WO2019068692A1

WO2019068692A1 - Device for forming 3d bodies

Info

Publication number: WO2019068692A1
Application number: PCT/EP2018/076754
Authority: WO
Inventors: Thomas Bettermann
Original assignee: Homag Bohrsysteme Gmbh
Priority date: 2017-10-04
Filing date: 2018-10-02
Publication date: 2019-04-11
Also published as: DE102017122944A1

Abstract

The invention relates to a device (1, 1') and a method for forming 3D bodies (100), in particular pieces of furniture, by additive material application. In particular, the device has a support (12, 12') on which the 3D body (100) is formed, an application unit (13, 13') for building up the 3D body on the support by additive application of material, and a cooling unit (14, 14') and a heating unit (15, 15').

Description

Device for the formation of solids

FIELD OF THE INVENTION

The present invention relates to a device for forming solid bodies, in particular of or for elements in the field of furniture or component industry.

STATE OF THE ART

WO 2013/180609 A1 is known, which relates to a method and an apparatus for layering an article. The layered formation of bodies falls within the range of generative methods and can be assigned to the so-called 3D printing.

Such methods are enjoying increasing popularity. The increasing economy and industrial applicability makes 3D printing more and more important not only in prototype development. Also in the field of individual production, the possibilities of 3D printing offer interesting perspectives. This applies above all to prototypes and custom-made furniture and other elements of the component industry.

In the case of the melt layer method (FDM or FFF method), this is about a plastic to be processed melted and layered on a carrier or already formed layer of plastic.

In order to be able to form complicated geometries with high accuracy in such a 3D printing process, the temperature at which this application takes place, in addition to the application speed of great importance. Furthermore, not only the temperature at which an additional layer is applied is important, but also the temperature of the already applied layers. There are various challenges in the prior art.

If the temperature of the applied layer is too low, the heat of the material to be applied may not be sufficient to sufficiently heat the already applied layer. As a result, the material to be applied does not or not sufficiently bond with the applied layer, and it may lead to delamination or at least to instability of the component to be produced.

If the temperature of the applied layer is too hot, then the additional heat of the layer to be applied may lead to these layers joining, but they continue to deform under the influence of gravity and thus no longer represent the actual desired geometry. In addition to aesthetic and structural weaknesses, this leads to another challenge. The controller of the 3D printer usually does not notice such deformation. A next layer to be applied over is thus applied at a greater distance from the underlying, deformed layer. This leads to a sagging of this new layer and thus to an even worse control of the geometry of the component to be created. This effect can be further enhanced with further layers being applied. Thus, it is not always possible in the prior art to form complicated geometries with high accuracy in a 3D printing process.

PRESENTATION OF THE INVENTION

It is therefore an object of the present invention to provide an apparatus which is capable of producing geometrically complex bodies by an additive manufacturing method with a high accuracy.

For this purpose, the present invention provides a device according to claim 1. Further preferred embodiments are given in the dependent claims.

The invention is based on the idea that the above-described challenges in the prior art are primarily due to the fact that an applied layer to which a new layer is to be applied, or an applied layer to which a new layer has previously been applied, has a temperature that is not tampered with, even if that temperature is too low or too high.

The present invention takes advantage of this finding and provides a device for forming solid bodies having a cooling unit and a heating unit, wherein the active site of the cooling unit and / or the effective point of the heating unit is variable around the applicator unit.

In particular, the device for the formation of solids, in particular pieces of furniture, by additive material application thereby: A carrier on which the volume body is formed, a application unit to build up the volume body on the support by additive Application of material, wherein the material is in particular partially formed of wood material, such as wood foam, wood flour, sawdust or the like, a metallic or mineral paste, or plastic, a cooling unit for cooling a portion of the volume body and a heating unit for heating a portion of the volume body.

It is preferred that the heating device is set up and / or arranged to heat a portion of the volume on which a material application is to take place by the application unit. According to one embodiment, the cooling device should be set up and / or arranged to cool a section of the volume on which a material application has been applied by the application unit.

By means of this device according to the invention, an area on the volume body around the application unit can be heated or cooled as required.

The "application unit" in the context of this application is directed to any unit or device with which an additive method for forming solids can be carried out.

The term "solid" is to be understood as a structural body whose dimensions extend beyond a coating consisting of a liquid or solid coating material or a printed surface, in particular, the volume body should have a thickness of at least 500μη.

In particular, the additive material for forming volumetric bodies is lignin-containing material such as wood material, in particular wood foam, wood flour,

Abrasive dust, sawdust, cellulose or the like. Further The additive material may be metal pastes or foams, plastic pastes or foams, pasty material or electrically conductive materials such as copper paste or an electrically conductive plastic or electrically conductive biomaterials and bio-plastics. Another alternative is a carbon fiber-containing material. Furthermore, thermoplastic, thermosetting or elastomeric plastics can be used. However, the present invention is not limited to the use of a particular type of material. Also, the formation of a solid can be done in sections with different materials or the materials are mixed before their order. In further embodiments, it is provided to use aluminum foam, plastic foam, etc., as the material for forming solid bodies, in particular for forming lightweight panels.

It is preferred that the effective range of the cooling unit and / or the effective range of the heating unit is / are adjustable around the application unit. Thus, the respective effective range can be tracked according to the movement of the application unit.

In this case, the cooling unit is preferably designed to cool a region of the volume body to which the application unit has previously applied material, or the heating unit is designed to heat a region of the volume body to which the application unit subsequently applies material. Thus, a deformation of the volume body after application can be prevented, or to ensure a good connection between the applied layer and the material to be applied.

More preferably, the cooling unit or the heating unit is arranged concentrically around the application unit so as to variably cool or heat an area around the application unit. A concentric Arrangement of cooling unit or heating unit can allow a simpler structure of the device.

Furthermore, the cooling unit or the heating unit may have a plurality of elements for cooling or heating arranged around the application unit, each of which is configured to provide a cooling function or a heating function individually. In this case, there need be no moving parts relative to the application unit. This makes possible a low-maintenance device which nevertheless, according to the invention, heats or cools individual desired regions of the volume body.

Alternatively or additionally, the cooling unit or heating unit may be rotatably disposed around the application unit so as to be capable of variably cooling or heating an area on the volume around the application unit.

Thus, it may be possible to use a one-piece cooling element or heating element, which is then movable by rotation relative to the application unit. This can bring the advantage of reduced costs, especially in complex cooling elements or heating elements. For example, the cooling unit may be an eddy current tube capable of cooling the bulk body by a cooled airflow.

The use of an eddy current tube here has the advantage that no further cooling unit with heat exchanger or compressor must be used, and that the air flow thus generated can reach a temperature of -40 ° C, which can be achieved with other cooling units only with much greater effort.

The heating unit may preferably comprise at least one heating element capable of passing through the solid Heat radiation to heat. The use of heat radiation primarily does not generate any air flow, so that, especially with filigree solids, no deformation can take place as a result. The heating of the volume by means of microwaves is possible in this context.

Alternatively or additionally, the heating unit may comprise at least one hot air nozzle which is capable of heating the volume body by a heated air flow. The use of a hot air nozzle can thus enable convective heat transfer, which tends to allow greater heat transfer compared to thermal radiation.

These two possibilities of the design of the heating unit can be chosen variably depending on the field of application of the invention and can also be used together in a device according to the invention, so as to combine the advantages of both types.

According to a preferred embodiment, the device further comprises a feed device, which is connected to the application unit for supplying the material to the application unit, wherein the feed device has an extruder, and / or a particular heatable hose.

The use of a feed device has the advantage that the application unit can be continuously supplied with material, whereby an additive material application without interruption is possible. The provision of an extruder has the advantage that the material can be applied uniformly with defined properties and without interruption, which is particularly advantageous for the formation of complex geometries. The tube also opens up the possibility of forming the feeder heatable. This in turn has the advantage that the Consistency of the material to the additive structure of the solid can be set very defined.

According to an advantageous development of the application unit is connected to the extruder via the particular heatable hose. This opens up the possibility of arranging the extruder separately from the application unit. This can ensure that the application unit can be flexibly aligned without having to carry the extruder. Thus, on the one hand, despite the use of the extruder, a compact application unit can be realized. On the other hand, the orientation of the application unit is not affected by the possibly heavy extruder.

According to a preferred embodiment, the application unit has one or more nozzles.

For example, the nozzle communicates with the feeder. In particular, the nozzle may communicate with the hose or form the end of the extruder. If there are several nozzles, this allows the additive material application of different materials, without having to change the tooling of the device. Thus, for example, with a device (possibly metallic) structures such as tracks or fittings can be constructed, which are then embedded successively in the solid. Each nozzle may have its own feeding device (i.e., corresponding hoses, extruders, storage devices, screw conveyors, etc.) as needed.

It is preferred that a support structure on which the solid is constructed, is detachably arranged on the support so that it can be exchanged or exchanged into the device. Furthermore, the apparatus preferably additionally has at least one thermal sensor configured to detect the temperature of a portion of the solid on which a material application has previously taken place and / or which is configured to detect the temperature of a portion of the solid, hereinafter referred to a material order will take place.

The thermal sensor may be a thermal imaging camera and / or an infrared temperature sensor.

Furthermore, the present invention provides a method of forming bulk solids by additive material deposition, comprising: applying additive material to build a bulk body; Cooling a first portion of the bulk body locally in the area of a current material application site; and / or heating a second portion of the bulk body locally in the area of the current material application site.

This method preferably uses a device as previously shown.

More preferably, the first portion of the volume to be coated next or the portion of the volume just coated.

Even more preferred is the second section of the bulk body to be coated next.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a plan view of a first embodiment of the device for forming solid bodies according to the present invention. Fig. 2 shows a cross-sectional view of the first embodiment of the device for forming solid bodies according to the present invention.

Fig. 3 is a perspective view of the apparatus of the first embodiment for illustrating an application process on a support.

Fig. 4 shows the device shown in Fig. 3 from a lower side.

Fig. 5 shows a plan view of a second embodiment of the device for forming solid bodies according to the present invention.

Fig. 6 shows a side view of the second

Embodiment of the device for forming solids according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Other modifications mentioned in this context can each be combined with each other to form new embodiments.

1 and 2 illustrate a schematic plan view and side view of a first embodiment of a device 1 according to the invention for forming solid bodies 100. For further explanation of the operation of the device 1, reference is additionally made to FIGS. 3 and 4.

The device 1 has a carrier 12, on which the volume body 100 is to be constructed. According to the invention Solid body 100 thereby gradually built up by additive material application. For this purpose, a application unit 13 is provided, which is suitable for applying a defined amount of material at a defined position on the support 12 or the solid 100.

In the first embodiment according to FIG. 1 or 2, an annular heating unit 15, which is segmented, is arranged around the application unit 13.

Segmented in the sense of the present description means that the heating unit has individual segments which can individually provide heating.

This makes it possible for a selectable region of this heating unit 15 to emit heat radiation to an underlying solid 100, which thus can preferably be preheated locally. Such heating is illustrated in FIG. 2 by arrows shown between the heating unit 15 and the solid 100.

A second concentric arrangement around the application unit 13 is a cooling unit 14. Here, the heating unit 15 may be arranged around the cooling unit 14 or vice versa. The cooling unit 14 is designed in this first embodiment as a plurality of nozzles, the individually cooled air approximately from a cooling unit relates (not shown) and delivers to the underlying solid 100. Such cooling is illustrated in FIG. 2 by arrows shown between the cooling unit 14 and the solid 100.

As an alternative to the segmentation of the heating unit 15 and the cooling unit 14, the provision of a rotatable perforated panel on the underside of the heating unit 15 and the cooling unit 14 is also possible. This can be rotatably mounted, allowing escape of hot or cold airflow at a particular position of the heating unit 15 or the cooling unit 14.

FIGS. 1 and 2 further show the schematic forming of the volume body 100. On the left side of these drawings, ie on the side on which the heating unit 15 is activated by the application unit 13, there is at least one already applied layer, which thus forms a part represents the volume 100 to be created. On this applied layer now applied material is applied by the application unit 13. After cooling, whether by means of a cooling unit or without, this previously applied material has now also become part of the volume body. This can be seen on the right side of these drawings, that is on the side on which the cooling unit 14 is activated by the application unit 13.

This device 1 according to the invention in its first embodiment can now selectively preheat a region of the volume body 100 with the heating unit 15, on which a material application is to take place. As a result, the technical effect is achieved that a compound of already applied layer and applied material can be improved. The exact area to be heated can be set via the various segments of the heating unit 15.

Additionally, another portion of the bulk body 100 may be cooled with the cooling unit 14. As a result, the technical effect is achieved that a cooling of a previously applied layer is made possible or accelerated. The exact area to be cooled can be set via the various segments of the heating unit 15. During the cooling and heating of the bulk body 100 shown in FIG. 2, the application unit 13 moves relative to the bulk body 100, thereby further applying a molten material. By a variable cooling or heat output in this case a desired degree of cooling or heating can be adjusted.

For better control of the required cooling or heating, the device 1 may additionally have thermal sensors. The thermal sensors are preferably arranged such that the temperature of the volume body 100 can be measured locally at which a new layer is to be applied and / or that the temperature of the volume body 100 at which a new layer is applied can be measured locally. Thus, an actual state of the temperature of the volume body 100 can be detected and adjusted against a desired state, which makes it possible to adjust the local temperature of the volume body 100 accordingly. In addition to the more precise

Temperature manipulation of the volume 100 thus critical temperatures can be detected and reported to a user. An embodiment of a thermal sensor is about a thermal imaging camera, with an infrared temperature sensor is conceivable, which can detect especially punctual temperatures.

By means of a heat sensor, a controlled system can be created, which enables optimum achievement of such desired temperature values.

Not shown in Fig. 1 or 2 is a coating of a layer which is not on a straight line. Again, the heating or cooling areas of the heating and cooling units 15 and 14 can be selected so that an area is to be applied to the material or was applied to the straight material is manipulated in its temperature. The carrier 12 may have its own heating, which is arranged approximately below the surface of the carrier 12. It is also possible to dispense with such a heater, in particular if the heating unit 15 also preheats a region of the carrier to which a layer is to be applied.

The application unit 13 is shown in FIGS. 1 and 2 only schematically. This application unit 13 may include a nozzle that applies the material and a feeder that supplies the material to the nozzle. The feeder can a

Screw conveyor, a cache

(Storage device), and having an extruder. The feed device is in communication with the application unit 13, which may for example be designed as a shaping opening directly on the extruder or as a nozzle. In this case, the application unit 13 via a suitable hose

(which is considered below as part of the feeder) may be connected to the feeder. On the other side of the application unit in the conveying direction, the feeding device may be in communication with a main storage, not shown, which holds the material to be applied or the corresponding raw material in an appropriate amount. In the main memory can also be a preparation of the material for the construction of the volume body 100 done. This can be done for example by tempering or the addition of other components, binders or additives.

Due to the improved temperature control of the device according to the invention, it may also be possible to carry out a vertical material application. This means that material can be applied perpendicularly or substantially perpendicular to the surface of the carrier 12 (in the vertical direction). Thus, it is possible create complex geometries in which not only printing in the plane of the carrier 12 is performed.

5 and 6 represent a schematic plan view and side view, respectively, of a second embodiment of a device 1 ' ^according to the invention for forming solid bodies 100.

In this second embodiment, in contrast to the first embodiment, the cooling unit 14 ^λ and the heating unit 15 ^{λ are} not concentric and segmented. In this embodiment, the cooling unit 14 ^λ and the heating unit 15 ^{λ are} rotatably arranged around the application unit 13 ^λ . This mobility is illustrated in Fig. 3 by arrows.

In particular, in this second embodiment, an eddy current tube is used as a cooling unit 14 ^λ , which is arranged rotatable about the application unit 13 ^λ . Eddy current tubes are also known as Ranque-Hilsch vortex tubes, use compressed air and require no other mechanical or electrical components. Thus, the complexity of the device 1 ^{λ can be} reduced, although the air flow to be generated can reach temperatures of about -40 ° C. Thus, a quick cooling is possible. The eddy current tube can either have a supply line to be used with compressed air or its own compressor, which generates the required compressed air.

As a heating unit 15 ^λ at least one hot air nozzle can be used in this second embodiment. Also, this is rotatable about the application unit 13 ^λ arranged and can be operated for example with electric current.

The two embodiments described above can also be combined with each other. For example, it may be advantageous, such as a circular segmented Heating unit 15 according to the first preferred embodiment and to use a rotatably movable cooling unit 14 ^λ according to the second preferred embodiment, or vice versa. Customizations to an individual application are possible.

Claims

Device (1; 1 ^λ ) for forming volume bodies (100) by additive material application, comprising: a support (12, 12 ^λ ) on which the volume body (100) can be formed; a plotting unit (13, 13 ^λ ) for constructing the

Bulk body (100) on the support (12, 12 ^λ ) by additive application of material, the material is in particular partially formed of wood material, such as wood foam, wood flour, sawdust or the like, a metallic or mineral paste, and / or plastic; a cooling unit (14, 14 ^λ ) for cooling a portion of the bulk body (100) and a heating unit (15, 15 ^λ ) for heating a portion of the volume body (100).

Device (1; 1 ^λ ) according to claim 1, characterized

characterized in that the effective range of the cooling unit (14, 14 ^λ ) and / or the effective range of the heating unit (15, 15 ^λ ) is adjustable to the application unit.

The device (1; 1 ^λ ) according to claim 1 or 2, wherein the cooling unit (14, 14 ^λ ) is configured to cool a portion of the bulk body (100) to which the application unit (13, 13 ^λ ) has previously applied material , and / or the heating unit (15, 15 ^λ ) is designed such that a portion of the volume body (100) to heat, on the the application unit (13, 13 ^λ ) then applies material.

4. Device (1, 1 ^λ ) according to one of the preceding

Claims, wherein the cooling unit (14, 14 ^λ ) and / or the heating unit (15, 15 ^λ ) are arranged concentrically around the application unit (13, 13 ^λ ), wherein it is preferred that the

Cooling unit (14, 14 ^λ ) outside the heating unit (15, 15 ^λ ) is arranged.

5. Device (1, 1 ^λ ) according to one of the preceding

Claims, wherein the cooling unit (14, 14 ^λ ) and / or the heating unit (15, 15 ^λ ) a plurality of segments for cooling or heating

have / each having such configured, the effective range of the cooling unit (14, 14 ^λ ) and / or the effective range of the heating unit (15, 15 ^λ ) to the

Change order unit.

6. Device (1 ^λ ) according to one of the preceding

Claims, wherein the cooling unit (14 ^λ ) and / or the heating unit (15 ^λ ) is rotatably provided around the application unit (13 ^λ ), so that they are provided, the effective range of the cooling unit (14 ^λ ) and / or the effective range the

Heating unit (15 ^λ ) to change the application unit, in particular according to a direction of movement of the application unit (13 ^λ ).

7. Device (1, 1 ^λ ) according to one of the preceding

Claims, wherein the cooling unit (14, 14 ^λ ) is an eddy current tube intended to cool the portion of the bulk body (100) by a cooled air flow.

8. Device (1, 1 ^λ ) according to one of the preceding

Claims, wherein the heating unit (15, 15 ^λ ) comprises at least one heating element, which is provided, the portion of the

Heat volume (100) by heat radiation.

9. Device (1, 1 ^λ ) according to one of the preceding

Claims, wherein the heating unit (15, 15 ^λ ) has at least one hot air nozzle, which is provided, the portion of the

Volume (100) to be heated by a heated air flow.

10. Device (1, 1 ^λ ) according to one of the preceding claims, further comprising

a feeding device for supplying the

Material for application unit (13, 13 ^λ ) with the

Application unit (13, 13 ^λ ) is connected,

wherein the feeder comprises:

an extruder, and / or

a, in particular heatable, hose.

11. Device (1, 1 ^λ ) according to claim 10,

wherein the application unit (13, 13 ^λ ) is connected to the extruder via the, in particular heatable, hose.

12. Device (1, 1 ^λ ) according to one of the preceding claims, wherein

the application unit (13, 13 ^λ ) has one or more nozzles. Device (1, 1 ^λ ) according to one of the preceding claims, wherein the device additionally at least one

Heat sensor that is set up, the

To capture the temperature of a section of the solid on the previously a material order

has taken place, and / or is adapted to detect the temperature of a portion of the volume on which a subsequent material application will take place.

14. Device (1, 1 ^λ ) according to claim 13,

wherein the thermal sensor is a thermal imaging camera and / or an infrared temperature sensor.

A method of forming bulk solids (100) by additive material application, preferably using a device according to any one of claims 1 to 14, comprising:

Applying an additive material to build up a bulk body (100);

Cooling a first portion of the bulk body (100) locally in the region of a material application site;

and or

Heating a second portion of the bulk body (100) locally in the area of the material application site.

The method of claim 15, wherein the first portion is a portion of the bulk body (100) to which the additive material is next applied or a portion of the bulk body (100) to which the additive material has been applied.

17. The method according to claim 15 or 16, wherein the second

Section is a section of the solid (100) to which an additive material is next applied.