DE102018214624A1 - Plant for the additive manufacturing of components and method for operating such a plant - Google Patents

Abstract

The invention relates to a system (1) for the additive manufacturing of components using an SLS, SLM or EBM method, comprising at least one closable and heatable construction chamber (2) within which the additive manufacturing can be carried out. In order to reduce the energy consumption of the system (1), the system (1) has at least one device (3) for actively cooling the building chamber (2), the device (3) being set up during the active cooling of the building chamber (2 ) temporarily store the heat absorbed and at least partially return the temporarily stored heat to the building chamber (2) at a later point in time.

Description

The invention relates to a system for additive manufacturing of components using an SLS, SLM or EBM method, comprising at least one closable and heatable building chamber within which the additive manufacturing can be carried out. Furthermore, the invention relates to a method for operating a system for additive manufacturing of components using an SLS, SLM or EBM method, with a closable construction chamber, within which the additive manufacturing is carried out, before and during the implementation of the additive manufacturing heated and cooled after completion of additive manufacturing.

Additive manufacturing (AM) of components is a revolutionary manufacturing technology that has become increasingly important in recent decades. Many components that were previously manufactured in a conventional manner, for example by milling and the like, are now manufactured additively using a 3D printing process. This enables lightweight and ergonomic component designs at a fast manufacturing rate.

Among other additive manufacturing processes, selective laser sintering (SLS), selective laser melting (SLM) and selective electron beam melting (EMB) have become the most relevant manufacturing processes for an industrial environment. With SLS, SLM and EBM, high construction speeds and high quality can be achieved.

However, the current systems for additive manufacturing of components require a large amount of energy for the operation of laser sources or electron beam sources and the heating of a building chamber in which additive manufacturing is carried out. The building chamber is heated to a temperature just below the melting temperature of the powder material to be processed in order to prevent malfunctions. Since a manufacturing process can also take ten hours or longer, the heating of the building chamber must be maintained for a long time, which results in high energy consumption. After completion of the manufacturing process, the building chamber and with it the component located in it must be cooled in order to be able to remove the component from the building chamber.

The CN 205 905 435 U discloses a 3D printer that uses waste heat contained in a process air to heat a material powder.

The publication, which can be downloaded from the link https://shop3duniverse.com/products/3d-print-clean-model-870-enclosure, discloses a construction chamber for a system for additive manufacturing of components.

The KR 101 639 717 B1 discloses a 3D printer using a thermoelectric element. In particular, the 3D printer comprises: a housing with a work space located therein; an extrusion section installed in the housing, extruding and spraying a material; a transfer section for moving the extrusion section in X, Y, and Z axis directions in the work space; a transfer control section that controls the operation of the transfer section; a first thermoelectric element having a first emitting portion that emits heat and a first heat absorbing portion that absorbs the heat and that is installed in the case, so that the first heat emitting portion and the first heat absorbing portion of the outside and the inside of the case, respectively are facing and cools the work space; an element control section that supplies a current to the first thermoelectric element and controls the amperage that is supplied to the thermoelectric element; and a waste heat recovery section that recovers the heat generated in the first thermoelectric element and heats the material and the extrusion section using the recovered heat. The 3D printer can cool the work space and keep it at a constant temperature through the heat absorption portion of the thermoelectric element, and easily extrude the material by heating the material.

The CN 106 541 572 A discloses a 3D printer nozzle cooling device having a stationary station, a cooling water pipe and a water circulation device. A nozzle of a 3D printer is arranged vertically and the upper end of the nozzle is attached to the lower surface of the stationary station. The cooling water pipe is wound around the outer surface of the nozzle in the vertical direction. The water circulation device is arranged at the stationary station. A water inlet end and a water outlet end of the cooling water pipe are connected to the water circulation device.

The CN 106 738 882 A discloses energy-saving 3D printing equipment. The energy-saving 3D printing equipment includes a carrier plate, a connector, a nozzle mechanism, a cooling mechanism, a guide mechanism and a recycling mechanism. The nozzle mechanism has a nozzle and a first heater. The cooling mechanism has heat conduction, a cooling plate and a blower. The The guide mechanism has an air cylinder, a motor and a worm. The recycling mechanism has a recycling box, a second heater, a pump body and a connecting rod. The nozzle mechanism is connected to two guide units so that two materials can be sprayed through one nozzle.

The CN 107 089 006 A discloses a 3D printer with a jacket, an operating platform and a printing platform. Striped rubber cushions are attached to the top edges of the shell, with the fixed portions to which a back plate is attached to wedges by screws are provided with round rubber cushions, resulting in the sound of an upper cover, the back plate and the shell in contact and resonance in the working state can be reduced. The jacket has a three-layer structure and the three layers successively have a protective jacket, a resonance sound absorbing layer and a sound absorption layer from the outside inwards, as a result of which noise of the printer can be further reduced. A coolant is used to cool a high temperature sprayer. A cooling system provided for this purpose has a circulation line which is wrapped vertically around the high-temperature sprayer and a circulation pump at the lower end of the printer.

WO 2017/152133 A1 discloses an apparatus for applying magnetohydrodynamic forces to liquid metal to eject the liquid metal along a controlled pattern, such as a controlled three-dimensional pattern, as part of the additive manufacturing of an object. The magnetohydrodynamic force can be pulsed to eject droplets of the liquid metal to provide control over the accuracy of the object being manufactured. The pulsations can be used in fluid chambers with high resonance frequencies so that droplet ejection can be effectively controlled over a wide frequency range, including high frequencies suitable for ejecting liquid metal at rates suitable for commercially viable three-dimensional fabrication.

The CN 106 583 728 A discloses a 3D printing device with high energy saving performance. The 3D printing device has a printing frame, a control module being arranged on the upper part of the printing frame. Slide rails, which are in sliding connection with slide blocks, are arranged in the middle part of the printing frame. The slide blocks are connected to connecting rods which are connected to a jet nozzle mounting frame. The jet nozzle mounting frame is connected to a jet nozzle, and a blower is arranged on the rear part of the jet nozzle. The jet nozzle mounting frame is connected to a wire guide tube which is connected to a wire feed mechanism. A motor is arranged on the rear part of the wire feed mechanism. A display screen is arranged on the outside of the lower part of the printing frame. A first heating module, the outside of which is provided with a second heating module, is arranged on the lower part of the printing frame. A third heating module, the upper part of which is connected to a plate made of tempered glass, is arranged on the outside of the second heating module. A wire material turntable, which is in sliding connection with a wire material mounting frame, is arranged on the right side of the printing frame.

The invention has for its object to reduce the energy consumption of a system for the additive manufacturing of components.

According to the invention, the object is achieved by a system having the features of claim 1, which has at least one device for actively cooling the building chamber, the device being set up to temporarily store heat absorbed during active cooling of the building chamber and at least the temporarily stored heat at a later time partially returned to the building chamber.

It should be pointed out that the features and measures listed individually in the description below can be combined with one another in any technically expedient manner and indicate further refinements of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figure.

In the system according to the invention, the construction chamber which is closed and heated during the additive production of a component can be actively cooled by means of the device after completion of the additive production, in order to also lower the temperature of the component produced and then be able to remove the component cooled thereby from the construction chamber. In addition, in the system according to the invention, the heat absorbed during the active cooling of the building chamber, that is to say the heat given off by the building chamber and the component therein during active cooling, is temporarily stored by means of the device and is partially or completely fed back to the building chamber at a later time. in order to heat and / or heat them again for carrying out a further additive manufacturing. The heat given off by the building chamber and the component during its cooling does not work as conventionally lost, but is at least partially reused, whereby the energy consumption of the system according to the invention for heating the building chamber, in particular the electrical energy consumption for operating electrical heating devices of the building chamber, is significantly reduced compared to a conventional system. Overall, the system according to the invention thus has a higher efficiency than a conventional system. It can also be provided that the temporarily stored heat is also fed to another device to be heated.

According to an advantageous embodiment, the system has at least one laser unit for performing the SLS or SLM method or an electron beam unit for performing the EBM method, the device being set up to additionally actively cool the laser unit or electron beam unit during active cooling temporarily store the heat absorbed by the laser unit or the electron beam unit and at least partially supply the temporarily stored heat to the building chamber at a later point in time. The laser unit, in particular its laser source, or the electron beam unit usually has to be cooled anyway. This waste heat from the laser unit or the electron beam unit is not lost, as is conventional, but is later partially or completely used to heat the building chamber, as a result of which the energy consumption of the system for heating the building chamber, in particular the electrical energy consumption for operating an electrical heating device of the building chamber, is even more reduced compared to a conventional system.

A further advantageous embodiment provides that the device has at least one heat exchanger arranged at least partially within the construction chamber, at least one heat intermediate store arranged outside the construction chamber, at least one heat exchanger arranged at least partially in the heat intermediate store, at least one fluid circuit connecting the heat exchangers to one another and at least one on the Has fluid circuit arranged pump. When the pump is activated, the device can absorb the heat via the heat exchanger arranged in the building chamber by heating a gaseous or liquid fluid flowing through the heat exchanger. The fluid heated in this heat exchanger flows through the fluid circuit to the heat exchanger arranged in the intermediate heat store and flows through it, as a result of which the heat exchanger is heated and releases the absorbed heat directly to a heat storage medium located in the intermediate heat store. As a result, the fluid in the heat exchanger arranged in the intermediate heat store is cooled again and flows through the fluid circuit back to the heat exchanger arranged in the building chamber in order to absorb heat again. The intermediate heat store can be a store for sensitive heat, a latent heat store or a thermochemical heat store.

According to a further advantageous embodiment, the device has at least one additional heat exchanger arranged on the laser unit or the electron beam unit, at least one additional heat exchanger arranged at least partially in the intermediate heat store, at least one additional fluid circuit connecting the additional heat exchangers and at least one additional pump arranged on the additional fluid circuit. When the additional pump is activated, the device can absorb the heat via the additional heat exchanger arranged on the laser unit or the electron beam unit by heating a gaseous or liquid fluid flowing through the additional heat exchanger. The fluid heated in this additional heat exchanger flows through the additional fluid circuit to the additional heat exchanger arranged in the intermediate heat store and flows through it, as a result of which the additional heat exchanger is heated and releases the absorbed heat directly to a heat storage medium located in the intermediate heat store. As a result, the fluid is cooled again in the additional heat exchanger arranged in the intermediate heat store and flows through the fluid circuit again to the additional heat exchanger arranged on the laser unit or the electron beam unit in order to absorb heat again. Alternatively, the additional fluid circuit and the fluid circuit can be connected to one another, so that the additional heat exchanger arranged in the intermediate heat store can possibly be dispensed with. In addition, the additional pump may then also be dispensed with. The additional fluid circuit can, for example, be connected to the fluid circuit via at least one switching valve, in order to selectively fluid only through the additional heat exchanger arranged on the laser unit or the electron beam unit, only through the additional heat exchanger arranged in the construction chamber or together through the additional heat exchanger on the laser unit or Lead electron beam unit and through the heat exchanger in the building chamber. In addition, provision can be made for the fluid from the additional heat exchanger on the laser unit or the electron beam unit to be applied directly to the heat exchanger arranged in the building chamber in order to partially heat the building chamber with the waste heat from the laser unit or the electron beam unit, if necessary.

According to a further advantageous embodiment, the device has at least one Heat exchangers arranged at least partially within the construction chamber, at least one hot fluid container connected to the heat exchanger, arranged outside the construction chamber, at least one cold fluid container connected to the heat exchanger and arranged outside the construction chamber and at least one on a fluid line between the cold fluid container and the heat exchanger or on a fluid line between the pump arranged on the heat exchanger and the hot fluid container. When the pump is activated, the device can absorb the heat via the heat exchanger arranged in the building chamber by heating a gaseous or liquid fluid originating from the cold fluid container and flowing through the heat exchanger. The fluid heated in this heat exchanger flows through the fluid line to the hot fluid container and is temporarily stored there. When the pumping direction is reversed, the heated fluid is pumped out of the hot fluid container and thus flows through the heat exchanger in the building chamber, where it gives off heat to the building chamber and is thereby cooled. The cooled fluid then flows further into the cold fluid container and is temporarily stored there for the next use.

A further advantageous embodiment provides that the device has at least one additional heat exchanger arranged on the laser unit or the electron beam unit, which is connected on the one hand to the cold fluid container and on the other hand directly or indirectly via the construction chamber to the warm fluid container, and at least one on a fluid line between the Cold fluid container and the additional heat exchanger or on the other hand arranged on a fluid line between the additional heat exchanger and the warm fluid container or on a fluid line between the building chamber and the warm fluid container auxiliary pump. When the additional pump is activated, the device can absorb the heat via the additional heat exchanger arranged on the laser unit or the electron beam unit by heating a gaseous or liquid fluid originating from the cold fluid container and flowing through the additional heat exchanger. The fluid heated in this additional heat exchanger flows through the fluid line to the hot fluid container and is temporarily stored there.

According to a further advantageous embodiment, the system has at least one electronic control unit that controls the device. The control electronics can take temperature values into account for controlling the device via at least one temperature sensor in the building chamber and / or on the laser unit or the electron beam unit. The control electronics can also be set up to automatically carry out a manufacturing process, including heating, heating and active cooling of the building chamber.

The above object is further achieved by a method having the features of claim 8, in which the building chamber is actively cooled after completion of the additive manufacturing, heat absorbed during the active cooling of the building chamber and the temporarily stored heat at least partially at a later time is returned to the building chamber.

The advantages associated with the system above are correspondingly associated with the method. In particular, the system can be used according to one of the above-mentioned configurations or a combination of at least two of these configurations with one another to carry out the method.

According to an advantageous embodiment, a laser unit for carrying out the SLS or SLM method or additionally an electron beam unit for carrying out the EBM method is additionally actively cooled, the heat absorbed during the active cooling of the laser unit or the electron beam unit being temporarily stored and the temporarily stored heat being added is at least partially fed to the building chamber at a later time. With this configuration, the advantages mentioned above with reference to the corresponding configuration of the system are associated accordingly.

A further advantageous embodiment provides that the building chamber is at least partially heated directly with the heat absorbed during the active cooling of the laser unit or the electron beam unit. As a result, the energy consumption for heating the building chamber can be reduced by means of an electrical heater.

• 1 eine schematische Darstellung eines Ausführungsbeispiels für eine erfindungsgemäße Anlage.

Further advantageous embodiments of the invention are disclosed in the subclaims and the following description of the figures. It shows

• 1 is a schematic representation of an embodiment for a system according to the invention.

1 shows a schematic representation of an embodiment for a system according to the invention 1 for additive manufacturing of components, not shown, using an SLS or SLM process. The attachment 1 has a lockable and heated construction chamber 2 on, within which the additive manufacturing can be carried out.

Furthermore, the facility points 1 a device 3 for active cooling of the building chamber 2 on. The contraption 3 is set up during the active cooling of the building chamber 2 temporarily store the heat absorbed and, at a later point in time, at least partially restore the temporarily stored heat to the building chamber 2 feed. For this purpose, the device 3 one inside the building chamber 2 arranged heat exchanger 4 , one with the heat exchanger 4 connected, outside the building chamber 2 arranged hot fluid container 5 , one with the heat exchanger 4 connected, outside the building chamber 2 arranged cold fluid container 6 and one on a fluid line 7 between the cold fluid container 6 and the heat exchanger 4 arranged pump 8th on. Alternatively, the pump 8th on a fluid line 9 between the heat exchanger 4 and the warm fluid container 5 be arranged.

The attachment 1 also has one at the building chamber 2 arranged laser unit 10 to perform the SLS or SLM procedure. The device 3 is set up, in addition the laser unit 10 to actively cool while the laser unit is actively cooling 10 temporarily store the heat absorbed and the temporarily stored heat at least in part later in the building chamber 2 feed. For this purpose, the device 3 one on the laser unit 10 arranged additional heat exchanger 11 on the one hand with the cold fluid container 6 and on the other hand directly with the hot fluid container 5 is connected, and one on a fluid line 12 between the cold fluid container 6 and the additional heat exchanger 11 arranged auxiliary pump 13 on. Alternatively, the additional pump 13 on a fluid line 14 between the additional heat exchanger 11 and the warm fluid container 5 be arranged. Alternatively, the additional heat store 11 about the building chamber 2 indirectly with the warm fluid container 5 be connected by the dashed arrow 15 should be hinted at. In this case, the auxiliary pump 13 alternatively on the fluid line 9 be arranged. If there is already the pump 8th is arranged can on the auxiliary pump 13 to be dispensed with.

Furthermore, the facility 1 a the device 3 controlling control electronics 16 on, at least with the pump 8th and the auxiliary pump 13 connected is.

Reference list

1

investment

2

Building chamber

3

contraption

4

Heat exchanger

5

Hot fluid container

6

Cold fluid container

7

Fluid line

8th

pump

9

Fluid line

10

Laser unit

11

Additional heat exchanger

12th

Fluid line

13

Auxiliary pump

14

Fluid line

15

Arrow (11 connected via 4 to 5)

16

Control electronics

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• CN 205905435 U [0005]
• KR 101639717 B1 [0007]
• CN 106541572 A [0008]
• CN 106738882 A [0009]
• CN 107089006 A [0010]
• CN 106583728 A [0012]

Claims (10)

System (1) for the additive manufacturing of components using an SLS, SLM or EMB method, comprising at least one lockable and heatable building chamber (2) within which the additive manufacturing can be carried out, characterized by at least one device (3) for active cooling of the building chamber (2), the device (3) being set up to temporarily store the heat absorbed during the active cooling of the building chamber (2) and to at least partially return the temporarily stored heat to the building chamber (2) at a later point in time. Appendix (1) to Claim 1 , characterized by at least one laser unit (10) for performing the SLS or SLM method or at least one electron beam unit for performing the EBM method, the device (3) being set up to additionally actively activate the laser unit (10) or the electron beam unit cool, temporarily store heat absorbed during the active cooling of the laser unit (10) or the electron beam unit and at least partially supply the temporarily stored heat to the building chamber (2) at a later point in time. Appendix (1) to Claim 1 or 2 , characterized in that the device (3) at least one heat exchanger (4) arranged at least partially within the construction chamber (2), at least one heat intermediate store arranged outside the construction chamber (2), at least one heat exchanger arranged at least partially in the heat intermediate store, at least one Has heat exchangers connecting fluid circuit and at least one pump arranged on the fluid circuit. System (1) according to one of the preceding claims, characterized in that the device (3) at least one additional heat exchanger (11) arranged on a laser unit (10) or the electron beam unit, at least one additional heat exchanger (11) arranged at least partially in the intermediate heat store, has at least one additional fluid circuit connecting the additional heat exchangers (11) and at least one additional pump arranged on the additional fluid circuit. System (1) according to one of the preceding claims, characterized in that the device (3) at least one heat exchanger (4) arranged at least partially inside the building chamber (2), at least one outside of the building chamber (2) connected to the heat exchanger (4) ) arranged hot fluid container (5), at least one cold fluid container (6) connected to the heat exchanger (4), arranged outside the construction chamber (2) and at least one on a fluid line (7) between the cold fluid container (6) and the heat exchanger (4) or has a pump (8) arranged on a fluid line (9) between the heat exchanger (4) and the warm fluid container (5). System (1) according to one of the preceding claims, characterized in that the device (3) at least one additional heat exchanger (11) arranged on a laser unit (10) or the electron beam unit, on the one hand with the cold fluid container (6) and on the other hand directly or via the building chamber (2) is indirectly connected to the hot fluid container (5), and at least one is connected to a fluid line (12) between the cold fluid container (6) and the additional heat exchanger (11) or to a fluid line (14) between the additional heat exchanger (11 ) and the hot fluid container (5) or on the fluid line (9) between the building chamber (2) and the hot fluid container (5) arranged auxiliary pump (13). System (1) according to one of the preceding claims, characterized by at least one control electronics (16) which controls the device (3). Method for operating a system for additive manufacturing of components using an SLS, SLM or EBM method, in particular one of the preceding claims, wherein a closable building chamber (2) within which the additive manufacturing is carried out before and during the implementation the additive manufacturing is heated and cooled after the completion of the additive manufacturing, characterized in that the building chamber (2) is actively cooled after the completion of the additive manufacturing, while the active cooling of the building chamber (2) is temporarily stored and the temporarily stored heat becomes one is later at least partially returned to the building chamber (2). Procedure according to Claim 8 , characterized in that additionally a laser unit (10) for performing the SLS or SLM method or additionally an electron beam unit for performing the EBM method is actively cooled, while the heat absorbed during the active cooling of the laser unit (10) or electron beam unit is temporarily stored and the temporarily stored heat is at least partially supplied to the building chamber (2) at a later point in time. Procedure according to Claim 9 , characterized in that the building chamber (2) at least partially directly with the during the active cooling of the Laser unit (10) or the electron beam heat is heated.

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