RU2797667C2 - Method for layer-by-layer production of product and device for its production - Google Patents

Abstract

FIELD: laser processing of materials.

SUBSTANCE: invention can be used in the layer-by-layer manufacturing of bulk products. The powder is fed in layers onto the working surface of the adjustable build platform and the layer is levelled. Layer sections are fused by identical sections on transverse sections of a three-dimensional computer model of the protective shell and the product previously formed by means of a given program. The protective shell is formed on the outer boundary, which coincides in plan with the boundary of the build platform. The unmelted material is removed into the container, the vacated space is filled with a powder made of an easily alloyed material, as compared with the material of the product, with its subsequent levelling and fusion. The device comprises a laser-optical device, a build chamber with a system for maintaining a working medium in the chamber, a build platform with a stand and a drive for its vertical movement, a basket for their placement, powder feed and powder layer levelling devices, a device for removing unmelted powder, a hopper for collecting excess powder, a screen fastened to the upper inner part of the basket, the lateral inner surface of which is made equidistant to the lateral surface of the build platform.

EFFECT: reduced powder consumption and accuracy of product geometry during its manufacture.

9 cl, 4 dwg

Description

The invention relates to the field of laser processing of materials and can be used in the layer-by-layer manufacture of bulk products, mostly of complex shape, from expensive powder materials, such as nickel heat-resistant alloys, cobalt-based alloys, and precious metals.

A method is known for layer-by-layer manufacturing of a product, which includes layer-by-layer supply of powder to the working surface of an adjustable construction platform, leveling the powder layer and fusing sections of the layer identical to sections on transverse sections of a protective shell and product pre-formed by a given program three-dimensional computer model [1].

The implementation of the protective shell allows you to get products with a more accurate geometry.

However, when applying the known technical solution, it is necessary to use a large amount of material (the shell is made on an unfused material), which leads to an increase in the amount of powder used. This increases the cost of manufacturing the product, especially in the manufacture of products from expensive powders, such as cobalt, nickel, precious metals.

It is also known a device that includes a laser-optical device, a build chamber with a system for maintaining a working environment in the chamber connected to a stand construction platform with a drive for its vertical movement, a basket for placing the build platform and its drive, a device for supplying powder and leveling the powder layer on the build platform , a device for removing unsintered powder from each layer, a hopper for collecting excess powder that is formed during the formation of a layer [2].

However, when using this device, there is also an increased consumption of expensive powder.

The result to which this technical solution is directed is to reduce the consumption of powder while ensuring the accuracy of the geometry of the product during its manufacture.

This result is achieved due to the fact that in the method of layer-by-layer manufacturing of a product, which includes layer-by-layer supply of powder to the working surface of an adjustable construction platform, leveling the powder layer and fusing sections of the layer identical to sections on the cross sections of a three-dimensional computer model pre-formed by a given program, and creating a protective shells and products, the protective shell is made on the outer boundary, coinciding in plan with the boundary of the construction platform, the unfused material is removed into the container corresponding to the powder, after the removal of the unfused material, a buffer zone is created in the freed space of the layer, filling the space with powder from an easily alloyed material , in comparison with the material of the product, with its subsequent leveling and fusion. Excess material resulting from the leveling of the buffer zone is placed in an appropriate container.

Aluminum or copper is used as a fusible material. The width of the protective shell is 1÷1.5 mm.

This result is also achieved due to the fact that in a device for layer-by-layer manufacturing of a product, including a laser-optical device, a build chamber with a system for maintaining a working environment in the chamber connected to a stand, a build platform with a drive for its vertical movement, a basket for placing the build platform and its drive, powder feeding device and leveling the powder layer on the build platform, device for removing unsintered powder from each layer, hopper for collecting excess powder that is formed during the formation of the layer. The device is equipped with a screen fastened to the upper inner part of the basket, the side surface of which is made equidistant to the side surface of the construction platform. The screen is provided with a seal located on its side surface. The construction platform and the screen are respectively removable and replaceable. The device is equipped with a partition fastened to a rack with a seal interacting with the inner wall of the basket, wherein the lower surface of the partition, the inner wall and the bottom of the basket form an intermediate chamber connected to the system for maintaining the working medium in the chamber, and the upper surface of the partition and the inner wall of the basket form a collection bin excess powder.

An example of the implementation of the claimed technical solutions is illustrated by drawings, where in Fig. 1 shows the claimed device, Fig. 2, 3, 4 - respectively, types A, B. C.

The device is equipped with a laser-optical device 1, a building chamber 2 with a system 3 for maintaining the working medium in the chamber, connected to the stand 4, a building platform 5 with a drive 6 for its vertical movement, devices 7, 8, respectively, for supplying the powder and a device 9 for leveling the powder layer on the platform 5 building (squeegee), a vacuum device 10 for removing unfused powder from each layer, a hopper 11 for collecting excess powder that is formed during the formation of a layer, a basket 12 for placing the building platform and its drive, fastened to the upper inner part 13 of the basket 12 by a screen 14, the lateral inner surface 15 of which is made equidistant to the lateral surface of the construction platform. The screen 14 is provided with a seal 16 located on its side surface.

The build platform and the screen are made respectively removable and replaceable, for which a detachable connection 17 of the build platform and rack 4 is provided.

The device is equipped with a partition 18 fastened to the rack 4, provided with a seal 20 interacting with the inner wall 19 of the basket. 24 partitions 18 and the inner wall of the basket 19 - hopper 11 to collect excess powder. The intermediate chamber is designed to prevent the release of the smallest powder particles into the environment.

The method of layer-by-layer manufacturing of a product includes layer-by-layer supply of powder to the working surface 25 of an adjustable construction platform, leveling the powder layer and fusing sections of the layer identical to sections on the cross sections of a protective shell 26 and product 27 previously formed by a given program of a three-dimensional computer model, and removing unfused material from layer in the corresponding powder container (not shown in the drawing).

The protective shell 26 is performed on the outer boundary, which coincides in plan with the boundary of the construction platform. After removing the unfused material, a buffer zone 28 is created in the vacated space of the layer, filling the space with powder from an easily fused, compared to the product powder material, material, followed by its leveling and fusion. Excess material resulting from the leveling of the buffer zone is placed in an appropriate container. As an easily alloyed material, for example, aluminum or copper can be used. The width of the protective shell is 1÷1.5 mm.

The production of the product is as follows.

Select a removable build platform and screen according to the product size. The first layer is formed from the material of the buffer zone and leveled by the device 9 (squeegee). Excess material falling on the screen is removed by vacuum device 10 into an appropriate container. A small amount of material that enters the intermediate chamber is removed by the system 3 for maintaining the working medium in the chamber. Seal 16 between screen and build platform minimizes the amount of material that enters the hopper.

Then the buffer layer is fused.

The next layer is formed from the material of the manufactured product. Excess material falling on the screen is removed with a 10 V vacuum device, a container corresponding to this material. After the formation of the layer, the shell is fused and the corresponding section of the manufactured product is produced. The unfused powder is then removed and placed in an appropriate container.

The material of the buffer zone is placed in the vacated section of the layer and, after its leveling and fusion, proceed to the formation of the next layer.

In this case, all layers are formed on the prepared surfaces of the buffer zone and on sections of the manufactured product, in contrast to the method according to the technical solution [1], in which the next layer, depending on the configuration of the manufactured product, can be placed on the unfused powder, and taking into account that the thickness of each layer, depending on the configuration of the product, may vary, there is a high probability of partial fusion of the previous layer with the next one, which affects the accuracy of the geometry of the manufactured product.

When the build platform is lowered to form the next layer, the seal 16 slides over the containment 26 and minimizes the flow of powder into the hopper 11 when leveling the layer.

After the product is manufactured, the material of the buffer zone is removed, for example, by heating the product, and the shell material is sent for further processing.

Since during the formation of the layer the powder is leveled over the entire surface, optimizing the size of the build platform depending on the size of the product leads to a decrease in the amount of powder involved in the manufacture of the product.

Thus, this technical solution will allow:

• reduce the amount of powder used from which the product is made;

• improve the accuracy of the geometric dimensions of the product.

Information sources

1. Patent US 9844913, MKI-B22F 3/105, 2017.

2. Patent RU No. 2614291, MKI - B22F 3/105, 2014.

Claims (9)

1. A method for layer-by-layer manufacturing of an article from a powder, which includes layer-by-layer supply of powder to the working surface of an adjustable construction platform, leveling the powder layer, fusing sections of the layer identical to sections on cross sections of a protective shell and product pre-formed by a given program three-dimensional computer model, characterized in that a protective shell is formed on the outer boundary, coinciding in plan with the boundary of the construction platform, and the unfused material is removed into a container corresponding to the powder, after removal of the unfused material, a buffer zone is created in the freed space of the layer, while filling the space with powder from an easily alloyed material, compared with the material of the product, followed by its leveling and fusion. 2. The method according to claim 1, characterized in that the excess material obtained by leveling the buffer zone is placed in a corresponding container. 3. The method according to p. 1, characterized in that aluminum is used as an easily alloyed material. 4. The method according to p. 1, characterized in that copper is used as an easily alloyed material. 5. The method according to p. 1, characterized in that the protective shell is made 1-1.5 mm wide. 6. A device for layer-by-layer manufacturing of a product from a powder by the method according to claim 1, containing a laser-optical device, a construction chamber with a system for maintaining a working medium in the chamber, a construction platform with a stand connected to the drive for its vertical movement, a basket for placing the construction platform and its a drive, a device for supplying powder and leveling a layer of powder on a build platform, a device for removing unsintered powder from each layer, a hopper for collecting excess powder that is formed during the formation of a layer, while it is equipped with a screen fastened to the upper inner part of the basket, the lateral inner surface of which made equidistant side surface of the construction platform. 7. Device according to claim. 6, characterized in that it is provided with a seal located on the side surface of the screen between the screen and the build platform. 8. The device according to claim 6 or 7, characterized in that the construction platform and the screen are respectively removable and replaceable. 9. The device according to any one of paragraphs. 6-8, characterized in that it is provided with a baffle fastened to the rack with a seal interacting with the inner wall of the basket, wherein the lower surface of the baffle, the inner wall and the bottom of the basket form an intermediate chamber connected to the system for maintaining the working medium in the chamber, and the upper surface of the baffle and the inner wall of the basket form a hopper to collect excess powder.

Images