Method for producing three-dimensional objects by successively solidifying layers of a powdered build-up material using electromagnetic radiation
The innovative build chamber design with a partially open underside and a support device that extends downwards during construction addresses the need for continuous production in additive manufacturing, enabling uninterrupted production of multiple parts.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- CONCEPT LASER
- Filing Date
- 2011-12-22
- Publication Date
- 2026-06-11
AI Technical Summary
Existing additive manufacturing methods, such as SLM and SLS, require process interruptions to remove completed objects from the build chamber, limiting continuous production of multiple parts.
A build chamber design with a partially open underside and a support device that extends downwards during the construction process, allowing continuous production of multiple objects without interrupting the process, using a guide and motor-driven elements to facilitate the removal of completed parts.
Enables continuous construction of multiple parts without stopping the process, enhancing production efficiency by allowing seamless removal of objects from the chamber.
Smart Images
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Abstract
Description
[0001] The invention relates to a method for producing three-dimensional objects by successively solidifying layers of a powdered build-up material that can be solidified by means of electromagnetic radiation, in particular bundled radiation such as laser radiation or electron radiation, with the further features of claim 1.
[0002] Devices for carrying out processes of this type are generally referred to as laser sintering (SLS) or laser melting (SLM) machines and typically include a support structure for holding the object to be manufactured. A coating device serves to apply powdered build material to the support structure or to a previously formed and at least partially solidified layer. An irradiation device serves to solidify the layers of build material at the points corresponding to the respective cross-section of the object. The support structure is arranged within the build chamber so that it can be adjusted vertically.The radiation is guided through a scanner device that is suitable for directing the laser beam, depending on construction data, to areas of the powder layer to be solidified and for carrying out the sintering process or a melting process there, which leads to a solidification of the layer and a bond with underlying layers of the building material.
[0003] In conventional SLM or SLS devices, after completion of a build process, the support structure is usually moved to an upper position and the unsolidified powder is removed from the build chamber, so that the manufactured object is exposed and can be removed from the build chamber upwards or forwards. It is also already known to solidify the first layer(s) of the build material on a build plate, which can be attached to the support structure before the start of the build process and is removed from the overall device together with the object after completion of the build process.
[0004] EP 2 289 652 A1 teaches a method for manufacturing products with individual geometry comprising the steps of: - manufacturing multiple products on the surface of a substrate plate by selective curing, wherein the first and each subsequent substrate plate segment is detachably connected to each other or to a base support and is raised and lowered in a vertical direction by means of a lifting device during the manufacturing process, and the lifting and lowering movement of the substrate plate segments is independent of each other.
[0005] DE 10 2009 056 689 A1 describes a coater for a system for the layer-by-layer construction of a molded body by forming superimposed layers of a building material and by selectively solidifying a partial area of the respective building material layer before forming the next layer, wherein a coater has a feed container which is arranged above the metering chute and the feed container is pivotably connected to a coater support, so that the feed container can be pivoted about a pivot axis which is parallel to the longitudinal axes of the metering chute and the feed container into a cleaning position in which the discharge opening of the feed container and the feed opening of the metering chute are exposed.
[0006] Further state of the art is known from the documents DE 10 2007 048 385 B3, DE 10 2007 033 434 A1, DE 10 2009 015 130 A1, EP 2 289 462 A1 and the Wikipedia article: “Selective Laser Sintering” (URL: https: / / de.wikipedia.org / w / index.php?title=Selektives_Lasersintern&oldid=908487 33).
[0007] The invention is based on the objective of further developing a method of the aforementioned type with the features of the preamble of claim 1 in such a way that a continuous construction process can be carried out with it, i.e. a large number of parts of the same or different types can be produced successively without interrupting the actual construction process, wherein manufactured objects should be removable from the construction chamber while the construction process is still running on other objects.
[0008] This problem is solved by the features of claim 1.
[0009] The core of the invention according to claim 1 is considered to be the design of the build chamber as being at least partially open on its underside by means of a removal opening. The support device is designed such that it can be extended downwards through the removal opening together with the object(s) built on it, particularly synchronously with the build process. The objects are either arranged in an additively manufactured housing that is essentially rod-shaped, or the objects themselves form an essentially rod-shaped body.Either the housing containing the actual objects, or the rod-like mold body itself, is continuously extended downwards from the build-up device along with the support structure. It essentially grows downwards during the build process and can then be removed. The height adjustment of the build plane relative to the coating plane is handled by a guide in the area of the removal opening. The actual support structure is the first component to exit the build-up device downwards and is initially held either by the additively manufactured housings, which comprise stacked cells for holding the objects, or by the rod-like mold body itself. Several separate objects, particularly small objects such as jewelry components, mold parts for injection molds, dental components, crowns, and the like, can be arranged in individual chambers of the housing, separated from each other by lid-like partitions.The lid-like partitions are held together by lateral, tube-like housing sections. These housing sections need not necessarily be closed; their walls only need to be suitable for providing a certain degree of guidance within the dispensing opening. Advantageously, the outer contour of the housing-forming wall sections of the housing or the rod-like molded body corresponds to the outer contour of the support device, which in turn is adapted to the inner contour of the dispensing opening. The support device and the object parts or housing parts mounted on it thus form a column that extends continuously and synchronously downwards from the device, synchronously with the layer-by-layer production of the component(s). This column is guided within the dispensing opening by a motor or by other guide or motor drive elements to carry out the build process.
[0010] Advantageously, the wall sections or molded body sections are provided with predetermined breaking points or separation points, so that object sections or housing sections protruding downwards from the build chamber can be easily broken off. To facilitate this, clamping elements can be provided in the area of the removal opening. The removal opening advantageously has a cylindrical or other cross-section that enables precise guidance of the component strand growing out of the build chamber.
[0011] The motor-driven element, which ensures both the layer-conforming lowering of the build platform and the downward feed, can, for example, be designed as one or more drive rollers that act on the side walls of the component string. The guide elements are advantageously designed to be powder-tight so that building material cannot fall out of the build chamber.
[0012] The invention is explained in more detail with reference to exemplary embodiments shown in the drawings. These show: Fig. 1: a schematic representation of a device according to the invention; Fig. 2: a schematic representation of the carrying device with objects mounted on it, which are arranged in additively constructed housing sections; Fig. 3: a schematic representation of the carrying device with a rod-like shaped body built on it.
[0013] The device 1 is designed for the production of three-dimensional objects 7a, 7b, 7c by successively solidifying layers of a powdered build-up material that can be solidified by electromagnetic radiation such as laser radiation, in particular by a SLM or SLS process. The device 1 includes a support device 2 for carrying the object(s). Furthermore, a coating device 3 is provided with which layers of the powdered build-up material can be applied to the support device 2 or to a previously formed layer. For solidifying the layers, which are designed as planar layers, an irradiation device 15 in the form of a laser is used, wherein the output radiation 6 is guided over a scanner, which is controlled by a computer 8 such that the focus 9 of the output radiation 6 densifies the powder layer only at those points that are to subsequently form the component.
[0014] The support device 2 is arranged in a build chamber 10, the walls of which, in this embodiment, closely enclose the support device, which has the overall shape of a piston, to prevent powder material arranged on the surface 12 of the support device 2 from falling out through a dispensing opening 13 in the area of the underside 14 of the build chamber 10. The support device 2 is designed such that it can be extended downwards through the dispensing opening 13, together with the object(s) (component) applied to it, synchronously with the progress of the layer-by-layer build process. The objects 7a, 7b, 7c are arranged in an additively manufactured housing.
[0015] Several separate objects 7a, 7b, 7c can be additively built up on top of each other on the support device 2, being separated from one another by lid-like intermediate floors 34 of the housing. The objects 7a, 7b, 7c are arranged within wall sections of the housing, the outer contour of which essentially corresponds to the outer contour of the support device 2, in other words, approximating a piston shape. The wall sections or the rod-like molded body have predetermined breaking points, so that housing sections 33 formed by them can be easily broken off or otherwise separated from housing sections 33 or sections of the molded body still arranged within the build chamber walls after these housing sections 33 have been extended.The support device 2 is provided with side wall guide sections that interact with guide elements in the lower region 14 of the build chamber 10. The guide elements comprise at least one motor-driven element, e.g., in the form of a friction wheel, with which the support device 2 and / or the section additively built upon it can be moved vertically within the build chamber walls. The motor-driven element acts on the outer contour of the support device 2 or on the housing-forming wall sections of the housing, which are essentially aligned with the outer contour of the support device. The exemplary embodiment does not show that additional powder-tight elements may be arranged to prevent powder residues from falling out of the build chamber area through the dispensing opening 13 in the lower region 14 of the build chamber 10.
[0016] Additionally, it may be provided that a clamping device for the outer housing-forming wall sections is provided in the lower area 14 of the construction chamber 10 in order to facilitate the breaking off of already completed housing sections 33 that have been pulled downwards out of the construction chamber 10.
[0017] Out of Fig. Figure 3 clearly shows that the support device 2 forms a starting section of an overall rod- and / or tube-like component, in which cooling lines 21 can be arranged in addition to a clear interior space. It is significant that the entire construction process can be carried out as a continuous process, meaning that the progress of the construction process is essentially only limited by the fact that elements protruding downwards from the construction chamber are occasionally removed, i.e., broken off or otherwise separated. Of course, a cutting device can also be provided to prevent the uncontrolled breaking off of the completed sections.
[0018] In Fig. Figure 2 shows that the housing-forming walls 32 support intermediate shelves 34, which in turn can support the objects 7a, 7b, 7c and further objects built on top of them, so that the housing-forming walls and the intermediate shelves 34 or fewer form enclosed cells which, after the construction process, contain the objects 7a, 7b, and 7c as well as unsolidified powder. It may be provided that a removal chamber is arranged below the removal opening 13, which is combined with a glovebox-like device to allow the objects to be removed, for example, in a protective gas atmosphere or to prevent powdery building material from contaminating the area around the device. Such a removal chamber is shown in Fig.The section 1 below the extraction opening 13 is only briefly indicated. It is within the scope of the invention to design this extraction chamber on the underside of the construction chamber 10 to be removable, so that after a certain construction progress, the objects arranged therein, together with their building cells consisting of the wall sections 32 and intermediate floors 34, can be freed from the powdery building material and removed at another location. An empty extraction chamber can then be attached to the underside of the device 1 to receive further objects growing downwards from the device 1 more or less continuously. The extraction chamber is thus designed as an exchangeable extraction chamber. REFERENCE MARK LIST 1 Device 2 Carrying device 3 Coating device 5 scanners 6 Output radiation 7 objects 8 calculators 9 Focus 10 Construction Chamber 11 Construction chamber wall 12 surface area of 2 13. Sampling opening 14 bottom of 10 15 Irradiation facility 20 molded bodies 21 cooling lines 30 cases 32 wall sections 33 housing sections 34 intermediate floors 40 side wall guide sections 41 guide elements 60 cell bodies
Claims
A method for producing three-dimensional objects (7a, 7b, 7c) by successively solidifying layers of a powdered build-up material that can be solidified by means of electromagnetic radiation at the locations corresponding to the respective cross-section of the objects (7a, 7b, 7c), comprising the following features: - providing a support device (2) for carrying the objects (7a, 7b, 7c) within a build-up chamber (10); - providing a coating device (3) for applying layers of the build-up material to the support device (2) or a previously formed layer; - providing an irradiation device (15) for irradiating layers of the build-up material at the locations corresponding to the respective cross-section of the object (7a, 7b, 7c), wherein several separate objects (7a, 7b, 7c) are additively built up one above the other on the support device (2) in a continuous process, and are separated from one another by lid-like intermediate floors (34) of a housing (30).and- providing the build chamber (10) in a design open at the bottom such that the support device (2) is guided within the build chamber (10) in such a way that it can be extended downwards out of the build chamber (10) synchronously with the build progress and is guided by the wall sections built on it when extended, wherein the wall sections are the outer walls (32) of cells (60) formed by housing sections (33), which are built up additively together with the objects (7a, 7b, 7c) and enclose the objects (7a, 7b, 7c), and wherein the removal of the objects (7a, 7b, 7c) takes place via a removal opening (13) arranged below the build level or coating level.