WO2019239169A1

WO2019239169A1 - Method and apparatus for producing a 3-dimensional metal object, in particular a 3-dimensional solid metal object

Info

Publication number: WO2019239169A1
Application number: PCT/HU2019/050029
Authority: WO
Inventors: Péter Tamás TURÁNYI
Original assignee: Al-Bohacen Kft.
Priority date: 2018-06-12
Filing date: 2019-06-12
Publication date: 2019-12-19
Also published as: HUP1800205A2; EP3807032A1; HU231144B1; EP3807032A4

Abstract

The object of the invention relates to a method for producing a 3- dimensional metal object (100), particularly a 3-dimensional solid metal object (100), during which the metal object (100) is built in a vacuum using one or more metal wires (16) of different material quality that have an end 16' by: - providing a sealed work space (12) enclosing a work platform (20), - inserting the end (16') of the one or more metal wires (16) into the work space (12), - producing a vacuum in the work space (12), - placing the end (16') of the metal wire (16) above the work platform (20), - melting the end (16') of the metal wire (16) in the work space (12) with a laser beam (31) to create a molten metal unit (17), and - on the work platform (20) building a 3-dimensional metal object (100) in contact with the work platform (20) from the continuously solidifying molten metal units (17) by moving the work platform (20) and the end (16') of the metal wire (16) relative to one another The object of the invention also relates to an apparatus (10) particularly for implementing such a method.

Description

Method and apparatus for producing a 3-dimensional metal object, in particular a 3-dimensional solid metal object

The object of the invention relates to a method for producing a 3- dimensional metal object, particularly a 3-dimensional solid metal object.

The object of the invention also relates to an apparatus for producing a 3- dimensional metal object, particularly a 3-dimensional solid metal object.

Three-dimensional printing is a revolutionary technology of recent decades that may transform the structure of industry in the near future (fourth industrial revolution). Three-dimensional printing is a so-called additive production process, in other words the objects to be manufactured are produced by placing layers of material on top of one another, as opposed to conventional methods, during which the superfluous material is separated from one or more larger pieces and the remaining part will be the finished product. With 3-dimensional printing it is even possible to create complex shapes and small-series components (e.g. prototypes) that cannot be made or made economically using conventional machining processes.

A high degree of development has been seen in recent years mainly in the field of the 3-dimensional printing of plastics. Several types of technology exist at present that basically differ from each other in terms of how the individual layers are built onto each other. In the case of plastics, one of the most widespread methods is so-called fused deposition modelling (FDM) 3-dimensional printing. During this a hot printing head moves horizontally above the printing surface and an extruder pulls fibres of plastic into the head from a roll, which the plastic melts and deposits onto the work platform through a nozzle. This process is repeated until all the layers are printed. Another widespread method is the so-called selective laser sintering (SLS), during which the 3-dimensional object is created by a laser melting plastic in a powder state. These methods have an increasing number of amateur users. The printing of various plastic household accessories and replacement parts has become increasingly popular and cheap.

However, there has been no significant breakthrough in the field of the 3- dimensional printing of metals, which is still being expensive and time-consuming, in addition their quality, in many cases, is well under that of products produced using conventional production technologies. At present, selective laser melting (SLM) and direct metal laser sintering (DMLS) are the two most popular 3-dimensional metal printing processes, both of which belong to the group of so-called powder bed fusion 3-dimensional printing processes. The two technologies display many similarities, as in both cases a laser is used to melt metal powder particles, and the metal object is built per layer from the melted metal powder. The greatest difference between the SLM and DMLS technologies is that SLM uses a single metal to make the metal objects and DMLS uses a metal alloy.

During the SLM and DMLS processes a closed chamber is first filled with an inert gas (such as argon) in order to minimise oxidation of the metal powder. A thin layer of metal powder is distributed on the work platform, then a high-output laser scans and melts the metal particles to conform with the shape of the object to be printed, in this way producing the first layer. When this scanning has been completed, the work platform moves downwards by a distance equal to the thickness of one layer and the recoater distributes another thin layer of metal powder on the top. The process is repeated until the metal object is finished. Any superfluous powder is removed when the system has cooled to room temperature.

A major disadvantage of the aforementioned processes is that, as a homogenous metal powder is used, it is not possible to use them to produce metal objects consisting of various metals or metal alloys. A further disadvantage is that the metal powder used is extremely expensive, for example, 1 kilogram of stainless steel (316L) costs 350 to 450 dollars, in addition, as a result of the unique characteristics of the technology, a significant proportion of the powder used goes to waste. Among the disadvantages it is important to highlight that due to the powder state of the metal the material structure characteristics of the finished product fall well below those of the metal components produced using conventional (e.g. casting) technologies. For example, the metal powder particles do not receive the same magnitude of energy impulses from the laser due to the obstructions, as a result of this the temperature of the melted particles will not be homogenous and so they do not solidify evenly, and do not create a material with a homogenous structure. Components printed from metal powder contain voids (microscopic air bubbles), due to which their uses are limited.

Patent document number CN 107282925 presents an apparatus and method for the printing of 3-dimensional metal objects, which apparatus contains an airtight protective case delimiting a work chamber, a dispensing head for feeding the metal wire and a work platform that can be moved in space relative to each other, as well as a laser source for producing a laser beam adapted for melting the end of the metal wire in the work chamber. In the case of this solution the printing of the metal object takes place in an inert gas. The laser output necessary for printing is achieved by preheating the metal raw material. The disadvantage of preheating is that in this way the metal raw material is near to its annealing temperature, which may lead to the deterioration of the structural characteristics of the printed finished product. Another disadvantage is that the finished product will not be free of voids due to the inert gas or air present in the work chamber.

Patent documents numbers CN 106363920, CN 104384514 and CN 104874794 present further 3-dimensional metal printing methods.

It was recognised that there is currently no 3-dimensional metal printing technology capable of producing 3-dimensional metal objects in a time and cost- effective way, at a quality level comparable to conventional machining processes.

The invention is based on the recognition that by using one or more metal wires as building raw material instead of metal powder, and by melting the one or more metal wires in a vacuum with a laser, a void-free, 3-dimensional metal object can be produced even from several types of metal or metal alloy in a shorter time and with lower costs than in the case of the current solutions.

It was recognised that during the melting of the one or more metal wires with a laser in a vacuum, the heat transmitted by the laser, in the lack of a contact medium, is unable to dissipate appropriately, which may lead to the annealing of the material of the metal object, and, due to this, to the deterioration of its mechanical properties.

It was recognised that the aforementioned heat transmitted by the laser can be dissipated by regulating the temperature of the work platform in contact with the metal object, and the temperature of the metal object can be maintained at the value optimal from the point of view of printing.

The object of the invention is to provide a method for producing a 3- dimensional metal object, and to provide an apparatus for producing a metal object that is free of the disadvantages of the solutions according to the state of the art.

The object of the invention is solved by the method according to claim 1 . The object of the invention is also solved with the apparatus according to claim 4 for producing a 3-dimensional metal object, particularly a 3-dimensional solid metal object.

Individual preferred embodiments of the invention are defined in the dependent claims.

Further details of the invention will be explained by way of exemplary embodiments with reference to the figures, wherein

Figure 1 a depicts a schematic perspective view of a first exemplary embodiment of an apparatus according to the invention,

Figure 1 b depicts a schematic perspective view of a second exemplary embodiment of an apparatus according to the invention,

Figure 1 c depicts a schematic perspective view of a third exemplary embodiment of an apparatus according to the invention,

Figure 2 depicts a schematic view of an exemplary embodiment of a dispensing head according to the invention,

Figure 3 depicts a schematic side view of an exemplary embodiment of a heating-cooling module according to the invention.

Figure 1 a shows a schematic perspective view of a first exemplary embodiment of an apparatus 10 according to the invention. The apparatus 10 serves to create 3-dimensional metal objects 100, particularly a 3-dimensional solid metal object 100. In the context of the present invention metal object 100 is understood to mean practically any hollow or solid structured 3-dimensional shape made from one or metals or metal alloys (e.g. machine components, decorative objects, etc.).

The apparatus 10 according to the invention contains a vacuum chamber 14 delimiting a sealed work space 12, in the vacuum chamber 14 a dispensing head 18 for feeding one or more metal wires 16 and a work platform 20 are arranged so that they may move in space relative to each other. The vacuum chamber 14 is preferably made from solid, hermetically sealing panels, such as metal, plastic, glass, etc. In the case of a preferred embodiment the vacuum chamber 14 delimiting the work space 12 is made at least partly to be transparent or translucent to visible light, which makes it possible for the operator of the apparatus 10 to observe the work space 12. Naturally, optionally, embodiments are conceivable in the case of which the vacuum chamber 14 does not contain transparent or translucent parts permitting observation of the work space 12. In this case observation of the work space 12 may be performed in another way, such as with one or more cameras located in the work space 12.

A manipulation opening 13 is formed on the vacuum chamber 14 enabling manipulation preferably in the work space 12, such as insertion of the metal wire 16 or removal of the finished metal object 100. The vacuum chamber 14 is for maintaining the vacuum created in the work space 12. For the purpose of clarity, vacuum is understood to mean an evacuated volume that only contains a practically negligible amount of material, therefore the pressure in it is substantially lower than normal air pressure.

The metal wire 16 may be made from pure metal (e.g. aluminium, titanium, etc.) or from a metal alloy (e.g. steel, aluminium alloy, etc.). The metal wire 16 may have a circular, rectangular or any desired cross-section, and the size of its diameter may extend in a range from a tenth of a millimetre or even less than that up to several millimetres. The metal wire 16 has a free end 16’ and is preferably wound up in the form of a reel. The length of the metal wire 16 may even be as long as several metres. The metal wire 16 is dispensed with the dispensing head 18 arranged in the sealed work space 12, which may be, for example, a roller device similar to the wire feeders used in welding technology, as known to those skilled in the art. In the case of a particularly preferred embodiment, the dispensing head 18 is formed so as to be adapted for feeding several metal wires 16, as it can be seen in figure 2, for example. The advantage of this will be explained in detail below. Feeding of the metal wire 16 is understood to mean the intermittent or continuous forwards movement of the end 16’ of the metal wire 16, and, preferably, its unwinding from the reel. The dispensing head 18 preferably contains one or more electric motors, with which the feeding of the metal wire 16 may be controlled remotely.

The work platform 20 according to the invention arranged in the work space 12 is made from a material of appropriate strength, with a suitably high melting point, preferably with good heat conductance, preferably metal (such as steel, titanium, etc.). The work platform 20 has a planar surface 20’ in contact with the metal object 100 to be printed for providing support for it. The planar surface 20’ may have a rectangular, circular, etc. shape, for example.

The apparatus 10 according to the invention contains a laser source 30 for producing a focussed laser beam 31 adapted for melting the end 16’ of the metal wire 16 located in the work space 20. The laser source 30 is preferably created as a solid-state impulse laser known in the art, such as those used in laser welding (e.g. YAG or Fiber laser) or as a gas laser (e.g. CO2 laser). In the case of a possible embodiment the laser source 30 is arranged inside the vacuum chamber 14, in the work space 12 (see figure 1 a, for example). The laser source 30 is configured so that the focus point of the laser beam 31 produced falls substantially at the end 16’ of the metal wire 16, in its immediate environment. As a result of this the laser beam 31 is capable of transmitting sufficient energy to the metal wire 16 so that the end 16’ melts. In the case of a preferred embodiment, the output of the laser source 30 may be controlled, due to this the laser output may be adjusted to comply with the various qualities of the metal wire 16 material (e.g. aluminium, steel, copper, lead, etc.), optionally to comply with the various melting temperatures of the metal wires 16. Accordingly, the maximum output of the laser source 30 is selected so that the generated laser beam 31 is able to melt the material of the one or more metal wires 16 used.

In the case of another possible embodiment shown in figure 1 b, the laser source 30 is arranged outside the vacuum chamber 14, and the vacuum chamber 14 is provided with a window 15 that lets through the laser beam 31 emitted by the laser source 30 and allows the laser beam 31 to penetrate the sealed work space 12. The window 15 may be made from a special glass that transmits at the frequency of the laser source 30 (such as gallium arsenide in the case of a CO2 laser, or Sl- glass in the case of a YAG laser), as is obvious for a person skilled in the art.

The dispensing head 18 and work platform 20 of the apparatus 10 according to the invention are movable in 3-dimensional space relative to one another. In the case of the embodiment shown in figure 1 a, the apparatus 10 contains a second moving device 42 connected to the work platform 20 for moving the work platform 20 relative to the dispensing head 18 in 3-dimensional space. The moving device 42 may be formed as any known (e.g. rail, roller, robot arm, etc.) moving device that is adapted for the precise movement of the work platform 20, preferably with a degree of precision of a tenth of a millimetre. The moving device 42 preferably contains one or more actuators (such as an electric motor, piezoelectric stepper motor, etc.) with which the movement of the work platform 20 can be remotely controlled. If the moving device 42 is created to be adapted for the 3-dimensional spatial movement of the work platform 20, the dispensing head 18 may even be fixed relative to the other parts of the apparatus 10, such as to the wall of the vacuum chamber 14, as in this case the spatial movement of the dispensing head 18 and the work platform 20 relative to each other may only be implemented by moving the work platform 20.

In the case of another possible embodiment shown in figure 1 b, the apparatus 10 contains a first moving device 41 connected to the dispensing head 18 adapted for moving the dispensing head 18 relative to the work platform 20 in 3- dimensional space. The first moving device 41 may be formed, for example, as a moving device known in the art (e.g. rail, roller, robot arm, etc.) similar to the second moving device 42. It should be noted that if the moving device 41 is created to be adapted for the 3-dimensional spatial movement of the dispensing head 18, embodiments are conceivable in the case of which the work platform 20 is fixed relative to the other parts of the apparatus 10, such as the wall of the vacuum chamber 14, and the spatial movement of the dispensing head 18 and the work platform 20 relative to each other is implemented only by moving the dispensing head 18. Similarly to the moving device 42, the moving device 41 preferably contains one or more electric actuators (such as an electric motor, piezoelectric stepper motor, etc.), with which the movement of the dispensing head 18 may be controlled remotely.

In addition to the moving methods presented above, embodiments are conceivable in the case of which a separate moving device is connected to each of the dispensing head 18 and the work platform 20 (see figure 1 c). In this case it is not absolutely necessary to create the moving devices 41 , 42 as 3-dimensional moving devices, as they together ensure the spatial (3-dimensional) movement of the dispensing head 18 and the work platform 20 relative to each other. For example, the moving device 42 connected to the work platform 20 is able to move the work platform 20 in a direction perpendicular (up and down) to the planar surface 20’, while the moving device 41 connected to the dispensing head 18 displaces the dispensing head 18 in a plane parallel to (horizontally) the planar surface 20’. In this way the 3-dimensional movement of the dispensing head 18 and the work platform 20 relative to each other is created as the resultant of the movements provided by the two moving devices 41 , 42.

As mentioned previously the laser source 30 is configured in such a way that the focus point of the laser beam 31 produced substantially falls on the end 16’ of the metal wire 16 currently being used for the printing of the 3-dimensional metal object 100. This may be implemented with the fixed arrangement of the laser source 30 and the dispensing head 18 relative to each other, as it may be seen in figure 1 a, for example. In this case, by moving the dispensing head 18, both the laser source 30 and its focus point move. In the case of another possible embodiment, the laser source 30 contains a third moving device 43 for changing the direction of the laser beam 31 , with which the movement of the end 16’ of the metal wire 16 can be tracked by the focus point of the laser beam 31 . The moving device 43 preferably contains one or more actuators, and, optionally, one or more mirrors, such as a galvo scanner commonly used for deflecting laser beams, and is also created to be controlled remotely.

It should be noted that the dispensing head 18 and of the moving devices 41 , 42, 43 are preferably controlled by a computer (not shown in the figures), configured to handle the file formats commonly used in 3-dimensional printing (e.g. STL, VRML), as is obvious for a person skilled in the art.

In the case of a particularly preferred embodiment, the apparatus 10 has a cooling-heating module 22 for regulating the temperature of the work platform 20. In the context of the present invention cooling-heating module 22 is understood to mean a device that is capable of raising or lowering the temperature of the work platform 20 by heat conduction. In the case of a possible embodiment, the cooling heating module 22 is configured as a thermoelectric Peltier element. Depending on the direction of the direct current passing through it, the Peltier element heats up or cools down, as is known to a person skilled in the art. It is, of course, also possible to use a cooling-heating module 22 operating on a different principle, for example in which a cooled or heated liquid is circulated in the cooling-heating module 22, for example.

In the case of a preferred embodiment, the apparatus 10 contains an electromagnetic moving means 50 that has a first position connecting the cooling heating module 22 to the work platform 20, and a second position taking the cooling heating module 22 away from the work platform 22. An exemplary embodiment of the moving means 50 may be seen in figure 3. The moving means 50 contains one or more spring pieces 52 separating the work platform 20 from the cooling-heating module 22, and one or more electromagnets 51 . In the case the one or more electromagnets 51 are in switched off state, in other words when the moving means 50 is in its second position, the one or more spring pieces 52 push the cooling heating module 22 away from the work platform 20, thereby preventing their direct contact (see figure 3). By switching on the one or more electromagnets 51 , in other words with the moving means 50 in its first position, an attractive force is created between the electromagnets 51 , which pushes the spring pieces 52 together, through this the work platform 20 and the cooling-heating module 22 come into contact with each other, and in this way heat exchange can start between them. The advantage of the moving means 50 is that the exchange of heat between the work platform 20 and the cooling-heating module 22 can be terminated very quickly, which may be required because of the finite thermal inertia of the cooling-heating module 22.

In the case of a possible embodiment of the apparatus 10 according to the invention, the apparatus 10 contains a vacuum pump 45 for evacuating the work space 12 of the apparatus 10. The vacuum pump 14 may be any known commercially available vacuum pump 14, as is known to a person skilled in the art.

The object of the invention also relates to a method for producing a 3- dimensional metal object 100, particularly a 3-dimensional solid metal object 100. In the following the operation of the apparatus 10 is disclosed along with a presentation of the method according to the invention.

During the method according to the invention, the metal object 100 is produced according to the following in a vacuum using one or more metal wires 16 with different material qualities and having ends 16’.

In the first step of the method, a sealed work space 12 enclosing the work platform 20 is provided. In the case of a preferred embodiment, this takes place with the apparatus 10 according to the invention. The end 16’ of the one or more metal wires 16, optionally with different material qualities, required to form the metal object 100 is then inserted into the work space 12. The insertion of the one or more metal wires 16 preferably takes place manually through the manipulation opening 13. The metal wire 16, in the form of a reel, for example, is inserted into the dispensing head 18, then the manipulation opening 13 is closed. In a particularly preferred embodiment, the dispensing head 18 is configured to feed a plurality of metal wires 16 of different material quality. The ends 16’ of the metal wires 16 may be, for example, arranged next to one another, as is shown in figure 2.

In the next step of the method, a vacuum is created in the work space 12 with the operation of the aforementioned vacuum pump 45, for example, in other words the air is substantially removed from the work space 12. In order to start the printing of the metal object 100, the end 16’ of the metal wire 16 to be used is positioned above the work platform 20, above its planar surface 20’ to be precise, using the moving devices 41 and/or 42. It should be noted that placing above includes the case when the end 16’ comes into contact with the planar surface 20’ of the work platform 20. After the end 16’ is set into the appropriate position, the end 16’ of the metal wire 16 is melted in the work space 12 with the laser beam 31 , thereby producing a molten metal unit 17. The metal wire 16 is pushed forwards with a portion corresponding to size of the molten metal unit 17. The end 16’ is understood to mean the unmelted solid end of the metal wire 16. It should be noted that the melted molten metal unit 17 may be physically break off (become separated from) the metal wire 16 during printing, such as in the case of switching between the metal wires 16 of different quality.

A 3-dimensional metal object 100 in contact with the work platform 20 is built on the work platform 20 from the continuously solidifying molten metal units 17 by moving the work platform 20 and the end 16’ of the metal wire 16 relative to each other. In other words, the metal object 100 is created from the molten metal units 17. Preferably, during the printing of the metal object 10, after the molten metal unit 17 is melted the end 16’ is moved, and the solid end 16’ of the metal wire 16 is melted again with the laser beam 31 so that the next separating molten metal unit 17 solidifies on coming into contact with the previously separating, not yet solidified molten metal unit 17. In this way the metal object 100 is built substantially continuously. During the printing of the metal object 100, if the 3-dimensional metal object 100 is created using several different metals or metal alloys, the metal wires 16 of various material quality are changed by the dispensing head 18 to correspond with the structure of the metal object 100. In other words, for example, a part of the metal object 100 is printed using a metal wire 16 made of steel, then after the part is completed it is replaced with a metal wire 1 6 made of copper, then the rest of the metal object 100 is printed using this metal wire 16.

With the use of the metal wire 16, as opposed to metal powder, no waste is produced, in other words the melted part of the metal wire 16 is substantially completely built into the metal object 100. It was recognised that by printing the metal object 100 in a vacuum, the same melting performance can be achieved with the use of a smaller output laser, or faster printing or the use of a metal wire 16 with a larger diameter becomes possible with a laser of the same output. Therefore, this may result in a saving of time and money. On the other hand, by using a vacuum it is also possible to print a metal object 100 that contains metals or metal alloys that cannot be alloyed to each other at atmospheric pressure.

In the case of a particularly preferred embodiment of the method according to the invention, during the building of the 3-dimensional metal object 100, the temperature of the semi-finished, in other words as yet unfinished metal object 100 in contact with the work platform 20 is maintained at the highest possible temperature by regulating the temperature of the work platform 20 in such a way that the temperature of the semi-finished metal object 100 does not exceed the annealing temperature of the semi-finished metal object 100 at a given point substantially anywhere (in other words with the exception of the immediate vicinity of the melted molten metal unit 17). Annealing temperature is understood to mean that material-quality-dependent temperature above which the metal alloy gradually changes from the non-balanced state (from a hardened or partially hardened state) to the balanced state as time progresses, in other words its hardness drops, its malleability increases, loses brittleness, etc., as is known to a person skilled in the art. This process is known as annealing in metallurgy, which generally is not a desirable phenomenon, as it substantially degrades the material structure properties of the metal object 100. The annealing temperature in the case of steel, for example, is 400 to 650 Celsius degrees depending on the type of steel.

In the case of a preferred embodiment the temperature of the work platform 20 is regulated using the cooling-heating module 22. Before printing the metal object 100, the work platform 20 is heated to a temperature close to but not exceeding the annealing temperature of the material of the metal wire 16 to be used for starting the printing. Due to this, a smaller laser output is sufficient during printing to melt the end 16’ of the metal wire 16 used, furthermore a metal object 100 with more homogenous properties can be created, as optimal temperature conditions are ensured from the start of the printing. As mentioned earlier, the work platform 20 is able to conduct heat to or away from the metal object 100 through the planar surface 20’. If during the printing of the semi-finished metal object 100 a different quality of metal wire 16 needs to be used which has a lower annealing temperature than that of the previously used metal wire 16, the temperature of the work platform 20 (and so of the metal object 100) is correspondingly reduced. It should be noted that during the printing of the metal object 100 the temperature in the vicinity of the melted end 16’, in other words in the immediate vicinity of the melted molten metal unit 17, in all cases exceeds the annealing temperature of the material of the metal wire 16, as in the case of a given material the melting point is always higher than the annealing temperature. As, generally, this area is negligibly small as compared to the dimensions of the metal object 100, and that the annealing process takes time, during which the area in question has time to cool down to under the annealing temperature, this does not cause any problems in practice.

It was recognised that in the vacuum the heat transferred by the laser beam 31 , in the lack of a contact medium, is unable to appropriately dissipate, which leads to the continuous increase of the temperature of the metal object 100. Therefore, in the case of a particularly preferred embodiment while building the 3-dimensional object 100 a part of the heat energy transferred from the laser beam 31 to the semi finished metal object 100 is conducted away through the work platform 20 by cooling the work platform 20 in such a way that the temperature of the semi-finished metal object 100 in contact with the work platform nowhere exceeds the annealing temperature of the semi-finished metal object 100 at any given point with the exception of the immediate vicinity of the melted molten metal unit 17. In other words at the start of the printing of the metal object 100, in order to improve the printing efficiency, heat is transferred to the semi-finished metal object 100 by heating the work platform 20. The heat energy transmitted to the metal object 100 by the work platform 20 and the laser beam 31 continuously increases the temperature of the metal object 100, as the input heat energy is unable to appropriately dissipate due to the lack of a contact medium. Therefore, before the temperature in the semi- finished metal object 100 reaches the annealing temperature of the material at any given point, the superfluous heat energy is conducted away by cooling the work platform 20 with consideration to the size and material composition of the semi finished metal object 100. In this way it can be ensured that no part of the metal object 100 becomes annealed.

Various modification to the above disclosed embodiment will be apparent to a person skilled in the art without departing from the scope of protection determined by the attached claims.

Claims

1 . Method for producing a 3-dimensional metal object (100), particularly a 3-dimensional solid metal object (100), characterised by producing the metal object (100) in a vacuum using one or more metal wires (16) of different material quality that have an end (16’) by:

- providing a sealed work space (12) enclosing a work platform (20),

- inserting the end (16’) of the one or more metal wires (16) into the work space (12),

- producing a vacuum in the work space (12),

- placing the end (16’) of the metal wire (16) above the work platform (20),

- melting the end (16’) of the metal wire (16) in the work space (12) with a laser beam (31 ) to create a molten metal unit (17), and

- on the work platform (20) building a 3-dimensional metal object (100) in contact with the work platform (20) from the continuously solidifying molten metal units (17) by moving the work platform (20) and the end (16’) of the metal wire (16) relative to one another.

2. Method according to claim 1 , characterised by maintaining the temperature of the semi-finished metal object (100) in contact with the work platform (20) at the highest possible temperature during the building of the 3-dimensional metal object (100) by regulating the temperature of the work platform (20) in such a way that the temperature of the semi-finished metal object (100) nowhere exceeds the annealing temperature of a given point on the semi-finished object (100) except for the immediate vicinity of the molten metal unit (17) melted by the laser beam (31 ).

3. Method according to claim 1 or 2, characterised by conducting a part of the heat energy transferred to the semi-finished metal object (100) by the laser beam (31 ) during the building of the 3-dimensional metal object (100) through the work platform (20) by cooling the work platform (20) in such a way that the temperature of the semi-finished metal object (100) in contact with the work platform (20) nowhere exceeds the annealing temperature of a given point on the semi- finished object (100) except for the immediate vicinity of the molten metal unit (17) melted by the laser beam (31 ).

4. Apparatus (10) particularly for the implementation of the method according to claims 1 to 3, characterised by that it contains a vacuum chamber (14) delimiting a sealed work space (12), in which vacuum chamber (14) a dispensing head (18) for feeding one or more metal wires (16) and a work platform (20) are arranged in a spatially movable manner relative to each other, which apparatus (10) contains a laser source (30) for producing a laser beam (31 ) adapted for melting the end (16’) of the metal wire (16) in the work space (12).

5. Apparatus (10) according to claim 4, characterised by that it has a cooling-heating module (22) adapted for regulating the temperature of the work platform (20).

6. Apparatus (10) according to claim 4 or 5, characterised by that the laser source (30) is arranged outside of the vacuum chamber (14), and the vacuum chamber (14) is provided with a window (15) transmitting the laser beam (31 ) emitted by the laser source (30) and ensuring the penetration of the laser beam (31 ) into the sealed work space (12).

7. Apparatus (10) according to claim 4 or 5, characterised by that the laser source (30) is arranged in the vacuum chamber (14).

8. Apparatus (10) according to any of claims 4 to 7, characterised by that it contains a first moving device (41 ) connected to the dispensing head (18) adapted for moving the dispensing head (18) relative to the work platform (20), preferably in 3-dimensional space.

9. Apparatus (10) according to any of claims 4 to 8, characterised by that it contains a second moving device (42) connected to the work platform (20) adapted for moving the work platform (20) relative to the dispensing head (18), preferably in 3-dimensional space.

10. Apparatus (10) according to any of claims 5 to 9, characterised by that the cooling-heating module (22) is formed as a thermoelectric Peltier element.

1 1. Apparatus (10) according to any of claims 5 to 10, characterised by that it contains an electromagnetic moving means (50) that has a first position connecting the cooling-heating module (22) to the work platform (20), and a second position taking the cooling-heating module (22) away from the work platform (20).

12. Apparatus (10) according to any of claims 4 to 1 1 , characterised by that it contains a vacuum pump (45) for evacuating the vacuum chamber (14).