DE102019212680A1 - Device for the production of objects by building them up in layers from powdery material with binder jetting and sintering / melting - Google Patents

Abstract

The invention relates to a generic device for producing objects by building them up in layers from powder material by means of an irradiation device, the device for producing objects (24) further comprising a binding agent application device (30) for the locally selective application of binding agent (32) to the last for updating of the construction site prepared material powder layer (20) in a cross-sectional area of the relevant object (24) or possibly the relevant objects assigned to this layer, the binding agent being suitable for solidifying and / or bonding at least one type of material powder, preferably the first type of Material powder. The invention also relates to a corresponding method.

Description

• - ein Bauvolumengehäuse mit einer seitlichen Umfangswandung,
• - eine Basisplattenanordnung mit einer Basisplatte zur Stützung eines Baufeldes, wobei die Umfangswandung und die Basisplattenanordnung relativ zueinander mittels einer Antriebsanordnung bewegbar sind, um das innere Volumen des Bauvolumengehäuses oberhalb der Basisplattenanordnung zu variieren,
• - eine Funktionseinrichtung mit einer Pulverschichtenpräparationseinrichtung zur Bildung einer jeweiligen Werkstoffpulverschicht zur Aktualisierung des Baufeldes,
• - eine Bestrahlungseinrichtung zur ortsselektiven Bestrahlung der jeweils zuletzt zur Aktualisierung des Baufeldes präparierten Werkstoffpulverschicht in einem dieser Schicht zugeordneten Querschnittsbereich des betreffenden herzustellenden Gegenstandes oder ggf. der betreffenden Gegenstände mit Strahlung, insbesondere mit Laserstrahlung, wobei die Strahlung geeignet ist, mindestens eine erste Art von Werkstoffpulver in diesem Querschnittsbereich durch Erhitzen zum Verschmelzen oder zum Versintern zu bringen, und
• - einem oberen Prozessraumgehäuse zur Bereitstellung eines während eines Bauprozesses gegenüber der Außenumgebung abgedichteten Hohlraumes über dem Baufeld.

The invention relates to a device for manufacturing objects by building them up in layers from powdered, in particular metallic and / or ceramic material or from material powder in a building process, comprising:

• - a structural volume housing with a lateral peripheral wall,
• - A base plate arrangement with a base plate for supporting a construction field, wherein the peripheral wall and the base plate arrangement are movable relative to one another by means of a drive arrangement in order to vary the inner volume of the building volume housing above the base plate arrangement,
• - a functional device with a powder layer preparation device for the formation of a respective material powder layer for updating the construction area,
• - an irradiation device for the location-selective irradiation of the material powder layer last prepared to update the construction area in a cross-sectional area of the relevant object to be manufactured or possibly the relevant objects with radiation, in particular with laser radiation, which radiation is suitable for at least one first type of material powder to fuse or sinter in this cross-sectional area by heating, and
• - An upper process space housing for providing a cavity above the construction field that is sealed off from the outside environment during a construction process.

The invention relates in particular to a device for the production of shaped bodies according to the principle of selective laser melting or selective laser sintering. The prior art relating to the field of selective laser melting can refer to, for example, DE 199 05 067 A1 , DE 101 12 591 A1 , WO 98/24574 A , DE 10 2009 038 165 A1 , DE 10 2012 221 641 A1 , EP 20 52 845 A2 , DE 10 2005 014 483 A1 or WO 2017/084781 A1 to get expelled.

It is known that with the method of selective laser melting moldings such as machine parts, tools, prostheses, pieces of jewelry etc. can be produced in accordance with geometry description data of the corresponding moldings by building up layers of metallic or ceramic material powder, with several layers of powder being applied one on top of the other in one production process and each powder layer is heated with a normally focused laser beam in a predetermined area, which corresponds to a selected cross-sectional area of the model of the shaped body, before the application of the next powder layer, so that the material powder in the irradiated areas is remelted to form cohesive solidified sections. The laser beam is guided over the respective powder layer in accordance with the geometry description data of the selected cross-sectional area of the shaped body or possibly data derived therefrom. In selective laser melting, the material powder is normally applied as a binder- and flux-free, metallic, ceramic or mixed metallic / ceramic material powder and heated to its melting temperature by the laser beam, the energy of the laser beam being selected so that the material powder is at the point of impact The laser beam is melted as completely as possible over its entire layer thickness. A protective gas atmosphere, e.g. argon atmosphere, is usually maintained above the zone of interaction between the laser beam and the material powder.

Instead of melting the material, it is also known to build up an object in a comparable way, but to trigger a sintering process using the laser. For this, however, mixed materials usually have to be used as material powder.

In the prior art it is also known to produce objects from powdered starting material by means of binder jetting. Material powder is also applied in layers. In principle, this can be a different material powder than for selective laser melting. However, a metallic and / or ceramic shaped body can also be built up by means of binder jetting by using a metallic and / or ceramic material powder.

Instead of fusing, the connection is brought about by gluing using a binding agent.

For this purpose, for example, the applied powder layer is scanned over or scanned with a print head similar to an inkjet printer, the print head emitting a binding agent or a binder that glues or connects the material powder.

However, a material powder mixed directly with the binding agent can also be dispensed and the powder layer is acted upon selectively in a manner which activates the binding agent in order to bring about a connection / gluing. This can, for example, be produced with a UV lamp which scans the powder layer provided with UV-activatable binding agent in a manner similar to a print head that emits the binding agent.

The light or light source used for this purpose differs from the usual laser used for laser melting, however, because the activation often depends on the wavelength of the light and / or because the activation of the binder often requires a considerably lower temperature than, for example, melting temperatures of the usual ones ceramic or metallic material powders.

By applying / activating the binder at the desired positions of a layer, a solidification in the desired area can be achieved in the same way as when melting corresponding positions in selective laser melting. In a manner similar to selective laser melting, an object can then be built up in layers by solidifying the required areas in each layer.

Depending on the material powder, binder and the desired properties of the object to be manufactured, a body (called green part) and / or area that has been consolidated by the binder must then be further treated, for example in order to reduce the proportion of binder. This can be done by sintering in a sintering furnace.

There are fundamental technical differences between the two processes, both in terms of the process and the technology itself and in terms of the result or the manufactured item.

For example, laser melting requires a material powder and thus a material for the object that can pass into a molten state or at least become sufficiently soft when heated and then has correspondingly desired properties. This means that all materials are ruled out for laser melting that result in undesirable changes in state due to heating, for example many types of plastic.

In contrast, binder jetting uses a material rather than material powder for which suitable binders exist.

Due to the high temperatures, selective laser melting often has considerable requirements with regard to the atmosphere in the bulk housing, as e.g. oxidation reactions of the often metallic material must be avoided.

In the case of binder jetting, however, such high temperatures do not necessarily occur. In contrast, the atmosphere in the work area must not be disruptive for the application of the binding agent, for example with regard to circulation, pressure and properties of the corresponding protective gas.

Depending on the type of binder, it may be necessary to apply it at a sufficient distance from any powder application device so that the powder application device does not clog

Due to the fundamentally different technical processes, there are also considerable differences with regard to the properties of the manufactured objects.

The density and thus, under certain circumstances, the stability / strength of objects manufactured by means of binder jetting can be lower, because depending on the exact material powder and binder, such an object ultimately consists not only of the material of the material powder but also of the binder. This can be reduced by appropriate baking / sintering of the manufactured objects.

However, this leads to changes in volume, as a result of which this is only an option for objects for which the change in volume is unproblematic. Furthermore, this means that the heat resistance of the object depends not only on the material powder, but also on the possibly remaining binder, its proportion and distribution within the finished object and the length and intensity of any sintering (of which the amount of remaining binder can depend).

Objects produced by melting, on the other hand, can immediately have a high strength, since they consist entirely of the corresponding material of the material powder, whereby a high stability can be achieved with metallic or ceramic material powder without a change in volume.

Their heat resistance results from the chosen ceramic or metallic material and can accordingly be chosen to be sufficiently high for the desired application.

On the other hand, when melting, the energy expenditure is of course much higher, the technical requirements with regard to the atmosphere are considerably higher and the time expenditure is also considerably higher. Overall, this leads to higher costs.

Furthermore, when melting, the color and surface properties are determined by the selected material, because the high temperatures generally rule out the addition of dyes or other agents that change the material.

With binder jetting, on the other hand, another additive can easily be added for different layers or different areas within a layer, so that, for example, some parts of the object have one color and other parts have a different color, even though the object is made from the same basic material is constructed.

The prior art relating to the field of binder jetting can, for example, refer to US 2005/0280185 A1 or the U.S. 5,387,380 A to get expelled.

Due to the different advantages and disadvantages of binder jetting and melting, the task arises of specifying a device and a method which open up access to the advantages of both methods with the least possible effort and as compactly as possible, with the use of the Advantages of both methods in the production of one and the same object should in principle be possible.

This object is achieved by a device according to claim 1 and / or a method according to claim 15. Advantageous configurations are the subject matter of the dependent claims.

According to the invention, the generic device for the production of objects is designed in such a way that the device for the production of objects further comprises a binding agent application device for the preferably location-selective application of binding agent to the material powder layer in a cross-sectional area of the object in question or, if applicable, of the objects in question, which is Binder is suitable for solidifying and / or connecting at least one type of material powder, preferably the first type of material powder.

As a result, with the aid of the device according to the invention, both objects with binder jetting and with melts can optionally be produced in layers, which in particular avoids the need for separate devices for this.

According to a preferred embodiment, the device according to the invention is further designed in such a way that the functional device comprises at least one powder delivery surface through which the material powder can be applied to the construction field, the binding agent application device comprising at least one binding agent delivery surface through which the binding agent can be applied selectively to the construction field, wherein the binder release surface is of essentially the same shape as the powder release surface, preferably such that the powder surface provided with powder from one position of the powder release surface on the construction field can be completely provided with binder from one and preferably the same position of the binder release surface, preferably in the form of a powder release surface and the binder delivery surface have a substantially similar shape such that they differ only by a scaling factor.

A layer can be formed very quickly by means of binder jetting because the powder and binding agent can be applied at the same speed, with the binding agent being applied selectively to the desired locations using the corresponding areas of the binding agent release area, thanks to an essentially identical shape of the powder release surface and the binding agent release surface .

The exact surface shapes may differ depending on the different properties of the material powder and binding agent with regard to the release. For example, when the binding agent and the material powder require a different size delivery area for an equivalent throughput.

According to a preferred embodiment, the device according to the invention is further designed in such a way that the functional device comprises at least one slide by means of which the material powder is distributed and / or smoothed on the construction field, the binding agent release surface preferably being arranged in relation to the slide opposite to the powder release surface. In this case, the binding agent delivery surface can extend similarly to the slide and / or like a rear edge opposite its usual direction of movement and in particular can also be configured parallel to it.

The powder distribution or formation of a layer of the desired thickness often takes place in generic devices by simply moving a powder heap or a powder accumulation over the construction field. The rear edge of the slide or the slide (if several or multi-part slides are used) generally defines or determines the extent of the partial surface of a powder layer prepared by means of a movement of the slide.

By means of a design of the binding agent release surface that is essentially equivalent to the slide It can be achieved that this entire area can potentially always be provided with binding agent quickly and selectively to the desired extent without the need to move the binding agent application device transversely to the direction of movement of the slide.

As a result, the binding agent delivery surface or the binding agent application device only has to be moved to the same extent as the slide.

According to a preferred embodiment, the device according to the invention is further designed in such a way that the binding agent application device is designed to dispense binding agent within a unit of time on a material surface that is equal to or larger than a material surface that can be applied within the time unit by means of the functional device, preferably the Surface shape is the same.

This prevents the processing speed or production speed from being limited by too low a maximum speed or maximum amount of the release of binder.

In addition to the above-mentioned variants with a binding agent dispensing surface that matches the powder dispensing surface and / or the shape of the slide, it is also possible, in addition or as an alternative, to move the binding agent application device at a greater speed than the slide or the powder dispensing surface and / or to provide additional movement components, for example orthogonally to a main direction of movement . Then the binding agent application device can, for example, be guided in a first movement behind a slide moved in only one direction and additionally moved orthogonally to cover the entire area behind the slide in order to dispense binding agent quickly enough in the intended areas according to the speed of the Preparation of the material powder surface through the slide.

According to a preferred embodiment, the device according to the invention is further designed in such a way that the binding agent application device comprises a plurality of selectively controllable binding agent dispensing surfaces through which the binding agent can be applied to the construction field.

This makes it possible to cover a large area with several binding agent release surfaces and to release binding agent selectively and at the same time the binding agent release surfaces can be guided more quickly over the entire material powder layer. It is also easier to form different areas of a material powder surface in different ways, namely some by applying binding agent and others by melting.

At the same time, the binding agent delivery surface can nevertheless be designed in accordance with the variants explained above in accordance with the powder delivery surface and / or the slide.

Surface areas that are not covered or formed by binder can then be melted by the laser in the usual way, since such a laser or scanner optics deflecting the light from the laser are generally designed to selectively scan the surface anyway.

It goes without saying that it is also possible to use binding agents which first have to be exposed to additional conditions and / or activated in order to develop a binding effect, such as, for example, heating.

In principle, heating by the laser or its scanner optics provided anyway is possible for this. However, the installation of further light sources and / or lasers designed for activation is preferred and faster in terms of production.

The light source also does not have to activate the binder by heating or purely by heating. It is also possible to use binders that react to certain light and to install appropriate light sources, for example UV light or IR light.

For this purpose, the irradiation device for site-selective irradiation, which is provided anyway, is designed so that it can carry out irradiation in at least two different strengths. On the one hand in a starch suitable for melting and on the other hand in a starch suitable for activating the binder. An additional light source or heating device can thereby be avoided.

The device according to the invention can also be developed in such a way that the binding agent is applied together or mixed with a material powder. For this purpose, it can be provided that, in addition to these combined powder release / binder release surfaces, further areas are only intended for powder. Or the addition of binding agent to the material powder can be switched on and off selectively based on individual delivery areas. Because in areas / for objects in which laser melting is used, the material powder should preferably not be mixed with binder.

In principle, it is a preferred variant that the binder release surface provided according to the invention is at the same time a powder release surface or the powder release surface. This means that in such a variant according to the invention, in addition to the combined binder / powder release surfaces, no further pure powder release surfaces have to be provided. Which means that in some variants according to the invention only combined binder / powder delivery surfaces are provided, which can preferably deliver powder mixed with binder, and in other variants according to the invention, in addition to these combined binder / powder delivery surfaces, further binder delivery surfaces and / or further powder delivery surfaces can be provided.

However, it can also be provided to use binding agents which evaporate under the action of the laser.

It is also possible to provide two types of powder dispensing surfaces, so that in addition to material powder of a first type, material powder of a second type can be dispensed. One material powder can be designed for treatment with a binder and the other for melt treatment.

Then, to a certain extent, imprecise or incorrect delivery of the binder is less problematic, because the binder coming into contact with the material powder of the first type would then not lead to any solidification.

This can be implemented particularly advantageously in the variant in which the binder has to be activated anyway by further irradiation or in some other way and then preferably only connects / solidifies material powder of one of the two types.

Because then even a large-area incorrect distribution of the binder on material powder of the first type remains completely without consequences, since the binder cannot lead to solidification of the material powder of the first type even in the event of incorrect irradiation.

The binder is preferably such that it reacts without problems to the irradiation aimed at melting and evaporates with as little volume development as possible when it is affected by the melting.

In one variant, material powder of the first type can preferably also be applied using a different component than the application of the material powder of the second type.

For example, that the powder layer preparation device is designed to apply the material powder of the first type, and the powder layer preparation device, the binder application device and / or another component of the device is designed to apply material powder of a further type, preferably of the second type.

This allows optimum control of where the material powder suitable for the binding agent and where the material powder suitable for melting / sintering is applied.

Particularly preferably, the binding agent application device and the powder layer preparation device are connected to a common housing or the binding agent application device is part of the functional device, so that a fixed distance along a directional axis between the binding agent application device and the powder layer preparation device and / or at least one binding agent delivery surface of the binding agent application device and at least one powder delivery device and the powder delivery device / or at least one binding agent release surface of the binding agent application device and at least one slide of the powder layer preparation device is defined or formed.

With an appropriately suitable design of the binding agent delivery surface in relation to the slide and / or powder agent delivery surface, this allows a particularly simple sequence of movements, so that overall only one housing has to be moved in an almost conventional manner, as is necessary for the powder layer preparation anyway, and it is only necessary to control the or one of the several binder release surfaces in corresponding areas.

As already mentioned, the device according to the invention is preferably further designed in such a way that the device or the binding agent application device further comprises at least one light source suitable for generating a light which is suitable for activating the binding agent and / or that the irradiation device is also suitable for generating a Light that is suitable for activating the binder.

The first variant is advantageous with regard to the production speed, since specially designed light sources can then be used for the activation. The latter variant is more advantageous with regard to the utilization / utilization of the irradiation device which is already present, but is disadvantageous with regard to the speed.

The device according to the invention is preferably designed in such a way that the binding agent application device comprises a binding agent release surface which is movable relative to a powder release surface and / or a slide of the powder layer preparation device, preferably orthogonal to the directional axis.

In the manner already described, this allows the following binder application device to be rasterized behind the powder dispensing surface and / or the slide.

This can also be combined with the variant with a common housing, in that the binding agent release surface or the multiple binding agent release surfaces are movable within the housing. A mobility orthogonal to the directional axis or to the main direction of movement of the powder dispensing surfaces or the slide is preferred.

The device according to the invention is preferably designed in such a way that the binding agent application device comprises at least one binding release surface, preferably several selectively controllable, such that binding agent can be released along at least one line that extends from one edge of the construction field to another edge of the construction field, preferably to one opposite edge, and / or which is equal to or longer than the maximum diameter of the construction field along a transverse axis which is orthogonal to a main direction of movement of the powder layer preparation device when creating a layer and / or which is orthogonal to the directional axis.

As a result, a single transfer of the binding agent application device from one side of the construction field to the other is generally sufficient to provide all desired surfaces with binding agent. This is particularly advantageous in the variant with only one housing with the powder layer preparation device or in the variant as part of the powder layer preparation device, since the housing or the powder layer preparation device then only has to be moved once across the construction field.

The irradiation device would then preferably follow in a grid-like manner and melt the areas provided for the melting. This optimizes the production or processing speed.

The device according to the invention is preferably developed in such a way that the binding agent application device is elongated with an extension in a longitudinal direction at least twice as large as in a transverse direction, the extension in the longitudinal direction preferably being equal to or greater than a maximum diameter of the construction field along the longitudinal direction .

This is advantageous because it is already a known variant to design the slide in such a way that it is only moved once across the construction field and thus prepares the entire construction field. The binding agent application device is then preferably designed in a similarly elongated manner so that the entire construction area is also covered with regard to the application of binding agent, since then complex movement patterns, especially in the variant with only one housing or as parts of the powder layer preparation device, are avoided, especially if several are selective controllable binding agent release surfaces and / or selectively controllable light sources for binder activation are present.

All of the binder release surfaces described so far can also be designed so that they can release a combination of binder and material powder, in particular a second type, and alternatively also pure material powder, in particular a first type, without a binder. The irradiation device can also be designed in each variant not only for melting but also for sintering or for both.

The device according to the invention is preferably developed in such a way that the device also has a protective gas feed and protective gas discharge device for providing a protective gas atmosphere in the process space housing above the construction field. This enables the use of material powders that react very easily with oxygen.

The device according to the invention is preferably developed in such a way that a powder collecting container is provided below the structural volume housing, which receives the residual powder discharged from the structural volume housing.

The device according to the invention is preferably further developed in such a way that the powder layer preparation device is designed to apply only the first type of material powder to form a respective material powder layer, the material powder being a metallic and / or ceramic material powder.

The device according to the invention is preferably further developed in such a way that the device further comprises a sintering furnace which is connected to and / or integrally with and / or arranged separately from the structural volume housing and / or the process space housing. In particular, it can be provided that the object is sintered directly on the construction field and / or the base plate after construction by means of binder jetting.

The device is particularly preferably designed and / or set up in such a way that a user can choose whether an object can be produced from the same metallic or ceramic material powder by means of melting or by means of binder jetting. This allows first prototypes to be produced quickly using binder jetting and then objects corresponding to the prototypes with the help of more precise laser melting, which in particular does not require subsequent sintering.

A device according to the invention is particularly preferably designed such that several objects can be formed at the same time and preferably some of them by means of binder jetting, some of them by means of laser melting and / or some of them by means of binder jetting and laser melting. This can preferably take place in such a way that the device according to the invention and preferably a control unit is designed such that laser melting is used to manufacture an object in a sub-area of a construction site and binder jetting is used in another sub-area of the construction site, with both items preferably after Completion are separated and only that produced by means of binder jetting is subjected to sintering.

The device according to the invention is preferably designed in such a way, in particular with regard to a laser power, that the laser melting leads to a material density of more than 99% in the areas solidified by laser melting. The device according to the invention is preferably designed in such a way, in particular with regard to the binder used, that the binder jetting without sintering leads to a material density in the areas consolidated by binder jetting of more than 80%, 85%, 90%, 95% and / or 98% leads, material powder and binding agent preferably being designed and / or selected in such a way that subsequent sintering leads to volume losses of less than 20%, less than 10% and / or less than 5%.

A laser power and the material powder and the binding agent are preferably designed and / or selected in such a way that laser melting of an area provided with binding agent leads to the binding agent volatilizing and / or the area no longer having any binding agent after solidification.

A device according to the invention in any of the variants according to the invention described so far can also be provided or connected to a control unit, the control unit being designed to control the device to control an object based on an object pattern with area information about areas to be processed by sintering, melting and / or bonding and in doing so, in accordance with the area information, in each case to form the corresponding areas by sintering, melting or binding as sintering areas, melting areas or binding areas. This can in particular also include the control of the binding agent application device so that binding agent is applied in the required selective manner.

This makes it possible for a user to quickly and easily select to what extent which of the two manufacturing processes should be used for an object. In particular, it is possible to use both production methods in one object.

In a preferred variant, the control unit is also designed to form one or more layers by sintering, melting and / or bonding in accordance with the article pattern.

In particular, it can be used here that layers can be formed quickly using binders, while melted layers provide stability. With a suitable alternation of different layers, an object can thus be produced more quickly than with pure melting and in particular also more cheaply, while at the same time better strength can be achieved than with the pure use of binder.

The control unit is also preferably designed to form one or more adjacent lines or parallel surfaces in a layer by sintering, melting and / or bonding in accordance with the object pattern.

This can be used in a similar manner and in combination with layers formed by bonding agents and by melting to optimize costs, speed and / or strength. In particular, an alternation of layers of the different types vertically with respect to the construction field can thus also be achieved. A kind of grid formation is also possible.

Furthermore, the control unit can preferably be designed to form an inner surface and an enclosing surface in a layer by sintering, melting and / or bonding in accordance with the object pattern in such a way that the enclosing surface has the inner surface completely on an inner and / or an outer edge of the inner surface, the inner surface preferably being formed by melting and the enclosing surface by bonding or vice versa.

This is particularly advantageous when certain material properties are required for the surface, while these material properties are not required for the areas remote from the surface.

By this further development according to the invention, however, it is possible to design only the outer areas of the object in this way and to consolidate inner areas in a cost-saving manner only with binding agents.

A method according to the invention for forming an object by building it up in layers from powdered, in particular metallic and / or ceramic material in a building process is characterized in that some layers are at least partially formed by bonding or using binding agents and some layers are at least partially formed by melting and / or sintering or using an irradiation device designed for melting or sintering a first type of material powder. A device according to the invention is of course preferably used for this purpose.

With the method according to the invention, corresponding areas of the object can be formed with the optimal manufacturing method with regard to the desired properties in this area.

In preferred variants, the method can also include some layers being formed entirely by bonding and / or some layers being formed entirely by melting.

This can be optimizing with regard to the production speed, since only one type of connection is used for a specific layer.

In a further preferred variant, the method according to the invention is further characterized in that in at least some layers an inner surface is formed by bonding and an enclosing surface is formed by melting, or an inner surface is formed by melting and an enclosing surface is formed by binding in such a way that the enclosing surface completely encloses the inner surface at an inner and / or an outer edge of the inner surface.

This allows the advantages already outlined with regard to the control unit, that the surface in particular has important desired properties, while with regard to the internal structure, for example, the more cost-effective variant is selected.

However, it is also conceivable that the properties of a material that is slightly solidified by binding agents are desired with regard to the surface, while the inner material is formed from metallic or ceramic material powder by means of sintering / melting, for example for stability purposes. This is particularly useful if the object is to be stable and at the same time to have different colors in different places.

Preferably, the method according to the invention is further developed in such a way that a surface area and / or an inner body area without contact with a certain, several or all surfaces of the object is or will be formed completely by one of sintering, melting and / or bonding.

It is true that the combined use of binding and melting for one and the same object is limited to a certain extent by the fact that the binding agent has to be completely or partially removed from the areas solidified by binding agents in subsequent processes (e.g. sintering in the sintering furnace).

This changes the volume / expansion of the areas solidified by bonding, while the volume / expansion of the areas solidified by melting remains almost unchanged. This means that any combinations of differently consolidated areas are not possible within an object.

However, the extent and problem of the volume change in areas solidified with binder depend on the one hand on the binder, on whether and how much binder may remain in the finished object and on the shape of the object and the differently solidified areas. Thus, despite these aspects, there are applications in which objects with desired properties can be produced particularly quickly and / or inexpensively with a device according to the invention or a method according to the invention, which objects could not be produced or only with greater effort if only bindings or only melts were used.

• 1 zeigt in einer schematischen Schnittdarstellung einen prinzipiellen Aufbau einer erfindungsgemäßen Vorrichtung zur Herstellung von Gegenständen in einem Zustand eines Bauprozesses.
• 2a zeigt in einer schematischen Draufsicht den Blick auf das Baufeld in 1 und
• 2b zeigt denselben Blick zu einem späteren Zeitpunkt bzw. nach Abschluss der gerade in 2a bearbeiteten Schicht.
• 3 zeigt in einer schematischen Darstellung einen alternativen Aufbau einer erfindungsgemäßen Vorrichtung zur Herstellung von Gegenständen in einem Zustand eines Bauprozesses.
• 4a bis 4f zeigen unterschiedliche erfindungsgemäße Pulverschichtenpräparationseinrichtungen, wie sie in einer erfindungsgemäßen Vorrichtung zum Einsatz kommen können, in einer schematischen Ansicht von unten bezogen auf 1 und 3.
• 5a bis 7b zeigen verschiedene mit einer erfindungsgemäßen Vorrichtung bzw. entsprechend einem erfindungsgemäßen Verfahren hergestellte Gegenstände mit unterschiedlich bearbeiteten Bereichen.

Several embodiments of the invention as a whole or of individual components of the invention are described below with reference to the accompanying drawings 1 to 7b explained.

• 1 shows a schematic sectional view of a basic structure of a device according to the invention for producing objects in one state of a building process.
• 2a shows a schematic plan view of the construction field in FIG 1 and
• 2 B shows the same view at a later point in time or after the completion of the in 2a processed layer.
• 3 shows in a schematic representation an alternative structure of a device according to the invention for the production of objects in a state of a building process.
• 4a to 4f show different powder layer preparation devices according to the invention, as they can be used in a device according to the invention, in a schematic view from below based on FIG 1 and 3 .
• 5a to 7b show various objects produced with a device according to the invention or according to a method according to the invention with differently processed areas.

As in 1 As can be seen, the device according to the invention for producing objects comprises in one embodiment a structural volume housing 16 with a lateral peripheral wall 18th . This build volume housing 16 encloses a base plate assembly 13 to support a construction site 7th . An inner volume of the build volume housing 16 is defined by the position of based on 1 base plate assembly movable up and down by means of a piston 13 and the perimeter wall 18th .

A process room housing closes at the top 4th to provide a cavity that is sealed off from the external environment during a construction process 6th above the construction field 7th at.

At build volume housing 16 or process room housing 4th Appropriate supply and discharge lines for process gases, power supply, material powder supply, binder supply and the like are generally connected.

Inside the cavity 6th a protective gas with excess pressure compared to the external environment of the device according to the invention is preferably provided during a manufacturing process, in particular to avoid the presence of oxygen, since some of the preferably used metallic and / or ceramic material powders react very easily with oxygen.

The device according to the invention further comprises an irradiation device 2 to generate radiation 22nd , generally a laser radiation which, as shown graphically, is focused on a small and preferably almost point-shaped area.

Furthermore, a functional device is provided which, in addition to a supply of binding agent 32 and material powder 14th a powder layer preparation device 12 to form a respective material powder layer 20th on the construction site 7th or to update the construction site 7th includes.

Not shown in the figures include the functional device and the irradiation device 2 also in each case at least one drive or the like for moving the irradiation device 2 as well as the powder layer preparation device 12 above the construction site 7th .

As an alternative or in addition to the movable base plate arrangement 13 can also do the above the base plate assembly 13 located elements such as process room housing 4th , Powder layer preparation device 12 and / or irradiation device 2 be designed to be movable up and down.

The irradiation facility 2 can also be used outside the process area 4th be arranged, with coupling windows, deflection devices, mirrors and / or the like on the upper side of the process chamber housing 2 can be provided so that the radiation from the irradiation device hits the construction field 7th can reach.

The powder layer preparation device 12 further comprises a powder dispensing surface 46 for dispensing the material powder 14th on the construction field 7th or on the layers already located there and a slide 36 for smoothing and distributing the material powder 14th .

The powder layer preparation device 12 is generally used for the preparation of a powder layer along the directional axis 44 or in the main direction of movement 44 emotional. Based on 1 this means that the powder layer preparation device 12 from left to right across the construction field 7th drives, with material powder 14th and using the slide 36 smooths. When reaching the right edge of the construction site 7th based on 1 if the powder delivery is stopped, the powder layer preparation device 12 usually slightly raised and moved back to the left, in order to add another layer of powder material accordingly later 20th to raise.

The powder layer preparation device 12 thus generally only moves in one direction or one-dimensional over the construction field 7th away without moving above the construction field 7th move from left to right in other directions.

As in the 2a and 2 B shown, the powder layer preparation device extends 12 across the entire width of the construction site 7th and can be related to in a single movement from left to right accordingly 1 a material powder layer 20th on the entire construction site 7th raise.

According to the invention, the device according to the invention comprises a binding agent application device 30th for the location-selective application of binding agent 32 . In the present embodiment, this is also on the powder layer preparation device 12 arranged and gives the binder 32 via a binder release surface 34 from. Here is the binder applicator 30th related to the directional axis 44 behind the slide 36 arranged while the powder delivery surface 46 in front of the slider 36 is arranged.

This reduces the risk of contamination and clogging of the powder dispensing surface 46 through contact with binding agent 32 and at the same time is the application of the binder 32 onto the already smoothed and prepared material powder layer 20th more precise than applying it to the unsmoothed one to the right of the slider 36 .

Due to the selective controllability of the irradiation device 2 and the selective controllability of the binder application device 30th , here, for example, through control where binders are currently being passed through binder dispensing surfaces 34 is released, objects or even individual layers can be formed selectively either by means of binder jetting and / or by means of melting.

This is in the 2a and 2 B shown in more detail. The powder layer preparation device is on the left 12 one on the construction site 7th formed material powder layer 20th visible.

The binder dispenser 30th was controlled so that in the binder areas 28 or binder areas 28 of the manufactured item 24 the material powder 14th through the binder 32 was solidified.

In contrast, was on the enamel surfaces 26th of the manufactured item 24 no binding agent 32 applied. These were instead from the radiation facility 2 scanned with the laser so that the material powder 14th is solidified there by melting. Part of the material powder layer 20th is processed neither by melting nor by binding.

The binder applicator 30th covers the entire width of the construction site 7th off while the laser 22nd the irradiation device 2 focused on a single point or very small area. Therefore the radiation facility must 2 based on the 2a and 2 B not just left to right movement along the directional axis 44 perform like the powder layer preparation device 12 , but based on 2a and 2 B also from top to bottom and back again.

At the in 2a The situation shown is therefore not yet processed in the upper area of the intermediate ring to be solidified by melting. The next step would be the irradiation facility 2 based on 2a to move upwards in order to carry out a corresponding melting there.

2 B shows the final state. The powder layer preparation device 12 has been moved all the way to the right along the directional axis 44 and there were means of delivery of binder 32 an inner ring and an outer ring as binder areas 28 in the material powder layer to be processed 20th educated.

The irradiation device was used between this inner and outer ring 2 by heating with the focused laser and the resulting melting a melting area 26th educated.

As in relation to 1 As can be seen, repeating this process results in a cylindrical object for all layers, with an inner and an outer cylinder made up of a binder 32 solidified material powder 14th and an intermediate ring, which is also connected in a solidified manner, made of material solidified by melting.

The connection of the different rings results here simply from the fact that only one uniform material powder 14th is used, which means that fusing easily into the binder area at the transition areas 28 reaches into it and thereby results in a stable connection or vice versa.

Previous generic devices both from the area of melting and from the area of binder jetting cannot build such a combined object. Such a combined item offers the Advantages of inexpensive manufacture of the binder cylinder 28 combined with their own surface properties and at the same time the strength and stability of a melting cylinder 26th .

In 3 an alternative embodiment of the device according to the invention is shown. This differs from the in 1 variant shown in that the powder layer preparation device 12 no powder dispensing surface 46 includes. Instead, they are part of the functional device in a wall of the structural volume housing 16 a material powder channel 19th and a material lifter that can be moved up and down in it 17th intended.

In the 3 The device according to the invention shown differs from that in FIG 1 device according to the invention shown essentially in that by means of the lifter 17th through the canal 19th Powder is pushed around a pile of material powder 14th based on 3 on the left edge of the construction site 7th or on the top of the building volume housing 16 left of the construction site 7th to train. The pile of powder is as far as possible over the entire width of the construction field 7th provided.

The powder layer preparation device 12 is moved above this pile of powder when moving to the left and lowered at a suitable point, so that with subsequent movement based on 3 to the right the slider 36 takes a suitable amount of powder with him, necessary for the preparation of the entire construction area 7th or a material powder layer 20th is sufficient.

Care should be taken here that the powder pile is not so high that there is undesirable contact with the binding agent release surface 34 comes.

Otherwise, the use and operation of the in 3 device according to the invention shown similar to that in 1 shown. In particular, the in 3 Device shown also according to the 2a and 2 B be used.

4a to 4f show various powder layer preparation devices that can be used within the scope of the device according to the invention 12 in a view related to 1 and 3 from underneath.

4a essentially corresponds to the powder layer preparation device 12 out 1 . As can be seen, this includes the slide 36 and the powder delivery surface 46 and the binder applicator 30th with binding agent release surface 34 .

As indicated by the hatched areas adjacent to the binder release surface 34 and the powder delivery surface 46 indicated, the corresponding structures are conical, as in the side section in 1 evident. But they extend as in 4a visible over almost the entire width of the powder layer preparation device 12 .

The slider 36 comprises one of the binder application devices 30th facing rear edge 38 . This is parallel to a leading edge 40 the binder delivery surface 34 educated. This parallel design makes it possible that the entire by means of the slide 36 Area of the material powder layer prepared and leveled in one movement 20th also in one motion with binder 32 can be provided.

The binder applicator 30th is also elongated with an extension 48 That is the same size or slightly larger than the width of the construction site 7th based on 2a is from top to bottom.

Here is the binder applicator 30th controllable in such a way that only in part of the binding agent release area 34 Binder is released so that, for example, such binder surfaces 28 or binder areas 28 as in 2a and 2 B shown can be trained.

4b shows a variant of the powder layer preparation device 12 more according to the powder layer preparation device 12 out 3 . It is also related to the directional axis 44 behind the binder applicator 30th a row of light sources of approximately the same length 47 arranged.

This is done using a binder 32 which only develops a binding effect through activation by means of light of special wavelengths, for example UV light or IR light.

The advantage here is, among other things, that if necessary, the selective control of the binding agent application device 30th can be dispensed with, since the selective control of the light sources 47 is sufficient for the formation of correspondingly desired structures, such as those in 2a and 2 B Binder areas shown 28 or binder areas 28 .

4c shows a powder layer preparation device 12 specially designed for creating linear binder areas 28 and melting ranges 26th parallel to the direction axis 44 .

There are several powder dispensing surfaces for each 46 and binder delivery surfaces 34 on the same side of the slide 36 related to the directional axis 44 arranged. These areas are through partitions 56 separated from each other.

These partitions 56 reach down as far as the slide 12 or almost as far. As a result, when the powder layer preparation device is moved 12 in the direction of the direction axis 44 each in an area between two partition walls 56 either just material powder 14th or material powder 14th and binders 32 be handed in.

The partitions 56 Make sure that at most in a small area that the partition walls 56 less far related to 1 and 3 extend downward than the slider 36 , mixing takes place.

This creates clearly defined lines of binding agent 32 prepared material powder 14th and those without a binder 32 educated. In this variant, of course, it is also particularly possible that the binding agent application device 30th directly with binding agent 32 mixed material powder 14th of the same or a different type.

A line-shaped structuring is also possible by means of a powder layer preparation device 12 easily possible with the partitions 56 only related to the directional axis 44 behind the slide 36 are arranged as in 4d shown. In the exemplary embodiment, these only have the effect of contaminating neighboring lines with binding agent 32 to prevent. Because the material powder layer 20th is in the area related to the directional axis 44 behind the slide 36 already smoothed.

However, sliders that are not elongated, straight are also possible 36 and binder delivery surfaces 34 , such as in the 4e shown. Such a powder layer preparation device 12 , as in 4e shown works in principle the same as the one in 3 shown. Only the other geometry can offer advantages, for example in the case of a differently designed construction field 7th or if, for example, the powder layer preparation device 12 just a swivel movement over the construction field 7th should perform.

In 4f is another powder layer preparation device 12 shown in which there is an almost punctiform powder dispensing surface 46 in the middle there. This is spaced apart by the distance 58 from an annular binder applicator 30th with a ring-shaped binding agent release surface 34 surround.

In this way, a quasi-punctiform application of powder is possible, with the ring-shaped binder release surface 34 is preferably aligned so that corresponding binder 32 exactly matching the quasi punctiform application of the material powder 14th is delivered. Such a powder layer preparation device 12 must of course above the construction site 7th a two-dimensional movement when preparing a material powder layer 20th perform, in contrast to the one-dimensional movements of other inventive powder layer preparation devices 12 as in relation to 1 , 2a , 2 B and 3 explained.

A powder layer preparation device 12 , as in 4f shown, can, so to speak, also be designed inversely, with a point-shaped binder release surface 34 in the middle and a ring-shaped powder dispensing surface 46 at a distance 58 outside around.

As an alternative to the solutions of firmly connected powder dispensing surfaces shown in the figures 46 and binder delivery surfaces 34 can also be provided, the binding agent release surfaces 34 designed to be movable, for example movable in a similar manner to the irradiation device 2 . The binder delivery surfaces 34 can then be made smaller overall and would produce the material powder layer in a manner similar to the irradiation device 20th scan.

A device according to the invention can comprise a controller for activation in accordance with the properties and features described, preferably for the production of objects 24 as described.

A method according to the invention preferably uses a device according to the invention in accordance with the described properties and features of the manufacturing process for the objects 24 and the device according to the invention.

In 5a to 7b are various objects constructed by means of devices according to the invention or by means of methods according to the invention 50 shown.

As with the illustrations of the cut surface 60 out 5a in 5b evident is the subject 50 of the 5a on the outside completely of a melting range 52a and only the core, not visible from the outside, is a binding agent area 54a . This configuration is advantageous, especially when it comes to the short-term better heat resistance of a molten material.

Like the in 6b shown cut surface 62 out 6a shows is the subject 50 out 6a only in a thin outer layer and with thin inner walls due to a melting area 52 formed, while the rest of the body is made up of binder areas 54 consists.

This is advantageous when the surface properties of the corresponding molten material are important, but no special strength of the inner areas is required beyond what is necessary to avoid deformations due to its own weight.

As with 7a and 7b visible is the item shown therein 50 alternating in layers from melting areas 52 and binder areas 54 educated.

True, in 7b in the section plane shown there 64 out 7a the melting ranges 52 a greater thickness than the binder areas 54 . However, this is only necessary if the strength is high.

In alternative exemplary embodiments, considerable strength can already be achieved in the relatively thick areas of binding agent 54 with relatively thin melting areas 52 similar to in 7b shown alternate.

This of course offers the advantage of a suitable coordination of costs and effort in production (which increases with more / thicker melting areas 52 ) in relation to the strength (which is also characterized by more / thicker melting areas 52 increased).

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

• DE 19905067 A1 [0002]
• DE 10112591 A1 [0002]
• WO 98/24574 A [0002]
• DE 102009038165 A1 [0002]
• DE 102012221641 A1 [0002]
• EP 2052845 A2 [0002]
• DE 102005014483 A1 [0002]
• WO 2017/084781 A1 [0002]
• US 2005/0280185 A1 [0026]
• US 5387380 A [0026]

Claims (16)

Device for the production of objects (24) by building up in layers from powdered, in particular metallic and / or ceramic material or from material powder (14) in a building process, comprising: - a volume housing (16) with a lateral peripheral wall (18), - a Base plate arrangement (13) for supporting a construction field (7), the peripheral wall (18) and the base plate arrangement (12) being movable relative to one another by means of a drive arrangement in order to vary the inner volume of the structural volume housing (16) above the base plate arrangement, - a functional device with a powder layer preparation device (12) for the formation of a respective material powder layer (20) for updating the construction area (7), - an irradiation device (2) for the location-selective irradiation of the material powder layer (20) last prepared to update the construction area in a cross-sectional area of the relevant Ge object (24) or the relevant objects with radiation (22), in particular with laser radiation, the radiation being suitable for fusing or sintering at least one first type of material powder in this cross-sectional area by heating, and - an upper process chamber housing (4 ) for providing a cavity (6) above the construction field (7), which is sealed off from the outside environment during a construction process, characterized in that the device for manufacturing objects (24) further comprises a binding agent application device (30) for the location-selective application of binding agent (32) onto the material powder layer (20) in a cross-sectional area of the relevant object (24) or the relevant objects assigned to this layer, the binder being suitable for solidifying and / or bonding at least one type of material powder, preferably the first type of material powder. Device according to Claim 1 , characterized in that the binding agent application device is designed to deliver binding agent within a unit of time on a material surface that is equal to or larger than a material surface that can be applied within the time unit by means of the functional device, the surface shape preferably being the same. Device according to one of the preceding claims, characterized in that the binding agent application device comprises a plurality of selectively controllable binding agent release surfaces through which the binding agent can be applied to the construction field. Device according to one of the preceding claims, characterized in that the binding agent is designed to be activatable and / or is designed to solidify the at least one type of material powder only under an active change in state and / or an active effect, in particular heat and / or light . Device according to one of the preceding claims, characterized in that the binding agent application device applies the binding agent by dispensing material powder mixed with binding agent. Device according to one of the preceding claims, characterized in that the powder layer preparation device (12) is designed to apply the material powder of the first type, and the powder layer preparation device (12), the binding agent application device (30) and / or another component of the device is designed to be material powder another way to apply. Device according to one of the preceding claims, characterized in that the binding agent application device and the powder layer preparation device are connected to a common housing or the binding agent application device is part of the functional device, so that a fixed distance along a directional axis (44) between the binding agent application device and the powder layer preparation device and / or at least one binding agent release surface of the binding agent application device and at least one powder release surface of the powder layer preparation device and / or at least one binding agent release surface of the binding agent application device and at least one slide of the powder layer preparation device is defined or formed. Device according to one of the preceding claims, characterized in that the device or the binding agent application device further comprises at least one light source (47) suitable for generating a light which is suitable for curing the binding agent, and / or that the irradiation device is also suitable for generating a Light that is suitable for curing the binder. Device according to one of the preceding claims, characterized in that the binding agent application device comprises a binding agent release surface which is movable relative to a powder release surface and / or a slide of the powder layer preparation device. Device according to one of the preceding claims, characterized in that the device furthermore has a protective gas feed and protective gas discharge device for providing a protective gas atmosphere in the process chamber housing (4) above the construction field (7), preferably the protective gas feed and protective gas discharge device, the binding agent application device and / or the powder layer preparation device is connected to a common housing or the protective gas supply line and protective gas discharge device are part of the functional device. Device according to one of the preceding claims, characterized in that a powder collecting container (17) is provided below the building volume housing (16) which receives the residual powder discharged from the building volume housing (16). Device according to one of the preceding claims, characterized in that the powder layer preparation device (12) is designed to apply only exactly the first type of material powder to form a respective material powder layer (20), the material powder being a metallic and / or ceramic material powder. Device according to one of the preceding claims, characterized in that the device comprises a control unit which is designed on the basis of an object pattern with area information about areas to be processed by sintering, melting and / or bonding the powder layer preparation device (12), the irradiation device (2) and / or to control the binding agent application device (30) for corresponding processing when an object is formed, so that some or all layers are formed at least partially and / or completely by binding and / or using binding agent and / or by melting and / or by sintering. Device according to one of the preceding claims, characterized in that the device comprises a sintering furnace which is connected to and / or arranged integrally with and / or separately from the structural volume housing (16) and / or the process space housing (4). Method for forming an object (24) by building up in layers from powdery, in particular metallic and / or ceramic material in a building process, preferably using a device according to one of the preceding claims, characterized in that some layers are at least partially by binding and / or under Use of binding agent and / or be formed by melting and / or by sintering. Method for forming an object (24) by building up in layers from powdery, in particular metallic and / or ceramic material in a building process using a device according to one of the preceding claims, characterized in that only a material powder of the first type is used and before the start of the layer-wise When building up, it is selected whether all layers are formed by bonding or by melting.

Images