CN113333955A

CN113333955A - Narrow-spacing parallel wire feeding device for multi-wire additive manufacturing

Info

Publication number: CN113333955A
Application number: CN202110413524.3A
Authority: CN
Inventors: 都东; 李自祥; 蒲泽; 张昊宇
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-09-03

Abstract

The invention relates to the technical field of additive manufacturing, and provides a narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, which comprises a shell sleeve, wherein a plurality of wire feeding pipes arranged along the axial direction are arranged in the shell sleeve, and are annularly distributed around the central axis of the shell sleeve; the transition joint is arranged at the bottom end of the shell sleeve, a plurality of transition channels extending along the axial direction are arranged in the main body of the transition joint, the outlet end of each wire feeding pipe is communicated with the transition channel, the lower parts of the transition channels are all narrowed inwards to reduce the distance between the wire outlet ends of the transition channels, and the wire outlet ends of the transition channels are arranged in parallel; the wire feeding nozzle is arranged at the bottom end of the transition joint, a plurality of wire feeding channels which are arranged in parallel along the axial direction are arranged in the wire feeding nozzle, and the wire outlet end of each transition channel is communicated with a wire feeding channel. The device has simple structure and has obvious effects of reducing liquid drop splashing in the multi-wire additive manufacturing process and improving the quality and the performance of formed parts.

Description

Narrow-spacing parallel wire feeding device for multi-wire additive manufacturing

Technical Field

The invention relates to the technical field of additive manufacturing, in particular to a narrow-spacing parallel wire feeding device for multi-wire additive manufacturing.

Background

In the background of intelligent Manufacturing, the advent of Additive Manufacturing (AM) technology provides a new processing method for Manufacturing parts, which has received high attention from all countries since its emergence. Different from the traditional material reduction processing mode, the AM technology is based on a discrete accumulation principle, namely after the structural design of a part is completed through computer three-dimensional modeling software, the part is dispersed through layered software, path planning, support design and the like are assisted, then forming materials are accumulated layer by layer from points and lines to the surface, and finally forming and manufacturing of the part are completed. The AM technology belongs to a near-net forming technology, so the AM material has the advantages of high material utilization rate, short processing period, high production flexibility and the like, and is particularly suitable for small-batch customized processing production of parts.

As the AM technology with the most potential and application prospect, the metal additive manufacturing technology attracts the attention of researchers since the emergence. Metal additive manufacturing technologies mainly include laser, electron beam, and arc additive manufacturing technologies according to differences in heat sources, and include wire-feeding additive manufacturing technologies and powder-laying/powder-feeding additive manufacturing technologies according to differences in original consumables. Although the part manufactured by the powder type additive manufacturing technology has high forming precision, the formed sample part is generally small in size and low in deposition efficiency, and powder pollution and waste are serious due to the difficulty in recycling metal powder. Compared with the powder laying/powder feeding type additive manufacturing technology, the wire additive manufacturing technology has the advantages of high deposition efficiency, high material utilization rate, small limitation on processing size, high compactness of a formed part and the like, has incomparable advantages in the manufacturing of aerospace large-scale structural parts, and is particularly suitable for processing parts such as large-scale metal frames, rib plates and the like.

At present, the wire material additive manufacturing technology mainly uses single wire feeding as a main part, and the technology shows great advantages in the process of processing traditional difficult-to-process materials such as titanium alloy, nickel-based alloy, cobalt-based alloy and the like, so that rapid development is achieved in recent years. However, as the monofilament additive manufacturing technology becomes mature, the multi-filament additive manufacturing technology attracts the attention of more and more researchers, and the technology shows a huge application prospect in the aspects of material in-situ preparation of multi-component alloys and gradient parts and part manufacturing. The basic principle of in-situ preparation is to control the components of the formed part by controlling the feeding proportion of each wire material and control the shape of the part by controlling the moving track of a high-energy heat source, thereby achieving the purpose of material in-situ preparation-structure integration. However, the existing wire feeding modes are all separated wire feeding devices, and the separated wire feeding mode has the major disadvantages: on one hand, the mechanical structure is redundant, and the two wire feeders are easy to interfere in space, so that the two wires are difficult to adjust to proper positions; on the other hand, because the separated wire feeding mode enables each wire to have a certain angle and distance before entering a molten pool, each metal droplet is difficult to enter the molten pool simultaneously in the additive manufacturing process to generate a metallurgical reaction to generate an alloy to be prepared, and the droplet splashing is easily induced by the larger distance between the metal droplets, so that the macro segregation phenomenon of components generated in the part is further caused.

Therefore, in order to satisfy the requirement of high-quality in-situ forming in the multi-wire additive manufacturing process, a narrow-pitch parallel wire feeding device is needed to solve the problems of liquid drop splashing, uneven components and poor forming quality in the multi-wire additive manufacturing process.

Disclosure of Invention

The invention provides a narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, which is used for solving the defects of complex structure, easy splashing of liquid drops, poor forming quality and the like of a separated wire feeding device in the prior art.

The invention provides a narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, which comprises: the wire feeding device comprises a shell sleeve, wherein a plurality of wire feeding pipes are arranged in the shell sleeve along the axial direction, and are annularly distributed around the central axis of the shell sleeve; the transition joint is arranged at the bottom end of the shell sleeve, a plurality of transition channels extending along the axial direction are arranged in the main body of the transition joint, the outlet end of each wire feeding pipe is communicated with the transition channel, the lower parts of the transition channels are all inwards narrowed so as to reduce the distance between the wire outlet ends of the transition channels, and the wire outlet ends of the transition channels are arranged in parallel; the wire feeding nozzle is arranged at the bottom end of the transition joint, a plurality of wire feeding channels which are arranged in parallel along the axial direction are arranged in the wire feeding nozzle, and the wire outlet end of each transition channel is communicated with the wire feeding channels.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, the adjusting mechanism comprises a first bracket and a second bracket, a first end of the first bracket is slidably connected with the outer shell sleeve, and a second end of the first bracket is rotatably connected with the second bracket.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, a slide way is arranged in a main body at the first end of the first support, the outer shell sleeve penetrates through the slide way, and a first fastening piece is arranged on the outer wall of the first end of the first support and used for locking the outer shell sleeve; the second end of the first bracket is connected with the second bracket through a rotating piece.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, the top end of the shell sleeve is provided with the fastening end cover, the main body of the fastening end cover is internally provided with the guide hole for the wire feeding pipe to pass through, and the outer wall of the fastening end cover is provided with the second fastening piece for fixing the upper end of the wire feeding pipe.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, the outer wall of the fastening end cover is in clearance fit with the inner wall of the outer shell sleeve.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, the multi-wire specifically comprises double-wire, three-wire and more than three same-wire materials or different-wire materials.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, the main body of the transition joint is also internally provided with the installation channel, the installation channel is positioned above the transition channel and communicated with the transition channel, and the installation channel is arranged inside the bottom end of the outer shell sleeve and used for accommodating the outlet end of the wire feeding pipe.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, a third fastener is arranged on the outer wall of the mounting channel and used for fixing the outlet end of the wire feeding pipe; the transition joint is detachably connected with the shell sleeve through a fourth fastener.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, part of the main body of the wire feeding nozzle is located inside the bottom end of the transition joint and is detachably connected through the fifth fastening piece.

According to the narrow-spacing parallel wire feeding device for multi-wire additive manufacturing, provided by the invention, the spacing between the central axis of the wire inlet end of the transition channel and the central axis of the wire outlet end of the transition channel is 2-6 mm; the distance between the adjacent surfaces of the two adjacent wire feeding channels is 0.2-1.5 mm; the length of the outer shell sleeve is 100-150 cm.

According to the invention, the narrow-spacing parallel wire feeding device is used for a fuse wire additive manufacturing process using laser, electron beam or electric arc as a heat source.

The narrow-interval parallel wire feeding device for multi-wire additive manufacturing provided by the invention has the advantages that the multiple transition channels of the transition joint are narrowed to reduce the intervals of the wire outlet ends of the multiple transition channels, the wire outlet ends of the multiple transition channels are arranged in parallel, and the wire feeding channels arranged in parallel in the wire feeding nozzle ensure that all wires are fed into a molten pool in a narrow-interval parallel posture in the multi-wire additive manufacturing process, so that all metal droplets can enter the molten pool according to a preset position to perform a metallurgical reaction to generate an alloy to be prepared; compared with a separated wire feeding mode, the device can effectively reduce the splashing of liquid drops through the arrangement, so that the quality and the performance of the additive manufacturing part are further improved; in addition, the wire feeding device is simple in overall structure design and assembly, the plurality of wire feeding pipes are integrally designed, the spatial interference between the separated wire feeding devices is avoided, and the wire feeding device has the characteristics of convenience in adjustment, installation, disassembly and the like.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a cross-sectional view of a narrow-pitch parallel wire feeder for multi-wire additive manufacturing provided by the present invention;

FIG. 2 is a schematic structural view of a transition joint provided by the present invention;

FIG. 3 is an assembly view of the housing sleeve and adjustment mechanism provided by the present invention;

reference numerals:

1: a housing sleeve; 2: a wire feeding pipe; 3: a transition joint;

4: a transition passage; 41: a screw thread inlet end; 42: a screw outlet end;

5: a wire feeding nozzle; 51: a wire feeding channel; 6: a first bracket;

7: a second bracket; 8: a first fastener; 9: a rotating member;

10: tightly fixing the end cover; 11: a second fastener; 12: installing a channel;

13: a third fastener; 14: a fourth fastener; 15: a fifth fastener;

16: and connecting the bolts.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," "third," "fourth," and "fifth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. Specific meanings of the above terms in the embodiments of the present invention can be understood in specific cases by those of ordinary skill in the art.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

The narrow-pitch parallel wire feeder for multi-wire additive manufacturing of the present invention is described below with reference to fig. 1-3. It should be understood that the multi-filament of the present invention is meant to include filaments of two, three and more filaments, and the multi-filament is not limited to a specific type of filament, and may be selected according to the actual alloy to be prepared, and may be used in a variety of the same type of filament, or in a variety of different types of filaments. Also, fig. 1-3 schematically illustrate the wire feeder when dual wires are employed.

According to an embodiment of the present invention, as shown in fig. 1, the narrow-pitch parallel wire feeding device for multi-wire additive manufacturing provided by the present invention mainly includes: the device comprises a shell sleeve 1, a transition joint 3 and a wire feeding nozzle 5. Wherein, be equipped with many in the shell sleeve 1 and send silk pipe 2 along the axial setting, many send silk pipe 2 to encircle the cloth around the axis of shell sleeve 1. Transition joint 3 sets up in shell sleeve 1's bottom, is equipped with a plurality of transition passages 4 along axial extension in transition joint 3's the main part, and the exit end intercommunication of every send a pipe 2 has transition passage 4, and the lower part of a plurality of transition passages 4 all inwards narrows down to reduce the interval between a plurality of transition passages 4's the wire outlet end 42, and a plurality of transition passages 4's the wire outlet end 42 parallel arrangement. The wire feeding nozzle 5 is arranged at the bottom end of the transition joint 3, a plurality of wire feeding channels 51 arranged in parallel along the axial direction are arranged in the main body of the wire feeding nozzle 5, and the wire outlet end 42 of each transition channel 4 is communicated with the wire feeding channels 51. The axial direction of the present invention can be understood as the height direction of the whole device, in particular the top-down direction.

The plurality of transition channels 4 of the transition joint 3 are narrowed to reduce the distance between the wire outlet ends 42 of the plurality of transition channels 4, the wire outlet ends 42 of the plurality of transition channels 4 are arranged in parallel, and the wire feeding channels 51 arranged in parallel in the wire feeding nozzle 5 ensure that each wire is fed into a molten pool in a narrow-distance parallel posture in the multi-wire additive manufacturing process, so that metal droplets of each wire can enter the molten pool according to preset positions to generate a metallurgical reaction to generate an alloy to be prepared; in addition, the liquid drop splashing can be effectively reduced through the parallel structure arrangement of the narrow intervals, so that the quality and the performance of the additive manufacturing part are further improved; in addition, the wire feeding device is simple in overall structure design and assembly, the plurality of wire feeding pipes are integrally designed, the spatial interference between the separated wire feeding devices is avoided, and the wire feeding device has the characteristics of convenience in adjustment, installation, disassembly and the like.

It can be understood that the transition passage 4 in the transition joint 3 and the wire feeding passage 51 in the wire feeding nozzle 5 of the present invention are both circularly distributed around the central axis of the outer casing sleeve 1 by using the wire feeding pipe 2 as a spatial positioning reference point, so as to facilitate smooth wire feeding from top to bottom.

Furthermore, a plurality of wire feeding pipes 2 are arranged in parallel, and are used for enabling wires in the wire feeding pipes 2 to enter the transition joint 3 in a parallel posture and simultaneously combined with the parallel feeding posture, so that the technical effect can be further improved.

According to an embodiment of the present invention, as shown in fig. 3, the wire feeding device of the present invention further includes an adjusting mechanism, the adjusting mechanism includes a first bracket 6 and a second bracket 7, a first end of the first bracket 6 is slidably connected to the housing sleeve 1, specifically, a slide is disposed in a main body of the first end of the first bracket 6, and the housing sleeve 1 penetrates through the slide and can move back and forth in the slide to adjust a protruding length of the housing sleeve 1; and the outer wall of the first end of the first bracket 6 is provided with a first fastening piece 8, and the housing sleeve 1 can be locked by the first fastening piece 8 after the extension length is adjusted. The second bracket 7 is rotatably connected to a second end of the first bracket 6, specifically, the second end of the first bracket 6 is disposed on the second bracket 7 through a rotating member 9, and the second end of the first bracket 6 can rotate around the rotating member 9 to adjust the angle of the housing sleeve 1. The wire feeding device can adjust the wire feeding distance and angle of the wire feeding device through the adjusting mechanism, and optimizes the multi-wire additive manufacturing process.

The specific type of the rotating member 9 of the present invention is not particularly limited as long as it can function as a rotational connection, and in this example, the rotating member 9 is a bolt-nut pair.

According to the embodiment of the present invention, as shown in fig. 1 and 3, a fastening end cap 10 is provided at the top end of the housing sleeve 1, the same number of guide holes as the wire feeding pipes 2 are provided in the main body of the fastening end cap 10, so that the wire feeding pipes 2 can enter the housing sleeve 1 through the guide holes, and a second fastening member 11 is provided on the outer wall of the fastening end cap 10 for fixing the upper end of the wire feeding pipe 2 to prevent the wire feeding pipe 2 from freely moving due to a force.

And, the top of shell sleeve 1 is equipped with the holding tank that is used for installing holding end cover 10, and the inner wall of shell sleeve 1 and the outer wall clearance fit of the holding tank of holding end cover 10 to fix through fastening screw.

According to the embodiment of the invention, as shown in fig. 1 and 3, a mounting channel 12 is further arranged in the main body of the transition joint 3, the mounting channel 12 is positioned above the transition channel 4 and is communicated with the transition channel 4, and the mounting channel 12 is arranged in the bottom end of the housing sleeve 1 and is used for accommodating the outlet end of the wire feeding pipe 2 so as to position the wire feeding pipe 2 and further smoothly feed the wire into the transition channel 4.

Further, a third fastening member 13 is disposed on an outer wall of the installation channel 12 for fixing an outlet end of the wire feeding tube 2, so as to improve wire feeding stability.

Moreover, the transition joint 3 is detachably connected with the housing sleeve 1 through a fourth fastener 14, so that the transition joint is convenient to disassemble, assemble and replace.

According to an embodiment of the invention, the central axis of the thread inlet end 41 of the transition channel 4 is spaced from the central axis of the thread outlet end 42 of the transition channel 4 by 2-6mm, preferably by 3 mm.

The distance between adjacent surfaces of two adjacent wire feed channels 51 is 0.2-1.5mm, preferably 0.5 mm.

The length of the housing sleeve 1 is 100-150cm, preferably 120 cm.

According to the embodiment of the invention, part of the main body of the wire feeding nozzle 5 is positioned inside the bottom end of the transition joint 3, the outer wall of the bottom end of the transition joint 3 is provided with the fifth fastening piece 15, and the wire feeding nozzle 5 and the transition joint 3 can be detachably connected through the fifth fastening piece 15, so that the wire feeding nozzle is convenient to disassemble, assemble and replace.

Specific types of the first fastener 8, the second fastener 11, the third fastener 13, the fourth fastener 14, and the fifth fastener 15 of the present invention are not particularly limited as long as they can perform a fastening function, and in the embodiment of the present invention, they are fastening screws.

The size and shape of the transition joint 3 of the present invention are not particularly limited, and the transition joint 3 may be an integrally formed structure or a separate structure depending on the number of wires used, so as to facilitate the installation of the wires, and in one example, as shown in fig. 1 to 3, the transition joint 3 is conical, and when double wires are used, the transition joint 3 is divided into two completely symmetrical halves, i.e., the central angles of the halves are 180 °, and is connected by the connection bolt 16.

When three wires are used, the transition joint 3 is divided into three identical halves, namely, the circle center angle of each half is 120 degrees, when more wires are used, the process is repeated. It should be understood that the number of installation channels 12, transition channels 4 and wire feed channels 51 is the same as the number of wire feed tubes 2, i.e. each wire feed tube 2 corresponds to a set of installation channels 12, transition channels 4 and wire feed channels 51.

According to an embodiment of the invention, the wire feeder can be used in a fuse additive manufacturing process using laser, electron beam or electric arc as a heat source.

The embodiment of the present invention using the twin wire will be described in detail with reference to fig. 1 to 3. The two wire materials used in the present example are TC4 titanium alloy and 1070 aluminum alloy dissimilar welding wires, the diameters of which are both 2mm, the diameters of the two wire feeding channels 51 of the wire feeding nozzle 5 used are 2.2mm, respectively, so as to facilitate the wire material feeding, and the heat source used in the additive manufacturing process is an electron beam.

The inner diameter of the wire feeding pipe 2 is 8mm, and the outer diameter is 10 mm; the distance between the central axes of the two guide holes in the fastening end cover 10 is 10mm, namely, the two wires are in a parallel posture with the distance of 10mm before entering the transition joint 3; the distance between the central axis of the screw inlet end 41 of the transition passage 4 and the central axis of the screw outlet end 42 is 3 mm; the length of the housing sleeve 1 is 120 cm; the distance between adjacent surfaces of two adjacent wire feed channels 51 is 0.5 mm.

In this example, the specific assembly sequence is as follows: firstly, two wire feeding pipes 2 enter the housing sleeve 1 through the guide holes of the fastening end cover 10. Next, the front-rear position of the wire feed pipe 2 is adjusted to an appropriate position, and then the upper end position of the wire feed pipe 2 is fixed by the second fastening member 11 while the relative positions of the fastening end cap 10 and the housing sleeve 1 are fixed by the fastening screw. Thirdly, the conical transition joint formed by connecting the two halves of the transition joint 3 through the connecting bolt 16 is installed at the bottom end of the shell sleeve 1, the outlet end position of the wire feeding pipe 2 is fixed through a third fastener 13, the relative positions of the conical transition joint and the shell sleeve 1 are fixed through a fourth fastener 14, and then the wire feeding nozzle 5 is installed at the bottom of the conical transition joint through a fifth fastener 15. Finally, the housing sleeve 1 is mounted into the first bracket 6 and, via the turning piece 9, onto the second bracket 7 and adjusted to the optimum wire feed angle (30-60 °) and wire feed extension length (12-18 mm).

Compared with the existing separated double wire feeding mode, the double-wire implementation mode has the following advantages: firstly, the mechanical structure is simple and reliable, the spatial interference of the double-wire clamp of the separated wire feeding device is avoided, and the adjustment and the use are convenient. Secondly, the invention ensures that the two wires enter the molten pool in a narrow-spacing parallel posture in the additive manufacturing process, so that the two metal droplets can smoothly enter the molten pool according to the preset positions to generate metallurgical reaction to generate the alloy to be prepared. Finally, the invention is also beneficial to reducing the splashing of liquid drops, thereby further improving the compactness, the component uniformity and the mechanical property of the prepared alloy part.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A narrow-pitch parallel wire feeder for multi-wire additive manufacturing, comprising:

the wire feeding device comprises a shell sleeve, wherein a plurality of wire feeding pipes are arranged in the shell sleeve along the axial direction, and are annularly distributed around the central axis of the shell sleeve;

the transition joint is arranged at the bottom end of the shell sleeve, a plurality of transition channels extending along the axial direction are arranged in the main body of the transition joint, the outlet end of each wire feeding pipe is communicated with the transition channel, the lower parts of the transition channels are all inwards narrowed so as to reduce the distance between the wire outlet ends of the transition channels, and the wire outlet ends of the transition channels are arranged in parallel;

the wire feeding nozzle is arranged at the bottom end of the transition joint, a plurality of wire feeding channels which are arranged in parallel along the axial direction are arranged in the wire feeding nozzle, and the wire outlet end of each transition channel is communicated with the wire feeding channels.

2. The narrow-pitch parallel wire feeder for multi-wire additive manufacturing of claim 1, further comprising an adjustment mechanism comprising a first bracket and a second bracket, a first end of the first bracket being slidably coupled to the outer housing sleeve and a second end of the first bracket being rotatably coupled to the second bracket.

3. The narrow-spacing parallel wire feeding device for multi-wire additive manufacturing according to claim 2, wherein a slide is provided in the main body of the first end of the first bracket, the outer sleeve penetrates through the slide, and a first fastening member is provided on an outer wall of the first end of the first bracket for locking the outer sleeve; the second end of the first bracket is connected with the second bracket through a rotating piece.

4. The narrow-spacing parallel wire feeding device for multi-wire additive manufacturing according to claim 1, wherein a fastening end cover is arranged at the top end of the outer shell sleeve, a guide hole for the wire feeding pipe to pass through is formed in a main body of the fastening end cover, and a second fastening piece is arranged on the outer wall of the fastening end cover and used for fixing the upper end of the wire feeding pipe.

5. The narrow-pitch parallel wire feeder for multi-wire additive manufacturing of claim 1, wherein the multi-wire comprises two, three and more same or different wire materials.

6. The narrow-pitch parallel wire feeder for multi-wire additive manufacturing of claim 1, wherein a mounting channel is further disposed in the main body of the transition joint, the mounting channel is located above and in communication with the transition channel, and the mounting channel is disposed inside the bottom end of the outer sleeve for receiving the outlet end of the wire feeding tube.

7. The narrow-spacing parallel wire feeding device for multi-wire additive manufacturing according to claim 6, wherein a third fastener is arranged on an outer wall of the installation channel and used for fixing an outlet end of the wire feeding pipe; the transition joint is detachably connected with the shell sleeve through a fourth fastener.

8. The narrow-pitch parallel wire feed apparatus for multi-wire additive manufacturing of claim 1, wherein a portion of a body of the wire feed nozzle is located inside a bottom end of the transition joint and is removably connected by a fifth fastener.

9. The narrow-spacing parallel wire feeding device for multi-wire additive manufacturing according to claim 1, wherein a distance between a central axis of a wire inlet end of the transition channel and a central axis of a wire outlet end of the transition channel is 2-6 mm; the distance between the adjacent surfaces of the two adjacent wire feeding channels is 0.2-1.5 mm; the length of the outer shell sleeve is 100-150 cm.

10. The narrow-pitch parallel wire feeder for multi-filament additive manufacturing according to any one of claims 1-9, wherein the wire feeder is used in a fuse additive manufacturing process with a laser, electron beam, or arc as a heat source.