CN104325140B - Precinct laser fusion increases the flexible spreading methods of material manufacture metal dust and device - Google Patents

Abstract

The invention discloses a method and a device for flexible spreading of metal powder for selective laser melting additive manufacturing. When the powder-spreading teeth whose lower ends are flush with each other move on the powder-spreading plane, the metal powder is laid flat by the powder-spreading teeth. When the powder-spreading process encounters a hard protrusion, the position of the powder-spreading teeth is automatically and reasonably realized by gravity and magnetic force. and smooth adjustment. The metal powder flexible spreading device for selective laser melting additive manufacturing that realizes the method includes a fixed box and a magnetic suction plate arranged in the fixed box, a powder spreading tooth unit and a reset pressing block, and the magnetic suction plate is fixed in the fixed box. The powder tooth unit is adsorbed on the magnetic suction plate by magnetic force, and the powder tooth unit carries the reset pressing block. The principle of the method of the present invention is ingenious, convenient and easy to implement; the metal powder flexible spreading device manufactured by selective laser melting additive has the advantages of simple structure, long service life, less traces of powder spreading, and accurate obstacle avoidance.

Description

Method and device for flexible spreading of metal powder for selective laser melting additive manufacturing

technical field

The invention relates to the technical field of additive manufacturing, in particular to a method and device for flexible spreading of metal powder for selective laser melting additive manufacturing.

Background technique

With the development of science and technology, there are various methods for rapid prototyping of metal parts, among which selective laser melting is a commonly used rapid prototyping method. The forming process of selective laser melting is as follows: the powder spreading device spreads a layer of metal powder on the forming cylinder, the laser beam is controlled by the computer, and according to the shape information of the formed part interface, the powder is selectively scanned to make the powder in the scanning area stick Knot or melt to obtain the single-layer shape of the formed part; then the forming cylinder descends a layer thick distance, the powder spreading device re-spreads powder, and continues to form the next layer; so layer by layer, finally obtain a metal part with a specific geometric shape .

Please refer to Figure 1, which is a schematic diagram of traditional powder spreading. In the traditional additive manufacturing process, the powder spreading device is a round rod-shaped powder spreading roller or a rigid powder spreading scraper Q. During the new powder spreading process, it is very easy for the powder spreading mechanism to collide with the hard protrusion T, resulting in the formation of parts Damaged, even because the powder spreading mechanism is stuck, the molding process is forced to be interrupted. Therefore, metal parts additive manufacturing equipment with this type of powder spreading mechanism has very strict requirements on the forming process, resulting in high equipment operating costs.

In order to prevent this phenomenon, some equipment manufacturers have adopted flexible powder spreading technology in the selective laser melting process. The scrapers used for powder spreading are usually elastic metal sheet materials, such as 0.2mm stainless steel sheets etc., the metal sheet material is made into a comb shape, and multiple comb-shaped elastic scrapers are superimposed on each other to form a flexible powder spreading scraper. During the powder spreading process, if there is a hard protrusion, the elastic scraper It will deform and bypass the hard protrusion, and then return to the original shape after bypassing the hard protrusion, and continue the powder spreading action. However, due to the repeated deformation of the tooth-shaped flexible powder spreading scraper during the working process, and the thermal action of the powder bed or the hard protrusions in contact with it during the powder spreading process, it is very easy to undergo plastic deformation, so it must be replaced every once in a while. Toothed flexible powder spreading scraper.

Contents of the invention

In order to overcome the shortcomings and deficiencies in the prior art, the present invention provides a method for flexible spreading of metal powder for selective laser melting additive manufacturing.

At the same time, the invention provides a metal powder flexible spreading device for selective laser melting additive manufacturing.

The present invention is achieved through the following technical solutions:

A method for flexible spreading of metal powder for selective laser melting and additive manufacturing, comprising the following steps: setting a metal powder flexible spreading device for selective laser melting and additive manufacturing on a powder spreading plane, and the powder spreading tooth units in the device are arranged in parallel with each other The lower ends of these powder-spreading teeth are flush with each other and are in contact with the metal powder. The metal powder flexible spreading device for selective laser melting additive manufacturing moves on the powder-spreading plane, and the metal powder is laid evenly by the powder-spreading teeth; When the powder spreading plane has hard protrusions, the powder spreading teeth corresponding to the hard protrusions are lifted up by the hard protrusions, and after passing through the hard protrusions, the lifted powder spreading teeth reset the gravity Reset under the action, and be adsorbed and positioned by magnetic force; the powder-spreading teeth that are not in contact with the hard protrusions are attracted and positioned at the original position by magnetic force without being affected by the movement of the lifted powder-spreading teeth.

Compared with the prior art, the metal powder flexible spreading method for selective laser melting and additive manufacturing of the present invention is ingenious in principle, convenient and easy to implement, and uses the gravity of the reset briquetting block and the magnetic force between the powder spreading teeth to realize the automatic, reasonable and accurate position of the powder spreading teeth. The smooth adjustment achieves the effect of flexible powder spreading, which provides a new option for the metal powder flexible spreading method of selective laser melting additive manufacturing.

A metal powder flexible spreading device for selective laser melting additive manufacturing, including a fixed box and a magnetic suction plate arranged in the fixed box, a powder spreading tooth unit and a reset pressing block, and the magnetic suction plate is fixed in the fixed box , the powder spreading tooth unit is adsorbed on the magnetic suction plate by magnetic force, and the powder spreading tooth unit carries the reset pressing block. Further, the powder spreading tooth unit includes a powder spreading tooth, and the powder spreading tooth includes a magnetically conductive part, and the magnetically conductive part of the powder spreading tooth is adsorbed on one side of the magnetic suction plate.

Further, the powder spreading tooth also includes a non-magnetic conductive part, and the non-magnetic conductive part is fixedly connected under the magnetic conductive part.

Further, the powder-spreading teeth of the powder-spreading tooth unit are arranged in parallel with each other, and the magnetically conductive parts of adjacent powder-spreading teeth have the same polarity under the magnetization of the magnetic suction plate.

Further, the upper end surface and the lower end surface of each powder spreading tooth of the powder spreading tooth unit are respectively flush.

Further, a through hole is opened on the bottom surface of the fixed box, and the lower end of the powder spreading tooth unit protrudes from the through hole.

Further, the upper part of the fixed box is open; a dustproof cover is also included, and the dustproof cover is placed on the upper part of the fixed box.

Compared with the prior art, the metal powder flexible spreading device for selective laser melting additive manufacturing of the present invention utilizes the gravity of the reset briquetting block and the magnetic force between the powder spreading teeth to realize automatic, reasonable and stable adjustment of the position of the powder spreading teeth, achieving flexible powder spreading It has the advantages of simple structure, long service life, less traces of powder coating, and accurate obstacle avoidance.

For better understanding and implementation, the present invention will be described in detail below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a schematic diagram of traditional powder spreading.

Fig. 2 is a schematic diagram of the selective laser melting additive manufacturing of the first embodiment.

Fig. 3 is an A-A cross-sectional view of a metal powder flexible spreading device for selective laser melting additive manufacturing.

Fig. 4 is a B-B sectional view of a metal powder flexible spreading device for selective laser melting additive manufacturing.

Fig. 5 is a partial cross-sectional view of the powder spreading tooth when it is pushed up by a hard protrusion.

Fig. 6 is a schematic diagram of the installation of the slider connection seat of the metal powder flexible spreading device for selective laser melting additive manufacturing.

Fig. 7 is a schematic diagram of the selective laser melting additive manufacturing of the second embodiment.

Detailed ways

Embodiment one

Please refer to FIG. 2 , which is a schematic diagram of the selective laser melting additive manufacturing of the first embodiment. The selective laser melting additive manufacturing device of this embodiment includes a forming cylinder piston X and a material cylinder piston Y arranged side by side, and a metal powder for selective laser melting additive manufacturing located above the forming cylinder piston X and material cylinder piston Y is flexibly spread Device P. The metal powder is laid on the upper surface of the forming cylinder piston X and the material cylinder piston Y, and is paved by the metal powder flexible spreading device P for the selective laser melting additive manufacturing.

Please refer to Figure 3 and Figure 4 at the same time, Figure 3 is the A-A sectional view of the metal powder flexible spreading device for selective laser melting additive manufacturing, and Figure 4 is the B-B sectional view of the metal powder flexible spreading device for selective laser melting additive manufacturing.

The metal powder flexible spreading device P for selective laser melting and additive manufacturing of the present invention includes a reset pressing block 1, a powder spreading tooth unit 2, a magnetic suction plate 3, a fixing box 4 and a dustproof cover 5, a reset pressing block 1, a powder spreading The tooth unit 2 and the magnetic suction plate 3 are arranged in the fixed box 4, the magnetic suction plate 3 is fixed on the inner bottom surface of the fixed box 4, the powder spreading tooth unit 2 is adsorbed and positioned on the magnetic suction plate 3 by magnetic force, and the powder spreading tooth unit 2 Bearing the reset pressing block 1, the dust cover 5 is placed above the fixed box 4.

Specifically, the powdering tooth unit 2 is composed of more than 50 pieces of powdering teeth 21 stacked in parallel, the powdering teeth 21 are arranged in parallel with each other, and the thickness of each piece of powdering teeth 21 is 0.5mm-1mm. The upper end surface and the lower end surface of each powder spreading tooth 21 are respectively flush. The powder spreading tooth 21 includes a magnetically permeable part 211 and a non-magnetically permeable part 212. In this embodiment, the magnetically permeable part 211 is preferably arranged in a "U" shape, and the reset pressing block 1 is nested in the "U" shaped structure. In this way, The powder spreading tooth unit 2 more stably carries the reset pressing block 1; the magnetically conductive part 211 is adsorbed on one side of the magnetic suction plate 3, and the non-magnetically conductive part 212 of the powder spreading tooth 21 is fixedly connected under the magnetically conductive part 211. In this embodiment The magnetically permeable part 211 and the nonmagnetically permeable part 212 are preferably connected by welding. The magnetically conductive part 211 is made of stainless steel magnetically conductive material, and the nonmagnetically conductive part 212 is made of nonmagnetically conductive metal materials, such as copper alloy, titanium alloy, aluminum alloy, etc. In this embodiment, the nonmagnetically conductive part 212 is preferably made of copper alloy. A through hole is provided on the bottom surface of the fixed box 4, and the lower end of the powder spreading tooth unit 2 protrudes from the through hole.

Further, the magnetic suction plate 3 is made of materials with residual magnetism, such as rare earth NdFeB permanent magnet materials, magnetized iron blocks, etc. In this embodiment, the magnetic suction plate 3 is preferably made of rare earth NdFeB permanent magnet materials . The magnetism of the magnetic suction plate 3 can magnetize the magnetically conductive part 211 of the powder spreading teeth 21, so that the magnetic suction plate 3 can firmly hold each powder spreading tooth 21; The polarities of 211 are the same and there is repulsive force, so the friction force between adjacent powder spreading teeth 21 can be neglected. The position where the magnetic suction plate 3 is placed in the fixed box 4 should be such that the magnetized surface is arranged along the up and down direction, and its size needs to be obtained through calculation. The calculation principle is to ensure that the magnetic induction intensity on the surface of the magnetic suction plate 3 can relatively firmly absorb the powder-spreading teeth 21, and make the influence of the magnetic suction plate 3 on surrounding objects beyond 3mm as small as possible.

Further, the fixing box 4 is made of non-magnetic metal material, such as aluminum alloy, copper alloy, etc., and aluminum alloy is preferably used in this embodiment. The wall thickness of the fixed box 4 should ensure that the outer wall of the fixed box 4 will not be absorbed by the magnetically conductive metal powder due to the effect of the magnetic suction plate 3 .

Further, the gravitational action of the reset briquetting block 1 can reset the raised tooth piece after bypassing the hard protrusion during the powder spreading process; the dust cover 5 is used to prevent dust from entering the fixed box 4 . In order to prevent the magnetic suction plate 3 from generating magnetic force on the reset briquetting block 1 and the dust cover 5, the reset briquetting block 1 and the dust cover 5 also adopt non-magnetic metal materials, such as copper alloy, aluminum alloy, etc. The block 1 is preferably made of copper alloy, and the dustproof cover 5 is preferably made of aluminum alloy.

Please refer to Fig. 5, which is a partial cross-sectional view of the powder spreading tooth when it is pushed up by the hard protrusion. During the powder spreading process, if there is no hard protrusion T beyond the powder spreading plane, the powder spreading teeth 21 of the powder spreading tooth unit 2 are arranged neatly, and the lower part is a flat plane, so that the powder is laid evenly. If there is a hard protrusion T beyond the powder spreading plane, the powder spreading tooth 21 at the corresponding position of the hard protrusion T will be lifted up under the force of the hard protrusion T, and the reset pressing block 1 will also be lifted up at the same time. When the powder spreading device continues to move forward and leaves the hard protrusion T, the force of the hard protrusion T on the powder spreading tooth 21 disappears, and the reset pressing block 1 is reset under the action of gravity, and the powder spreading tooth 21 is also under the action of gravity of the reset pressing block 1 Lower back to the original position. Adjacent powder-spreading teeth 21 that do not touch the hard protrusion T, on the one hand, are subjected to the suction force of the magnetic suction plate 3, so that they cannot produce vertical displacement; The same but there is mutual repulsion, and the friction between the powdering teeth 21 is very small, so even if the powdering teeth 21 that touch the hard protrusion T are lifted up, the adjacent powdering teeth 21 will still be attracted to the magnetic suction plate 3, the smoothness of powder spreading when the adjacent powder spreading teeth 21 do not meet the hard protrusion T is guaranteed.

Fig. 6 is a schematic diagram of the installation of the slider connection seat of the metal powder flexible spreading device for selective laser melting additive manufacturing. Install the slider connecting seat 6 on both sides of the metal powder flexible spreading device P for selective laser melting additive manufacturing, and fix the slider connecting seat 6 to the guide rail slider. The metal powder flexible spreading device P for selective laser melting additive manufacturing uses a slider to slide on the guide rail to spread powder.

The working process of this selective laser melting additive manufacturing device is described in detail as follows:

Initially, the metal powder flexible spreading device P for selective laser melting additive manufacturing is located on the side of the material cylinder piston Y, and before the metal powder flexible spreading device P for selective laser melting additive manufacturing moves, the material cylinder piston Y first rises by 1 The distance of the powder layer, the piston X of the forming cylinder is correspondingly lowered by the distance of 1 powder layer; then the metal powder flexible spreading device P for selective laser melting additive manufacturing is used for powder laying. During the powder spreading process, if there is no hard protrusion T beyond the powder spreading plane, the powder spreading teeth 21 of the powder spreading tooth unit 2 are neatly arranged, and the lower part is a flat plane, so that the powder is laid evenly. When encountering a hard protrusion T exceeding the powder-spreading plane, the powder-spreading tooth 21 at the corresponding position of the hard protrusion T will be lifted up under the force of the hard protrusion T, and the reset pressing block 1 will also be lifted up at the same time. When the powder spreading device continues to move forward and leaves the hard protrusion T, the force of the hard protrusion T on the powder spreading tooth 21 disappears, and the reset pressing block 1 is reset under the action of gravity, and the powder spreading tooth 21 is also under the action of gravity of the reset pressing block 1 Return to the original position and be held by the magnetic suction plate 3. Adjacent powder-spreading teeth 21 that do not touch the hard protrusion T, on the one hand, are subjected to the suction force of the magnetic suction plate 3, so that they cannot produce vertical displacement; The same but there is mutual repulsion, and the friction between the powdering teeth 21 is very small, so even if the powdering teeth 21 that touch the hard protrusion T are lifted up, the adjacent powdering teeth 21 will still be attracted to the magnetic suction plate 3, the smoothness of powder spreading when the adjacent powder spreading teeth 21 do not meet the hard protrusion T is guaranteed. As the metal powder flexible spreading device P for selective laser melting additive manufacturing moves to one side of the forming cylinder piston X, the powder spreading process ends.

Embodiment two

Please refer to FIG. 7 , which is a schematic diagram of the selective laser melting additive manufacturing of the second embodiment. A metal powder flexible spreading device P for selective laser melting additive manufacturing is installed on both sides of the powder hopper D to form a powder hopper-type flexible powder spreading device E. The structure of the metal powder flexible spreading device P for selective laser melting additive manufacturing in this embodiment is the same as that in Embodiment 1.

The powder coating process of the selective laser melting additive manufacturing device of the present embodiment is as follows:

Initially, the powder hopper-type flexible powder spreading device E is located on the side of the forming cylinder piston X. Before the powder hopper-type flexible powder spreading device E moves, the forming cylinder piston X descends the distance of 1 powder layer, and then the powder hopper-type flexible powder spreading device E The powder unit E performs powder laying. During the powder spreading process, if there is no hard protrusion T beyond the powder spreading plane, the powder spreading teeth 21 of the powder spreading tooth unit 2 are neatly arranged, and the lower part is a flat plane, so that the powder is laid evenly. When encountering a hard protrusion T exceeding the powder spreading plane, the powder spreading tooth 21 at the corresponding position of the hard protrusion T will be lifted up under the force of the hard protrusion T, and the reset pressing block 1 will also be lifted up at the same time. When the powder spreading device continues to move forward and leaves the hard protrusion T, the force of the hard protrusion T on the powder spreading tooth 21 disappears, and the reset pressing block 1 is reset under the action of gravity, and the powder spreading tooth 21 is also under the action of gravity of the reset pressing block 1 Return to the original position and be held by the magnetic suction plate 3. Adjacent powder-spreading teeth 21 that do not touch the hard protrusion T, on the one hand, are subjected to the suction force of the magnetic suction plate 3, so that they cannot produce vertical displacement; The same but there is mutual repulsion, and the friction between the powder spreading teeth 21 is very small, so even if the powder spreading teeth 21 that touch the hard protrusion T are lifted up, the adjacent powder spreading teeth 21 will still be adsorbed on the magnetic suction plate 3, the smoothness of powder spreading when the adjacent powder spreading teeth 21 do not meet the hard protrusion T is guaranteed. As the powder hopper type flexible powder spreading device E moves to the other side of the forming cylinder piston X, the powder spreading process ends.

Compared with the prior art, the metal powder flexible spreading method for selective laser melting additive manufacturing of the present invention is ingenious in principle, convenient and easy to implement, and provides a new option for the flexible spreading of metal powder in selective laser melting additive manufacturing technology. The metal powder flexible spreading device for selective laser melting and additive manufacturing of the present invention is provided with reset pressing blocks and powder spreading teeth with magnetically conductive parts, and uses the gravity of the reset pressing blocks and the magnetic force between the powder spreading teeth to realize the automatic and automatic position of the powder spreading teeth. Reasonable and stable adjustment achieves the effect of flexible powder spreading. It has the advantages of simple structure, long service life, less traces of powder spreading, and accurate obstacle avoidance.

The present invention is not limited to the above-mentioned embodiments, if the various changes or deformations of the present invention do not depart from the spirit and scope of the present invention, if these changes and deformations belong to the claims of the present invention and the equivalent technical scope, then the present invention is also It is intended that such modifications and variations are included.

Claims (8)

1. A metal powder flexible spreading method for selective laser melting and additive manufacturing, comprising the following steps: the metal powder flexible spreading device for selective laser melting and additive manufacturing is arranged on the powder spreading plane, and the powder spreading tooth unit in the device consists of multiple The powder coating teeth are arranged in parallel. The lower ends of the powder coating teeth are flush with each other and are in contact with the metal powder. The metal powder flexible spreading device for selective laser melting additive manufacturing moves on the powder coating plane, and the metal powder is covered by the powder coating teeth. Flat laying; if hard bumps are encountered during the powder spreading process, by using gravity and magnetic force, each powder spreading tooth can automatically, reasonably and smoothly adjust the corresponding position, ensuring the stability of the powder spreading process and the smooth spreading of the powder; When the powder spreading plane has hard protrusions, the powder spreading teeth corresponding to the hard protrusions are lifted up by the hard protrusions, and after passing through the hard protrusions, the lifted powder spreading teeth reset the gravity Reset under the action, and be adsorbed and positioned by magnetic force; the powder-spreading teeth that are not in contact with the hard protrusions are attracted and positioned at the original position by magnetic force without being affected by the movement of the lifted powder-spreading teeth. 2. A metal powder flexible spreading device for selective laser melting and additive manufacturing. In the fixed box, the powder spreading tooth unit is magnetically attracted to the magnetic suction plate, and the powder spreading tooth unit carries the reset pressure block. 3. The metal powder flexible spreading device for selective laser melting additive manufacturing according to claim 2, characterized in that: the powder spreading tooth unit includes a powder spreading tooth, the powder spreading tooth includes a magnetically conductive part, and the powder spreading tooth unit The magnetically conductive part of the powder tooth is adsorbed on one side of the magnetic suction plate. 4. The metal powder flexible spreading device for selective laser melting additive manufacturing according to claim 3, characterized in that: the powder spreading tooth also includes a non-magnetic conductive part, and the non-magnetic conductive part is fixedly connected to the magnetic conductive part below. 5. The metal powder flexible spreading device for selective laser melting additive manufacturing according to any one of claims 3 or 4, characterized in that: the powder spreading teeth of the powder spreading tooth unit are arranged in parallel to each other, and the adjacent powder spreading teeth The magnetically conductive part has the same polarity under the magnetization of the magnetic suction plate. 6 . The metal powder flexible spreading device for selective laser melting additive manufacturing according to claim 5 , wherein the upper end surface and the lower end surface of each powder spreading tooth of the powder spreading tooth unit are flush with each other. 7 . 7 . The metal powder flexible spreading device for selective laser melting additive manufacturing according to claim 6 , wherein a through hole is opened on the bottom surface of the fixed box, and the lower end of the powder spreading tooth unit protrudes from the through hole. 8 . 8. The metal powder flexible spreading device for selective laser melting additive manufacturing according to claim 7, characterized in that: the upper part of the fixed box is open; and a dustproof cover is also included, and the dustproof cover is placed above the fixed box .