DE202015009361U1 - Device for forming a 3D body - Google Patents

Abstract

Device for forming a 3D body (7) from a fusible and / or curable powdery material (4) comprising: - a housing defining a matrix space (2) with a matrix consisting of X coordinates, Y coordinates and Z coordinates ( 1) for receiving the fusible and / or curable material (4), - a control device for defining the 3D body (7) defining, each having an X-coordinate, Y-coordinate and Z-coordinate matrix points (5) in the matrix space (2), - at least two ultrasound transmitters (3.1, 3.2 to 3.n) for acting on the fusible and / or curable material (4) at the matrix points (5) with superimposed and at least partially sequentially directed to the matrix points (5) ultrasonic waves Fusion and / or curing of the fusible and / or curable material (4) and initial molding of the 3D body (7) in the housing (1).

Description

The present invention relates to a device for forming a 3D body of a fusionable and / or curable material according to claim 1.

In the generative production of 3D bodies (also called additive manufacturing), an object is created by adding, applying and depositing material on the basis of a digital model. In contrast, in subtractive processes, raw material (for example, by milling, turning, drilling) is machined by mechanical removal of material.

As a rule, a digital 3D model, which is translated into machine-readable code and processed automatically, serves as the template for the production.

In addition to additive and subtractive methods, a distinction is still made between forming methods and hybrid methods.

The generative methods include powder 3D printing processes such as selective laser sintering (SLS), electron beam melting (EBM), 3D printing by means of fused filament fabrication (FFF), or fused filament fabrication (FFF) 3D printing using liquid material such as stereolithography digital light processing (DLP), (multi-jet modeling (MJM) or film transfer imaging method known.

The object of the present invention is to specify a device for the initial shaping of a 3D body with which high-quality 3D bodies can be formed with the least possible expenditure of energy and the least possible time required.

This object is achieved with the features of the protection claim 1. Advantageous developments of the invention are specified in the subclaims. All combinations of at least two features specified in the description, the claims and / or the figures also fall within the scope of the invention. For specified ranges of values, values lying within the stated limits should also be disclosed as limit values and be able to be used in any combination.

The basic idea of the present invention is to arrange a fusible, in particular pulverulent, and / or curable, in particular fluid, material in a matrix space and then to fuse the fusible and / or curable material to the 3D body defining matrix points within the matrix space with ultrasonic waves and / or cure.

An aspect according to the invention thus consists, in particular, in arranging the entire fusible and / or curable material from which the 3D body is formed, before being subjected to fusion and / or curing in a matrix space. As a result, the production of the 3D body can be significantly accelerated, in particular in comparison to the previously known layer method.

A further aspect of the present invention consists, in particular, of the matrix points defining the 3D body from outside the matrix space or from outside the outer contour of the 3D body or from outside a housing defining the matrix space for accommodating the fusible and / or curable material, in particular software-computed, to apply prescribed sequence, in particular starting from a matrix point remote from the ultrasound transmitters.

According to a further advantageous aspect of the present invention, ultrasound waves of at least two, preferably at least four, more preferably at least eight, more preferably at least 16, even more preferably at least 32, even more preferably at least 64 ultrasound transmitters are superimposed in such a way that in the respective acted upon matrix point Energy maximum is generated, which is suitable for fusing and / or curing of the fusible and / or curable material in the region of the matrix point. For this purpose, in particular a phased array arrangement of the ultrasonic generator is suitable.

• – Phasenverschiebung der Ultraschallgeber zueinander,
• – Frequenz, Amplitude, Modulation und/oder Phasenlänge der Ultraschallwellen jedes Ultraschallgebers,
• – Abarbeitung der Sequenz der Beaufschlagung der Matrixpunkte,
• – Vorheizen des fusionierbaren und/oder aushärtbaren Materials,
• – Verdichtung des fusionierbaren, pulverförmigen Materials, vor und/oder während der Beaufschlagung,
• – Fokussierung der Ultraschallwellen der Ultraschallgeber, insbesondere durch Überlagerung (Summe der Ultraschallwellen),
• – Übersetzung (insbesondere durch softwaregestützte Berechnung) der dreidimensionalen Geometriedaten des 3D-Körpers in abzuarbeitende Matrixpunkte,
• – Steuerung von Ultraschallimpulsen, insbesondere nach dem Phased-Array-Prinzip,
• – Strahlungsrichtung der Ultraschallgeber, insbesondere durch, vorzugsweise gemeinsame, Bewegung der Ultraschallgeber oder Gruppen von Ultraschallgebern,
• – Steuerung eines regelbaren Phasenschiebers.

In a development of the present invention, in particular a control device is provided, which assumes at least one or more of the following control tasks:

• Phase shift of the ultrasonic transmitters to each other,
• The frequency, amplitude, modulation and / or phase length of the ultrasonic waves of each ultrasound generator,
• Processing the sequence of application of the matrix points,
• Preheating the fusible and / or hardenable material,
• - compression of the fusible, powdered material, before and / or during loading,
• Focusing of the ultrasound waves of the ultrasound transmitters, in particular by superposition (sum of the ultrasound waves),
• - Translation (in particular by software-based calculation) of the three-dimensional geometry data of the 3D body in matrix points to be processed,
• Control of ultrasonic pulses, in particular according to the phased array principle,
• Radiation direction of the ultrasound transmitters, in particular by, preferably common, movement of the ultrasound transmitters or groups of ultrasound transmitters,
• - Control of a controllable phase shifter.

The control device can in particular take over further control tasks listed below.

In other words, an aspect according to the invention consists, in particular, of effecting selective application of ultrasound waves for curing or fusing selectively in the interior of a fusible and / or curable material arranged in a matrix space.

The arrangement of the fusible and / or curable material in a matrix space takes place in particular in a, preferably closable, housing, which defines in particular the matrix space by means of coordinates. X, Y and Z coordinates may preferably form a Cartesian coordinate system or a polar coordinate system. The coordinate system correlates in particular with the three-dimensional geometry data of the 3D body or can be correlated with it and used in particular for vector calculations.

According to an advantageous embodiment, an X-Y plane formed by X and Y coordinates is arranged parallel to the position of the ultrasound generator. The Z-coordinate in this case maps the distance of the Matix points or the focus point to the ultrasound transmitters.

A focusing of the ultrasound waves at the matrix points takes place in particular by generating an energy maximum in the region of the matrix point, preferably by generating an interference of the ultrasound waves of the at least two ultrasound emitters in the region of the matrix point. As a result of the locally generated energy input in at least partially surrounded by unfused and / or uncured, fusible and / or curable material area of the matrix point, all matrix points, in particular without movement of the ultrasound generator or a group of ultrasound transmitters or all ultrasound transmitters relative to the matrix space, sequentially be charged.

The phased array principle is a directed emission of ultrasonic pulses from a probe. A directional influence is made by means of a group radiator. This group emitter is preferably located in a common encoder housing and has in particular several, preferably more than four, more preferably more than eight, more preferably more than 16, even more preferably more than 32, even more preferably more than 64 individual emitters. The individual radiators preferably work with piezoelectric elements or even more preferably with capacitive ultrasonic transmitters, in particular capacitive micromachined ultrasonic transducers (CMUT).

According to a preferred embodiment of the invention, at least one of the ultrasound transmitters, preferably all ultrasound transmitters, is capable not only of transmitting ultrasonic waves but also of receiving them. As a result, existing in the fusible and / or curable material structures (for example, additional components, metal inserts, electronics, etc.), in particular before the application and / or determination of the matrix points are detected. In the case of a hardenable material, partial introduction of structures into the curable material may occur to form support structures.

In accordance with a further advantageous embodiment of the present invention, the application begins with matrix points farther from the ultrasound transmitters and ends with matrix points located closer to the ultrasound transmitters. Thus, the loading of the matrix points is controlled sequentially such that preferably at no time of the application between a not yet fused and / or cured matrix point and the ultrasound transmitters an already applied matrix point is arranged. The advantage of this approach is that the encoder housing relative to the housing for receiving the fusible and / or curable material does not have to be moved. Accordingly, the transmitter housing can in particular be arranged or arranged rigidly on the housing for accommodating the fusible and / or curable material.

An advantageous aspect of the present invention is that the fusible and / or curable material does not have to be moved during the application of the fusible and / or curable material and formation of all matrix points, in particular in a continuous application step, until the end of the loading.

In a further development, at least predominantly, preferably exclusively, adjacent matrix points are acted upon in succession (sequential). The loading is thus carried out in particular along a meandering path of Matrix points, wherein a change of direction and focusing of the sound beam, in particular exclusively, by controlling the ultrasonic transducer, preferably by means of a controllable phase shifter takes place.

Alternatively, several, in particular adjacent, matrix points can be acted upon in parallel / simultaneously, in particular by forming groups of at least two ultrasound transmitters each.

Distances between adjacent matrix points are preferably selected such that the fusible and / or curable material arranged between the adjacent matrix points is also completely fused and / or cured by the application of the adjacent matrix points.

The local energy input preferably takes place in that the ultrasound waves are focused in the respectively applied matrix point and / or form an interference which is specific in particular for the fusible and / or curable material. Preference is given here to the phased array principle.

A, in particular independent aspect of the present invention is to control the ultrasound generator so that the respective acted matrix point is in the focus of the ultrasonic waves or at the superposition of the ultrasonic waves. It is crucial, in particular, that a constructive interference is generated in the matrix point. The energy thus induced causes the material to fuse or harden around the (infinitesimally small) matrix point, with the fused or hardened volume depending on the parameters of the ultrasound transmitters and their location and drive. The energy needed to fuse or cure the material depends on the type of material and additional external factors such as temperature and pressure in the matrix space.

In particular, the geometric shape and size (volume) of the focus volume formed with constructive interference can also be influenced. As a result, the volume in which the matrix point is fused and / or cured can be minimized. Preferably, the volume is less than 1 cm ³ , more preferably less than 1 mm ³ , even more preferably less than 500 μm ³ , even more preferably less than 200 μm ³ .

In order to avoid air entrapment, it is preferred according to an embodiment of the present invention, if the fusible material is compacted before and / or during the application.

As far as the ultrasound transmitters are combined in a transmitter housing, which is arranged on a, in particular an opening for the passage of the ultrasonic waves, having wall of the housing, the device can be realized to save space. A further advantage is that the arrangement of the ultrasound transmitters relative to the matrix shape and relative to the coordinates of the matrix points is fixed and thus preferably only a single calibration of the ultrasound transmitters is necessary.

In order to minimize the energy required by the ultrasonic radiation for fusing and / or curing the fusible and / or curable material in the respective matrix point, according to a preferred embodiment of the invention, a heating device for heating / tempering the fusible and / or curable material arranged in the housing provided an admission temperature. The loading temperature is preferably below a melting temperature of the fusible material or below an activation temperature of the curable material, in particular in a temperature range of at least 1 ° Celsius below at most 100 ° Celsius below the melting temperature or the activation temperature, preferably at least 10 ° Celsius below and 50 ° maximum Celsius below the melting temperature or the activation temperature.

The pressurization for compression of the fusible material is realized according to an advantageous embodiment of the invention by a pressurizing device.

• – keine Bewegung des fusionierbaren und/oder aushärtbaren Materials während der, vorzugsweise kontinuierlichen, Beaufschlagung/Sinterung des fusionierbaren und/oder aushärtbaren Materials. Hieraus ergibt sich eine höhere Geschwindigkeit, Genauigkeit und geringere Fehleranfälligkeit,
• – keine Fremdbauteile wie Rakel oder eine Höhenverstellung am 3D-Körper, da der 3D-Körper von dem nicht beaufschlagten fusionierbaren und/oder aushärtbaren Material bis zur Fertigstellung gehalten wird und das fusionierbare und/oder aushärtbaren Material anschließend auf einfache Weise entfernbar ist,
• – weitgehende bis vollständige Freiheit bei der Form des 3D-Körpers,
• – keine Supportstrukturen notwendig,
• – keine Inertgas- und/oder Druckluftversorgung notwendig,
• – keine wartungsanfällige Optik notwendig,
• – zusätzlich Bauteile wie Materialeinsätze, Elektronik etc. können mitverarbeitet werden, soweit diese bis zur Schmelztemperatur oder Aktivierungstemperatur temperaturbeständig sind,
• – ein Materialgradient ist realisierbar, insbesondere durch Anordnung verschiedener Pulversorten im Matrixraum.

The above-described measures in particular the following advantages or advantageous embodiments are achieved:

• No movement of the fusible and / or curable material during the, preferably continuous, charging / sintering of the fusible and / or curable material. This results in a higher speed, accuracy and lower susceptibility to errors,
• No foreign components such as squeegees or height adjustment on the 3D body, since the 3D body is held by the unimpacted fusible and / or curable material to completion and the fusible and / or curable material is then easily removable,
• - extensive to complete freedom in the shape of the 3D body,
• - no support structures necessary,
• - no inert gas and / or compressed air supply necessary,
• - no maintenance-prone optics necessary,
• - In addition, components such as material inserts, electronics etc. can be co-processed, as far as they are temperature-resistant up to the melting temperature or activation temperature,
• - A material gradient can be realized, in particular by arranging different powder types in the matrix space.

According to an advantageous embodiment of the invention, at least one ultrasound transmitter, preferably all ultrasound transmitters or the transmitter housing, is arranged within the housing and thus within the housing and / or within the matrix space. As a result, a possible phase boundary on a housing wall is avoided. Alternatively, an opening in the housing wall in the region of the ultrasound generator can also be provided for this purpose.

According to a further advantageous embodiment of the invention, a plurality of groups of ultrasound transmitters or a plurality of transmitter housings are arranged or can be arranged on different, in particular opposite, sides of the housing. As a result, the construction volume and / or the speed of Urformung be increased.

• – Kunststoff-, Keramik- und/oder Metallpulver, insbesondere aus Mikro- oder Nanopartikeln, vorzugsweise Polyamid PA, Polypropylen PP und/oder
• – Fluide, insbesondere Harze oder Polymere.

As fusible and / or curable material in particular the following materials or classes of materials in question:

• - Plastic, ceramic and / or metal powder, in particular of micro or nanoparticles, preferably polyamide PA, polypropylene PP and / or
• - Fluids, in particular resins or polymers.

The treatment temperature or preheating temperature is in particular between 100 ° Celsius and 500 ° Celsius, preferably between 150 ° Celsius and 300 ° Celsius, more preferably between 150 ° Celsius and 160 ° Celsius, in particular in combination with polypropylene PP. The melting temperature of polypropylene PP is 165 ° Celsius.

Preferably, the housing is formed thermally insulated in order to allow the most constant possible application temperature and to consume as little energy.

• – Vorheizen auf die Beaufschlagungstemperatur für 10 Minuten bis 60 Minuten, vorzugsweise für 20 bis 40 Minuten,
• – Beaufschlagung mit Ultraschall für 10 Sekunden bis 10 Minuten, vorzugsweise 30 Sekunden bis 5 Minuten, noch bevorzugter 30 Sekunden bis 2 Minuten,
• – Abkühlen für 10 Minuten bis 2 Stunden, vorzugsweise 30 Minuten bis 90 Minuten, vorzugsweise 50 Minuten bis 70 Minuten.

In the case of a size of the matrix space of 10 cm × 10 cm × 10 cm, the following is conceivable according to the invention as a time sequence:

• Preheating to the loading temperature for 10 minutes to 60 minutes, preferably for 20 to 40 minutes,
• Ultrasonication for 10 seconds to 10 minutes, preferably 30 seconds to 5 minutes, more preferably 30 seconds to 2 minutes,
• Cooling for 10 minutes to 2 hours, preferably 30 minutes to 90 minutes, preferably 50 minutes to 70 minutes.

A powder compaction can be carried out in particular at a pressure between 2 bar and 20 bar, preferably between 5 bar and 15 bar, more preferably between 8 bar and 12 bar.

A focusing distance of the ultrasound transmitters to the matrix point lies in particular between 5 mm and 500 mm, more preferably between 10 mm and 200 mm, even more preferably between 10 mm and 100 mm.

A particularly preferred energy input per volume when applying the matrix points according to the invention is between 10 mJ / mm ³ and 30,000 mJ / mm ³ , preferably between 20 mJ / mm ³ and 20,000 mJ / mm ³ , more preferably between 30 mJ / mm ³ and 10,000 mJ / mm ³ . The necessary energy input depends very much on the material and on the energy difference to be made.

According to an advantageous embodiment of the invention, groups of matrix points are formed, which, in particular from different directions, are acted upon in each case by at least two ultrasound transmitters. Preferably, the 3D body is divided into a corresponding number of sub-bodies corresponding to the groups of matrix points.

Insofar as process features have been disclosed, they should also be disclosed as device features and vice versa.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. This shows in:

1a FIG. 2: a schematic perspective view of an embodiment of a device according to the invention, FIG.

1b FIG. 2 is a schematic representation of a first method step of an embodiment of the method according to the invention, FIG.

1c FIG. 2 is a schematic representation of a second method step of the embodiment according to FIG 1b .

1d a schematic representation of one with the embodiment according to 1b and 1c original 3D body,

2a a schematic plan view of a first embodiment of an array of ultrasonic generators,

2 B a schematic plan view of a second embodiment of an array of ultrasonic generators and

2c a schematic plan view of a third embodiment of an array of ultrasonic generators.

1 shows a housing 1 that is a matrix space 2 surrounds and defines. On a side wall of the housing 1 is a transmitter housing 3 arranged and preferably fixable.

In the encoder housing 3 is a variety (s) of ultrasound transmitters 3.1 . 3.2 to 3.n arranged (see 2a . 2 B and 2c ), the ultrasonic waves in the direction of the matrix space 2 and in the matrix space 2 can radiate into it. The ultrasonic waves of the ultrasonic generator 3.1 . 3.2 to 3.n are controlled by a controller (not shown). The control device is preferably within the transmitter housing 3 arranged.

In the in 1b shown process step is a fusible, powdery material 4 in the matrix space 2 arranged and optionally compressed and / or preheated to an admission temperature. The application temperature is in particular below a melting or sintering temperature of the fusible material.

In the in 1c the process step shown is the fusible material 4 in a matrix point 5 with a directed and focused ultrasound beam 6 applied. The ultrasound beam 6 becomes in the matrix point 5 concentrated or focused (superposition), so that an energy maximum of the superimposed ultrasound beams of the ultrasound generator 3.1 . 3.2 to 3.n into the matrix point 5 is produced. The energy input is sufficient to the fusible material 4 in the area of the matrix point 5 to melt / sinter.

One after the other becomes a multiplicity of matrix points 5 according to the in 1c shown process step applied with ultrasonic beams, wherein the matrix points 5 a 3D body 7 Define after applying all the 3D body 7 defining matrix points 5 is completed.

That's the 3D body 7 surrounding fusible material 4 is not subjected to an energy sufficient for sintering / melting, so that the remaining fusible material 4 can be used for a further melting / sintering process.

In the embodiment according to 2a are 32, in particular identically formed, ultrasonic generator 3.1 to 3:32 as a group of annular ultrasonic generators 3.1 to 3:32 merged in an XY plane, which are each controlled separately by a control device. By controlling the from the ultrasonic generators 3.1 to 3:32 output ultrasonic waves according to the phased array principle can be formed at an adjustable distance in the Z direction (orthogonal to the XY plane) constructive interference (focusing). The constructive interference becomes the fusible material 4 locally fused at this point (here: melted), while the other waves destructively interfere and thus cause no fusion.

The position of the focus can be adjusted not only in the Z direction by the controller, but also in parallel with the XY plane. Thus, almost any point in the emission or beam path of the group of ultrasonic generators 3.1 to 3:32 be controlled, in particular without a movement of the ultrasonic transducer 3.1 to 3:32 and / or the encoder housing 3 ,

The focusing is controlled in particular so that the ultrasonic waves in the respective matrix point 5 maximum interfere (superposition) and the interference energy thus at the respective matrix point 5 is maximum. In particular, the focusing and / or superposition of the ultrasonic waves is controlled such that the interference (energy) with distance to the matrix point 5 decreases as quickly as possible. Thus, the smallest possible volume becomes around the matrix point 5 fused and / or cured.

Alternative arrangements are in the 2 B and 2c being shown in the 2 B 25, in particular identically designed and arranged as a rectangular grid, the ultrasonic generator and in the 2c 30 concave curved extending to the plane of the drawing, ultrasonic emitters are included.

LIST OF REFERENCE NUMBERS

1

casing

2

matrix space

3

encoder housing

3.1, 3.2 to 3.n

ultrasonic generator

4

fusible and / or curable material

5

matrix point

6

ultrasonic beam

7

3D body

Claims (4)

Device for forming a 3D body ( 7 ) of a fusible and / or curable powdery material ( 4 ) with: - a matrix space ( 2 ) with a matrix consisting of X coordinates, Y coordinates and Z coordinates ( 1 ) for receiving the fusible and / or hardenable material ( 4 ), - a control device for fixing the 3D body ( 7 ), each having an X-coordinate, Y-coordinate and Z-coordinate matrix points ( 5 ) in the matrix space ( 2 ), - at least two ultrasound transmitters ( 3.1 . 3.2 to 3.n ) for charging the fusible and / or curable material ( 4 ) at the matrix points ( 5 ) with superimposed and at least partially sequential on the matrix points ( 5 ) directed ultrasonic waves for fusing and / or curing of the fusible and / or curable material ( 4 ) and original shaping of the 3D body ( 7 ) in the housing ( 1 ). Apparatus according to claim 1, wherein the ultrasound transmitters ( 3.1 . 3.2 to 3.n ) in a transmitter housing ( 3 ) are combined, which at one, in particular an opening for the passage of the ultrasonic waves having, wall of the housing ( 1 ) is arranged. Apparatus according to claim 1 or 2, comprising a heating device for heating in the housing ( 1 ) arranged fusible and / or curable material ( 4 ) to an admission temperature. Device according to one of claims 1 to 3, which comprises a pressurizing device for compressing the pulverulent, fusible material ( 4 ) before and / or during the application of the pulverulent, fusible material ( 4 ) with ultrasonic waves.

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