CN106903313B

CN106903313B - Selective laser melting device and 3D printer

Info

Publication number: CN106903313B
Application number: CN201710237612.6A
Authority: CN
Inventors: 窦鹤鸿
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-04-12
Filing date: 2017-04-12
Publication date: 2020-01-31
Anticipated expiration: 2037-04-12
Also published as: WO2018188384A1; CN106903313A

Abstract

The invention relates to the technical field of 3D printing of metal molten in a laser selective area, in particular to laser selective area melting devices and a 3D printer, wherein each laser selective area melting device comprises a fixed part, a movable part and a moving mechanism, the movable part is connected with the fixed part in a sliding manner, the moving mechanism is connected with the movable part and used for driving the movable part to move relative to the fixed part along the circumferential direction, the movable part is used for mounting a laser coupling and excitation mechanism of the 3D printer, the moving mechanism drives the movable part to drive the laser coupling and excitation mechanism to move and work, and a user can control the diameter of a motion track of the laser coupling and excitation mechanism according to the size of a component, so that the moving range of the laser coupling and excitation mechanism is , the laser coupling and excitation mechanism is not limited by the deflection angle of a laser galvanometer, the range of a laser beam irradiating a metal powder layer is large, the size of a cylindrical component formed by technological equipment is large, and the technological equipment is favorable for pushing and.

Description

Selective laser melting device and 3D printer

Technical Field

The invention relates to the technical field of 3D printing of selective laser melting metal, in particular to selective laser melting devices and a 3D printer.

Background

The additive manufacturing 3D printing technology is a construction technology that materials such as powdered metal, PVC, resin, fiber and the like are used as a basis, a CAD three-dimensional configuration object is subjected to dimension reduction slicing through special software in the modes of fused deposition, laser sintering, laser melting, laser solidification and laser cladding, and then the object is printed layer by layer according to slices, wherein the construction technology is new technologies which are rapidly developing in the manufacturing industry and is which is an important mark of the third industrial revolution in the British journal of economic academy people (third industrial revolution) .

The 3D printing technology for melting metal in selective laser areas is characterized in that a high-energy-density laser beam is used for scanning under the control of a computer program, a metal powder layer which is laid in advance is selectively melted and is combined with matrix metallurgy, then powder is continuously laid, scanned and melted layer by layer, and finally the manufacturing process of three-dimensional metal parts is completed.

In the prior art, a laser beam of a selective laser melting metal 3D printer is reflected to a metal powder layer through a laser galvanometer to be selectively melted, and the position of the metal powder layer irradiated by the laser beam is adjusted by adjusting the deflection angle of the laser galvanometer so as to melt the metal powder layer at different positions.

According to known data, the maximum size of a component formed by using laser selective area melting process equipment in the world is about 4 hundred million yuan, wherein the scientific and technological attacking expenditure of the two laser selective area melting process equipment is 3850.00 ten thousand yuan, the is technical equipment with the attacking size range of more than or equal to 500mm x 500mm, and the implementation period of the project is 5 years.

Disclosure of Invention

The invention aims to provide laser selective melting devices and 3D printers, which are used for solving the technical problem that the diameter of a formed cylindrical component is small in the prior art.

The laser selective melting devices comprise fixing portions, moving portions and moving mechanisms, wherein the moving portions are connected with the fixing portions in a sliding mode, the moving mechanisms are connected with the moving portions and used for driving the moving portions to move relative to the fixing portions in the circumferential direction, the moving mechanisms are used for being electrically connected with a control system of a 3D printer, the moving portions are used for installing laser coupling and excitation mechanisms of the 3D printer, and the fixing portions are used for being fixedly connected with a box body of the 3D printer.

, the movable part comprises a movable part and a mounting part, the mounting part is fixedly connected with the movable part, the mounting part is used for mounting a laser coupling and excitation mechanism of the 3D printer, the movable part is connected with the fixed part in a sliding mode, and the moving mechanism is connected with the movable part and used for driving the movable part to do circular motion relative to the fixed part.

, the movable part comprises a movable part, an installation part and a rotating mechanism, the installation part is rotatably connected with the movable part, the rotating mechanism is connected with the installation part and used for driving the installation part to rotate relative to the movable part, the rotating mechanism is used for being electrically connected with a control system of the 3D printer, the installation part is used for installing a laser coupling and excitation mechanism of the 3D printer, the movable part is slidably connected with the fixed part, and the moving mechanism is connected with the movable part and used for driving the movable part to do circular motion relative to the fixed part.

, the fixed part is a circular ring-shaped slide rail, the moving part comprises a moving base, and the moving base is connected with the slide rail in a sliding manner.

, the slide rail comprises a plurality of circular arc sub-rails which are connected in sequence to form a circular ring shape, the movable base comprises a plurality of sub-bases, the movable mechanism comprises a plurality of movable structures, and the mounting part comprises a plurality of sub-mounting seats;

the multiple sub-bases are arranged corresponding to the multiple sub-rails , each sub-base is connected with sub-rails in a sliding mode, the multiple sub-mounting bases are fixedly connected with the multiple sub-bases correspondingly, and each sub-mounting base is used for mounting a laser coupling and excitation mechanism of a 3D printer;

a plurality of the moving structures are arranged corresponding to the plurality of the sub-bases , and each of the moving structures is connected with of the sub-bases and is used for driving the sub-bases to slide along the extending direction of the sub-rail.

, the moving element comprises an inner side pulley and an outer side pulley, the inner side pulley is rotatably connected with the end of the moving base close to the inner ring of the sliding rail, the outer side pulley is rotatably connected with the end of the moving base close to the outer ring of the sliding rail, and the inner side pulley and the outer side pulley are both vertically arranged and are both abutted to the sliding rail.

, the diameter of the outer side pulley is larger than that of the inner side pulley, an outer side sliding groove and an inner side sliding groove which are both annular are sequentially arranged on the sliding rail at intervals along the direction from the outer ring to the inner ring, the outer side pulley is arranged in the outer side sliding groove, the inner side pulley is arranged in the inner side sliding groove, the depth of the inner side sliding groove is smaller than that of the outer side sliding groove, and the depth difference between the inner side sliding groove and the outer side sliding groove is the same as the difference between the radius of the outer side wheel and the radius of the inner side wheel.

, a transverse limiting structure is arranged on the movable base and is used for preventing the movable base from moving along the width direction of the slide rail.

, the transverse limiting structure comprises an outer stabilizing structure wheel and an inner stabilizing structure wheel which are rotatably connected with the movable base, the outer stabilizing structure wheel and the inner stabilizing structure wheel are horizontally arranged, the outer stabilizing structure wheel is located at the end of the movable base close to the outer ring of the slide rail, the inner stabilizing structure wheel is located at the end of the movable base close to the inner ring of the slide rail, and the outer stabilizing structure wheel and the inner stabilizing structure wheel are respectively abutted to the outer ring side wall and the inner ring side wall of the slide rail.

, the invention also provides kinds of 3D printers, and the 3D printers comprise the selective laser melting device.

The invention provides a selective laser melting device which comprises a fixed part, a movable part and a moving mechanism. When the laser printer is used, the movable part is provided with the laser coupling and excitation mechanism of the 3D printer, the fixed part is fixedly connected to the box body of the 3D printer, and the moving mechanism is electrically connected with the control system of the 3D printer. The control system of the 3D printer controls the moving mechanism, the moving mechanism drives the moving part to do circular motion relative to the fixed part, meanwhile, the laser coupling and excitation mechanism does circular motion, and the laser beams irradiate the metal powder layer to be melted, so that the cylindrical component is manufactured.

According to the selective laser melting device provided by the invention, the moving mechanism drives the movable part to drive the laser coupling and excitation mechanism to move and work, and a user can control the diameter of the movement track of the laser coupling and excitation mechanism according to the size requirement of a component, so that the moving range of the laser coupling and excitation mechanism is relatively large and is not limited by the deflection angle of the laser galvanometer, the range of laser beams irradiating a metal powder layer is relatively large, the size of a cylindrical component formed by technological equipment is relatively large, and the of the technological equipment and the equipment in the world and the application of the technological equipment are facilitated.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in 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 embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of a selective laser melting apparatus according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a sub-track according to an embodiment of the present invention;

FIG. 3 is a schematic view of another configuration of the selective laser melting apparatus according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a moving part according to an embodiment of the present invention.

Reference numerals:

1-a stationary part; 2-a movable part; 3-an outer pulley;

4-inside pulley; 5-outer side sliding groove; 6-inner side sliding groove;

7-an external stabilizing structure wheel; 8-internal stabilization structure wheel; 11-a slide rail;

111-sub-track; 21-a moving member; 211-submount;

12-outer ring side wall; 13-inner ring side wall; 22-mounting member.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are partial embodiments, but not all embodiments .

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that unless otherwise specifically stated or limited, the terms "mounted," "connected," and "connected" are used to mean, for example, either fixedly or removably connected or physically connected, mechanically or electrically connected, directly or indirectly connected through an intermediary, or communicating between two elements.

Fig. 1 is a schematic structural diagram of a selective laser melting device according to an embodiment of the present invention, fig. 3 is another schematic structural diagram of the selective laser melting device according to the embodiment of the present invention, and as shown in fig. 1 and fig. 3, the selective laser melting device according to the embodiment of the present invention includes a fixed portion 1, a movable portion 2, and a moving mechanism, wherein the movable portion 2 is slidably connected to the fixed portion 1, the moving mechanism is connected to the movable portion 2 and is configured to drive the movable portion 2 to move in a circumferential direction relative to the fixed portion 1, the moving mechanism is configured to be electrically connected to a control system of a 3D printer, the movable portion 2 is configured to mount a laser coupling and excitation mechanism of the 3D printer, and the fixed portion 1 is configured to be fixedly connected to a box of the 3D printer.

The selective laser melting device provided by the embodiment of the invention comprises a fixed part 1, a movable part 2 and a moving mechanism. When the laser printer is used, the movable part 2 is provided with a laser coupling and excitation mechanism of the 3D printer, the fixed part 1 is fixedly connected to a box body of the 3D printer, and the moving mechanism is electrically connected with a control system of the 3D printer. The control system of the 3D printer controls the moving mechanism, the moving mechanism drives the movable part 2 to do circular motion relative to the fixed part 1, meanwhile, the laser coupling and excitation mechanism does circular motion, and laser beams irradiate on the metal powder layer to be melted, so that the cylindrical component is manufactured.

According to the selective laser melting device provided by the embodiment of the invention, the moving mechanism drives the moving part 2 to drive the laser coupling and excitation mechanism to move and work, a user can control the diameter of the movement track of the laser coupling and excitation mechanism according to the size requirement of a component, so that the moving range of the laser coupling and excitation mechanism is relatively large and is not limited by the deflection angle of the laser galvanometer, the range of laser beams irradiating a metal powder layer is relatively large, the size of a cylindrical component formed by technological equipment is relatively large, and the process technology and the equipment thereof are beneficial to the pushing and application in the world.

The moving mechanism may be in various forms, for example, the moving mechanism includes a motor, an external gear, an internal gear engaged with the external gear, and a central gear engaged with the internal gear. The outer gear is fixed on the fixing part 1, the central gear is rotationally connected on the fixing part 1, and the central gear is located at the center of the outer gear. The movable part 2 is fixed on the internal gear, and the motor is fixedly connected with the central gear. When the electric motor is used, the motor drives the central gear to rotate, the central gear drives the inner gear to rotate along the outer gear, and therefore the movable portion 2 is driven to move along the outer gear to do circular motion.

As another example, the moving mechanism includes a motor and a turntable. The turntable is rotatably connected with the fixed part 1, meanwhile, the turntable is fixedly connected with the motor, and the movable part 2 is fixedly arranged at the edge of the turntable. When the rotary table is used, the motor drives the rotary table to rotate, and the movable part 2 makes circular motion around the center of the rotary table.

As shown in fig. 3, based on the above embodiment, in step , the movable part 2 includes a moving part 21 and a mounting part 22, the mounting part 22 is fixedly connected with the moving part 21, the mounting part 22 is used for mounting a laser coupling and excitation mechanism of the 3D printer, the moving part 21 is slidably connected with the fixed part 1, and the moving mechanism is connected with the moving part 21 and is used for driving the moving part 21 to make a circular motion relative to the fixed part 1.

In this embodiment, set up movable part 2 into moving member 21 and installed part 22, installed part 22 and moving member 21 fixed connection, installed part 22 are used for installing the laser coupling and the excitation mechanism of 3D printer, set up like this, and laser coupling and excitation mechanism only do circular motion along with installed part 22 relative fixed part 1, make things convenient for the installation of laser coupling and excitation mechanism.

On the basis of the above embodiment, , the movable part 2 includes a movable part 21, a mounting part 22 and a rotating mechanism, wherein the mounting part 22 is rotatably connected with the movable part 21, the rotating mechanism is connected with the mounting part 22 and used for driving the mounting part 22 to rotate relative to the movable part 21, the rotating mechanism is used for being electrically connected with a control system of the 3D printer, the mounting part 22 is used for mounting a laser coupling and excitation mechanism of the 3D printer, the movable part 21 is slidably connected with the fixed part 1, and the moving mechanism is connected with the movable part 21 and used for driving the movable part 21 to make a circular motion relative to the fixed part 1.

In this embodiment, with installed part 22 and moving member 21 rotation connection, slewing mechanism drive installed part 22 rotates, that is, laser coupling and excitation mechanism relative movement member 21 rotate, and at this moment, laser coupling and excitation mechanism can be when doing circular motion relative movement member 21 rotates for laser coupling and the more of the coverage of excitation mechanism's light beam, more facilitate the use.

As shown in fig. 1, in the above embodiment, , the fixing portion 1 is a circular ring-shaped slide rail 11, the moving member 21 includes a moving base, and the moving base is slidably connected to the slide rail 11.

In this embodiment, the fixing portion 1 is configured as a circular slide rail 11, the slide rail 11 can guide the moving base to move along a predetermined direction, and the circular shape can reduce the weight of the fixing portion 1.

The slide rail 11 may be an -type structure or a split-type structure.

Fig. 2 is a schematic structural diagram of a sub-rail according to an embodiment of the present invention, and as shown in fig. 1 and fig. 2, on the basis of the above embodiment, steps are further performed, where the slide rail 11 includes a plurality of sub-rails 111 in an arc shape, the plurality of sub-rails 111 are connected in sequence to form a circular ring shape, the moving base includes a plurality of sub-bases 211, the moving mechanism includes a plurality of moving structures, the mounting device 22 includes a plurality of sub-mounts, the plurality of sub-bases 211 are disposed corresponding to the plurality of sub-rails 111 , each sub-base 211 is slidably connected to the sub-rails 111, the plurality of sub-mounts are fixedly connected to the plurality of sub-bases 211 , each sub-mount is configured to mount a laser coupling and excitation mechanism of a 3D printer, the plurality of moving structures are disposed corresponding to the plurality of sub-bases 211 , and each moving structure is connected to the sub-base 211 and configured to drive the sub-bases 211 to slide along.

In this embodiment, a plurality of sub-rails 111 are spliced to form the slide rail 11, sub-bases 211 are slidably disposed on each sub-rail 111, sub-mounts are connected to each sub-base 211, and laser coupling and excitation mechanisms are mounted on each sub-mount, so that the plurality of laser coupling and excitation mechanisms can simultaneously slide on the corresponding sub-rails 111 to perform a melting operation.

In this embodiment, the arrangement of the sub-rails 111 and the sub-mounts enables the laser coupling and excitation mechanisms to work simultaneously, thereby improving the efficiency of melting and processing the components.

Fig. 4 is a schematic structural diagram of a moving part according to an embodiment of the present invention, and as shown in fig. 3 and 4, in step , on the basis of the above embodiment, the moving member 21 includes an inner pulley 4 and an outer pulley 3, the inner pulley 4 is rotatably connected to the moving base at a end near the inner ring of the sliding rail 11, the outer pulley 3 is rotatably connected to the moving base at a end near the outer ring of the sliding rail 11, and both the inner pulley 4 and the outer pulley 3 are vertically disposed and are abutted to the sliding rail 11.

In this embodiment, the inner pulley 4 and the outer pulley 3 are disposed on the moving base, and the moving friction between the moving base and the fixing portion 1 is converted into rolling friction through the inner pulley 4 and the outer pulley 3, so that the friction force and the friction loss are reduced, and the service life of the moving base is prolonged.

As shown in fig. 3, in the above embodiment, the diameter of the outer pulley 3 is larger than that of the inner pulley 4 by steps, the outer sliding groove 5 and the inner sliding groove 6 which are both circular are sequentially arranged on the slide rail 11 along the direction from the outer ring to the inner ring at intervals, the outer pulley 3 is arranged in the outer sliding groove 5, the inner pulley 4 is arranged in the inner sliding groove 6, the depth of the inner sliding groove 6 is smaller than that of the outer sliding groove 5, and the depth difference between the inner sliding groove 6 and the outer sliding groove 5 is the same as the difference between the radius of the outer wheel and the radius of the inner wheel.

In this embodiment, the depth difference between the inner chute 6 and the outer chute 5 and the difference between the radius of the outer wheel and the radius of the inner wheel are set to be the same, so that the rotating shaft of the inner pulley 4 is flush with the rotating shaft of the outer pulley 3, and at this time, the movable base can be kept in a horizontal state, thereby preventing the movable base from inclining.

Wherein, the inner pulley 4 and the outer pulley 3 in the embodiment are respectively and independently connected with the mobile base in a rotating way. The inner sheave 4 and the outer sheave 3 may be two, respectively. The four pulleys support the moving base, so that the stability of the moving base can be improved.

On the basis of the above embodiment, , the movable base is provided with a lateral limiting structure, and the lateral limiting structure is used for preventing the movable base from moving along the width direction of the sliding rail 11.

In this embodiment, set up horizontal limit structure on mobile base, at mobile base circular motion's in-process, horizontal limit structure can prevent that mobile base from removing along the width direction of slide rail 11, also promptly, can prevent that mobile base from rocking about the width direction of slide rail 11, and step-by-step improvement mobile base's stability advances to improve laser coupling and the accurate preset position that shines of excitation mechanism light beam, improve the precision of manufacturing.

Wherein, horizontal limit structure's structural style can be multiple, for example, horizontal limit structure includes the stopper, stopper and moving base fixed connection, the left end and the right-hand member of stopper respectively with the outer lane lateral wall 12 of slide rail 11 and inner circle lateral wall 13 butt. The outer ring side wall 12 and the inner ring side wall 13 of the slide rail 11 exert acting force with the limiting block respectively, and the limiting block is limited in the transverse direction, so that the movable base is limited in the transverse direction.

Based on the above embodiment, as shown in fig. 3 and 4, in step , the lateral limiting structure includes an outer stabilizing structure wheel 7 and an inner stabilizing structure wheel 8 both rotatably connected to the moving base, the outer stabilizing structure wheel 7 and the inner stabilizing structure wheel 8 are both horizontally disposed, the outer stabilizing structure wheel 7 is located at the end of the moving base close to the outer ring of the slide rail 11, the inner stabilizing structure wheel 8 is located at the end of the moving base close to the inner ring of the slide rail 11, and the outer stabilizing structure wheel 7 and the inner stabilizing structure wheel 8 are respectively abutted to the outer ring side wall 12 and the inner ring side wall 13 of the slide rail 11.

In this embodiment, the outer stabilizing structure wheel 7 and the inner stabilizing structure wheel 8 are respectively abutted against the outer ring side wall 12 and the inner ring side wall 13 of the slide rail 11, the outer ring side wall 12 applies an acting force to the outer stabilizing structure wheel 7, and the inner ring side wall 13 applies an acting force to the inner stabilizing structure wheel 8, and the acting forces are opposite to each other, so that the moving base is laterally and stably limited at a preset position. Meanwhile, the outer stable structure wheel 7 and the inner stable structure wheel 8 can reduce the friction force between the movable base and the sliding rail 11, and reduce the friction loss.

, the embodiment of the present invention further provides kinds of 3D printers, where the 3D printer includes the selective laser melting device of the present invention, and the operation principle of the selective laser melting device is the same as above, and is not described herein again.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

The selective laser melting device of kinds includes one fixed part, one movable part and one moving mechanism;

the movable part is connected with the fixed part in a sliding way; the moving mechanism is connected with the movable part and used for driving the movable part to move along the circumferential direction relative to the fixed part; the moving mechanism is used for being electrically connected with a control system of the 3D printer; the movable part is used for installing a laser coupling and excitation mechanism of the 3D printer; the fixing part is used for being fixedly connected with a box body of the 3D printer;

the movable part comprises a moving part and a mounting part;

the mounting part is fixedly connected with the moving part; the mounting piece is used for mounting a laser coupling and excitation mechanism of the 3D printer;

the moving part is connected with the fixed part in a sliding way; the moving mechanism is connected with the moving part and used for driving the moving part to do circular motion relative to the fixed part; or

The movable part comprises a moving part, a mounting part and a rotating mechanism;

the mounting part is rotatably connected with the moving part; the rotating mechanism is connected with the mounting part and is used for driving the mounting part to rotate relative to the moving part; the rotating mechanism is used for being electrically connected with a control system of the 3D printer; the mounting piece is used for mounting a laser coupling and excitation mechanism of the 3D printer;

the moving part is connected with the fixed part in a sliding way; the moving mechanism is connected with the moving part and used for driving the moving part to do circular motion relative to the fixed part;

the fixed part is a circular sliding rail; the moving member comprises a moving base; the movable base is connected with the slide rail in a sliding manner;

a transverse limiting structure is arranged on the movable base; the transverse limiting structure is used for preventing the moving base from moving along the width direction of the sliding rail;

the transverse limiting structure comprises an outer stable structure wheel and an inner stable structure wheel which are rotatably connected with the movable base;

the outer stabilizing structure wheel and the inner stabilizing structure wheel are horizontally arranged, the outer stabilizing structure wheel is located at the end, close to the outer ring of the sliding rail, of the moving base, the inner stabilizing structure wheel is located at the end, close to the inner ring of the sliding rail, of the moving base, and the outer stabilizing structure wheel and the inner stabilizing structure wheel are respectively abutted to the outer ring side wall and the inner ring side wall of the sliding rail.
2. The selective laser melting apparatus of claim 1 wherein the slide track comprises a plurality of circular arc shaped sub-tracks; the sub-rails are connected in sequence to form a circular ring; the mobile base comprises a plurality of sub-bases; the moving mechanism comprises a plurality of moving structures; the mount comprises a plurality of sub-mounts;

the multiple sub-bases are arranged corresponding to the multiple sub-rails , each sub-base is connected with sub-rails in a sliding mode, the multiple sub-mounting bases are fixedly connected with the multiple sub-bases correspondingly, and each sub-mounting base is used for mounting a laser coupling and excitation mechanism of a 3D printer;

a plurality of the moving structures are arranged corresponding to the plurality of the sub-bases , and each of the moving structures is connected with of the sub-bases and is used for driving the sub-bases to slide along the extending direction of the sub-rail.
3. The selective laser melting apparatus of claim 1 wherein the moving member comprises an inside pulley and an outside pulley;

the inner side pulley is rotatably connected with the end, close to the inner ring of the slide rail, of the moving base, the outer side pulley is rotatably connected with the end, close to the outer ring of the slide rail, of the moving base, and the inner side pulley and the outer side pulley are vertically arranged and are abutted to the slide rail.
4. The selective laser melting apparatus of claim 3 wherein the diameter of the outside pulley is greater than the diameter of the inside pulley; the outer side sliding grooves and the inner side sliding grooves which are all annular are sequentially arranged on the sliding rail at intervals along the direction from the outer ring to the inner ring;

the outer side pulley is arranged in the outer side sliding groove; the inboard pulley sets up in the inboard spout, the degree of depth of inboard spout is less than the degree of depth of outside spout, inboard spout with the degree of depth difference of outside spout with outside pulley radius with the difference of inboard pulley radius is the same.
A3D printer of the kind , including a selective laser melting device of any of claims 1-4 to .