EP4355518A1 - Additive manufacturing device - Google Patents

Abstract

The present invention relates to a device (100) for additive manufacturing by powder bed fusion, the device comprising an enclosure (102) that comprises: in a lower portion of the enclosure, a manufacturing plate (112) and a powder spreading means (114) capable of travelling across the manufacturing plate in order to spread, on said plate, powder previously deposited on the manufacturing plate; and, in an upper portion of the enclosure, a window (108) facing the manufacturing plate and allowing the passage of laser beams (110), the device (100) comprising at least one effector arranged inside the enclosure and connected to at least two actuators (120) configured to move said effector between the upper portion of the enclosure and a target position on the manufacturing platform (112).

Description

DESCRIPTION

TITLE: Additive manufacturing device

Technical field of the invention

This document relates to an additive manufacturing device, in particular by fusion on a powder bed.

State of the prior art

Additive manufacturing devices allow the manufacture of parts by selective melting of powder, using a laser additive manufacturing process known as Laser Beam Melting. Such a method consists in manufacturing a part by melting successive layers of powder by means of a laser beam controlled by an information processing system in which the three-dimensional coordinates of the points of the successive layers to be produced have been recorded. In practice, a first layer of powder is deposited by a powder dispenser on the bottom of a tank formed by a plate movable in vertical translation, using a scraper. The layer then has a lower surface corresponding to the upper surface of the plate and an upper surface on which the laser beam is directed and moved. The energy provided by this beam causes local melting of the powder which, on solidifying, forms a first layer of the metal part.

After formation of this first layer, the plate is lowered by a distance corresponding to the thickness of one layer, then a second layer of powder is brought by the scraper onto the previous layer. In the same way as before, a second layer of the metal part is formed by melting using the laser beam or the electron beam. These operations are repeated until the part is completely manufactured. The powder dispenser is fixed in the enclosure and deposits a quantity of powder at the same place on the plate, generally in front of the scraper, at one of the edges of the manufacturing plate. The scraper pushes the amount of powder deposited on the entire plate and thus spreads it over the entire surface of the build plate. It is not possible, with current devices, to deposit powder locally on a predetermined area of the manufacturing plate because these devices spread the powder over the entire plate each time powder is deposited. In addition, these devices do not allow the use of several different materials in the same enclosure. Finally, the quantity of powder to be deposited to manufacture the parts is significant and requires numerous handling operations, since it is necessary to spread the powder over the entire plate, especially if few parts have to be produced.

There is a need to improve additive manufacturing devices. Summary of the invention

This document proposes a device for additive manufacturing by melting on a powder bed, the device comprising an enclosure comprising, in a lower part of the enclosure, a manufacturing plate and a means for spreading powder capable of traversing the manufacturing plate. to spread powder thereon previously deposited on the manufacturing plate and comprising in an upper part of the enclosure a window facing the manufacturing plate and allowing the passage of laser rays, the device comprising at least one effector arranged in the enclosure and connected to at least two actuators configured to move said effector between the upper part of the enclosure and a target position at the manufacturing platform.

The device makes it possible to reach a target position at the level of the plate and thus makes it possible to operate locally at the level of the target position.

At least one effector can be equipped with a powder dispenser. In particular, the powder dispenser can be removably mounted to said effector. This makes it possible to locally deposit powder at a target powder deposit position. This powder can be locally distributed at the level of a target zone by the spreading means.

At least one effector can be equipped with a powder extractor. For example, the powder extractor can be removably mounted to said effector. Thus, the cleaning of the enclosure is thus automated. The device also saves time when depowdering the enclosure because the powder aspirator can be brought locally to a place on the manufacturing plate containing powder.

The device may comprise a flexible pipe connecting the vacuum cleaner to an air outlet opening provided in one of the walls of the enclosure.

The powder dispenser or the powder aspirator can be snap-fitted or screwed into the effector. Such assembly can be automated or manual.

The enclosure may be parallelepipedal. The top may include a top wall of the enclosure which may be square or rectangular. The enclosure may be airtight when closed.

The top wall may be opaque to laser rays. The window can be arranged in the upper wall and can comprise a pane adapted for the passage of laser beams.

The device may include a laser configured to emit laser beams perpendicular to the build plate.

The window can have dimensions smaller than the dimensions of the build plate and the laser can be oriented to emit laser beams to reach the entire build plate. The manufacturing plate can extend along a first direction and a second direction perpendicular to each other.

The powder spreading means may be movable in the first direction.

Each effector can be actuated by dedicated actuators. Alternatively, the actuators can be configured to drive at least two effectors in parallel.

For each effector, the device can comprise four actuators arranged in the upper part of the enclosure and each connected by a cable to said effector.

The actuators can be linear motors configured to wind or unwind one of the cables.

The cables may extend in the first direction.

For each effector, an actuator can be arranged at a corner of the upper wall.

The upper part can be arranged at a non-zero distance from the lower part in the third direction. For example, the upper part can be arranged at a distance of about 40 cm from the lower part or about 1.5 times the width of the tabletop.

The lower part can be formed by an area around the build plate in the third direction, for example up to 2 cm above the build plate, in other words in the direction of the upper wall.

The build plate may be movable in a third direction perpendicular to the first direction and the second direction. For example, the third direction can be vertical. In particular, the build plate can be lowered in the third direction away from the top. For example, the build plate can be lowered by a height corresponding to one layer of the part being built. Such a thickness can be between 20 and 60 microns, in particular equal to 40 microns.

For each effector, the actuators can be configured to move said effector in the first direction and/or the second direction.

For each effector, the actuators can be configured to move said effector in the third direction.

The device may comprise at least two effectors each equipped with a powder dispenser. The powder dispensers can include different powders. This makes it possible to deposit on a certain layer of the part being manufactured or on certain zones of the manufacturing plate, several materials.

The device may comprise at least two effectors each equipped with a powder extractor. For example, a specific powder vacuum cleaner can be provided for each type of powder used to recover said powder, and a universal powder vacuum cleaner can be provided for recovering different types of waste in the enclosure. For example, each specific powder vacuum can be arranged where the specific powder is deposited while the universal powder vacuum cleaner can be arranged at transition points between two places where specific powder is deposited. This arrangement makes it possible to recycle the powder and saves material.

Alternatively, the powder dispensers can comprise the same type of powder. The device may comprise several effectors each equipped with a powder dispenser and/or several effectors each equipped with a powder aspirator.

The device may comprise a first effector equipped with a powder dispenser and a second effector equipped with a powder aspirator.

The powder spreading means can be a scraper or a roller. The scraper can be formed by an iron blade.

The device may comprise means for actuating the powder spreading means in the first direction to move the latter upstream of the target position in the direction of scanning of the manufacturing plate. For example, the powder spreading means can be brought to a distance between 1mm and 1cm upstream of the target position.

The powder can be deposited progressively in front of the powder spreading means, following its progress. The powder spreading means makes it possible to make the thickness of the layer of powder homogeneous.

The powder spreading means may have a dimension in the second direction equal to or greater than the dimension of the manufacturing plate in the second direction. The enclosure may include, in the upper part, one or more waiting zones for the effector. For example, the waiting area(s) may be an area of the upper wall outside the window.

The enclosure may comprise in the upper part, one or more tool change areas, in which a powder dispenser and/or a powder extractor can be removed/mounted from/into the effector. For example, the tool change area or areas may be areas of the top wall outside the window, for example at an edge of the top wall. A tool change area can be confused with a waiting area.

For example, a powder dispenser may comprise a buffer stock container comprising powder and communicating with a cylinder fitted with a cross opening into a powder dispensing opening. The cross makes it possible to dose the deposit of the powder. The powder dispensing opening may have dimensions between 2 and 10 mm, in particular around 4 mm so that the powder does not remain blocked in the cylinder. The amount of powder deposited can be adjusted according to the speed of advance of the dispenser and of the powder spreading means and the speed of rotation of the cross inside the dispenser. The quantity of powder to be deposited at the target position can be determined according to the volume of material of the layer to be manufactured. In addition, the buffer stock bin may have a rectangular shape with asymmetrical side slopes forming an angle of minus 30° with respect to the third direction or the vertical to allow the descent of the powder. The buffer stock bin can have a capacity of 2L.

The enclosure may include a means for reloading the powder dispenser into powder. Such means may be an opening connected to a powder storage container. The opening can be arranged in the waiting area or the tool change area. The powder storage bin can have a capacity of 50L.

When the effector is equipped with a powder dispenser, the actuators can be configured to route the dispenser at a height between 1 mm and 10 mm from the build plate opposite the target powder deposit position in the build plate. manufacturing.

The device may include means for calibrating the actuators to associate the reference of the actuators with a reference position of the effector(s). Such calibration means can comprise a stop sensor.

The powder may be a metallic powder.

The device can be configured to manufacture a part of a turbomachine.

This document also relates to a use of a manufacturing device as mentioned above, comprising the steps: mounting a powder dispenser to an effector of the device, moving the powder dispenser to the target position of the manufacturing platform, depositing a predetermined quantity of powder, and sweeping the build plate with the powder spreading means.

Multiple powder dispensers can be mounted in the enclosure so that each end effector is equipped with a powder dispenser.

Each powder dispenser may include a different powder and may be at a predetermined target position.

The use may further include the steps: exposing the build plate to a laser beam, and lowering the build plate after exposure by the laser beam.

Use may include the steps of replacing the powder dispenser with a vacuum, and vacuuming the vacuum around a target position on the build plate.

In particular, the replacement and suction steps can be performed before lowering the build plate.

Brief description of figures [Fig. 1] is a schematic representation of a first embodiment of an additive manufacturing device in a first operating configuration.

[Fig. 2] is a schematic representation of the device of FIG. 1 in a second operating configuration.

[Fig. 3] is a schematic representation of the device of FIG. 1 in a third operating configuration.

[Fig. 4] is a schematic representation of a second embodiment of an additive manufacturing device in a first operating configuration.

[Fig. 5] is a schematic representation of the device of FIG. 4 in a second operating configuration.

Detailed description of the invention

Referring to Figures 1 to 3, the additive manufacturing device 100 comprises a parallelepiped enclosure 102 comprising an upper wall 104 and a lower wall 106. The upper wall 104 comprises a window 108 provided with a window allowing the passage of laser rays 110 while the rest of the upper wall is opaque to laser rays. A build plate 112 is connected to bottom wall 106 and extends in the XY plane. The build plate 112 can move along the Z axis, particularly in the -Z direction.

The device 100 comprises a scraper 114 formed by an iron blade and arranged movable along the Y axis. The scraper 114 is arranged above the build plate 112 and can sweep the surface of the build plate 112 along the -Y direction. . The width of the scraper 114 along the X axis is equal to the width of the build plate 112 along the X axis. According to one embodiment, the scraper 114 can be replaced by a roller capable of sweeping the surface of the build plate. 112.

The device 100 further comprises an effector equipped with a powder dispenser 116 connected to motors 120 by four cables 117 and 118 extending along the Y axis. The cables 117 are arranged upstream of the dispenser in the -Y direction. displacement of the scraper 114 and the cables 118 are arranged downstream of the dispenser 116 in the -Y direction of displacement of the scraper 114. Each motor 120 is arranged at a corner of the upper wall 104. The winding of the cables 118 and the unwinding cables 117 move scraper 116 in the -Y direction, and vice versa.

The cables 117 and 118 can be metallic or nylon cables allowing the mass of the dispenser to be held.

In operation, the scraper 114 is brought upstream of a powder deposit target position in the -Y direction. For example, the scraper is arranged at a distance of approximately 5 mm upstream from the target powder deposit position. Dispenser 116 is then moved by motors 120 to the target powder deposit position. The dispenser 116 can be arranged at a distance of 1 mm from the manufacturing plate in the direction Z opposite the projection of the target deposit position in the XY plane.

The dispenser 116 comprises a buffer stock container filled with powder and communicating with a cylinder in which is arranged a dispensing cross. The cylinder leads to a powder dispensing opening, which can have a width or a diameter of between 2 and 10mm, in particular around 4mm. The buffer stock bin can have a capacity of 2L.

The dispenser 116 is actuated to deposit powder as it moves along the -Y direction in front of the scraper 114. The latter can move simultaneously with the movement of the dispenser 116 and makes it possible to spread the powder by forming a powder bed 122 with a homogeneous layer thickness.

The quantity of powder deposited by the dispenser 116 is regulated according to the speed of advance of the dispenser 16 and the scraper 114, and the speed of rotation of the cross inside the cylinder of the dispenser 116.

As shown in FIG. 3, once the powder bed has been formed, the dispenser 116 is moved to a waiting zone 124 at the level of the upper wall 102 set back from the window 108 so as not to obstruct the passage of the laser rays. 110. The scraper 114 is also moved to an initial position, for example at an edge of the build plate 112. The initial position of the scraper 114 may be outside the build plate 112 on the bottom wall 106 of the enclosure. 102.

The powder bed 122 is then exposed to laser rays 110 for a predetermined duration, which causes it to melt and form a layer of material after it has solidified.

At the end of this operation, the manufacturing plate 112 is lowered in the -Z direction by a distance equivalent to the thickness of the layer formed, for example approximately 40 microns. Powder can again be deposited on build plate 112 to form the next layer on top of the layer already formed.

The dispenser 116 can be removed from its support connecting it to the cables 117 and 118. A vacuum cleaner (not shown in FIGS. 1 to 3) can be mounted on the support in place of the dispenser 116. The vacuum cleaner can sweep the layer formed to depowder the enclosure before depositing a new layer of powder. The vacuum cleaner can be connected to a discharge bag outside the enclosure, by a flexible hose.

The dismantling of the dispenser 116 can be carried out at the level of the waiting zone 116. This change can be automated or manual. The enclosure 102 may include a powder intake opening, for example arranged at the level of the waiting area 116. This powder intake opening may be connected to a powder storage tank of greater capacity. than the dispenser buffer stock tank 116, for example with a capacity of 50L, and makes it possible to refill the dispenser buffer stock tank 116 when it is empty or at an insufficient level.

The device 100 may comprise means for actuating the dispenser 116 along the X axis. Such means may comprise motors mounted on the fixing support of the dispenser 116 and connected by cables, extending along the X axis, to dispenser 116.

Referring to Figures 4 and 5, the additive manufacturing device 200 comprises the same elements as the device 100. In addition, the device 200 comprises a first dispenser 1161 and a second dispenser 1162. Each of the dispensers 116 is connected by cables 118 and 117 to motors 120. Each dispenser 116 moves independently of the other dispenser 116. The tray of the first dispenser 1161 comprises a first powder and the tray of the second dispenser 1162 comprises a second powder separate from the first powder.

As shown in Figure 4, the first dispenser 1161 is moved to a first powder deposit target position and the second dispenser 1162 is moved to a second powder deposit target position. Once the first and second powders have been deposited, the scraper 114 is actuated to sweep the entire surface of the manufacturing plate 112 and thus forms a first powder bed 122i and a second powder bed 1222. A means for cleaning the scraper 114 can be provided between the first and second powder depositing target positions, to avoid mixing the first powder and the second powder. Exposing the build plate 112 allows two layers of different materials to be formed. The first powder and the second powder can be metallic powders.

The waiting area 124 can simultaneously accommodate the first dispenser 1161 and the second dispenser 1162. Alternatively, the waiting area 124 can accommodate only one of the first dispenser 1161 and the second dispenser 1162, the enclosure which may include another waiting area, arranged for example opposite the waiting area 124 with respect to the window 108, to accommodate the other of the first dispenser 1161 and the second dispenser 1162.

As shown in Figure 5, the second dispenser 1162 can be replaced by a vacuum cleaner 126 connected by a flexible pipe 130 to an opening 128 provided in a side wall 132 of the enclosure. Opening 128 can be connected to a powder collection bag. The vacuum cleaner 126 can sweep the whole of the enclosure 102 to depowder it or only an area around the second target position for depositing powder. The vacuum cleaner 126 can thus be used to recover any waste in the enclosure or only the remains of the second powder after exposure to laser beams. During the cleaning of the enclosure, the scraper 114 is arranged in the initial position.

Similarly, the first dispenser 1161 can be replaced by a vacuum cleaner which can be used to recover only the remains of the first powder.

Claims

1. Device (100,200) for additive manufacturing by melting on a powder bed, the device comprising an enclosure (102) comprising in a lower part of the enclosure a manufacturing plate (112) and a spreading means (114) of powder capable of traversing the manufacturing plate in order to spread there powder previously deposited on the manufacturing plate and comprising in an upper part of the enclosure a window (108) facing the manufacturing plate and allowing the passage of laser rays (110), the device (100,200) comprising at least one effector arranged in the enclosure and connected to at least two actuators (120) configured to move said effector between the upper part of the enclosure and a target position at the level of the plate (112) the device further comprising at least two effectors each provided with a powder dispenser (116), and in which the powder dispensers (116) comprise different powders. 2. Device (200) according to claim 1, wherein at least one effector is equipped with a powder extractor (124). 3. Device (100,200) according to one of the preceding claims, comprising, for each effector, four actuators (120) arranged in the upper part of the enclosure (102) and each connected by a cable (118,117) to said effector. 4. Device (100,200) according to one of the preceding claims, wherein the build plate (112) extends in a first direction (Y) and a second direction (X) perpendicular to each other, and the build plate ( 112) is movable in a third direction (Z) perpendicular to the first direction and the second direction. 5. Device (100,200) according to claim 4, wherein, for each effector, the actuators (120) are configured to move said effector in the first direction (Y) and/or the second direction (X). 6. Device (100,200) according to one of the preceding claims, wherein the powder spreading means is a scraper (114) or a roller. 7. Use of a manufacturing device (100,200) according to one of the preceding claims, comprising: mounting a powder dispenser (116) to an effector of the device (100,200), moving the powder dispenser (116) to the position target of the build plate (112), deposit a predetermined amount of powder, and sweep the build plate (112) with the powder spreading means (114). 8. Use according to the preceding claim, comprising the steps: replacing the powder dispenser (116) with a vacuum cleaner (126), and vacuuming with the vacuum cleaner (126) around a target position on the build plate