阅读说明：本技术 用于生产含金属物体的增材制造方法 (Additive manufacturing method for producing metal-containing objects ) 是由 布鲁诺·阿尔维斯 罗伯特·克伦普 于 2019-08-22 设计创作，主要内容包括：本发明涉及一种用于生产含金属物体的增材制造方法。根据本发明,增材制造方法至少包括以下步骤：提供(54)含有液体的金属物质混合物,将预定量的含有液体的金属物质混合物施加(56)到抽空的处理空间(12)内的水平衬垫(14、16)上,等待(58)所施加的含有液体的金属物质混合物的液体组分蒸发的等待时间,通过激光束至少部分地熔化(60)所施加的金属物质混合物的金属组分,并重复这些步骤,直到完成要生产的物体(16)。(The present invention relates to an additive manufacturing method for producing a metal-containing object. According to the invention, the additive manufacturing method comprises at least the following steps: providing (54) a liquid-containing metal species mixture, applying (56) a predetermined amount of the liquid-containing metal species mixture onto a horizontal liner (14, 16) within an evacuated processing space (12), waiting (58) for a waiting time for a liquid component of the applied liquid-containing metal species mixture to evaporate, at least partially melting (60) the metal component of the applied metal species mixture by a laser beam, and repeating these steps until the object (16) to be produced is completed.)

1. Additive manufacturing method for producing a metal-containing object (16),

it is characterized in that the preparation method is characterized in that,

at least comprises the following steps:

-providing (54) a liquid-containing mixture of metal species in a feed vessel (18);

-applying (56) a predetermined amount of said liquid-containing metal species mixture onto said pad (14, 16) within the evacuated treatment space (12) in a manner corresponding to the desired geometry by temporarily creating a fluid connection between at least one controllable outlet opening of said feed vessel (18) arranged above the horizontal pad (14, 16) and the treatment space (12);

-waiting (58) for a waiting time for the evaporation of the liquid component of the applied liquid-containing metal substance mixture;

-at least partially melting (60) the metallic component of the applied mixture of metallic substances by means of a laser beam along at least one predetermined path; and

-repeating these steps until the object (16) to be produced is completed.

2. The manufacturing method according to claim 1, wherein the substrate is a glass substrate,

it is characterized in that the preparation method is characterized in that,

the step (56) of applying the liquid-containing metal species mixture is preceded by the following additional steps:

-purging (50) the process space (12) with an inert gas; and

-evacuating (52) the process space (12) to a pressure of less than 100Pa until the gas located in the process space (12) mainly comprises the inert gas.

3. The manufacturing method according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the step of providing the liquid-containing metal species mixture (54) includes using water as the primary liquid component of the liquid-containing metal species mixture.

4. Method of manufacturing according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

comprising the following additional steps:

-assisting the evaporation of the liquid component of the liquid-containing metal species mixture by irradiation with a further laser beam, the optical wavelength of the laser beam being selected in dependence on the maximum absorption of the liquid part of the liquid-containing metal species mixture.

5. Method of manufacturing according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the step of applying (56) the liquid-containing metal species mixture includes using a print head or nozzle tip (20).

6. Method of manufacturing according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the step (56) of applying the liquid-containing metal species mixture includes using a doctor blade.

7. 3D printing device (10) for producing a metal-containing object (16) by a manufacturing method, in particular according to one of the preceding claims, comprising:

-a process space (12) capable of maintaining a vacuum, wherein a horizontal carrier plate (14) is arranged in the process space (12);

-at least one feed container (18) for providing a liquid-containing mixture of metal substances, having at least one controllable outlet opening for alternately establishing and blocking a fluid connection between the feed container (18) and the treatment space (12);

-at least one laser (22) having laser generating means and beam directing means for generating a directable laser beam; and

-an electronic control unit (24) for controlling at least the controllable exit opening, the laser generating means of the laser (22) and the beam directing means.

8. The 3D printing device (10) according to claim 7,

it is characterized in that the preparation method is characterized in that,

the at least one controllable outlet opening of the feed container (18) is formed as a print head or nozzle head (20) capable of withstanding dispersion or suspension pressures or in fluid connection with one of these.

9. The 3D printing device (10) according to claim 7 or 8,

it is characterized in that the preparation method is characterized in that,

further comprising:

a diffuser device disposed in the process space (12), the diffuser device comprising at least one scraper.

10. The 3D printing device (10) according to any of claims 7 to 9,

it is characterized in that the preparation method is characterized in that,

further comprising:

an additional laser having laser generating means and beam directing means for generating a directable laser beam, the optical wavelength of the laser beam being selected based on the maximum absorption of the liquid component of the liquid-containing metal species mixture.

Technical Field

The present invention relates to an additive manufacturing method for producing a metal-containing object according to the preamble of claim 1. The invention also relates to a 3D printing apparatus for producing a metal containing object according to the preamble of claim 7.

Background

Disclosure of Invention

An object of the present invention is to provide a 3D printer for a metal material having a simple structure for performing a 3D printing process by which productivity of an object of the metal material can be improved.

According to the invention, this object is achieved by an additive manufacturing method for producing a metal-containing object having the features of claim 1. The object is also achieved by a 3D printing apparatus for producing a metal-containing object according to claim 7. Furthermore, the respective dependent claims disclose particularly advantageous refinements of the invention.

It should be pointed out that the features and measures presented individually in the following description can be combined with one another in any desired, technically meaningful way and represent further refinements of the invention. Additional features of the invention will be described and illustrated with particular reference to the accompanying drawings.

The additive manufacturing method according to the invention for producing a metal-containing object is characterized in that it comprises at least the following steps:

-providing a liquid-containing mixture of metal species in a feed vessel;

-applying a predetermined amount of a liquid-containing metal species mixture onto a horizontal liner in an evacuated process space in a manner corresponding to a desired geometry by temporarily creating a fluid connection between at least one controllable outlet opening of a feed vessel arranged above the liner and the process space;

-waiting for a waiting time for the evaporation of the liquid component of the applied liquid-containing metal substance mixture; and

-at least partially melting the metal component of the applied mixture of metal substances by means of a laser beam along at least one predetermined path; and

-repeating these steps until the object to be produced is completed.

The method according to the invention combines a number of advantages. On the one hand, compared to the prior art, heating devices for drying the applied metal substance mixture can be dispensed with. On the other hand, in the step of applying the liquid-containing metal species mixture, the pressure generating device can be dispensed with, since this step can be controlled by the positive pressure difference existing in any case between the pressure in the feed vessel and the pressure in the evacuated process space. By omitting these components, a compact production device for carrying out the process can be achieved, which can also be produced with a smaller number of components.

It is considered to be a further advantage that by evaporating the liquid component of the liquid-containing metal substance mixture, particularly effective cooling can be achieved at the location of the product body to be produced, so that a higher production rate can be achieved.

Furthermore, the use of the liquid-containing metal substance mixture can avoid the operator from coming into contact with potentially harmful metal powders used in conventional methods, whereby the work safety can be improved.

The liquid-containing metal substance mixture can be formed as a suspension (particle size typically between 1 μm and 100 μm) or as a dispersion (particle size less than 1 μm), depending on the particle size of the metal components in the substance mixture.

The horizontal gasket can be formed by a carrier plate or a layer already produced by the object to be produced.

At least partial melting of the metal component of the liquid-containing metal species mixture can be carried out, for example, by sintering at a relatively low laser energy or by Selective Laser Melting (SLM) at a relatively high laser energy.

In a preferred embodiment, the manufacturing method comprises the following additional step, performed once before the step of applying the liquid-containing metal species mixture:

-purging the process space with an inert gas; and

-evacuating the treatment space to a pressure of less than 100Pa, preferably 20Pa,

until the gas located in the process space comprises mainly inert gas.

The term "predominantly" means in the context of the present invention in particular that the proportion of substances is greater than 50%, preferably greater than 70%, particularly preferably greater than 90%. In particular, the term is intended to include the possibility that the gas consists entirely of inert gas, i.e. 100%.

The inert gas is effective to prevent potential oxidation of the metal component of the liquid-containing metal species mixture.

The inert gas can be, for example, argon, nitrogen, one or more noble gases or mixtures of these gases.

The step of providing a liquid-containing metal species mixture preferably includes using water as the primary liquid component of the liquid-containing metal species mixture. As a result, existing safety requirements, for example with regard to flammability and/or explosion protection, can be met more easily. Further, when water is mainly used, the above-described cooling effect due to the evaporation of the liquid component of the liquid-containing metal substance mixture is particularly remarkable because the large evaporation heat thereof is 2257 kJ/kg.

In a preferred embodiment, the manufacturing method comprises the following additional steps:

assisting the evaporation of the liquid component of the liquid-containing metal species mixture by irradiation with a further laser beam, the optical wavelength of the laser beam being selected in dependence on the maximum absorption of the liquid part of the liquid-containing metal species mixture.

In this way, the waiting time that must wait until the liquid component of the liquid-containing metal substance mixture evaporates can be shortened, and thus the entire manufacturing process can be accelerated.

Preferably, the step of applying the liquid-containing metal substance mixture comprises using a print head or nozzle head. In this way, by appropriate choice of the print head or nozzle head, the liquid-containing metal substance mixture can be applied in a particularly homogeneous manner on the horizontal pad.

A particularly homogeneous application of the liquid-containing metal substance mixture can be achieved in a similar manner if the application step comprises the use of a doctor blade.

In another aspect of the invention, a 3D printing device for producing a metal-containing object according to the manufacturing method of the invention is presented. The 3D printing device includes:

-a process space capable of maintaining a vacuum, wherein a horizontal carrier plate is arranged in the process space;

-at least one feed vessel for providing a liquid-containing mixture of metal species, having at least one controllable outlet opening for alternately establishing and blocking a fluid connection between the feed vessel and the treatment space;

at least one laser having laser generating means and beam directing means for generating a directable laser beam; and

an electronic control unit for controlling at least the controllable exit opening, the laser generating means of the laser and the beam directing means.

The term "used" means in the context of the present invention specifically programmed, designed or arranged for.

The manufacturing method according to the invention for producing a metal-containing object can be carried out in an advantageous manner by means of the proposed 3D printing device. The advantages mentioned in connection with the manufacturing method according to the invention can be transferred completely to the proposed 3D printing device.

In a preferred embodiment of the 3D printing apparatus, the at least one controllable outlet opening of the feed container is formed as a print head or a nozzle head capable of withstanding a dispersion pressure or a suspension pressure, or is in fluid connection with one of these. As a result, design freedom with respect to the arrangement of the at least one controllable outlet opening with respect to the feed container can advantageously be achieved.

Preferably, the 3D printing device comprises a spreading device arranged in the treatment space, which spreading device comprises at least one doctor blade with which a predetermined amount of the liquid-containing metal substance mixture can be spread particularly uniformly onto the horizontal carrier plate, whereby tight tolerances in the production of the object can be achieved.

In a preferred embodiment, the 3D printing device is equipped with an additional laser having laser generating means and beam directing means for generating a directable laser beam, the optical wavelength of the laser beam being selected in dependence on the maximum absorption of the liquid component of the liquid-containing metal substance mixture. As a result, evaporation of the liquid component of the liquid-containing metal species mixture can be assisted, and thus production of the metal-containing object can be accelerated.

Drawings

Further advantageous developments of the invention are disclosed in the dependent claims and the following description of the drawings, in which:

fig. 1 shows a schematic view of a 3D printing apparatus according to the present invention; and

FIG. 2 shows a flow chart of a method for producing a metal-containing object according to the invention.

Detailed Description

In the various figures, identical components have the same name throughout, so that they are also generally described only once.

Fig. 1 shows a schematic view of a possible embodiment of a 3D printing apparatus for producing a metal containing object according to the invention.

The 3D printing apparatus 10 comprises a processing space 12, the processing space 12 being capable of maintaining a vacuum, having a substantially cubic shape and being fixed in a frame structure 44. The front side of the processing space 12 is formed as a hinged door with a glass window to allow access and viewing of the processing space 12. The hinged door may be locked by a bolt connection. In this state, the elastic sealing element is arranged in a manner known per se between the hinged door and the end face of the treatment space 12.

The treatment space 12 has a plurality of lead- throughs 32, 40, 42 arranged on the walls of the treatment space 12. The first leadthrough 32 in the side wall delimiting the treatment space 12 continues on the outside with a first duct 34. With the first conduit 34, a fluid connection can be established between the process space 12 and the vacuum pump 46. Between the process space 12 and the vacuum pump 46, between portions of the first conduit 34, a valve arrangement 36 is provided, for example comprising an 3/2-way valve, with which 3/2-way valve a fluid connection between the process space 12 and the vacuum pump 46 can be selectively established or blocked, or a fluid connection can be established with the space 38 outside the process space 12 to allow air to enter the process space 12.

The second introduction piece 40 is disposed in a ceiling defining the processing space 12 and continues at an outer side with a second duct. By means of the second conduit, a fluid connection can be established with a storage container 28 for receiving liquid arranged above the treatment space 12, which fluid connection is led to the underside of the storage container 28. The storage vessel 28 is used to store a liquid-containing mixture of metal species for use in producing the metal-bearing object 16 at a pressure substantially corresponding to atmospheric pressure. In this embodiment the solid component of the liquid containing metal substance mixture consists of a hypereutectic aluminium silicon alloy consisting of a powder with an average particle size of about 20 μm and the liquid component of the liquid containing metal substance mixture consists of water.

The third leadthrough 42 is likewise arranged in the ceiling defining the treatment space 12 and continues on the outside with a third duct. By means of a third conduit, a fluid connection can be established with a pressure storage vessel 30 arranged above the process space 12 for receiving gas. The pressure storage vessel 30 is used to store an inert gas, which for example comprises mainly a mixture of nitrogen and argon.

The terms "first", "second", and the like, as used herein, are for distinguishing purposes only. In particular, its use is not meant to imply any order or priority to the objects referenced with these terms.

In the treatment space 12 of the 3D printing device 10, a horizontal, planar carrier plate 14 is fixedly arranged, which serves to mechanically support an object 16 to be produced.

Arranged above the carrying floor 14 in the treatment space 12 is a feed container 18 which can be moved in three spatial directions (up-down, left-right, front-back) perpendicular to one another by an activatable mechanism (not shown). The feed vessel 18 is fluidly connected in a flexible manner to a second intake 40 for receiving and providing a liquid-containing metal species mixture from the storage vessel 28.

The feed vessel 18 has a controllable outlet opening on the underside facing the carrier plate 14, which outlet opening is in fluid connection with a nozzle head 20 capable of withstanding the suspension pressure. The controllable outlet opening is used to alternately establish and block a fluid connection between the feed vessel 18 and the treatment space 12.

The 3D printing device 10 further comprises a laser 22 with laser generating means and beam directing means for generating a directable laser beam. In this particular embodiment, a laser generating device that generates a laser beam is fixedly attached to the feed container 18, and thus, an activatable mechanism can move the feed container 18 and the laser generating device to generate a directable laser beam in three spatial directions that are perpendicular to each other.

In an alternative embodiment, the laser 22 may be fixed, for example, to a ceiling defining the processing space 12, such that the movement of the feed container 18 and the movement of the directable laser beam are independent of each other.

The 3D printing apparatus 10 further comprises an electronic control unit 24 arranged outside the processing space 12 in the frame structure 44. The electronic control unit 24 serves for controlling the controllable outlet opening of the feed container 18, for controlling the laser 22, in particular the laser generating device, and for controlling the dual-function activatable mechanism to move the feed container 18 and as a beam directing device for the laser 22. For this purpose, connection lines are provided between the electronic control unit 24 and the components to be activated, which connection lines are made in a manner known per se from vacuum leads on the bounding walls of the treatment space 12 and, for reasons of overall clarity, are not shown in fig. 1.

The electronic control unit 24 comprises a microcontroller comprising a processor unit having data access rights and a digital data storage unit. For operator control and, for example, input of parameters and display of messages, the electronic control unit has a human-machine interface (HMI) with an input and display unit 26.

One possible embodiment of an additive manufacturing method for producing a metal-containing object 16 by using a 3D printing apparatus 10 according to the invention is described below on the basis of fig. 1 and 2. A flow chart of the method is shown in fig. 2.

The electronic control unit 24 serves for semi-automatic execution of the method and for this purpose comprises a software module for automatically executing the individual steps of the method, the processing steps being executed in the form of executable program code which is stored in a digital data storage unit of a microcontroller of the electronic control unit 24 and which can be executed by a processor unit of the microcontroller of the electronic control unit 24.

In preparation for performing the method, it is assumed that all devices and components involved are in an operational readiness state according to fig. 1.

In preparatory steps 50, 52 of the method, the process space 12 is purged with an inert gas and evacuated 52 by means of a vacuum pump 46 to a pressure of, for example, less than 100Pa, preferably 20Pa, until the gas located in the process space 12 comprises predominantly (e.g. 90%) inert gas.

In a further step 54 of the method, the liquid-containing metal species mixture is provided by gravity at atmospheric pressure from the storage vessel 28 to the feed vessel 18. In a further step 56, a predetermined amount of the liquid-containing metal substance mixture is applied to the horizontal pad in the vacuum processing space 12 in a manner corresponding to the desired geometry. At the beginning of the process, the application takes place on the carrier plate 14 as a horizontal gasket. In the further course of the production of the object 16, the application takes place on an already produced layer of the object 16 to be produced, as a horizontal spacer.

The step 56 of applying the liquid containing metal substance mixture is performed by temporarily establishing a fluid connection between a controllable outlet opening of the feed container 18, which is arranged above the liner, and thus the nozzle head 20 and the process space 12. Due to the pressure difference between the feed vessel 18, which is at atmospheric pressure, and the evacuated process space 12, the liquid-containing metal substance mixture is transported through the nozzle head 20 onto the horizontal liner. The suspension may have a pasty consistency.

Since the process space 12 has been evacuated, the liquid component, e.g. water, is evaporated immediately after the step 56 of applying the liquid-containing metal species mixture. The horizontal mat is effectively cooled at this location due to the large heat of evaporation of water (2257 kJ/kg).

In an alternative embodiment, where the 3D printing device is equipped with a doctor blade, the step of applying the liquid containing metal substance mixture may comprise using a doctor blade.

The next step 58 of the method is waiting for a wait time for the applied liquid component of the liquid-containing metal species mixture to evaporate. The waiting time may be a predetermined, constant waiting time, however, it may also depend in a predetermined manner on the parameters of the applying step 56.

In an alternative embodiment of the 3D printing device comprising an additional laser, the waiting time may be shortened by an additional laser beam for irradiating the applied liquid-containing metal species mixture to assist the evaporation of the liquid component, the optical wavelength of the additional laser being selected based on the maximum absorption of the liquid part of the liquid-containing metal species mixture.

In a further step of the method 60, the remaining metal component of the applied metal substance mixture is partially melted along a predetermined path by the laser beam of the laser 22, thereby forming a connection to the carrier plate 14 or to the already formed layer of the object 16 to be produced.

The steps described, from the step 54 of providing the liquid-containing mixture of metal species to the completion of the object 16 to be produced, are repeatable.

List of reference numerals:

103D printing device

12 processing space

14 carrying plate

16 object

18 feed vessel

20 nozzle tip

22 laser

24 electronic control unit

26 input and display unit

28 storage container (liquid)

30 pressure storage container (gas)

32 first lead-in member

34 first pipeline

36 valve device

38 outer space

40 second lead-in

42 third lead-in member

44 frame structure

46 vacuum pump

The method comprises the following steps:

50 purging the process space with an inert gas

52 evacuating the process space

54 providing a liquid-containing mixture of metal species in a feed vessel

56 applying a predetermined amount of a liquid-containing metal substance mixture on a horizontal pad

58 waiting for the waiting time for the evaporation of the liquid component of the applied liquid-containing metal substance mixture

60 composition of partially molten metal