EP4319934A1

EP4319934A1 - Method for the additive manufacturing of a metal part

Info

Publication number: EP4319934A1
Application number: EP22720604.2A
Authority: EP
Inventors: Prigent Serge
Original assignee: Institut de Recherche Technologique Jules Verne
Current assignee: Institut de Recherche Technologique Jules Verne
Priority date: 2021-04-06
Filing date: 2022-04-01
Publication date: 2024-02-14
Also published as: FR3121373A1; WO2022214399A1

Abstract

The invention relates to a method for the additive manufacturing of a metal part (50) on a substrate (2), by adding at least one molten metal layer by layer. The method comprises the following steps: a) step a: depositing the molten metal layer by layer, b) step b: simultaneously with step a), cooling, by means of a cooler (7) that is mobile relative to the substrate (2), a cooling zone (8) located at least around the layer (n-1) deposited immediately prior to the layer currently being deposited (n).

Description

Title: Additive manufacturing process of a metal part Technical field

The present invention relates to the additive manufacturing of a metal part. In particular, the invention relates to a process for the additive manufacturing of a metal part on a metal substrate, in particular a very long substrate. The invention also relates to an additive manufacturing installation for implementing the process as well as a metal part obtained by such a process.

Prior technique

To produce a metal part on a substrate by additive manufacturing, it is known to deposit, layer by layer, on the substrate, a molten metal. However, several problems arise, in particular for very long parts, which are also manufactured on very long substrates.

One of these problems is that the further upwards one moves away from the substrate, as the layers of metal are deposited, the less heat is evacuated in the substrate. However, this heat must be dissipated otherwise there is a collapse of the deposited material. Indeed, poor management of heat flows leads to an imbalance between the injected power and the dissipated power. The consequence on the system is that it becomes anisothermal by a change in temperature until it reaches overheating, making it impossible to manage the temperature between two deposited layers. When the metals used are titanium alloys or nickel-based superalloys, these are refractory and have thermal conduction coefficients of the order of 20 Wm^K ¹ and 10 Wm ^K ¹ respectively. To avoid this overheating and this collapse, it is thus necessary to wait after depositing a layer, for example several minutes, before depositing the next layer, which considerably increases the additive manufacturing time of a part. It is also known to reduce the welding energy, which presents a risk of metal sticking due to lack of dilution of the substrate instead of welding and/or to use a fixed cooled hearth, consisting of a plate or a copper bar, but the fixed sole allows a single geometry.

Another of these problems is linked to the oxidation of the molten metallic material. The metals used are in fact, for example, titanium alloys which are very reactive to oxygen, when they are in the liquid state or in the solid state at a temperature above 200°C, or even nickel-based superalloys reactive to oxygen in the liquid state mainly. It is therefore necessary to carry out metal additive manufacturing away from oxygen, hydrogen, carbon and nitrogen. To solve this problem, it is known to use vacuum enclosures or inerting enclosures or bells or a glove box, that is to say a bell with rubber sleeves for handling or a strap that is i.e. an inert gas diffuser. The large enclosures considerably increase the costs and constraints of additive manufacturing.

Finally, another problem identified relates to the creation of deformations linked to a significant temperature gradient between the layer n-1 previously deposited and the layer n being deposited. Indeed, the local stress relaxation at high temperature, above 700°C, leads to tensile stresses after cooling, according to the SATOH type curve. The SATOH test amounts to establishing a stress curve as a function of temperature over a heating then cooling cycle representative of a welding pass (thermal). This test is carried out at zero or low deformation. It is known to partially compensate for the deformations observed by a machining allowance, which impacts the economic balance. Moreover, it is impossible to correct the strong deformations by machining and the part is then scrapped. It is also known to carry out experimental plans on the impact between width, height and dilution of the deposited layer. The reduction in energy, for example, is often technically favorable but affects the deposition rate and therefore deteriorates the economic balance. Controlling temperature fields is therefore a major technical problem during metal additive manufacturing.

The aim of the invention is thus to propose a process for the additive manufacturing of a metal part which makes it possible to control the temperature fields, to reduce the constraints, the costs and the time necessary for the additive manufacturing of the part, in particular if that -this is of great length.

Disclosure of Invention

Additive manufacturing process

The invention achieves this in whole or in part by means of a process for the additive manufacturing of a metal part on a substrate, by adding at least one molten metal, layer by layer, the process comprising the following steps: a) Step a: depositing the molten metal layer by layer, b) Step b: simultaneously with step a), cooling, using a movable cooler relative to the substrate, a cooling zone located at least around the last deposited layer (n-1) before the layer ( n) being deposited, preferably at least around the layers ranging from the deposited layer (n-5) to the last deposited layer {n-1) before the layer (“) being deposited.

Thanks to the invention, there is a cooler which can move relative to the substrate at least around the layer deposited before the layer being deposited and possibly from the layer or layers previously deposited up to the fifth layer previously deposited. , for example, and optionally of the layer being deposited. This makes it possible to control the temperature of this or these layers, in particular to dissipate the heat to avoid overheating.

By "layer being deposited" is meant the layer whose deposition lasts from the beginning to the end of the deposition of the layer and it is considered that there is no transition period between two deposited layers, but that there is continuity. Thus, there is always a layer being deposited and a final layer deposited (starting from the second layer being deposited), regardless of whether or not the method is continuously implemented.

The cooling according to step b) can begin as soon as the second layer is deposited. The method may nevertheless include a step consisting in cooling the first layer deposited when it is unique and in the process of being deposited.

The cooling zone preferably comprises at least one peripheral zone of the last layer deposited n-1 before the layer being deposited n, transversely thereto, as well as a peripheral zone of at least one part, for example between 1 and 5 layers, over a height of approximately between 2 and 10 mm, of the n-1 layers deposited before the layer being deposited n, and/or a zone located above a peripheral zone of the last layer deposited n-1 over a height comprised between 0 and 10 mm approximately, n being in particular comprised between 1 and 5.

By “mobile cooler relative to the substrate”, it is meant that three embodiments are possible: the cooler is mobile, in particular moves in one direction, for example upwards, and the substrate remains fixed; or the cooler remains fixed and the substrate is mobile, in particular moves in one direction, for example downwards; or alternatively the cooler and the substrate are both mobile, one moving in one direction, eg up and the other moving in the opposite direction, eg down. The cooler can be moved using an automaton or a robot and/or be integral with the welding equipment to move relative to the substrate. .

The cooler is preferably fixed relative to the last layer deposited before the layer being deposited and/or relative to the layer being deposited. It can also be indicated that the cooler can be movable in a synchronized manner with the last layer deposited before the layer being deposited and/or with the layer being deposited.

The chiller can be monobloc. In this case, the cooler may have a shape that can at least partially match the shape of the layer being deposited, at a distance from the latter.

As a variant, the cooler may comprise a plurality of walls, in particular plates, in particular between two and eight, which may be independent, connected to each other or not, and preferably integral in movement. In the case where the cooler comprises a plurality of plates, it can be referred to as being multi-plate. A plate can have dimensions, for example of 50mm*10mm*5mm approximately. Whether the cooler is monobloc or multi-plate, in particular when the cooler is multi-plate, the distance of the cooler can be adjusted vis-à-vis the metallic material of the layers concerned to have the desired temperature for the, in particular each, layer. (s).

The cooler may include one or more walls formed by copper plates incorporating circuits cooled by a cooling liquid, in particular water or heat transfer fluid. The wall(s) of the cooler can be formed by the circuits themselves arranged in a serpentine pattern.

The cooler advantageously belongs to a power-controlled cooling system also comprising a control system.

The chiller coolant temperature, when present, is advantageously controlled by the cooling system control system.

The welding power, generally 5kW, can vary from 500 W to 50 kW depending on the installation. It will be sought to dissipate between 20% and 90% of the energy, which corresponds to approximately an energy to be evacuated, for example comprised between approximately 3kW and 50kW. The temperature of the substrate upstream and at the level of the layers ranging, for example, to a distance of between 1 mm and 50 mm, in particular between 5 mm and 15 mm, preferably equal to approximately 10 mm upstream of the layer being deposited n up to the n-5 layer is advantageously controlled by the cooling system. In particular, the temperature of the substrate, in particular in the zone around the last layer deposited before the layer being deposited and/or the layer being deposited can be controlled to be between ambient temperature and 600°C. It should be noted that the thermal front effectively precedes layer n by a distance of between 1 mm and 50 mm, in particular between 5 mm and 15 mm, preferably equal to approximately 10 mm.

Step a) can be implemented in such a way that the layers are deposited according to a plane that is not parallel to the substrate.

The plane of the layers deposited in step a) then preferably forms an angle substantially orthogonal with respect to the substrate.

The first layer is preferably deposited on a secondary substrate fixed to the substrate, in particular close to one end of the latter and extending in a plane substantially parallel to the plane of the layers which will be deposited and preferably orthogonal to the substrate. Each layer advantageously comprises one end, that is to say a layer edge, welded to the substrate at the time of its deposition.

The cooler can be movable along an axis parallel to the substrate relative to the latter, in particular parallel to a longitudinal axis of the substrate. In this case, the substrate may have support points for the relative movement of the cooler. The substrate can itself form a fixed wall closing the cooling zone on one side.

The method may comprise the step consisting in injecting, using a diffuser, an inert gas into an inerting cell including the cooling zone during all or part of the implementation of steps a) and b) . The inert gas can be injected at least into the cooling zone. The gas can be diffused from an area below the cooling zone, upwards.

Thanks to such a step, the area for inerting can be reduced, while making it possible to avoid oxidation of the deposited metal. This results in reducing the quantity of gas injected solely to the volume around the cooling zone, which makes it possible to reduce, on the one hand, the gas cost and, on the other hand, the gas filling time since the volume to be filling is reduced, time during which we did not produce in the prior art. Additionally, the workpiece and torch can be accessed, even during molten deposition.

The inerting cell can include and surround the cooling zone and at least partially the substrate. The inerting cell can be deployed as the process is implemented. For this, the inerting cell may comprise at least one partition, in particular a movable partition relative to the substrate and/or sliding and/or bellows.

When the inerting cell comprises a movable partition relative to the substrate, the latter and/or the substrate can move, throughout the manufacturing process, so that the upper end of the partition remains at a predetermined, substantially fixed distance from the layer being deposited.

When the inerting cell has at least one sliding partition, the latter can be mounted on rails and slide around the part being manufactured for the duration of the process. The inerting cell can also include several sliding partitions, which slide one by one, relative to the others, to unfold around the part as the process is implemented. Thus, a single partition can be deployed at the start, then, as the process progresses, a second partition is deployed to participate in delimiting the inerting cell, while maintaining a predetermined distance, substantially fixed, between the upper end of the inerting cell and the last layer deposited, etc. until the last layer of the part is deposited.

When the inerting cell has a partition with bellows, the bellows is, at the start of the process, little or not deployed. Then, as the method is implemented, the bellows partition is deployed, in particular upwards, until it reaches a fully deployed state at the end of the production of the part, in particular while maintaining a predetermined substantially fixed distance between the upper end of the bellows partition and the last deposited layer.

The predetermined substantially fixed distance between the upper end of the inerting cell and the last layer deposited may for example be between 10 and 50 cm.

The inert gas can be cooled to a temperature below ambient temperature using a refrigeration unit or by expansion. The temperature of the inert gas can be at least 100°C lower than the temperature of the cooling zone. The flow of inert gas can be greater than or equal to 1 m ³ /h. The gas can be projected on the cooling zone with a speed of at least 0.001 m/s.

The inert gas is preferably chosen from the group consisting of argon, helium and nitrogen. Argon is about 40% denser than air. The diffuser is, for example, a refractory metal or ceramic sinter and makes it possible to create a gaseous zone free of air and compatible with a welding activity of titanium, its alloys and nickel alloys.

One or more flexible curtains can extend, for example, to one or more centimeters or even meters around all or part of the inerting cell.

Thanks to the invention, a relatively small zone is delimited around the part where both the temperature and the gas present are controlled.

The metal is for example chosen from the group consisting of titanium, titanium alloys, nickel-based superalloys and steels.

The metal can be brought before melting in the form of powder, wire, strip, bar, or any other form.

For example, a welding torch is used to deposit the molten metal in step a). The technique can still implement an electron beam, a laser, plasma or arc.

It is possible, thanks to the invention, to produce multiple parts, in particular parts, complex or not, which are very long, for example longer than 1 m, up to 50 m.

In a particular embodiment, the part is formed by depositing layers on a first side of the substrate and by depositing layers on a second side of the substrate, in particular opposite the first side. In this case, the deposition of layers on the first side can be carried out simultaneously with the deposition of layers on the second side. Still in this case, the deposition of layers on the first side is for example carried out symmetrically to the deposition of layers on the second side.

Additive manufacturing facility

Another subject of the invention, according to another of its aspects, is an additive manufacturing installation for the manufacture of a metal part on a substrate, by adding at least one molten metal, in particular for the implementation of the method as defined above, the installation comprising at least one system for supplying and depositing a metal in layer-by-layer melting and a cooling system comprising a movable cooler relative to the substrate delimiting a cooling zone and configured to cool at least the cooling zone located at least around the last layer deposited before the layer being deposited and possibly around the layer being deposited.

The cooler can be movable along an axis parallel to the substrate, relative to the latter.

The installation may include an inert gas diffuser capable of diffusing an inerting gas into an inerting cell comprising at least the cooling zone.

The cooling system may comprise a control system able to control the temperature in the zone delimited by the cooler, the control system being for example able to control the mobility along one or more axes of the cooler, in particular of the walls of the cooler and/or or coolant temperature.

Metal part

Another subject of the invention, according to another of its aspects, in combination with the foregoing, is a metal part obtained using the method as defined above, produced layer by layer on the substrate, each layer s extending in a plane substantially orthogonal to the substrate.

Brief description of the drawings

The invention may be better understood on reading the detailed description which follows, non-limiting examples of implementation thereof, and on examining the appended drawing, in which:

[Fig 1] Figure 1 schematically shows in perspective an example of an installation for the implementation of an additive manufacturing process for a metal part according to the prior art,

[Fig 2] Figure 2 shows, schematically, partially and in perspective, an example of an installation according to the invention, for the implementation of an example of an additive manufacturing process, according to the invention, of a metallic part on a substrate, at the beginning of this one,

[Fig 3] Figure 3 is a view similar to Figure 2, after deposition of a number of layers, [Fig 4] Figure 4 is a view similar to Figures 2 and 3 towards the end of the implementation of the method,

[Fig 5] Figure 5 is an isolated, schematic and perspective view of an example of a one-piece cooler that can be used during the method according to the invention,

[Fig 6] figure 6 represents schematically, partially and in perspective, an installation according to the invention showing another example of positioning of the cooler during the implementation of the method according to the invention,

[Fig 7] Figure 7 schematically shows in perspective another example of implementation of the additive manufacturing process according to the invention,

[Fig 8] Figure 8 schematically shows in perspective another example of implementation of the additive manufacturing process according to the invention,

[Fig 9] Figure 9 schematically shows in perspective another example of implementation of the additive manufacturing process according to the invention,

[Fig 10] Figure 10 shows in longitudinal sectional view, schematic and partial, an example of installation for the implementation of the method according to the invention,

[Fig 11] figure 11 is a view similar to figure 10 of the same installation after deposition of a certain number of layers,

[Fig 12] Figure 12 illustrates in isolation and schematically in sectional view an example of a bellows partition that can be used during the implementation of the method according to the invention,

[Fig 13] figure 13 schematically shows in top view an example of a part that can be obtained using the method of the invention,

[Fig 14] Figure 14 shows in cross section along XIV, schematically, the part of Figure 13, surrounded by the cooler,

[Fig 15] Figure 15 schematically shows in cross section another example of a part that can be manufactured with the method according to the invention,

[Fig 16] Figure 16 schematically shows in cross section another example of a part that can be manufactured with the method according to the invention,

[Fig 17] Figure 17 schematically shows in cross section another example of a part that can be manufactured with the method according to the invention,

[Fig 18] Figure 18 schematically shows in cross section another example of a part that can be manufactured with the method according to the invention, [Fig 19] figure 19 schematically shows in cross section another example of a part that can be manufactured with the method according to the invention, and

[Fig 20] Figure 20 schematically shows in cross section another example of a part that can be manufactured with the method according to the invention.

detailed description

In the remainder of the description, identical elements or identical functions bear the same reference sign. For the purpose of conciseness of the present description, they are not described with regard to each of the figures, only the differences between the embodiments being described.

There is illustrated in Figure 1 an example of implementation of an additive manufacturing process used in the prior art. A molten metal M, for example a molten metal wire, is deposited on a substrate S using a welding torch, in the form of layers C deposited on top of each other on the substrate S, along the longitudinal axis X of it and parallel to it. The substrate S has a great length, for example greater than 1 m. The problems presented above lead, after a certain deposition height, to a collapse of the stack of layers, to the creation of deformations and/or require the process to be interrupted after the deposition of each layer.

FIGS. 2 to 4 represent an example of implementation of the method according to the invention with an installation 1 in accordance with one embodiment of the invention for producing a metal part 50 by additive manufacturing. this example to create a reinforcing rib 11, or stiffener, on a substrate 2 and along the latter. The substrate 2 is very long, for example having a length greater than 1 m. The metal part 50 comprises the rib 11 and the substrate 2. A welding torch deposits molten metal M in the form of layers 14, layer by layer, to form the part.

The installation 1 comprises a cooler 5, mobile relative to the substrate 2, but fixed relative to the layer 14, called n, being deposited at a given moment. In other words, the cooler 5 moves as the layers are deposited to be fixed relative to the layer being deposited.

The cooler 5 delimits a cooling zone 8 during the deposition of the layers 14 as visible in FIGS. 3 and 4, around at least the last layer 14 deposited n-1 and possibly the layer 14 being deposited n in order to obtain an optimum temperature within this cooling zone 8 and to dissipate the heat from the molten metal M deposited layer by layer, as the construction of the metal part 50 progresses.

In the example illustrated, the cooler 5 delimits a cooling zone 8 which surrounds the n-5 layers 14 deposited before the layer 14 during deposition n. The cooling zone 8 comprises at least a peripheral zone of the last layer deposited n-1 before the layer being deposited n, transversely thereto, as well as a peripheral zone of at least part of the n-1 layers, in this example between 1 and 5 layers, over a height of between 2 and 10 mm approximately.

In the example illustrated in Figures 2 to 4, the cooler 5 comprises a plurality of walls forming plates 6, three in number in this example, namely an outer plate 6a, arranged on the opposite side with respect to the substrate 2 and plates 6b and 6c, parallel to each other in this example, laterally surrounding the layers 14 parallel to the axis Y. The plates 6 extend in a vertical plane in the example illustrated, perpendicular to the plane of the layers 14. The cooler 5 is in this multi-plate example. Each plate 6 may consist of a copper plate incorporating circuits cooled by a cooling liquid, in particular water or heat transfer fluid.

As seen in Figures 2, 3 and 4, the cooler 5 is fixed relative to the last layer 14 deposited n-1 before the layer 14 n being deposited, always surrounding the latter as well as possibly the layer being deposited. deposition n and/or one or more preceding layers. The cooler 5 can be fixed to the support of the welding torch and move integrally with it, during the implementation of the process.

In another embodiment not illustrated, it is the substrate 2 which is mobile during the implementation of the method, while the cooler 5 remains fixed, as does the welding torch for example.

The cooler 5 belongs to a cooling system 7 which further comprises a control system 20, shown in dotted lines in FIG. 2, formed for example by a remote computer, making it possible to control the temperature of the plates 6 and therefore of the zone of cooling 8, so that the latter allows cooling of the n-layer or of the n-1 layer and possibly of the layers under the n-1 layer, for example up to the n-5 layer.

In the example illustrated, layers 14 are deposited not parallel to substrate 2 as in the prior art, but at an angle. In this example, layers 14 are deposited perpendicular to the substrate 2 extending along the axis X. Each layer 14 has two opposite edges 9, a free edge 10 and an edge 12 in contact with the substrate 2. The end edge 12 of each layer 14 is soldered to the substrate 2 during the deposition of the layer 14.

In installation 1, as seen, substrate 2 is positioned vertically. It could be arranged in an inclined manner without departing from the scope of the invention.

A secondary substrate 3, visible in FIG. 2, is fixed, for example by welding, close to the lower end of the substrate 2, orthogonal thereto, along an axis Y. The secondary substrate 3 may have a surface of base 4 corresponding to the area of each layer 14 of metal to be deposited during the additive manufacturing process. The base surface 4 can alternatively have a larger surface than that of each layer 14.

The deposited metal is in this example a titanium-based alloy, but it could constitute a nickel-based superalloy or any other weldable metal alloy without departing from the scope of the invention. The metal is brought in the form of wire in this example. The metal M is melted in this example using a welding torch, only part of which is shown for the sake of clarity of the drawing.

In the present case, it is sought to maintain the temperature in the cooling zone 8 at a temperature between ambient temperature and 600°C, in particular between 100°C and 300°C. The respective distances d between the plates 6a and 6b and the respective edges 9 of the deposited layers 14 can be approximately between 0 and 2 mm. Preferably, a contact is ensured between the plates 6a and 6b and the respective edges 9 for an exchange by conduction.

This distance d can be modulated to adjust the temperature within the cooling zone 8 delimited by the cooler 5. It is also possible to modulate the surface of the cooler and its thermal dissipation flux in kW/h.

In this example, the cooler 5 moves in such a way that the cooling zone 8 has a constant volume except for modulation of the distance between the plates 6b, respectively 6c, and the corresponding edge 9 of the deposited layers n-1, etc.

The cooler 5 is multi-plate in the example of FIGS. 2 to 4. In the example of FIG. 5, the cooler 5 is one-piece, having an overall shape and a through opening 21 allowing it to surround the substrate 2 and the layers 14 and to define the cooling zone 8.

In another variant of cooler 5 in multi-plate form, cooler 5 could include a fourth plate 6d parallel to plate 6a but located at the other end of plates 6b and 6c to face the free edge 10 of the rib 11 under construction. This could make it possible to completely close the cooling zone 8 laterally.

Such a plate 6d is present in the embodiment of FIG. 6. In addition, in this example, the cooling zone 8 delimited around the n-1 layer and the previously deposited layers also extends around and above above the layer n being deposited along the longitudinal axis X of the substrate 2.

There is shown in Figures 7 and 8, the possibility of making on either side of the same substrate 2 two ribs 11, referenced 11a and 11b, arranged symmetrically or not with respect to the substrate 2. The technique used for each side is the same as defined above, according to the invention.

In the example of figure 7, the advancement on one side and the other is not the same, the rib IIa being carried out before the other. Two coolers 5 are provided, referenced 5a and 5b. The coolers 5 each comprise only two plates 6b and 6c, and are movable in displacement independently of one another, relative to the substrate 2.

In the example of FIG. 8, the ribs 11a and 11b are formed simultaneously and the coolers 5a and 5b are movable simultaneously. One could even have only one cooler 5 in this embodiment, according to a variant.

The example of Figure 9 illustrates the possibility of depositing a metal not in the form of molten wire but in the form of bars 13 coming to be deposited in the molten state. This makes it possible in particular to increase the rate of deposition of the layers 14.

Thanks to the invention, access to the layers during deposition is not hindered by the cooler 5 which, with the cooling zone 8 that it delimits, only laterally encloses the zone with the n-1 layer deposited. , possibly the layer n being deposited, the layers already deposited underlying and possibly a zone above the layer n being deposited.

There is illustrated in Figures 10 and 11 another example of installation 1 for the implementation of the method according to the invention, comprising, in addition to the cooling system 7, an inerting system 15 with injection of inert gas, in this example consisting of argon. The injection is done in this example from the bottom using a diffuser towards an inerting cell 22 including the cooling zone 8 delimited by the cooler 5 shown in dotted lines, and the zone around this cooling zone 8, in the direction illustrated by the arrows, that is to say upwards.

Figure 10 illustrates the beginning of the implementation of the method according to the invention, the number of layers deposited being low, while Figure 11 represents the installation after implementation of the method on a large number of layers.

In the example of Figures 10 and 11, the inerting cell 22 is delimited by at least one, in particular several partitions 26 which can slide relative to each other telescopically, in order to extend the inerting cell 22 as the process is implemented. The partitions 26 are superimposed laterally at the start. They then extend over a height h equal to the height of a partition 26 in Figure 10. In Figure 11, the partition 26i located outside has slid upwards so that the total height is the height h; greater than the height h. The inerting cell 22 is therefore extended in this example during the implementation of the additive manufacturing process according to the invention.

It is noted that the distance D between the upper end 25 of the inerting cell 22 and therefore of the highest partition 26 and the layer being deposited n can be constant and predetermined during the implementation process according to the invention, having for example a value between 10 and 50 cm.

There may of course be a number of partitions 26, sliding relative to each other, greater than two on each side without departing from the scope of the invention.

In Figure 12, there is shown in isolation a bellows partition 26 partially deployed to allow it to extend in order to delimit the inerting cell 22, in order to replace the partitions 26 of Figures 10 and 11.

In Figures 13 and 14, there is shown a metal part 50 with a rib 11 of pyramidal shape as visible. The deposition of the layers will of course be adapted according to this pyramidal shape. The plates 6 of the cooler 5 can be, as shown in this figure, arranged parallel to the edges 9 of the rib 11.

Other examples of metal parts 50 according to the invention produced according to the method according to the invention have been illustrated in FIGS. 15 to 20. In the example of figure 15, the rib 11 seen from above changes dimension in height and in thickness on the X axis, with a part 17 more massive than the part 16.

In the example of Figure 16, the rib 11 is in the shape of an inverted pyramid.

In the example of Figure 17, the rib 11 comprises two parts 18 and 19 forming an angle between them. In this case, the plates 6 of the cooler 5 can present angles so as to have at any point of the plate 6 a constant distance relative to the edge 9 and possibly 10 of the rib 11.

In the example of Figure 18, the rib 11 has a curved shape. In this case, the shape of the plates 6 will also be adapted to this curved shape to maintain within the cooling zone 8 delimited by the cooler 5 a predetermined temperature range.

In the example of Figure 19, there are two substrates 2 arranged one against the other and each supporting a rib 11 having an angle, in a non-symmetrical manner. We do not depart from the scope of the invention if the ribs 11 are mutually symmetrical.

In FIG. 20, the substrates 2 are separate unlike in FIG. 19. Between the substrates 2, a part of the cooler 5 has been integrated in the form of a plate. The ribs 11 in this example include a protrusion 19.

In all these examples, the shape of the cooler 5 and of the plates 6 is of course adapted to have, in the cooling zone 8, the desired temperature.

The invention is not limited to the examples which have just been described. In particular, an embodiment according to the invention can be that of FIG. 1, including a cooler 5 as described above.

The substrate 2 can be mobile and the cooler 5 can be fixed, during the implementation of the method.

The metal can be in the form of powder, wire, bar, strip or in another form.

Layers 14 can be deposited in an inclined plane that is not orthogonal to the plane of substrate 2. Secondary substrate 3 can form a non-right angle with substrate 2.

Claims

1. Process for the additive manufacturing of a metal part (50) on a substrate (2), by adding at least one molten metal, layer by layer, the process comprising the following steps: a) Step a: depositing in layer by layer the molten metal, b) Step b: simultaneously with step a), cooling, using a cooler (5) movable relative to the substrate (2), a cooling zone (8) located at least around the last deposited layer (n-1) before the layer being deposited (n).

2. Method according to claim 1, in which the cooling zone (8) comprises at least one peripheral zone of the last deposited layer (n-1) before the layer being deposited (n), transversely thereto, as well as a peripheral zone of at least a part of the n-1 layers deposited before the layer being deposited (n), and/or a zone located above a peripheral zone of the last layer deposited (n -1), n being in particular between 1 and 5.

3. Method according to any one of the preceding claims, in which the cooler (5) is in one piece.

4. Method according to one of claims 1 and 2, wherein the cooler (5) comprises a plurality of walls forming plates (6).

5. Method according to the preceding claim, wherein the distance of said at least one plate (6) is adjusted vis-à-vis the metallic material of the layers concerned to have the desired temperature for the, in particular each, layer (s) .

6. Method according to any one of the preceding claims, in which step a) is implemented such that the layers are deposited in a plane not parallel to the substrate (2).

7. Method according to the preceding claim, in which the plane of the layers deposited in step a) forms a substantially orthogonal angle with respect to the substrate (2).

8. Method according to one of the two immediately preceding claims, in which the first layer is deposited on a secondary substrate (3) fixed to the substrate (2) and extending in a plane substantially parallel to the plane of the layers which will be deposited. and preferably orthogonal to the substrate (2).

9. Method according to claim 6 and possibly any one of the preceding claims, wherein the cooler (5) is movable along an axis (X) parallel to the substrate (2) relative to the latter.

10. Method according to any one of the preceding claims, comprising the step consisting in injecting, using a diffuser, an inert gas into an inerting cell (22) including the cooling zone (8) for all or part of the implementation of steps a) and b).

11. Method according to any one of the preceding claims, in which the part (50) is formed by depositing layers on a first side of the substrate (2) and by depositing layers on a second side of the substrate (2) , in particular opposed to the first side.

12. Installation (1) of additive manufacturing for the manufacture of a metal part (50) on a substrate (2), by adding at least one molten metal, in particular for the implementation of the method according to one any of the preceding claims, the installation (1) comprising a system for supplying and depositing a molten metal layer by layer and a cooling system (7) comprising a cooler (5) movable relative to the substrate (2 ) defining a cooling zone (8) and configured to cool at least the cooling zone (8) located at least around the last deposited layer (n-1) before the layer in) being deposited.

13. Installation (1) according to the preceding claim, the cooler (5) being movable along an axis (X) parallel to the substrate, relative to the latter.

14. Installation (1) according to claim 12 or 13, comprising an inert gas diffuser capable of diffusing an inerting gas into an inerting cell (22) comprising at least the cooling zone (8).

15. Metal part (50) obtained using the method according to claim 7 and according to any one of claims I to 5 and 8 to ll, produced layer by layer on the substrate (2), each layer extending in a plane substantially orthogonal to the substrate (2).