System and method for distributing raw material powder to multiple additive manufacturing devices

Abstract

The present disclosure relates to a system (5) for distributing raw material powder (6) from a reservoir (7) of raw material powder to a plurality of at least two additive manufacturing devices (3) for additive manufacturing, the system (5) comprising at least one gas flow driver (11) and at least two conveying lines (15) for conveying the raw material powder (6) to the at least two additive manufacturing devices (3) by a gas flow driven by the at least one gas flow driver (11), and characterized in that: The system further includes a supply manifold (30) for supplying raw material powder (6) to the at least two conveying lines (15), the supply manifold (30) constructed and arranged to be controlled by at least two shut-off valves (37) to selectively direct the raw material powder (6) to one of the at least two conveying lines (15), each of the at least two shut-off valves (37) being disposed in the supply manifold (30) and configured to selectively open and close to selectively supply the raw material powder (6) to the at least two conveying lines (15).

Description

[Technical Field]

[0001] The present disclosure relates to a system and method for distributing raw material powder from a reservoir of raw material powder to a plurality of at least two additive manufacturing devices. In particular, the present disclosure relates to an additive manufacturing facility for continuous production on an industrial scale, the additive manufacturing facility comprising a plurality of additive manufacturing devices for parallel additive manufacturing of three-dimensional workpieces. More particularly, the additive manufacturing devices are preferably configured to apply laser powder bed fusion (LPBF) as an additive manufacturing technique for manufacturing metal workpieces. [Background technology]

[0002] The additive manufacturing of three-dimensional workpieces is often referred to as 3D printing. A specific form of additive manufacturing is laser powder bed fusion (LPBF), in which layers of raw material powder are exposed to a high-energy beam of electromagnetic radiation, such as a laser beam or particle beam, to selectively sinter and / or melt the particles of the raw material powder. The three-dimensional workpiece is produced by sequentially sintering and / or melting each layer of raw material powder.

[0003] Compared to traditional manufacturing techniques like molding, additive manufacturing of a single three-dimensional workpiece is significantly more time-consuming. Therefore, in the early days of 3D printing, additive manufacturing was only applied to prototyping or a small number of individual parts. However, because additive manufacturing offers the possibility of designing and manufacturing components unavailable through other traditional manufacturing techniques, there is a demand for its use in industrial-scale serial production. Developments in additive manufacturing over the past few decades have led to some reductions in production time per layer, for example, by using multiple lasers in parallel. However, there is a limit to how much production time can be reduced per layer. Therefore, to use additive manufacturing for industrial-scale serial production, several components must be manufactured in parallel. For example, several hundred or even thousands of small components can be densely packed to form a three-dimensional workpiece that maximizes the use of available production volume. However, there is also a limit to the maximum amount of available production volume. To further utilize additive manufacturing for parallel processing, an additive manufacturing facility may include multiple additive manufacturing machines or process chambers. In principle, there is no limit to the number of additive manufacturing machines that can be operated in parallel.

[0004] Because each additive manufacturing process may require a supply of raw material powder, it is inefficient to provide the necessary infrastructure for supplying raw material powder separately for each additive manufacturing device. It is more efficient to provide a common infrastructure for supplying raw material powder to multiple additive manufacturing devices. For example, U.S. Patent Application Publication No. 2018 / 0021855 (A1) discloses a method for managing powder supply in an additive manufacturing facility with multiple devices. U.S. Patent No. 7,296,599 (B2) (A1) describes a method and apparatus for pneumatically transferring powder from a powder supply container to a single laser sintering system, where the powder supply container is pressurized to force the powder into a supply line. DE 20 2019 106 061 U1 describes another powder transport system for a single additive manufacturing device.

[0005] The challenge with known powder delivery systems is to reliably and consistently distribute a defined flow rate of raw powder to an additive manufacturing machine while reducing the risk of clogging or valve wear due to the abrasive nature of the raw powder. Summary of the Invention

[0006] It is therefore an object of the present disclosure to provide a system and method for more consistently distributing a defined flow rate of raw material powder from a reservoir of raw material powder to a plurality of at least two additive manufacturing devices for additive manufacturing with reduced risk of clogging and valve wear.

[0007] The solution to this problem is given by the subject matter of the independent claims. Preferred embodiments can be inferred from the dependent claims, the description and the figures.

[0008] According to a first aspect of the present disclosure, there is provided a system for distributing raw material powder from a raw material powder reservoir to a plurality of at least two additive manufacturing machines for additive manufacturing. The system includes at least one gas flow drive and at least two transfer lines for transporting the raw material powder to the at least two additive manufacturing machines by a gas flow driven by the at least one gas flow drive. The system further includes a feeding manifold for supplying the raw material powder to the at least two transfer lines. The feeding manifold is controlled by at least two shut-off valves and is constructed and arranged to selectively direct the raw material powder to one of the at least two transfer lines. Each of the at least two shut-off valves is disposed on the feeding manifold and configured to selectively open and close to selectively supply the raw material powder to the at least two transfer lines.

[0009] This means that the supply manifold is not part of the transfer line, which allows the feedstock powder to be transported by gas flow through the transfer line without branches or valves on its way to the additive manufacturing device, i.e. downstream of the supply manifold and upstream of the additive manufacturing device.

[0010] Optionally, the supply manifold may comprise a manifold inlet for receiving the feedstock powder from the reservoir, a pipe branch branching into at least two manifold branches, and at least two manifold outlets each connecting to one of the at least two conveying lines, wherein each of the at least two manifold branches connects the manifold inlet to one of the at least two manifold outlets, and each of the at least two shut-off valves is associated with and arranged at one of the at least two manifold branches and configured to selectively open and close the associated manifold branch.

[0011] If necessary, the pipe branch may be configured to be located at a higher altitude than the at least two manifold outlets, so that the raw material powder is transported through the at least two manifold branches primarily by gravity. Therefore, the raw material powder preferably falls and / or slides through the supply manifold into the gas flow of the conveying line. Furthermore, the gas flow in any of the conveying lines may provide a Venturi effect to suck the raw material powder from the connected manifold outlet. To enhance the Venturi effect, the cross section of the conveying line may be somewhat smaller at the connected manifold outlet. Alternatively, or in addition, the gas flow driven (sent) by the at least one gas flow driver may be partially or completely directed through the manifold branches to transport the raw material powder through the supply manifold.

[0012] If necessary, the supply manifold may be configured to be positioned above a portion of each of the at least two conveying lines, with each manifold outlet communicating substantially from above with one of the at least two conveying lines. This allows the raw material powder to fall along the conveying line into the gas flow. Each of the at least two conveying lines preferably extends substantially horizontally below the supply manifold. Preferably, at least a portion of the manifold branch extends substantially vertically.

[0013] Optionally, the supply manifold is configured to discharge the raw material powder into at least two conveying lines with (including) a momentum component parallel to the conveying direction along the conveying line. The conveying direction here is the direction of the gas flow. Therefore, the manifold branches may be bent and / or tilted at the bottom of the manifold outlet so that the average momentum vector of the raw material powder is preferably not perpendicular to the gas flow direction, but already includes a momentum component parallel to the gas flow before entering the gas flow. This has the additional advantage of reducing the possibility that the gas flow will enter the manifold branches at the manifold outlet and push the raw material powder back upward.

[0014] Optionally, the supply manifold may have n≧2 manifold branches, where n∈N, where the manifold branches connect to the manifold inlets with pipes that branch in n-fold rotational symmetry about the central vertical axis of the manifold inlet. This is a preferred design that is very compact and facilitates even distribution of feedstock powder to the manifold branches. The manifold branches may extend laterally and downward from the pipe branches like spider legs.

[0015] Optionally, the supply manifold may have at least two manifold branches, each of which preferably has a slope inclined at an angle of 20 to 70 degrees relative to the central vertical axis of the manifold inlet. Therefore, the raw material powder can slide along the slope driven by gravity. A shutoff valve may preferably be disposed on the slope.

[0016] If necessary, the supply manifold may have at least two manifold branches with the same pipe length leading from the pipe branch to at least two conveying lines, which is beneficial for evenly distributing the raw material powder to the manifold branches.

[0017] If desired, each section of the at least two transfer lines can be arranged in parallel below the supply manifold, which is advantageous for a compact and neat system design.

[0018] Optionally, each of the at least two shut-off valves may be a butterfly valve. Alternatively, or in addition, one or more of the at least two shut-off valves may be another type of valve, such as a solenoid valve, a ball valve, a gate valve, a piston valve, a needle valve, a pinch valve, or another type of valve. Each of the at least two shut-off valves may include a valve motor for actuating the valve body.

[0019] Optionally, each of the at least two shut-off valves may be disposed in an inclined portion of one of the at least two manifold branches of the supply manifold, and may include a valve body operable about an actuator axis substantially perpendicular to the longitudinal axis of the inclined portion of the manifold branch. Here, the actuator axis and the longitudinal axis of the inclined portion of the manifold branch span an imaginary plane inclined with respect to an imaginary vertical plane. This is advantageous for compactly arranging the shut-off valves. Optionally, the actuator axis may also be inclined with respect to an imaginary horizontal plane. This is due to the fact that the raw material powder preferably slides along the inclined portion of the manifold branch.

[0020] Optionally, the system may further include a dosing unit, which includes a conveying mechanism for conveying a controlled flow of raw material powder from the reservoir outlet to the manifold inlet. Preferably, the dosing unit may include a screw conveyor, which is configured and arranged to convey the raw material powder from a first location at the reservoir outlet to a second location at the manifold inlet, and wherein the second location is at a higher elevation than the first location and / or the second location is horizontally spaced apart from the first location. Alternatively or additionally, the dosing unit may include another type of conveyor, such as a belt conveyor or a vibrating chute.

[0021] If necessary, the at least two shut-off valves may be configured to open only one of the at least two shut-off valves at a time. This facilitates control of a stable and constant gas flow, making the flow of raw material powder more stable. In the event of competing demands among different additive manufacturing devices, the resource management system may manage the sequential distribution of raw material powder to only one additive manufacturing device at a time.

[0022] If necessary, the at least two shutoff valves may be positioned closer to the pipe branch of the supply manifold than the at least two conveying lines. The longer the distance from the valves to the pipe branch, the more raw material powder will accumulate at the pipe branch when the shutoff valves are closed. To minimize the amount of raw material powder that accumulates at the manifold branch, the distance from the valves to the pipe branch is preferably selected to be as short as possible, preferably less than 2 m, more preferably less than 1 m, and most preferably less than 50 cm.

[0023] Optionally, the distance to the pipe branch of the supply manifold may be the same for all of the at least two shutoff valves. This is beneficial for ensuring that the amount of raw material powder accumulated in the manifold branch when the shutoff valve is closed is substantially the same for all of the manifold branches. Optionally, the distance may define a manifold volume for accommodating a specified amount of raw material powder that is retained on the valve body of each of the at least two shutoff valves when closed.

[0024] Optionally, the system may further comprise a vibration unit for shaking and / or vibrating the feed manifold, for example by ultrasonic and / or pneumatic and / or electrical vibrations, to promote the descent of the raw material powder through the feed manifold, which is advantageous in preventing clogging, agglomeration and / or accumulation of residual raw material powder in the feed manifold.

[0025] If desired, the system may include alternative or additional means for facilitating the fall of the feed powder through the feed manifold, such as one or more nozzles for blowing gas into the powder accumulated in the feed manifold, and / or one or more agitators.

[0026] Optionally, the supply manifold may comprise at least one vibration damping element for damping the propagation of vibrations from the supply manifold to the at least two conveying lines and / or towards the reservoir. Preferably, the at least one vibration damping element "decouples" the supply manifold from other parts of the system connected to it in terms of the propagation of vibrations generated by the vibrating unit, preventing or at least reducing the propagation of those vibrations to other parts of the system.

[0027] Optionally, the at least two transfer lines downstream of the supply manifold and upstream of the at least two additive manufacturing devices may not have gas flow valves, which is highly beneficial because the at least two transfer lines carry the majority of the feedstock powder along this path and wear on the gas flow valves on this path is high due to the abrasive nature of the feedstock powder.

[0028] Optionally, the at least two conveying lines may be part of a gas flow circulation loop, wherein the gas flow driver is configured to drive a gas flow circulating within the gas flow circulation loop. Preferably, the at least two conveying lines are parallel lines of the gas flow circulation loop connected to the gas flow driver.

[0029] Optionally, the system may further include at least two gas flow regulator valves, each associated with one of the at least two transport lines and configured to selectively regulate the gas flow in the associated transport line. Also herein, the at least two gas flow regulator valves are disposed downstream of the at least two additive manufacturing devices and upstream of the supply manifold. Therefore, preferably, the at least two gas flow regulator valves are disposed in parallel gas return lines that return the gas flow toward the gas flow driver. Preferably, there may be one parallel gas return line equipped with a gas flow regulator valve for each transport line. In the additive manufacturing device, the raw powder is preferably separated from the gas flow by a separator, such as a cyclone separator or a vacuum conveyor, for filling the raw powder buffer of the additive manufacturing device. Therefore, the amount of raw powder is significantly reduced in the gas return line that directs the gas flow back toward the gas flow driver. Therefore, the gas flow regulator valve in the gas return line is less exposed to abrasive wear from the raw powder. An additional particle filter may be placed upstream of the pump and / or at the inlet to the pump.

[0030] Downstream of the at least two gas flow regulating valves, the parallel gas return lines may merge with a pump inlet line connected to the suction side of a gas pump that functions as a gas flow driver. The pressure side of the gas pump may be connected to the parallel conveying line via the pump outlet line, thereby closing the gas flow circulation loop. To protect the gas pump from residual amounts of raw material powder in the return gas flow, a vacuum conveyor or another separator device may be disposed in the pump inlet line to separate the residual amounts of raw material powder from the return gas flow. Such residual amounts of raw material powder may be sieved and recycled to replenish the raw material powder reservoir. The raw material powder reservoir may be additionally replenished with unused raw material powder and / or recycled raw material powder that was not sintered or melted in the additive manufacturing apparatus.

[0031] According to a second aspect of the present disclosure, there is provided an additive manufacturing facility comprising: That is, a plurality of at least two additive manufacturing devices for parallel additive manufacturing of three-dimensional workpieces; a system as described above for distributing raw material powder from a reservoir of raw material powder to at least two additive manufacturing devices;

[0032] Optionally, the additive manufacturing equipment further comprises a gas flow circulation loop with a gas flow driver, wherein the gas flow driver is configured to drive a gas flow circulating within the gas flow circulation loop, and wherein the at least two conveying lines of the system are parallel lines of the gas flow circulation loop.

[0033] According to a third aspect of the present disclosure, there is provided a method for distributing raw material powder from a reservoir of raw material powder to a plurality of at least two additive manufacturing devices for parallel additive manufacturing of three-dimensional workpieces, the method including: Gas flow in at least two of the delivery lines is selectively adjusted. Here, each of the at least two transport lines is associated with one of the at least two additive manufacturing devices, and the raw material powder is transported to the associated additive manufacturing device by a gas flow. At least two isolation valves in the supply manifold are selectively opened and closed. Here, each shut-off valve is associated with one of at least two conveying lines to selectively drop raw material powder into the gas stream of the associated conveying line.

[0034] The method may be implemented in the form of hardware as a control device as part of the system or facility described above, and / or in the form of a software program executable on a computer device as part of the system or facility described above.

[0035] If desired, the gas flow may be selectively adjusted before any one of the at least two shutoff valves is opened. This may result in raw material powder entering the transfer line without a gas flow, which could lead to raw material powder accumulating and filling the transfer line. Instead, it is desirable to drop the raw material powder into the existing gas flow, which is being immediately transferred, to ensure that the raw material powder does not become trapped in the transfer line.

[0036] Optionally, the gas flow may be selectively regulated by at least two gas flow regulator valves, each associated with one of the at least two transfer lines and configured to selectively regulate the gas flow in the associated transfer line, and wherein the at least two gas flow regulator valves are disposed downstream of the at least two additive manufacturing devices and upstream of the supply manifold. A control device and / or a programmed computing device may be in wireless or wired signal communication with each of the at least two gas flow regulator valves and individually control them.

[0037] If desired, the gas flow may be selectively adjusted to flow through only one of the at least two delivery lines at a time, so that the gas flow driven by the gas flow driver does not need to match the parallel gas flows in the delivery lines, facilitating a stable and even distribution of the defined gas flow through the delivery lines.

[0038] If necessary, only one of the at least two shutoff valves is opened at a time. Preferably, these are the two shutoff valves associated with the delivery line currently carrying the gas flow. A control device and / or a programmed computer device may be wirelessly or wired connected to each of the at least two shutoff valves and control them individually. Preferably, the control device and / or the programmed computer device is the same as the one signal-connected to the gas flow regulating valve. The same control device and / or the programmed computer device may be used to control the dosing unit and / or the vibration unit.

[0039] Different types of sensors can be used in the system to control gas flow and / or other system parameters, such as oxygen sensors, pressure sensors, flow sensors, or any other suitable sensors. The sensors may be connected to a controller. Pressure sensors can be used to detect blockages and leaks. Flow sensors, particularly those located downstream of the pump, can be used to adjust the pump output in relation to the amount and type of powder being delivered. Control variables can be pump speed, pump flow rate, dosing capacity, and / or pressure differential across the pump.

[0040] In a preferred embodiment, each transfer line may be equipped with at least one of an oxygen sensor, a pressure sensor, or a flow sensor, and in particular, each transfer line may be equipped with at least a pressure sensor and / or a flow sensor. This arrangement may facilitate detection of system anomalies. For example, a controller may monitor sensor values and compare them with expected values and / or threshold values. The controller may, for example, verify whether gas flow is measured in a transfer line before opening an associated shutoff valve to supply raw material powder to the transfer line. The controller may notify an operator of the anomaly and / or inhibit system operation.

[0041] Further embodiments of the present disclosure will now be described, by way of example only, with reference to the following figures: [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of an additive manufacturing facility according to the present disclosure. [Figure 2] FIG. 1 is a perspective view illustrating an example of a system for dispensing raw material powder according to the present disclosure. [Figure 3] FIG. 3 is a top view of the system shown in FIG. 2. [Figure 4] FIG. 4 is a cutaway view of the system shown in FIG. 3 along plane AA. [Figure 5a] FIG. 4 is a cutaway view of the system shown in FIG. 3 along plane BB. [Figure 5b] FIG. 4 is a cutaway view of the system shown in FIG. 3 along plane BB. DETAILED DESCRIPTION OF THE INVENTION

[0043] FIG. 1 shows an additive manufacturing installation 1 including six additive manufacturing devices 3 for the parallel additive manufacturing of three-dimensional workpieces. The additive manufacturing installation 1 further includes a system 5 for distributing raw material powder 6 from a reservoir 7 to the additive manufacturing devices 3. The additive manufacturing installation 1 further includes a gas flow circulation loop 9 for pneumatically transporting the raw material powder 6 to the additive manufacturing devices 3. The gas flow in the gas flow circulation loop 9 is driven by a gas flow driver 11 in the form of a gas pump. A pump outlet line 13 of the gas flow circulation loop 9 is connected to a pressure outlet of the gas pump 11 and splits into six parallel transfer lines 15. Each of the transfer lines 15 leads to a separator 17 associated with each of the additive manufacturing devices 3. The separator 17 may be a cyclone separator for extracting the raw material powder 6 from the gas flow and loading it into a raw material buffer of the associated additive manufacturing device 3.

[0044] Downstream of the separators 17, gas return lines 19 (i.e., six parallel gas return lines 19 for each of the six separators 17) return the gas flow toward gas flow control valves 21, each of which is located at the end of one of the gas return lines 19. Downstream of the gas flow control valves 21, the gas flow merges with pump inlet lines 23. Before the pump inlet lines 23 direct the gas flow to the suction port of the gas pump 11, a vacuum conveyor 25 is located in the pump inlet lines 23 to separate any residual raw material powder in the gas flow. The residual raw material powder thus separated is sieved using a sieve 27 and recycled to recharge the reservoir 7.

[0045] The reservoir 7 is a hopper-like container. The reservoir 7 is filled via a sieve 27 and / or can receive new raw material powder from a virgin raw material powder supply 29 and / or from a raw material powder recycling system 31. The raw material powder recycling system 31 can receive raw material powder that was not sintered or melted during the additive manufacturing process in the additive manufacturing apparatus 3 and recycle it for reuse (indicated by a double dashed line in FIG. 1 ).

[0046] The system 5 for distributing the raw material powder 6 to the six conveying lines 15 comprises a dosing unit 27 and a supply manifold 30. The dosing unit 27, here a screw conveyor positioned below the reservoir 7, receives the raw material powder 6 dropping from the bottom outlet of the reservoir 7 and conveys the raw material powder 6 upward and sideways at a set speed toward a manifold inlet 32 of the supply manifold 30. Below the manifold inlet 32, the supply manifold 30 comprises a pipe branch 33 that splits into six manifold branches 35. Each of the manifold branches 35 comprises a shut-off valve 37 for selectively allowing the raw material powder to drop and / or slide through the manifold branch 35 into the gas flow of the conveying lines 15 further below. At the bottom of the supply manifold 30, each manifold branch 35 comprises a manifold outlet 38 to one of the conveying lines 15. The feed powder primarily falls substantially by gravity through the feed manifold 30 from a manifold inlet 32 at the top of the feed manifold 30 to a manifold outlet 37 at the bottom of the feed manifold 30 .

[0047] The system 5 further comprises a vibration unit 39 for shaking and / or vibrating the feed manifold 30 to promote the fall of the raw material powder through the feed manifold 30 .

[0048] The system 5 further includes a control unit 41, which may be a hard-wired and / or software-programmed control device, in signal communication (shown by dashed lines in FIG. 1 ) with at least one, some, or all of the gas flow regulator valves 21, the shut-off valve 37, the dosing unit 28, and the vibration unit 39. The control unit 41 is configured to control the gas flow regulator valves 21 to allow gas flow through only one selected transfer line 15 at a time. Once a stable gas flow is established through the selected transfer line 15, the control unit 41 is configured to open the shut-off valve 37 of the manifold branch 35 connected to the selected transfer line 15 at its manifold outlet 38, thereby allowing the raw material powder 6 to drop into the gas flow of the selected transfer line 15 for delivery to the associated additive manufacturing device 3.

[0049] The embodiment shown in Figures 2 to 5a and 5b illustrates a system 5 that is preferably implemented in practice. The control unit 41 and the vibration unit 39 are not shown in Figures 2 to 5a and 5b. The six conveying lines 15 extend parallel to one another in the y direction within a common, substantially horizontal xy plane and branch off from the pump outlet line 13. The supply manifold 30 is vertically disposed above the parallel conveying lines 15. The dosing unit 28 includes a screw conveyor extending along an axis R inclined relative to the vertical z axis. The screw conveyor receives the raw material powder 6 from the bottom outlet of the reservoir 7 (not shown in Figure 2) and conveys the raw material powder obliquely upward along the axis R to a manifold inlet 32 at the top of the supply manifold 30 (see Figure 4). The raw material powder 6 is conveyed through the dosing unit 28 in a controlled manner at a predetermined conveying speed. The control unit 41 controls the dosing unit motor 43 that drives the screw conveyor.

[0050] The raw powder falls into the manifold inlet 32 and further into the lower feed manifold 30, where it splits into six manifold branches 35 at a pipe branch 33. The pipe branches 33 have sixfold rotational symmetry about the vertical central axis of the manifold inlet 32, as seen in FIG. 3 . The manifold branches 35 split from the pipe branch 33 at an upper inclined section 45 and bend into a lower vertical section 47 positioned vertically above the associated conveying line 15. The manifold branches 35 terminate at their manifold outlets 38 where they enter their respective conveying lines from above. The manifold branches 35 are bent or tilted in the gas flow direction (y-direction) to impart a momentum component in the gas flow direction (y-direction) to the raw powder 6 before it drops into the gas flow of the conveying line 15.

[0051] Each manifold branch 35 includes a shutoff valve 37 on its upper inclined section 45. The shutoff valve 37 is preferably a butterfly valve actuated about an actuator axis C. The valve body 51 (see FIG. 5b) is actuable about the actuator axis C, which extends substantially perpendicular to the longitudinal axis D of the inclined section 45. The actuator axis C and the longitudinal axis D of the inclined section 45 span an imaginary vertical plane, e.g., an imaginary plane CD inclined relative to zx or xz. This allows the shutoff valve 37 to be positioned more compactly. Furthermore, because the actuator axis C is slightly rotated about the axis D, the raw powder can slide under the open valve body 51, which is less likely to cause an obstruction (see FIG. 5b). A horizontal axis C would be ideal in this regard, but this would require lateral space and increase the distance from the shutoff valve 37 to the pipe branch 33. Therefore, rotating the actuator axis C relative to axis D by 10 to 80 degrees relative to the perpendicular zD plane is a favorable compromise.

[0052] At each of the manifold inlets 32 and the vertical sections 47 of the manifold branches 35, the supply manifold 30 is provided with vibration damping elements 49 in the form of flexible pipe sections in order to isolate the supply manifold 30 in terms of vibrations from the dosing units 28 (not shown in Figures 2 to 5a and 5b) and the connected conveying lines 15. This ensures that vibrations generated by the vibrating units 39 are not transmitted undampened from the supply manifold 30 towards the dosing units 28 and / or conveying lines 15.

[0053] As can be seen in Figure 3, the vertical sections 47 of the manifold branches 35 are located at the corners of an imaginary horizontal hexagon.

number

[0054] The transport of raw material powder 6 through system 5 is shown in Figures 4 and the cutaway views of Figures 5a and 5b. When all six shut-off valves 37 are closed, supply manifold 25 is filled with raw material up to manifold inlet 32 as it is filled by dosing units 28. As shown in Figure 5b, opening one of the shut-off valves 37 causes the raw material powder to drop and / or slide along manifold branch 35 into the gas flow of conveying line 15, which immediately transports the raw material powder toward additive manufacturing apparatus 3. The distance between the shut-off valve 37 and pipe branch 33 defines a fixed volume within inclined section 45 of manifold branch 35, which remains filled with raw material powder as long as the associated shut-off valve 37 is closed. To minimize this volume, shut-off valves 37 are positioned as close as possible to pipe branch 33. [Explanation of symbols]

[0055] 1 Additive manufacturing equipment 3 Additive manufacturing equipment 5. System for distributing raw powder 6 Raw material powder 7 Reservoir 9 Gas circulation loop 11 Gas flow driver 13 Pump outlet line 15 Conveyor line 17 Separator 19 Gas return line 21 Gas flow control valve 23 Pump inlet line 25 Vacuum Conveyor 27 Sieve 28 dosage units 29 Unused raw material powder supply section 30 Supply Manifold 31 Raw material powder recycling system 32 Manifold inlet 33 Pipe branch 35 Manifold branch 37 Shut-off valve 38 Manifold outlet 39 Vibration Unit 41 Control Unit 43 Dosing unit motor 45 Sloped part of manifold branch 47 Vertical section of manifold branch 49 Vibration damping elements 51 Valve body γ angle h distance

Claims

1. A system (5) for distributing raw material powder (6) from a reservoir (7) of raw material powder to a plurality of at least two additive manufacturing devices (3) for additive manufacturing, the system (5) comprising at least one gas flow driver (11) and at least two conveying lines (15) for conveying the raw material powder (6) to the at least two additive manufacturing devices (3) by gas flows driven by the at least one gas flow driver (11), The system comprises: at least two shut-off valves (37) and a supply manifold (30) for supplying the raw material powder (6) to the at least two conveying lines (15); The supply manifold (30) a valve (37) configured and arranged to selectively direct the raw material powder (6) to one of the at least two conveying lines (15); Each of the at least two shut-off valves (37) a supply manifold (30) arranged in the supply manifold (30) and configured to selectively open and close to selectively supply the raw material powder (6) to the at least two conveying lines (15); A system (5).

2. The supply manifold (30) a manifold inlet (32) for receiving the raw powder (6) from the reservoir (7); a pipe branch (33) branching into at least two manifold branches (35); at least two manifold outlets (38) each connected to one of said at least two conveying lines (15); Equipped with Each of said at least two manifold branches (35) connecting said manifold inlet (32) to one of said at least two manifold outlets (38); Each of the at least two shut-off valves (37) a valve disposed in association with one of the at least two manifold branches (35) and configured to selectively open and close the associated manifold branch (35); A system (5) according to claim 1.

3. 3. The system (5) of claim 2, wherein the pipe branch (33) is configured to be located at an elevation higher than the at least two manifold outlets (38), and the raw material powder (6) is conveyed through the at least two manifold branches (35) primarily by gravity.

4. 4. The system (5) of claim 1, wherein the supply manifold (30) is configured to be positioned above each portion of the at least two conveying lines (15), and each manifold outlet (38) leads to the portion of one of the at least two conveying lines (15) substantially from above.

5. 2. The system (5) of claim 1, wherein the supply manifold (30) is configured to discharge the raw material powder (6) into the at least two conveying lines (15) with a momentum component parallel to a conveying direction (y) along the conveying lines (15).

6. the supply manifold (30) comprises a pipe branch (33) which branches into at least two manifold branches (35); Each of the at least two manifold branches (35) comprises an inclined portion (45) inclined at an angle of 20 to 70 degrees relative to a central vertical axis of the manifold inlet (32). A system (5) according to claim 1.

7. each of the at least two shut-off valves (37) is disposed in an inclined portion (45) of one of the at least two manifold branches (35) of the supply manifold (30) and comprises a valve body (51) operable about an actuator axis (C) substantially perpendicular to a longitudinal axis (D) of the inclined portion (45) of the manifold branch (35); the actuator axis (C) and the longitudinal axis (D) of the inclined portion (45) of the manifold branch (35) extend in an imaginary plane (CD) that is inclined with respect to an imaginary vertical plane (zD); A system (5) according to claim 1.

8. further comprising a dosing unit (28); the dosing unit (28) comprises a conveying mechanism for conveying a controlled flow of the raw material powder (6) from the outlet of the reservoir (7) to a manifold inlet (32); A system (5) according to claim 1.

9. The system (5) of claim 1, wherein the at least two isolation valves (37) are configured to open only one of the at least two isolation valves (37) at a time.

10. 2. The system (5) of claim 1, further comprising a vibration unit (39) for shaking and / or vibrating the supply manifold (30) to promote the fall of the raw material powder (6) through the supply manifold (30).

11. 2. The system (5) according to claim 1, wherein the supply manifold (30) comprises at least one vibration damping element (49) for damping the propagation of vibrations from the supply manifold (30) to the at least two conveying lines (15) and / or towards the reservoir (7).

12. 2. The system (5) of claim 1, wherein the at least two conveying lines (15) do not have a gas flow regulating valve (21) downstream of the supply manifold (30) and upstream of the at least two additive manufacturing devices (3).

13. the at least two conveying lines (15) being part of a gas flow circulation loop (9); 2. The system (5) of claim 1, wherein the gas flow driver (11) is configured to drive a gas flow circulating in the gas flow circulation loop (9).

14. further comprising at least two gas flow regulating valves (21); each of the at least two gas flow regulating valves (21) associated with one of the at least two conveying lines (15) and selectively regulating the gas flow in the associated conveying line (15); the at least two gas flow regulating valves (21) are arranged downstream of the at least two additive manufacturing devices (3) and upstream of the supply manifold (30); A system (5) according to claim 1.

15. 1. A method for distributing raw material powder (6) from a reservoir (7) of raw material powder to a plurality of at least two additive manufacturing devices (3) for parallel additive manufacturing of three-dimensional workpieces, comprising: Selectively adjusting gas flow in at least two conveying lines (15); each of the at least two conveying lines (15) being associated with one of the at least two additive manufacturing devices (3), and conveying the raw material powder (6) to the associated additive manufacturing device (3) by the gas flow; selectively opening and closing at least two shut-off valves (37) in the supply manifold (30); each shut-off valve (37) associated with one of the at least two conveying lines (15) to selectively drop raw material powder into the gas stream of the associated conveying line (15); The method includes:

16. 16. The method of claim 15, further comprising selectively adjusting the gas flow before any one of the at least two isolation valves (37) is opened.

17. The gas flow is selectively regulated by at least two gas flow regulating valves (21); each of the at least two gas flow regulating valves (21) associated with one of the at least two conveying lines (15) to selectively regulate the gas flow in the associated conveying line (15); the at least two gas flow regulating valves (21) are arranged downstream of the at least two additive manufacturing devices (3) and upstream of the supply manifold (30); 17. The method of claim 15 or 16.

18. A method as described in claim 15, wherein the gas flow is selectively adjusted to be constant within the associated conveying line (15).

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