Melt extrusion device, 3D printing robot and 3D printing equipment

Abstract

The present application discloses a melt extrusion device, a 3D printing robot and a 3D printing device, wherein the melt extrusion device includes a feeding system and a print head; the print head includes a valve cavity, a valve core, an extrusion channel, and a nozzle connected to the extrusion channel, and the nozzle includes a tapered extrusion port; the valve core includes an axis body, a flow channel, and a sink groove partially surrounding the axis body; the inlet holes of the flow channel are all located in the sink groove for the fluid material to be filled into the sink groove, and the outlet hole of the flow channel is partially located in the sink groove; when the valve core is in an open state, the flow channel connects the extrusion channel and the tapered extrusion port for the fluid material to flow through the nozzle, and when the valve core is in a closed state, the outlet hole of the flow channel is misaligned with the tapered extrusion port to prevent the fluid material from flowing through the nozzle, and the fluid material is kept between the valve core and the valve cavity. The melt extrusion device, 3D printing robot and 3D printing device provided by the present application can achieve complete closure of the print head and avoid direct mechanical contact with the print head, thereby ensuring printing accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of robots, and in particular to a melt extrusion device, a 3D printing robot and a 3D printing device. Background Art

[0002] At present, 3D printing technology is mainly divided into fused deposition modeling (FDM), liquid photosensitive resin photocuring (SLA or DLP), selective laser sintering (SLS), selective laser melting (SLM) and other technologies. Among them, fused deposition modeling technology is a commonly used technology in 3D printing technology. By controlling the print head, it extrudes molten filamentary materials such as thermoplastics, wax or metal filaments on the printing platform according to the contour and filling trajectory of each preset thickness slice layer of the 3D object, so that the molten material is deposited and solidified, and then the required 3D object is generated layer by layer.

[0003] Generally, when it is necessary to stop delivering molten material to the print head, the print head is usually controlled to deliver or stop delivering molten material by controlling the opening and closing of the valve mechanism. However, it is difficult for the valve mechanism of the ordinary print head nozzle to achieve complete closure of the print head, which will cause leakage of molten material, thereby affecting the printing accuracy. In addition, if the valve mechanism is completely closed, the fluid material inside the valve mechanism will generate pressure due to thermal expansion, which will press the closed valve mechanism to the inner wall of the valve cavity, and produce direct mechanical contact with the print head, which will not only make it impossible to reopen the next time it is used, or require a greater force to force the switch, which will cause mechanical wear of the valve mechanism. After repeated use, the valve mechanism is easy to loosen and thus affect its service life. Long-term use will also cause damage to the print head, thereby affecting the smooth progress of 3D printing operations. Therefore, how to design a valve mechanism that can achieve complete closure of the print head and avoid direct mechanical contact with the print head to ensure printing accuracy is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of the shortcomings of the related technologies mentioned above, the purpose of the present application is to provide a melt extrusion device, a 3D printing robot and a 3D printing equipment, which are used to solve the technical problems in the related technologies that the valve mechanism is difficult to completely close the print head, causing leakage of molten material and resulting in low printing accuracy, and forced closing of the valve mechanism will cause damage to the print head.

[0005] To achieve the above-mentioned purpose and other related purposes, the present application provides a melt extrusion device of a 3D printing robot in a first aspect, comprising: a feeding system, arranged on a mechanical arm of the 3D printing robot, for melting a granular material into a fluid material and pressurizing and outputting it through a feeding channel; a print head, comprising a valve cavity, an extrusion channel connected to the feeding channel, and a nozzle connected to the extrusion channel, wherein the nozzle comprises a tapered extrusion port for printing the fluid material; a valve core, comprising an axis body arranged in the valve cavity, radially penetrating the axis body, a flow channel for docking the extrusion channel, and a sink formed around the axis body; the inlet holes of the flow channel are all located in the sink so that the fluid material from the extrusion channel is filled into the sink, and the outlet hole of the flow channel is partially located in the sink; when the valve core is in an open state, the flow channel connects the extrusion channel and the extrusion port so that the fluid material flows through the nozzle, and when the valve core is in a closed state, the outlet hole of the flow channel is misaligned with the extrusion port to prevent the fluid material from flowing through the nozzle, and the fluid material filled in the sink is held between the valve core and the valve cavity.

[0006] A second aspect of the present application provides a 3D printing robot, wherein the 3D printing robot comprises a melt extrusion device as described in any one of the embodiments provided in the first aspect of the present application.

[0007] The third aspect of the present application provides a 3D printing device, including: a molding chamber, used to provide a closed molding space for 3D printing operations; a printing platform, rotatably arranged in the molding chamber for carrying a molded 3D object; a first robot, arranged on a first side of the printing platform, including a first robot arm that moves on the upper side of the printing platform according to a first motion path, and a print head arranged on the first robot arm for melting powder or granular material and depositing it on the printing platform according to the first printing path to form the 3D object layer by layer; wherein the first robot arm is provided with a melt extrusion device as described in any embodiment of the first aspect of the present application; a second robot, arranged on a second side of the printing platform and at a first preset angle to the first robot, including a second robot arm that moves on the upper side of the printing platform according to a second motion path, and a cutting component arranged on the second robot arm for performing subtractive processing on the 3D object deposited on the printing platform according to a subtractive path.

[0008] To summarize, the melt extrusion device, 3D printing robot and 3D printing equipment provided by the present application, by setting a valve cavity for accommodating a valve core in the print head, and setting a flow channel in the valve core that radially penetrates the valve core shaft body and connects with the extrusion channel, so that the flow channel can realize the open state of the valve core when the extrusion channel and the tapered extrusion port are connected, and can realize the closed state of the valve core when the outlet hole of the flow channel is misaligned with the tapered extrusion port on the print head nozzle, so as to control whether the fluid material can flow through the nozzle on the print head, thereby realizing the normal opening and complete closing of the print head, avoiding leakage of the fluid material, and thus ensuring printing accuracy. By arranging a partially surrounding groove on the shaft body of the valve core, the valve core can fill the groove with fluid material when it is in a closed state and maintain it between the valve core and the valve cavity, so that the valve core is wrapped by the fluid material, and the valve core is placed in a "suspended" state. This can prevent the valve core from being crushed to the inner wall of the valve cavity due to the thermal expansion of the fluid material when it is closed, avoid direct mechanical contact between the valve core and the print head, and avoid damage to the print head, thereby ensuring the smooth progress of the printing operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The specific features of the present application are shown in the attached claims. The features and advantages of the invention involved in the present application can be better understood by referring to the exemplary embodiments and drawings described in detail below. The drawings are briefly described as follows:

[0010] Figure 1 and Figure 2 They are respectively shown as schematic diagrams of the structures of 3D printing devices in different embodiments of the present application.

[0011] Figure 3 It is a schematic diagram of the structure of a molding chamber in one embodiment of the present application.

[0012] Figure 4 Shown is a schematic diagram of zoned temperature control of a printing platform in one embodiment of the present application.

[0013] Figure 5 Shown is a schematic diagram of the structure of the first robot in one embodiment of the present application.

[0014] Figure 6 It is a schematic diagram showing the working area of ​​the molding surface on the printing platform occupied by the second motion path in one embodiment of the present application.

[0015] Figure 7 It is a schematic diagram showing that the first motion path and the second motion path occupy the printing area and the working area of ​​the printing platform respectively in one embodiment of the present application.

[0016] Figure 8 Shown is a schematic structural diagram of a feeding system in one embodiment of the present application.

[0017] Fig. 9 Shown is a schematic diagram of the structure of a print head in one embodiment of the present application.

[0018] Fig.10 Shown is a schematic diagram of the structure of a print head configured with an access device in one embodiment of the present application.

[0019] Fig.11 and Fig.12 They are respectively schematic diagrams of the structure of the valve core at different viewing angles in one embodiment of the present application.

[0020] Fig.13 Shown is a cross-sectional view of a valve core in one embodiment of the present application.

[0021] Fig.14 It is a schematic diagram showing that the valve core is in a closed state in one embodiment of the present application.

[0022] Fig.15 It is a schematic diagram showing the cooperation between the valve core and the actuator in one embodiment of the present application.

[0023] Fig.16 It is a cross-sectional schematic diagram showing a valve core in an open state in a valve cavity in one embodiment of the present application.

[0024] Fig.17 It is a cross-sectional schematic diagram showing a valve core in a closed state in a valve cavity in one embodiment of the present application.

[0025] Fig.18 Shown is a cross-sectional view of a valve core in another embodiment of the present application. DETAILED DESCRIPTION

[0026] The following is an explanation of the implementation of the present application by means of specific embodiments. People familiar with the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification.

[0027] In the following description, reference is sometimes made to the accompanying drawings, which describe several embodiments of the present application. It should be understood that other embodiments may also be used, and that changes in module or unit composition, electrical, and operation may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is limited only by the claims that are published. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0028] It will be understood that, although the terms first, second, etc. may be used in some instances to describe various elements or parameters in this article, these elements or parameters should not be limited by these terms. These terms are only used to distinguish one element or parameter from another element or parameter. For example, the first robot may be referred to as the second robot, and similarly, the second robot may be referred to as the first robot without departing from the scope of the various described embodiments. The first robot and the second robot are both describing a certain robot, but unless the context clearly indicates otherwise, they are not the same robot. The terms "or" and "and / or" used in this article are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. Only when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way, will there be an exception to this definition.

[0029] It will be understood that when a part or element is referred to as being "on" or extending "onto" another element, the element may be directly on or directly extending onto the other element, or intervening elements may also be present. Conversely, when an element is referred to as being "directly on" or "extending directly onto" another element, there are no intervening elements. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0030] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer or region to another element, layer or region as illustrated in the figure. It will be understood that these terms are intended to cover different device orientations other than the orientation depicted in the figure. In this application, the "vertical", "horizontal" and "parallel" are defined as: including the situation of ±10% based on the standard definition. For example, vertical usually refers to an angle of 90° relative to a reference line, but in this application, vertical refers to a situation within 80° to 100°.

[0031] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. When used herein, the singular forms "a", "an", and "the" are intended to also include the plural forms unless the context clearly indicates otherwise. It will also be understood that when used herein, the terms "comprise", "include", "include" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or increase of one or more other features, integers, steps, operations, elements, parts and / or combinations thereof.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It will also be understood that the terms used herein should be interpreted as having the meaning consistent with their meaning in the context of this specification and the relevant field, and should not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0033] Unless otherwise expressly stated, comparative quantitative terms (such as "above" and "below") are intended to encompass the concept of equality. As an example, "above" may not only mean "greater than" in a mathematical sense, but may also mean "equal to".

[0034] In view of the technical problems mentioned in the background technology, the present application discloses a melt extrusion device, a 3D printing robot and a 3D printing equipment. A valve cavity for accommodating a valve core is set in the print head, and a flow channel is set in the valve core which radially penetrates the shaft body of the valve core and connects with the extrusion channel, so that the flow channel can realize the open state of the valve core when the extrusion channel and the tapered extrusion port are connected, and the closed state of the valve core can be realized when the outlet hole of the flow channel is misaligned with the tapered extrusion port on the print head nozzle, so as to control whether the fluid material can flow through the nozzle on the print head, thereby realizing the normal opening and complete closing of the print head, avoiding leakage of the fluid material, and thus ensuring printing accuracy. By arranging a partially surrounding groove on the shaft body of the valve core, the valve core can fill the groove with fluid material when it is in a closed state and maintain it between the valve core and the valve cavity, so that the valve core is wrapped by the fluid material, and the valve core is placed in a "suspended" state. This can prevent the valve core from being crushed to the inner wall of the valve cavity due to the thermal expansion of the fluid material when it is closed, avoid direct mechanical contact between the valve core and the print head, and avoid damage to the print head, thereby ensuring the smooth progress of the printing operation.

[0035] In any embodiment provided in the present application, the 3D object may be a 3D model obtained by stacking 3D printing materials layer by layer using 3D printing technology, which may be, for example, a sculpture of an animation or animal, a building for a company's front desk, or an outdoor art model. The 3D printing technology may be, for example, a fused deposition modeling technology based on fusible granular materials. In this example, the 3D printing material for constructing the 3D object may be, for example, a thermoplastic material. The thermoplastic material may be, for example, a polymer composite printing material containing nylon, paraffin, casting wax, artificial rubber, metal, ceramic, etc., which may be heated to a flowing or semi-fluid state in the form of powder or granular material, and then stacked and cooled layer by layer to form a 3D object.

[0036] In some embodiments, the present application provides a 3D printing device. Figure 1 and Figure 2 , respectively showing the structural schematic diagrams of the 3D printing device in different embodiments of the present application. As shown in the figure, the 3D printing device includes a molding chamber 1, a printing platform 2, a first robot 3, and a second robot 4.

[0037] The following is a detailed description of the 3D printing device of the present application.

[0038] The molding chamber 1 is used to provide a closed molding space for 3D printing operations. It should be understood that the fused deposition modeling printing technology is relatively sensitive to temperature. When the 3D printing material needs to be melted and extruded, it needs to be heated to the melting point to form a semi-fluid state. When the molten 3D printing material is extruded onto the printing platform, it needs to be cooled to a temperature below the melting point so that the printed layer is solidified and formed. Therefore, the molding chamber 1 needs to be set in a closed form to construct a closed internal environment to reduce the impact of the airflow outside the molding chamber on the 3D printing operation, and to make the temperature of the internal environment constant to facilitate temperature control.

[0039] In order to construct a constant temperature environment in the molding chamber, in one embodiment, the molding chamber 1 can be configured as a composite structure with multiple layers of materials. For example, the outer layer in contact with the external environment can be configured as metal or high-strength plastic to provide rigid support for the molding chamber. The inner layer in contact with the internal environment of the 3D printing operation can be configured as a heat-insulating material, such as polyurethane foam, polycarbonate board, aluminum silicate fiber or mineral wool, etc., to reduce heat loss in the internal environment.

[0040] In one embodiment, see Figure 3 Combined with Figure 1 and Figure 2 ,in, Figure 3 The structure diagram of the molding chamber in one embodiment of the present application is shown as follows: Figure 2As shown, the cross-section of the molding chamber 1 in the horizontal direction is a symmetrical hexagonal structure with four obtuse angles and two right angles. Specifically, the six angles located in the hexagonal structure are angle a, angle b, angle c, angle d, angle e, and angle f in the clockwise direction. Among them, the four obtuse angles are angle b, angle c, angle d, and angle e. For the convenience of distinction, angle b, angle c, angle d, and angle e can also be described as the first obtuse angle b, the second obtuse angle c, the third obtuse angle d, and the fourth obtuse angle e, respectively. The two right angles are angle a and angle f. For the convenience of distinction, angle a and angle f are also described as the first right angle a and the second right angle f, respectively. Figure 2 In the example shown, the six corners are all sharp corners. In other examples, in order to avoid bumping into the operator, the six corners may be configured as rounded corners.

[0041] In one embodiment, if Figure 3 As shown, an entrance and exit 13 of the molding chamber 1 is provided on one side of the molding chamber 1, and the width of the entrance and exit 13 is greater than the rotation diameter of the printing platform 2. The rotation diameter can be referred to the description in the subsequent embodiments, which will not be repeated here. The entrance and exit 13 can be used for the entry and exit of operators, and the loading and unloading of various devices, structures, components, and 3D objects in the 3D printing equipment. In order to ensure that the molding chamber 1 can provide a closed internal environment during the 3D printing process, in one implementation, the entrance and exit 13 can be configured as a revolving door, and the revolving door is connected to the molding chamber 1 by a hinge, so that the revolving door can realize the opening and closing of the molding chamber 1 through a rotational motion. Of course, in some other implementations, it can also be configured as a sliding door, an automatic door, etc.

[0042] In one embodiment, if Figure 2 As shown, the first robot 3 is arranged between the first right angle a and the first obtuse angle b in the molding chamber 1, and the second robot 4 is arranged between the second right angle f and the fourth obtuse angle e in the molding chamber 1. In another embodiment, as Figure 1 As shown, the first robot 3 is arranged between the first right angle a and the first obtuse angle b in the molding chamber 1, and the second robot 4 is arranged between the second obtuse angle c and the third obtuse angle d in the molding chamber 1. However, this is not limited to the above, and the first robot 3 and the second robot 4 can also be arranged at other positions in the molding chamber 1, which can be determined according to actual production needs. It should be noted that the molding chamber 1 is configured as follows: Figures 1 to 3The hexagonal structure shown is only a schematic representation. In this example, in order to minimize the area of ​​the molding chamber 1 and reduce the heating range, thereby increasing the speed of heat transfer, which is beneficial to controlling the temperature in the molding chamber, the side length of the hexagonal structure is set according to the width of the first robot 3 and the second robot 4. In certain other examples, the molding chamber 1 can also be set to other shapes besides rectangles and hexagons, such as pentagons, circles, etc., which are determined according to actual production needs, and this application does not impose any restrictions on this.

[0043] In one embodiment, if Figure 3 As shown, a first auxiliary equipment configuration area 11 is provided outside the edge formed between the first obtuse angle b and the second obtuse angle c in the molding chamber 1, and a second auxiliary equipment configuration area 12 is provided outside the edge formed between the third obtuse angle d and the fourth obtuse angle e in the molding chamber 1. The outer edge refers to the external area of ​​the molding chamber corresponding to a certain edge of the hexagonal structure formed by the molding chamber 1. For example, the outer edge formed between the first obtuse angle b and the second obtuse angle c refers to the area outside the molding chamber 1 corresponding to the edge m shared by the first obtuse angle b and the second obtuse angle c. The first auxiliary equipment configuration area 11 is used to configure the first auxiliary equipment, and the second auxiliary equipment configuration area 12 is used to configure the second auxiliary equipment. It should be noted that the first auxiliary equipment configuration area 11 or the second auxiliary equipment configuration area 12 can be configured separately or together. Of course, the first auxiliary equipment configuration area 11 or the second auxiliary equipment configuration area 12 may not be provided. It is determined according to the actual needs of configuring the first auxiliary equipment and the second auxiliary equipment, and this application does not impose any restrictions on this.

[0044] In one embodiment, the first auxiliary device or the second auxiliary device can be configured as a power supply device, such as a generator, to provide a stable power supply for the 3D printing device. In another embodiment, it can also be configured as an imaging device for real-time observation of the 3D printing process outside the molding room to ensure the normal operation of the first robot and the second robot, but it is not limited to this, and its specific configuration is determined according to actual production needs.

[0045] In some embodiments, the 3D object is difficult to maintain constant internal temperature and external atmosphere temperature between stacked layers due to its large size, which causes different thermal stresses on the stacked layers, leading to stress accumulation inside the 3D object, and then uneven shrinkage, causing the 3D object to warp, deform, and other problems. In view of this, the molding chamber 1 is equipped with an atmosphere temperature control system, and the temperature control system can be configured to include a hot and cold air circulation convection device, which is used to keep the temperature of the stacked layers of the 3D object constant, thereby avoiding problems such as warping and deformation of the 3D object.

[0046] Of course, in some other embodiments, the molding chamber 1 may be equipped with an air conditioner and a fan to control the temperature of the internal environment of the molding chamber within a suitable range. A dehumidifier and other equipment may also be configured to adjust the humidity of the internal environment to ensure that the various devices, structures, and components in the 3D printing device can work normally, and at the same time ensure that the 3D printing materials can be in an ideal state, thereby ensuring that the 3D printing operation can proceed smoothly. In addition, an air purification system may be configured in the molding chamber 1 to promptly remove the gas and particles generated during the printing process, thereby ensuring the cleanliness of the internal environment. Those skilled in the art may select a specific configuration based on the actual design under the guidance of this application.

[0047] In one embodiment, the printing platform 2 is rotatably disposed in the molding chamber 1 for supporting the molded 3D object. Figure 3 In the example shown, the printing platform 2 is configured as a circular platform, and the diameter of the circular platform ranges from 2800mm to 3600mm, for example, approximately 2800mm, 2900mm, 3000mm, 3100mm, 3200mm, 3300mm, 3400mm, 3500mm, or 3600mm. In some other examples, the printing platform 2 can also be configured as a shape other than a circle, such as a rectangle or a hexagon. In this case, the printing platform 2 has a rotation diameter and a rotation center. The rotation diameter refers to the diameter of the circular range occupied by the printing platform 2 when it rotates, and the rotation center refers to the center of the circular range occupied by the printing platform 2 when it rotates. It should be understood that when the printing platform is configured as a circular platform, the rotation diameter and the rotation center are the diameter and center of the printing platform, and the rotation diameter and the rotation center are not repeated in the subsequent embodiments.

[0048] In one embodiment, in order to realize the rotation of the printing platform 2, a rotating shaft (not shown) is provided on the printing platform 2, and a grating encoder and a servo motor are provided on the rotating shaft. The grating encoder is used to provide measurement and feedback of the rotation angle of the printing platform 2. The servo motor is used to provide rotational power for the rotating shaft. In some examples, the servo motor can drive the rotating shaft to rotate clockwise and counterclockwise. In some embodiments, the servo motor can also be replaced by a hydraulic motor.

[0049] In one embodiment, the grating encoder includes a grating encoder housing, a grating encoder disk and a reading head. The grating encoder housing is arranged around the rotating shaft and accommodates the grating encoder disk and the reading head. The grating encoder disk has grating strips. When the rotating shaft rotates, the grating strips on the grating encoder disk will be blocked and generate corresponding optical signals. The reading head may include an optical measuring device such as a camera, and obtains the rotation information of the rotating shaft by interpreting the generated optical signal, and feeds the information back to a control device, thereby realizing real-time control of the rotation of the printing platform.

[0050] In one embodiment, a brake locator is provided on the printing platform 2, and the brake locator is used to stop the rotational movement of the printing platform 2. At the same time, it can also prevent the printing platform 2 from rotating due to external forces when the movement stops, thereby further ensuring the printing accuracy. In one implementation, the brake locator can be configured to include a brake driver and a locking pin, and the brake driver controls the movement of the locking pin to lock the locking pin on the printing platform, thereby stopping the rotational movement of the printing platform. The brake driver can be, for example, a motor.

[0051] In one embodiment, a temperature control component for controlling the temperature of the molding surface is provided on the printing platform 2. The molding surface refers to the surface where the printing platform contacts the printing layer of the 3D object. In one example, the temperature control component includes a temperature sensor, a temperature controller, a heating element, and a cooling element. The temperature sensor is used to monitor the temperature of the molding surface in real time. The heating element is used to provide heat energy to increase the temperature of the molding surface. It can be, for example, a resistance heater, a heating winding, and a heating cable. The cooling element is used to provide a cooling effect to reduce the temperature of the molding surface. It can be, for example, a fan, a cooling water circulation system, and a refrigerant circulation system. Specifically, when the temperature sensor detects that the temperature of the molding surface is lower than a threshold, the temperature controller controls the heating element to operate until the temperature of the molding surface reaches the threshold. When the temperature sensor detects that the temperature of the molding surface is higher than the threshold, the temperature controller controls the cooling element to operate until the temperature of the molding surface reaches the threshold. The threshold is a temperature value or temperature range pre-set by the operator that is lower than the melting point of the 3D printing material, so that the printing layer can be solidified when deposited on the molding surface.

[0052] In one embodiment, the printing platform 2 can perform zone temperature control on the molding surface. For details, please refer to Figure 4 , which is a schematic diagram showing the temperature control of the printing platform in a zone in one embodiment of the present application. Figure 4 As shown, the printing platform 2 can be divided into eight temperature zones. Figure 4One of the temperature zones is indicated by the letter t, and each temperature zone has an independent temperature control component to achieve independent temperature control of each temperature zone. Furthermore, a heat insulation layer or heat insulation material may be provided between each temperature zone to reduce heat transfer between temperature zones, thereby improving the temperature control accuracy. Of course, any number of temperature zones may be provided on the printing platform 2, and those skilled in the art may select a suitable number of temperature zones according to the actual design under the guidance of this application. It should be noted here that the temperature control component on the printing platform 2 may work in conjunction with the atmosphere temperature control system in the molding chamber 1 described in the aforementioned embodiment, so as to ensure that the 3D printing material for constructing the 3D object has a temperature that is conducive to molding when in contact with the printing platform 2, and to avoid warping or deformation of the 3D object due to temperature difference.

[0053] Generally, the molten material needs to be heated and melted after being granulated before being transported to the print head and extruded by the nozzle located on the print head. During the printing process, the continuous and uniform supply of the molten material needs to be ensured to ensure the smooth progress of the printing operation and the quality of the 3D object. However, the traditional fused deposition modeling 3D printing process can only print smaller 3D objects. If the printing length, width and height are several meters or more, such as large-scale anime shapes, company reception desks, outdoor art sculptures, etc., it is not suitable. In particular, its traditional 3D printing wire with a wire diameter of millimeters and its wire melting system cannot meet the above printing requirements.

[0054] To this end, the industry has proposed using industrial robots as the executive components of melt extrusion 3D printing to achieve large-scale 3D object printing. However, when using 3D printing robots for 3D printing, the overall size of the 3D printing robot is often large, especially the extension distance of its robotic arm is long, which leads to a long channel path for extrusion of the material after it is melted, which is not conducive to temperature control and makes it difficult to achieve a continuous and uniform supply of molten material. In addition, since the moving parts of the industrial robot include multiple articulated arms / robotic arms connected by multiple axes, during the movement process, the multiple robotic arms have different movement trajectories due to different movement angles and torques, which will affect the extrusion conveying path of the material after it is melted to a certain extent. For example, if the path is set too short, it will limit the freedom of the robot's articulated arm / robotic arm and affect the printing path. If the path is set too long, it will be not conducive to the temperature consistency of the molten fluid material, resulting in poor extrusion and affecting the printing efficiency.

[0055] Furthermore, ordinary screw extruders require a length-to-diameter ratio of more than ten times to complete the plasticization of the material, while the 3D printing robot's melt extrusion device moves with the robot's mechanical arm during the printing process, so it is impossible to design a longer length. For example, it is usually only 3-5 times the length-to-diameter ratio. With such a length, it only takes a few seconds from granular material to extruded fluid material. The granular material has no time to plasticize, and poorly plasticized materials are microscopically uneven. After printing is completed, the printed 3D object product will continue to release stress during subsequent use, thereby causing deformation of the 3D object. This is a major problem in using industrial robots as melt extrusion 3D printing, which urgently needs to be overcome by technical personnel in this field.

[0056] Therefore, this application is in the following Figures 5 to 18 In each of the illustrated embodiments, a 3D printing robot including a melt extrusion device is proposed, so as to achieve a continuous and smooth supply of molten fluid material while taking into account the robot's freedom.

[0057] The first robot 3 is used to construct the 3D object. In the aforementioned and subsequent embodiments, it is also referred to as a 3D printing robot, and will not be described in detail later when the 3D printing robot is mentioned.

[0058] See also Figure 5 Combined with Figure 1 ,in, Figure 5 The diagram is a schematic diagram of the structure of the first robot in one embodiment of the present application. Figure 1 and Figure 5 As shown, the first robot 3 is arranged on the first side of the printing platform 2, and includes a first robot arm 31 and a melt extrusion device 32. The first robot arm 31 can move on the upper side of the printing platform 2 according to the first movement path, and the melt extrusion device 32 includes a print head 321, which is arranged on the first robot arm 31 and is used to melt the powder or granular material and deposit it on the printing platform 2 according to the first printing path to form the 3D object layer by layer. Other specific configurations of the melt extrusion device 32 can refer to the description in the subsequent embodiments, which will not be repeated here.

[0059] Wherein, the first side of the printing platform 2 is as follows Figure 1The position of the first robot 3 shown, that is, as described in the above embodiment, the first robot 3 is arranged between the first right angle and the first obtuse angle in the molding chamber 1. In one implementation, the first robot 3 can be fixedly arranged on the first side of the printing platform 2. In order to achieve the fixation of the first robot 3, it can further include a first base 33. The first base 33 is used as a basic component of the first robot 3 to carry the first mechanical arm 31. In one example, the weight of the first base 33 is large to provide a firm stability of the whole machine, thereby reducing mechanical vibration and ensuring that the first robot maintains balance. The material of the first base 33 includes but is not limited to cast iron, alloy, and carbon structural steel, so that the first base 33 has sufficient rigidity and strength, thereby giving the first base 33 sufficient durability and carrying capacity. It should be understood that the first base 33 can be used as the base of the first mechanical arm 31 in the first robot 3, and its specific structure can be changed based on different functional requirements or structural requirements.

[0060] The end of the first robot arm 31 is provided with a print head 321 to provide the print head 321 with freedom of movement in space, thereby improving the flexibility of the printing operation. In this example, the first robot arm 31 and the print head 321 can be connected by at least one axial joint, and the axial joint enables the print head 321 to generate a rotational rotation centered along the axis of the first robot arm 31 or a hinged rotation perpendicular to the axis of the first robot arm 31. In order to further improve the freedom of movement of the print head 321 in space, the first robot arms 31 can be connected by at least one axial joint. For example, the first robot 3 can be configured as a six-axis industrial robot, which is provided with six axial joints to provide six-axis rotation. The six axial joints can be configured on the print head 321 and the first robot arm 31 separately or in combination.

[0061] In one embodiment, if Figure 5 As shown, the first robot arm 31 has a proximal end and a distal end relative to each other, the proximal end of which is connected to the first base 33, and the distal end of which is provided with a print head 321. It should be noted that in the subsequent embodiments, in order to clearly illustrate the relative positions of various components, structures, assemblies, mechanisms, components, or devices in the first robot, the proximal end and the distal end of the first robot arm are used as references for distinction, and the side of each component, structure, assembly, mechanism, component, or device that is relatively close to the proximal end of the first robot arm is called the proximal end (also called the proximal side), and the side that is relatively close to the distal end of the first robot arm is called the distal end (also called the distal side).

[0062] It should be understood that the first robotic arm 31 in the present application refers to a robot robotic arm including multiple robotic articulated arms. For example, in an embodiment where the first robot is a six-axis industrial robot, the first robotic arm 31 includes a first robotic articulated arm 310 and a second robotic articulated arm 311 .

[0063] Figure 5 The six axis joints are the first axis joint 312, the second axis joint 313, the third axis joint 314, the fourth axis joint 315, the fifth axis joint 316, and the sixth axis joint 317. The first axis joint 312 is connected to the first base 33, and provides a rotational rotation centered around the axis of the first base 33. The second axis joint 313 is connected to the proximal end of the first mechanical joint arm 310 and close to the first axis joint 312. The second axis joint 313 provides a hinge-type rotation around an axis perpendicular to the first mechanical joint arm 310 (which may correspond to the axis of the second axis joint 313). The third axis joint 314 is connected to the proximal end of the second mechanical joint arm 311, and provides a hinge-type rotation around an axis perpendicular to the second mechanical joint arm 311 (which may correspond to the axis of the third axis joint 314). The fourth axis joint 315 is connected to the distal end of the second mechanical joint arm 311, and provides a rotational rotation centered on the axis of the second mechanical joint arm 311. The fifth axis joint 316 and the sixth axis joint 317 can be arranged in cooperation with the print head 321 to provide hinged rotation and rotational rotation of the print head 321 respectively.

[0064] In some other examples, the first robot may also be configured as a five-axis industrial robot, which is provided with five axis joints to provide five-axis rotation. It should be noted that the axis joints may be configured to any number to meet actual production needs, and the present application does not impose any restrictions on this. For the sake of ease of description and explanation, the following embodiments are described by taking the first robot 3 configured as a six-axis industrial robot as an example, which should not be understood as a limitation on the present application.

[0065] In one embodiment, the first robotic arm 31 may be configured as a slender or thick approximately cylindrical shape, and may be made of a suitable rigid material, for example, a lightweight and high-strength metal alloy such as an aluminum alloy, a magnesium alloy, or a carbon composite material.

[0066] In one embodiment, each axis joint includes an angle encoder, which can provide relative rotation information of the first robot arm 31. The information provided by the encoders of all axis joints can determine the position where the print head accumulates 3D printing materials. Furthermore, a control device can control the 3D printing operation based on the rotation information provided by each encoder.

[0067] In the embodiment where the first robot is configured as a six-axis industrial robot, the control device is used to control the six axis joints to rotate, thereby controlling the first mechanical arm 31 to move along the first motion path, and then controlling the print head 321 to move along the first printing path, so as to achieve layer-by-layer deposition of 3D printing materials. The first motion path refers to the movement path of the first mechanical arm 31 during the entire printing process, and the movement path reflected in each mechanical joint arm in space is not the same. The first printing path refers to the movement path of the print head 321 when the 3D printing material is deposited during the movement of the first mechanical arm 31 along the first motion path. Further, the first printing path can be the movement path of the print head. In order to distinguish it from the second control device included in the second robot in the subsequent embodiments, the control device included in the first robot is referred to as the first control device, and the first control device and the second control device are not repeated later.

[0068] In one embodiment, the first control device includes a processing unit, a storage unit and a plurality of interface units. Each of the interface units is respectively connected to the first robot arm, the print head and other devices or components or mechanisms that are independently packaged and transmit data through the interface. The first control device also includes at least one of the following: a prompt device, a human-computer interaction device, etc. The interface unit determines its interface type according to the connected device, component or mechanism, which includes but is not limited to: a universal serial interface, a video interface, an industrial control interface, a wireless communication port, etc. The storage unit is used to store the printing program, and the processing unit is connected to the storage unit, and is used to control the various components or components or structures in the first robot 3 to coordinate and realize the 3D printing operation of the print head 321 when executing the printing program.

[0069] In one embodiment, the 3D object constructed by the first robot needs to be further processed, such as cutting it to obtain a smooth surface, or grinding, lapping, carving, drilling and other processing operations to meet user needs. In another embodiment, it is necessary to remove the support connected to the 3D object. In view of this, the second robot 4 included in the 3D printing device of the present application is used to further finely process and high-quality surface treatment the 3D object. In some embodiments, it can also be called a subtractive robot.

[0070] Please continue reading Figure 1 ,like Figure 1 As shown, the second robot 4 is arranged on the second side of the printing platform 2 and at a first preset angle with the first robot 3, and includes a second robot arm 41 and a cutting assembly 42. The second robot arm 41 can move on the upper side of the printing platform 2 according to a second motion path. The cutting assembly 42 is arranged on the second robot arm 41, and is used to perform subtractive processing on the 3D object deposited on the printing platform 2 according to the subtractive path.

[0071] The cutting component 42 is used to perform subtractive processing on a 3D object. For example, it can be configured as a milling cutter or a grinding wheel.

[0072] The second robot arm 41 and the first robot arm 31 may have the same configuration, which will not be described in detail here. In one example, the second robot 4 is configured as a six-axis industrial robot. The following embodiments are described by taking the second robot 4 as a six-axis industrial robot as an example, which should not be construed as a limitation of the present application. It should be understood that the second robot arm 41 in the present application refers to a robot arm including multiple mechanical joint arms.

[0073] In one embodiment, the second robot 4 further includes a second control device, which is used to control the six axis joints in the second robot 4 to rotate, thereby controlling the second robot 4 to move along the second motion path, and then controlling the cutting assembly to move along the subtractive path to achieve subtractive processing of the 3D object. The second motion path refers to the movement path of the second robot arm 41 during the entire printing process, and the subtractive path refers to the movement path of the cutting assembly when the 3D object is subtracted during the movement of the second robot arm 41 along the second motion path. The second control device has the same configuration as the first control device, and will not be repeated here.

[0074] In one embodiment, the stiffness of the second mechanical arm 41 of the second robot 4 is greater than the stiffness of the first mechanical arm 31 of the first robot 3. The stiffness refers to the ability of the first mechanical arm 31 or the second mechanical arm 41 to resist elastic deformation when subjected to force, and is used to characterize the ease with which the first mechanical arm 31 is deformed. It should be understood that the stiffness of the second mechanical arm 41 is greater than the stiffness of the first mechanical arm 31, which means that the force applied to the second mechanical arm 41 when the first mechanical arm 31 is deformed cannot cause the second mechanical arm 41 to deform. It should be noted that in the process of subtractive processing of 3D objects, a large cutting force will be generated, which will cause a large impact and vibration to the second mechanical arm 41. At this time, if the stiffness of the second mechanical arm 41 is insufficient, the second mechanical arm 41 will be deformed or the motion path of the second mechanical arm 41 will have an error, thereby affecting the processing accuracy and surface quality of the 3D object. Relatively speaking, in the process of depositing the molten 3D printing material layer by layer, the first mechanical arm 31 is subjected to a smaller force of molten extrusion, and the stiffness requirement for the first mechanical arm 31 is relatively low. Therefore, in this embodiment, the rigidity of the second robotic arm 41 needs to be greater than the rigidity of the first robotic arm 31 .

[0075] In one embodiment, the second side of the printing platform 2 is as follows Figure 1The position of the second robot 4 shown in the figure, that is, as described in the above embodiment, the second robot 4 is arranged between the second obtuse angle and the third obtuse angle in the molding chamber 1. In order to realize the arrangement of the second robot 4 on the second side of the printing platform 2, the second robot 4 may further include a second base 43, and the second base 43 may be configured in the same manner as the first base 33, which will not be described in detail here. In this embodiment, the first robot 3 and the second robot 4 have a first preset angle, and the first preset angle is the angle α between the connecting lines formed by the first robot 3, the center of rotation of the printing platform 2, and the second robot 4. Figure 1 In the example shown, the first preset angle α is 90°.

[0076] In another embodiment, the second side of the printing platform 2 is as follows Figure 2 The position of the second robot 4 shown in FIG. 1 is that, as described in the above embodiment, the second robot 4 is arranged between the second right angle and the fourth obtuse angle in the molding chamber 1. Figure 2 In the example shown, the first preset angle α is 180°.

[0077] In one embodiment, the working area of ​​the second mechanical arm 41 of the second robot 4 performing the subtractive processing on the upper side of the printing platform 2 according to the second motion path occupies 75%-100% of the area of ​​the molding surface on the printing platform 2, wherein the molding surface refers to the area on the printing platform 2 for depositing 3D printing materials for building 3D objects, and its range may be less than or equal to the range of the printing platform 2. For example, the working area of ​​the second motion path on the upper side of the printing platform 2 may occupy approximately 75%, 80%, 85%, 90%, 95%, or 100% of the molding surface area.

[0078] In one embodiment, in an example where the working area of ​​the second motion path occupies 75% of the area of ​​the forming surface, see Figure 6 , which is a schematic diagram showing the working area occupied by the second motion path on the molding surface of the printing platform in one embodiment of the present application, Figure 6 The second robot 4 is indicated by a small circle, the printing platform 2 is indicated by a large circle, and the shaded part indicates the range of the working area on the molding surface 21 occupied by the second robot 4. In this example, the length of the second robot arm 41 is set within a suitable range to ensure that the working area of ​​the second motion path can occupy at least 75% of the area of ​​the molding surface 21, so that the second robot 4 can achieve the cutting operation of the entire 3D object without changing its position through the cooperation of the rotation of its six axes and the rotation of the printing platform 2.

[0079] It should be noted here that Figure 6The working area occupied by the second robot 4 on the molding surface 21 when it is arranged between the second obtuse angle and the third obtuse angle in the molding chamber 1 is only schematically represented, which should not be understood as a limitation of the present application. For example, in another example, the second robot 4 is arranged between the second right angle and the fourth obtuse angle. At this time, the working area of ​​the second motion path on the upper side of the printing platform 2 can still occupy 75%-100% of the molding surface area.

[0080] In one embodiment, see Figure 7 , which is a schematic diagram showing that the first motion path and the second motion path occupy the printing area and the working area of ​​the printing platform respectively in one embodiment of the present application, Figure 7 In the figure, two small circles respectively indicate the first robot 3 and the second robot 4, a large circle indicates the printing platform 2, and the shadow areas corresponding to the first robot 3 and the second robot 4 respectively indicate the first motion path and the second motion path. As shown in the figure, the first robot 3's first mechanical arm 31 prints in the upper side of the printing platform 2 according to the first motion path, and the second robot 41 performs subtractive processing in the upper side of the printing platform 2 according to the second motion path, which intersect at the center of rotation of the printing platform 2. In this way, the first robot 3 and the second robot 4 can print and cut the 3D object at the same time. While maximizing the printing area and the working area, the printing operation and the cutting operation do not interfere with each other, thereby improving the manufacturing efficiency of the 3D object, and can also achieve 100% coverage of the entire platform molding area by time-sharing operation with the help of the rotation of the printing platform.

[0081] In another embodiment, the printing area of ​​the first robot's first mechanical arm on the upper side of the printing platform according to the first motion path and the subtractive processing operation area of ​​the second robot's second mechanical arm on the upper side of the printing platform according to the second motion path respectively occupy 75%-100% of the area of ​​the molding surface on the printing platform, expanding the single area area of ​​the printing area and the operation area. For details, please refer to Figure 6 The description of any embodiment in the above will not be repeated here. For example, the printing area and the operation area may occupy approximately 75%, 80%, 85%, 90%, 95%, or 100% of the molding surface area, respectively. Of course, the second robot arm of the second robot may also be configured to print 3D objects, which may be determined according to actual production requirements.

[0082] As mentioned above, it is difficult for the valve mechanism in the related art to achieve complete closure of the print head, which will cause leakage of molten material, thereby affecting printing accuracy; and if the valve mechanism is completely closed, the fluid material inside the valve mechanism will generate pressure due to thermal expansion, which will press the closed valve mechanism to the inner wall of the valve cavity, and produce direct mechanical contact with the print head, which will not only make it impossible to reopen the next time it is used, or require greater force to force the switch, which will cause mechanical wear of the valve mechanism, and after repeated use, the valve mechanism is prone to loosening and thus affect its service life. Long-term use will also cause damage to the print head, thereby affecting the smooth progress of 3D printing operations. In view of this, the present application discloses a melt extrusion device for a 3D printing robot in some embodiments, which can achieve complete closure of the print head and avoid direct mechanical contact with the print head, thereby ensuring printing accuracy and the smooth progress of printing operations.

[0083] like Figure 5 As shown, the melt extrusion device 32 may further include a storage container 320 and a feeding system 322 based on the print head 321 described in the above embodiment.

[0084] exist Figure 5 In the illustrated embodiment, the accumulator 320 is used to cache 3D printing materials such as powder or granular materials. In this embodiment, the accumulator 320 is connected to the external silo through an air pipeline, and a portion of the air pipeline is arranged in the first mechanical arm between the second axis joint 313 and the third axis joint 314. That is, the air pipeline is arranged in the first mechanical joint arm 310. In this embodiment, the external silo is used for long-term and large-scale storage of granular materials to ensure sufficient supply of raw materials, and the granular materials are transported to the accumulator 320 through the air pipeline. The accumulator 320 is used for temporary storage of granular materials, and the flow rate of the granular materials can be adjusted to ensure that the subsequent transportation of the granular materials can be carried out smoothly. In one example, a negative pressure airflow can be generated in the air pipeline by an air source device such as a blower or a compressor to promote the transportation of granular materials in the air pipeline.

[0085] In one embodiment, the pellets buffered in the accumulator 320 are transported to the feeding system 322 by a feeding screw disposed at the bottom of the accumulator 320. In one example, the feeding screw can uniformly and continuously transport the pellets from the accumulator 320 to the feeding system 322 by rotational motion. The feeding screw can be configured to include a screw body, a spiral blade, a spiral thread, and a spiral drive device. The material of the screw body can be configured to be metal, and its surface is smooth, so that the pellets can be smoothly transported. The spiral blades and the spiral threads are arranged in a spiral shape along the axis of the screw body to push the pellets to move during the rotation process. The pitch between the spiral blades and the spiral threads can be determined according to the properties of the pellets, and this application is not limited. The spiral drive device can be configured as a drive motor, which is used to provide power for the rotation of the screw body.

[0086] In one embodiment, the feeding system 322 is disposed on the mechanical arm of the 3D printing robot, and is used to melt the 3D printing material such as powder or granular material into a fluid material and output it through the feeding channel 323 under pressure. It should be noted that the 3D printing robot may be, for example, the first robot 3 described in the aforementioned embodiment. In this example, the mechanical arm included in the 3D printing robot may be the first mechanical arm 31 included in the first robot 3 described in the aforementioned embodiment. The 3D printing robot and the mechanical arm included in the 3D printing robot will not be described in detail in the subsequent embodiments.

[0087] In one embodiment, if Figure 5 As shown, the feeding system 322 can be arranged on the mechanical arm of the third axis joint 314 and the fourth axis joint 315, that is, arranged on the second mechanical joint arm 311. Specifically, in order to maximize the reduction of the burden on the second mechanical joint arm 311 and avoid interfering with the flexibility of the second mechanical joint arm 311 when moving, the feeding system 322 can be configured at a position close to the third axis joint 314. Of course, in certain other embodiments, the feeding system 322 can also be arranged on the first mechanical joint arm 310 and the second mechanical joint arm 311 at the same time, and is carried by the first mechanical joint arm 310 and the second mechanical joint arm 311 at the same time. The material of the feeding system 322 includes but is not limited to metal, and the connection method with the mechanical arm includes but is not limited to welding and one-piece molding connection. The specific configuration method and configuration position are determined according to actual production needs, and this application does not limit this.

[0088] See also Figure 8 Combined with Figure 5 ,in, Figure 8 The schematic diagram of the structure of the feeding system in one embodiment of the present application is shown as follows: Figure 5 and Figure 8 As shown, the feeding system 322 includes one or more heaters for heating and melting the 3D printing material.

[0089] In one embodiment, the melting temperature range of heating the 3D printing material is 130°C-240°C, for example, approximately 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, or 240°C, etc.

[0090] In the embodiment where the heater is configured as multiple, the feeding system 322 may further include a melt barrel 3221 and a screw mechanism (not shown), the melt barrel 3221 is connected to the storage container 320, the multiple heaters are sleeved on the circumference of the melt barrel 3221, and the screw mechanism is arranged inside the melt barrel 3221 and along the axial direction of the melt barrel 3221, and is used to drive the molten fluid material to be pressurized and extruded toward the outlet direction of the melt barrel 3221 when rotating. Figure 5 and Figure 8 In the illustrated embodiment, the melt barrel 3221 is used to receive the granular material delivered by the feeding screw arranged at the bottom of the storage container 320, and the multiple heaters are used to heat and melt the granular material into a fluid material. The screw mechanism can rotate to stir and mix the unmelted granular material and the molten fluid material to achieve sufficient melting of the granular material, and the molten fluid material is pressurized and extruded toward the outlet direction of the melt barrel 3221.

[0091] In order to provide power for the rotational movement of the screw mechanism, in one embodiment, the feeding system 322 includes a drive motor 3225 disposed at the proximal end of the melt barrel 3221 and linked to the screw mechanism. In one example, the drive motor 3225 may also include a speed regulator, which may control the rotation speed of the drive motor, thereby controlling the rotation speed of the screw mechanism, and thus controlling the speed at which the fluid material is extruded. In an embodiment, the drive motor 3225 is, for example, a servo motor, and the speed regulator is, for example, a reducer linked to the servo motor; of course, in other embodiments, the speed regulator is also, for example, a control circuit of the servo motor to control the rotation speed of the servo motor.

[0092] In certain other embodiments, the screw mechanism may further include a screw body, a spiral thread, and a spiral blade on the basis of including a driving motor 3225. The specific structure and function of the screw body, spiral thread and spiral blade can be found in the description of the previous embodiments and will not be repeated here.

[0093] Considering that the melt barrel, the main component of the 3D printing robot feeding system, moves with the robot's mechanical arm during the printing process and cannot be designed to be longer, that is, the melt barrel as the main body of the feeding system cannot be simultaneously straddled on two mechanical joint arms (otherwise it will affect the freedom of movement of the mechanical arms). Therefore, the melt barrel can only be set on one of the mechanical joint arms, that is, the aforementioned second mechanical joint arm. In order to avoid shortening the heating path from the granular material to the extruded fluid material and affecting the uniformity of the plasticization of the granular material, the present application designs a spiral microchannel and multi-stage heating on the melt barrel, and then heats the feeding channel with more freedom of movement to extend the heating path of the fluid material, so that the granular material can be fully plasticized and present as shown below. Figure 5 and Figure 8 Embodiment described.

[0094] In this embodiment, if Figure 5 and Figure 8 As shown, the heater includes a preheater 3222 and a main heater, wherein the preheater 3222 is sleeved in the middle area of ​​the melting barrel 3221, and the main heater is sleeved at the distal end of the melting barrel 3221. It should be understood that the preheater 3222 is used to preliminarily heat the granular material entering the melting barrel 3221 within a temperature range, so that the temperature of the granular material is increased to a near-molten state, and the main heater is used to further increase the temperature of the material within a certain temperature range to fully melt the material. The preheater 3222 cooperates with the main heater to gradually increase the temperature of the material, thereby reducing thermal shock and temperature fluctuations to ensure that the material is heated evenly.

[0095] In one example, the heating temperature range of the preheater 3222 is 80℃-120℃, for example, it can be approximately 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃, 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, 116℃, 117℃, 118℃, 119℃, or 120℃, etc.

[0096] In one embodiment, if Figure 8As shown, the main heater includes a first main heater 3223 and a second main heater 3224, wherein the first main heater 3223 is sleeved at the distal end of the melt barrel 3221, and the second main heater 3224 is located between the preheater 3222 and the first main heater 3223. Specifically, the second main heater 3224 is used to further heat the material heated by the preheater 3222 so that it is completely melted into a fluid material. In one example, the heating temperature range of the second main heater 3224 is 120°C-220°C, for example, it can be approximately 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, or 220°C.

[0097] The first main heater 3223 is used to maintain the material heated by the second main heater 3224 in a molten fluid state, so that the temperature of the fluid material is constant. In one example, the heating temperature range of the first main heater 3223 is 220°C-240°C, for example, it can be approximately 220°C, 221°C, 222°C, 223°C, 224°C, 225°C, 226°C, 227°C, 228°C, 290°C, 230°C, 231°C, 232°C, 2330°C, 234°C, 235°C, 236°C, 237°C, 238°C, 239°C, or 240°C. It should be noted that the preheater 3222, the second main heater 3224, and the first main heater 3223 can be adjusted according to the properties of the granular material that actually needs to be melted under the technical enlightenment of this application.

[0098] In order to maintain the heating temperature of the preheater 3222 and the main heater within their respective heating temperature ranges, in one embodiment, the feeding system 322 includes one or more temperature sensors for detecting the temperature of the molten material, and the temperature sensors are used to monitor the material temperature in the respective heating areas of the preheater 3222 and the main heater in real time. Matchingly, the feeding system 322 can also be further configured with a temperature controller and a cooling device, and the cooling device is used to provide cooling for the melt barrel section between the preheater 3222 and the accumulator 320 to prevent the granular material at the feed port from softening and getting stuck in the throat when it encounters heat. It can be, for example, a cooling water circulation device and a refrigerant circulation device. Specifically, when the temperature sensor detects that the material temperature in each heating area is lower than the corresponding heating temperature range, the temperature controller controls the preheater 3222 and the main heater to operate until the material temperature in each heating area is within the corresponding heating temperature range, and maintains the set temperature in a thermal compensation manner. When the temperature sensor detects that the material temperature is higher than the corresponding heating temperature range, the temperature controller controls the heater to stop working or the auxiliary cooling device to operate until the material temperature in each heating area is within the corresponding heating temperature range again.

[0099] In some embodiments, the one or more temperature sensors are connected to a computer system of a 3D printing robot that controls one or more heaters based on the temperature reported by the one or more temperature sensors. For example, the computer system can control one or more heaters to adjust the temperature of the material in each of the heaters, feed channels and / or nozzles. In some embodiments, the system operates as a closed-loop feedback system to maintain an approximately constant temperature of the device or device component (i.e., a barrel, nozzle or feed channel). The temperature of the material in different components of the device can be the same or different. In some embodiments, the feedback system is controlled using a proportional integral derivative (PID) controller, a Bang-Bang controller, a predictive controller, a fuzzy control system, or any other suitable algorithm.

[0100] In one embodiment, the feeding system 322 includes a pressure sensor for detecting the pressure of the fluid material in the extrusion channel of the print head. The structure and function of the extrusion channel can refer to the description in the subsequent embodiments. The types of the pressure sensor include but are not limited to piezoelectric sensors, strain gauge sensors, and capacitive sensors. According to the real-time monitoring of the pressure fluctuations in the entire feeding process by the pressure sensor, the speed of the extruded molten fluid material can be controlled, and then the speed of the material deposited on the printing platform can be controlled. In this embodiment, the pressure sensor is also configured with a computer feedback system, and the computer feedback system can use a proportional integral differential (PID) controller, a Bang-Bang controller, a predictive controller, a fuzzy control system, an expert system controller or any other suitable control algorithm. In some embodiments, the sampling rate of the pressure sensor is about 20ms or faster, such as about 10ms or faster, about 5ms or faster, or about 2ms or faster. In some embodiments, the pressure of the fluid material in the extrusion channel is controlled within a preset target pressure.

[0101] As mentioned above, the granular material is transported from the external material bin to the accumulator 320 through the gas pipeline, and then transported to the feeding system 322 through the feeding screw configured at the bottom of the accumulator 320. The feeding system 322 heats and melts the granular material into a fluid material through the preheater 3222 and the main heater, and the screw mechanism located inside the feeding system 322 pressurizes and extrude the fluid material. Subsequently, the fluid material is output to the print head 321 through the feeding channel 323.

[0102] like Figure 5 As shown, the feed channel 323 is disposed between the end of the melt barrel 3221 and the print head 321, and except for the two ends of the feed channel 323 being physically connected to the melt barrel 3221 and the print head 321, the pipeline between the two ends of the feed channel 323 is not physically connected to other parts of the first robot 3, so that the feed channel 323 does not limit the freedom of the robot joint arm / mechanical arm. In this embodiment, the axis of the starting end of the feed channel 323 is almost perpendicular to the axis of the melt barrel 3221 and extends horizontally, as shown in FIG. Figure 8 In the state shown, the feeding channel 323 extends in a direction away from the second mechanical joint arm so as not to affect the movement trajectory or movement route of the second mechanical joint arm 311 , the fourth axis joint 315 and the print head 321 .

[0103] In this embodiment, the length of the feed channel 323 is greater than the maximum movement distance between the fourth axis joint 315 of the first robot 3 and the print head 321. It should be understood that in the example where the 3D printing robot is configured as a six-axis industrial robot, the print head 321 located at the end of the first robot arm has multiple degrees of freedom in space by means of the movement of multiple joints and articulated arms. In this embodiment, the length of the feed channel 323 is greater than the maximum distance between the fourth axis joint 315 and the print head 321, which can avoid limiting the movement of the print head 321 in space, ensuring that the print head 321 does not generate additional resistance during the printing process, thereby ensuring the accuracy of printing.

[0104] In one embodiment, the feed channel 323 includes a pipeline body and a temperature control device. The pipeline body has a third stiffness, and correspondingly, the first mechanical arm 31 has a first stiffness. Among them, the stiffness refers to the ability of the first mechanical arm 31 or the pipeline body to resist elastic deformation when subjected to force, which is used to characterize the ease with which the first mechanical arm 31 or the pipeline body is deformed. The stiffness is determined by the material and structure of the rigid body. The greater the stiffness, the stronger the ability of the rigid body to resist deformation. Conversely, the smaller the stiffness, the weaker the ability of the rigid body to resist deformation. In one example, the third stiffness is less than the first stiffness. It should be understood that the third stiffness of the pipeline body is less than the first stiffness of the first mechanical arm 31, which means that when the pipeline body is deformed, the force applied to the first mechanical arm 31 cannot cause the first mechanical arm 31 to deform. This means that the pipeline body can be configured as a hose structure. It should be noted that when connecting the feeding system 322 and the print head 321, the direction of the pipeline body needs to be adjusted, and the smaller stiffness makes the pipeline body easy to install; in addition, the smaller stiffness can reduce the instantaneous pressure changes caused by the internal molten fluid material, thereby ensuring the smooth flow of the fluid material, and then ensuring that the fluid material can be evenly extruded by the print head; furthermore, since the third stiffness is smaller than the first stiffness, the pipeline body with smaller stiffness makes it possible for the feeding channel 323 to not generate reaction force or traction force to resist the above movement and limit the freedom of the robot joint arm / mechanical arm when the joint arm between the four-axis joint 315 of the first robot arm 31 and the print head 321 performs rotation, extension and contraction movements.

[0105] In one embodiment, the body of the feed channel 323 is a high temperature resistant rubber tube, plastic tube or metal corrugated tube.

[0106] In another embodiment, the feed channel 323 has a high temperature resistant hose with a threaded support structure. When the threaded support structure is a continuous support body of a preset length, the hose body is a threaded tube, or a certain section of the high temperature resistant hose body is a threaded tube; when the threaded support structure is an interval support body of a preset length, at least two sections of the hose body are threaded tubes. Here, the threaded tube is made of rubber or metal, and the threaded tube can be easily bent under the action of external force but will not collapse under the negative pressure generated in the hose body, or collapse at the bend during large bending, thereby ensuring the fluidity of the fluid material during the process of conveying the molten fluid material.

[0107] In some embodiments, in order to better ensure the support of the threaded tube, the threaded tube can be further a steel wire threaded tube, and the steel wire threaded tube is a three-layer structure. The inner and outer layers of the three-layer structure are made of plastic materials, such as PTFE (Polytetrafluoroethylene), etc.; the middle layer is a steel wire reinforcement structure, such as a spiral steel wire, etc. Therefore, the steel wire reinforcement structure can ensure to a greater extent that the threaded tube will not collapse under the action of negative pressure, enhance the support force, and ensure the fluidity of the fluid.

[0108] In one embodiment, the temperature control device is disposed on the pipeline body. It should be understood that the distance between the feed channel and the print head is relatively far, and the fluid material may generate heat loss during long-distance transportation, causing the fluid material to gradually cool and stagnate, or the viscosity of the fluid material to increase due to heat loss, thereby causing the material to be blocked in the pipeline body. Therefore, in order to ensure that the fluid material can be stably transported to the print head, the temperature control device is disposed on the pipeline body of the present application.

[0109] In one implementation, the temperature control device is configured as a computer system or a thermostat, a temperature sensor embedded in the pipeline body, and a heating wire wrapped around the pipeline body. An auxiliary cooling element may be further configured to quickly reduce the excessive temperature of the fluid material. Of course, the temperature control device may also be configured in other forms as long as it can heat and maintain a constant temperature of the fluid material in the pipeline body.

[0110] In order to control the fluid material in the pipeline body at a suitable temperature, in one embodiment, the feed channel 323 is provided with a temperature control sensor. The temperature control sensor can cooperate with the temperature control device. Specifically, when the temperature control sensor detects that the material temperature in the pipeline body is lower than a threshold, the temperature controller controls the heating wire to operate until the material temperature reaches the threshold. When the temperature sensor detects that the material temperature is higher than the threshold, the temperature controller controls the heating wire to stop operating until the material temperature reaches the threshold again. The threshold is a temperature value or temperature range pre-set by the operator that can make the material in a molten state.

[0111] In one embodiment, see Fig. 9 , which is a schematic diagram of the structure of a print head in one embodiment of the present application, wherein the dotted line in the figure only schematically represents the internal structure of the print head 321, such as Fig. 9 As shown, the print head 321 includes a print head body 3211, a valve cavity 3212 located in the print head body 3211, a valve core 3213 disposed in the valve cavity 3212, an extrusion channel 3214 connected to the supply channel 323, and a nozzle 3215 connected to the extrusion channel 3214. The nozzle 3215 includes a tapered extrusion port 32151 for printing fluid material.

[0112] In this embodiment, the valve core 3213 can rotate at a certain angle in the valve cavity 3212 to switch the extrusion channel 3214 and the nozzle 3215 between the open state and the closed state. In other words, after the granular 3D printing material is heated to a molten fluid material by the heater of the feeding system 322, the fluid material is output to the print head 321 through the feeding channel 323, specifically, the feeding channel 323 connected to the print head body 3211 is output to the extrusion channel 3214, and then output to the valve core 3213. When the valve core 3213 is in the open state, the fluid material can be output to the nozzle 3215 through the extrusion channel 3214, and finally extruded through the tapered extrusion port 32151 and deposited on the printing platform. When the valve core 3213 rotates to the closed state, the fluid material is only output to the valve core 3213 and stops flowing to the subsequent structure.

[0113] In one embodiment, an access device 324 is disposed on the upper side of the print head 321. Fig.10 Combined with Fig. 9 ,in, Fig.10 The structure diagram of the print head configured with the access device in one embodiment of the present application is shown. Fig.10 As shown, the access device 324 is arranged along the first direction, and is used to connect the feeding channel 323 and the extrusion channel 3214. Fig. 9 and Fig.10In the illustrated embodiment, the pipeline of the access device 324 connected to the feed channel 323 is horizontally arranged so as to conform to the bending trend of the feed channel 323, that is, the feed channel 323 is laterally accessed from a direction away from the print head 321, so as to avoid causing the end of the feed channel 323 to have a large curvature to affect the smoothness of its internal channel. The pipeline of the access device 324 connected to the extrusion channel 3214 is vertically arranged, that is, the access device 324 is connected to the feed channel 323 and is perpendicular to the extrusion channel 3214 in space.

[0114] In order to clarify the definition of direction and the operation mode between different structures, a three-dimensional space defined by a first direction, a second direction, and a third direction is defined in the embodiments disclosed in the present application. The first direction, the second direction, and the third direction are all straight lines and are perpendicular to each other. For example, the length extension direction of the access device is defined as the first direction or the horizontal direction (for example Fig. 9 The direction in which the length of the valve core extends is defined as the second direction (for example, Fig. 9 The vertical direction is also called the vertical direction, the vertical line direction, or the up-down direction, and is defined as the third direction or vertical (for example Fig. 9 The first direction, the second direction, and the third direction will not be described in detail in the subsequent embodiments.

[0115] In one embodiment, both ends of the access device 324 are provided with compensation heaters for heating the fluid material passing through the access device 324, and the types of the compensation heaters include but are not limited to resistance heaters, heating windings, and heating cables. It should be understood that when the 3D printing material, such as powder or granular material, is heated to a molten fluid material by the heater of the feeding system, the fluid material needs to be output from the feeding system 322 to the print head 321 through the feeding channel 323. In this process, in order to avoid the heat loss of the fluid material, in order to ensure that the fluid material reaches the viscosity requirement for smooth extrusion, in particular, the channel of the access device 324 and the extrusion channel 3214 are perpendicular to each other in space, in order to avoid the fluid from being blocked in a large turn, before the fluid material is output to the extrusion channel 3214, it is necessary to perform compensation heating on the fluid material, and further control the viscosity of the fluid material to maintain a relatively low state, so as to ensure that it is in a fluid state that meets the extrusion requirements.

[0116] In one embodiment, if Fig.10As shown, the two sides of the print head 321 are symmetrically provided with terminal heaters 3216 for heating the fluid material in the print head 321. It should be understood that when the valve core 3213 rotates in the valve cavity 3212 to switch between the open state and the closed state, the fluid material should be ensured to be in the best flow state so that the friction force on the valve core 3213 when rotating in the valve cavity 3212 can be minimized. Therefore, it is necessary to set the terminal heater 3216 at the position corresponding to the valve core 3213 on the print head 321 to avoid the viscosity of the fluid material from increasing, so as to minimize the obstruction when the valve core 3213 rotates.

[0117] In one embodiment, in order to avoid the increase of viscosity of the fluid material due to insufficient temperature and carbonization due to excessive heating, thereby avoiding hindering the switching of the valve core 3213 in the valve chamber 3212, a terminal temperature sensor for detecting the temperature of the fluid material in the print head 321 is provided on the print head 321, and the terminal temperature sensor can monitor the temperature of the fluid material at the valve core 3213 in real time. Matchingly, a temperature controller and a cooling device can also be configured to achieve control of the temperature of the fluid material. The specific functions of the temperature controller and the cooling device can refer to the description in the above embodiments, and will not be repeated here.

[0118] In one embodiment, before the valve core 3213 switches from the closed state to the open state, such as before starting a new printing task or before the 3D printing robot is started, the material left in the valve cavity 3212 in the previous printing task solidifies into a solid state due to long-term cooling and is embedded in the valve cavity 3212. Therefore, the terminal heater 3216 preheats the material reserved in the print head 321 and melts it into a fluid material. It should be noted that when the 3D printing job is completed, the valve core 3213 will switch from the open state to the closed state, and the fluid material will be reserved between the valve core 3213 and the valve cavity 3212. As the temperature cools, the reserved fluid material will solidify again and lock the valve core 3213 in the valve cavity 3212. At this time, if the valve core 3213 needs to be switched to the open state, the solidified material reserved in the valve core 3213 and the valve cavity 3212 needs to be melted into a fluid material again to unlock the valve core 3213.

[0119] As mentioned above, the terminal heater 3216 heats and melts the material reserved in the print head 321 into a fluid material, and the valve core 3213 can be switched from a closed state to an open state. At the same time, the feeding system 322 outputs the fluid material to the print head through the feeding channel 323. Thereafter, the fluid material reserved in the print head 321 and the fluid material output by the feeding system 322 are output to the nozzle 3215 through the opened valve core 3213, and finally extruded through the aforementioned conical extrusion port 32151.

[0120] Furthermore, before starting a new printing task or before the 3D printing robot is turned on, it takes some time for the melted fluid material of the granular material newly entering the melt barrel 3221 to output the fluid material to the print head through the feed channel 323. If the 3D printing robot is already moving to execute the printing instruction at this time, the material left in the valve chamber 3212 in the previous printing task will be melted into fluid material and will be delivered to the nozzle in time to avoid empty coating of the nozzle of the print head. In other words, the groove formed on the shaft body of the print head of the present application also has the function of pre-storing part of the printing material to achieve seamless connection with the newly flowing in fluid material.

[0121] In one embodiment, in order to smoothly guide the fluid material to the tapered extrusion port 32151, reduce the resistance and turbulence of the fluid material when it flows, ensure that the flow of the fluid material inside the nozzle 3215 is more stable, and the sensor more accurately detects the real temperature inside the nozzle, the nozzle 3215 includes a tapered inner cavity surrounded by a tapered inner surface. It should be understood that with the cooperation of the tapered inner cavity and the tapered extrusion port 32151, the cross-sectional area of ​​the fluid material gradually decreases when passing through the nozzle 3215, so that the fluid material can be extruded and deposited on the printing platform at a higher flow rate and more evenly.

[0122] In one embodiment, see Figures 11 to 13 ,in, Fig.11 and Fig.12 They are schematic diagrams showing the structure of the valve core in different viewing angles in one embodiment of the present application. Fig.13 The cross-sectional view of the valve core in one embodiment of the present application is shown. Figures 11 to 13 As shown, the valve core 3213 includes a shaft body 32131, a flow channel 32132 radially penetrating the shaft body 32131, and a sink 32133 partially surrounding the shaft body 32131. The partially surrounding means that the area where the sink 32133 surrounds the shaft body 32131 is an open arc structure.

[0123] In one embodiment, the flow channel 32132 has an inlet hole 321321 and an outlet hole 321322. Fig.12 As shown, the inlet holes 321321 of the flow channel 32132 are all located in the sink 32133, so that the fluid material from the extrusion channel 3214 can be filled into the sink 32133, and the valve core 3213 is in Fig.12 In the open state shown, the flow channel 32132 connects the extrusion channel 3214 and the tapered extrusion port 32151 to allow the fluid material to flow through the nozzle 3215 .

[0124] In one embodiment, if Fig.11As shown, the outlet hole 321322 of the flow channel 32132 is partially located in the sink 32133. That is to say, in the embodiment where the sink 32133 is configured as an open arc-shaped structure, a part of the outlet hole 321322 is located in the arc-shaped structure, and another part is located outside the arc-shaped structure. Fig.14 , which is a schematic diagram showing a valve core in a closed state in one embodiment of the present application. Fig.14 As shown, when the valve core 3213 is in a closed state, the outlet hole 321322 of the flow channel 32132 is misaligned with the tapered extrusion port 32151 to prevent the fluid material from flowing through the nozzle 3215 and to keep the fluid material filled in the sink 32133 between the valve core 3213 and the valve cavity 3212 .

[0125] In one embodiment, please combine Figures 9 to 12 , the shaft body 32131 is arranged in the valve cavity 3212 along the second direction. In order to realize the rotational movement of the valve core 3213 in the valve cavity 3212, the valve core 3213 is axially connected to the valve cavity 3212, such as Fig.11 As shown, the shaft body 32131 includes a rotating shaft section 321311 and a suspended section 321312, the rotating shaft section 321311 is axially connected to both sides of the valve chamber 3212, and the suspended section 321312 is located between the rotating shaft sections 321311 on both sides. In this example, the flow channel 32132 and the sink 32133 corresponding to the extrusion channel 3214 are formed in the suspended section 321312.

[0126] In one embodiment, to further realize the rotation of the valve core in the valve cavity, the valve core 3213 can cooperate with an actuator. Fig.15 Combined with Fig. 9 ,in, Fig.15 The schematic diagram of the valve core and the actuator in one embodiment of the present application is shown as follows: Fig. 9 and Fig.15 As shown, the first end of the shaft body 32131 is connected to the actuator 3217, and the actuator 3217 is used to drive the valve core 3213 to rotate, thereby realizing the valve core 3212 Fig.12 The open state shown is the same as Fig.14 It should be understood that the first end corresponds to the right side of the shaft body 32131, and the second end described in the subsequent embodiments is the side away from the first end, that is, the left side of the shaft body 32131. The first end and the second end will not be repeated in the following. Fig. 9 and Fig.15In the example shown, the actuator 3217 is disposed in the print head 321 in a first direction perpendicular to the second direction, and is movably connected to the first end of the shaft body 32131. In other words, the shaft body 32131 and the actuator 3217 are perpendicular to each other in space, and the actuator 3217 is movably connected to the first end of the shaft body 32131.

[0127] In one embodiment, the actuator 3217 is configured as a pneumatic actuator. In this embodiment, the actuator 3217 can be configured as a cylinder, including a slider 32171 and pistons fixedly disposed at both ends of the slider 32171. For the convenience of distinction and description, the pistons 32172 and 32173 disposed at both ends of the slider 32171 are described as the first piston 32172 and the second piston 32173, respectively, and will not be repeated when the first piston 32172 and the second piston 32173 are mentioned later. The body of the slider 32171 is movably connected to the first end of the shaft body 32131, and the two ends of the first piston 32172 and the second piston 32173 are respectively configured to move linearly in the slider 32171 when driven by the air pressure generated by the cylinder 3217 to drive the shaft body 32131 to rotate.

[0128] In one implementation, the shaft body 32131 is movably connected to the body of the slider 32171 via a spline 3218 surrounding the first end. Specifically, a rack is provided at the position where the slider 32171 contacts the spline 3218, and the rack can mesh with the spline 3218, thereby driving the shaft body 32131 to rotate. For example, Fig.15 In the example shown, the valve core 3213 is in the open state. At this time, the first piston 32172 is driven by the gas in the first air pressure tube 3219, and moves linearly in the slider 32171 along the direction of the arrow indicated by the dotted line in the figure, which will drive the shaft body 32131 to rotate counterclockwise, so that the outlet hole of the flow channel is misaligned with the tapered extrusion port, thereby switching the valve core 3213 to the closed state. If the valve core 3213 needs to be switched to the open state again, it is only necessary to drive the second piston 32173 with the gas in the second air pressure tube 3220, so that the second piston 32173 moves linearly in the slider 32171 in the direction opposite to the arrow, thereby driving the shaft body 32131 to rotate clockwise until the outlet hole of the flow channel is connected to the tapered extrusion port.

[0129] In this embodiment, the choice of the two-choice air circuit consisting of the first air pressure tube 3219 and the second air pressure tube 3220 can be configured such that the computer control system drives the end solenoid valve according to the instructions of the printing program, and the action time can be 0.1s-0.5s, for example, approximately 0.1s, 0.2s, 0.3s, 0.4s or 0.5s, etc., depending on the actual situation.

[0130] In one embodiment, the actuator 3217 is configured as a mechanical actuator. In this embodiment, the first piston 32172 and the second piston 32173 can be configured to be driven by a mechanical force such as a motor, such as a driving source such as a servo motor. The specific driving process can be referred to the above description and will not be repeated here.

[0131] In one embodiment, in order to switch the valve core 3212 between the open state and the closed state, the rotation angle of the shaft body 32131 is 15-45°, preferably, the rotation angle is 20°. For example, the rotation angle can be configured as 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, or 45°, etc. It should be understood that the rotation angle can be adjusted accordingly according to the setting position of the inlet and outlet of the flow channel.

[0132] See also Fig.16 and Fig.17 , Fig.16 It is a cross-sectional schematic diagram showing a valve core in an open state in a valve cavity in one embodiment of the present application; Fig.17 The figure shows a cross-sectional schematic diagram of a valve core in a closed state in a valve cavity in one embodiment of the present application; Fig.16 The valve core 3213 shown is in an open state in the valve cavity 3212. In this state, the extrusion channel 3214 and the inlet hole 321321, flow channel 32132, outlet hole 321322 of the valve core 3213 and the flow channel of the nozzle are in a connected state. When the feeding system 322 outputs the fluid material to the print head 321 through the extrusion channel 3214 of the access device 324 via the feeding channel 323, the fluid material is output to the valve core 3213 through the extrusion channel 3214 perpendicular to the feeding channel 323, and while being filled in the sink 32133, it is output to the nozzle through its flow channel 32132 through the outlet hole 321322 to achieve subsequent printing operations. When it needs to be closed, as shown in FIG. Fig.17 The valve core 3213 is shown in a closed state in the valve cavity 3212. In the closed state, the valve core 3213 rotates in the valve cavity 3212 by a preset angle, such as the above-mentioned 20°.

[0133] like Fig.17As shown, when in the closed state, the outlet hole 321322 of the flow channel 32132 of the valve core 3213 is misaligned with the tapered extrusion port 32151, so that the outlet hole 321322 of the flow channel 32132 is blocked by the inner wall of the valve cavity 3212 to prevent the fluid material in the flow channel 32132 from flowing through the nozzle 3215. In this state, the fluid material from the extrusion channel 3214 keeps the fluid material filled in the sink 32133 between the valve core 3213 and the valve cavity 3212, so that the valve core 3213 is wrapped by the fluid material and is in a "suspended" state, and is kept between the valve core 3213 and the valve cavity 3212, so that the valve core 3213 is The valve core 3213 is almost wrapped by the fluid material, thereby avoiding direct mechanical contact between the valve core and the print head. Before the valve core 3213 needs to be switched to the open state next time, it is necessary to preheat the material reserved in the sink 32133 by the preset end heater 3216 and melt it into fluid material. The re-melted fluid material acts as a lubricant to a certain extent, so that when the valve core 3213 is rotated again, the valve core 3213 will be smoothly adjusted to the extrusion channel 3214 and the inlet hole 321321, flow channel 32132, outlet hole 321322 of the valve core 3213 and the tapered extrusion port of the nozzle are in a connected state.

[0134] In order to facilitate the instruction of the operator, in one embodiment, the second end of the shaft body 32131 is provided with an identification structure to indicate the open state and the closed state of the valve core 3212. The identification structure can be configured as at least one of a structural identification, a text identification, and a symbol identification, and the manner of being configured at the second end of the shaft body 32131 includes but is not limited to pasting, engraving, labeling, laser engraving, and a digital display screen. For example, the identification structure can be configured as "□", when the valve core 3212 is in an open state, the identification structure indicates an upright "□", and when the valve core 3212 is in a closed state, the identification structure indicates an inclined "◇". In this way, the operator can judge whether the valve core 3212 is in an open state or a closed state only according to the direction of the identification structure, so as to proceed to the next step. It should be noted here that the above example is only an exemplary description and should not be understood as a limitation of the present application. The identification structure can be configured in any form as long as it can indicate the operator.

[0135] As mentioned above, the sink 32133 is formed in the suspension section 321312 of the shaft body 32131 corresponding to the extrusion channel 3214. Fig.12 As shown, the width d1 of the sink 32133 is greater than or equal to the aperture d2 of the extrusion channel 3214. Fig.12In the illustrated embodiment, the aperture d2 of the extrusion channel 3214 is equal to the aperture d2 of the flow channel 32132, so that the molten fluid material can be quickly output from the extrusion channel 3214 to the flow channel 32132, and then flow from the conical inner cavity of the nozzle 3215 to the conical extrusion port 32151. Since the inlet holes 321321 of the flow channel 32132 are all located in the trough 32133, the width d1 of the trough 32133 needs to be greater than or equal to the aperture d2 of the extrusion channel 3214.

[0136] In one embodiment, the length of the top edge of the side wall of the sink 32133 is less than the surface perimeter of the shaft body 32131. The top edge of the side wall refers to the upper edge of the side wall where the sink 32133 and the shaft body 32131 meet. Fig.11 As shown, the top edge of the side wall of the groove 32133 partially overlaps with the surface of the shaft body 32131. As mentioned above, the groove 32133 only partially surrounds the shaft body 32131, so the length of the top edge of the side wall of the groove 32133 is less than the surface circumference of the shaft body 32131.

[0137] In one embodiment, if Fig.13 As shown, the angle β corresponding to the arc line of the top edge of the side wall of the trough 32133 is between 270° and 330°, for example, it can be approximately 270°, 280°, 290°, 300°, 310°, 320°, or 330°, etc., which is determined according to actual production needs and is not limited in this application.

[0138] In one embodiment, the inlet hole 321321 of the flow channel 32132 is located in the area with the largest groove depth of the sink 32133. When the molten fluid material is output from the extrusion channel 3214 to the flow channel 32132, the fluid material is filled into the sink 32133 from the connection between the extrusion channel 3214 and the inlet hole 321321. Specifically, the fluid material is first deposited at the inlet hole 321321, and then gradually diffused to other areas of the sink 32133. Therefore, when the inlet hole 321321 is located in the area with the largest groove depth of the sink 32133, the fluid material can be evenly diffused to the entire sink.

[0139] In one embodiment, the maximum groove depth d3 of the trough 32133 is less than or equal to the diameter d4 of the flow channel 32132. In one embodiment, the volume of the trough 32133 is greater than or equal to the volume of the flow channel 32132, so that the fluid material filled in the trough 32133 is greater than or equal to the fluid material filled in the flow channel 32132.

[0140] In one embodiment, if Fig.13As shown, the depth of the trough 32133 increases from one end of the outlet hole 321322 of the flow channel 32132 toward one end of the inlet hole 321321 of the flow channel 32132, and decreases after passing through the inlet hole 321321 of the flow channel 32132. That is to say, when the fluid material diffuses from the inlet hole 321321 of the flow channel 32132 from both sides to the entire trough 32133, the cross-sectional area of ​​the trough 32133 gradually decreases, and the fluid material can be filled in the trough 32133 at a faster speed.

[0141] In another embodiment, see Fig.18 , which is a cross-sectional view of a valve core in another embodiment of the present application, such as Fig.18 As shown, the sink 32133 increases in depth from one end of the outlet 321322 of the flow channel 32132 toward the other end. Of course, the sink 32133 can also be set to other shapes, which are determined according to actual production needs, and this application does not impose any restrictions on this.

[0142] In one embodiment, the length of the intersection of the sink 32133 and the flow channel 32132 is less than 1 / 2 of the aperture of the outlet hole 321322. Fig.18 For example, the aperture of the outlet hole 321322 is equal to the diameter d4 of the flow channel 32132, and the length of the intersection of the sink 32133 and the flow channel 32132 is expressed as d5. Fig.18 As shown, d5 is less than 1 / 2 of d4.

[0143] The following combination Figures 9 to 18 The switching of the valve core 3213 between the open state and the closed state is described in detail.

[0144] First, the end heaters 3216 disposed on both sides of the print head 321 preheat the reserved material in the print head 321 to melt it into a fluid material, so that the valve core 3213 is wrapped by the fluid material and is in a similar "suspended" state. According to the instructions of the printing program, the computer control system turns on the power source to act on the actuator, so that the first piston 32172 of the actuator 3217 moves linearly, driving the shaft body 32131 to rotate a certain angle, and the flow channel 32132 connects the extrusion channel 3214 and the tapered extrusion port 32151, and presents Fig.12 or Fig.16In this process, the feeding system 322 outputs the fluid material to the print head 321 through the feeding channel 323 via the access device 324, and the fluid material is heated again by the compensation heaters arranged at both ends of the access device 324 to ensure its flow state, and then the fluid material is output to the valve core 3213 through the extrusion channel 3214 perpendicular to the feeding channel 323, and while filling the sink 32133, it is output to the nozzle 3215 through the flow channel 32132 to realize the subsequent printing operation.

[0145] When it is necessary to stop conveying the fluid material, the computer control system will shut down the power source and act on the actuator according to the instruction of the printing program, so that the second piston 32173 of the actuator 3217 moves linearly in the opposite direction, driving the shaft body 32131 to rotate a certain angle in the opposite direction, so that the outlet hole 321322 of the flow channel 32132 is misaligned with the tapered extrusion port 32151, and presents Fig.14 or Fig.17 The closed state shown can prevent the fluid material from flowing through the nozzle 3215. When the fluid material needs to be delivered again, just repeat the above process.

[0146] To summarize, in order to overcome the technical problems in the related art that the valve mechanism is difficult to achieve complete closure of the print head, causing leakage of molten material and resulting in low printing accuracy, and that forced closure of the valve mechanism will cause damage to the print head, the melt extrusion device, 3D printing robot and 3D printing equipment provided in the present application are provided with a valve chamber for accommodating a valve core in the print head, and a flow channel radially penetrating the shaft body of the valve core and docking with the extrusion channel is provided in the valve core, so that the flow channel can achieve the open state of the valve core when the extrusion channel and the tapered extrusion port are connected, and the closed state of the valve core can be achieved when the outlet hole of the flow channel is misaligned with the tapered extrusion port on the print head nozzle, so as to control whether the fluid material can flow through the nozzle on the print head, thereby achieving normal opening and complete closing of the print head, avoiding leakage of fluid material, and thus ensuring printing accuracy. By arranging a partially surrounding groove on the shaft body of the valve core, the valve core can fill the groove with fluid material when it is in a closed state and maintain it between the valve core and the valve cavity, so that the valve core is wrapped by the fluid material, and the valve core is placed in a "suspended" state. This can prevent the valve core from being crushed to the inner wall of the valve cavity due to the thermal expansion of the fluid material when it is closed, avoid direct mechanical contact between the valve core and the print head, and avoid damage to the print head, thereby ensuring the smooth progress of the printing operation.

[0147] In addition, by arranging a melt extrusion device with a material storage device and a feeding system on the mechanical arm of the 3D printing robot, the caching and melting of the granular material are realized, and the transportation path of the molten fluid is shortened to a certain extent; furthermore, the present application realizes the short-path supply of the fluid material from the feeding channel to the nozzle of the print head by arranging a feeding channel for connecting the feeding system and the print head between the mechanical arm and the print head, and the present application designs a feeding channel with a stiffness smaller than that of the mechanical arm, and arranges the feeding channel between the fourth axis joint of the 3D printing robot and the print head, which not only ensures the flexibility of the movement of each mechanical arm of the robot during the printing process, but also can reduce the instantaneous pressure changes caused by the fluid material, thereby ensuring the uniform supply of the fluid material; and the present application arranges a temperature control device on the pipeline body of the feed channel, which can avoid the increase of viscosity of the fluid material due to heat loss or even cooling and stagnation during long-distance transportation, thereby avoiding the blockage of the fluid material in the pipeline body and the print head, ensuring the continuous supply of the fluid material, and thus improving the 3D printing efficiency and the printing quality of the object.

[0148] Furthermore, by arranging a first robot for printing 3D objects and a second robot for performing subtractive processing on 3D objects in the molding chamber, the integration of printing operations and subtractive processing is achieved, thereby avoiding the need to re-clamp and reposition the 3D objects and improving processing efficiency. By arranging the first robot and the second robot on the first side and the second side of a rotatable printing platform, while achieving a reasonable layout of the first robot and the second robot in the molding chamber, the first robot and the second robot can respectively perform printing and subtractive processing on 3D objects without changing position, thereby further improving processing efficiency.

[0149] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A melt extrusion device for a 3D printing robot, characterized in that: include: A feeding system, arranged on the mechanical arm of the 3D printing robot, for melting the granular material into a fluid material and outputting it through a feeding channel under pressure; A print head, comprising a valve cavity located in a print head body, a valve core arranged in the valve cavity, an extrusion channel connected to the feed channel, and a nozzle connected to the extrusion channel, wherein the nozzle comprises a tapered extrusion port for printing a fluid material; wherein the valve core comprises an axis body, radially penetrates the axis body and is used to connect to a flow channel of the extrusion channel, and a sink formed partially around the axis body; wherein the width of the sink is greater than or equal to the aperture of the extrusion channel; the length of the top edge of the side wall of the sink is less than the surface circumference of the axis body; the angle corresponding to the arc line of the top edge of the side wall of the sink is between 270° and 330°; The inlet holes of the flow channel are all located in the sink so that the fluid material from the extrusion channel can be filled into the sink, and the outlet hole of the flow channel is partially located in the sink; when the valve core is in an open state, the flow channel connects the extrusion channel and the tapered extrusion port so that the fluid material can flow through the nozzle; and when the valve core is in a closed state, the outlet hole of the flow channel is misaligned with the tapered extrusion port to prevent the fluid material from flowing through the nozzle, and the fluid material filled in the sink is kept between the valve core and the valve cavity.

2. The melt extrusion device according to claim 1, characterized in that: The feeding system is arranged on the mechanical arm between the third axis joint and the fourth axis joint of the 3D printing robot.

3. The melt extrusion device according to claim 1, characterized in that: The material supply system includes one or more heaters for heating and melting the material.

4. The melt extrusion device according to claim 1, characterized in that The melting temperature range of the heated material is 130°C to 240°C.

5. The melt extrusion device according to claim 1, characterized in that: The material feeding system includes one or more temperature sensors for detecting the temperature of the molten material.

6. The melt extrusion device according to claim 1, characterized in that: The material feeding system includes a pressure sensor for detecting the pressure of the material in the extrusion channel.

7. The melt extrusion device according to claim 1, characterized in that: The 3D printing robot is a six-axis industrial robot.

8. The melt extrusion device according to claim 1, characterized in that: An access device is disposed on the upper side of the print head and is arranged along a first direction to connect the feed channel and the extrusion channel. The pipeline of the access device connecting to the feed channel is arranged horizontally, and the pipeline of the access device connecting to the extrusion channel is arranged vertically.

9. The melt extrusion device according to claim 8, characterized in that: Compensation heaters for heating the fluid material passing through the access device are arranged at both ends of the access device.

10. The melt extrusion device according to claim 1, characterized in that: Terminal heaters for heating the fluid material in the print head are symmetrically arranged on both sides of the print head.

11. The melt extrusion device according to claim 10, characterized in that: Before the valve core switches from a closed state to an open state, the terminal heater preheats the reserved material in the print head to melt it into a fluid material.

12. The melt extrusion device according to claim 1, characterized in that: The print head is provided with a terminal temperature sensor for detecting the temperature of the fluid material in the print head.

13. The melt extrusion device according to claim 1, characterized in that: The nozzle comprises a conical inner cavity surrounded by a conical inner surface.

14. The melt extrusion device according to claim 1, characterized in that: The shaft body is disposed in the valve cavity in a second direction.

15. The melt extrusion device according to claim 14, characterized in that: The first end of the shaft body is connected to an actuator for driving the valve core to rotate so as to switch the valve core between an open state and a closed state.

16. The melt extrusion device according to claim 15, characterized in that: The actuator is disposed in the print head in a first direction perpendicular to the second direction and is movably connected to the first end of the shaft body.

17. The melt extrusion device according to claim 15, characterized in that: The actuator is a mechanical actuator.

18. The melt extrusion device according to claim 15, characterized in that The actuator is a pneumatic actuator.

19. The melt extrusion device according to claim 15, characterized in that: The actuator includes a slider and a piston fixedly arranged at both ends of the slider. The body of the slider is movably connected to the first end of the shaft body. The two ends of the piston are configured to move linearly in the slider when driven by air pressure to drive the shaft body to rotate.

20. The melt extrusion device according to claim 1, characterized in that The shaft body rotates between 15-45 degrees to switch the valve core between an open state and a closed state.

21. The melt extrusion device according to claim 20, characterized in that The second end of the shaft body is provided with an identification structure to indicate the open state and the closed state of the valve core.

22. The melt extrusion device according to claim 21, characterized in that The identification structure is at least one of a structural identification, a text identification, and a symbol identification.

23. The melt extrusion device according to claim 1, characterized in that The shaft body comprises two side shaft sections axially connected to the valve cavity and a suspension section located between the two side shaft sections; the flow channel and the sink groove are formed in the suspension section corresponding to the extrusion channel.

24. The melt extrusion device according to claim 1, characterized in that The inlet hole of the flow channel is located in the area where the groove depth of the sink is the largest.

25. The melt extrusion device according to claim 1, characterized in that The maximum groove depth of the sink is less than or equal to the diameter of the flow channel.

26. The melt extrusion device according to claim 1, characterized in that The volume of the trough is greater than or equal to the volume of the flow channel.

27. The melt extrusion device according to claim 1, characterized in that The sink groove has a tendency of increasing depth from one end of the outlet hole of the flow channel toward the other end.

28. The melt extrusion device according to claim 1, characterized in that The sink groove has a tendency of increasing depth from one end of the outlet hole of the flow channel toward one end of the inlet hole of the flow channel, and has a tendency of decreasing depth after passing through the inlet hole of the flow channel.

29. The melt extrusion device according to claim 1, characterized in that The length of the intersection of the trough and the flow channel is less than 1 / 2 of the aperture of the outlet hole.

30. A 3D printing robot, characterized in that: The 3D printing robot comprises the melt extrusion device as described in any one of claims 1-29.

31. A 3D printing device, characterized in that: include: A molding chamber, used to provide a closed molding space for 3D printing operations; A printing platform, rotatably disposed in the molding chamber for carrying a molded 3D object; A first robot is disposed on a first side of the printing platform, comprising a first robot arm that moves on the upper side of the printing platform according to a first movement path, and a print head disposed on the first robot arm for melting powder or granular material and depositing it on the printing platform according to the first printing path to form the 3D object layer by layer; wherein the first robot arm is provided with a melt extrusion device as described in any one of claims 1 to 29; The second robot is arranged on the second side of the printing platform and at a first preset angle with the first robot, and includes a second robot arm that moves on the upper side of the printing platform according to a second motion path, and a cutting component arranged on the second robot arm for performing subtractive processing on the 3D object deposited on the printing platform according to a subtractive path.

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