3D printing method

Abstract

The invention discloses a 3D printing method, and relates to the technical field of 3D printing. A control system is used for separating a part model into an additive manufacturing area and an injection molding / casting area, the additive manufacturing area is subjected to material deposition by a feeding forming system according to a layer-by-layer deposition mode, and injection molding / casting is started by an injection molding / casting forming system after the set number of layers is accumulated; the feeding forming system forms a shell in an additive manufacturing mode, the injection molding / casting forming system fills an inner cavity, the shell is formed in multiple steps according to the shape of a part model, and shell forming and inner cavity filling are controlled to be carried out alternately. The 3D printing method provided by the invention is particularly suitable for production of parts with large sizes and complex structures, the forming speed is higher than that of a traditional additive manufacturing process, the forming capacity of the complex structures is higher than that of traditional injection molding and casting, and the application range is very wide.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a 3D printing method. Background Art

[0002] At present, the technologies that can directly obtain irregular parts are mainly casting / injection molding technology and rapid prototyping technology. Casting / injection molding technology has been developed for a long time and can directly mold metal or plastic, but the production efficiency is too low and it is not suitable for the manufacture of complex parts. Injection molding, also known as injection molding, is a molding method that combines injection and molding. The advantages of the injection molding method are fast production speed, high efficiency, automated operation, a wide variety of colors, shapes from simple to complex, sizes from large to small, and precise product size. The product is easy to update and can be made into complex-shaped parts. Injection molding is suitable for mass production and molding processing fields such as complex-shaped products. At a certain temperature, the completely molten plastic material is stirred by a screw, injected into the mold cavity with high pressure, and cooled and solidified to obtain a molded product. This method is suitable for mass production of parts with complex shapes and is one of the important processing methods.

[0003] The casting process involves melting metal, making a mold, and pouring the molten metal into the mold. After solidification, metal parts with certain shapes, sizes, and properties are obtained. Metal mold casting, also known as hard mold casting, is a process of pouring liquid into a metal mold. Metal mold castings have good mechanical properties and high production efficiency, but the mold opening cost is expensive, and the wall thickness of the casting is required to be uniform and not too thin, which has limitations on the casting process.

[0004] The most popular additive manufacturing technology in rapid prototyping technology (commonly known as 3D printing) is a technical device that uses powdered or filamentary consumable materials as a basis for digital model files, and constructs objects by sintering or depositing materials layer by layer and printing layer by layer. In the past, 3D printing manufacturing technology was often used to manufacture models in the fields of mold manufacturing, industrial design, etc., and is now gradually being used for direct rapid manufacturing of products. Due to its unique production technology characteristics and wide range of applications, it is considered a revolution in production and manufacturing methods.

[0005] Powder bed additive manufacturing is based on selective sintering or cladding of powder on the powder bed. It has high precision, but low material utilization, slow molding speed and is limited by the size of the powder bed. Material deposition additive manufacturing process is based on wire feeding or powder feeding. Its molding speed has been improved to a certain extent, but the precision is poor, and large-sized parts are prone to deformation. It shows certain limitations when forming large-sized structural parts, and new technologies need to be developed to improve production efficiency and reduce production costs. Mainly include:

[0006] (1) Fused Deposition Modeling (FDM) is a technology that heats and melts various hot-melt filamentary materials (PLA, ABS, nylon, etc.) to form a shape.

[0007] (2) Wire and Arc Additive Manufacturing (WAAM) is a forming technology that uses electric arc as the energy beam and adopts a layer-by-layer welding method to manufacture metal solid components. The consumable material is metal welding wire.

[0008] (3) Laser Engineered Net Shaping (LENS), Laser Engineered Net Shaping technology is also called Laser Metal Deposition (LMD), Direct Metal Deposition (DMD), Direct Laser Fabrication (DLF), Laser Rapid Forming (LRF) technology. It is a forming technology that uses laser to generate a molten pool in the deposition area and continuously melts powder or filamentary materials to deposit layer by layer to generate a three-dimensional object. The consumable material is metal powder.

[0009] (4) Free Form, Arburg's unique injection molding 3D printing technology, melts the material through the injection principle, and then produces droplets through the nozzle. The droplets are continuously solidified layer by layer to produce plastic parts. The consumables are droplets plasticized from plastic particles.

[0010] Other additive manufacturing processes based on material deposition molding are not discussed here one by one. Material deposition molding often has a limited variety of materials, which is incomparable to injection molding or casting.

[0011] In summary, the current forming methods are difficult to adapt to the production of large-sized and complex-structured parts, and the forming efficiency needs to be further improved.

[0012] In view of this, the present invention is proposed. Summary of the invention

[0013] The purpose of the present invention is to provide a 3D printing method, which is intended to adapt to the production of large-sized and complex-structured parts while improving molding efficiency.

[0014] The present invention is achieved in that:

[0015] In a first aspect, the present invention provides a 3D printing method, comprising: the 3D printing device used comprises a control system, a feeding molding system, an injection molding / casting molding system and a printing platform;

[0016] The control system divides the part model into zones according to the part model, separates the part model into an additive manufacturing area and an injection molding / casting area, forms a slice file suitable for the feeding molding system and a filling area suitable for the injection molding / casting molding system, and controls the relative movement of the feeding molding system, the injection molding / casting molding system and the printing platform according to the path formed by the slices;

[0017] In the additive manufacturing area, the feed molding system deposits materials in a layer-by-layer deposition manner. After accumulating a set number of layers, the injection molding / casting molding system starts injection molding / casting. The feed molding system forms the shell by additive manufacturing, and the injection molding / casting molding system fills the inner cavity.

[0018] When partitioning is performed, the outer shell is formed in multiple steps according to the shape of the part model, and the outer shell forming and the inner cavity filling are controlled to be performed alternately.

[0019] In an optional embodiment, the partitioning is pre-judged in the molding direction according to the geometric features such as thickness, aspect ratio and the difficulty of injection molding / casting of different materials;

[0020] Areas with thickness less than the critical thickness are determined as additive manufacturing areas; for areas with narrow and long flow channels, they are filled by injection molding / casting in multiple stages.

[0021] In an optional embodiment, for metal part forming, the critical thickness is 2.5 mm-3.5 mm;

[0022] And / or, for plastic part molding, the critical thickness is 1.5mm-2.5mm.

[0023] In an optional embodiment, when the part model contains a suspended area, support is set for the suspended area, and the support is removed after molding is completed.

[0024] In an optional embodiment, the method further includes: removing the additive manufacturing area and retaining the internal injection molding / casting area;

[0025] Preferably, the additive manufacturing area is removed by pickling, electrochemical or physical treatment.

[0026] In an optional embodiment, for forming parts made of metal materials, the process adopted by the feeding forming system is selected from at least one of a coaxial powder feeding process, an arc fuse process and an inkjet printing process.

[0027] In an optional embodiment, for the molding of parts made of plastic material, the process adopted by the feeding molding system is selected from at least one of melt extrusion molding and liquid jet printing.

[0028] In an optional embodiment, the injection molding / casting molding system includes a containing chamber for containing consumables and a connecting structure connected to the containing chamber, so that the plasticized or melted consumable liquid flows into the inner cavity formed by the additive manufacturing method.

[0029] In an optional embodiment, when used for forming parts made of metal materials, the process adopted by the feeding forming system is coaxial powder feeding. The feeding forming system includes a laser and a powder feeding device. The metal powder fed by the powder feeding device is melt-coated on the previous layer or the printing platform by the laser; the injection molding / casting forming system is a casting system, including a casting port, a valve body and a metal bag. The metal bag is used to provide molten metal, and the valve body is used to regulate the rate at which the molten metal flows out of the casting port.

[0030] In an optional embodiment, when used for molding parts of plastic materials, the process adopted by the feeding molding system is melt extrusion molding. The feeding molding system includes a melt extrusion head, which is used to melt and extrude plastic filamentary consumables into filaments, and apply them layer by layer on the previous layer or the printing platform; the injection molding / casting molding system is an injection molding system, including an injection molding head, a screw plasticizer and a raw material cavity for holding plastic particles. The plastic particles are extruded through the screw plasticizer, and the injection molding area is injection molded through the injection molding head.

[0031] The present invention has the following beneficial effects: the present invention uses a control system to separate the part model into an additive manufacturing area and an injection molding / casting area. The additive manufacturing area is deposited by a feeding molding system in a layer-by-layer deposition manner. After accumulating a set number of layers, the injection molding / casting molding system starts injection molding / casting. The feeding molding system forms a shell by additive manufacturing, and the injection molding / casting molding system fills the inner cavity. The shell is formed in multiple steps according to the shape of the part model, and the shell forming and the inner cavity filling are controlled to be performed alternately. The 3D printing method provided by the present invention is particularly suitable for the production of large-sized and complex-structured parts. The molding speed is higher than that of the traditional additive manufacturing process. Its complex structure molding capability is higher than that of traditional injection molding and casting, and it has a very wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A diagram of a rapid prototyping device provided by an embodiment of the present invention;

[0034] Figure 2 A diagram of a rapid prototyping device in some embodiments;

[0035] Figure 3 A diagram of a rapid prototyping device in some other embodiments;

[0036] Figure 4 It is a schematic diagram of the principle of the rapid prototyping method;

[0037] Figure 5 is an example of the structural member in Embodiment 1;

[0038] Figure 6 The slicing and partitioning results of Example 1;

[0039] Figure 7 is a first process diagram of a 3D printing method;

[0040] Figure 8 is a second process diagram of the 3D printing method;

[0041] Fig. 9 A third process diagram of the 3D printing method;

[0042] Fig.10 is a fourth process diagram of the 3D printing method;

[0043] Fig.11 is a fifth process diagram of the 3D printing method;

[0044] Fig.12 is a sixth process diagram of the 3D printing method;

[0045] Fig.13 is a seventh process diagram of the 3D printing method;

[0046] Fig.14 is an eighth process diagram of the 3D printing method;

[0047] Fig.15 is a ninth process diagram of the 3D printing method;

[0048] Fig.16 This is the tenth process diagram of the 3D printing method.

[0049] Explanation of the main component symbols: 100-control system; 200-feeding molding system; 300-injection molding / casting molding system; 400-printing platform; 201-plastic filament consumables; 202-melting extruder; 203-laser; 204-powder feeding device; 301-injection molding head; 302-screw plasticizer; 303-raw material cavity; 304-casting port; 305-valve body; 306-metal bag. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0051] The embodiment of the present invention provides a 3D printing method, which uses Figure 1 The 3D printing device used in the 3D printing process includes a control system 100, a feeding molding system 200, an injection molding / casting molding system 300, and a printing platform 400. The control system 100 can control slicing according to the rapid prototyping part model, and control the relative movement of the feeding molding system 200, the injection molding / casting molding system 300, and the printing platform 400 according to the path formed by the slicing.

[0052] When used for forming parts made of metal materials, the process adopted by the feeding and forming system 200 is selected from at least one of the coaxial powder feeding process LENS, the arc fuse process WAAM and the inkjet printing process InkJet. That is to say, the feeding and forming system 200 can be a device commonly used by the existing LENS, WAAM, and InkJet processes, and a suitable 3D printing device is selected according to the requirements for the parts.

[0053] When used for molding parts made of plastic materials, the process adopted by the feeding molding system 200 is selected from at least one of melt extrusion molding FDM and liquid jet printing Free Form. The feeding molding system 200 can be a device commonly used by existing FDM and FreeForm, and a suitable 3D printing device is selected according to the requirements for the parts.

[0054] Specifically, LENS, WAAM, InkJet, FDM, and Free Form are all existing 3D printing processes, and the specific structures and operating principles of their equipment will not be repeated here.

[0055] like Figure 2 and Figure 3 As shown, the injection molding / casting molding system 300 includes a receiving chamber for receiving consumables and a connecting structure connected to the receiving chamber, so that the plasticized or melted consumable liquid flows into the inner cavity formed by the additive manufacturing method. The consumables in the receiving chamber can be metal consumables or non-metal consumables, and the connecting structure can be one or more, such as a nozzle, a cup mouth, etc., which can allow the plasticized or melted consumable liquid to flow into the molding space.

[0056] Specifically, the injection molding system uses the traditional plasticizing structure and adopts traditional plastic particles as consumables, and the casting molding system can use a heat-resistant material bag to receive the molten metal, and can pour the molten metal from the cup mouth or leak it from the bottom nozzle to achieve casting. The injection molding / casting molding system 300 can cooperate with the zoning method proposed in the present invention to calculate the physical properties such as the volume or weight of the filling material or calibrate the filling height, thereby controlling the amount of filling material. The printing platform 400 is equipped with the feeding molding system 200 and the injection molding / casting molding system 300, serving as the initial additive manufacturing substrate and the injection molding / casting mold surface.

[0057] In some embodiments, Figure 2 As shown, when used for forming parts of plastic materials, the process adopted by the feeding molding system 200 can be melt extrusion molding FDM, and the feeding molding system 200 includes a melt extrusion head 202, which is used to melt and extrude the plastic filament consumables 201 into filaments, and apply them layer by layer on the previous layer or the printing platform 400. The injection molding / casting molding system 300 is an injection molding system, including an injection molding head 301, a screw plasticizer 302 and a raw material cavity 303 for holding plastic particles. The plastic particles are extruded through the screw plasticizer 302, and the injection molding area is injection molded through the injection molding head 301. In this embodiment, the material of the printing platform 400 only needs to be not lower than the injection molding temperature, and preferably glass or aluminum is used.

[0058] In another embodiment, Figure 3 As shown, when used for forming parts made of metal materials, the process adopted by the feeding forming system 200 can be coaxial powder feeding LENS, and the feeding forming system 200 includes a laser 203 and a powder feeding device 204. The metal powder fed by the powder feeding device 204 is melted by the laser 203 on the previous layer or the printing platform 400, and is printed layer by layer. The injection molding / casting forming system 300 is a casting system, including a casting port 304, a valve body 305 and a metal bag 306. The metal bag 306 is used to provide molten metal, and the valve body 305 is used to regulate the rate at which the molten metal flows out of the casting port 304. The metal bag 306 can be a steel bag or an aluminum bag, which can provide a sufficient amount of molten metal. The flow rate of the molten metal flowing out of the casting port 304 can be controlled by the opening and closing time of the valve body 305, that is, the molten metal used for casting. In this embodiment, the melting point of the material of the printing platform 400 needs to be no lower than the melting point of the molten metal inside the casting forming system, and a high melting point metal substrate is preferably used.

[0059] Specifically, in the above embodiments, the feeding molding system 200 and the injection molding / casting molding system 300 can be interchangeable to be applicable to various parts production scenarios.

[0060] like Figure 4As shown, the 3D printing method provided by the embodiment of the present invention pre-processes the part model, and uses the control system 100 to divide the part model into zones, separate the part model into an additive manufacturing area and an injection molding / casting area, and form a slicing file suitable for the feeding molding system 200 and a filling area suitable for the injection molding / casting molding system 300. The feeding molding system 200, the injection molding / casting molding system 300 and the printing platform 400 are controlled to move relative to each other according to the path formed by the slicing, so that the positions of the feeding molding system 200, the injection molding / casting molding system 300 and the printing platform 400 correspond to each other, thereby completing the preset 3D printing and injection molding / casting molding process.

[0061] Furthermore, the additive manufacturing area is deposited by the feed molding system 200 in a layer-by-layer deposition manner. After a certain number of layers are accumulated (the number of layers may vary depending on the additive manufacturing process), the injection molding / casting molding system 300 starts injection molding / casting. The feed molding system 200 forms the outer shell by additive manufacturing, and the injection molding / casting molding system 300 fills the inner cavity. In order to adapt to the complex part morphology, when the partition is divided, the outer shell is formed in multiple steps according to the shape of the part model, and the outer shell forming and the inner cavity filling are controlled to be performed alternately. Figure 4 As shown, after the Nth layer is printed, the outer shell molding and the inner cavity filling are controlled to be performed alternately during the printing of the subsequent M layers until the part is formed.

[0062] The molding method provided by the embodiment of the present invention presets a certain or variable wall thickness based on the molding shape contour to ensure injection molding or casting of the filling area. When the part model contains a suspended area, support is set for the suspended area and the support is removed after molding is completed.

[0063] In some embodiments, the 3D printing method provided by the embodiments of the present invention, based on the above-mentioned preset shell, performs zoning prediction in the molding direction according to geometric features such as thickness, aspect ratio and the difficulty of injection molding / casting of different materials. The principle of prediction is based on the critical thickness required for filling. For example, for areas with a thickness less than the critical thickness (i.e., areas that are too thin and narrow), it is judged as an additive manufacturing area; for areas with narrow and long flow channels, it is necessary to divide the filling into multiple stages of injection molding / casting. For specific operations, please refer to Example 1.

[0064] Furthermore, for the forming of parts made of metal materials (such as aluminum alloy), the critical thickness is 2.5mm-3.5mm, such as 2.5mm, 2.8mm, 3.0mm, 3.2mm, 3.5mm, etc.; for the forming of parts made of plastic materials, the critical thickness is 1.5mm-2.5mm, such as 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, etc.

[0065] It should be noted that the molding method provided by the embodiment of the present invention can freely fill the same or different metals with a melting point not higher than the melting point of the high-melting-point metal, such as casting aluminum alloy in stainless steel, or casting cast iron or cast steel in a thicker stainless steel additive manufacturing profile; it can also freely fill non-metals in metals, such as injecting rubber into aluminum alloys to increase their mechanical properties; it can also fill the same or different non-metals with a melting point not higher than the melting point of high-melting-point non-metals, such as injection molding ABS into PMMA, etc. The molding speed of the molding method provided by the embodiment of the present invention is higher than that of the traditional additive manufacturing process, and its molding capacity of complex structures is higher than that of traditional injection molding and casting, and it has a wider range of applications.

[0066] In some embodiments, the post-processing process of the molding method provided by the embodiment of the present invention can also be varied. For example, the rapidly molded parts can be directly machined and used in products without any processing, or the additive manufacturing area can be removed and the internal injection molding / casting area can be retained. The method of retaining only the internal injection molding / casting area can be selected according to the structure of the part product to match the final morphology of the part product.

[0067] Furthermore, the additive manufacturing area can be removed by pickling, electrochemical or physical treatment, and the internal injection molding / casting area can be retained. For example, copper alloy is cast in stainless steel, and then the stainless steel layer is removed by pickling or chemical treatment, and the internal copper core is retained.

[0068] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0069] Example 1

[0070] This embodiment provides a 3D printing method, wherein the structure to be printed is as follows: Figure 5 As shown, the partition results are as follows Figure 6 shown.

[0071] The parts are made of polymer materials such as PLA, ABS, PEEK, and PA. The process used by the feeding molding system 200 can be melt extrusion, particle extrusion, or inkjet or a combination of the two. The injection molding / casting molding system 300 is an injection molding system. The 3D printing device is shown in FIG. Figure 2 shown.

[0072] The parts are made of aluminum alloy, stainless steel, titanium alloy, high temperature alloy and other metal materials. The process used by the feeding molding system 200 can be arc fuse, laser fuse, plasma arc fuse, electron beam fuse or coaxial powder feeding or a combination of the two. The injection molding / casting molding system 300 is a casting system. The 3D printing device is shown in FIG. Figure 3 shown.

[0073] The molding steps are as follows:

[0074] (1) Figure 7 As shown, due to some thin-wall structures, the filling method cannot be used, so feeding printing is adopted to print the bottom wall first.

[0075] (2) Figure 8 As shown, the edge wall is continued to be printed on the basis of the bottom wall, and the printing height corresponds to the height of the right side. When printing to this layer, the right side can be filled. Generally, in order to avoid interference, it is preferred to complete the injection molding at this time, see step (3).

[0076] (3) Fig. 9 As shown, the injection molding / casting filling of the right area is completed.

[0077] (4) Fig.10 As shown, after cooling, continue feeding and printing. Since a suspended layer appears at the top, injection molding / casting filling begins at the bottom.

[0078] (5) Fig.11 As shown, continue feeding and printing, and use 3D printing process support for the suspended layer.

[0079] (6) Fig.12 As shown, due to the thin walls and gaps in the subsequent layers, the injection molding / casting filling is completed at this layer.

[0080] (7) Fig.13 As shown, continue to print the thin walls and other structures of the upper layer.

[0081] (8) Fig.14 As shown, the injection molding is completed due to the appearance of partitions.

[0082] (9) Fig.15 As shown, due to the narrow and long flow channel, this section of injection molding is completed first.

[0083] (10) Fig.16 As shown, continue printing and complete the final injection molding.

[0084] The structure of the parts printed in this embodiment is relatively complex. The size ratio of each part of the part is as follows: Figure 5 .

[0085] In other embodiments, the 3D printing slicing method can output multiple 3D printing solutions for users to choose from based on geometric features such as minimum wall thickness and aspect ratio, taking into account process difficulty and molding efficiency.

[0086] Comparative Example 1

[0087] A conventional 3D printing process is used, namely the feeding molding system 200 in Example 1.

[0088] The results show that if a 10 kg stainless steel part is printed entirely with metal powder, it would take at least 2 days to print. This can be shortened to a few hours with this device.

[0089] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A 3D printing method, characterized in that: include: The 3D printing device used includes a control system, a feeding molding system, an injection molding / casting molding system and a printing platform; The control system divides the part model into zones according to the part model, separates the part model into an additive manufacturing area and an injection molding / casting area, forms a slicing file suitable for the feeding molding system and a filling area suitable for the injection molding / casting molding system, and controls the relative movement of the feeding molding system, the injection molding / casting molding system and the printing platform according to the path formed by the slicing; The additive manufacturing area is deposited by the feed molding system in a layer-by-layer deposition manner, and after accumulating a set number of layers, the injection molding / casting molding system starts injection molding / casting, the feed molding system forms the shell by additive manufacturing, and the injection molding / casting molding system fills the inner cavity; When partitioning is performed, the outer shell is formed in multiple steps according to the shape of the part model, and the outer shell forming and the inner cavity filling are controlled to be performed alternately.

2. The 3D printing method according to claim 1, characterized in that: In the molding direction, the zoning is predicted based on the geometric features and the difficulty of injection molding / casting of different materials; Areas with thickness less than the critical thickness are determined as additive manufacturing areas; for areas with narrow and long flow channels, they are filled by injection molding / casting in multiple stages.

3. The 3D printing method according to claim 2, characterized in that: For metal parts forming, the critical thickness is 2.5mm-3.5mm; And / or, for molding of parts made of plastic material, the critical thickness is 1.5 mm-2.5 mm.

4. The 3D printing method according to any one of claims 1 to 3, characterized in that: When the part model contains a suspended area, support is set for the suspended area, and the support is removed after molding is completed.

5. The 3D printing method according to claim 4, characterized in that: Also includes: Remove the additive manufacturing area and retain the internal injection molding / casting area; Preferably, the additive manufacturing area is removed by pickling, electrochemical or physical treatment.

6. The 3D printing method according to claim 1, characterized in that: For forming parts made of metal materials, the process adopted by the feeding forming system is selected from at least one of a coaxial powder feeding process, an arc fuse process and an inkjet printing process.

7. The 3D printing method according to claim 1, characterized in that: For the molding of parts made of plastic material, the process adopted by the feeding molding system is selected from at least one of melt extrusion molding and liquid jet printing.

8. The 3D printing method according to claim 1, characterized in that: The injection molding / casting molding system includes a containing chamber for containing consumables and a communicating structure communicating with the containing chamber, so that plasticized or melted consumable liquid flows into an inner cavity formed by additive manufacturing.

9. The 3D printing method according to claim 8, characterized in that: When used for forming parts made of metal materials, the process adopted by the feeding forming system is coaxial powder feeding. The feeding forming system includes a laser and a powder feeding device. The metal powder fed by the powder feeding device is melted by the laser onto the previous layer or the printing platform; the injection molding / casting forming system is a casting system, including a casting port, a valve body and a metal bag. The metal bag is used to provide molten metal, and the valve body is used to regulate the rate at which the molten metal flows out of the casting port.

10. The 3D printing method according to claim 8, characterized in that: When used for molding parts made of plastic materials, the process adopted by the feeding molding system is melt extrusion molding. The feeding molding system includes a melt extrusion head, which is used to melt and extrude plastic filamentary consumables into filaments, and apply them layer by layer on the previous layer or the printing platform; the injection molding / casting molding system is an injection molding system, including an injection molding head, a screw plasticizer and a raw material cavity for holding plastic particles. The plastic particles are extruded through the screw plasticizer, and the injection molding area is injection molded through the injection molding head.

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