FR3093940A1 - Device for manufacturing by selective fusion on a powder bed - Google Patents

Abstract

The present invention relates to a device (1) for manufacturing a three-dimensional part (2) by selective powder bed melting, the device (1) comprising: a delivery system (5) configured to carry and deliver a bed powder, from a first zone (Z1) not exposed to energetic radiation, to a second zone (Z2) intended to be exposed to energetic radiation, an energy source (4) configured to emit energetic radiation towards the second zone (Z2) in order to selectively merge the bed of powder in the second zone (Z2) to form a layer of the three-dimensional part (2). Figure for the abstract: Fig. 2

Description

Device for manufacturing by selective melting on a powder bed

The present invention relates to selective melting on a powder bed.

The invention relates more specifically to a device for manufacturing a three-dimensional part by selective melting on a powder bed.

Selective melting on a powder bed is an additive manufacturing technique that makes it possible to produce a three-dimensional part by melting successive layers.

Referring to Figure 1, a known device 100 for manufacturing a three-dimensional part 200 by selective melting on a powder bed comprises:
a supply tank 300 movable in upward vertical translation,
a manufacturing platform 400 movable in downward vertical translation,
a galvanometric head 500 configured to emit a laser beam 510 in the direction of the manufacturing platform 400, and
a 600 scraper.

In addition, the assembly formed by the supply tank 300, the manufacturing plate 400 and the scraper 600 is housed within a hermetically sealed chamber 700.

The operation of such a device 100 is sequential. First, the supply tank 300 is moved upwards in order to expose the powder. Then, the scraper 600 is actuated in order to move this powder from the supply tank 300 to the manufacturing plate 400 so as to form a bed of powder at the level of an upper end of the manufacturing plate 400 or, if necessary , of the three-dimensional part 200. Then, the galvanometric head 500 emits a laser beam 510 which melts the powder bed according to a pre-established pattern, in order to form a layer of the three-dimensional part 200 on the manufacturing platform 400. Finally, the build plate 400 is set in downward motion to prepare to receive a new powder bed.

The atmosphere within Chamber 700 is controlled to protect the fusion zone and eliminate volatile fusion residues.

Such a device has for example been described in document FR 3 044 944 in the name of the Applicant.

However, such a device has many drawbacks.

First of all, the spreading speed of the powder bed is such that the manufacturing time of a 200 three-dimensional part is high.

In addition, the residual powder which is not fused by the laser beam 510 comes to be stored on the manufacturing plate 400, as visible in FIG. 1. Consequently, it is necessary to provide an additional step of cleaning the the three-dimensional part 200 and the manufacturing plate 400 in order to eliminate this remainder, which can prove to be long and costly.

In particular, the movement of the scraper 600 participates in generating volatile residues, which is detrimental to controlling the quality of the layers which form the three-dimensional part at the level of the melting zone.

Finally, sequential operation is by nature discontinuous, which leads to loss of time in the production of parts.

There is therefore a need to overcome at least one of the drawbacks of the prior art.

An object of the invention is to improve the manufacture of a three-dimensional part by selective melting on a powder bed.

Another object of the invention is to allow continuous manufacture of a three-dimensional part by selective melting on a powder bed.

Another object of the invention is to eliminate the cleaning of the three-dimensional part once formed, in order to rid it of residues of unfused powder.

For this purpose, according to a first aspect of the invention, a device is proposed for the manufacture of a three-dimensional part by selective melting on a powder bed, the device comprising:
a conveying system configured to carry and convey a bed of powder, from a first zone not exposed to energetic radiation, to a second zone intended to be exposed to energetic radiation,
an energy source configured to emit energetic radiation toward the second area to selectively fuse the powder bed in the second area to form a layer of the three-dimensional part.

Thanks to such a device, it is no longer necessary to provide a scraper to form a bed of powder before each selective fusion, which saves time. In addition, thanks to the conveying system, it is possible to carry out selective melting continuously, as the powder bed passes through the second zone. Finally, by forming the powder bed beforehand, it is possible to directly give it the pre-established pattern, which saves powder, and eliminates the stage of final cleaning of the three-dimensional part.

Advantageously, but optionally, the device according to the invention may comprise one of the following characteristics, taken alone or in combination:
the conveying system is configured to convey the bed of powder according to a first direction of displacement, the device further comprising a first support configured to receive the three-dimensional part, the first support and the conveying system being movable one by one relative to the other in a second direction of displacement, different from the first direction of displacement, in order to displace the three-dimensional part relative to the routing system as successive layers are formed,
the second direction of movement is substantially orthogonal to the first direction of movement,
the conveying system comprises a second support movable relative to the energy source, the second support being configured to receive the bed of powder and to convey the bed of powder from the first zone to the second zone,
the second support comprises a strip capable of being driven in scrolling through the second zone,
the routing system comprises a first roller configured to unwind the tape and a second roller configured to wind the tape in order to advance the tape in the second zone,
the band includes side reinforcements,
it further comprises a loading system configured to deposit the powder bed on the second support,
it further comprises a blower configured to generate a gas flow in the second zone, and
the powder bed comprises an additive suitable for sublimating when it is subjected to energetic radiation, so as to create a gas protecting the powder bed during fusion.

According to a second aspect of the invention, there is proposed a method for manufacturing a three-dimensional part by selective melting on a powder bed, the method comprising steps of:
conveying a bed of powder formed beforehand, from a first zone not exposed to energetic radiation, to a second zone intended to be exposed to energetic radiation,
exposing the second area to energetic radiation to selectively fuse the powder bed in the second area to form a layer of the three-dimensional part.

Advantageously, but optionally, the method according to the invention may comprise one of the following characteristics, taken alone or in combination:
in this process:
the powder bed is conveyed in a first direction of movement, and
the melting of the powder bed leads to the formation of a layer of the three-dimensional part,
the method further comprising a step of moving the three-dimensional part and the bed of powder relative to each other in a second direction of movement, different from the first direction of movement, with a view to forming a new layer of the three-dimensional piece,
in this method, prior to the step of exposing the second zone, the powder bed is brought into contact with the three-dimensional part, and
it includes a prior step of forming the powder bed.

According to a third aspect of the invention, there is proposed an assembly comprising:
a backing strip, and
a powder bed covering at least one face of the support strip,
the powder bed being able to be fused when it is subjected to energetic radiation to produce a layer of a three-dimensional part.

Advantageously, but optionally, the assembly comprises an additive suitable for sublimating when it is subjected to energy radiation, so as to create a gas protecting the powder bed during fusion.

Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, and which must be read in conjunction with the appended drawings in which:

FIG. 1, already described, schematically illustrates a device for manufacturing a three-dimensional part by selective melting on a powder bed which is known from the prior art,

FIG. 2 schematically illustrates a device for manufacturing a three-dimensional part by selective melting on a powder bed, according to a first embodiment of the invention, the device being illustrated in two distinct operating states,

FIG. 3 is a top view of the second zone of a device for manufacturing a three-dimensional part by selective melting on a powder bed, according to a second embodiment of the invention,

FIG. 4 schematically illustrates a device for manufacturing a three-dimensional part by selective melting on a powder bed, according to a third embodiment of the invention, and

FIG. 5 is a flowchart of a process for manufacturing a three-dimensional part by selective melting on a powder bed, according to an example of implementation of the invention.

With reference to FIGS. 2 to 4, a device 1 for manufacturing a three-dimensional part 2 by selective melting on a bed of powder 3 will now be described.

In all that follows, a “three-dimensional piece” designates any element having the three dimensions of space. In other words, a three-dimensional part is an object developing in a three-dimensional space without, a priori , extending along a privileged direction. Such a three-dimensional part can, for example, be a turbine engine fan blade. However, this is not limiting, since such a three-dimensional part could also be a table, or even a motor vehicle rim.

In what follows, “selective melting” refers to an additive manufacturing technique in which material in the solid phase is subjected to energetic radiation until it reaches a liquid phase. Once the energetic radiation is cut off, the liquid phase solidifies so as to form a solid layer of a three-dimensional piece. In any case, selective melting differs from additive manufacturing by stereolithography, in which resin sensitive to ultraviolet radiation is solidified by the passage of a laser layer after layer, according to the principle of photopolymerization.

In what follows, “powder” designates a fractionated state of matter. In other words, powder comprises material in solid form in small pieces, for example spherical beads, typically with a diameter of less than a tenth of a millimeter, for example 10 μm. Thus, a "powder bed" refers to a layer of powder covering a surface. In other words, a powder bed is a layer of loose material in powder form, the characteristic thickness of which, in a directly orthogonal to the surface it covers, is of the order of the characteristic dimension d a unit element of powder, typically the diameter of a spherical ball of powder. In any case, the material in pulverulent form (i.e. the powder) can be metal, typically titanium. However, this is not limiting, since it is also possible to manufacture a three-dimensional part by selective melting on a bed of plastic or ceramic powder.

Power source 4

Referring to Figures 2 to 4, the device 1 for manufacturing a three-dimensional part 2 by selective melting on a powder bed 3 comprises an energy source 4 configured to emit energy radiation in a given direction.

The energy source 4 can be a laser, for example for selective laser melting (or SLM, for "Selective Laser Melting" in English terminology). However, this is not limiting, since the energy source 4 can also be configured to emit an electron beam, for example for electron beam melting (or EBM, for “Electron Beam Melting” in the terminology Anglo-Saxon).

Routing System 5

Referring to Figures 2 to 4, the device 1 for manufacturing a three-dimensional part 2 by selective melting on a bed of powder 3 comprises a conveying system 5 configured to carry and convey a bed of powder 3 having been previously formed, from a first zone Z1 not exposed to energetic radiation, to a second zone Z2 intended to be exposed to energetic radiation, typically that emitted by the energy source 4. Thus, the energy source 4 is configured to emit energetic radiation in the direction of the second zone Z2 in order to selectively fuse the powder bed 3 located in the second zone Z2 to form a layer of the three-dimensional part 2.

“Zone” means a portion of a given space. In other words, the first zone Z1 and the second zone Z2 are two distinct subspaces, each being delimited within a space larger than these two subspaces. In this respect, each of the first zone Z1 and of the second zone Z2 can have any type of shape and/or dimension.

Likewise, the term "previously formed" denotes the fact that the powder bed 3 is formed before the conveying system 5 can convey it from the first zone Z1 to the second zone Z2. In other words, the conveying system 5 is not configured to form the powder bed 3, for example by spreading on a support by means of a scraper. On the contrary, the conveying system 5 is configured to receive a bed of powder 4, and to make it pass from the first zone Z1 to the second zone Z2.

Referring to Figures 2 to 4, the conveying system 5 is advantageously configured to convey the powder bed 3 in a first direction of movement X-X. Furthermore, the device 1 advantageously comprises a first support 6 configured to receive the three-dimensional part 2 as it is manufactured. As visible in Figures 2 to 4, the first support 6 can be a plate 6, movable in vertical translation. In any case, as visible in Figures 2 to 4, the first support 6 and the routing system 5 are then advantageously movable relative to each other in a second direction of movement Y-Y, different from the first direction of movement X-X, in order to move the three-dimensional part 2 relative to the routing system 5 as successive layers are formed. In a non-limiting embodiment illustrated in Figures 2 to 4, the first direction of movement X-X is substantially orthogonal to the second direction of movement Y-Y.

Still with reference to FIGS. 2 to 4, the routing system 5 can also comprise a second support 50, movable relative to the energy source 4. In this embodiment of the device 1, the second support 50 is then configured to receive the powder bed 3 previously formed, and to convey the powder bed 3 from the first zone Z1 to the second zone Z2.

Alternatively, or in addition, the second support 50 can comprise any type of material capable of supporting the powder bed 3, typically paper, fabric, a polymer, synthetic fiber, or even a gel. These materials can also be used alone or in combination to form the second support 50. Typically, a second support 50 formed from a composite material of fibers and paper advantageously provides a tear-resistant support. However, this is not limiting, since the second support 50 can also comprise mylar, for example when the characteristic dimension of the powder grains is reduced.

The powder bed 3 can be placed on the second support 50, on one or the other of the faces 501, 502 of the second support 50. Advantageously, as can be seen in FIGS. 2 to 4, the powder bed 3 is placed on a face 501 of the second support 50 which is intended to be exposed to the energetic radiation of the energy source 4 during its passage through the second zone Z2. In this case, the second support 50 undergoes melting at the same time as the powder to form a layer of the three-dimensional part 2, so that a slot 503 is formed in the second support 50 after it has passed through the second zone Z2. Alternatively, the powder bed 3 is arranged on a face 502 of the second support 50 opposite, in the direction of the energy radiation, to the face 501 which is intended to be exposed to the energy radiation of the energy source 4 during its passage. in the second zone Z2. In this case, the second support 50 is advantageously inert to energy radiation (e.g. transparent), so as not to alter the properties of the energy radiation when passing through the second support 50 to fuse the powder bed 3.

The powder bed 3 can be placed on the second support 50 according to a pre-established pattern. Typically, as seen in Figure 3, the second support 50 may successively comprise along the first direction of movement X-X, powder beds 3 of particular shape corresponding to the shape of the layer of the three-dimensional part 2 intended to be manufactured . Such preforms make it possible in particular to fuse only the quantity of powder strictly necessary for the formation of the successive layers, which allows advantageous savings. However, this is not limiting, since the powder bed 3 can be uniformly distributed over the second support 50. In this case, the powder remains on the second support 50 after it has passed through the second zone. It is then possible to again pass the second support 50 within the second zone Z2 in order to fuse the remaining powder.

The powder bed 3 can be fixed by gluing on the second support 50. This is however not limiting, because the powder bed 3 can also be integral with the second support 50. In this case, the second support 50 itself comprises powder, for example in agglutinated form.

The powder bed 3 can also be placed on the second support 50 according to a particle size gradient, that is to say the powder bed 3 can comprise grains of different characteristic dimensions depending on their position on the second support 50. It is then possible to merge successive layers of different thickness, the thickness being understood here along a direction orthogonal to the first direction of displacement X-X. Low-thickness thin layers are fabricated for the areas of 3-D Part 2 that require the most precision, while heavy-thickness thick layers are fabricated for areas of 3-D Part 2 that are coarser. This manufacturing modularity thus allows an advantageous saving in manufacturing time.

Advantageously, the powder bed 3 comprises an additive suitable for sublimating when it is subjected to energy radiation, so as to create a gas protecting the powder bed 3 during melting.

In an advantageous embodiment variant illustrated in FIGS. 2 to 4, the second support 50 comprises a strip 50 capable of being driven in scrolling through the second zone Z2. Advantageously, the strip 50 includes lateral reinforcements 504, 505 to prevent it from tearing during scrolling, in particular when the selective melting leads, little by little, to the formation of slots 503 within the strip 50.

By "strip" is meant a piece of material of elongated and narrow shape. In other words, a strip designates a three-dimensional part of which one dimension (i.e. the length) is much greater than the other two (i.e. the width and the thickness), one of the remaining dimensions (i.e. the thickness) being, as for it , reduced in relation to the other remaining dimension (i.e. the width). In this case, the strip 50 of the routing system 5 extends along its length in the first direction of movement X-X, its width and its thickness being substantially orthogonal to the first direction of movement X-X.

It is possible to independently manufacture the assembly comprising a support strip 50 and a powder bed 3 covering at least one face 501, 502 of the support strip 50, the powder bed 3 being able to be fused when it is subjected to energy radiation to manufacture a layer of a three-dimensional part 2. More precisely, a user of the device 1 can obtain such an assembly according to his particular needs for the manufacture of a three-dimensional part 2. The manufacturer of such a together is in fact able to adapt the following manufacturing: the material of the support strip 50, the dimensions of the support strip 50, the presence or not of a preform for the powder bed 3, the presence or not of a particle size gradient, the inert nature or not of the support strip 50 with respect to the energy radiation, the means for fixing the bed of powder 3 on the support strip 50, and/or the face 501, 502 of the strip of support 50 on which the bed of powder 3 is fixed. The manufacture of such an assembly can moreover be implemented according to printing techniques used in other fields, such as the field of newspaper printing .

Returning to Figures 2 to 4, the routing system 5 advantageously comprises a first roller 51 configured to unwind the strip 50 and a second roller 52 configured to wind the strip 50 in order to scroll the strip 50 in the second zone Z2. The first roller 51 and the second roller 52 can moreover be movable in the second direction of movement Y-Y, while the first support 6 is fixed. Alternatively, the first roller 51 and the second roller 52 can be fixed, and the first support 6 is movable in the second direction of movement Y-Y.

A mode of operation of a device 1 for manufacturing a three-dimensional part 2 by selective melting on a powder bed 3 illustrated in FIGS. 2 to 4 will now be described.

The first roller 51 and the second roller 52 are rotated in the same direction so as to cause the support strip 50 to pass. A first bed of powder 3 is then conveyed from the first zone Z1 to the second zone Z2. The rotation of the first roller 51 and of the second roller 52 is then stopped. The plate forming the first support 6 and the rollers 51, 52 are then set in motion relative to each other in the second direction of movement Y-Y, so as to bring the production plate 6 into contact or, if necessary , the last fabricated layer of the three-dimensional part 2, with the support strip 50, which is thus put under tension. This tensioning ensures that the formation of the additional layer from the first powder bed 3 is implemented uniformly. The energy source 4 is then actuated, and the first powder bed 3 as well as, where applicable, the support strip portion 50 supporting this first powder bed 3, is selectively fused to form the layer of the three-dimensional part 2 Then, the plate forming the first support 6 and the rollers 51, 52 are set in motion relative to each other in the second direction of movement Y-Y, so as to give the support strip 50 its freedom of movement. The first roller 51 and the second roller 52 are then again set in rotation in the same direction so as to cause the support strip 50 to pass. A second powder bed 3 is then conveyed from the first zone Z1 to the second zone Z2, while the support strip portion 50 supporting the first powder bed 3 or, where appropriate, the aperture 503 corresponding to the imprint of the first powder bed 2, is routed out of the second zone Z2. Another additional layer is then formed using the same process. The steps are then repeated successively until the complete scrolling of the support strip 50. At this stage, as visible in Figures 2 and 4, the three-dimensional part 2 is manufactured in whole or in part, and rests on the plate 6.

Advantageously, the first roller 51 and the second roller 52 are then rotated in an opposite direction, so as to cause the support strip 50 to travel in the opposite direction, and still in the first direction of movement X-X. The same steps can then be repeated in this direction to selectively fuse the remaining powder on the support strip 50.

Also advantageously, it is possible not to stop the rotation of the rollers 51, 52 and to maintain the support strip 50 under tension of the first plate 6 throughout the selective melting. In other words, it is possible to carry out selective merging continuously. Indeed, when the width of the powder bed pattern 3 to be merged is sufficiently small compared to its length, the manufacture of successive layers can be implemented without the plate 6 and the support strip 50 being separated. In this case, it may be the plate 6 which is movable in a third direction distinct from the first direction of movement X-X and from the second direction of movement Y-Y, in order to give a shape to the three-dimensional part 2. Typically, in the case of the manufacture of a turbomachine fan blade, the plate can pivot around the axis defined by the second direction of movement Y-Y, as the melting progresses, in order to confer a given profile on the tip of the blade 'dawn.

In any event, during the operation of the device 1, only the fused powder is detached from the second support 50, so that it is no longer necessary to clean the first support 6 and/or the three-dimensional part 2 by from manufacturing to rid them of residual powder.

Loading system 7

Referring to Figure 4, the device advantageously comprises a loading system 7 configured to place the powder bed 3 on the second support 50.

The loading system 7 is advantageously arranged upstream of the first zone Z1. The upstream is defined here with respect to the direction of transport of the powder bed 3 from the first zone Z1 to the second zone Z2. The loading system 7 can then be configured to form a bed of powder 3 according to a pattern, a grain size, a thickness, a width and/or a pre-established distribution.

Advantageously, as seen in Figure 4, the loading system 7 comprises a tank 70 configured to allow the spill of powder on the second support 50, for example by means of a hatch (not shown) piloted in the bottom of the tank 70 .

Wind tunnel 8

Referring to Figures 2 to 4, in one embodiment, the device 1 comprises a blower 8 configured to generate a gas flow 80 in the second zone Z2.

The gas flow 80 makes it possible to evacuate the volatile melting residues as the successive layers are formed. To do this, the gas flow 80 can be directed along the first X-X displacement direction, as seen in Figures 2 and 4, or along a direction orthogonal to the first X-X displacement direction. This is however not limiting, since the gas flow 80 can be oriented in any direction, as long as it passes through the second zone Z2.

In addition, the gas flow 80 can be generated by the blower 8 in a continuous or pulsed manner, depending on the configuration of the second zone Z2, the nature of the powder bed 3, and/or the shape of the three-dimensional part 2.

Advantageously, the second zone Z2 is located in a hermetically sealed enclosure 9. This makes it possible to improve the control of the atmosphere of the second zone Z2 during the implementation of the manufacture of the three-dimensional part.

Manufacturing process E

With reference to FIG. 5, a method E for manufacturing a three-dimensional part by selective melting on a powder bed will now be described.

Such a method E can, in a non-limiting manner, be implemented by a device 1 according to any one of the embodiments previously described.

The method E comprises a step E1 of conveying a previously formed powder bed, from a first zone not exposed to energetic radiation, to a second zone intended to be exposed to energetic radiation. Advantageously, the process E comprises a preliminary step E0 of forming the powder bed.

Method E further comprises a step E3 of exposing the second zone to energetic radiation in order to selectively fuse the powder bed located in the second zone to form a layer of the three-dimensional part. Insofar as the fusion selection is implemented on a previously formed powder bed, it is no longer necessary to provide a step for spreading the powder bed from a supply reservoir. In this way, process E can be accelerated.

Advantageously, the powder bed is routed along a first direction of movement, and its fusion leads to the formation of a layer of the three-dimensional part. The method E then comprises a step E4 of moving the three-dimensional part and the powder bed relative to each other in a second direction of movement, different from the first direction of movement, with a view to forming a new layer of the three-dimensional piece. In this way, it is possible to pass powder beds successively along the first direction of displacement, and to allow the three-dimensional part to grow, layer by layer, along the second direction of displacement, as it is manufactured.

During an advantageous implementation, prior to step E3 of exposing the second zone to energetic radiation, the powder bed is brought into contact E2 with the three-dimensional part. In this way, we ensure that the three-dimensional piece does not include empty spaces that could weaken its structure.

Claims (13)

Device (1) for manufacturing a three-dimensional part (2) by selective melting on a powder bed (3), the device (1) comprising:
a conveying system (5) configured to carry and convey a bed of powder (3) from a first zone (Z1) not exposed to energetic radiation, to a second zone (Z2) intended to be exposed to a energy radiation,
an energy source (4) configured to emit energetic radiation toward the second area (Z2) to selectively fuse the powder bed (3) in the second area (Z2) to form a layer of the part three-dimensional (2). Device (1) according to Claim 1, in which the conveying system (5) is configured to convey the bed of powder (3) according to a first direction of movement (X-X), the device (1) further comprising a first support (6) configured to receive the three-dimensional part (2), the first support (6) and the routing system (5) being movable relative to each other in a second direction of movement (Y-Y), different from the first direction of movement (X-X), in order to move the three-dimensional piece (2) relative to the routing system (5) as successive layers are formed. Device (1) according to Claim 2, in which the second direction of displacement (Y-Y) is orthogonal to the first direction of displacement (X-X). Device (1) according to one of Claims 2 and 3, in which the routing system (5) comprises a second support (50) movable relative to the energy source (4), the second support (50) being configured to receive the powder bed (3) and to convey the powder bed (3) from the first zone (Z1) to the second zone (Z2). Device (1) according to claim 4, in which the second support (50) comprises a strip capable of being driven in scrolling through the second zone (Z2). Device (1) according to claim 5, wherein the transport system (5) comprises a first roller (51) configured to unwind the tape and a second roller (52) configured to wind the tape in order to advance the tape in the second zone (Z2). Device (1) according to one of Claims 5 and 6, in which the strip comprises lateral reinforcements (504, 505). Device (1) according to one of Claims 4 to 7, further comprising a loading system (7) configured to deposit the powder bed (3) on the second support (50). Device (1) according to one of Claims 1 to 8, further comprising a blower (8) configured to generate a gas flow (80) in the second zone (Z2). Set including:
a powder bed (3), and
a device (1) according to one of claims 1 to 9,
wherein the powder bed (3) comprises an additive capable of sublimating when subjected to energetic radiation, so as to create a gas protecting the powder bed (3) during melting. Process (E) for manufacturing a three-dimensional part by selective melting on a powder bed, the process (E) comprising steps of:
prior formation (E0) of a powder bed,
routing (E1) of the previously formed powder bed, from a first zone not exposed to energetic radiation, to a second zone intended to be exposed to energetic radiation,
exposing (E3) the second area to energetic radiation to selectively fuse the powder bed in the second area to form a layer of the three-dimensional part. Process (E) according to claim 11, in which:
the powder bed is conveyed in a first direction of movement, and
the melting of the powder bed leads to the formation of a layer of the three-dimensional part,
the method further comprising a step of moving (E4) the three-dimensional part and the powder bed relative to each other in a second direction of movement, different from the first direction of movement, with a view to forming a new layer of the three-dimensional piece. Method (E) according to one of Claims 11 and 12, in which, prior to the step of exposing (E3) the second zone, the powder bed is brought into contact (E2) with the three-dimensional part.