Device to manufacture items by layer-by-layer laser agglomeration of powders

FIELD: metallurgy.

SUBSTANCE: device to manufacture items by layer-by-layer laser agglomeration of powders contains tanks for powder and powder surpluses, located between them module for item forming including table with drive of its vertical movement, device for powder supply to the table from powder tank, and powder discharge to power surpluses tank, optical laser system for agglomeration of the powder nozzles installed above the table for air or inert gas supply on the powder layer, and gas intake installed under the table with possibility of connection with vacuum system. The table is made gas permeable and is equipped with installed on its top surface of the refractory gas permeable plate intended for powder layer arrangement on its surface and agglomeration.

EFFECT: improved quality of obtained items.

1 dwg

 

The invention relates to the field of powder metallurgy and can be used for manufacture of products, including complex shapes, made of fine metal, ceramic powders and mixtures thereof layer-by-layer laser synthesis, and may find application in various engineering industries.

Known powder laser sintering, comprising a housing with a work space, isolated from the surrounding atmosphere. The case comprises a laser device with the optical system having the possibility of lateral movement in two coordinates by means of the actuator, a technological platform for placement of sintered material, is movably mounted for movement in a vertical direction drive means, a hopper with means for feeding powder into the working space above the technology platform. The installation also comprises a device control and maintain the desired thickness of the powder layer comprising a vibrator, a sensor monitoring the level of the surface of the powder layer and the compensator surface level of the powder layer mounted between the sidewalls of the technological platform and the housing is movable in the vertical direction by the actuator. The space formed by side walls of the technological platform, �of the Cabinet and the end surface of the compensator surface level of the powder layer, communicates with the hopper. The optical system, technology platform, compensator surface level of the powder layer and the sensor monitoring the level of the surface of the powder layer are connected with the control unit. The unit is equipped with a feeder neutral gas into the working space of the housing and the sensor to control the content of the neutral gas in the working space of the housing associated with the control unit, and device for creating a vacuum in the working space of the housing and the sensor control the residual pressure in the working space of the housing associated with the control unit (see patent RU No. 2299787, CL B22F 3/105, 2007).

As a result of the analysis of the implementation of the known installation it should be noted that in the course of its work the massive vibration of the table will ask the fluctuations of the entire installation, which negatively affects the stability of its work. In addition, vibratory compaction is not possible to provide the same density of compacted layer throughout its thickness, which reduces the quality of the obtained layer-by-layer sintering products. In addition, the product quality is negatively affected by the presence of vapor produced by laser sintering of a layer.

A device for producing parts from a powder consisting of a skeleton, on which is placed a hopper for raw material (powder) and cared�, having the ability to move the drive means along the guide rails of the frame. The device also includes a work Desk, equipped with a vertical movement drive and bunker collect the excess powder off the table. The carriage is equipped with a knife, equipped with a mechanism for vertical movement, intended for feeding portions of the powder to the desktop, align it on the desktop and reset the excess powder in the hopper and roller designed for compaction aligned on the desktop layer of the powder.

In operation, the device from the hopper to the desktop exercise dosage the grant of a powder, which is the movement of the knife is spread on the desktop, dumping the excess into the collection hopper of excess powder, followed by a sealing layer with a roller, working in free rolling. Next, perform the synthesis of the layer with a laser by moving the beam along a predetermined path. At the end of the synthesis process of the layer is lowered desktop on the value of the thickness of the next layer of powder, then the process is repeated as described above, forming the next layer of the product and so until then, until the formation necessary for obtaining the product of the number of layers (see patent RU No. 2423203, CL B22F 3/105, 2011 - the closest analogue).

As a result of analysis of the known solutions it is necessary to note�'it, in the process seal is aligned with the blade of a layer of powder it can be offset, and the violation of the uniform distribution of the layer on the table and his integrity. In addition, in the process of synthesis layer for the laser to high temperatures in the zone of formation of parts may change the structure of powder or melt, which reduces the quality of formed products. It should be noted that the presence in the zone of formation of the products of a large number of vapors of the product also reduces the quality of the resulting product.

The technical result of the present invention is to improve the quality of the products obtained in the process of layer-by-layer selective synthesis by providing effective removal of heat and vapour sintered material of the sintered powder mass by passing the gas flow through the powder mass, as well as compaction of the powder mass of the layer due to the difference of pressure of the gaseous medium over a Desk and under it.

It is also essential that in the process of operation of the device is ensured by the effective removal of metal vapors released during melting of the powder, due to the flow of the gaseous medium directed to the surface of the sintered layer. This allows to provide optimal conditions of laser operation, which increases the quality of the products.

The specified technical result� is provided for those device for the production of layer-by-layer laser sintering of powders containing capacity to accommodate for the excess powder and placed between the module of formation of a product comprising a table with a drive of its vertical movement, means for supplying powder from the container for placing it on the table and dump in the tank of the excess powder and optical laser sintering powder, what is new is that it contains are installed on the table of jet nozzle on the powder layer of air or inert gas and mounted under the table with the possibility of connection with the vacuum system hassebroek, the table is made gas permeable and come mounted on its upper plane of the refractory gas-permeable plate that is designed to accommodate on its surface, and sintering a layer of powder.

The invention is illustrated by drawings, which shows a diagram of an apparatus for producing articles from powders.

Apparatus for producing articles from powders comprises a container 1 for the raw material (powder or mixture of powders), the bottom 2 which has a vertical movement drive means (not shown), the container 3 for discharge of surplus materials, the bottom 4 which has the possibility of vertical movement drive means (not shown). Between the vessels deployed module forming�ing products made in the form of the body 5, in which the possibility of vertical movement by the actuator 6 with table 7, made in the form of a frame or plate with through holes that allows you to skip through it a flow of gas, i.e. the table is gas permeable. On the upper surface of the table 7 fixed refractory gas-permeable plate 8 made of, e.g., quartz sand, reinforced binder based on water glass. This plate has a sufficient gas permeability and durability, and fire resistance that allows you to produce on its surface the layer-by-layer sintering of the powder.

Above the tanks 1, 3 and, on the module of formation of the products have an element 9 for suctioning powders from the container 1 and feed them to the plate 8 of table 7, as well as for levelling powders on the surface of the table and the removal of their surplus into the container 3. Element 9 can be performed in various known ways, for example in the form of a plate, knife, scraper, etc., installed on the carriage (not shown) mounted with the possibility of horizontal and vertical movement along the traverse (not shown) located above the containers and table.

Above the containers and a table, preferably on the same traverse, located on the carriage (not shown) of the optical system 10 of a laser capable of projecting a laser beam in the desired �point on the surface of the sintered powder layer 11, in the mass of which is formed the product by 12.

The device is equipped with nozzles 13 that are designed to supply air or inert gas (nitrogen or argon) is placed on the plate 8, the powder layer 11. Nozzle connected with a supply system (not shown) of gas. Nozzles can be installed on stand-alone racks or on the traverse.

Under the table 7 is hassebroek 14 connected with a vacuum system (not shown) designed to improve the efficiency of the gas passing through the powder layer 11, the table 7 and plate 8. The most appropriate hassebroek be attached directly on the table at the bottom.

Drives bottom 2 and bottom 4 of the containers 1 and 3, the actuator 6 of table 7, the actuator element 9, the optical system 10 of the laser associated with the control system, through which the control of the process upon receipt of the product 12.

The device operates as follows.

As raw materials can be used a wide range of powders or their mixtures with an average particle size of 30-40 μm. The powder is loaded into the container 1, the bottom 2 of which is lowered in position. Table 7 is raised to its highest position, so that the gap between the plate 8 and the element 9 was not more than 10 μm. The table 7 by means of the actuator 6 is lowered by the amount of the thickness of the layer of powder is placed on the plate 8 and the element 9, taking a portion of powder from the container 2, distributes it �auromere on the plate 8, dumping the excess into the container 3. Include the flow of gas through the nozzles 13 and associated with hassaballah 14 vacuum system. The beam of a laser system 10, moving along a predetermined path, specal powder in the required areas, forming a layer of the product.

Further, the above-described process is repeated many times. The product formed by the accumulation of new layers of metal on the already sintered, forming a monolithic body parts 12 of a predetermined shape and size. The amount of gas in the process of formation of the product through the layer of powder, the plate 8 and table 7 provides cooling zone of the sintering, compaction of the powder layer, and removing the vapor of the material powder generated in the sintering process which enables the production of high quality products.

After the process, the product 12 is removed from the plate 8, and especiany powder remaining on the plate 8, are sent for regeneration.

A device for producing products layer-by-layer laser sintering of powders containing capacity to accommodate powder and the excess powder and placed between the module of formation of a product comprising a table with a drive of its vertical movement, means for supplying powder on the table from the tank to house it and reset the powder in the reservoir for the excess powder and optical laser sintering of a powder, characterized in that it contains installed over St�scrap the jet nozzle on the powder layer of air or inert gas and mounted under the table with the possibility of connection with the vacuum system hassebroek, the table is made gas permeable and come mounted on its upper plane of the refractory gas-permeable plate that is designed to accommodate on its surface, and sintering a layer of powder.



 

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