Method for dispensing powder from an intermediate container of a powder bed fusion apparatus and corresponding apparatus

Abstract

A metering feeder for a powder fusion apparatus includes a powder inlet, a powder outlet (53), and a powder support (55). The powder inlet is configured to receive powder from a discharge opening of a powder hopper (20), the powder outlet (53) is configured to release powder into a recoater container (65) of the powder fusion apparatus (1), and the powder support (55) is located between the powder inlet and the powder outlet and configured to convey powder from the powder inlet to the powder outlet. When the powder support is coupled to an ultrasonic transmitter (57) and / or a vibration driver (57), the metering feeder enables the dispensing of powder from the powder hopper (20) to the recoater container (65) with high precision.

Description

Technical Field

[0001] This invention relates to additive manufacturing, also commonly referred to as 3D printing. More specifically, this invention provides an improvement to a powder bed fusion process, a corresponding powder distributor, and a powder bed fusion apparatus with the distributor. Background Technology

[0002] Additive manufacturing is an increasingly important method for creating 3D workpieces. Various variations of additive manufacturing exist, but in this paper we focus on methods and apparatus for joining powder particles by selectively heating the particles, for example, selectively heating the particles on top of a powder particle bed to cause some particles within the bed to adhere to each other. The powder particles adhere to each other through sintering, fusion, and / or welding. The heat used for these processes is typically provided by preferably focused radiation, such as by an electron beam or a laser beam, selectively heating a portion of the top layer of the powder bed, thereby attaching the particles of the top layer to the particles of the previous layer as well as to adjacent particles in the top layer. This process is commonly referred to as powder bed fusion or simply powder fusion. In this paper, we will not distinguish between different types of radiation and will simply refer to them as “beams” or “beams”.

[0003] Modern equipment for powder bed fusion has a housing with a processing chamber. The processing chamber has a support opening to accommodate a movable workpiece support. Initially, a thin layer of powder is applied to the workpiece support. This is primarily accomplished by a recoater. The recoater is a transport vehicle that travels back and forth at its bottom above the opening, thus coating the workpiece support with the powder layer. Recoats have been described in numerous published texts, and only a few examples are given, for instance, in WO2018 / 156264A1, WO2017 / 143145A1, EP1234625A, and DE102006056422B3. These recoats can be very roughly divided into two groups:

[0004] (i) Powder is supplied to the bottom of the processing chamber, for example through an opening next to the support opening, and subsequently dispensed by a dispenser. This dispenser, referred herein as a “type (i) recoater,” typically has at least one of a scraper, roller, lip, or similar component, configured to travel over the support opening to form a new powder layer over the workpiece support.

[0005] (ii) The powder container is movably supported to travel over the support opening, thereby applying a new powder layer over the workpiece support (“(ii) type recoater”). Typically, the (ii) type recoater also includes one or more dispensers for planing the powder layer, or in other words, for segmenting the powder layer. In this document, we refer to the container of the recoater as the “recoater container” and the “recoater container”.

[0006] Once a new powder layer has been applied, at least one beam moves over the top layer of the coated surface, causing some powder particles to adhere to each other and, in some cases, to the workpiece support. The workpiece support is then lowered, and a recoater applies the next layer of powder. The next layer is also subjected to a beam to selectively adhere powder particles to each other and to the structure of previously adhered particles. The process of lowering the workpiece support, applying a new powder layer, and laser “writing” is repeated to obtain a 3D object. This process has been described in several published texts, to name just two examples, such as those in US2017 / 0001243A1 and US9,061,465B2.

[0007] DE102004022387A1 discloses a recoater for a powder bed fusion apparatus, which has a circular scraper for dispensing powder. The circular scraper surrounds and in this sense comprises a grid of linearly extending scrapers. A new powder layer is applied by pushing the powder over an opening in a support using the circular scraper. As taught in DE102004022387A1, the circular scraper cuts off particulate agglomerates, which reportedly provides a denser powder layer with reduced roughness. To further improve the density of the powder layer, it is suggested that the circular scraper be coupled to an ultrasonic generating component.

[0008] DE10117875C1 recommends applying a new layer during powder bed fusion using a type (ii) recoater, which has a scraper to provide a thin, uniform powder layer. The scraper is rotatably supported and driven to perform rotational vibration. In operation, powder is conveyed from a powder hopper to the recoater container. The powder is deposited from the recoater container in front of the rotating, vibrating scraper, and pushed over the existing powder bed using a rotational vibration driver. This rotational vibration is intended to break up particulate agglomerates in the powder and homogenize the powder while applying a thin powder layer.

[0009] Regardless of whether the recoater is type (i) or type (ii), powder is dispensed from the intermediate container (also called the hopper) to the bottom of the processing chamber (in the case of using a type (i) recoater) or to the container of a type (ii) recoater. In currently used powder bed fusion equipment, the dispensing of powder from the intermediate container to the container of the recoater is achieved by a rotary feeder. (Please consider this to include the case where it is dispensed to the bottom of the processing chamber. The location where the powder is dispensed from the hopper can be considered as the container of the recoater forming a type (i) recoater).

[0010] The rotary feeder has an elongated "feed wheel," which can be considered a feed shaft. The feed shaft extends across the width of the support opening. The feed shaft has one or more notches extending along its axis of rotation. As the notches face upwards toward the downward-facing discharge opening of the intermediate container, powder slides into the volume of the notches. Rotation of the shaft causes the notches to face downwards, thus emptying them, i.e., pouring the powder from the notches into the container of the recoater. In other words, each rotation of the notches is intended to deliver a predetermined amount of powder into the container of the recoater. Summary of the Invention

[0011] This invention is based on the observation that the notches of the supply shaft in current powder bed fusion equipment must be manufactured through milling and grinding, resulting in high costs. Furthermore, the supply shaft is difficult to seal as needed to reduce leakage of inert gas from the processing chamber and the fall of powder particles. In addition, the dosage of the dispensed powder can only be adjusted in integer multiples of the notch volume and is also affected by powder bridging, which forms above a portion of the outlet of the intermediate container. Based on these observations, the object of this invention is to improve the container loading of the recoater in powder bed fusion equipment.

[0012] The solution to the problem is described in the independent claims. The dependent claims relate to further improvements to the invention.

[0013] For example, the problem briefly described above can be solved by a dosing feeder for a powder fusion apparatus. The dosing feeder may include a powder inlet. Through the powder inlet, the dosing feeder can receive powder from a discharge opening of a powder hopper. In practice, these powder hoppers are located inside a processing chamber, or at least have discharge openings that connect the storage volume of the hopper to the processing chamber. "Connected" in this context means enabling the transfer of powder from the hopper to the processing chamber. A hopper is an intermediate powder container in a powder supply system. In this document, we use the terms "hopper" or "powder hopper" only for linguistic distinction between the container of a recoator and an intermediate container (= hopper). In other words, without altering the technical teachings of this application and the patents granted by this application, the terms "powder hopper" and "hopper" can be replaced with "intermediate powder container."

[0014] In summary, the metering feeder is configured to receive powder from the hopper. For example, the powder inlet of the metering feeder can be located directly below the discharge opening of the hopper, thereby allowing powder to be supplied to the powder inlet of the metering feeder by allowing powder to fall downward from the discharge opening of the hopper.

[0015] The metering feeder has a powder outlet configured to release powder into the recoater container of the powder fusion apparatus. The recoater container may be an appliance of a type (ii) recoater or simply located on the base plate (i) of the processing chamber from which powder is dispensed by a type (i) recoater.

[0016] Between the powder inlet and the powder outlet of the metering feeder is a powder support. The powder support is configured to receive powder via the powder inlet and also to convey the powder to the powder outlet. As its name suggests, the powder support supports the powder; that is, it holds the powder in place until it is conveyed toward the powder outlet by a conveying component. In this example, the powder support may be a plate or panel positioned below the powder inlet.

[0017] Preferably, a gap exists between the powder inlet and the powder support. This gap defines the maximum height of powder that accumulates on the plate. Therefore, the gap is preferably larger than the rated particle size of the metering feeder. Preferably, the height of the plate and / or the height of the powder inlet is adjustable, thereby allowing adjustment of the gap height. For example, at least one of the powder support and the powder inlet can be releasably attached to a metering feeder support structure having a vertical extension and / or an adjustable vertical extension, thereby allowing adjustment of the gap.

[0018] The powder support can be inclined toward the powder outlet. However, preferably, the inclination is below a critical inclination, defined as the inclination where the static friction force and the downward inclination force have the same absolute value. Thus, increasing the inclination above the critical inclination will cause the powder to slide on the powder support. In other words, increasing the inclination of the powder support above the critical inclination will turn the powder support into a chute.

[0019] In another example, the powder support includes a grid, i.e., a sieve. We use the term "grid" only to distinguish it linguistically from another optional sieve explained below. Therefore, the term "first sieve" can be used instead of "grid" herein. The grid's mesh size is larger than the powder particles designated to be dispensed by the metering feeder. Preferably, the grid's mesh size is at least twice the size of the powder particles; particularly preferably, the grid's mesh size is at least three times the size of the powder particles. Further, the mesh size is smaller than a critical mesh size, defined as the mesh size beyond which powder will pass through the stationary grid and fall off.

[0020] In a preferred example, the powder support of the metering feeder is coupled to an ultrasonic transmitter and / or a vibration actuator (collectively referred to herein as "actuator"). The ultrasound and / or vibration reduce the critical tilt and angle of repose of the powder on the powder support, respectively. Thus, in the case that the powder support is a plate or slab, the powder slides toward the powder outlet. For the sake of clarity, "coupled" in this context describes a mechanical connection that allows the ultrasound generated by the ultrasonic transmitter to propagate within the powder support, such as in a grid. In the case of a vibration actuator, "coupled" describes a mechanical connection between the vibration actuator and the powder support (e.g., a grid) that transmits the vibration of the vibration actuator to the powder support. Vibration is considered to be movement of the grid, which can be "back-and-forth" movement or "up-and-down" movement, or a combination thereof. The vibration actuator can cause the powder support to oscillate itself, for example, between two positions and / or two orientations, but also (and / or) excite at least one conventional mode of the powder support. All these vibrations result in a reduction in the critical tilt angle and / or the critical angle of repose. A portion of the powder thus flows into the recoater container. When excited by ultrasound, the ultrasonic waves propagating through the powder support also reduce the critical tilt angle and critical repose angle. Furthermore, the ultrasound can propagate through the powder, thereby arguably "fluidizing" the bulk material and causing the powder to flow into the recoating container. Typically, in this text, the ultrasonic transmitter is an ultrasonic generator, also known as an ultrasonic transducer.

[0021] The fluidization can be progressively controlled by the energy generated by vibration and / or ultrasound excitation; that is, the volume of powder conveyed to the outlet per unit time can be adjusted by increasing or decreasing the excitation. For a given powder support with excitation, the conveying rate is constant; therefore, the amount of powder to be dispensed into the recoater container or into the recoater container can be adjusted by selecting the duration of excitation. In practice, the operation of the actuator is preferably controlled by a controller.

[0022] As noted above, the powder support preferably includes a grid, wherein the grid is coupled to an ultrasonic transmitter and / or a vibration driver, thereby being configured such that by operating the ultrasonic transmitter and / or the vibration driver, the powder can flow through the grid and exit the grid.

[0023] Preferably, the powder support includes a frame, wherein the grid is supported by the frame and preferably mechanically attached to the frame. This provides a stable grid and enables reliable connection of the ultrasonic transmitter and vibration actuator to the grid via the frame. The frame further simplifies the sealing of the powder support relative to the housing of the metering feeder.

[0024] The connecting elements can connect the grid via the frame, i.e., mechanically attach it to the ultrasonic transmitter and / or vibration driver.

[0025] For example, the metering feeder may include a feeder housing with a powder channel. The powder channel is defined by the channel wall of the housing. The powder channel may connect a powder inlet and a powder outlet. Preferably, a grid is positioned transversely to the longitudinal extension of the powder channel, thereby dividing the channel into an upper channel portion facing the inlet and a lower channel portion facing the outlet. In the case of a straight channel, the longitudinal extension of the powder channel can be considered to be defined by a longitudinal channel axis. In the case of a curved channel, it is assumed that the neutral axis of a curved beam located in the channel can be considered to define the direction of the longitudinal extension of any infinitesimal channel cross-section. Transverse means that the grid intersects the powder channel at an angle, preferably but not necessarily a right angle (±15°, preferably ±10°, even more preferably ±5° or less). The angle is preferably between 60° and 120°.

[0026] The housing can support the powder support. For example, the channel wall can form a recess into which the powder support is sealingly engaged. This allows for simple assembly while preventing bypass powder. Similarly, the powder support can include a recess into which a protrusion of the channel wall is sealingly engaged.

[0027] Particularly preferably, an elastic member is positioned between the powder support and the housing. This allows for sealing the gap between the powder support and the housing while preventing vibration from being directly transmitted from the powder support to the housing. Other components of the powder bed fusion apparatus are thus subjected to less ultrasonic and / or vibrational stress, thereby increasing their lifespan and operational accuracy. This, in turn, improves workpiece quality.

[0028] As is apparent, a metering feeder can be installed in a powder bed fusion apparatus, also known as a "powder fusion apparatus." The powder fusion apparatus may include at least a processing chamber and a powder hopper having a powder discharge opening, wherein the discharge opening is in fluid communication with the processing chamber. A recoater container can be positioned within the processing chamber. The powder inlet of the metering feeder is preferably located below the discharge opening of the powder hopper. Thus, once the powder inlet of the metering feeder is filled with powder, powder stops flowing out of the discharge opening. Powder delivered to the recoater container is replenished promptly by gravity. The powder outlet of the metering feeder is preferably located above the recoater's resting position. In this case, when the recoater is resting at its resting position, the powder outlet of the metering feeder can directly supply the recoater container. Typically, the recoater can be positioned at a resting location between coating cycles, the so-called resting position. Thus, between these coating cycles, the recoater container can be refilled from the powder outlet of the metering feeder.

[0029] Preferably, the powder silo has a powder inlet opening. Typically, the powder inlet opening can be connected to a powder dispensing system to transfer powder into the silo via the powder inlet opening. Powder can be supplied, for example, via a powder supply line from the main tank and / or an excess powder removal collector in the processing chamber. New powder is supplied to the silo from these powder sources via a powder conveying system. For example, a pneumatic conveying system can be used, wherein the conveying gas flow is preferably an inert gas flow. In a particularly preferred example, the powder inlet opening is protected by a sieve (different from the first sieve, i.e., a grid) to separate particles larger than a predetermined size. Thus, the (second) sieve has a (second) screen size for separating particles larger than the screen size. Therefore, these particles cannot be transported into the silo along with the powder.

[0030] As is already apparent, the bar screen has a mesh size, and preferably a mesh size larger than the sieve size, thereby preventing the accumulation of particles to be returned in the processing chamber. This measure ensures particularly high metering accuracy, primarily because the smooth area of ​​the bar screen does not decrease over time due to particle clogging. This improves the quality of the manufactured workpieces. The bar screen and sieve can be combined into a single bar screen. In particular, in this case, the metering feeder may include a bar screen residue removal slider. This bar screen residue removal slider can be configured to scrape residue from the bar screen into a residue container. For example, the bar screen residue removal slider can be movably supported by at least one guide rail and / or telescopic arm positioned upstream and / or beside the bar screen. Preferably, the bar screen residue removal slider is coupled to a drive for pushing the bar screen residue removal slider from a first position to a second position and for retracting the bar screen residue removal slider back to the first position above the upstream-facing bar screen surface.

[0031] A method for filling a container of a recoater in a powder fusion apparatus may at least include the step of discharging powder from a powder hopper onto a powder support of a metering feeder, for example, discharging onto a powder support of a metering feeder as explained above. Further, the method may include exciting phonons in the powder support of the metering feeder, and / or exciting the powder support to oscillate relative to the processing chamber boundary and to excite the powder support in a conventional mode. Each of these measures enables the powder to be conveyed to the recoater container in a controlled manner via the outlet of the metering feeder. Attached Figure Description

[0032] In the following description, without limiting the general inventive concept, the invention will be illustrated by way of example embodiments with reference to the accompanying drawings:

[0033] Figure 1 A first example of a powder bed fusion apparatus is shown.

[0034] Figure 2 A second example of a powder bed fusion apparatus is shown.

[0035] Figure 3 An example of a metering feeder is shown in a longitudinal sectional view.

[0036] Figure 4 Perpendicular to Figure 3 The cross section view in the view shows Figure 4 Metering supply device.

[0037] Figure 1The powder bed fusion apparatus 1 has a processing chamber 10 defined by a processing chamber housing wall 12. In operation, the processing chamber 10 is preferably filled with an inert gas. In a preferred example, the inert gas flows into the processing chamber 10 through at least a first opening in the processing chamber housing wall 12 and exits the processing chamber 10 through at least one other opening.

[0038] The processing chamber 10 has a base plate 11, which is considered the bottom 11 of the processing chamber 10. A support opening 14 accommodates a movably supported workpiece support 13, which supports a workpiece 4. To manufacture the workpiece 4, powder 9 on top of the workpiece support 4 in the powder bed 6 is fused by a beam generated by a beam ejection unit 3. The beam ejection unit 3 may include a beam deflector configured to deflect the generated beam onto the powder bed 6.

[0039] In order to continuously fuse the powder 9 layer 7, a recoating device 61 is used in each fusion step.

[0040] (or 62, see also) Figure 2 A new layer 7 of powder 9 can be added on top of the powder bed 6. Thereafter, by selectively heating the powder particles using the beam generating unit 3, a portion of the powder particles in the newly applied top layer 7 is attached to the workpiece 4 covered by the top layer 7. After the particles of the top layer 7 have been attached to and thus bonded to the workpiece 4, the workpiece support 13 is lowered, and the recoater 61 travels above the support opening 14, thereby applying the new layer 7 of powder 9.

[0041] As in Figure 1 As described herein, the recoater 61 may have a recoater container 65. Each time the recoater 61 applies a new layer 7 of powder to the powder bed, the powder level in the recoater container decreases because at least a portion of the powder 9 stored in the recoater container 65 is added to the powder bed 6 by the recoater 61. Once the powder level in the recoater container 65 falls below a given level and / or after each recoating step, the recoater container 65 may be (re)filled. For this purpose, the recoater container 65 may be positioned below the discharge opening 22 of an intermediate container 20, which herein is referred to as the powder hopper 20 or simply the hopper 20, as explained above.

[0042] A metering feeder 40 can be positioned between the discharge opening 22 of the hopper 20 and the recoater container 65. Therefore, the metering feeder 40 can control the amount of powder transferred from the hopper 20 to the recoater container 65. The metering feeder 40 can be connected to the controller 100 of the powder bed fusion apparatus via at least one control line 101. Therefore, the controller can be configured to control the amount of powder delivered to the recoater container 65 via the metering feeder 40. In the depicted example, the driver 57 of the metering feeder 40 is connected to the controller 100 via at least one control line 101.

[0043] Preferably, the powder bed fusion apparatus further includes at least one main powder tank 8 or is connected to at least one main powder tank 8, which is connected via a powder pipeline of the powder dispensing system 6 to the powder inlet 21 of one or more silos 20, as shown in... Figure 1 and Figure 2 As shown in the diagram. (Second) The sieve can be positioned upstream of the powder inlet 21 of the hopper.

[0044] The main powder tank 8 can be securely connected to or separate from the housing, which encloses the processing chamber 10, the hopper 20, and the beam generation unit 3. Furthermore, different hoppers 20, each enclosed by a different housing, can be jointly connected to at least one main powder tank 8. Typically, at least one main powder tank 8 can be connected to multiple different powder bed fusion devices and configured to supply the respective hoppers of these devices via powder supply lines.

[0045] exist Figure 1 and Figure 2 In the text, the main tank 8 is described as being smaller than the silo 20; however, in practice, it is preferred that the main tank 8 be no smaller than the silo 20.

[0046] Excess powder can be collected in an optional excess powder collector 15 in the bottom plate 11 and can be conveyed to the hopper 20 via an optional (sieve) upstream of the powder inlet 21 through the powder dispensing system 6.

[0047] It should be noted that, Figure 1 Two hoppers and two metering feeders are shown. In other examples, only a single hopper 20 and a single metering feeder 40 may be used. In this sense, a powder bed fusion apparatus may include at least one hopper 20. In still other examples, the hopper 20 may be omitted. In these examples, the metering feeder may receive powder to be directly dispensed from tank 8, for example, via an optional (second) sieve upstream of the metering feeder. For example, a powder bed fusion apparatus may include multiple hoppers 20 and / or multiple metering feeders 40, wherein different hoppers 20 and / or different metering feeders 40 may be configured to supply different powders (the particle size and / or material composition of the powder may differ) to the recoater.

[0048] Figure 2 Another powder bed fusion apparatus 1 is shown, which is related to... Figure 1 The powder bed fusion equipment 1 is very similar to that in the previous one, except for the recoating unit. Figure 1 The description can also be found in Figure 2 Interpretation in Chinese. Figure 2 In the middle, the recoating device 62 does not have such Figure 1 The movable container of the recoating device 61. Figure 2 The recoater 62 has a dispensing device, such as a scraper, which is movably supported to move back and forth above the support opening 14, thereby dispensing a certain amount of powder 9, which is deposited on the top of the base plate 11 of the processing chamber 10, which defines the bottom of the processing chamber 10. The location where the powder dam has been deposited is thus the powder container 65. This powder dam can be pushed by the recoater 62 above the support opening 14, thereby applying a new layer of powder 7 to the powder bed 6. In this sense, the location on the base plate 11 supporting the powder dam of 9 can be considered the recoater container 65. As per [reference to...] Figure 1 As explained, the metering feeder can be positioned below the discharge opening 22 of the hopper 20. Thus, the powder 9 in the hopper 20 flows onto the powder support plate 55 until a dam of powder 9 accumulates on the support plate 55, blocking the discharge opening 22. Therefore, the discharge opening 22 can be considered to define the powder inlet 51 of the metering feeder 40.

[0049] As in Figure 2 As depicted, the powder support plate 55 can be connected to a driver 57 (shown as 57a and 57b). The driver 57 is preferably an ultrasonic transmitter coupled to at least one support plate 55, thereby transmitting ultrasonic waves to the powder support plate 55. Alternatively, the driver can cause the powder support plate to reciprocate or excite other types of vibrations in the powder support plate 55. The ultrasound and / or vibration at least partially fluidize the powder dam on the powder support plate, and thereby allow the powder to flow across the edge 551 of the powder support plate 55 facing the processing chamber 10 to a position 65 (recoater container 65) on the base plate 11. The edge 551 can thus be considered as... Figure 2 The powder outlet of the metering feeder 40 in the middle.

[0050] The amount of powder 9 dispensed to position 65 can be controlled by controller 100, for example, by controlling the operating time of the corresponding driver 57, assuming the amplitude and frequency of the excitation are constant. However, the controller can also control the frequency and / or amplitude of the excitation.

[0051] exist Figure 3 and Figure 4Another preferred example of a metering feeder is depicted: metering feeder 40 can replace... Figure 1 Neutralize / or Figure 2 Metering supply device 40 in the middle.

[0052] As in Figure 3 and Figure 4 As shown, the metering feeder 40 may have a housing 50 having a channel 52 defined by a channel wall 521. The channel wall 521 has at least a first opening 51 and a second opening 53, namely a powder inlet 51 and a powder outlet 53. In other words, (if the channel is not filled with powder) the channel 52 can provide fluid communication from the powder inlet to the powder outlet.

[0053] Channel 52 may have a recess 522, and the frame 54 of the powder support may engage in the recess 544, thereby holding the powder support in a position where it crosses channel 52. The powder support thus divides channel 52 into an upper portion and a lower portion, wherein (if installed as intended) the powder inlet faces upward toward the discharge opening of hopper 20, and the powder outlet 53 faces downward toward the container. In a preferred embodiment, the powder inlet is attached to the powder discharge opening 22 (see...). Figure 1 ).

[0054] The frame 54 is preferably peripherally engaged in the recess 522, and the gap between the frame 54 and the channel wall 521 is preferably sealed, for example by at least one gasket 523. The frame 54 may support a powder support grid 55, which is a sieve. The sieve mesh size is preferably larger than a specified median particle size of the powder 9, but smaller than a critical mesh size. Thus, as long as the powder support grid 55 is not activated by the actuator 57, the powder 9 falling down through the discharge opening 22 of the hopper into the channel 52 accumulates on the grid, while only negligible amounts of powder fall through the grid, the actuator 57 being an ultrasonic transmitter and / or a vibration actuator. However, operating the actuator 57 releases the powder to flow through the grid 55 and the lower portion of the channel 52 into (or onto) the recoater container 65. Similar to... Figure 1 and Figure 2 In the example, driver 57 can be controlled by controller 100 via control line 101.

[0055] List of reference numerals

[0056] 1. Powder bed fusion equipment

[0057] 3-beam emission unit

[0058] 4. Workpiece

[0059] 6 Powder Bed

[0060] 7 Powder Layer

[0061] 8 Main Powder Tank

[0062] 9 Powder

[0063] 10 Processing Chamber

[0064] 11 Base plate / bottom

[0065] 12 Processing chamber shell wall

[0066] 13 Workpiece support components

[0067] 14. Support opening

[0068] 15 Excess Powder Collector

[0069] 16 Powder Conveying System

[0070] 20. Silos / Intermediate Containers

[0071] 21 Powder inlet of the silo

[0072] 22 Discharge opening of the silo

[0073] 40 Metering feeder

[0074] 50 Metering feeder housing

[0075] 51 Powder inlet of metering feeder

[0076] 52. Metering feeder channel

[0077] 521 Channel Wall

[0078] 522 Recesses in the channel wall

[0079] 523 Washer

[0080] 53 Powder outlet of metering feeder

[0081] 54 Frames

[0082] 55 Powder Support Grating / Powder Support Plate

[0083] 551 Edge of powder support plate 55

[0084] 56 Connecting elements

[0085] 57a, 57b Vibration Driver / Ultrasonic Transmitter

[0086] 61 ((i) type) recoating device

[0087] 62 ((ii) type) recoating device

[0088] 65 Recoating container

[0089] 100 Control Unit

[0090] 101 Control Line

Claims

1. A dosing feeder (40) for a powder bed fusion apparatus (1), wherein, The metering supply device (40) includes: - Powder inlet (51), which is configured to receive powder (9) from the discharge opening (22) of the powder hopper (20). - Powder outlet (53), which is configured to release powder (9) into the recoater container (65) of the powder bed fusion apparatus (1). - Powder support (55), which is located between the powder inlet (51) and the powder outlet (53) and is configured to convey powder (9) from the powder inlet (51) to the powder outlet (53). Its features are, The recoating container (65) is an apparatus of the recoating device (61), and the powder outlet (53) is configured to directly supply powder to the recoating container (65) when the recoating device (61) is in the parking position, or the recoating container (65) is located on the base plate (11) of the processing chamber (10), and the powder is dispensed from the base plate (11) via the recoating device (61). The powder support (55) is coupled to an ultrasonic transmitter (57) and / or a vibration driver (57), and the powder support (55) includes a grid, and the grid is coupled to the ultrasonic transmitter (57) and / or the vibration driver (57), thereby being configured such that by operating the ultrasonic transmitter (57) and / or the vibration driver (57), powder can flow through the grid and exit the grid.

2. Dosing feeder (40) according to claim 1, characterized in that The powder support (55) includes a frame (54), wherein the grid is supported by the frame (54).

3. A dosing feeder (40) according to claim 2, characterized in that The connecting element (56) connects the grid to the ultrasonic transmitter (57) and / or the vibration driver (57) via the frame (54).

4. The metering feeder (40) according to any one of claims 1 to 3, characterized in that, - The metering feeder (40) includes a feeder housing (50) having a powder channel (52) having a channel wall (521), wherein the powder channel (52) connects the powder inlet (51) and the powder outlet (53). - The grid is positioned transversely to the longitudinal extension of the powder channel (52), thereby dividing the powder channel (52) into an upper channel portion facing the inlet and a lower channel portion facing the outlet.

5. Dosing feeder (40) according to claim 4, characterized in that The channel wall (521) forms a recess, and the powder support is sealed into the recess.

6. A dosing feeder (40) according to claim 4 or 5, characterized in that The powder support (55) has a recess, and the protrusion of the channel wall (521) is sealed into the recess.

7. A dosing feeder (40) according to one of claims 4 to 6, characterized in that An elastic member (523) is positioned between the powder support (55) and the housing (50) to prevent vibration from being directly transmitted from the powder support (55) to the housing (50).

8. The metering feeder of claim 1, wherein, The grid has a mesh size, wherein the mesh size of the grid is larger than the powder particles to be dispensed through the metering feeder.

9. The metering feeder according to claim 8, characterized in that, The mesh size of the grid is at least twice the size of the powder particles, or the mesh size of the grid is at least three times the size of the powder particles.

10. The metering feeder according to claim 8 or 9, characterized in that, The mesh size of the grid is smaller than the critical mesh size, which is defined as: if the mesh size exceeds the critical mesh size, the powder will fall through the stationary grid.

11. A powder bed fusion apparatus (1), the powder bed fusion apparatus (1) comprising: - Processing chamber (10). - A powder hopper (20) having a discharge opening (22) wherein the discharge opening (22) connects the volume of the powder hopper to the processing chamber (10). - Recoating container (65), the recoating container (65) being in the processing chamber (10), and - At least one metering feeder (40). The feature is that the at least one metering feeder (40) is a metering feeder (40) according to any one of claims 1 to 10, the powder inlet (51) of the metering feeder is located below the discharge opening (22) of the powder hopper (20), and the powder outlet (53) of the metering feeder is located above the recoating container (65).

12. The powder bed fusion apparatus (1) according to claim 11, characterized in that, The powder hopper (20) has a powder inlet opening (21) connected to a powder dispensing system (6) so that powder (9) can be conveyed into the hopper (20) via the powder inlet opening (21) of the hopper, and the powder inlet opening (21) is protected by a sieve (5) so as to separate particles larger than a predetermined size, the sieve (5) having a screen size.

13. The powder bed fusion apparatus (1) according to claim 12, characterized in that, The grid has a grid mesh size, and the grid mesh size is larger than the screen size.

14. A method for filling a recoating container (65) of a powder bed fusion apparatus (1), wherein, The powder bed fusion apparatus (1) includes a processing chamber (10), a powder hopper (20), a recoater container (65), and a metering feeder (40). The powder hopper (20) has a discharge opening (22), wherein the discharge opening (22) connects the volume of the powder hopper to the processing chamber (10). The recoater container (65) is located in the processing chamber (10). The powder inlet (51) of the metering feeder is positioned below the discharge opening (22) of the powder hopper (20), and the powder outlet (53) of the metering feeder is positioned above the recoater container (65). The metering feeder (40) has a powder support (55). The method includes the following steps: (i) Discharge powder (9) from the powder hopper (20) onto or into the grid of the powder support (55), (ii) Ultrasonic waves are excited in the grid of the powder support (55) of the metering supply (40), and / or the grid of the powder support (55) is excited to vibrate relative to the wall (12) of the processing chamber, thereby conveying powder (9) to the recoater container (65) via the powder outlet (53) of the metering supply (40), wherein the recoater container (65) is an instrument of the recoater (61), and the powder outlet (53) is configured to directly supply the recoater container (65) when the recoater (61) is in the parking position, or the recoater container (65) is located on the base plate of the processing chamber and the powder is dispensed from the base plate by the recoater (61).

15. The method according to claim 14, characterized in that, The activated powder support (55) is the powder support (55) of the metering feeder (40) according to any one of claims 1 to 10, and / or the activated powder support (55) is the powder support (55) of the powder bed fusion apparatus (1) according to any one of claims 11 to 13.

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