Conveyor device for powder construction materials

Abstract

The invention relates to a conveyor device (40) for an apparatus (1) for the additive manufacture of at least one component (2) from a powder construction material (13, 13', 15) by means of selective at least partial solidification of the construction material (13). For conveying construction material (13') in the apparatus (1), the conveyor device (40) has a chain-driven conveyor (50), preferably a chain conveyor (50), with at least one toothed wheel (51). At least one inter-tooth region (52) between two adjacent teeth (57, 57') of the toothed wheel (51) comprises an escape space (54, 54') for the powder construction material (13'). The invention also relates to an apparatus (1) for the additive manufacture of at least one component (2), and to a method for the additive manufacture of at least one component (2).

Description

[0001] Conveying device for powdered building material

[0002] The invention relates to a conveying device for a device for the additive manufacturing of at least one component from a powdered building material by selectively at least partially solidifying the building material, a device for additive manufacturing with a conveying device and a method for the additive manufacturing of at least one component.

[0003] Additive manufacturing processes are becoming increasingly relevant in the production of prototypes and, more recently, in series production. In general, “additive manufacturing processes” refers to manufacturing processes in which a finished product is built up by depositing material, also known as build material, based on digital 3D design data. These finished products are typically referred to as components. The build-up is usually, but not necessarily, layered. The term “3D printing” is often used as a synonym for additive manufacturing. The production of models, samples, and prototypes using additive manufacturing processes is often referred to as “rapid prototyping,” the production of tools as “rapid tooling,” and the flexible production of series components as “rapid manufacturing.”

[0004] A key aspect of additive manufacturing processes based on a powdered material ("powder-based") is the selective solidification of the powdered build-up material. This solidification can often be achieved by irradiation with radiant energy, e.g., electromagnetic radiation, especially light and / or thermal radiation, but possibly also with particle radiation such as electron beams. Examples of additive manufacturing processes that use irradiation include "selective laser sintering" and "selective laser melting."This involves repeatedly applying thin layers of a build-up material, usually in powder form, on top of one another. In each layer, the build-up material is selectively solidified in a "welding process" by spatially limited irradiation of the areas that are to become part of the component after production. This process involves partially or completely melting the powder grains of the build-up material using the energy locally introduced by the radiation at that point. During cooling, these powder grains then solidify together to form a solid. In most cases, the energy beam is guided across the build area along solidification paths, and the remelting or solidification of the material in the respective layer takes place in the form of "weld paths" or "weld beads," so that ultimately the component contains a multitude of such (component) layers formed from weld paths.

[0005] To produce a component, a larger volume of powdered build material is often initially made available in a process chamber than is actually processed to manufacture the component. Particularly when build material is applied layer by layer, but not only there, a reserve can be provided in each material layer to avoid a deficit of build material in the component layer. In order to be able to reuse excess, i.e. unused, build material, additive manufacturing machines are known in which excess build material is collected in a first container located close to a build field and then transferred by means of a transport device to a second, larger collection container, which is typically located further away from the build field.

[0006] Known transport systems, for example, are implemented as screw conveyors and can have the disadvantage that the removal of excess build material from the heat-affected zone of the additive manufacturing machine occurs relatively slowly. This can lead to heat-related damage and significant powder aging, particularly with plastic-based build materials, which negatively impacts the recycling rate. The frictional heat generated during operation of the screw conveyor can also reduce the quality of the powder. Build material can become caked on the screws during operation, reducing the conveying capacity of the screw conveyor.

[0007] A common problem with transport systems using chain conveyors is that the powdered build-up material adheres to sprockets or chains and is compacted, at least in places where the chain engages with a sprocket. As a result, adhesions that are difficult to remove can form, e.g. particles of the build-up material that are at least partially solidified by pressure and / or heat and, for example, form agglomerates. This can lead to the chain skipping during operation, which can result in a standstill or defect in the transport system. This problem can generally occur with a chain conveyor that transports powdered build-up material in an additive manufacturing machine, i.e. regardless of the transport direction of the build-up material in the manufacturing machine and the position of the chain conveyor within the manufacturing machine.It is an object of the present invention to provide a conveying device for a device for the additive manufacturing of a component from a powdered building material as well as such a device with a conveying device and a method for the additive manufacturing of a component, with which at least some of the disadvantages mentioned can be reduced or avoided.

[0008] This object is achieved by a conveying device according to patent claim 1 and a device according to patent claim 13, as well as by a method according to patent claim 15.

[0009] A conveying device according to the invention is designed to be operated in a device for the additive manufacturing of three-dimensional components from a powdered building material by selectively at least partially solidifying the building material. The conveying device is designed to interact with other components of the device, hereinafter referred to as additive manufacturing device or AM machine for short, during the additive manufacture of a respective component. The conveying device is structurally adapted to the conditions in a process chamber of the AM machine during an additive manufacturing process. The conveying device can preferably be reversibly integrated into an AM machine. The conveying device can preferably be designed as a removable machine component for equipping an AM machine.

[0010] The conveying device is designed, particularly when mounted in an AM machine, to convey powdered build material within the AM machine. Conveying powdered build material means that the build material is transported within the AM machine, particularly between two or more different locations. In the description of the invention, the powdered build material is referred to synonymously as powder.

[0011] According to one embodiment of the invention, the conveying device can be designed, in particular mountable in an AM machine, such that powder is transported in the direction of a build field of the AM machine. In particular, the conveying device can be designed and / or mountable such that (fresh) powder is supplied by means of the conveying device to an application device of the AM machine, which applies the powder to a build field in the process space of the AM machine during additive manufacturing. Consequently, the conveying device can be designed and / or mountable such that the powdered build material is transported to a processing location in the AM machine by means of the conveying device. Accordingly, the conveying device can be integrated into the application of build material to the build field of the AM machine.

[0012] According to one embodiment, the conveying device is alternatively or additionally designed, in particular mountable in the AM machine, such that build material can be transported away from a build area of ​​the AM machine. In particular, the conveying device can be designed and / or mountable such that unused or excess powder is removed from the immediate vicinity of the build area. Unused or excess build material is understood to mean, in particular, the portion of the powder on the build area that is not used to form the component. When powder is applied layer by layer to the build area, the unused or excess build material corresponds, in particular, to that portion of the powder from a respective application process that is not used to build up a powder layer.In this case, the unused build material, also referred to as material residue, can be brought upstream of a coater of the AM machine as a reserve or surplus and removed from the build field at the end of the application process. Alternatively or, preferably, additionally, unused build material that was applied to the build field during a (first) powder application and was not solidified during a subsequent irradiation process can be removed from the build field (as unused build material) during a subsequent (second) powder application and / or by a movement of a coater of the AM machine, in particular by the coater. Furthermore, it is possible, for example, that part of the build material is not applied to the build field during an application process (e.g., due to an error), but rather to an area immediately surrounding the build field; this build material is also referred to as unused build material.Accordingly, the conveying device can be designed and / or mounted in such a way that unused powder, in particular unsolidified powder, is conveyed away from the build area of ​​the AM machine by means of the conveying device. Preferably, the conveying device can be designed and / or mounted in the (immediate) vicinity of the build area, so that powder that is discharged from the build area, for example, after completion of an application process and / or is discharged from the build area by a coater when it moves on the build area, can be conveyed away from the build area by the conveying device. For transporting powder in the AM machine, the conveying device has at least one chain-driven conveyor. The chain-driven conveyor comprises at least one, preferably several, chains, in particular roller chains. Furthermore, the chain-driven conveyor comprises at least one single, preferably several, gear wheels.The respective gears are preferably implemented as sprockets. The gears, in particular the sprockets, engage with an associated chain during operation of the conveyor device. The chain-driven conveyor preferably has at least one conveying element that interacts with the chain and serves to move the building material. Furthermore, the chain-driven conveyor preferably comprises a controllable drive means, e.g., an electric motor, to move the at least one chain to transport the building material. The chain-driven conveyor can preferably be implemented as a chain conveyor.

[0013] According to the invention, at least one intermediate tooth region of the gearwheel comprises an escape space for the powdered building material between two adjacent teeth of the gearwheel, preferably of the sprocket, or between two teeth of the gearwheel that are adjacent to one another in the circumferential direction and spaced apart. Preferably, the escape space can be formed by at least a portion of the intermediate tooth region of the gearwheel itself. The intermediate tooth region is a region of the gearwheel that lies between two adjacent or consecutive teeth. The intermediate tooth region can, in particular, be a (material) region of the gearwheel that lies between two mutually facing tooth flanks of two adjacent teeth and / or between two tooth roots of two adjacent teeth.

[0014] The escape space is particularly designed such that a chain meshing with the gearwheel is spaced apart from a material body of the inter-tooth region in the escape space. This means that the meshing chain preferably does not directly contact the inter-tooth region in the escape space.

[0015] The escape space is particularly designed such that a chain engaging with the gearwheel is spaced apart from the powdered build-up material present in the escape space. This means that the engaged chain preferably does not directly contact the powdered build-up material present in the escape space.

[0016] The deflection space is preferably designed to guide powdered build-up material that impacts the deflection space during operation away from the interdental area and / or to temporarily accommodate the build-up material. Contact between powder and the deflection space can occur during operation of the conveying device and / or during operation of an AM machine with the conveying device by powder being thrown against the deflection space or trickling down onto it. Accordingly, the deflection space can preferably be designed such that powder that impacts the deflection space is guided away from it by gravity, in particular by sliding off.

[0017] Advantageously, the conveying device according to the invention can achieve the fastest possible transport of build material in an AM machine, e.g., compared to known screw conveyors. This has the advantage that powder aging can be reduced, particularly during feeding into a heat-affected zone and / or during removal therefrom. This can have a beneficial effect on the material properties of the fresh build material, i.e., the material still to be processed. Furthermore, the degree of powder recycling can be improved by quickly transporting excess build material away from the heat-affected zone.

[0018] Another advantage of the escape space is that it allows critical areas of the gear that are prone to powder adhesion to be reduced compared to conventional gears. Critical areas are particularly the surface areas of the gear that are subjected to tensile and / or compressive forces by a chain during operation of the conveyor device. With known devices, an accumulation of powder and subsequent compaction by the chain can lead to flat, difficult-to-remove adhesions on the gear during operation, particularly in a chain contact area of ​​the gear, which can be arranged in the area between the teeth. The chain contact area corresponds to a contact zone between the gear and a chain that is in engagement with it. The chain contact area is the part of a surface of the gear that is directly contacted by the chain during operation of the conveyor device.Advantageously, the space between the teeth (a critical area) allows the surface areas of the gear where buildup can potentially occur to be kept as small as possible. This can at least reduce unwanted buildup on the gear compared to conventional gears, which can have a positive effect on the proper running of the chain and trouble-free operation of the conveyor system. Reducing powder accumulation and buildup on the gear also helps to reduce buildup on the chain.

[0019] A device according to the invention for the additive manufacturing of at least one component comprises a feed device for feeding a powdered build material into a process chamber, an irradiation device for selectively at least partially solidifying the powdered build material by irradiation with at least one energy beam, and at least one conveying device according to the invention. Preferably, the AM machine can have two or more separately controllable conveying devices. Preferably, two conveying devices can be arranged on opposite sides of a build container of the AM machine.

[0020] The respective conveyors can have different functions in the AM machine. For example, a first conveyor can be designed to transport (fresh) powder to a processing location in the AM machine, while a second conveyor can be designed to remove excess powder from the build area of ​​the AM machine.

[0021] A method according to the invention for the additive manufacturing of at least one component, preferably a plurality of components, comprises at least the following recurring steps:

[0022] In one step, a powdered build material is fed into the process chamber of an AM machine, in particular by applying the build material layer by layer onto a build area. In a further step, the build material is selectively irradiated with at least one energy beam in order to selectively at least partially solidify the build material to form a component layer. Partial solidification of the build material of a previously applied powder layer is preferably achieved by selectively irradiating points of the powder layer corresponding to a cross-section of the component to be produced with the energy beam.

[0023] In a further step, build-up material is conveyed in the AM machine by means of a conveying device, in particular a conveying device according to the invention. The conveying device has at least one chain-driven conveyor, preferably a chain conveyor, with at least one gear, preferably a sprocket, wherein at least one intermediate tooth region of the gear, between two adjacent teeth of the gear, comprises an escape space for the powdered build-up material. The method is preferably carried out such that powder which comes into contact with the escape space is guided away from the intermediate tooth region through the escape space and / or is temporarily absorbed by the escape space. The method is preferably carried out in an apparatus for additive manufacturing according to the invention.Furthermore, the method can provide for excess build-up material, in particular from a respective powder layer, to be transferred into an intermediate container of the conveyor. The excess build-up material can be transported by the conveyor from the intermediate container to an overflow container associated with the conveyor.

[0024] Advantageously, the AM machine, the manufacturing method, and the conveyor device according to the invention are based on the same inventive concept. This consists of a conveyor device for an AM machine with a chain-driven conveyor with at least one gear, wherein at least one intermediate tooth region of the gear includes an escape space for the powdered build-up material. Thus, the AM machine and the manufacturing method also benefit from the same advantages as described with reference to the conveyor device.

[0025] Further, particularly advantageous embodiments and developments of the invention emerge from the dependent claims and the following description, wherein the independent claims of one claim category can also be developed analogously to the dependent claims and embodiments of another claim category and, in particular, individual features of different embodiments or variants can be combined to form new embodiments or variants.

[0026] The conveyor system can be used in various AM machines, regardless of their operating principle. For better understanding, the invention is described below, without limitation, using an AM machine and a manufacturing method in which powdered build material is applied layer by layer to a build field and then selectively solidified. Accordingly, several material application levels or material layers can be built up one after the other in a build field in the AM machine or in the manufacturing method. The build material can be a polymer-based powder. However, the invention is not limited to this, but also encompasses other powdered build materials. For example, metal powder, ceramic powder, filled or mixed powders, sand, and mixtures of different materials can be used.To produce a component, the build material of a previously applied material layer is solidified by irradiating the build material with at least one energy beam generated by the irradiation unit. This refers to an energetic beam of photons or particles, e.g., a light beam or an electron beam. In principle, the AM machine can also have multiple irradiation devices, which can then be controlled in a coordinated manner using control data. Furthermore, the energy beam can also consist of several superimposed energy beams. Preferably, the build material is selectively solidified in each of its layers by selective irradiation of locations corresponding to a cross-section of the component to be produced.

[0027] The AM machine preferably comprises a removable build container or interchangeable frame for holding the build material. The build container can preferably form the build field, in particular a region of the build container located within an opening. The AM machine preferably has a coater for applying the build material layer by layer to the build field. The coater is preferably part of the feed device. The AM machine preferably has further components that are generally known from additive manufacturing devices and are therefore not described further. This particularly relates to a control device that controls all components of the AM machine for producing a component, in particular according to the described manufacturing method. The control device of the AM machine can preferably be designed to also control the operation of the conveyor device.

[0028] The additive manufacturing device, as described, comprises at least one conveying device. The conveying device is preferably designed in such a way, in particular arranged in the process space of the AM machine, that unused or excess build material is removed from the build area in the process space of the AM machine. The unused or excess build material can comprise at least build material from a (respective) application process that is not used to build a powder layer and / or can comprise at least build material that was applied to the build area during a (first) powder application and was not solidified during a subsequent irradiation process and that is discharged from the build area by the coater of the AM machine during a subsequent (second) powder application and / or by a movement of the coater.Preferably, by means of the conveyor device, excess build material can be transported from an intermediate container of the conveyor device into an overflow container which is assigned to the conveyor device. The intermediate container is at least designed to receive the remaining material from a single coating process. The intermediate container is preferably arranged in the immediate vicinity of the build area. Preferably, the intermediate container can directly border or connect to the build container. The intermediate container can extend along an entire side of the build area, e.g., along an entire longitudinal or transverse extent of the build area. In particular, the intermediate container can be arranged such that an upper side or upper edge of the intermediate container is flush with a current working plane of the AM machine or slightly below it (in the vertical direction).

[0029] In a corresponding manner, a preferred manufacturing method can provide for (fresh) powder to be applied layer by layer on the build area, with excess build material, in particular of a respective powder layer, being transferred into the intermediate container of the conveyor device, and with the excess build material being introduced from the intermediate container by means of the conveyor device into the overflow container, also referred to as a collecting container. To apply a powder layer to the build area, a coater can be guided over the build area as a movable beam at a distance from the build area corresponding to a planned layer thickness, pushing a portion of the powder in front of it and largely consuming it in the process. The excess build material that is fed in front of the coater can be discharged from the build container at the end of each application process and introduced into the intermediate container close to the build area.

[0030] Although the conveyor system is generally designed for transporting powdered build material in an AM machine, advantageous developments of the conveyor system are described, without limitation, with reference to a conveyor system used to remove excess powder. DE 10 2017 126 665 A1 discloses a conveyor system that serves a similar purpose, albeit without the special chain-driven conveyor. Reference is made to the aforementioned application, the content of which is hereby incorporated into this application.

[0031] The AM machine can generally have two or more conveyors. The respective conveyors can preferably be arranged in the immediate vicinity of the construction area, e.g., directly adjacent to it. Depending on the working method of the coater, namely a layer build-up in only one working direction or in two opposite directions, the AM machine can comprise one or two conveyors. If two conveyors are provided, they are preferably each located behind the build container in the working direction of the coater. The invention is described below with reference to an AM machine with only one conveyor, which is also intended to encompass the arrangement of multiple conveyors.

[0032] The chain-driven conveyor of the conveyor device can preferably have two, in particular four sprockets. During operation, two sprockets are preferably in engagement with an endless chain. The invention is described below, without limitation, with reference to a roller chain (as a chain) and a sprocket (as a gear). In principle, other types of chains can also be used, such as chains in which sleeves engage with the teeth of the sprocket, chains with an offset, sealed chains or the like. The advantageous developments described with reference to a single sprocket can equally apply to a plurality of sprockets. It is pointed out that the conveyor device can in principle also have different sprockets, in particular with regard to the design of the escape space.For example, in addition to a chain wheel according to the invention, the conveyor device can also have at least one conventional gear wheel, ie without the special intermediate tooth area, e.g. if this gear wheel is subjected to less or no powder during operation due to its position.

[0033] The respective sprocket (as a gear) can preferably have two or more spaced-apart, preferably different, escape spaces for the impinging powdered building material. Preferably, an escape space can be formed between each two adjacent teeth of the sprocket. Preferably, a separate escape space can be arranged in each inter-tooth region of the sprocket. The invention is described below, without limitation, with reference to such a sprocket mentioned above. Different escape spaces of the same sprocket can be designed differently.

[0034] The escape space for the impinging powdered build-up material can comprise a clearance in the interdental area. It is possible for the escape space to be implemented in the form of a clearance. A clearance can preferably be formed by a specific material recess in the material body of the interdental area. Different clearances can be formed in the respective interdental areas.

[0035] According to one embodiment of the invention, the respective escape space can have a slip surface designed to guide build-up material away from or divert it from the inter-tooth region of the sprocket. In particular, the slip surface can guide powder away from at least some areas of the inter-tooth region. The slip surface can preferably be formed by a clearance in the inter-tooth region. The slip surface can preferably be formed by the material of the inter-tooth region itself. Accordingly, the slip surface can be part of the inter-tooth region.

[0036] The respective sliding surfaces are preferably designed such that powder that strikes the sliding surface slides along the sliding surface by gravity to be guided away from the inter-tooth region. In this embodiment, the respective sliding surface can therefore form a kind of "sloping floor" of the escape space for the powder. The individual sliding surfaces can preferably be spaced from one another by a tooth of the sprocket. Preferably, a sliding surface can be formed between each adjacent tooth. The sliding surfaces of the same sprocket can fundamentally be designed differently.

[0037] Preferably, the respective slip-off surface can be formed by a tooth base between two adjacent teeth of the sprocket (as a gear). Depending on the design, the respective slip-off surface can completely connect two adjacent teeth. This means that the slip-off surface can then extend along a longitudinal extent of the tooth base from one tooth to the adjacent tooth (the longitudinal extent of the tooth base runs along a circumference, i.e., orthogonal to the radius of the sprocket).

[0038] As is generally understood, the tooth root is the (material) area of ​​the sprocket that connects two adjacent teeth. The tooth root is the material area of ​​the sprocket that connects two opposing tooth flanks of two adjacent teeth, particularly seamlessly.

[0039] The respective tooth base of the sprocket preferably comprises an upper surface that points away from a center point of the sprocket. This tooth base upper surface can preferably be aligned approximately parallel to a rotational axis of the sprocket. Preferably, a (same) tooth base can have a tooth base upper surface that is approximately parallel to a rotational axis of the sprocket and at least one slip-off surface.

[0040] To form the slip-off surface between two adjacent teeth, the respective sprocket (as a gear) can preferably have a material cross-section that tapers toward a respective tooth base. In particular, the material cross-section of the sprocket can reduce radially outward toward a respective tooth base top surface. For example, the material cross-section can taper radially outward, preferably toward the tooth base top surface, from a center point of the sprocket or from another point radially spaced from a center point of the sprocket.

[0041] The intertooth region can have a relief, particularly in the tooth base, in order to form the anti-slip surface by means of the relief. Particularly preferably, the intertooth region can comprise a tooth base with a tooth base upper surface and an adjacent anti-slip surface. This means that a width and / or an area of ​​the tooth base, particularly the tooth base upper surface, can be reduced by a certain amount (compared to an original tooth base) by forming the relief. In principle, at least part of the tooth base can also be formed by an anti-slip surface.

[0042] Advantageously, a sprocket with slip-off surfaces can be used to achieve the most trouble-free and reliable operation of the conveyor system in a simple yet effective manner. The tooth base is usually a critical area of ​​the sprocket, which is prone to powder accumulation and adhesion. Advantageously, the tapered material area or material cross-section allows an area of ​​the respective tooth base, in particular an area of ​​the upper side of the tooth base, to be designed to be relatively small compared to conventional sprockets. This allows the area of ​​the tooth base to be as small as possible for potential adhesions or deposits. Preferably, the powder that strikes the slip-off surface can be carried away from the slip-off surface as completely as possible by gravity and / or due to a rotational movement of the sprocket, whereby larger accumulations of powder are avoided.A further advantage may be that the sliding surface adjacent to the (reduced) top surface of the tooth base can also assist in removing powder from the top surface of the tooth base. The chain wheel (as a gear) of the conveyor device can comprise one or more of the elements described below to form the respective sliding surface; a combination of these elements is also possible on the same gear.

[0043] The sprocket can have at least one slip-off plane as a slip-off surface, wherein the slip-off plane originates from the tooth base. The slip-off plane can preferably originate in the tooth base and / or can contact the tooth base. In particular, the slip-off plane can (directly) adjoin the top surface of the tooth base. The slip-off plane is preferably formed by a (material) region of the sprocket that extends from the tooth base, in particular from the top surface of the tooth base, radially or obliquely radially inward, i.e., in the direction of the rotational axis of the sprocket.

[0044] Preferably, a (respective) slip-off plane can comprise two or more (sub)regions as a slip-off surface, wherein the individual (sub)regions are designed differently, in particular geometrically. These (sub)regions can, for example, be adjacent to one another in the radial direction, thus forming different "radial sections" of the slip-off surface.

[0045] Preferably, the slip plane can be arranged obliquely to the longitudinal extension of an adjacent tooth. For example, the slip plane can form an inclined surface with respect to the longitudinal extension of the tooth. The longitudinal extension of the tooth is understood to be the longest extension of a tooth in the radial direction.

[0046] Preferably, the slip plane is arranged tilted relative to a tooth's longitudinal extent, particularly with respect to its longitudinal extent. The angle of inclination can be, for example, at least 30°, preferably at least 40°, preferably at least 45°, particularly preferably at least 50°, in particular 60° or more, relative to the tooth's longitudinal extent of an associated tooth. The slip plane can have a constant angle of inclination relative to its longitudinal extent. It would also be possible for the slip plane to have different angles of inclination relative to its longitudinal extent.

[0047] The longitudinal extension of the slip plane or slip surface is understood to be the longest extension of the slip plane, starting from the tooth base, preferably the top surface of the tooth base, in the direction of the sprocket's rotational axis, i.e., in a radial or oblique radial direction. For example, the sprocket can have a material cross-section in the shape of a rectangular trapezoid in the area of ​​the slip plane. In this case, a short base side of the trapezoid can form the top surface of the tooth base, with one leg (not orthogonal to the base side) forming the slip plane.

[0048] Alternatively or additionally, the sprocket (as a gear) can have at least two slipping surfaces extending from the same tooth base, which are arranged on opposite sides of the sprocket, each forming a specific angle to each other and oblique to the longitudinal extension of the tooth. Accordingly, the two slipping planes each form a specific, even different, angle to the longitudinal extension of the tooth.

[0049] In this embodiment, the intertooth area then comprises two separate slip planes or slip surfaces, which together form the escape space. The two slip planes can directly contact each other, forming the top surface of the tooth base. The material thickness of the tooth base (at least in some areas) can then be several times thinner than the material thickness of the teeth, particularly in the area of ​​a tooth root.

[0050] In principle, however, it is also possible for the two slip planes to extend on either side of a tooth base (without forming the top surface of the tooth base itself). For example, the sprocket can have a material cross-section in the shape of an isosceles trapezoid in the intertooth area. In this case, a short base side of the trapezoid can form the tooth base, particularly the top surface of the tooth base, with each side forming a slip plane.

[0051] Preferably, an (internal) angle between a respective slip-off plane and a tooth longitudinal extension (i.e. in the radial direction of the gear or in a direction perpendicular to the axis of rotation of the sprocket) can be at least 15°, preferably at least 30°, more preferably at least 45° and / or at most 75°, preferably at most 65°, particularly preferably at most 60°. In principle - as will be explained later - the angle of inclination of the slip-off plane in an intermediate tooth region can also change in the radial direction (in relation to a direction perpendicular to the axis of rotation of the sprocket), e.g. in sections or continuously (in the form of an arc). Thus, the gear can have at least one curved, preferably concave, slip-off plane emanating from the tooth base, in particular from the top side of the tooth base, as a slip-off surface. The slip-off plane can preferably be concave at least in sections along its longitudinal extension.Alternatively or additionally, the slip-off plane can have a curved, in particular concave, surface in a transverse extension that runs orthogonally to the longitudinal extension of the slip-off plane. A radius of curvature of a (concave) slip-off surface in the direction of the (radially extending) longitudinal extension and / or the transverse extension can, for example, be in a ratio to the gear wheel radius of at least 1:8, preferably at least 1:4, particularly preferably 1:2, and / or at most 8:1, preferably at most 4:1, particularly preferably 2:1.

[0052] Preferably, a curvature and / or an inclination of a slipping plane can be compatible with other design parameters of the gear or can be adapted to it. For example, a height of the slipping plane in the radial direction, i.e. in a direction perpendicular to the axis of rotation, can be influenced by a certain curvature or by a certain inclination of the slipping plane and a thickness of the gear. Given defined geometric conditions, e.g. that the inclination should occur over a certain radial section according to a radius of curvature, a parameter can even be defined indirectly by the other parameters. For example, if two parameters (thickness and curvature or inclination) are defined, a third (height) can be given automatically. In other words, a curvature oran inclination of the slipping plane at a certain height of the slipping plane in the direction of extension of the gear, and at a certain thickness of the gear only adjustable within certain limits.

[0053] Preferably, the slip surface or slip plane is as steep as possible at its free end (facing the outer edge of the sprocket). The height of the slip plane and / or the curvature and / or the inclination of the slip plane and / or the thickness of the gear can be selected to achieve the steepest possible free end of the slip surface.

[0054] As mentioned, a slip plane can have at least two different angles of inclination relative to its longitudinal extent, i.e. the slip plane has at least two "radial sections" in the radial direction which are inclined differently relative to the radial direction of the gear. Preferably, a certain section of the slip plane, which comprises the free end of the slip plane, is steeper along the longitudinal extent of the slip plane than another section along the longitudinal extent of the slip plane. This is achieved, for example, in that an angle of inclination to the axis of rotation of the gear of a section which comprises the free end of the slip plane along the longitudinal extent of the slip plane is greater than the angle of inclination to the axis of rotation of the gear of another section of the slip plane.

[0055] A steep slipping surface end is achieved with a concave curvature with a relatively large radius of curvature and a relatively small thickness of the gear.

[0056] In addition, other non-straight and / or non-circular (circular-arc-shaped) slip planes (both in the longitudinal and transverse extension, i.e., in the circumferential direction) are possible. For example, parabolic, elliptical, hyperbolic, and / or exponential slip planes can be realized. A curved, non-circular slip plane can be compatible with or adapted to other design parameters of the sprocket, analogous to the slip planes already disclosed herein.

[0057] Particularly in the case of non-circular, curved slip planes, a further design parameter can be a distance between a position on the gear (e.g. from the tooth end and / or from the center of the gear) and the (virtual) origin of a curved slip plane. The origin of a (virtual) curved surface in three-dimensional space is generally understood to be a point that lies at the minimum of the surface in three-dimensional space. A curved slip plane can, in turn, be defined or described by a partial area of ​​such a curved surface in three-dimensional space. The position of the origin relative to the gear can also (co-)determine which part of the (virtual) curved surface defines the actual slip plane.In particular, the position of an origin of the curved surface in the radial and axial (along the rotation axis) direction of the gear can also define the course of the surface of the slipping plane along a radial direction of the gear.

[0058] The origin of a slip plane can, in a (fictitious) three-dimensional representation, in particular also lie outside the volume of the gear. Preferably, in the case of a concavely curved slip plane, the origin is arranged such that a radially inner slip plane end is as steep as possible (i.e., the slope is as steep as possible in a region located radially inward with respect to the radius of the gear). A steep slip plane end can be achieved with a small distance between a position on the gear (e.g., from the tooth end and / or from the center of the gear) and the origin of the slip plane. In particular, it is advantageous - as will be shown later using an exemplary embodiment in the figures - that the origin of a parabola and / or an ellipse and / or a hyperbolic and / or exponential function (serving to define the slip surface) is lower in comparison to the height of the slip plane (i.e.the origin is located lower in the radial direction than the end of the slide plane) so that the slide plane is as steep as possible at the end of the slide plane.

[0059] For the sake of completeness, it should be noted that even in an inter-tooth region with two slip-off planes (facing two opposite sides of the gear), it is possible for at least one slip-off plane (or both) to have a curvature. For example, the material cross-section of the gear in the inter-tooth region can be doubly concave and / or convex to form the slip-off planes. The curvature of the two slip-off planes can be different, for example, according to the embodiments explained above and combinations thereof.

[0060] In principle, the respective slip plane can also be only partially curved and / or partially inclined, regardless of the further design of the interdental area. This means that the slip plane can, for example, have various radial sections that are differently inclined or curved in the radial direction.

[0061] Furthermore, the respective tooth base upper surface, which points away from a gear center, can be concave at least in sections, regardless of the further design of the inter-tooth area.

[0062] The slip-off surface or the slip-off plane can be implemented, for example, in the form of a curved recess in the material body of the sprocket. Preferably, the slip-off surfaces or the slip-off planes can each be pocket-like. Preferably, at least one pocket can extend in a tongue-like manner, starting from the tooth base, in particular starting from the top side of the tooth base, in the direction of a sprocket center. Preferably, the pocket can be arc-shaped or form a semicircle at its end, i.e. pointing in the direction of the sprocket center. An arc-shaped pocket or a semicircular pocket can be implemented in accordance with the embodiments explained above or combinations thereof. As mentioned, not only a straight but also an arc-shaped design of the slip-off planes in the transverse extent, i.e. in the circumferential direction of the gear, is possible, wherein here too sections in the circumferential direction orDifferent shapes can be selected for each sector of the circle. In other words, the entire three-dimensional surface of the slip plane can be optimized for the respective application.

[0063] The sprocket of the conveyor device is preferably designed such that a ratio between the radial longitudinal extent of the slip surface (calculated from the radially inner slip surface end to the tooth base surface), in particular the slip plane, and a radial longitudinal extent (tooth longitudinal extent) of an associated tooth (calculated from the tooth base surface to the radially outer end of the tooth) is at least approximately 1:2, preferably at least approximately 1:1.5 and / or at most approximately 1:0.25, preferably at most approximately 1:0.5. An associated tooth is preferably a tooth that borders the slip surface.

[0064] The sprocket of the conveyor device can be designed such that a ratio between the longitudinal extent of the slipping surface (calculated from the radially inner slipping surface end to the tooth base surface), preferably the slipping plane, and a radius of a wheel body of the gear or sprocket (ie the radial distance between the axis of rotation of the gear and the tooth base surface) is at least 1:10, preferably at least 1:5 and / or at most 1:1.5, preferably at most 1:2. Preferably, a ratio between the longitudinal extent of the slipping surface or slipping plane and the radius of the wheel body of the gear can be approximately 1:3.

[0065] The wheel body is understood to be the base body of the sprocket without the outer teeth arranged on it. The wheel body can preferably have a circular outer circumference. The wheel body is preferably defined by the root circle of the sprocket.

[0066] Advantageously, in a conveyor system with the previously described deflection planes, the impacting powder can be guided away from the inter-tooth area particularly reliably. Furthermore, deflection planes with a large longitudinal extension have the advantage that they can be formed comparatively easily in the sprocket, making the sprocket more cost-effective to manufacture.

[0067] According to one embodiment of the invention, the respective escape space for the construction material can comprise a clearance in the inter-tooth region, which is designed such that the clearance creates a specific distance between a chain roller of a chain that is in engagement with the sprocket and the tooth base of the inter-tooth region. In other words, the clearance can be designed such that there is no (direct) contact between the engaged chain and the tooth base in the inter-tooth region (in the region of the clearance). As described, a clearance is understood to mean a specific material-free space in the material body of the sprocket or a specific material recess in the inter-tooth region of the sprocket.

[0068] The relief can preferably be formed in the tooth base itself. This means that the tooth base can be "deepered" at least in sections by the relief. Preferably, the upper surface of the tooth base can be shifted slightly toward the sprocket center by the relief (relative to an intertooth area without such a relief). Such a relief can preferably be formed in combination with a previously described anti-slip surface.

[0069] It is also possible for the escape space for the construction material to comprise a clearance configured such that a chain engaging with the sprocket, in particular a chain roller engaging with the sprocket, is supported (only) via two contact areas on two opposing teeth. The clearance, preferably the sprocket, can be configured such that a specific distance is formed between a chain roller of the chain engaging with the sprocket and the wheel body of the gear or the sprocket body.

[0070] The sprocket is preferably designed such that the chain then engages with the sprocket only via the teeth, wherein in the intermediate tooth region, in particular in the region between two adjacent tooth roots, there is no (direct) contact between the chain and the (remaining) sprocket. Accordingly, the respective chain roller then contacts the gearwheel only via two defined contact areas of the teeth. The clearance can extend along an entire longitudinal extent of the intermediate tooth region. The contact areas for supporting the chain roller can preferably be on the mutually facing tooth flanks of two consecutive teeth. Preferably, a distance between the two contact areas of the opposite teeth is less than a diameter of the chain roller of the chain. In particular, the sprocket is designed such that the clearance does not exceed the radius of the involute transition.Preferably, the grip conditions of the gearing are taken into account.

[0071] A sprocket with this type of clearance generally does not require a tooth base. This means that the individual teeth can be arranged on the sprocket's wheel body, with no direct connection between the tooth flanks of adjacent teeth. Instead, the tooth flanks can be adjacent to the wheel body or to a tooth root. The sprocket's teeth are arranged individually on the wheel body, with a material-free space (as a clearance) formed between two adjacent teeth that extends all the way to the wheel body.

[0072] Alternatively or additionally, the chain wheel, in particular the clearance, can be designed such that an engaged chain, in particular a chain roller, is supported (only) via two contact areas on two opposing teeth, wherein a certain distance is formed between a chain roller of the chain and a (lowered) tooth base.

[0073] Advantageously, a sprocket with such a clearance can effectively prevent unwanted buildup on the sprocket. Due to this clearance, the chain rests only on the teeth themselves, and during operation of the conveyor system, there is no direct contact between the chain and the rest of the sprocket in the area between the teeth. This prevents compression of any powder that may be present in the area between the teeth. Advantageously, the chain runs stably during operation despite such clearances in the sprocket.

[0074] It should be noted that a combination of different escape spaces for powder is possible with the same sprocket. In principle, it could also be provided that at least one intermediate tooth region has no escape space for powder. Furthermore, a conveying device according to the invention can have different sprockets, in particular sprockets with different escape spaces for powder. It is optionally possible to design the sprocket such that the sprocket as a whole is shaped such that its outer basic shape (regardless of escape spaces between the teeth) already has a radius of curvature and / or an inclination. For example, at least one side of the sprocket can have a radius of curvature and / or an inclination in the radial direction, starting from the teeth to the center. The entire curved and / or inclined (radial) surface of the sprocket can then form a slip-off surface for powder impinging on it.For example, at least one side of the gear can have a concave surface. It is also possible for only a specific part or section of the sprocket or sprocket surface to have a curvature and / or inclination. A curvature can be, for example, circular (arc of a circle), parabolic, hyperbolic, or exponential. Combinations of these curvatures are also possible. The teeth can have a different inclination or curvature than the rest of the sprocket.

[0075] Optionally, the conveyor device can have a scraper plate for powder, wherein the scraper plate is assigned to the sprocket. The scraper plate can be designed to scrape off build-up material adhering to the sides of the sprocket during operation. Accordingly, the scraper plate can be arranged transversely, essentially orthogonally, to a tooth longitudinal extension. Depending on the design of the sprocket, the scraper plate can optionally have a degree of bending that is adapted to a radius of curvature and / or to an angle of inclination of the sprocket. In principle, a separate scraper plate can be assigned to each gear of the conveyor device. The respective scraper plate can optionally have elastic scraper elements, e.g. bristles or the like. Advantageously, the lateral, in particular radial, areas of the sprocket can be kept as free of powder as possible during operation using a scraper plate.This can also improve the effectiveness of powder removal via the chute surfaces. For example, the scraper plate can mechanically assist the removal of powder from pocket-like chute surfaces.

[0076] Optionally, the sprocket can be designed such that a base area of ​​a respective tooth tip pointing away from the sprocket center corresponds to a maximum of 50%, preferably a maximum of 40%, more preferably a maximum of 30%, in particular a maximum of 20%, of a base area of ​​a tooth base. The tooth tip can preferably be flat and can be transverse, e.g. approximately orthogonal, to the longitudinal extent of the respective tooth. The tooth base of a tooth corresponds to the area resulting from a cross-section through the tooth root in the contact area with the wheel body. Advantageously, by reducing the size of the tooth tips, e.g. in two dimensions, the surface pressure between the sprocket and the chain can be increased during operation. This allows powder to be pressed out of the chain contact area. Alternatively or additionally, the width of the entire sprocket, and thus also of the teeth, could be reduced, e.g. in relation to the chain, in order to increase the surface pressure.

[0077] As described above, the conveying device can have at least one intermediate container for receiving build material. The intermediate container is preferably designed for temporarily receiving and / or transporting build material, in particular excess, in the AM machine.

[0078] Preferably, the conveying device can be designed such that the chain-driven conveyor, preferably the chain conveyor, operates as intended in the intermediate container. In particular, the chain conveyor can operate along a longitudinal extension of the intermediate container. The chain-driven conveyor can be arranged at least partially in the intermediate container. The intermediate container is preferably designed as a trough or tub.

[0079] An upper side of the intermediate container, which faces upwards (opposite the vertical direction) during intended use, can preferably be open. Preferably, the upper side can have an opening for receiving the powder along the entire longitudinal extent of the intermediate container. Preferably, the transport of powder (feed or removal) in the AM machine can involve moving the build material within the intermediate container by means of the chain-driven conveyor. The intermediate container can have an incline, in particular a gradient toward a destination for the powder.

[0080] The intermediate container can preferably be implemented as part of the conveyor system, with the other components of the conveyor system, in particular the chain-driven conveyor, being detachably coupled thereto. Preferably, the conveyor system and the intermediate container form a module that can be reversibly mounted in an AM machine.

[0081] The intermediate container is preferably designed to receive the unused material residue from at least one coating process, preferably a plurality of coating processes, i.e. a portion of the material residue that accrues during an entire manufacturing process of the component to be manufactured. The material residue can then be transferred from the intermediate container to the overflow container by means of the conveyor device, so that the intermediate container is at least partially emptied and available to receive a new material residue. The intermediate container can preferably be mounted in the AM machine in such a way that it can be coupled to the overflow container for transferring the powder. The overflow container is preferably designed to receive excess powder from an entire manufacturing process comprising a plurality of application processes up to the completion of one or more components.The overflow tank can be part of the conveyor system or part of the AM machine.

[0082] The intermediate container, in particular with the chain-driven conveyor, can preferably extend along one (entire) side of the construction container. The intermediate container can have an elongated, in particular flat, basic shape, wherein the intermediate container can be arranged relative to the construction container such that a longitudinal extension of the intermediate container is parallel to an (outer) wall of the construction container. Preferably, the intermediate container is arranged with its longitudinal extension substantially orthogonal to the working direction or movement direction of the coater.

[0083] The chain-driven conveyor can be implemented in various ways, although the invention is not limited to any specific design. The chain-driven conveyor can operate continuously or intermittently.

[0084] According to one embodiment, the conveying device can comprise a chain conveyor running along the longitudinal extent of the intermediate container. The chain conveyor can preferably have two (pulling) chains running continuously in a transport direction or conveying direction, each with an upper and a lower strand. It can preferably be designed as a scraper conveyor or a trough chain conveyor. Both allow the powdery material residue to be fed through the empty, returning upper chain strands onto the lower load strands. This allows the depth of the intermediate container to be fully utilized, particularly when the material residue is fed in a surge onto the conveying device.Alternatively, the chain conveyor can also be designed for bilateral removal of the remaining material. By placing a horizontal intermediate plate between the upper and lower strands over a portion of the length of the intermediate container, the upper strands in the area of ​​the intermediate plate also become load strands. While the scraper conveyor can transport the remaining material with flights (as conveying elements) attached to the revolving pull chains transversely to a conveying direction, the pull chains, including their crossbars and / or flights formed on them (as conveying elements), can run entirely within the conveying stream in the trough chain conveyor. This allows the trough chain conveyor to offer a particularly space-saving design.

[0085] A preferred chain conveyor can have four sprockets mounted in pairs on two shafts connected by two endless roller chains. Preferably, all four sprockets can then have inter-toothed areas with a previously described escape space. During additive manufacturing, particularly as a result of the removal of excess powder from the build area, the sprockets and chains are regularly charged with powder. Advantageously, even large quantities of powder can be reliably removed from the sprockets via the special sprockets, enabling smooth operation. This advantage, in combination with the space-saving design and the sufficiently large conveying capacity of the chain conveyor, can have a beneficial effect on the efficiency of the AM machine.

[0086] In principle, the chain conveyor can also be operated intermittently as a continuous conveyor. It can therefore be started as soon as a residual material is discharged into the intermediate container after a coating process. Once the intermediate container is completely empty, the conveyor system can be shut down, for example, if the time interval until the next residual material from a subsequent coating process is discharged is sufficiently long.

[0087] The chain-driven conveyor, preferably the chain conveyor, can have one or more conveying elements that can be moved in the intermediate container along its longitudinal extent, in particular in relation to an outlet opening of the intermediate container. Preferably, several conveying elements for powder, e.g. conveyor plates, can be attached at regular intervals to both chains of the chain conveyor. The conveying elements can be designed in the form of flights that are attached to the two roller chains transversely to a conveying direction. The flights can be guided over a base of the intermediate container (or just above it) in order to transport the powder in the conveying direction, e.g. in the direction of a destination, e.g. to an outlet opening. The outlet opening is preferably arranged at one end of the elongated intermediate container. One of the two shafts of the chain conveyor can preferably be arranged above the outlet opening.

[0088] According to one embodiment, the conveying device can have an alternately operated, chain-driven conveyor with at least one conveying element that can be moved alternately along the longitudinal extent of the intermediate container. The conveyor does not convey continuously, but rather at individual intervals. This makes it suitable for intermittent operation and for adjusting its conveying capacity during operation. The conveyor can have several carriers (as conveying elements) that can be moved back and forth in one conveying direction and in the opposite direction, which are arranged transversely in the conveying direction and rotatable by 90°. Because they run on the same track in both the conveying direction and the opposite direction, this conveyor requires less space in the intermediate container. This allows a larger area of ​​the intermediate container to be used to hold powder.

[0089] The conveyor can have a conveying element that can be moved alternately along the longitudinal extent of the intermediate container. The conveying element can extend horizontally and comprise slats that project downwards and are inclined in the conveying direction. The slats project into the residual material and push it in the conveying direction. In the opposite direction, the slats slide over the powdery residual material. The slats can also be perforated, e.g., frame-shaped. This allows the powder to pass through the slats when the conveying element moves in the opposite direction and not be transported. The scraper or slatted plate as the conveying element only needs to have a low overall height, which means that the space in the intermediate container is almost entirely available for receiving the residual material.

[0090] The conveying device can preferably comprise a drive with a coupling gear that is designed to drive the alternately operated chain conveyor, in particular the alternately movable conveying element, in a slow forward motion in the conveying direction and in a fast reverse motion in the opposite direction. This allows the conveying capacity to be increased by utilizing the inertia of the residual material. This is because in the slow-moving conveying direction, the residual material is set in motion completely. In the fast-moving opposite direction, however, the residual material remains largely motionless due to its inertia. The drive of the conveying device can alternatively or additionally comprise a coupling gear that is designed to lower the alternately operated chain conveyor, in particular the alternately movable conveying element, in the conveying direction and raise it in the opposite direction.This allows the slats to penetrate the remaining material in the conveying direction to transport it efficiently. In the opposite direction, however, the slats lift out of the remaining material to prevent it from moving. This gives the conveying element a more balanced movement profile while maintaining the same efficiency, resulting in less wear.

[0091] In principle, a combination of the funding principles described above is also possible in the funding institution.

[0092] With a flat design of the intermediate container, the build container can be removed from the AM machine underneath the intermediate container without the overflow container hindering the removal. This makes it possible to guide the build container through a protective gas lock before removal and to position the overflow container in a location within the device that is more easily accessible for the operator. The arrangement of the protective gas lock makes the device more cost-effective to operate, while the new arrangement of the overflow container certainly makes it more convenient to use.

[0093] The conveyor device can preferably be mounted or installed in the AM machine in such a way that the conveyor device, in particular the intermediate container, can be moved at least partially between a working position and a service position. For example, the conveyor device can be pivoted and / or displaced. For example, the build container of the AM machine can then be removed from the AM machine in a direction towards the working position of the intermediate container. During non-productive machine times, i.e. outside of a manufacturing process, the conveyor device, in particular the intermediate container, can be moved from the working position to the service position, e.g. upwards into an empty space in the process space. This can create (additional) space for removing the build container. This allows the conveyor device and / or the intermediate container to be larger than with a rigid conveyor device.

[0094] The AM machine can include a temperature lock to generate a temperature difference in the conveying system, in particular to generate a temperature difference between the intermediate container and the associated overflow container. Devices such as constrictions in a passage cross-section or strip curtains in the transport path between the intermediate container and the overflow container are suitable as temperature locks. This can reduce heating beyond the build container and the adjacent intermediate container.

[0095] Advantageously, a temperature lock can be used to achieve a difference between an average maximum temperature of the powder in the intermediate container and in the overflow container of at least 30°C, preferably at least 50°C, more preferably at least 100°C, and particularly preferably at least 200°C. A comparatively low temperature of the powder in the overflow container can have a beneficial effect on the degree of recycling.

[0096] The invention is explained in more detail below with reference to the accompanying figures using exemplary embodiments. In the various figures, identical components are provided with identical reference numerals. The figures are generally not to scale. They show:

[0097] Figure 1 is a schematic, partially sectioned view of an embodiment of an apparatus for additive manufacturing,

[0098] Figure 2 is a perspective view of parts of an additive manufacturing device with two conveyors according to the invention,

[0099] Figure 3 is a perspective and partly schematic view of parts of a conveyor device from Figure 2,

[0100] Figure 4 is a perspective view of part of a chain conveyor of the conveyor device of Figure 3,

[0101] Figures 5 to 7 show different views of sprockets according to the invention,

[0102] Figure 8 is a schematic view of part of a sprocket according to the invention,

[0103] Figures 9 to 11 show schematic views of parts of sprockets according to the invention. Figure 1 schematically describes a device 1 for additive manufacturing or an AM machine for producing components 2 in the form of a selective laser sintering or laser melting device 1. The invention is not limited to selective laser sintering or laser melting devices. The device 1 is referred to below—without limitation of generality—as laser sintering device 1.

[0104] The laser sintering device 1 has a process chamber 3 or a process space 3 with a chamber wall 4, in which the manufacturing process essentially takes place. Located within the process chamber 3 is a construction container 5, or simply a container 5, with a container wall 6. The upper opening of the container 5 forms the current working plane 7. The area of ​​this working plane 7 located within the opening of the container 5 can be used to build the object 2 and is therefore referred to as the construction field 8.

[0105] The container 5 has a base plate 11 which is movable in a vertical direction V and is arranged on a carrier 10. This base plate 11 closes off the container 5 at the bottom and thus forms its base. The base plate 11 can be formed integrally with the carrier 10, but it can also be a plate formed separately from the carrier 10 and fastened to the carrier 10 or simply mounted thereon. Depending on the type of specific construction material, for example the powder used, and the manufacturing process, a construction platform 12 can be attached to the base plate 11 as a construction base on which the object 2 is built. In principle, however, the object 2 can also be built on the base plate 11 itself, which then forms the construction base.

[0106] The basic construction of the object 2 takes place in that a layer of building material 13 is first applied to the construction platform 12, then - as explained later - with a laser beam 22 as an energy beam at the points which are to form parts of the object 2 to be manufactured, the building material 13 is selectively solidified, then with the help of the carrier 10 the base plate 11, thus the construction platform 12, is lowered and a new layer of the building material 13 is applied and selectively solidified, etc. In Figure 1, the object 2 built up in the container 5 on the construction platform 12 is shown below the working plane 7 in an intermediate state. It already has several solidified layers, surrounded by unsolidified building material 13. Various powders or mixtures of different powders can be used as the building material 13.Even though only a single component 2 is shown in Figure 1, it is possible and usually common practice to produce multiple objects in parallel in the process chamber 3 or container 5. For this purpose, the build material is scanned layer by layer by the energy beam at locations that correspond to the cross-sections of the objects in the respective layer.

[0107] Fresh build material 15 is arranged in a storage container 14 of the laser sintering device 1. Using a coater 16 movable in a horizontal direction H, the build material can be applied in the form of a thin layer in the working plane 7 or within the build area 8. Optionally, an additional radiant heater 17 is located in the process chamber 3 for heating the applied build material 13.

[0108] For selective solidification, the laser sintering device 1 has an irradiation device 20, or specifically an exposure device 20 with a laser 21. The laser 21 generates a laser beam 22, or energy beam 22, which is deflected by a deflection device 23, or a scanner 23, in order to traverse the exposure paths or tracks (hatch lines) provided according to the exposure strategy in the respective layer to be selectively solidified and to selectively introduce the energy. Furthermore, this laser beam 22 is appropriately focused onto the working plane 7 by a focusing device 24. The irradiation device 20 is located outside the process chamber 3, and the laser beam 22 is guided into the process chamber 3 via a coupling window 25 arranged on the top side of the process chamber 3 in the chamber wall 4.

[0109] The irradiation device 20 can, for example, comprise not just one but several lasers 21. These can preferably be gas or solid-state lasers or any other type of laser, such as laser diodes, in particular VCSELs (Vertical Cavity Surface Emitting Lasers) or VECSELs (Vertical External Cavity Surface Emitting Lasers), or a row of these lasers. Very particularly preferably, one or more CO and / or CO2 lasers can be used within the scope of the invention.

[0110] The laser sintering device 1 further contains a sensor arrangement 18 which is suitable for detecting process radiation emitted during the impact of the laser beam 22 on the build-up material 13 in the working plane 7. This sensor arrangement 18 operates with spatial resolution, i.e. it is capable of detecting a type of emission image of the respective layer. The sensor arrangement 18 can have an image sensor or a camera 18. Alternatively or additionally, one or more sensors could also be used to detect optical and / or thermal process radiation, e.g. photodiodes which detect the electromagnetic radiation emitted by a melt pool under the impact of a laser beam, or temperature sensors for detecting emitted thermal radiation (so-called melt pool monitoring). The signals detected by the sensor arrangement 18 can be stored as a process space sensor data set orLayer image is transferred here to a control device 30 of the laser sintering device 1.

[0111] The laser sintering device 1 has a control device 30, which also serves to control the various components of the laser sintering device 1 for the overall control of the additive manufacturing process. The control device 30 comprises a control unit 29, which controls the components of the irradiation device 20, namely the laser 21, the deflection device 23, and the focusing device 24, and transmits the corresponding irradiation control data BS to them.

[0112] The control unit 29 also controls the radiant heater 17 by means of suitable heating control data HS, the coater 16 by means of coating control data ST and the movement of the carrier 10 by means of carrier control data TS and thus controls the layer thickness.

[0113] The control device 30 is coupled, here, for example, via a bus 33 or another data connection, to a terminal 32 with a display or the like. Via this terminal 32, an operator can control the control device 30 and thus the entire laser sintering device 1, for example, by transmitting process control data PS.

[0114] The laser sintering device 1 has a purely schematically shown conveyor device 40, which is arranged in an intermediate container 41, also shown schematically. The intermediate container 41 and thus also the conveyor device 40 are arranged in the immediate vicinity of the construction area 8 and contact the container wall 6 of the construction container 5 from the outside. The conveyor device 40 or the intermediate container 41 can be arranged flush with the work plane 7 or slightly below it. Unlike the example shown here, a conveyor device 40 could also be assigned to the opposite (left) container wall 6.

[0115] During operation of the laser sintering device 1, the coater 16 distributes fresh build material, for example, starting at the left-hand container wall 6, across the build area 8 to the right-hand container wall 6. Excess build material, which is supplied, for example, as a reserve in front of the coater 16, is pushed by the coater 16 at the end of an application process beyond the right-hand container wall 6 into the intermediate container 41. The intermediate container 41 extends along one entire side of the build container 5, here along the entire right-hand chamber wall 6 shown in section.

[0116] The intermediate container 41 extends with its longitudinal extent parallel to the right-hand container wall 6 in the process chamber 3 and interacts with a purely schematically shown collecting container 42 to deliver the excess powder 13' discharged from the build container 5 by the coater 16 to the collecting container 42. Unlike the schematically shown here, the collecting container 42 can be further away from the build field 8.

[0117] Figure 2 shows a perspective view of parts of a laser sintering device 1 that are relevant to the invention. A build container 5 of the laser sintering device 1 is enclosed on two opposite sides 5' by a conveyor device 40 each. Since the conveyor devices 40 are constructed in a comparable manner, only the conveyor device 40 on the right will be described in more detail below. The conveyor device 40 has a trough-like intermediate container 41, with some components of the conveyor device 40 being arranged inside and other components outside the intermediate container 41. The intermediate container 41 is open at the top along a large part of its longitudinal extent LEFE (apart from a housing 45). Excess powder can enter the intermediate container 41 by gravity via this open upper side, which during operation preferably faces the coater of the AM machine.

[0118] The conveyor device 40 extends with its longitudinal extension LEFE, which corresponds to the longitudinal extension LEFE of the intermediate container 41, along a shorter side 5' of the construction container 5 and protrudes beyond it on both sides. The intermediate container 41 directly contacts the construction container 5 (laterally), with an upwardly facing upper edge 4T of the intermediate container 41 being arranged slightly below an opening of the construction container 5.

[0119] A chain conveyor 50 is arranged in the intermediate container 41, wherein a longitudinal extension of the chain conveyor 50 corresponds to a longitudinal extension LEFE of the intermediate container 41.

[0120] To move the chain conveyor 50, the conveyor device 40 comprises a controllable drive 40', which is arranged on a housing 45 at an end region of the conveyor device 40. The housing 45 closes off the intermediate container 41 at one end and contains, for example, drive components of the chain conveyor 50, in particular a shaft of the chain conveyor 50. The housing 45 forms a downwardly facing, funnel-shaped housing region, which is provided for introducing the excess powder, which is discharged by the chain conveyor 50 from an outlet opening (not visible) of the intermediate container 41, via connecting pipes 44 into an overflow container 42. The overflow container 42 or collecting container 42 is here a component of the laser sintering device 1.

[0121] Figure 3 shows parts of the conveyor device 40 from Figure 2 in an enlarged perspective and partly schematic view. The chain conveyor 50 is arranged in the elongated intermediate container 41 such that a longitudinal extension of the chain conveyor 50 corresponds to a longitudinal extension LEFE of the intermediate container 41 or a longitudinal extension LEFE of the conveyor device 40. The chain conveyor 50 comprises two endlessly circulating parallel roller chains 63, 63'. The roller chains 63, 63' each engage with two sprockets (as gears), with two sprockets each arranged on a common shaft 68. The shafts 68 are each arranged at opposite ends of the intermediate container 41. In Figure 3, only one shaft 68 is visible, the second shaft being arranged in the housing 45 and being rotatable by the drive 40'.The chain conveyor 50 is designed such that at least the roller chains 63, 63' and the conveyor plates 43 located thereon are arranged within the intermediate container 41, ie they do not protrude beyond the upper edge 4T.

[0122] Conveyor plates 43 are mounted at regular intervals as conveyor elements 43 between the two roller chains 63, 63'. The conveyor plates 43 have a rectangular basic shape in cross-section and can be designed as angled plates with an L-profile. During operation, the (lower) conveyor plates 43 can be guided over a base plate 46 of the intermediate container 41 in a direction of movement BR to transport excess powder 13' in the intermediate container 41. The direction of movement BR preferably corresponds to the conveying direction of the powder 13'. The powder 13' is shown here purely schematically. For example, the conveyor plates 43 can rest with a narrow side of a leg on the base plate 46, with the powder 13' being pushed in front of the respective conveyor plates 43 on the base plate 46 in the direction of movement BR. Accordingly, the chain conveyor 50 has load strands located underneath.

[0123] In the housing 45, the powder 13' can be discharged from the intermediate container 41 through an outlet opening (not shown) and thus leave the conveyor device 40. Preferably, a second shaft of the chain conveyor 50 is mounted above the outlet opening and / or behind the outlet opening with respect to the direction of movement BR. After being deflected via the second shaft, the conveyor plates 43 are returned to the opposite end of the intermediate container 41 by the two roller chains 63, 63', lying on top, against the direction of movement BR.

[0124] Figure 4 shows a part of the chain conveyor 50 from Figure 3 in detail, although the other components of the conveyor device are not shown. The two chain wheels 51 are visible, which are arranged on the shaft 68. The chain wheels 51 can, for example, be firmly connected to the shaft 68. It is also possible for the chain wheels 51 to be implemented as part of the shaft 68. Furthermore, it can be seen that the conveyor plates 43 (as conveyor elements 43) each form a type of L-profile. A guide plate 67 is arranged between the lower part of the front roller chain 63' (as the load strand) and the upper part of the same roller chain 63' in order to maintain a certain distance between the upper and lower chain strands during operation. The upper chain strand here rests on top of the guide plate 67 and is in contact with it via rollers (not shown) of the roller chain 63'.The guide plate 67 can also serve to wipe off any powder deposits on the upper chain strand. The two roller chains 63, 63' have outer chain links 69 and connected inner chain links 69'. The rollers of the roller chains 63, 63' are not shown here. The two roller chains 63, 63' can be constructed like known roller chains. Unlike shown here, the roller chains 63, 63' are designed as endlessly circulating roller chains 63, 63' during operation (some chain links have been omitted in the figure to ensure visibility of other parts).

[0125] Figure 4 shows that the two sprockets 51 have different sprocket sides 53, 53'. An outward-facing sprocket side 53' (facing away from the other sprocket on the same shaft) has a number of escape spaces 54 for powder, as described in more detail below. In contrast, an opposite inward-facing sprocket side 53 is flat in this embodiment, i.e., without escape spaces. The two sprockets 51 of a respective shaft 68 can preferably be identical (e.g., only laterally rotated).

[0126] Figure 5 shows a perspective view of a sprocket 51, e.g., from Figure 4, in detail, showing a sprocket side 53' with escape spaces 54, 54' for powder. The opposite, less visible sprocket side can preferably be flat or planar, e.g., as shown in Figure 4. It can also be seen that part of the sprocket 51 is formed by the shaft 68. The sprocket 51 comprises a plurality of teeth 57, 57', which are arranged evenly distributed over a circumference of the sprocket 51. The area of ​​the sprocket 51 that lies between two adjacent teeth 57, 57' forms an intermediate tooth area 52 (In order to be able to better distinguish between two adjacent teeth 57, 57' and escape spaces 54, 54' in the description, slightly different reference numbers 57, 57', 54, 54' are arbitrarily assigned to some of the different teeth and escape spaces, although the teeth 57, 57' and escape spaces 54, 54' are each constructed identically).In the example shown here, the sprocket 51 has nine separate intermediate tooth regions 52, each separated by a tooth 57, 57'. Due to the perspective view and for clarity, only one intermediate tooth region 52 is provided with a reference symbol.

[0127] An intermediate tooth region 52 begins here at a lower end of a tooth flank 60 of a first tooth 57 and extends to the beginning of an opposite tooth flank 60 of an adjacent, second tooth 57'. In this example, the intermediate tooth region 52 comprises a tooth base 56 between these two adjacent teeth 57, 57'. Accordingly, the tooth base 56 connects the tooth flank 60 of the first tooth 57 with the facing tooth flank 60 of the second tooth 57'. Unlike the example shown here, the intermediate tooth region 52 and the tooth base 56 could also have different dimensions.

[0128] The tooth base 56 between the first tooth 57 and the second tooth 57' forms a slip-off surface 55 as an escape space 54 for powder. In this example, the slip-off surface 55 forms a slip-off plane 58 for powder. The slip-off plane 58 begins in or at the tooth base 56, in particular starting from a tooth base upper side 56', and extends in the direction of the shaft 68 or in the direction of a sprocket center point 59 (Figure 6). Figure 5 shows that the slip-off plane 58 is tongue-shaped, in particular a region of the slip-off plane 58 facing the shaft 68. Furthermore, it is shown that the slip-off plane 58 extends along the entire longitudinal extent of the tooth base 56. This means that the slip-off plane 58 extends from the tooth flank 60 of the first tooth 57 to the tooth flank 60 of the adjacent second tooth 57'.

[0129] The slip-off plane 58 is formed by a clearance in the tooth base 56 of the sprocket 51. This reduces the width of the tooth base 56 (parallel to the shaft 68), in particular the width of the tooth base top surface 56', compared to known sprockets. The clearance in the tooth base 56 or the slip-off plane 58 in the intermediate tooth area 52 results in a certain portion of the tooth base 56, in particular the tooth base top surface 56', being replaced by a material-free space.

[0130] Such a narrow tooth base top surface 56' advantageously allows the contact area between the gear 51 and a chain to be kept as small as possible. Figure 5 schematically shows a single chain roller 64 of a roller chain, wherein the chain roller 64 is in engagement with the chain wheel 51. It is schematically shown that the chain roller 64 directly contacts or rests on the gear 51 only in the region of the tooth base top surface 56'. In the region of the slip-off plane 58', the chain roller 64 is spaced from the slip-off plane 58' during operation.

[0131] The sliding plane 58' is arranged obliquely with respect to its longitudinal extension relative to a tooth longitudinal extension LEZA of an adjacent tooth 57'. This allows powder that strikes the sliding plane 58' to slide off it by gravity. Furthermore, the inclination of the sliding plane 58' can help deflect powder that rests on the tooth base 56 or on the tooth base top surface 56', unless the chain roller 64 is actually resting on the respective tooth base 56.

[0132] The slipping planes 58, 58' between the adjacent teeth 57, 57' are each identical in Figure 5. However, it would also be possible that on the same sprocket

[0133] 51 different slipping levels 58, 58' or alternative spaces 54, 54' are arranged.

[0134] In Figure 6, a chain wheel 51 according to the invention is shown in a different view, e.g. the chain wheel 51 from Figure 5. It can be seen that the respective intermediate tooth area

[0135] 52 is dimensioned identically here to the associated tooth base 56 (relative to the longitudinal extent). The tooth base 56 connects the opposite tooth flanks 60 of two adjacent teeth 57, 57'. A longitudinal tooth extension LEZA is shown schematically using a middle tooth 57' (upper in the figure), wherein the tooth 57' comprises a tooth tip 56'" and a tooth root 56". The tooth 57' is connected to the wheel body of the sprocket 51 via the tooth root 56".

[0136] The wheel body (not shown in detail here) denotes the sprocket 51 without the teeth 57, 57' arranged on the outside. The wheel body has a circular circumference and is defined by a specific radius R, which is based on the root diameter Df. The sprocket 51 can preferably be designed such that a specific ratio is achieved between a longitudinal extension LEi of a slip surface 55 and a tooth longitudinal extension LEZA of an associated tooth 57'. It is also possible to achieve a specific ratio between a longitudinal extension LEi of a slip surface 55 and the radius R and / or the root diameter Df.

[0137] The teeth 57, 57' can be comparatively large, as shown in Figure 6, with a longitudinal extension LEZA each being approximately one-fifth of the root diameter Df. Figure 6 also shows a gear wheel center 59 and a sprocket wheel center 59, respectively.

[0138] Figure 7 shows a section through a sprocket 51 according to the invention. It can be seen that the sprocket side 53' facing in the viewing direction has an escape space 54, 54' for powder between two teeth 57, 57', or a respective slip-off plane 58, 58'. The opposite sprocket side 53 has no such escape spaces 54. Accordingly, a vertical, flat surface adjoins the tooth base top surface 56', which is approximately parallel to the tooth longitudinal extension LEZA of the associated tooth 57' or essentially orthogonal to a rotational axis of the shaft 68.

[0139] The sliding surface 55' or sliding plane 58' is arranged obliquely with respect to the longitudinal tooth extension LEZA of the associated tooth 57' with respect to its longitudinal extension LEi. The sliding surface 55' or sliding plane 58' is inclined with respect to the longitudinal tooth extension LEZA, forming a specific angle α. The angle α is shown schematically here with respect to the opposite sprocket side 53, wherein the corresponding surface is essentially parallel to the longitudinal tooth extension LEZA. The sliding surface 55' or sliding plane 58' forms an inclined, inherently flat sliding surface for the powder impacting from above. In principle, however, the sliding plane does not have to be essentially flat as here, but could, for example, also be curved transversely to the radial direction (e.g. concave), in particular slightly curved, i.e. with a large radius of curvature.

[0140] In Figure 7 it can be seen that a material cross-section MQ of the sprocket 51 in the intermediate tooth area tapers from the shaft 68 to the tooth base top side 56'.

[0141] Figure 9 shows a part of a cross-section of the chain wheel 51 parallel to its axis of rotation, whereby the section shown here corresponds to the area of ​​the upper part of the cross-section in the foreground in Fig. 7 (only here with a slightly different design of the slipping surface). In Fig. 9, HO denotes a height of the slip surface 55 in a direction perpendicular to the axis of rotation of the gear 51, LER an axis which also runs perpendicular to the axis of rotation and which intersects an edge between the tooth base top side 56' and the longitudinal extension LEi of the slip surface 55, MQ' a length of a projection of the slip surface 55 or the longitudinal extension LEi onto an axis parallel to the axis of rotation of the sprocket 51 (MQ' also corresponds to the difference between the material cross-section MQ of the sprocket 51 and the width of the tooth base top side 56') and a the angle between the longitudinal extension LEi and the axis LER (this definition is analogous to the definition of a in the description of Fig. 7).For the basic shape of the interdental space shown, it is sufficient to specify two of the three design parameters HO (height), LEi (longitudinal extension), and a (angle) so that the third is necessarily specified. For a specific width of the tooth base top surface 56', two of the design parameters HO (height), LEi (longitudinal extension), a (angle), MQ (material cross-section), and / or MQ' (difference between the material cross-section MQ and the width of the tooth base top surface 56') can be specified so that the others are necessarily specified.

[0142] Preferably, the inclination of the longitudinal extent LEi of the sliding surface 55 is sufficient so that the powder that strikes the sliding surface 55 slides, for example by gravity, along the sliding plane 58 and can be carried away from the inter-tooth region. This means that the angle α is as small as possible, compatible with the other design parameters, in particular with the height HO and / or with the material cross-section MQ and / or with the material cross-section MQ'. Although both Fig. 7 and Fig. 9 show a single inclination angle α, the sliding plane 58 or the sliding surface 55 can have several different inclination angles. So that a free end of the sliding surface 55 is as steep as possible, the sliding plane 58 or the sliding surface 55 can, for example, be divided into two radial sections 80a, 80b, each having different inclination angles.In Figure 9, this alternative variant is indicated by a dotted line, which symbolizes the surface profile of a radially inner section 80b of the sliding surface, which adjoins a radially outer section 80a of the sliding surface coming from the tooth base top side 56' at a kink 81. In the example shown, this radially outer section 80a again has the angle of inclination a to the axis LER, and from the kink, the sliding surface 55 in the inner radial section 80b then has a smaller angle of inclination, i.e., the sliding surface 55 is steeper here. Thus, the height of the sliding surface 55 is also greater here than in the first variant. This can facilitate the sliding or removal of the powder. In principle, however, the angle of inclination could also be greater in the radially inner section of the sliding surface 55, i.e.The slip surface 55 is steeper at the top surface 56' of the tooth base and becomes flatter towards the inside if this would be more constructively sensible in the individual case. However, a steeper radially inner end is usually preferred.

[0143] Fig. 10 shows a part of a cross-section of an alternative sprocket 51 parallel to its axis of rotation, in particular again an upper part of a cross-section which intersects the sprocket 51 at a position between two teeth 57, 57' (Fig. 7), i.e. at the position of a slip-off surface 55. Unlike in Fig. 7 and Fig. 9, here a circular (circular arc-like) slip-off plane 58 forms the slip-off surface 55. The slip-off plane 58 here runs in the radial direction of a circular arc profile 78 with a radius of curvature KR. This radius of curvature KR determines the curvature or steepness of the slip-off plane 58. For comparison, an alternative circular arc profile 78' with a smaller radius of curvature KR' is shown in Fig. 10 with a dotted line. As can be seen from the illustration in Fig. 10, a free end (here pointing to the left) of the slipping surface 55 ora sliding surface end that follows the circular arc profile 78 with the larger radius of curvature KR is steeper than the area of ​​the sliding surface 55 that follows the circular arc profile 78' with the smaller radius of curvature KR'. A steeper sliding surface end is advantageous because it can facilitate the sliding of the powder that impacts the sliding surface 55 along the sliding plane 58. Therefore, in most cases, a circular (circular arc-like) sliding plane 58 forming the sliding surface 55 is preferably realized with the largest possible radius of curvature (compatible with other design parameters such as a gear wheel width). Furthermore, the greatest possible height of the sliding plane 58 is advantageous. As shown in Fig. 10, the height HO corresponding to the larger radius of curvature KR is greater than a height HO' corresponding to the smaller radius of curvature KR'.A large radius of curvature KR and a large height of a slipping surface 55 can be compensated by a wide tooth base top surface 56' or can be structurally compatible with a wide tooth base top surface 56'.

[0144] Fig. 11 again shows an upper part of a cross-section of a further alternative sprocket 51 at a position between two teeth 57, 57' (Fig. 7), i.e. again a cross-section through a slipping surface 55 of this sprocket 51. Unlike in Fig. 7, Fig. 9 and 10, in Fig. 11 a curved, but non-circular slipping plane 58 forms the slipping surface 55. In particular, in Fig. 11 the slipping surface 55 is formed by a slipping plane 58 that is parabolic in the radial direction. Although a parabolic slipping plane 55 is shown in Fig. 11, other curved, non-circular slipping planes are conceivable, such as a hyperbolic or an elliptical slipping plane.

[0145] To illustrate the effect of the precise shape, two alternative two-dimensional parabolic arc profiles 79, 79' are sketched in Fig. 11 to define the course of such a parabolic slip plane, each forming a slip surface. A first parabolic arc profile 79, which the slip plane shown in section (in solid line) in Figure 10 follows in the radial direction, is a section of an (imaginary) parabola emanating from a (virtual) origin U that lies outside the material cross-section of the sprocket. The alternative second parabolic arc profile 79', shown here only in dotted lines, is, in contrast, a section of an (imaginary) parabola emanating from a (virtual) origin U' that lies on an axis LERI that is perpendicular to the axis of rotation of the sprocket 51 and that lies in a plane corresponding to the sprocket side 53'. The origin U' is therefore closer to the LER axis than the origin U.

[0146] As can be seen from the illustration in Fig. 11, a radially outer free end of the slip surface (free slip surface end), which corresponds to the parabolic arc profile 79 with the origin U further away from the sprocket, is steeper than the free end of a slip surface corresponding to the parabolic arc profile 79'. A steeper free slip surface end is advantageous because it can facilitate the sliding of the powder that impacts the corresponding partial area of ​​the slip surface 55 along the slip plane 58. Advantageously, a curved, non-circular (e.g., parabolic, hyperbolic, or elliptical) slip plane forming the slip surface can therefore be realized such that its origin (compatible with other design parameters such as the width of the sprocket) is as far away as possible from the axis LER. Furthermore, it can be advantageous if the origin U is lower than the rotational axis of the sprocket 51.This makes it easier for the powder to glide or be carried away.

[0147] Figure 8 shows a purely schematic view of part of a sprocket 51 according to the invention. Between two adjacent teeth 57, 57', a chain roller 64 of a chain is shown, which is in engagement with the sprocket 51. The intermediate tooth region 52 here comprises a clearance 61 as an escape space 54 for powder. The clearance 61 is designed such that the engaged chain roller 64 is spaced a distance a from a wheel body 62 of the gear 51. The chain roller 64 is supported on the two opposite teeth 57, 57' only via two contact regions 65, 65', each contact region 65, 65' being formed by a tooth 57, 57'. The contact regions 65, 65' are arranged on the respective tooth flanks 60, in particular in a convex section.

[0148] In this embodiment, the chain roller 64 rests on the sprocket 51 only via two narrow, elongated contact surfaces 65, 65' in the area of ​​the teeth 57, 57'. In the area of ​​the intermediate tooth space 52, in particular between the two contact areas 65, 65', there is no direct contact between the chain roller 64 and the (remaining) sprocket 51 during operation. In this example, the clearance 61 is designed as a material-free space such that the intermediate tooth area 52 is formed without a tooth base. A width b of the intermediate tooth area 52 is smaller by a certain amount than an outer diameter D of the roller chain 64. The clearance 61 in the intermediate tooth area 52 makes it possible to ensure that the resting chain roller 64 is spaced apart from powder 13' present in the intermediate tooth area 52.

[0149] Finally, it should be pointed out once again that the conveyor devices described in detail above are merely exemplary embodiments which can be modified in a variety of ways by a person skilled in the art without departing from the scope of the invention. For example, the escape spaces of the sprockets shown in the respective exemplary embodiments can be exchanged and / or combined with one another as desired. The sprockets could also have a slip-off surface or slip-off planes in the intermediate tooth regions on the other side, for example on the “inner” side facing the other second sprocket arranged on the same shaft in the figures. Likewise, the sprockets could also have slip-off surfaces or slip-off planes on both sides in the intermediate tooth regions.Have slippage planes, so that the top surface of the tooth base is shifted more toward the center parallel to the gear's rotational axis, allowing the powder material to slide off the top surface of the tooth base on both sides. Furthermore, the use of the indefinite articles "ein" or "eine" does not preclude the possibility that the respective features may be present multiple times. List of reference symbols.

[0150] 1 device for additive manufacturing / laser sintering device

[0151] 2 Component / Object

[0152] 3 Process room / process chamber

[0153] 4 chamber wall

[0154] 5 construction containers / containers

[0155] 5' page

[0156] 6 Container wall

[0157] 7 Working level

[0158] 8 Construction site

[0159] 10 carriers

[0160] 11 Base plate

[0161] 12 Construction platform

[0162] 13, 13' construction material

[0163] 14 storage containers

[0164] 15 Construction material in the storage container

[0165] 16 coaters

[0166] 17 Radiant heating

[0167] 18 Sensor arrangement / camera

[0168] 20 Irradiation device / exposure device

[0169] 21 lasers

[0170] 22 Laser beam / energy beam

[0171] 23 Deflection device / scanner

[0172] 24 Focusing device

[0173] 25 coupling windows

[0174] 29 Control unit

[0175] 30 Control device

[0176] 32 Terminal

[0177] 33 buses

[0178] 40 conveyor system

[0179] 40' drive

[0180] 41 intermediate containers

[0181] 41 ' top edge

[0182] 42 overflow tank / collection tank

[0183] 43 Conveyor element / conveyor plate 44 Connecting pipes

[0184] 45 housings

[0185] 46 floor panel

[0186] 50 Chain-driven conveyor / chain conveyor

[0187] 51 Gear / sprocket

[0188] 52 Interdental area

[0189] 53, 53' sprocket side

[0190] 54, 54' escape room

[0191] 55, 55' slide area

[0192] 56 Tooth base

[0193] 56' tooth base top

[0194] 56" tooth base

[0195] 56'“ tooth head

[0196] 57, 57' teeth

[0197] 58, 58' slide level

[0198] 59 Gear center / sprocket center

[0199] 60 tooth flank

[0200] 61 Exemption

[0201] 62 wheel bodies

[0202] 63, 63' chain / roller chain

[0203] 64 chain roller

[0204] 65, 65' contact area

[0205] 67 guide plate

[0206] 68 Wave

[0207] 69 Outer link

[0208] 69' inner link

[0209] 78, 78' Two-dimensional circular arc profile

[0210] 79, 79' Two-dimensional parabolic arch profile

[0211] 80a, 80b radial sections

[0212] 81 Bend a Angle a Distance b Width

[0213] BS irradiation control data

[0214] BR Direction of movement D Diameter of chain roller

[0215] Df diameter of root circle

[0216] H Horizontal direction

[0217] HS heating control data

[0218] HO, HO' Height of the slide level

[0219] KR, KR' radius of curvature

[0220] LEi Longitudinal extension

[0221] LEFE Longitudinal extension

[0222] LEZA tooth length extension

[0223] LER, LERI axis

[0224] MQ, MQ' material cross-section

[0225] PS process control data

[0226] R radius wheel body

[0227] ST coating control data

[0228] TS carrier tax data

[0229] V Vertical direction

[0230] U, LT origin

Claims

Patent claims 1. Conveying device (40) for a device (1) for the additive manufacturing of at least one component (2) from a powdered building material (13, 13', 15) by selectively at least partially solidifying the building material (13), wherein the conveying device (40) for conveying building material (13') in the device (1) has a chain-driven conveyor (50), preferably a chain conveyor (50), with at least one gear (51), wherein at least one intermediate tooth region (52) between two adjacent teeth (57, 57') of the gear (51) comprises an escape space (54, 54') for the powdered building material (13').

2. Conveying device according to claim 1, wherein the gear wheel (51) has two or more spaced-apart, preferably different, escape spaces (54, 54') for the building material (13'), and / or wherein the escape space (54, 54') for the building material (13') comprises a clearance (61) in the intermediate tooth region (52).

3. Conveying device according to claim 1 or 2, wherein the escape space (54, 54') has a sliding surface (55, 55') for guiding building material (13') away from the intermediate tooth region (52).

4. Conveyor device according to claim 3, wherein the slipping surface (55, 55') is formed by a tooth base (56) between two adjacent teeth (57, 57'), wherein preferably the slipping surface (55, 55') connects two adjacent teeth (57, 57') to one another.

5. Conveyor device according to claim 3 or 4, wherein the gear (51) for forming the slipping surface (55, 55') has a material cross-section (MQ) which tapers towards the tooth base (56).

6. Conveyor device according to one of claims 3 to 5, wherein the gear (51) for forming the sliding surface (55, 55') has one of the following elements: - at least one slipping plane (58, 58') extending from the tooth base (56) and arranged obliquely to a tooth longitudinal extension (LEZA), - at least one curved, in particular concave, slipping plane (58, 58') extending from the tooth base (56), - at least two optionally curved slipping planes (58, 58') extending from the same tooth base (56), which are arranged obliquely to a tooth longitudinal extension (LEZA) while forming a specific angle to one another.

7. Conveying device according to one of claims 4 to 6, wherein a tooth base upper side (56') of the tooth base (56), which faces away from a gear center (59), is at least partially concave.

8. Conveyor device according to one of claims 3 to 7, wherein a ratio between a longitudinal extent (LEi) of the sliding surface (55, 55') and a longitudinal extent (LEZA) of an associated tooth (57, 57') is at least 1:2, preferably at least 1:1.5 and / or at most 1:0.25, preferably at most 1:0.5, and / or wherein a ratio between a longitudinal extent (LEi) of the sliding surface (55, 55') and a radius (R) of a wheel body (62) of the gear wheel (51) is at least 1:10, preferably at least 1:5 and / or at most 1:1.5, preferably at most 1:

2.

9. Conveyor device according to one of the preceding claims 2 to 8, wherein the escape space (54, 54') for the building material (13') comprises a clearance (61) which is designed such that a certain distance (a) is formed between a chain roller (64) of a chain (63) in engagement with the chain wheel (51) and a tooth base (56).

10. Conveyor device according to one of the preceding claims 2 to 9, wherein the escape space (54, 54') for the building material (13') comprises a clearance (61) which is designed such that a chain (63) engaging with the chain wheel (51) is supported on two opposite teeth (57, 57') via two contact areas (65, 65'), in particular while leaving a distance (a) between a chain roller (64) of the chain (63) and a wheel body (62) of the gear wheel (51).

11. Conveyor device according to one of the preceding claims, wherein the conveyor device (40) has a preferably trough-like intermediate container (41) for receiving building material (13'), wherein the chain-driven conveyor (50) acts in the intermediate container (41), preferably being arranged at least partially therein.

12. Conveying device according to claim 11, wherein the chain-driven conveyor (50) has at least one conveying element (43) which is arranged in the intermediate container (41) along its Longitudinal extension (LEFE), optionally alternating, can be moved, in particular in relation to an outlet opening of the intermediate container (41).

13. Device (1) for the additive manufacturing of at least one component (2) with a feed device (16) for feeding a powdered building material (13, 13', 15) into a process space (3), an irradiation device (20) for selectively at least partially solidifying the building material (13) by irradiation with at least one energy beam (22) and a conveying device (40) according to one of the preceding claims.

14. Device according to claim 13, wherein the conveyor device (40) is designed to carry unused building material (13') away from a construction field (8) in the process space (3), in particular for conveying building material (13') from an intermediate container (41) of the conveyor device (40) into an overflow container (42), and / or wherein the conveyor device (40) is at least partially movable between a working position and a service position, and / or wherein the device (1) comprises a temperature lock for generating a temperature difference in the conveyor device (40).

15. Method for the additive manufacturing of at least one component (2), preferably in a device (1) according to claim 13 or 14, comprising the following steps: Feeding a powdered build-up material (13, 13', 15) into a process chamber (3), preferably by applying build-up material (13) layer by layer onto a build-up area (8), Irradiating the building material (13) with at least one energy beam (22) in order to selectively at least partially solidify the building material (13), Conveying building material (13') by means of a conveying device (40) which has a chain-driven conveyor (50), preferably a chain conveyor (50), with at least one gear (51), wherein at least one intermediate tooth region (52) between two adjacent teeth (57, 57') of the gear (51) comprises an escape space (54, 54') for the powdered building material (13'), preferably transferring excess building material (13') into an intermediate container (41) of the conveying device (40) and moving the building material (13') by means of the conveying device (40) from the intermediate container (41) into an overflow container (42) which is assigned to the conveying device (40).

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