DE102019131059A1 - Swap body container and device for additive manufacturing of a workpiece, process station and system for it - Google Patents

Abstract

Known interchangeable containers (70; 300; 400; 504; 505) for the additive manufacturing of a workpiece (104) have a housing (101) which surrounds a construction space (19) with a base area (20) and an outer surface (21), a construction platform (22) which delimits the installation space (19) on the base side, and a heating device (49) with a jacket heater (44) assigned to the jacket surface (21) of the installation space (19). On the basis of this, to specify a swap body in which the starting materials can be pretreated and the workpiece including the remaining starting materials can be post-treated, in which the risk of cracking or warpage of the workpiece - especially during the transport of the swap body - is reduced, it is proposed that Housing (101) has a closable cover (71; 500) and the jacket heater (44) comprises an infrared radiation source and / or a UV radiation source, wherein between the infrared radiation source and / or the UV radiation source on the one hand and the Installation space (19), on the other hand, a partition (28) made of a material that is transparent to infrared radiation and / or UV radiation is arranged.

Description

Technical background

• - ein Gehäuse, das einen Bauraum mit einer Grundfläche und einer Mantelfläche umgibt,
• - eine Bauplattform, die den Bauraum grundflächenseitig begrenzt, und
• - eine Heizeinrichtung mit einer der Mantelfläche des Bauraums zugeordneten Mantel-Heizung.

The invention relates to an interchangeable container for the additive manufacturing of a workpiece, comprising:

• - a housing that surrounds an installation space with a base and a lateral surface,
• - A construction platform that delimits the installation space on the base side, and
• - A heating device with a jacket heater assigned to the jacket surface of the installation space.

The invention also relates to a device for additive manufacturing of a workpiece with a laser beam source or an electron beam source.

The invention also relates to a process station for a workpiece produced with a device for additive manufacturing.

Finally, the invention relates to a system for additive manufacturing and machining of a workpiece.

The term “additive manufacturing” describes a manufacturing process in which a workpiece is manufactured by building up layers. The terms “additive manufacturing”, “3D printing”, “rapid prototyping” or “generative manufacturing” are also used synonymously. The term is used below in such a way that it includes the production of the workpiece by building it up in layers, but not preceding or possibly subsequent process steps, even if these process steps influence the physical and chemical properties of the additively manufactured workpiece. Examples of process steps that are not covered by the concept are a subsequent (high) temperature treatment of the additively manufactured workpiece, subsequent compression of the same by hot isostatic pressing (HIP) or a controlled cooling process.

The workpiece is built up in layers in a "device for additive manufacturing of a workpiece". In order to increase the throughput of this device, pre- and post-processing manufacturing steps can be carried out in a device other than the device for additive manufacturing, i.e. in an “external” station; such a station is referred to below as a “process station”.

A “swap body” in the sense of the invention can be used both in the additive manufacturing of three-dimensional workpieces and in the process steps preceding or following the additive manufacturing. It is designed so that it can be used in a “device for additive manufacturing”, but also in a “process station” because: Additive manufacturing can, for example, be preceded by a pretreatment of the raw materials used for additive manufacturing in a first process station or Additive manufacturing can be followed by post-treatment of the additively manufactured workpiece in a second process station. A simple example of pretreatment is preheating of the raw materials used for additive manufacturing. A simple example of post-treatment is a controlled cooling of the workpiece in the swap body until the workpiece is removed from the installation space. A controlled cooling of the workpiece is used to avoid thermal stresses caused by too rapid cooling, as this can lead to cracks and warpage of the additively manufactured workpiece. The controlled cooling is preferably carried out in an inert atmosphere; however, it can also take place in an oxidizing atmosphere in order to passivate the workpiece and the reusable starting material.

State of the art

Additive manufacturing processes are often used to manufacture three-dimensional molded parts made of plastic, metal or ceramics. The usual processes include the selective laser sintering (SLS, Selective Laser Sintering) of plastic powders or laser beam melting (LBM, Laser Beam Melting; synonymous also: SLM, Selective Laser Melting) of metal powders or ceramic powders, but also the EBM (Electron Beam Melting) of metal powders. With these layer build-up techniques, the workpiece is built up in layers in a powder bed. After a first powder layer has been provided, it is selectively melted using a laser. Unexposed powder remains in the installation space; the layer of selectively melted and loose powder is covered with a further layer of powder and this is then selectively melted. This process is repeated until the workpiece is built up in layers.

After the layer-wise build-up of the workpiece has been completed, it is necessary to allow the installation space with the unconsolidated, loose powder and the additively manufactured workpiece located therein to cool before the loose powder can be removed and the workpiece can be removed from the device. Since a high installation space temperature is often required, particularly in the manufacture of metallic and ceramic workpieces, the cooling process must be slow. This is the only way to be able to Warpage, thermal tension and cracks in the workpiece can be reliably prevented. Defined cooling rates and holding times are often specified. The workpiece remains in the additive manufacturing device during the cooling process.

However, such a procedure has the disadvantage that the device cannot be used for a certain period of time due to the necessary cooling phase.

From the US 2008/0 190 905 A1 a device for additive manufacturing of a workpiece is known which has a construction container with an inner container arranged therein. The inner container is the boundary frame for the powdery starting material; it can be removed from the building container through an opening in the building container. The advantage of this approach is that the workpiece located in the inner container can be cooled outside the additive manufacturing device after the inner container has been removed. Once the inner container and the workpiece have been removed, the additive manufacturing device is immediately available for another additive manufacturing process. Because the inner container itself does not include a heating device, it is possible for the workpiece to cool in an uncontrolled manner during transport to a cooling station, which can lead to cracks or warpage of the workpiece.

Also in the US 2018/0 161 934 A1 it is proposed that additive manufacturing and the controlled cooling of the workpiece be spatially separated until it is removed from the installation space and carried out in different devices. The device described therein has a device for additive manufacturing in a separate housing and a heating station in another housing. The construction chamber with the construction space in it is transported from the device for additive manufacturing to the heating station in an air lock. To prevent the build chamber from cooling down uncontrollably during the transfer, the build chamber is equipped with heating elements in the form of resistance heating elements, quartz lamps or electromagnets.

The one in the US 2018/0 161 934 A1 The heating elements mentioned are designed exclusively for transporting the building chamber to the heating station. The actual heating device, however, is arranged in the heating station. However, this can prove to be disadvantageous if larger installation spaces have to be heated and / or unforeseen time delays during the transport of the construction chamber have to be compensated for. In these cases, temperature differences and temperature inhomogeneities can occur in the building space during transport, for which the heating device of the building chamber is not designed to compensate. The consequence is an increased risk of cracking or distortion of the workpiece. In addition, the temperature deviations in the installation space can also have an effect on other process parameters, which can also promote the formation of cracks or warpage of the workpiece. Examples of this are the occurrence of pressure changes, in particular the process gas pressure in the gas space, or changes in the process gas composition.

Technical task

The present invention is therefore based on the technical problem of specifying a swap body for the additive manufacturing of a workpiece in which the starting materials can be pretreated and the workpiece together with the remaining starting materials can be post-treated, with the risk of cracking or warpage of the workpiece - in particular during the transport of the interchangeable container - is reduced, and which also enables a cost-effective production of an additively manufactured workpiece.

Furthermore, the present invention is based on the object of specifying a corresponding device for additive manufacturing of a workpiece, a corresponding process station and a system for additive manufacturing and machining of a workpiece.

Summary of the invention

With regard to the interchangeable container, this object is achieved according to the invention on the basis of an interchangeable container of the type mentioned at the beginning in that the housing has a closable cover and the jacket heater comprises an infrared radiation source and / or a UV radiation source, with between the infrared radiation source and / or the UV radiation source on the one hand and the installation space on the other hand a partition made of a material transparent to infrared radiation and UV radiation is arranged.

The present invention is based on the idea that the formation of rejects in the production of additively manufactured workpieces can be reduced if the interchangeable container is equipped with a heating device that can be operated with high power and good efficiency. As a result, the heating device of the swap body container can not only be used during transport, but is also suitable for carrying out further heating processes for which a separate process station with its own heating unit would otherwise have been required.

According to the invention, it is therefore provided that the jacket heater comprises an infrared radiation source and / or a UV radiation source. With infrared radiation sources as well as with UV radiation sources, the energy transfer takes place through radiation. This type of energy transfer proves to be advantageous compared to other types of energy transfer such as convection or heat conduction, since it regularly enables the radiation sources to be operated with high power and at the same time has a good degree of efficiency.

With regard to an interchangeable container with an infrared radiation source, it has proven particularly useful if the infrared radiation source has an output based on the length of the heating filament in the range from 20 W / cm to 50 W / cm, particularly preferably in the range from 25 W / cm to 40 W / cm. In these performance ranges, round tube infrared emitters with tungsten filaments typically have filament temperatures of 1,500 ° C to 2,300 ° C. This corresponds to peak wavelengths of around 1.0 µm to 1.4 µm. Heating tests with various metal powders have shown that in particular radiation with peak wavelengths between 1.1 µm and 1.3 µm for efficient heating of most metal powders, in particular metal powders made of iron, aluminum, titanium, nickel, cobalt, tungsten, tantalum, molybdenum, Platinum, rhenium, ruthen, silver, gold, iridium, niobium, magnesium and their alloys, is suitable.

UV radiation sources, on the other hand, prove to be advantageous when heating powders with a powder content of highly reflective metals of 50% by weight or more. Highly reflective metals are, for example, gold, silver, chromium, nickel or copper. However, UV radiation sources prove to be particularly advantageous when heating copper powder or powders containing copper. Copper powder and copper-containing powders reflect radiation incident on them to a high degree. Heat-up tests have shown that a particularly efficient introduction of energy into these powders can be achieved with UV radiation, in particular when the UV radiation has wavelengths in the range from 250 nm to 450 nm.

• Der erfindungsgemäße Wechselbaubehälter muss mit Energie versorgt werden, um die Heizeinrichtung betreiben zu können. Die hierfür notwendige Energie kann zwar grundsätzlich auch durch einen internen Akkumulator bereitgestellt werden. In den meisten Fällen dürfte der Wechselbaubehälter jedoch mit einer externen Stromquelle verbunden sein, insbesondere, wenn er in einer Vorrichtung für die Additive Fertigung eines Werkstücks oder einer Prozessstation eingesetzt ist. Darüber hinaus kann eine Bereitstellung weiterer Medien (z.B. Kühlflüssigkeit, Pulverausgangsmaterial, Prozessgas) erforderlich sein. Im einfachsten Fall erfolgt die Bereitstellung von Medien über Versorgungsleitungen, wie Kabel und Schläuche, die über lösbare Verbindungen, beispielsweise mit Steckern und Schnellkupplungen, mit dem Wechselbaubehälter verbunden werden können. Auf diese Weise kann der Wechselbauchbehälter einfach von der Vorrichtung für die Additive Fertigung gelöst und mit einer Prozessstation verbunden werden. Bei kurzen, schnellen Transportwegen erweist es sich als unproblematisch, wenn der Wechselbaubehälter während des Transportvorgangs nicht mit einer Medienversorgung verbunden ist. Anders ist die Situation aber, wenn für den Transportweg ein gewisser Zeitraum benötigt wird, beispielweise, weil die Vorrichtung für die Additive Fertigung und die Prozessstation räumlich voneinander getrennt erfolgen. Dann kann es notwendig sein, auch während des Transports einige Prozessparameter zu überwachen und gegebenenfalls auftretenden Abweichungen möglichst zeitnah entgegenzusteuern. Hierdurch kann die Entstehung von Ausschuss verringert werden. Zum Beispiel kann die Infrarot-Strahlungsquelle und/oder die UV-Strahlungsquelle während des Transports betrieben werden, um ein zu schnelles Abkühlen des im Wechselbaubehälter befindlichen Werkstücks zu vermeiden. Auch wenn für einen „normalen“ Transportvorgang die erfindungsgemäße Heizeinrichtung gewissermaßen überdimensioniert sein mag, ist es möglich, dass beispielsweise während des Transportvorgangs unerwartete zeitliche Verzögerungen auftreten können, die durch den erfindungsgemäßen Wechselbaubehälter besser kompensierbar sind. Insbesondere aber können auch Heizvorgänge, die ansonsten in der Prozessstation durchgeführt werden müssten, bereits während des Transports begonnen werden. Dies trägt sowohl zu einer Prozessbeschleunigung als auch zu einer verringerten Ausschuss-Entstehung durch Rissbildung und Verzug des Werkstücks bei. Darüber hinaus kann auf eine zusätzliche Heiz-Einheit in der Prozessstation verzichtet werden.

A swap body with such a heating device has several advantages:

• The interchangeable container according to the invention must be supplied with energy in order to be able to operate the heating device. The energy required for this can in principle also be provided by an internal accumulator. In most cases, however, the interchangeable container is likely to be connected to an external power source, especially if it is used in a device for additive manufacturing of a workpiece or in a process station. In addition, it may be necessary to provide additional media (e.g. cooling liquid, powder starting material, process gas). In the simplest case, the supply of media takes place via supply lines, such as cables and hoses, which can be connected to the interchangeable container via detachable connections, for example with plugs and quick-release couplings. In this way, the swap body container can easily be detached from the device for additive manufacturing and connected to a process station. In the case of short, fast transport routes, it turns out to be unproblematic if the swap body is not connected to a media supply during the transport process. The situation is different, however, if a certain period of time is required for the transport route, for example because the device for additive manufacturing and the process station are spatially separated from one another. It may then be necessary to monitor some process parameters during the transport and to counter any deviations as soon as possible. This can reduce the formation of rejects. For example, the infrared radiation source and / or the UV radiation source can be operated during transport in order to prevent the workpiece in the swap body from cooling too quickly. Even if the heating device according to the invention may be oversized, so to speak, for a “normal” transport process, it is possible that unexpected time delays may occur during the transport process, which can be better compensated for by the swap body according to the invention. In particular, however, heating processes that would otherwise have to be carried out in the process station can already be started during transport. This contributes to both accelerating the process and reducing the formation of rejects due to the formation of cracks and distortion of the workpiece. In addition, there is no need for an additional heating unit in the process station.

With additive manufacturing, the installation space is usually filled with powdery starting material. In order to prevent the infrared radiation source or the UV radiation source from coming into contact with the contents of the installation space, according to the invention a partition wall transparent to infrared radiation and UV radiation is arranged between the radiation source and the installation space. Infrared radiation is divided into three bands (IR-A, IR-B, IR-C): IR-A radiation has wavelengths in the range from 0.78 µm to 1.4 µm; the wavelengths of IR-B radiation are in the range of 1, 4 µm to 3.0 µm and that of IR-C radiation in the range from 3 µm to 1000 µm. According to DIN 5031, Part 7, UV radiation covers the wavelength range from 100 nm to 380 nm. The partition is advantageously made of quartz glass or glass ceramic. The partition wall protects the infrared radiation source from contamination; In contrast to the infrared radiation source, it is easy to clean. In addition, the partition makes it easier to repair or replace the radiation source. The particular advantage of a partition made of a material that is transparent to infrared radiation and UV radiation is that it is possible to quickly convert an existing swap body, depending on whether a UV radiation source and / or an infrared is used in additive manufacturing -Radiation source is to be used. This is not only cost-effective, but it should also contribute to the fact that a smaller number of swap bodies must be kept ready. It is also possible to retrofit an existing installation space of an interchangeable container with an infrared radiation source separated by a partition wall in a simple and cost-effective manner.

Because the housing has a closable cover, the starting materials, but also a workpiece located in the installation space, are protected from external influences. The closable seal is preferably gas-tight. Gas tightness is present if the leak rate does not exceed approx. 10 ^-7 mbar * I / s. This can be determined, for example, with a universal sniffer leak search or a helium leak search. The gas tightness is after DIN EN 1330-8: 1998 certainly. In practice, a higher leak rate of 10 ^-6 mbar * I / s may also be accepted. In the simplest case, the closable cover is a lid. This has the advantage that the swap body can easily be loaded with starting material from above. This also makes it easier to remove the workpiece.

The interchangeable container is preferably designed for the additive manufacturing of a workpiece from a powdery starting material. The interchangeable container according to the invention is also particularly suitable for starting materials that can be elastically deformed before they break and are characterized by a high degree of brittleness. Therefore, these materials tear in the tensile test close to the elastic limit with no or only slight plastic deformation. Precious metal alloys, iron-based alloys, eg “Invar, shape memory alloys” can hardly be processed in a conventional device for additive manufacturing of a workpiece with a pure platform heater. Because workpieces manufactured in this way regularly have high internal stresses and tend to crack.

It has proven useful if the powdery starting material comprises an aluminum, a noble metal and / or a refractory metal powder. Precious metals in this sense are gold, platinum, iridium, palladium, osmium, silver, rhodium and ruthenium; Refractory metals are the metals of the 4th, 5th and 6th subgroup. These include titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten. The aluminum, noble metal and / or refractory metal powder or a mixture thereof is advantageously the main component of the powdery starting material.

It has proven to be particularly advantageous if the heating device comprises a platform heater assigned to the building platform.

A swap body container with an additional platform heater offers the advantage that the installation space and its contents can be heated as uniformly as possible. A jacket heater heats the installation space and the parts located in the installation space, such as the workpiece or any remaining powder, only from the side. This can lead to the outer area of the installation space facing the jacket heating being heated to a greater extent than its inner area. A platform heater provided in addition to the jacket heater counteracts this phenomenon.

In a preferred embodiment of the interchangeable container according to the invention, it is provided that the additive manufacturing of the workpiece comprises at least one high-temperature treatment and one low-temperature treatment, and that the heating device is designed in such a way that the high-temperature treatment and the low-temperature treatment can be carried out with it.

When manufacturing additively manufactured workpieces, high-temperature treatments are often carried out in a separate process station that has its own heating unit. By means of the infrared radiation source provided according to the invention, both the high-temperature treatment and the low-temperature treatment can be carried out with the heating device of the interchangeable container. This is possible because infrared radiation sources can be operated regularly with high power and at the same time have a good level of efficiency. As a result, there is no need for an additional heating unit in the process station. Ideally, the heating device of the interchangeable container is designed in such a way that it can be used for all heating processes during additive manufacturing of the workpiece and the subsequent heating processes can also be carried out until the workpiece is removed from the installation space.

It has proven useful if the housing is provided with a cooling device.

The cooling device thermally shields the heating device of the swap body. It primarily contributes to the fact that the thermal stress on a device for additive manufacturing of a workpiece or a process station is kept as low as possible by a removable container inserted therein. With the help of the cooling device, however, heat can also be extracted from the installation space. The cooling effect of the cooling device is not limited to the installation space and its contents: all components of the interchangeable container can also be cooled quickly and reliably with the cooling device before the workpiece and excess starting material are removed from the installation space. This reduces oxidation of the components of the interchangeable container, but also of the starting material, which is usually in powder form. Above all, however, an interchangeable container with a heating device and a cooling device enables heating and cooling processes to be sequenced as desired. This not only shortens the otherwise necessary waiting time, but also improves the efficiency of the processes. In particular, by combining an infrared heating device with a housing that can be cooled with the cooling device, defined heating or cooling ramps and holding times can be implemented quickly and easily. It goes without saying that the provision of a cooling device does not exclude the alternative or parallel implementation of other cooling methods. The swap body can also be equipped with cooling connections via which a fluid medium can be passed through the installation space. A cooling method that uses a fluid medium passed through the installation space for cooling is described, for example, in the publication DE 10 2017 211 381 A1 described. The interchangeable container preferably has cooling connections which are used to carry out the from the DE 10 2017 211 381 A1 known cooling process are designed.

The building platform is advantageously provided with a cooling unit.

A cooling unit assigned to the building platform helps to improve the adjustability of the desired heating and cooling ramps. It also has the advantage that it contributes to an even cooling of the installation space and its contents. Even during a cooling process, the phenomenon already explained above for jacket heating can arise that the outer area of the installation space facing the jacket heating has a different temperature than its inner area. An additional cooling unit assigned to the building platform counteracts this phenomenon.

A uniform temperature distribution within the installation space can also be achieved by setting up an additional "auxiliary structure" in the installation space parallel to the construction of the workpiece. Since the auxiliary structure itself conducts heat, it can be used as a temperature bridge to compensate for temperature differences and to set a uniform installation space temperature. In particular, the auxiliary structure conducts the heat introduced by the jacket and / or platform heating device into the interior of the installation space. But: The auxiliary structure can be used not only as a heating structure, but also as a cooling structure. Such a procedure proves to be particularly advantageous with a large installation space diameter of more than 150 mm. The shape, volume and position of the auxiliary structure can be calculated with a previously performed thermal simulation. In addition, the auxiliary structure can be exposed several times by the laser or electron beam source and, if necessary, provided with cavities as beam traps.

It has proven to be advantageous if the housing has one or more media connections for the supply / discharge of a cooling fluid.

A cooling of the housing or the construction platform with a cooling fluid is easy to implement. In the simplest case, the housing, a mounting plate for the building platform or the building platform itself can be provided with cooling channels. By integrating the cooling channels into an existing component, little additional space is required. Additional installation space is only to be provided for the media connections.

In addition, it has proven to be advantageous if the housing comprises one or more gas connections for the supply or discharge of a process gas.

The raw materials used in additive manufacturing are often sensitive to oxidation. Additional gas connections enable the installation space and the fluidically connected gas space to be charged with a process gas. A process gas in this sense can therefore be, for example, an inert gas that leads to an inert atmosphere; but it can also be a reactive gas, for example a reducing gas. The process gas can be supplied to and removed from the installation space or the gas space via the gas connections, or the installation space and the gas space located above it can be supplied via the Gas connections are evacuated. Several gas connections also enable a particularly homogeneous evacuation, loading or inerting of the gas and / or installation space. In particular, they can be used to generate turbulence in the gas and construction space, which helps to prevent oxygen from remaining or being trapped (so-called “oxygen pockets”) in the starting material.

In a preferred embodiment of the interchangeable container according to the invention, the housing has one or more powder connections for the inert removal of powder from the installation space and / or for the return of powder into the installation space.

From an EHS and QM point of view, an inert atmosphere is usually necessary within the installation space. Once the interchangeable container has cooled down, the powder connections allow powder to be removed from the installation space without affecting the existing gas atmosphere. The workpiece can then be removed in a "normal atmosphere" and the interchangeable container set up again.

In addition, it is also possible to feed further powder into the installation space or into a storage space of the device via the powder connections, without impairing a possibly existing inert gas atmosphere. The advantage of a subsequent supply of additional powder is that the powder supply in the interchangeable container can be small, so that it only requires a small proportion of the volume of the interchangeable container.

The media connections and / or the gas connections and / or the powder connections are advantageously provided with self-sealing quick-release couplings.

In order to be able to install and dismantle the interchangeable container as easily and quickly as possible in a device for additive manufacturing of a workpiece or in a process station, its connections are provided with self-sealing quick-release couplings. In particular, a dismantled interchangeable container can be quickly reconnected to the power, cooling fluid, gas and / or powder supply of a device for additive manufacturing of a workpiece or a process station.

The temperature of the outer surface of the installation space can be measured with pyrometers arranged outside the installation space. The interchangeable container advantageously comprises several temperature sensors with which the temperature distribution in the installation space can be monitored. It has proven to be advantageous here if the multiple temperature sensors are designed in such a way that they can be pushed into the installation space. In addition, it has proven to be particularly advantageous if at least one of the gas connections is connected to a gas sensor with which the atmosphere in the gas and / or construction space of the interchangeable container or the oxygen content therein can be monitored.

In particular, during a transfer of the interchangeable container, it makes sense to carefully monitor the process parameters within the installation space. In addition to the temperature and the temperature distribution, these process parameters also include the gas pressure in the gas and / or installation space and its temporal progression, the gas composition, but in particular the oxygen content in the gas and / or installation space. An output signal from the gas sensor and / or an output signal from the temperature sensors are preferably present as an input signal to a control unit with which the radiation power of the infrared radiation source can be controlled or regulated in a changed manner depending on the input signals applied thereto. This has the advantage that process deviations can be recognized quickly and easily and counteracted by adjusting the radiation power of the infrared radiation source.

In a further preferred embodiment of the interchangeable container according to the invention, the housing has a plug connection element for connecting an electrical line.

The connector element enables the swap body to be connected quickly and easily to an electrical line. The term electrical line is not limited to connecting lines with a power source, but includes all types of lines through which an electrical current can flow. In particular, this includes data cables via which the interchangeable container can communicate with other devices, but also connection cables via which components of the interchangeable container, such as sensors or heating elements, can be electrically connected to other external units, such as a control unit. A plug connection is easy to establish and disconnect; it enables, in particular, a smooth installation and removal of the interchangeable container, for example in a device for additive manufacturing of a workpiece or in a process station.

It has proven to be advantageous if the swap body container is gas-tight, preferably vacuum-tight.

With many starting materials, it is necessary to remove oxygen from the installation space as completely as possible in order to avoid oxidation of the starting material. For this purpose, an inert gas is usually applied to the installation space and the gas space that is in fluid communication with the installation space. A gas-tight interchangeable container prevents undesired ambient gases, in particular atmospheric oxygen, from entering the installation space of the interchangeable container.

When applying an inert gas to the installation space and the gas space in fluid communication with the installation space, it is essential to ensure that the inert gas is distributed as homogeneously as possible. However, locally it can happen that zones filled with residual oxygen remain. Such zones are also known as “oxygen pockets”. In order to enable a homogeneous inertization of the swap body and in particular to prevent “oxygen pockets”, it has proven to be beneficial if the swap body is made vacuum-tight. This enables the oxygen in the swap body to be removed by evacuation before the inert gas is applied to the construction space and / or the gas space.

It has proven to be particularly advantageous if the housing can be used in a device for additive manufacturing of the workpiece and in a process station for thermal treatment of the workpiece, and if a technical system is integrated into the swap body that enables the exchange of information between the device allowed for additive manufacturing and the process station.

Such a technical system integrated into the interchangeable container allows the exchange of information between the device and the process station, for example on the materials and workpieces contained in the interchangeable container, on the previous or planned heat treatment or on the cooling behavior. This can be implemented, for example, via a bar code or QR code in connection with a database or a CAM system to which both the device and the process station are connected. Alternatively, the data could be written by the device to an RFID tag and then read out by the process station. After the thermal treatment has taken place, this can be stored in the RFID tag, for example to enable further process steps.

With regard to the device for additive manufacturing of a workpiece, the above-mentioned technical problem is achieved according to the invention based on a device for additive manufacturing of a workpiece of the type mentioned at the outset in that it has a receptacle for the removable container.

A device for additive manufacturing of a workpiece with a receptacle for the interchangeable container enables the interchangeable container to be installed and removed quickly and easily. The receptacle therefore particularly preferably has connecting elements which correspond to the connections of the interchangeable container, in particular the media connections and / or the gas connections and / or powder connections, as well as their self-sealing quick-release couplings. This ensures that the device and the swap body can be connected to one another quickly and easily. A major advantage of the receptacle is that the interchangeable container does not have to remain in the device for additive manufacturing until the workpiece is removed from the installation space. Rather, after the actual additive manufacturing, the swap body can be removed from the device for additive manufacturing while maintaining the inert atmosphere and cooled or further treated in an external process station. This increases the productivity of the device for additive manufacturing, since it can be used to a greater extent.

With regard to the process station for a workpiece produced with a device for additive manufacturing, the above-mentioned technical problem is achieved according to the invention based on a process station of the type mentioned at the beginning in that it has a receptacle for the interchangeable container.

A process station with a receptacle for the swap body enables quick and easy installation and removal of the swap body. The receptacle therefore particularly preferably has connecting elements which correspond to the connections of the interchangeable container, in particular the media connections and / or the gas connections and / or powder connections, as well as their self-sealing quick-release couplings. This ensures that the process station and swap body can be connected to one another quickly and easily. The mounting is designed in such a way that when the process station is installed or removed, the inert atmosphere required in accordance with EHS and QM aspects can be maintained in the installation space. In the process station, for example, starting material for additive manufacturing located in the swap body in the run-up to additive manufacturing can be preheated to a required target temperature or an inert gas can be applied to the construction and / or gas space of the swap body. The process station is preferably a consolidation station in controlled cooling of the installation space with an additively manufactured workpiece located therein can take place in an inert atmosphere, while the additive manufacturing device with which the workpiece was manufactured can meanwhile be used productively in parallel for further manufacturing processes.

In this context, it has proven to be useful if the process station comprises a heating unit for introducing energy into the installation space of an interchangeable container arranged in the receptacle, the heating unit of the process station being the heating device of the interchangeable container.

Since a powerful heating device is already provided in the swap body, the process station does not need its own heating device. This makes the process station simpler and cheaper than comparable process stations with their own heating unit.

With regard to the system for additive manufacturing and machining of a workpiece, the above-mentioned object is achieved according to the invention in that the system comprises a device according to the invention for additive manufacturing of a workpiece and / or a process station according to the invention and at least two replaceable containers according to the invention.

The at least two swap bodies are preferably identical in construction. This has the advantage that a first of the at least two interchangeable containers when it is inserted into the device for additive manufacturing of a workpiece; can be removed from the device for additive manufacturing after completion of the production of a workpiece and immediately replaced by a second of the at least two interchangeable containers. The device for additive manufacturing can thus be used directly for further additive manufacturing.

It has proven useful if the at least two swap bodies for holding powdery starting material with a powder temperature in the range from 10 ° C to 1,000 ° C, preferably from 10 ° C to 900 ° C, particularly preferably from 300 ° C to 800 ° C, is designed. Such swap bodies are also suitable for processing raw materials with a high melting point.

One of the at least two interchangeable construction containers is advantageously a production container in which the workpiece can be produced additively. With the start of additive manufacturing, the production container contains powdered starting material and an additively manufactured object. The powdery starting material and the additively manufactured object can be warm (e.g. in additive manufacturing) or cold (e.g. after cooling down).

It has proven to be advantageous if one of the at least two interchangeable construction containers is a powder storage container for holding powdery starting material for additive manufacturing of the workpiece. The powder storage container is used to provide powdery starting material; it is only filled with the powdery starting material. The starting material can be cold (e.g. when the powder storage container is freshly filled) or it can be warm (e.g. when it is preheated).

It has also proven to be advantageous if one of the at least two interchangeable construction containers is a residual powder container for receiving excess, powdery starting material. The residual powder container is essentially empty. The empty residual powder container can be cold or warm (preheated).

The system can comprise several production containers, several powder storage containers and / or several residual powder containers. At least one of the aforementioned containers is preferably arranged in the receptacle of the process station.

It has proven particularly useful if the process station and / or the device for additive manufacturing is assigned a common or a separate removal and / or supply device, which is designed so that it can be used to hold a removable container for the process station or the Recording of the device for additive manufacturing can be supplied or removed from it.

Advantageously, the process station and / or the device for additive manufacturing comprises a cooling station and / or a preparation station in which an interchangeable container arranged outside the respective receptacle can be heated.

The feed device is particularly preferably designed in such a way that it can be used to convey a swap body container from a preparation station for receiving the process station and / or for receiving the device for additive manufacturing.

The removal device is advantageously designed in such a way that it can be used to convey a swap body container from the receptacle of the process station or the receptacle of the device for additive manufacturing to a cooling station.

Figure list

• 1 einen Ausschnitt einer Temperier-Einheit, wie sie in einem erfindungsgemäßen Wechselbaubehälter einsetzbar ist,
• 2 eine erste Ausführungsform eines erfindungsgemäßen Wechselbaubehälters,
• 3 eine Ausführungsform eines erfindungsgemäßen Systems für die Additive Fertigung und Bearbeitung eines Werkstücks,
• 4 eine zweite Ausführungsform eines erfindungsgemäßen Wechselbaubehälters, und
• 5 eine dritte Ausführungsform eines erfindungsgemäßen Wechselbaubehälters.

The invention is explained in more detail below on the basis of exemplary embodiments and drawings. It shows in a schematic representation:

• 1 a section of a temperature control unit, as it can be used in a swap body according to the invention,
• 2 a first embodiment of a swap body according to the invention,
• 3 an embodiment of a system according to the invention for additive manufacturing and machining of a workpiece,
• 4th a second embodiment of a swap body according to the invention, and
• 5 a third embodiment of a swap body according to the invention.

In 1 a temperature control unit is shown, the total of the reference number 1 assigned. The temperature control unit 1 can be part of a swap body according to the invention; it is particularly suitable for converting existing swap bodies into a swap body according to the invention.

The temperature control unit 1 includes a build platform 22nd , a lifting device 43 for the build platform 22nd , a heater 49 and a cooling device 50 .

The build platform 22nd limits the installation space 19th at its base 20th . The build platform 22nd can with the lifting device 43 in the directions of the double arrow 42 be moved. The lifting device 43 is designed as a hollow cylinder; the top surface 39 the hollow cylinder is closed; the base area 38 of the hollow cylinder is with a base plate 40 connected. The cavity is marked with the reference number 41 marked. On the outer walls of the lifting device 43 including the top surface 39 is an insulating layer 37 applied from ceramic.

The partition 28 has the shape of a quartz glass hollow cylinder; it limits the installation space 19th on the lateral surface side (see lateral surface 21 ). The partition 28 is transparent to infrared radiation and UV radiation.

The heating device 49 includes a platform heater 47 and a jacket heater 44 . The platform heater 47 is the build platform 22nd assigned. For sealing the installation space 19th is the platform heater 47 with a circumferential seal 36 made of fiberglass. The platform heater 47 includes resistance heating elements 46 . In addition, heating is in the platform 47 a temperature sensor 45 integrated, which makes it possible to adjust the temperature in the area of the platform heating 47 capture. The one from the temperature sensor 45 Recorded temperature values are used to regulate the heating power of the platform heater 47 based on. The mantle heater 44 comprises four equidistantly arranged omega emitters 34 with a lamp tube diameter of 10 mm, the ends of which with the electrical connection cables are bent up or down by 90 ° in order to achieve the most compact possible construction (not visible here). The emitters have a power density of 26 W / cm heating filament. About the ones from the Omega emitters 34 The omega emitters are used to guide emitted radiation in the direction of the installation space 34 with a reflector layer 32 made of gold or opaque quartz glass.

The cooling device 50 includes a cooling collar 35 . The mantle heater 44 is held by a cooling collar 35 enclosed. This separates the jacket heating 44 thermally from the immediate vicinity of the temperature control unit 1 , but especially from a device for additive manufacturing or a process station, if a temperature control unit 1 comprehensive swap body is used in it. The cooling sleeve has a plurality of cooling channels that are fluidically connected to one another 33 on. Similar cooling channels can also be found in the platform heater 47 integrate. The cooling collar 35 is on its inside with a reflective coating 29 provided that causes most of the on the reflective coating 29 incident radiation in the direction of the installation space 19th is reflected. This contributes to the energy efficiency of the device, since only a small proportion of the radiant power of the heating device 49 the cooling collar 35 heated and ultimately has to be cooled by this.

2 shows a schematic representation of a first embodiment of a swap body according to the invention, to which the reference number as a whole 70 assigned. The swap body 70 is for additive manufacturing of a workpiece 104 designed; however, it can also be used as a powder storage container or residual powder container. The swap body 70 is gas and vacuum tight; it has a cylindrical housing 101 with a hollow cylindrical housing wall 101a . The cylinder base plate forms another housing wall 101b , the one with the hollow cylindrical housing wall 101a is welded. Both the housing wall 101a as well as the cylinder base plate 101b are made of steel or aluminum. In addition, the housing 101 a lockable cover 71 in the form of a screw cap that connects to the housing wall 101a is screwable. The screw cap is made of steel; it includes a circular base plate 71a by an annular rim 71b is surrounded. The annular edge 71b and the hollow cylindrical housing wall 101a are provided with corresponding screw threads. For gas-tight connection of hollow cylindrical housing walls 101a and cover 71 is the annular rim 71b the cover 71 provided with a sealing element (not shown). The screw cap makes it easier to fill the interchangeable container, but in particular to repair, convert or replace the temperature control unit arranged therein 1 . The temperature control unit 1 is identical to the in 1 temperature control unit shown. To the description of the temperature control unit above 1 is referred.

The case 101 has multiple media connections 140 for the supply and discharge of a cooling fluid, which are provided with quick-release couplings. To facilitate the electrical contacting of the swap body 70 is a connector element 145 intended. In addition, the swap body container 70 with gas connections 151 , 152 provided over which the gas compartment 150 can be evacuated or acted upon with a process gas.

About the electrical contacting of the swap body 70 To facilitate use in several devices, the housing 101 a connector element 145 with which the swap body container 70 can be connected to an electrical line (not shown). The electrical line is used to supply power to the swap body 70 , but also a transmission of data from or to the swap body 70 can via the connector 145 respectively. In addition, the swap body container 70 a technical system that allows the exchange of information between a device for additive manufacturing and a process station. This information can also be accessed via the connector element 145 be transmitted. Examples of such information are the current status of the swap body 70 or data from sensors (not shown) that are integrated in the swap body.

3 shows an embodiment of a system according to the invention for additive manufacturing and machining of a workpiece, to which the reference number as a whole 600 assigned. The system 600 comprises a device for additive manufacturing of a workpiece with a laser unit 201 and a scanner 202 , a process station 250 and several swap bodies 70 , 300 , 400 , of which in 4th exemplarily three are shown. The swap body is shown in detail in 2 shown. The swap bodies 70 , 300 , 400 are identical. The swap bodies 70 , 300 , 400 are suitable for holding powdery starting material with a powder temperature of up to 900 ° C. In addition, the device 200 three shots 203a , 203b , 203c for one swap body each 70 , 300 , 400 on. The recordings 203a , 203b , 203c are provided with connecting elements (not shown), which are connected to the self-sealing quick-release couplings of the media connections, gas connections and powder connections, as well as the plug-in connection elements of the interchangeable containers 70 , 300 , 400 correspond. This enables a particularly simple connection of the interchangeable containers 70 , 300 , 400 with the device 200 . The swap body 70 is used as a manufacturing container; a workpiece is manufactured in it. The swap body 300 is a powder reservoir; it is filled with powdered starting material that is heated to processing temperature. The powdery starting material is used in the additive manufacturing of the workpiece in the swap body 70 provided. The swap body 400 is a residual powder container that holds powdery raw material that is stored in the swap body during additive manufacturing 70 is excess.

The swap body 70 with a workpiece additively manufactured therein, the device is then used 200 to a process station 250 , for this purpose a cooling and consolidation station. During transport it is with the connector 145 of the swap body 70 a transport unit 204 connected, which includes a control unit in addition to an accumulator for the provision of electrical energy, with the recorded process parameters such as the gas pressure in the gas space or temperatures at different locations within the swap body 70 can be monitored. The transport unit is removed from the swap body again after transport 70 Cut.

The cooling and consolidation station, which in total is the reference number 250 is assigned is to accommodate the swap body container 70 out 2 designed. It shows like the device 200 Recordings 203d , 203e for swap bodies 70 , 300 , 400 on. In the consolidation station 250 the workpiece runs through a temperature program with defined cooling rates and holding times under an inert atmosphere. After cooling down, the workpiece is taken out of the swap body 70 removed and the latter can be set up for a new additive manufacturing of another workpiece.

In 4th a second embodiment of a swap body according to the invention is shown, to which the reference number as a whole 504 assigned. Inside the swap body 504 there is a temperature control unit 1 according to 1 . The swap body 504 is with a device connected for additive manufacturing of a workpiece (not shown); he's from below to the ground 501 the device for additive manufacturing is "docked". The top of the swap body is with a lid 500 closed, which is removed before additive manufacturing. The powdered starting material is provided by the coater 502 who do this in the direction of the arrow 503 is moved. In an alternative embodiment of the swap body according to the invention 504 (not shown) represents the cooling device 50 the temperature control unit 1 at the same time represents the housing wall of the swap body or part of it. The z-stroke must be transferred to the stamp on which the construction platform is attached. This can either be done by a lifting device integrated in the swap body ( 4th ) or the stamp is guided through a gas-tight, mechanical bushing in the housing of the swap body. Such an implementation of the stamp has the in 5 illustrated swap body 505 on.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely 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

• US 2008/0190905 A1 [0011]
• US 2018/0161934 A1 [0012, 0013]
• DE 102017211381 A1 [0031]

Non-patent literature cited

• DIN EN 1330-8: 1998 [0023]

Claims (15)

Replaceable construction containers (70; 300; 400; 504; 505) for the additive manufacturing of a workpiece (104), comprising: - a housing (101) which surrounds a construction space (19) with a base area (20) and an outer surface (21) - A construction platform (22) which delimits the installation space (19) on the base side, and - a heating device (49) with a jacket heater (44) assigned to the jacket surface (21) of the installation space (19), characterized in that the housing (101) has a closable cover (71; 500) and the jacket heater (44) comprises an infrared radiation source and / or a UV radiation source, with between the infrared radiation source and / or the UV radiation source on the one hand and the installation space (19) on the other hand, a partition (28) made of a material transparent to infrared radiation and / or UV radiation is arranged. Swap body containers (70; 300; 400; 504; 505) according to Claim 1 , characterized in that the heating device (49) comprises a platform heater (47) assigned to the building platform (22). Swap body containers (70; 300; 400; 504; 505) according to Claim 1 or 2 , characterized in that the housing (101) is provided with a cooling device (50). Interchangeable construction container (70; 300; 400; 504; 505) according to one of the preceding claims, characterized in that the construction platform (22) is provided with a cooling unit. Swap body container (70; 300; 400; 504; 505) according to one of the preceding Claims 3 or 4th , characterized in that the housing (101) has one or more media connections (140) for the supply / discharge of a cooling fluid. Interchangeable container (70; 300; 400; 504; 505) according to one of the preceding claims, characterized in that the housing (101) has one or more powder connections for the inert removal of powder from the installation space (19) and / or for the return of Has powder in the installation space (19). Swap body container (70; 300; 400; 504; 505) according to one of the preceding claims, characterized in that it is gas-tight, preferably vacuum-tight, and / or the housing (101) has one or more gas connections (151; 152) for the Supply or discharge of a process gas includes .. Device (200) for the additive manufacturing of a workpiece (104) with a laser beam source (201) or an electron beam source, having a receptacle (203a; 203b; 203c) for a removable container (70; 300; 400; 504; 505) according to one of the previous Claims 1 to 7th . Process station (250) for a workpiece (104) produced with a device (200) for additive manufacturing, having a receptacle (203d; 203e) for a swap body (70; 300; 400; 504; 505) according to one of the preceding Claims 1 to 7th . Process station (250) after Claim 9 , characterized in that it comprises a heating unit for introducing energy into the installation space (19) of an interchangeable container (70; 300; 400; 504; 505) arranged in the receptacle (203d, 203e), the heating unit being the The process station (250) is the heating device (49) of the swap body container (70; 300; 400; 504; 505). System (600) for additive manufacturing and machining of a workpiece (104), comprising - a device (200) for additive manufacturing of a workpiece according to Claim 8 and / or a process station (250) according to one of the preceding Claims 9 or 10 and - at least two swap bodies (70; 300; 400; 504; 505) according to one of the preceding Claims 1 to 7th . System (600) according to Claim 11 , characterized in that the at least two swap bodies (70; 300; 400; 504; 505) for receiving powdery starting material with a powder temperature in the range of 10 ° C to 1,000 ° C, preferably for receiving powdery starting material with a powder temperature are designed in the range from 10 ° C to 900 ° C. System (600) according to one of the preceding Claims 11 or 12th , characterized in that the process station (250) and / or the device (200) for additive manufacturing is assigned a common or a separate removal and / or supply device, which is designed so that it can be used as a removable container (70; 300; 400; 504; 505) of the receptacle (203d; 203e) of the process station (250) or the receptacle (203a; 203b; 203c) of the device (200) for additive manufacturing or can be removed therefrom. System (600) according to one of the preceding Claims 11 to 13th , characterized in that the process station (250) and / or the device (200) for additive manufacturing comprises a cooling station in which an outside of the respective receptacle (203a; 203b; 203c; 203d; 203e) arranged swap body container (70; 300; 400; 504; 505) is heatable. System (600) according to one of the preceding Claims 11 to 14th , characterized in that the removal device is designed in such a way that with it a swap body (70; 300; 400; 504; 505) from the receptacle (203d; 203e) of the process station (250) or the receptacle (203a; 203b; 203c) of the apparatus (200) for additive manufacturing can be conveyed to a cooling station.

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