System for producing an object by means of additive manufacturing

Abstract

A system for producing an object by means of additive manufacturing including an apparatus, having a storage container for storing powdered material that can be solidified, and a process chamber fluidly connected to the storage container and arranged for receiving at least a part of the powdered material for forming a bath of material within the process chamber. Furthermore, a structure is provided for positioning the object in relation to the surface level of the bath of material. The apparatus also includes a solidifying device for solidifying a layer of the bath of material. A supply device is provided, having a supply container for storing a supply of powdered material that can be solidified, wherein the supply device is fluidly connected, or at least connectable, to the storage container, and wherein the apparatus is arranged for transferring powdered material between the supply container and the storage container.

Claims

1. A system for producing an object by an additive manufacturing process, comprising: an apparatus comprising: a storage container configured to store powdered material; a process chamber fluidly coupled to the storage container, the process chamber configured to receive powdered material from the storage container to form a bath of powdered material within the process chamber; a structure configured to position the object relative to a surface level of the bath of powdered material; a radiation device configured to sinter at least a part of a layer of the bath of powdered material; and an extraction device fluidly coupled to the process chamber, the extraction device configured to extract powdered material from the process chamber; a supply device fluidly coupled to each of the storage container and the extraction device, the supply device including a supply container configured to store a new supply of powdered material to be supplied to the storage container, wherein the supply device is releaseably coupled to the apparatus; and a transfer device configured to transfer powdered material between the supply container and the storage container.

2. The system according to claim 1, further comprising a flushing device configured to flush a fluid coupling between the supply container and the storage container with an inert gas including at least one of argon or nitrogen.

3. The system according to claim 1, wherein the storage container is an integral part of the apparatus.

4. The system according to claim 1, wherein, in a fluidly coupled state of the of the supply device, the supply container and the process chamber are sealed from an external environment.

5. The system according to claim 1, wherein the extraction device includes a blower configured to induce a gaseous flow in the process chamber to facilitate extraction.

6. The system according to claim 1, wherein the transfer device is a pneumatic transfer device.

7. The system according to claim 6, wherein the pneumatic transfer device includes a pump and fluid lines fluidly coupling the supply container to the apparatus.

8. The system according to claim 7, wherein the pump is attached to or positioned within the supply device.

9. The system according to claim 1, further comprising a filter fluidly coupled between the supply container and the apparatus.

10. The system according to claim 9, wherein the filer is a cyclone filter.

11. The system according to claim 9, wherein the filter is positioned in the supply device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will be described in the following in connection with the Figures. In the Figures:

(2) FIG. 1 shows a schematic overview of a first embodiment of a system according to the present invention for additive manufacturing an object;

(3) FIG. 2 shows a schematic overview of a second embodiment of the system according to the present invention;

(4) FIG. 3 shows a schematic overview of a third embodiment of the system according to the present invention;

(5) FIG. 4 shows a schematic overview of a fourth embodiment of the system according to the present invention;

(6) FIG. 5 shows a detailed overview of a fifth embodiment of the system according to the invention.

DETAILED DESCRIPTION

(7) FIG. 1 shows an overview of a system 1 for producing an object 2 by means of additive manufacturing. The system comprises an apparatus 19 that is built from several frame parts 11, 12, 13, 14. The apparatus 19 comprises a process chamber 3 for receiving a bath of material 4 which can be solidified. In a lower frame part 11, a shaft 50 is formed, wherein a support 5 is provided for positioning the object 2 in relation to the surface level L of the bath of material 4. The support 5 is movably provided in the shaft 50, such that after solidifying at least a part of a layer, the support 5 may be lowered, and a further layer of material may be solidified on top of the part of the object 2 already formed. In a top part 13 of the apparatus 19, a solidifying device 7 is provided for solidifying a selective part of the material. In the embodiment shown, the solidifying device 7 is a laser device, which is arranged for producing electromagnetic radiation in the form of laser light, in order to melt a powdered material provided on the support, which then, after cooling forms a solidified part of the object 2 to be produced. However, the invention is not limited to the type of solidifying device 7. As can be seen, the electromagnetic radiation 71 emitted by the laser device 7 is deflected by means of a deflector unit 74, which uses a rotatable optical element 75 to direct the emitted radiation 71 towards the surface L of the layer of material 4. Depending on the position of the deflector unit 74, radiation may be emitted, as an example, according to rays 72, 73.

(8) On the left hand side of FIG. 1, powder supply means 6 are provided. These powder supply means 6 comprise a storage container 61 for storing powdered material that can be solidified. This storage container 61 is fluidly connected, via a powder supply means 16, such as a nozzle or a (rotary) valve, to the process chamber 3. Connected to the storage container 61 is a supply device 8. This movable supply device 8 has a supply container 18 for storing a supply of powdered material that can be solidified. As can be seen, the supply device 8 is fluidly connected to the storage container by means of line 86. The system 1 according to the invention is arranged for transferring powdered material between the supply container 18 and the apparatus 19, and in particular between the supply container 18 and the storage container 61. This may mean that the transfer takes place from the supply container 18 to the storage container 61, and/or from the storage container 61 to the supply container 18. Transfer means, such as fluid lines and one or more pumps, may be provided to this end. In the embodiment shown in FIG. 1, the supply device 8 is releasably connectable to the storage container 61. Suitable connecting means may be provided to this end, with which the supply device 8 may be connected and/or reconnected to the storage container 61. The supply device 8 is movable due to the fact that a number of wheel elements 20 are provided.

(9) With the supply device according to the invention, it is relatively easy to refill the storage container 61, or to empty it if needed. Filling and/or emptying may be done relatively quickly, and may even be performed when the solidifying device 7 of the apparatus 19 is active. Filling of the supply device 8 may for instance be performed at a location distant from the apparatus 19, and may thus be performed under specific and controlled conditions, ensuring that the quality of the powdered material reaches a predetermined standard. The subsequent filling may then be performed relatively quickly.

(10) In an embodiment, the supply device 8 is provided next to the apparatus 19, and connected by means of the connecting means 86 to the apparatus. Once said supply device 8 is connected to the apparatus 19, powdered material may be transferred between the supply container 18 and the apparatus 19.

(11) Additionally flushing means may be provided for flushing the connection means, in particular with an inert gas such as argon or nitrogen. A gas supply 117 (see FIG. 5) may be present in the device 8 for flushing the connection means and conduits. Alternatively, the gas supply may be present in the apparatus 19 itself (see FIGS. 3 and 4). Thus, the connection means may be flushed, in particular with an inert aas such as argon or nitrogen. In any event, the use of an inert gas for flushing the lines and conduits increases the quality of the powder supply, as oxygen uptake by the powder will be prevented. Additionally, this increases the safety of the system, as the risk of explosion is dramatically reduced when oxygen is replaced by inert gases.

(12) Also, it will be possible to increase the quality of the powdered material in the storage container 61 when the step is performed of mixing powdered material in the storage container 61 with powdered material in the supply container 18. To this end, the powdered material in the storage container 61 may be extracted to the supply container 18, where mixing takes place, whereafter the mixed powder may be transferred back to the storage container 61.

(13) As already stated, the use of the storage device 8 according to the invention allows the step of supplying powdered material to the storage container 61 to be performed during use of the solidifying device 7.

(14) FIG. 2 shows a further embodiment of the system 1 with the apparatus 19 according to the invention. In this embodiment two storage containers 61, 62 are provided. Both storage containers 61, 62 are connected to the powder supply nozzle 16. Powder from both containers 61, 62 may thus be provided to the process chamber 3. The supply device 8 is connected, via lines 86 and 86′, to both storage containers 61, 62. Powder may be supplied to both containers 61, 62, or may be extracted from both containers 61, 62. Alternatively, powder may be supplied to the top most container 62, and may be extracted from the bottom container 61.

(15) FIG. 3 shows a further embodiment of the system 1 according to the invention. In this embodiment, the apparatus 19 shown further comprises an extraction device 9 fluidly connected to the process chamber 3 and arranged for extracting material 4 out of the process chamber. The extraction device 9 may be a pump. The supply device 8 is fluidly connected to the extraction device 9, and thus to the process chamber 3, by means of extraction line 89. Thus, when the extraction device 9 is activated, excess powder from the process chamber 3 may be transferred to the supply device 8 for further use.

(16) FIG. 4 shows a further embodiment of the system 1 according to the invention. This embodiment is similar to the embodiment of FIG. 3, with the following additions. Here, the apparatus 19 is provided with blowing means 10 on the opposite side of the process chamber 3 for inducing a gaseous flow in the process chamber 3 effecting the material to be extracted. Further blowing means may be provided as well, for more effectively influencing the powdered material in the process chamber 3. The blow nozzle 10 is connected via lines 82 to a control unit 94. The extraction device 9 is connected via line 84 to the control unit 94. The control unit 94 may be used to start and/or stop the blowing nozzle 10 (or nozzles). The extraction device 9, for instance in the form of a suction device 9, is also connected to this control unit 94, such that operation thereof may be synchronized. It is, however, conceivable that the extraction device 9 is provided with a separate control unit.

(17) FIG. 4 further shows that the extraction device 9 is connected to the supply device 8 by means of extraction line 89. A storage container 61 is provided in the lower frame part 11 of the apparatus 19, and is also connected to the extraction device 9. The storage container 61 is also connected to the supply device 8. The storage container 61 is fluidly connected to the process chamber 3, such that a layer of material may be deposited in the process chamber 3. Details of this fluid connection are not shown in FIG. 4, but these details have already been described with reference to FIG. 1.

(18) FIG. 5 shows a further embodiment of the system 1 according to the invention, having two additional nozzles 92, 93, which may be movable nozzles 92, 93, and in which in particular details of the apparatus 19 downstream of the extraction device 9 are shown. The extraction device 9 comprises an extraction tube 121 comprising a pumping unit (shown as one unit 121), wherein an inlet opening of the extraction tube 121 is positioned within the process chamber 3. Furthermore, the extraction device 9 is fluidly connected, via line 87, to a filter unit 101, in particular a cyclone filter unit 101, which may be used to filter the extracted gaseous flow containing the material extracted from the process chamber. For instance, this allows powdered material contained in the flow to be filtered and collected for further usage. The cyclone filter unit 101 is connected, via line 111, to a first storage container 103 or collector, for collecting powdered material filtered by the filter unit 101. The gaseous flow may, after having passed the filter unit 101, be exhausted from the apparatus 19 by means of exhaust tube 114 and exhaust outlet 104. In this way, the gaseous flow may be vented through the exhaust tube 114 and outlet 104. In a preferred embodiment, the exhaust tube 114 is connected to the blowing means 10, such that the filtered gas flow may once again be introduced into the process chamber.

(19) The first storage container 103 is connected, via line 112, to a second storage container 102, provided above the first storage container 103. Material collected in the first storage container 103 may be transferred via line 112 to the second storage container 102, for later use. An overflow line 113 is provided between the second storage container 102 and the filter unit 101, which may be used to filter the extracted material a plurality of times, by re-feeding said material back to the filter unit a number of times, for instance.

(20) Thus, the extraction device 9 may be connected to one or more storage container 103, 102 for holding material extracted from the process chamber. This material may be re-used, for instance for laying down a further layer of material to be solidified.

(21) Furthermore, the system 1 comprises a supply device 8 that is connected to the first storage container 103 and the second storage container 102, via lines 86 and 88, respectively. The supply device 8 comprises a supply container 118, and a filter unit 119 provided upstream thereof. A pump unit (not shown) may be used to transfer powdered material from the supply device 118 to the first storage container 103. Additionally, or alternatively, powdered material may be extracted from the second storage container 102 to the supply container 118. The filter unit 119 may be used to further filter the powdered material coming from the second storage container 102.

(22) It will be clear to those skilled in the art, that the invention is described above by means of several embodiments. However, the invention is not limited to these embodiments. Combinations of individual parts of the several embodiments are conceivable. The desired protection is defined by the appended claims.