Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
  • B22F7/08—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools with one or more parts not made from powder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/20—Direct sintering or melting
  • B22F10/25—Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/30—Process control
  • B22F10/38—Process control to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/50—Treatment of workpieces or articles during build-up, e.g. treatments applied to fused layers during build-up
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
  • B22F7/062—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools involving the connection or repairing of preformed parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K10/00—Welding or cutting by means of a plasma
  • B23K10/02—Plasma welding
  • B23K10/027—Welding for purposes other than joining, e.g. build-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K15/00—Electron-beam welding or cutting
  • B23K15/0046—Welding
  • B23K15/0086—Welding welding for purposes other than joining, e.g. built-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K15/00—Electron-beam welding or cutting
  • B23K15/0046—Welding
  • B23K15/0093—Welding characterised by the properties of the materials to be welded
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/12—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding
  • B23K20/1205—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding using translation movement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/12—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding
  • B23K20/129—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding specially adapted for particular articles or workpieces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/0006—Working by laser beam, e.g. welding, cutting or boring taking account of the properties of the material involved
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/34—Laser welding for purposes other than joining
  • B23K26/342—Build-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y10/00—Processes of additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y80/00—Products made by additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/60—Treatment of workpieces or articles after build-up
  • B22F10/66—Treatment of workpieces or articles after build-up by mechanical means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
  • B22F12/90—Means for process control, e.g. cameras or sensors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F2005/005—Article surface comprising protrusions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P2700/00—Indexing scheme relating to the articles being treated, e.g. manufactured, repaired, assembled, connected or other operations covered in the subgroups
  • B23P2700/12—Laminated parts
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• the present invention relates to the technical field of additive manufacturing.
• this term denotes the set of methods for making by adding material, layer by layer, a physical object from a previously defined digital object.
• additive manufacturing processes are the opposite of material removal or subtractive processes, which make it possible to obtain metal objects from thick plates or hollow cylinders.
• Metal objects can also be obtained from forged blanks or foundry crudes near the ribs.
• the corresponding ratio can be as high as 30: 1, particularly in the field of aeronautics, where it is called "Buy to Fly ratio" in English terminology.
• This technique has many limitations, in particular because it does not allow to produce parts on a non-planar substrate, for example cylindrical.
• the control of the melting is difficult and the deposited material may, after solidification, have defects. That is why it is necessary to practice a nondestructive control of any volume built on the support.
• the object of the invention is to overcome these drawbacks by proposing a radically different and highly efficient solution by introducing one or more intermediate steps of catching of the dimensions during the manufacture of the blank.
• the invention relates to a method of additive manufacturing of a blank of a metal object comprising a stack of superposed layers, from a digital object, said method comprising successive steps of producing a layer by local input of metal material on a support itself metal, combined with a local supply of energy, characterized in that it comprises a step of defining and storing a reference surface for the stack and at least one step of removing the material made dry between two successive layers n and n + 1 of the stack, this step of removing material on the upper face of the layer n to create a reference surface for the deposition of the layer n +1, the distance between the reference surface and the reference surface being substantially constant.
• This method thus makes it possible to overcome the deformations of the metallic support and of the successive layers and to reduce the defects of the surface states during the formation of the stack of layers, to ensure the quality of the blank obtained while optimizing productivity through the use of simplified parameters.
• the removal of dry material prevents contamination from a lubricant and it is efficient.
• the removal of material is of the cryogenic type
• a step is taken to measure the distance between the free face of this layer and the reference surface and at a step of comparison between the measured distance and a threshold value, said removal step of material being performed if the measured distance is greater than said threshold value;
• At least one layer is produced by adding metal powder
• At least one layer is made by adding metal wire
• At least one layer is produced by welding discrete surface elements
• said layer having a predetermined thickness, said discrete surface elements have at least one dimension greater than said thickness;
• said layer is obtained with successively welded elements, a complementary step of dry material removal being carried out after the welding of an element, for at least a part of said elements;
• said layer is obtained by welding a first series of elements, at least two of which are spaced apart, and a second series of elements which are interposed in the space or spaces formed between the elements of the first series, a step complementary dry material removal being provided in said one or more spaces, between the welding of the first series and that of the second series;
• said elements and said support come from the same piece
• the reference surface corresponds to the surface of the support before any step of material supply.
• the invention also relates to a device for the additive manufacturing of a blank of a metallic object comprising a stack of superposed layers, from a digital object, said device comprising means for successively producing a layer by local supply of metallic material. on a support itself metal, combined with a local supply of energy, means for storing a reference surface and means for the removal of material on the upper face of a layer of the stack.
• the invention also relates to a method of manufacturing a metal object from a blank obtained by the method according to the invention, this manufacturing method comprising a step of machining this blank to obtain this metal object. It also relates to a blank of a metal object and a metal object obtained by the methods according to the invention.
• the invention relates to a metallic component of an aircraft obtained by the methods according to the invention, that is to say a component of the structure of the aircraft or its propulsion means.
• FIG. 1 comprises FIGS. 1A to 1E which illustrate the successive deposition of layers by a conventional method of additive manufacturing, with an addition of material in the form of powder or wire.
• FIG. 2 comprises FIGS. 2A to 2E which illustrate the implementation of the method according to the invention on a flat support with a contribution of material in the form of powder or metal wire.
• Figures 3 and 4 are perspective views illustrating the implementation of the method according to the invention on a plane support with a contribution of material in the form of discrete surface elements.
• FIG. 1 schematically illustrates various steps of a conventional method of additive manufacturing comprising depositing four successive layers by adding metallic material to a support 1, to obtain a stack.
• the dotted line 10 materializes the plane in which extends the upper face 11 of the support on which a first layer will be deposited. This plane defines a marker surface that is stored.
• FIG. 1B illustrates support 1 and this first layer 12 which is obtained by a local supply of metal, for example in the form of powder or wire, and energy, for example in the form of a laser beam, a beam of electrons or plasma. It is the same of the different layers that will be described.
• the metal is deposited on the support 1 while it is melt, which causes a deformation of the support.
• FIG. 1B thus shows that the upper face 11 of the support 1 has a concave shape, the concavity of which is turned towards the first layer 12, the maximum height between the upper face 11 and the plane 10 being identified by the height hi.
• the first layer 12 matches the geometry of the support 1 and thus also has a slightly concave shape whose concavity is turned away from the support 1.
• FIG. 1C illustrates the following step in which a second layer 13 is formed on the upper face 120 of the first layer 12, that is to say the face opposite to the support.
• FIG. 1C shows that, during the deposition of the second layer, the deformation of the support 1 and of the first layer 11 is amplified because of the heat provided, the maximum height h 2 between the upper face 11 of the support and the plane 10 being superior to hi.
• the second layer 13 marries, again, the geometry of the first layer 12 and has a greater concavity than the first layer shown in Figure 1B.
• FIG. 1D illustrates the following step of deposition of the third layer 14 on the upper face 130 of the second layer 13, opposite the support 1.
• the deformation of the support 1 is accentuated, the maximum height h 3 between its upper face 11 and the plane 10 being greater than the height h 2 .
• the concavity of the third layer 14 which matches the geometry of the second layer 13 is accentuated.
• FIG. 1E illustrates the deposition of a fourth layer 15 on the upper face 140 of the third layer 14.
• this fourth layer amplifies the deformation of the support and layers already deposited, because of the heat input during the formation of this fourth layer.
• Figure 1E shows that the concavity of the support 1 is accentuated, the height h 4 between the upper face 11 of the support and the plane 10 being greater than .3.
• the fourth layer 15 matches the geometry of the third layer 14.
• the deformation of the assembly obtained can reach several millimeters and requires then a mechanical recovery.
• FIGS. 2A to 2E illustrate an exemplary implementation of the method according to the invention.
• Figure 2A is identical to Figure 1A.
• FIG. 2A illustrates a first step of the method in which a reference surface for the stack is defined and stored.
• This step is performed before any input of matter and energy.
• This reference surface here consists of the upper face 11 of the support 1, before any deposition of metal layer and is represented by the dotted line 10.
• This reference surface therefore remains identical in positioning and in shape throughout the implementation of the method, while the upper face of the support may itself be deformed.
• Figure 2B is similar to Figure 1B and illustrates the deposition of a first layer 21 on the upper face 11 of the support.
• This first layer 21 is made by local supply of metal, for example in the form of powder or wire, and energy, used to heat the material, for example in the form of a laser beam, an electron beam an electric arc or plasma. These two contributions are simultaneous and made close to each other.
• the material supply zone is located at a distance from the energy supply zone of between 0 and 50 mm.
• a local contribution is classically understood as a contribution that is made only at the level of the draft to be produced. This is not particularly the case when powder bed techniques are used.
• the material is moving relative to the support during the supply of energy for melting, since the inputs are made at the same time.
• the support on which the material is made will be part of the blank so that the mass of the blank is greater than that of the mass of metallic material provided.
• the upper face 210 of the layer 21, free face opposite to the support undergoes a step of removing material, such as machining, so as to create a reference surface 211 for the deposition of the layer 22.
• This removal of material is adjusted so that the distance between this reference surface 211 and the reference surface 10 is constant or substantially constant. This is verified throughout the layer 21, or at any point of the reference surface 211.
• the reference surface is plane, as in the example illustrated in FIG. 2, the reference surface 211 is parallel to the reference surface 10.
• the thickness of the layer 21 is not necessarily constant.
• FIG. 2C shows that the thickness is smaller at the periphery of the stack than at its center.
• the method according to the invention produces a blank comprising locally a stack of layers, at least one of which does not have a constant thickness.
• This layer of variable thickness can also be detected on the object obtained after machining the blank.
• This material removal step is performed dry, so as not to pollute the support.
• the removal of material is of the type assisted by a cryogenic fluid, for example liquid nitrogen or CO 2 .
• a cryogenic fluid for example liquid nitrogen or CO 2 .
• the deposition of the second layer 22 on the reference surface 211 causes limited deformation of the support.
• this cryogenic fluid makes it possible to cool the first layer 21 to a temperature that will be substantially constant over the entire layer.
• Another advantage is to achieve the removal of material at the same reference temperature over the entire surface of the first layer and therefore under the same conditions.
• the step of removing material made with a cryogenic fluid makes it possible to create, for a given layer, a geometrical reference with the reference surface and a thermal reference, conferring substantially the same temperature on the whole of the layer, that is to say that the temperature difference between two points of the layer is less than 20%.
• This reference temperature also makes it possible to freeze the microstructure of the formed metal layer and this, over the entire surface of the layer.
• cryogenic fluid also fulfills the role of a machining lubricant, which does not pollute the support.
• a lubricant machining is intended to reduce friction on cutting tools and evacuate a portion of the heat generated by deformation, fracture and friction during cutting.
• a cryogenic fluid necessarily has the effect of evacuating heat efficiently and quickly and without contaminating the support.
• FIG. 2D illustrates a next step of the method, corresponding to the deposition of the third layer 23.
• the upper face 220 of the second layer 22, free face opposite the support 1 is subjected to a material removal step to create a reference surface 221 on which the third layer 23 will be deposited.
• This reference surface 221 is defined such that the distance between this surface 221 and the reference surface represented by the line 10 is constant. This is verified throughout the second layer 22 or at any point of the reference surface 221.
• Figure 2D illustrates the third layer 23, after its deposition on the reference surface 221.
• the material removal step leading to the obtaining of the reference surface 221 is preferably assisted by a cryogenic type fluid.
• the deposition of the third layer 23 generates little deformation of the first and second layers 21 and 22, because of the induced cooling.
• FIG. 2E illustrates the deposition of a fourth layer 24 on the third layer 23.
• this deposit does not intervene on the upper face 230 of the layer 23, that is to say the free face of the layer 23 opposite the support 1.
• a material removal step is provided to create a reference surface 231, on which the fourth layer 24 will be deposited.
• This reference surface is obtained by a step of removing material, preferably assisted by a cryogenic fluid.
• the deposition of the fourth layer 24 causes little deformation of the lower layers, thanks to the cooling induced during the production of the reference surface 231.
• Figure 2E illustrates the stack obtained. It appears that the free face 240 of the fourth layer 24, opposite the support 1, is substantially parallel to the reference surface materialized by the line 10.
• a stack of layers obtained by the method according to the invention does not require a significant mechanical recovery on the side of the upper face of the support, unlike the stack of layers illustrated in Figure 1E and obtained with a classical process. Moreover, it is not useful to deposit excess material to obtain a stack having the desired geometry.
• a material removal step does not occur systematically between two successive layers of the stack.
• the method may consist, after each deposition of a layer, in measuring with a sensor the distance between the free face, opposite to the support, of the last layer of the stack and the surface reference 10. When this distance is greater than a threshold value, previously identified, the material removal step is then implemented to achieve a reference surface.
• Another solution is to model the behavior of the stack during its production, depending for example on the thickness of the substrate, the energy supply or the materials used. This modeling makes it possible to know in advance the deformations induced during the deposition of the successive layers and thus to predict between which layers formation steps a material removal step will be performed to form a reference surface.
• This material removal step may consist of machining or rectification and be performed by conventional devices.
• Mention may in particular be made of machines marketed by Mazak under the trade name HV800, by the company Fives under the name Flexiax. Mention may also be made of a turning machine marketed by Mazak under the name A 16, or a turning and milling machine also marketed by Mazak under the name Integrex 1550 RAM.
• reference surface is not necessarily flat, as in the exemplary implementation of the method illustrated in Figure 2.
• the support can be plane on all its surface or only on a part of its surface. It may also have a non-planar shape, for example a form of revolution in particular cylindrical or may have a left shape.
• the blank that will be obtained at the end of the process will have a shape similar to that of the support, as the final object obtained after machining the blank, for example a truncated cone shape.
• the material removal steps are preferably provided such that at the given point of the layer of the stack on which the material is removed the loss of height is less than the height of the layer. in question.
• the first layer of the stack produced on the support 3 is formed based on discrete surface elements 4 and 4 '.
• the discrete surface elements 4 and 4 ' have an isosceles trapezoidal section.
• the element 4 is defined by two faces 46 forming an isosceles trapezium, with two parallel bases 40 and 41, the length L of the base 40 being greater than the length 1_ of the base 41.
• the two bases 40 and 41 are connected by two sides 42 and 43 having the same inclination with respect to the base 40 and relative to the base 41.
• Each element 4 has a height h corresponding to the distance between the bases 40 and 41. Each element 4 also has a thickness e which is counted between the two faces 46 or in a plane substantially perpendicular to that defined by the height h and the length L or _1.
• the height h and the length L or 1. are greater than the thickness e.
• the height h of the elements 4 is greater than their thickness e.
• the discrete surface elements are then made, for example by cutting in a metal sheet which may be constituted by the support 3 itself.
• FIG. 3 illustrates a first step of the method in which metallic elements 4 are welded to the support 3, also metallic, in a first arc of a circle. This is a T (or L) assembly.
• the elements 4 are welded to the support 3 by their face 47 defined by the bases 40, that is to say along their great length L.
• This step corresponds to a first series of elements 4.
• the welding of the elements 4 can be carried out by any suitable method and in particular a linear friction welding (LFW for Linear Friction Welding in the English terminology) or a process using high temperature plasmas (for example SPS type processes). for Spark Plasma Sintering in terminology English or sputter welding or flash butt welding in English terminology).
• LFW Linear Friction Welding in the English terminology
• SPS high temperature plasmas
• Spark Plasma Sintering in terminology English or sputter welding or flash butt welding in English terminology.
• a linear friction welding process is a solid phase welding process, the materials not being melted, and which does not require filler materials.
• the assembly is performed by rubbing against one another the surfaces to be assembled, under a controlled pressure.
• the advantages of solid state welding are the preservation of the properties of the materials as well as the possibility of assembling between heterogeneous materials.
• a method of the SPS type is based on the use of high temperature plasmas, momentarily generated between powder particles, by an electric discharge.
• the heating and cooling speeds are high and the temperature maintenance is generally short.
• the densification of the material can therefore be done at a relatively low temperature, which qualifies this method of fusion welding process.
• the next step of the process consists of a removal of material, such as machining, on the elements 4.
• the removal of material can also be achieved by grinding.
• This material removal step is performed dry. It may in particular be assisted by a cryogenic fluid, that is to say with a supply of liquid nitrogen or CO2.
• This step of removing material is intended to remove the burrs that may result from the previous welding step and, in general, to prepare the side faces 44 and 45 of the elements 1 already welded which will be in contact and welded together with other elements that will subsequently be welded to the support.
• FIG. 4 illustrates the next step of the method, in which is welded a second series of elements 4 'which are interposed in the spaces formed between the elements 4 of the first series, illustrated in FIG. possible in that all the elements 4, 4 'have the same shape and the elements 4 are spaced a length _1.
• FIG. 4 thus illustrates the elements 4 of the first series and the elements 4 'of the second series which are all welded on the support 3 with the exception of a single element 4'.
• FIG. 4 shows that the elements 4 'are welded on the support 3 by their short length _1, or else by their surface 48' defined between their bases 41 ', and on the faces 45, 44 of the adjacent elements 1 by their faces 45 'and 44'.
• the elements 4 and 4 'are therefore arranged head to tail.
• the elements 4 ' are welded to both the support and the elements 4 by any suitable welding process and, preferably, by a non-fusion welding process, as previously described.
• the layers that will be formed on the layer 30 obtained will be made from discrete surface elements or by adding metal powder or wire.
• the upper face 300 of the layer 30, free face opposite to the support undergoes a step of removal of material, such as machining, so as to create a surface of reference for the deposition of the next layer.
• this removal of material is adjusted so that the distance between the reference surface and the reference surface consisting of the upper face 31 of the support, before any discrete surface element deposition, is constant. This is verified, after creation of the reference surface, throughout the layer 30 or at any point of the reference surface.
• this material removal step is performed dry, so as not to pollute the support.
• this removal of material is of the type assisted by a cryogenic fluid, for example liquid nitrogen or CO2.
• a cryogenic fluid for example liquid nitrogen or CO2.
• cryogenic fluid has the same advantages as those described for the process involving a supply of metal in powder or wire form.
• a layer can be obtained from surface elements having a shape different from that illustrated in FIGS. 3 and 4.
• the upper face of the support on which the material is provided is preferably a finished surface whose dimensions correspond to the metal object obtained by machining the blank made with the method according to the invention.
• the upper face may be devoid of any extra thickness and it will not be necessary to machine it.
• the lower face of the support opposite to the blank, may be machined, in particular to obtain the desired dimension for the object, taking into account the deformations of the support.

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• 2016
  • 2016-07-08 FR FR1656596A patent/FR3053632B1/fr active Active
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