main component symbols: 3D printing equipment 100 printing platform 101 print head 10 extrusion assembly 11 cooling assembly 12 extrusion motor 13 extrusion gear assembly 14 nozzle assembly 15, 15a nozzle 16a heating element 16b thermal insulation sleeve 17 throat 18 shell 19 bracket 20 interlayer cooling fan 21 back plate 22 back frame 23 connecting block 24 first cooling part 25 second cooling part 26 cooling ring 27 cooling block 28 box shell 29 first pipeline 30 connecting channel 31 cooling medium container 33 fluid pump 34 cooling radiator 35 cooling radiator fan 36 second pipeline 37 two-stage reduction gear 38 driven gear 39 output end gear 40 filament conveying wheel 41 gearbox bottom shell 42 gearbox front shell 43 gearbox bottom plate 44 gearbox 45 connecting screw46 Quick-release claw 47 Shift lever 48 End nozzle 52 Spiral flow tube 53 Heating wire 54 Support frame 55 First support block 56 Second support block 57 Connector 58 Temperature sensor 59 Third support block 60 First outlet K1 First inlet K2 Second outlet K3 Second inlet K4 Consumable inlet K5 Consumable outlet K6 Ventilation hole K7 Through hole K8 Side opening K9 Top screw hole K10 Consumable supply port K11 Accommodating chamber Q1 Consumable channel S1 First cooling channel T1 Second cooling channel T2 DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be an element centered therein. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be an element centered therein. When an element is considered to be "set on" another element, it may be directly set on the other element or there may also be an element centered therein. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "or / and" as used herein includes any and all combinations of one or more of the relevant listed items.

[0037] Some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0038] Example

[0039] 1 , this embodiment provides a 3D printing device 100 , which may be a 3D printing device based on FDM technology.

[0040] The 3D printing device 100 includes a printing platform 101, a print head 10, and displacement components for the X, Y, and Z directions. Driven by the displacement components, the print head 10 and the printing platform 101 move relative to each other in a controlled manner, thereby printing and forming a printed object on the printing platform 101. The printing platform 101 can be displaced in the Y direction, and the print head 10 can be displaced in the X and Z directions.

[0041] 2 to 5 , in this embodiment, the print head 10 includes an extrusion assembly 11 , a nozzle assembly 15 , and a cooling assembly 12 . The extrusion assembly 11 includes an extrusion motor 13 and an extrusion gear assembly 14 .

[0042] The extrusion motor 13 is connected to the extrusion gear assembly 14, driving the extrusion gear assembly 14 to rotate and transport the filament. The nozzle assembly 15 receives the filament, heats and melts it, and then forces it onto the printing platform 101 to achieve printing. The cooling assembly 12 cools the extrusion assembly and nozzle assembly, making the 3D printing device 100 well-suited for high-speed extrusion and precise transport of filaments.

[0043] 6 and 7 , in this embodiment, the extrusion motor 13 serves as a power source for extruding the consumables. The extrusion motor 13 may be a stepping motor, a brushless DC motor, or other suitable types of motors.

[0044] The extrusion gear assembly 14 includes a two-stage reduction gear 38 and a driven gear 39. The output shaft of the extrusion motor 13 is connected to the input end of the two-stage reduction gear 38. The driven gear 39 and the output end gear 40 of the two-stage reduction gear 38 are meshed, and the number of teeth is equal so that the two have the same rotational speed. The driven gear 39 and the output end gear 40 are respectively connected to a consumables conveying wheel 41. The two consumables conveying wheels 41 are spaced apart from each other, and the gap between the two consumables conveying wheels 41 is used to allow the consumables to pass through. During transportation, the two consumables conveying wheels 41 sandwich the consumables in the middle, and the outer peripheral surfaces of the two consumables conveying wheels 41 are in contact with the consumables. When the consumables conveying wheels 41 rotate, the consumables are driven by friction to move toward the nozzle assembly 15, thereby realizing the transportation of consumables.

[0045] In other embodiments, the two-stage reduction gear 38 can be replaced by a single-stage reduction gear, a three-stage reduction gear, or a reduction gear of other stages, which is not limited here. The output torque can be improved by the reduction gear.

[0046] In this embodiment, the extrusion gear assembly 14 can be arranged in a gear box 45 surrounded by a gear box bottom shell 42, a gear box front shell 43 and a gear box bottom plate 44, wherein the gear box 45 can be connected to the extrusion motor 13 by connecting screws 46, thereby forming a structure in which the extrusion motor 13 and the gear box 45 are integrated. In this embodiment, the extrusion motor 13 is connected to one side of the extrusion gear assembly 14 in the horizontal direction. The horizontal direction here refers to the fact that the consumables are transported vertically downward, and the corresponding extrusion motor 13 is arranged on one side of the extrusion gear assembly 14 in the horizontal direction (i.e., the horizontal direction).

[0047] Optionally, a consumables supply port K11 may be provided at the consumables input end corresponding to the consumables conveying wheel 41. The consumables supply port K11 may be provided by a quick-release claw 47 engaged with the gearbox bottom shell 42. During use, consumables may enter through the consumables supply port K11 on the quick-release claw 47 and then be discharged from the other side by the consumables conveying wheel 41.

[0048] Optionally, the extrusion gear assembly 14 further includes a shift plate 48 , which is used to adjust the distance between the driven gear 39 and the output end gear 40 to clamp or release the consumables.

[0049] In this embodiment, the torque T of the extrusion motor 13 is proportional to the output current I, where I is the output current and K is the torque constant.

[0050] The torque of the extrusion motor 13 will increase after passing through the extrusion gear assembly 14, and the final force output after the extrusion gear assembly 14 is F = (T*i*μ) / r, where i is the reduction ratio of the two-stage reduction gear 38 of the extrusion gear assembly 14, μ is the transmission efficiency of the extrusion gear assembly 14, and r is the lever arm.

[0051] When extruding filaments, it is necessary to ensure that the output force F is greater than the force Ftot required for extrusion of the filament at a given flow rate, that is, F>Ftot.

[0052] As FDM printing equipment develops towards high speed, the required material extrusion speed is getting higher and higher, the corresponding required force Ftot will increase, and the corresponding force F will also need to be higher and higher.

[0053] In order to increase the force F, a common method is to increase the output current I of the extrusion motor 13. However, the currently commonly used extrusion motor 13 adopts a stepper motor. Due to structural and algorithm limitations, it generates severe heat when the output current I is large. In this embodiment, the heat generated by the extrusion motor 13 will be transferred to the extrusion gear assembly 14, and then transferred to the consumables at the extrusion gear assembly 14, causing the consumables to soften prematurely. The consumables that have softened prematurely at the extrusion gear assembly 14 are difficult to reliably withstand the conveying force transmitted by the consumable conveying wheel 41, limiting the increase in the consumable extrusion speed. In addition, after the consumables are softened, their cross-section cannot maintain consistency in the length direction, resulting in the inability to accurately measure and control the amount of consumables conveyed by the consumable conveying wheel 41, making it difficult to accurately output the required amount of consumables as needed, affecting the printing quality.

[0054] Referring again to Figures 2 to 5, the nozzle assembly 15 includes a nozzle 16a, a heating element 16b, an insulating sleeve 17 and a throat 18. The throat 18 is used to receive the consumables delivered by the extrusion gear assembly 14. The received consumables pass through the nozzle 16a and are heated and melted by the heating element 16b, and then extruded onto the printing platform 101 (see Figure 1) to be cooled and formed. The insulating sleeve 17 is sleeved on the outer periphery of the nozzle 16a and the heating element 16b to reduce heat loss at the nozzle 16a and ensure that the consumables at the nozzle 16a reach the required heating temperature. In this embodiment, the throat 18 can be made of insulating material to reduce the heat conduction from the nozzle 16a to the upstream of the consumables.

[0055] The cooling assembly 12 provided in this embodiment includes a first cooling portion 25 and a second cooling portion 26. The first cooling portion includes a first cooling channel for circulating a cooling medium, and the second cooling portion includes a second cooling channel for circulating a cooling medium. The first cooling channel is thermally coupled to the extrusion motor 13 to cool the extrusion motor 13. The second cooling channel is thermally coupled to the throat 18 to cool the throat 18.

[0056] The cooling medium may be a gas refrigerant, a liquid refrigerant, or a solid refrigerant. The gas refrigerant may be air, for example; the liquid refrigerant may be water, salt water, for example; and the solid refrigerant may be ice, dry ice, for example.

[0057] The nozzle assembly 15 and the extrusion motor 13 are cooled by the first cooling part 25 and the second cooling part 26. The cooling of the extrusion motor 13 can reduce the effect of the heat generated by the operation of the extrusion motor 13 on the consumables at the extrusion gear assembly 14; the cooling of the throat 18 can reduce the heat conducted upstream by the nozzle assembly 15 to the consumables through the throat 18, thereby reducing the effect of the heat of the nozzle assembly 15 on the consumables at the upstream extrusion gear assembly 14. Therefore, by cooling the extrusion motor 13 and the throat 18, the heat that may be transferred to the consumables at the extrusion gear assembly 14 can be taken away, and the consumables are prevented from being softened prematurely due to heat at the extrusion gear assembly 14, thereby ensuring that the extrusion gear assembly 14 can accurately and powerfully convey the consumables, which is suitable for the high extrusion speed requirements of high-speed extrusion scenarios and can still ensure accurate control of the extrusion amount of consumables.

[0058] In this embodiment, the first cooling part 25 includes a cooling ring 27, and the second cooling part 26 includes a cooling block 28. The cooling ring 27 at least partially surrounds the outer periphery of the extrusion motor 13 and is thermally coupled with the extrusion motor 13. The connection method of the cooling ring 27 and the extrusion motor 13 can be set as needed, such as by screw connection, etc., which is not limited here. The contact surface between the cooling ring 27 and the extrusion motor 13 can be filled with thermal gaskets, thermal grease, etc. to reduce the contact thermal resistance. The heat generated by iron loss, copper loss, etc. during the operation of the extrusion motor 13 can be conducted to the cooling ring 27, and then carried away by the cooling medium (such as water) flowing in the cooling ring 27. The interior of the cooling ring 27 can adopt a hollow structure, or a flow channel can be provided inside to increase the heat exchange capacity.

[0059] The cooling block 28 is connected between the throat 18 and the extrusion gear assembly 14 to prevent the throat 18 from transferring heat to the extrusion gear assembly 14. The second cooling channel is arranged inside the cooling block. The cooling block 28 includes a box shell 29 and a first pipe 30; the box shell 29 defines a accommodating chamber Q1 for accommodating coolant and serving as a second cooling channel. The first pipe 30 is arranged in the accommodating chamber Q1, and the first pipe 30 defines the consumable channel S1. The box shell 29 is also provided with a consumable inlet K5 and a consumable outlet K6 respectively connected to the two ends of the consumable channel S1. The consumable inlet K5 is used to receive the consumables supplied by the extrusion gear assembly 14 driven by the extrusion motor 13, and the consumable outlet K6 is used to accommodate and connect the throat 18 to supply consumables to the nozzle assembly 15. The second cooling channel is at least partially arranged around the outer periphery of the first pipe to achieve cooling of the first pipe.

[0060] In this embodiment, optionally, the first cooling portion and the second cooling portion are interconnected, that is, the first cooling channel and the second cooling channel are interconnected, and the cooling media therein can flow in series or in parallel.

[0061] For example, the cooling assembly 12 also includes a connecting channel 31, which connects the accommodating chamber Q1 and the cooling ring 27 to achieve centralized combined cooling of the cooling ring 27 and the cooling block 28. By arranging the cooling block 28 between the throat 18 and the extrusion gear assembly 14, the heat from the nozzle assembly 15 that requires high-temperature heating can be blocked from being conducted to the extrusion gear assembly 14, thereby preventing the consumables at the extrusion gear assembly 14 from being softened by heat in advance and affecting the efficiency and accuracy of the extrusion gear assembly 14 in conveying the consumables. At the same time, the cooling of the cooling block 28 can also take away the heat from the extrusion gear assembly 14 and the consumables at the extrusion gear assembly 14, thereby preventing the consumables at the extrusion gear assembly 14 from being softened in advance and affecting the extrusion speed and extrusion amount accuracy of the consumables. Optionally, the cooling block 28 can be made of copper or aluminum alloy.

[0062] The cooling ring 27 has a first outlet K1 and a first inlet K2. The housing 29 has a second outlet K3 and a second inlet K4, each connected to the second cooling channel T2. A connecting channel 31 connects the first inlet K2 and the second outlet K3. The second inlet K4 and the first outlet K1 serve as inlets and outlets for external cooling medium. Thus, the external cooling medium enters through the second inlet K4, passes through the second cooling channel T2 of the cooling block 28 and the connecting channel 31, and enters the first cooling channel T1 of the cooling ring 27. It then exits through the first outlet K1 of the cooling ring 27 to remove heat.

[0063] Similarly, in other embodiments, the connecting channel 31 may also be configured to communicate with the first outlet K1 and the second inlet K4 , and the first inlet K2 and the second outlet K3 serve as inlets and outlets of the external cooling medium, respectively.

[0064] 8 , optionally, the outer periphery of the first pipe 30 is spaced from the inner periphery of the accommodating cavity Q1 so that the cooling medium contained in the accommodating cavity Q1 can surround the outer periphery of the first pipe 30 , ensuring that the first pipe 30 is evenly cooled circumferentially and has a better cooling effect.

[0065] The cooling medium channel between the cooling ring 27 and the cooling block 28 in this embodiment is connected in series, which can greatly improve the space utilization of the print head, facilitate miniaturized design, and has excellent heat dissipation effect, which can greatly increase the material extrusion speed to increase the printing speed.

[0066] In other embodiments, the cooling ring 27 and the cooling block 28 may also be connected in parallel.

[0067] In this embodiment, the extrusion gear assembly 14, the cooling block 28, and the nozzle assembly 15 are arranged in sequence from top to bottom, and the consumables output port at the lower end of the extrusion gear assembly 14 corresponds to the consumables inlet K5 connected to the cooling block 28. One end of the throat pipe 18 is inserted into and matched with the consumables outlet K6, and the other end is connected to the nozzle 16a. In order to tighten the throat pipe 18, in this embodiment, the cooling block 28 is also provided with a second pipe 37 connected to the first pipe 30, and a supporting member (not shown in the figure) that supports the throat pipe can be provided in the second pipe 37. For example, the cooling block 28 can be provided with a second pipe 37 connected between the box shell 29 and the first pipe 30. The second pipe 37 is provided with a top screw hole K10 that runs through the second pipe 37 from the surface of the box shell 29 and passes through to the consumables outlet K6, for screwing in a supporting member (such as a tightening screw) to lock the throat pipe 18 inserted into the consumables outlet K6.

[0068] This embodiment also provides another nozzle assembly 15a. Referring to Figures 9 and 10, in the nozzle assembly 15a, the nozzle is configured to include a spiral flow channel tube 53 and a terminal nozzle 52. One end of the spiral flow channel tube 53 is connected to the consumable outlet K6 through the throat 18, and the other end is connected to the terminal nozzle 52. The heating element of the nozzle assembly 15a is a heating wire 54 that extends spirally around the spiral flow channel tube 53. The spiral flow channel tube 53 and the heating wire 54 of the nozzle assembly 15a can also be covered with a heat insulation sleeve (not shown in Figures 9 and 10).

[0069] One of the core challenges of high-speed printing is high-speed or high-flow extrusion of filaments. High-flow extrusion requires more heat per unit time. If the heat exchange rate is insufficient, the filament will not melt quickly, resulting in a "hot outside, cold inside" phenomenon. As the temperature decreases after heating, filaments with non-Newtonian fluid properties will exhibit increased dynamic viscosity, making them difficult to extrude through the extruder.

[0070] Some known technologies increase the heating area and thus the heating capacity by directly extending the length of the heating tube to accommodate higher filament extrusion speeds. However, this reduces the space utilization of the 3D printing equipment in the direction of gravity and results in an increasingly larger volume at the same printing size.

[0071] In the 3D printing device 100 using the nozzle assembly 15a shown in Figures 9 and 10, the consumables are squeezed into the consumables inlet K5, pass through the cooling block 28 and the throat 18, enter the spiral flow tube 53, and are heated by the spirally extending heating wire 54, and finally extruded through the terminal nozzle 52. Heat is generated by the heating wire 54 wrapped around the spiral flow tube 53 and transferred to the spiral flow tube 53. The spiral flow tube 53 has a spiral flow channel inside, and the consumables are heated by convection, conduction, and other methods inside the spiral flow channel. Because the heating area of ​​the spiral flow channel is significantly larger than that of the straight flow channel, it can provide more heat per unit time, which is more conducive to the high-flow extrusion of consumables.

[0072] The heat at the spiral flow channel 53 is insulated by the throat 18 and finally introduced into the cooling block 28, and is taken away by the cooling medium (such as water) inside the cooling block 28, thereby reducing the thermal impact on upstream consumables.

[0073] Optionally, the spiral flow conduit 53 can be supported and connected by a support frame 55. For example, in this embodiment, the support frame 55 includes a plurality of support blocks that are spaced apart and arranged between the cooling block 28 and the terminal nozzle 52 and are sleeved on the outside of the spiral flow conduit 53. For example, the plurality of support blocks are respectively a first support block 56, a second support block 57 and a third support block 60. The first support block 56 is fixedly connected to the cooling block 28 by a connecting member 58 (such as a reinforcing screw), the second support block 57 is fixedly connected to the first support block 56 by a connecting member 58, and the third support block 60 is fixedly connected to the second support block 57 by a connecting member 58. The spiral flow conduit 53 is fixedly supported on the first support block 56, the second support block 57 and the third support block 60 at the connection point to ensure that the spiral flow conduit 53 is reliably supported. For example, each support block can be set to a ring shape, and the spiral flow conduit 53 fits into the inner hole of the ring shape. The terminal nozzle 52 is fixedly connected to the second support block 57.

[0074] Heat from the spiral flow channel 53 is conducted to the first support block 56, the second support block 57, and the third support block 60. Therefore, temperature sensors 59 can be placed on the first support block 56, the second support block 57, and the third support block 60 to detect the temperature. The detected temperature is reported to the processor for PID adjustment.

[0075] In this embodiment, optionally, the temperature sensor 59 may use NTC, platinum resistance, etc., and the first support block 56, the second support block 57 and the third support block 60 may use high-strength and high-thermal-conductivity metals such as aluminum alloy.

[0076] The spiral flow tube 53 can be manufactured using metal 3D printing or coiling methods. It doesn't have to be a standard spiral tube; other curved shapes are possible, and there's no length restriction. The spiral flow tube 53 can also be used only in a portion of the heating section. It can be connected to the first, second, and third support blocks 56, 57, and 60 using a press-fit or threaded connection. External threads connect the throat 18 and the terminal nozzle 52 at both ends. Highly thermally conductive materials such as brass and aluminum alloy can be used for the spiral flow tube 53 to ensure a more uniform temperature.

[0077] The heating wire 54 can be a resistance wire made of common materials such as nickel-chromium, iron-chromium-aluminum, nickel-chromium-iron, etc.

[0078] The throat 18 can be made of titanium alloy or a copper alloy-titanium alloy-copper alloy Chimaera-type structure. In this embodiment, the 3D printing device 100 optionally further includes a housing 19, a bracket 20, and an interlayer cooling fan 21. The housing 19 has a lateral opening K9; the bracket 20 is connected to the lateral opening K9. The bracket 20 includes a back plate 22 and a back frame 23, which is connected to the upper portion of the back plate 22 and recessed into the interior of the housing 19. A ventilation hole K7 is provided on the side of the housing 19 facing away from the bracket 20. The interlayer cooling fan 21 is located between the housing 19 and the back plate 22, promoting cooling and forming of the filament during the printing process through air cooling. A cooling block 28 is sandwiched between the interlayer cooling fan 21 and the back plate 22. The extrusion gear assembly 14 is located within the back frame 23 and supported on the cooling block 28 by a connecting block 24. The connecting block 24 has a through hole K8 for allowing the filament to pass through and enter the filament channel S1.

[0079] Referring to Figure 11, the cooling assembly 12 of this embodiment also includes a cooling medium container 33, a fluid pump 34, a cold row 35 and a cold row fan 36. Among them, the cooling medium container 33, the fluid pump 34, the cooling block 28, the cooling ring 27, and the cold row 35 are connected end to end in sequence to form a cooling cycle, which is used to take away the heat generated by the extrusion motor 13 and the heat transferred from the throat 18. The cold row fan 36 corresponds to the cold row 35 and is used to air-cool the cold row 35. It should be noted that the cooling block 28 and the cooling ring 27 in Figure 11 are simplified as two different heat sources. In this cooling cycle, the fluid pump 34 provides power for the circulation of the cooling medium (such as water), and the cooling medium flows through the cooling block 28 and the cooling ring 27 to take away the heat, and is air-cooled and dissipated at the cold row 35 through the cold row fan 36. The fluid pump 34 can be a DDC pump, a D5 pump or an ordinary centrifugal pump. The structural shape of the cooling block 28 and the cooling ring 27 is not limited. Aluminum alloy structure can be used to reduce the weight of the extruder, and a flow channel can be opened inside. The selection of the cold row 35, the cooling medium container 33, etc. is designed according to the actual needs of the product. The components in the cooling cycle can be connected by pipes made of materials such as silicone, PVC, and PU. There is no limit on the size of the pipe. For example, a pipe with an outer diameter of 6mm and an inner diameter of 4mm or a pipe with an outer diameter of 4mm and an inner diameter of 2-2.5m can be used. The connection between pipes can be a quick plug, quick twist or pagoda structure, which is not limited here.

[0080] This embodiment also provides a 3D printing method, which includes:

[0081] A cooling block 28 is provided between the extrusion gear assembly 14 of the 3D printing device 100 and the throat 18 of the nozzle assembly 15. A cooling ring 27 is provided on the extrusion motor 13. The cooling block 28 and the cooling ring 27 are connected to each other through a liquid channel. A consumable channel S1 is provided on the cooling block 28.

[0082] The extrusion motor 13 of the 3D printing device 100 drives the extrusion gear assembly 14 to rotate to convey the consumables. The consumables conveyed by the extrusion gear assembly 14 pass through the consumable channel S1 of the cooling block 28 and then enter the nozzle assembly 15 through the throat 18. The consumables are ejected from the nozzle assembly 15 to realize extrusion printing.

[0083] During extrusion printing, the cooling block 28 and the cooling ring 27 are liquid-cooled to remove the heat transferred from the nozzle assembly 15 through the throat 18 and the heat generated by the extrusion motor 13 during operation, so as to control the temperature of the filament at the extrusion gear assembly 14 below the set value;

[0084] By controlling the temperature of the consumable material at the extrusion gear assembly 14 to be below a set value, the consumable material passing through the extrusion gear assembly 14 will not be melted or softened prematurely.

[0085] Figure 12 shows a temperature cloud diagram of the print head of a pair of proportional 3D printing devices during printing. The 3D printing device uses a radiator + fan structure to achieve heat dissipation. When the extrusion motor heat is 13.5W (output current is 1.2A) and the heating nozzle temperature is 230°C, the radiator temperature is 57°C, the temperature at the extrusion motor is as high as 77°C, and the extrusion gear assembly is affected by heat conduction and the temperature is greater than 65°C. Commonly used materials such as PLA have a softening temperature of around 50°C. Obviously, for some consumables with a lower softening temperature (such as PLA consumables), this embodiment is easily affected by the heat conducted by the extrusion motor when passing through the extrusion gear assembly, causing the consumables to soften, thereby affecting the extrusion speed and extrusion volume accuracy, making it difficult to apply to high-speed extrusion scenarios.

[0086] Figure 13 shows a temperature cloud diagram of the print head 10 of the 3D printing device 100 of this embodiment during printing. The 3D printing device 100 of this embodiment uses the aforementioned cooling block 28 and cooling ring 27 for centralized liquid cooling. When the heat of the extrusion motor 13 is 13.5W (output current is 1.2A), the temperature of the nozzle 16a is 230°C, and the coolant is cooling water with an inlet temperature of 25°C, the temperature of the extrusion motor 13 is less than 29°C, i.e., a temperature rise of 4°C. The temperature of the cooling assembly 12 is close to 25°C. There is room for further improvement in the output current of the extrusion motor 13 and even the extrusion force F, making it well suited for high-speed printing.

[0087] Based on the above description, the cooling assembly 12, print head 10, 3D printing device 100 and 3D printing method in the embodiment of the present application can reduce the temperature at the extrusion gear assembly 14, avoid the premature softening of the consumables due to heat at the extrusion gear assembly 14, thereby ensuring the accurate and powerful delivery of the consumables by the extrusion gear assembly 14, which is suitable for the high extrusion speed requirements of high-speed extrusion scenarios, and can still maintain precise control of the extrusion amount of consumables, which is suitable for the development trend of high-speed printing. In addition, by achieving centralized cooling of the cooling block 28 and the cooling ring 27, the structure is more compact and simple than the known radiator + fan form, and is more conducive to the development of miniaturization of the structure.

[0088] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present application should not depart from the spirit and scope of the technical solutions of the present application.

Claims

1. A cooling assembly for a print head of a 3D printing device, characterized in that: The cooling assembly includes a first cooling portion and a second cooling portion; The first cooling portion includes a first cooling channel for cooling medium to flow, and the first cooling channel is thermally coupled to an extrusion motor of the print head; The second cooling portion includes a second cooling channel for cooling medium to flow through, and the second cooling portion is thermally coupled to the throat of the print head.

2. The cooling assembly according to claim 1, characterized in that: The first cooling portion further includes a first inlet and a first outlet connected to the first cooling channel. The first cooling channel is configured to at least partially surround the outer periphery of the extrusion motor. The cooling medium enters the first cooling channel from the first inlet and flows out from the first outlet.

3. The cooling assembly according to claim 2, characterized in that: The second cooling portion comprises a cooling block, the second cooling channel is arranged inside the cooling block, the cooling block comprises a first pipe for accommodating the throat, and the second cooling channel is configured to at least partially surround the outer periphery of the first pipe; The second cooling portion further includes a second inlet and a second outlet communicating with the second cooling channel, and the cooling medium enters the second cooling channel from the second inlet and flows out from the second outlet.

4. The cooling assembly according to claim 3, characterized in that: The first cooling part and the second cooling part are connected to each other, and the cooling component also includes a connecting channel connecting the first cooling part and the second cooling part. The cooling medium is configured to enter the second cooling channel from the second inlet and flow out from the second outlet, and enter the first cooling channel from the first inlet through the connecting channel and flow out from the first outlet.

5. The cooling assembly according to claim 3, characterized in that: The cooling block further comprises a second pipe connected to the first pipe, wherein a supporting member for supporting the throat is arranged in the second pipe.

6. The cooling assembly according to claim 1, characterized in that: The cooling assembly also includes a cooling medium container, a fluid pump and a cooling row; The cooling medium container, the fluid pump, the second cooling part, the first cooling part and the cold row are connected in sequence, and the cooling medium container is also connected to the cold row to form a cycle.

7. The cooling assembly according to any one of claims 1 to 6, characterized in that: The cooling medium is cooling liquid or cooling gas.

8. A print head, characterized in that: It includes an extrusion assembly, a nozzle assembly and a cooling assembly; The cooling assembly includes a first cooling portion and a second cooling portion; The first cooling portion includes a first cooling channel for cooling medium to flow, and the first cooling channel is thermally coupled to an extrusion motor of the print head; The second cooling portion includes a second cooling channel for cooling medium to flow, and the second cooling portion is thermally coupled to the throat of the print head; The extrusion assembly includes an extrusion motor and an extrusion gear set, and the extrusion motor is connected to and drives the extrusion gear set to rotate; The spray head assembly includes a heater, a throat and a nozzle, wherein the heater is thermally coupled to the nozzle, and the throat is configured to connect the nozzle and the extrusion assembly.

9. The print head according to claim 8, characterized in that: The nozzle comprises a spiral flow channel tube and a discharge nozzle, one end of the spiral flow channel tube is connected to the throat tube, and the other end is connected to the discharge nozzle; The heating element is a heating wire which spirally extends along the spiral flow channel tube and is thermally coupled to the spiral flow channel tube.

10. The print head according to claim 9, characterized in that: The nozzle further comprises a plurality of support blocks sequentially arranged along the discharge direction of the nozzle, wherein the plurality of support blocks and the support blocks and the second cooling part are fixedly connected by connecting members respectively; The spiral flow channel tube is supported by a plurality of the support blocks respectively; A temperature sensor is provided at each of the support blocks, and the temperature sensors correspond to different positions of the spiral flow channel tube respectively, and are used to detect the temperature of different positions of the spiral flow channel tube. The temperature is used to control the flow rate of the cooling medium and / or the heating temperature of the heating element.

11. A 3D printing device, characterized in that: comprising a print head, the print head comprising a cooling assembly; The cooling assembly includes a first cooling portion and a second cooling portion; The first cooling portion includes a first cooling channel for cooling medium to flow, and the first cooling channel is thermally coupled to an extrusion motor of the print head; The second cooling portion includes a second cooling channel for cooling medium to flow through, and the second cooling portion is thermally coupled to the throat of the print head.

12. The 3D printing device according to claim 11, characterized in that: The first cooling portion further includes a first inlet and a first outlet connected to the first cooling channel. The first cooling channel is configured to at least partially surround the outer periphery of the extrusion motor. The cooling medium enters the first cooling channel from the first inlet and flows out from the first outlet.

13. The 3D printing device according to claim 12, characterized in that: The second cooling portion comprises a cooling block, the second cooling channel is arranged inside the cooling block, the cooling block comprises a first pipe for accommodating the throat, and the second cooling channel is configured to at least partially surround the outer periphery of the first pipe; The second cooling portion further includes a second inlet and a second outlet communicating with the second cooling channel, and the cooling medium enters the second cooling channel from the second inlet and flows out from the second outlet.

14. The 3D printing device according to claim 13, characterized in that: The first cooling part and the second cooling part are connected to each other, and the cooling component also includes a connecting channel connecting the first cooling part and the second cooling part. The cooling medium is configured to enter the second cooling channel from the second inlet and flow out from the second outlet, and enter the first cooling channel from the first inlet through the connecting channel and flow out from the first outlet.

15. The 3D printing device according to claim 13, characterized in that: The cooling block further comprises a second pipe connected to the first pipe, wherein a supporting member for supporting the throat is arranged in the second pipe.

16. The 3D printing device according to claim 11, characterized in that: The cooling assembly also includes a cooling medium container, a fluid pump and a cooling row; The cooling medium container, the fluid pump, the second cooling unit, the first cooling unit and the cooling row are connected in sequence The cooling medium container is also connected to the cold row to form a circulation.

17. The 3D printing device according to any one of claims 11 to 16, characterized in that: The cooling medium is cooling liquid or cooling gas.

18. The 3D printing device according to claim 11, characterized in that: The print head also includes an extrusion assembly and a nozzle assembly; The extrusion assembly includes an extrusion motor and an extrusion gear set, and the extrusion motor is connected to and drives the extrusion gear set to rotate; The spray head assembly includes a heater, a throat and a nozzle, wherein the heater is thermally coupled to the nozzle, and the throat is configured to connect the nozzle and the extrusion assembly.

19. The 3D printing device according to claim 18, characterized in that: The nozzle comprises a spiral flow channel tube and a discharge nozzle, one end of the spiral flow channel tube is connected to the throat tube, and the other end is connected to the discharge nozzle; The heating element is a heating wire which spirally extends along the spiral flow channel tube and is thermally coupled to the spiral flow channel tube.

20. The 3D printing device according to claim 19, characterized in that: The nozzle further comprises a plurality of support blocks sequentially arranged along the discharge direction of the nozzle, wherein the plurality of support blocks and the support blocks and the second cooling part are fixedly connected by connecting members respectively; The spiral flow channel tube is supported by a plurality of the support blocks respectively; A temperature sensor is provided at each of the support blocks, and the temperature sensors correspond to different positions of the spiral flow channel tube respectively, and are used to detect the temperature of different positions of the spiral flow channel tube. The temperature is used to control the flow rate of the cooling medium and / or the heating temperature of the heating element.

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