DE102021212698A1 - Process for the series production of workpieces using a powder bed-based, additive manufacturing process for metallic materials - Google Patents

Abstract

The invention relates to a method for the series production of workpieces (18) using a powder bed-based additive manufacturing method for metallic materials in a production line (10) or on a rotary table (130) that can be moved about an axis of rotation (132). According to the method, at least the following method steps are carried out: a) Introduction of workpieces (18) into at least one secondary chamber (22, 24, 134) which is subject to inerting (100) with a position detection step (88) and a position correction (90) of the workpiece (18) , b) transferring the workpiece (18) prepared according to a) into a main chamber (20) subject to inerting (100), exposure (120) of a structure of the workpiece (18) by means of a laser process (80) and production (114) of an additive Layer on the workpiece (18) within the main chamber (20), c) movement (92) of the workpiece (18) from the main chamber (20) into one of the secondary chambers (22, 24) and de-powdering (94) of the workpiece (18), d) during method steps b) and c) a continuous circulation (72) of a powdery, additive building material takes place, so that a reprocessing (106, 108, 110, 112) of the powdery, additive building material is achieved.

Description

technical field

The invention relates to a method for the series production of workpieces using a powder-bed-based, additive manufacturing method for metallic materials, which can be carried out either on a production line or on a rotary table that can be moved about an axis of rotation.

State of the art

DE 10 2019 109 655 A1 refers to a process for the additive manufacturing of at least one component with defined component properties. At least one certified data record is provided, which contains component properties that are certified by a provider for an additive manufacturing process of at least one specific component, component-specific parameters and/or system-specific parameters and/or process-specific parameters. At least one additive manufacturing process is used for the additive manufacturing of at least one specific component with defined component properties on the basis of the at least one certified data set.

DE 10 2019 119 747 A1 relates to an additive manufacturing learning model creation device. Thus, a manufacturing condition determination device for moldings to be manufactured by additive manufacturing and a state estimating device for moldings to be manufactured by additive manufacturing are presented. An additive manufacturing learning model creating device is applicable to a method of making a molded article by irradiating a light beam onto layered metal powder and heating the metal powder. The additive manufacturing learning model creating device creates a learning model for determining a manufacturing condition or estimating a molding state by machine learning using the manufacturing condition and the molding state as learning data. The fitting state is related to a fitting when the light beam is emitted or after the light beam is emitted.

DE 11 2016 002 386 T5 refers to a manufacturing machine. A manufacturing machine is capable of subtractive manufacturing and additive manufacturing of a workpiece. The manufacturing machine includes a first headstock and a second headstock disposed in a first machining area and configured to hold a workpiece. A lower tool holder and a tool spindle are provided, which are arranged in the first machining area and are configured in such a way that a tool can be held, which is used for the subtractive machining of the workpiece. An additive manufacturing head is provided, disposed in a second processing area, and a robotic arm configured to hold a workpiece and transport the workpiece between the first processing area and the second processing area. The additive manufacturing head is configured to add a material to a workpiece while holding a robotic arm during additive manufacturing of the workpiece. A manufacturing machine is configured accordingly so that both subtractive manufacturing and additive manufacturing of workpieces can be implemented.

Presentation of the invention

1. a) Einbringen von Werkstücken in mindestens eine einer Inertisierung unterliegenden Nebenkammer und Durchführen eines Vermessungsschritts sowie eines Lagekorrekturschritts des Werkstücks,
2. b) Überführen des gemäß a) präparierten Werkstücks in eine einer Inertisierung unterliegenden Hauptkammer, Belichtung einer Struktur des Werkstücks mittels eines Laserprozesses und Erstellung einer additiven Schicht am Werkstück innerhalb der Hauptkammer,
3. c) Bewegen des Werkstücks aus der Hauptkammer in eine der Nebenkammern und Entpulverung des Werkstücks,
4. d) wobei während der Verfahrensschritte b) und c) ein pulverartiges, additives Aufbaumaterial innerhalb eines kontinuierlichen Kreislaufs eine Wiederaufarbeitung erfährt.

According to the invention, a method is proposed for the series production of workpieces using a powder bed-based additive manufacturing method for metallic materials in a production line or on a rotary table that can be moved about an axis of rotation, with at least the following method steps being carried out:

1. a) placing workpieces in at least one secondary chamber subject to inerting and carrying out a measurement step and a position correction step of the workpiece,
2. b) Transferring the workpiece prepared according to a) into a main chamber subject to inerting, exposure of a structure of the workpiece by means of a laser process and creation of an additive layer on the workpiece within the main chamber,
3. c) moving the workpiece from the main chamber to one of the secondary chambers and de-powdering the workpiece,
4. d) wherein during process steps b) and c) a powder-like, additive building material undergoes reprocessing within a continuous cycle.

With the method proposed according to the invention, secondary processes can be outsourced to the at least two secondary chambers that are assigned to a main chamber that carries out the actual additive manufacturing process. With the method proposed according to the invention, a significantly higher utilization of the main chamber can be achieved, which the production time concerns; on the other hand, the interventions to be carried out by an operator can be reduced to an indispensable minimum, so that the error rate of the method proposed according to the invention is considerably reduced.

In a further advantageous embodiment of the method proposed according to the invention, the laser process is carried out in the main chamber, to which workpieces are supplied in alternating sequence both from the first secondary chamber and from the second secondary chamber. Through this alternating loading of the main chamber, the cycle times can be significantly improved and the capacity utilization of the production line can be significantly increased.

In an advantageous embodiment of the method proposed according to the invention, the workpieces are fed via workpiece carriers of a transport system in the transport direction, or a workpiece is fed by moving a rotary table about an axis of rotation, the rotary table along a stationary main chamber, at least one first and second secondary chamber and optionally passing a third side chamber.

In an advantageous embodiment of the method proposed according to the invention, the workpieces are processed in parallel in the secondary chambers assigned to the main chamber, with workpiece position measurement, position correction, inerting, depowdering, handling and quality testing of the workpiece being carried out. By dividing processes into the secondary chambers in this way, the actual additive manufacturing process can take place in the main chamber, while straightening and trimming steps as well as quality testing can be relocated to at least two secondary chambers assigned to the main chamber.

In a further advantageous embodiment of the method proposed according to the invention, preheating and cooling stations are integrated in the at least two secondary chambers, via which the workpieces can optionally be tempered.

In a further development of the method proposed according to the invention, a powder conveyor is automatically filled via a silo with a powder-like, additive building material within the continuous circuit according to b) and this is continuously monitored with regard to its residual moisture content, its oxygen content and its qualitative properties via optical units.

In a further advantageous embodiment of the method proposed according to the invention, the optics units, which have an in-coupling window, for example in the upper area of the main chamber, are monitored using a reference light source to determine whether the in-coupling windows are becoming increasingly dirty, so that intervention by an operator or can be done in another way.

In a further advantageous embodiment of the method proposed according to the invention, the main chamber in which the laser process takes place and the secondary chambers are rendered inert with a protective gas, i. H. flushed, with the protective gas being cleaned by means of self-cleaning filters and continuously monitored with regard to differential pressure, its oxygen content and its residual moisture content.

In a further advantageous embodiment of the method proposed according to the invention, the workpieces can be adjusted in the Z-direction on the individual workpiece carriers of the workpiece transport system; In addition, changes in length and/or tolerances that occur during operation can be compensated for so that there is no reject processing.

In an advantageous development of the method proposed according to the invention, the workpieces are depowdered by depowdering units, in particular pivoting suction/blowing hoods, which are lowered onto the workpiece carrier provided with at least one workpiece.

In an advantageous development of the manufacturing method proposed according to the invention, powdery additive build-up material remaining on the workpiece is whirled up by flushing protective gas into the suction/blast hood lowered onto the workpiece and sucked out of a space between the workpiece carrier and the suction/blast hood by the applied negative pressure. The extracted powder material can then be returned to its processing cycle.

In an advantageous development of the method proposed according to the invention, the workpieces are handled within the production line by a portal system and/or workpiece handling units, which advantageously have gripping devices to which a vacuum is applied. Thanks to the vacuum-loaded gripping devices, the workpieces are handled as gently as possible.

In a further development of the method proposed according to the invention, the main chamber and the at least two secondary chambers are connected to one another or separated from one another by chamber separation sluices, the chamber separating sluices realizing gas-tightness of the main chamber and the at least two secondary chambers and also creating laser safety in relation to the main chamber.

Advantages of the Invention

The solution proposed according to the invention, used in particular as part of an SLM process (SLM0020″—Selective Laser Melting), relates to a powder-bed-based, additive manufacturing method for metallic materials. With the solution proposed according to the invention, a significant increase in the cycle times can be achieved in common systems and manufacturing solutions that use the SLM process and have short cycle times. The process time of these productions to be processed as part of the SLM process is usually more than one hour, often more than 24 hours. Current systems are unsuitable for series production with short cycle times of less than 30 minutes or even significantly less than 5 minutes, since the duration of the secondary processes would exceed the cycle times many times over.

The solution proposed according to the invention makes it possible to achieve considerable advantages with regard to the achievable cycle times for the production of series parts with a high degree of variance. The solution proposed according to the invention can also be used for any workpieces that are completed in production times of less than 30 minutes.

The method proposed according to the invention also offers significant advantages for maintaining machine availability by complying with important premises for maximizing component service life and for minimizing consumables. In this context, the considerable minimization of the consumption of protective gas, either Ar or N ₂ , is particularly noteworthy.

In addition, the method proposed according to the invention can be automated to a large extent and is therefore extremely low-maintenance.

The procedure proposed according to the invention results in a strict division of the individual processes into main chambers and a number of secondary chambers, which are each connected to one another by means of transport systems optimized for requirements. Furthermore, parallel processing of secondary processes and main processes can be achieved in an advantageous manner. Two or more secondary chambers can be assigned to a main chamber, in which essential secondary processes such as measuring the position of the workpiece, rendering inert, depowdering, quality testing or handling of the respective workpiece are carried out.

Furthermore, preheating and cooling stations can advantageously be inserted into the two or more secondary chambers, so that the workpiece can be tempered in a process-optimized manner. The approach proposed according to the invention maximizes the main time share within the main chamber, which has the largest share of costs due to the optical production components, and operator intervention, on the other hand, is minimized, so that operating errors and thus faulty production can be largely ruled out.

The method proposed according to the invention makes it possible to automate the feeding of the powdery, additive building material in an inert manner by means of a vacuum conveyor from a silo. The filling level of the powder-like, additive building material can be continuously monitored within a storage container inside or outside the system; the same applies to relevant parameters such as its residual moisture content and oxygen content. As a result, a reduction in the quality of this material can be detected in good time and a timely replacement can be carried out in the event that this material no longer meets the required quality criteria.

In the method according to the invention, coupling windows for optical components can advantageously be monitored with regard to their degree of soiling, which is done using a reference light source.

The inert gas still circulating in the system is filtered by self-cleaning filters. The protective gas is continuously monitored with regard to its differential pressure, its oxygen content and its residual moisture content, while separated dust is automatically disposed of.

Workpiece carriers used in the production system proposed according to the invention have a Z-adjustment and, if required, a leveling unit in order to compensate for length deviations and tolerances introduced by the workpieces over the course of the operating time. A measurement of the workpiece position is recorded before each SLM process in one of the side chambers and mechanically and optically during the process compensated. The workpiece carrier is advantageously designed oversized to absorb process emissions, especially smoke and spatter, which cannot be completely removed by the flow of protective gas, and to remove them from the chamber after the end of the SLM process, so that the main chamber in which the actual laser construction process is carried out is only exposed to a small amount of contamination.

Advantageously, the depowdering, i. H. the removal of excess powder-like, additive build-up material from the workpiece by means of a suction/blowing hood, which is arranged in such a way that it can be lowered onto the workpiece carrier receiving the workpiece. By blowing in protective gas, the construction material is whirled up and sucked out of the space between the hood and the workpiece carrier by the applied negative pressure. Alternatively or additionally, suction devices can be attached to the powder collection areas on the workpiece carrier in order to efficiently and reliably remove the powdery, additive build-up material. The removed build-up material can be transported inertly to a screening system and fed back into the circuit of build-up material after screening.

The workpieces are handled within the production line by handling systems, which preferably include vacuum grippers. The workpiece carriers always remain in the production line, while a separate transport system is available for transporting the workpieces outside of the production line.

The at least two secondary chambers and the main chamber of the production line are separated from one another via chamber separating sluices or connected to one another by actuating them. To move a workpiece in and out, a workpiece carrier is lifted from a conveyor belt and pressed against the underside of a slide flange so that a seal is guaranteed. The residual oxygen content of the external volume can thus be adjusted with little protective gas expenditure before the slide is opened to insert and remove the workpiece.

The method proposed according to the invention can be implemented both on a production line with a changeover principle and on a rotary table system. The production line offers very high accuracies for high-quality production.

character list

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

• 1 eine schematische Darstellung eines Anlagenaufbaus einer Fertigungsstraße,
• 2 nebeneinanderliegend angeordnete Nebenkammern beidseits einer Hauptkammer,
• 3 Funktionsstruktur des erfindungsgemäß vorgeschlagenen Verfahrens nach dem Wechselprinzip und
• 4 eine Funktionsstruktur des erfindungsgemäß vorgeschlagenen Verfahrens gemäß dem Rundtischprinzip

Show it:

• 1 a schematic representation of a plant structure of a production line,
• 2 secondary chambers arranged side by side on both sides of a main chamber,
• 3 Functional structure of the method proposed by the invention according to the alternating principle and
• 4 a functional structure of the method proposed according to the invention according to the round table principle

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference symbols, with a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a schematic representation of a production line for carrying out the method proposed according to the invention for the series production of workpieces 18. In the production line 10 according to the representation in 1 the exchange principle is implemented, in which a main chamber 20, in which the actual SLM process takes place, is assigned to at least two secondary chambers 22, 24. Workpieces 18 are supplied via workpiece carriers 16 of a transport system 12 which convey workpieces 18 in the transport direction 14 . By using three chambers, as in 1 shown, ie the main chamber 20, the first secondary chamber 22 and the second secondary chamber 24, while in the main chamber 20 workpieces 18 are built up additively, in one of the secondary chambers 22, 24 a preparation and post-processing for the following construction process can take place. There are deviations from the representation according to 1 Several chambers are possible if the cycle times are very short and, despite parallelization, the secondary processes last longer than the actual build-up process taking place in the main chamber 20 according to the SLM method.

In the representation according to 1 a production line 10 is described in which the main chamber 20 is assigned the first secondary chamber 22 and the second secondary chamber 24 . Once the core process, ie the actual build pro process within the scope of the laser process 80 and the secondary processes taking place in the secondary chambers 22, 24 have been completed, the workpiece carrier 16 with the finished workpieces 18 moves from the main chamber 20 into the first secondary chamber 22, for example, while a prepared workpiece 18 is brought up from the second secondary chamber 24 a workpiece carrier 16 is moved into the main chamber 20. The finished build-up order for the workpiece 18 can thus be post-processed and a new build-up order can be prepared, while the process of building up further workpieces 18 is continued in the actual main chamber 20 . After the processes have been completed again, the now newly prepared construction job moves from the first secondary chamber 22 into the main chamber 20, while at the same time the finished workpiece 18 moves from the main chamber 20 into the second secondary chamber 24 assigned to it and arranged on the right-hand side.

In order to optimize the permissible process times, an inerting 100 can be outsourced from the secondary chambers 22, 24 to upstream or downstream locks, while the main and secondary processes are already taking place in the main and secondary chambers 20, 22, 24.

According to the illustration 1 shows that the transport system 12 comprises rails 26, on which the workpiece carriers 16 with the workpieces 18 received on them are transported between the individual chambers 20, 22, 24. Furthermore, the in 1 Schematically illustrated production line 10 workpiece handling units 28 and at least one de-powdering unit 30, which is assigned to the first secondary chamber 22 in this case. The powder removal unit 30 can be designed as a pivotably arranged suction/blowing hood 32 which can be pivoted in such a way that it rests on a cover 34 of the workpiece carrier 16 and encloses a finished workpiece 18 held on the workpiece carrier 16 .

According to the illustration 1 shows that there is an open sluice 36 for partial introduction and a closed sluice is indicated by position 38 .

From the schematic representation of the production line 10 according to 1 also shows that a chamber separation lock 40, 42 is provided between the main chamber 20 and the two secondary chambers 22, 24. This allows the main chamber 20 to be separated from both the first secondary chamber 22 and the second secondary chamber 24 or reconnected thereto in order to enable workpieces 18 to be transferred in a protective gas atmosphere.

Numeral 44 designates another depowdering unit shown in FIG 1 is arranged in the second auxiliary chamber 24 . Reference number 46 designates a lifting position with a sliding flange, via which finished workpieces 18 can be removed.

A powder conveyor 48 and a first optics unit 50 and a second optics unit 52 are located above the main chamber 20. These are arranged above the roof of the main chamber 20 in such a way that they can monitor a processing position 54 of a workpiece carrier 16 with a workpiece 18 to be built up.

2 shows a representation of the production line 10 as shown in FIG 1 in frontal view. In the first secondary chamber 22 and the second secondary chamber 24 there are position detection cameras 56 on their roofs, which are used via an information line 58 to detect the position of the workpieces 18 on the workpiece carriers 16 . Below the powder conveyor 48 is a powder supply 60 of a powder-like, additive building material. The powder supply 60 is accommodated in a funnel-shaped container, which is assigned a dosing unit. The powder-like, additive build-up material is encapsulated via a powder application unit 62 and fed to the workpiece 18 for layer build-up by a protective gas supply or discharge line 64, so that one or more layers can be built up additively in the Z-direction. The workpiece 18 is held on the workpiece carrier 16 during the assembly process. While the depowdering unit 30, designed as a swiveling suction/blowing hood 32, is shown in its upright position in the first secondary chamber 22, it is located in the second secondary chamber 24 as shown in FIG 2 in the lowered state. The main chamber 20 is separated from its secondary chambers 22, 24 via the chamber separation locks 40, 42, so that in each of the chambers, ie the main chamber 20 and the two secondary chambers 22, 24, there is gas tightness 102, ie an inert gas atmosphere.

The two secondary chambers 22, 24 are each connected via a rail 26 with one or more independent workpiece carriers 16 or two individual axis systems with the main chamber 20 shown here in the middle, in which the laser process 80 takes place. The two secondary chambers 22, 24 are separated from one another by the chamber separation locks 40, 42 in order to keep the volume of protective gas moved as small as possible. Coupling windows for the optical units 50, 52 are provided for reliable series production. About the arranged on the roof of the main chamber 20 two optics units 50, 52 and not here In the coupling window shown in more detail, laser radiation is coupled, as a result of which the necessary laser power is coupled into the main chamber 20 serving as a process chamber for carrying out the laser process 80 . A protective gas flow is generated by protective gas inlets and outlets 64, which allows the process emissions to flow away from the coupling windows in order to minimize their contamination.

On the sides of each chamber, i. H. of the main chamber 20 and the two secondary chambers 22, 24, sliders can be arranged in order to separate the main chamber 20 from the two secondary chambers 22, 24 shown here while the SLM process is being carried out. The workpiece carrier 16 for accommodating the workpieces 18 can have its own Z adjustment with a small stroke and clamping technology in order to fix the individual workpieces 18 in place. The structure of the workpiece carrier 16 is seated on an axis in such a way that it moves between the main chamber 20 and one of the two secondary chambers 22 , 24 . When moving along this axis or the rails 26, the Z-axis can be lowered to the lowest position in order to be able to dive under other existing components if necessary. With regard to a depowdering 94, the Z-axis is used in order to be able to bring about a seal against the depowdering unit 30 in the form of a suction/blowing hood 32.

The powder supply 60 is held statically in the main chamber 20 and is filled from an external silo. The powder supply 60 is filled via a vacuum conveying system, cylinder and optics in order to be able to provide the powder-like, additive building material in the main chamber 20 that is required for carrying out the laser process 80 . The powder-like, additive build-up material is metered from the top onto the workpiece carrier 16 or the workpiece 18 accommodated therein, and the powder application unit 62 is set to the layer density required in each case. For this purpose, the workpiece carrier 16 can cover a distance to the side so that the powder-like, additive building material is deposited directly on the workpiece carrier 16 and not on parts of the main chamber 20 . Excess powder-like, additive build-up material is pushed by the application mechanism into a powder overflow to be arranged laterally on the respective workpiece carrier 16. If the need arises, either to optimize the process time or to process several powder-like, additive building materials, a second powder supply including dosing can be arranged symmetrically to the middle position.

While the laser process 80 is being carried out, it is possible for the workpiece carrier 16 to move along the rail 26 in order to minimize positional errors in the optics units 50, 52. The exact process management and the division are dependent on the respective configuration of the workpiece 16. In the case of the secondary processes taking place in the secondary chambers 22, 24, a distinction must be made between upstream and downstream secondary processes. However, both types take place equally in the two secondary chambers 22 and 24 serving as secondary process chambers, since the workpieces 18 do not pass through the stations from left to right, but from front to back.

Based on 3 and 4 are the secondary processes in the secondary chambers 22, 24 according to the 1 and 2 expire, or on an in 4 illustrated rotary table 130, which is movable about an axis of rotation 132, explained.

According to 3 A process sequence 70 takes place in that several sub-processes overlap one another. Reference number 72 designates, for example, a circuit of the powdery, additive building material. Reference number 74 denotes a protective gas circuit, whereas reference numbers 76 and 78 denote workpiece paths which the workpieces 18 take in the context of upstream and downstream processes, starting from and including the secondary chambers 22, 24, before or after the laser process 80 running in the main chamber 20 .

As a preceding step, it should be mentioned that after a workpiece preparation step 82 and a workpiece supply step 84 , a workpiece position measurement 88 takes place in a workpiece holding step 86 . A large map is measured for reference markers on the workpiece carrier 16. This is done by optical measurement, with the correction values for processing these workpieces 18 being offset against those provided by the optics, provided the workpiece 18 represents a final component. Otherwise, the data obtained in the workpiece measurement step 88 is used to align the workpiece 18 relative to the powder application 62 using a reference coordinate system. If the spatial positioning of the workpieces 18 is not reproducible, the workpiece carrier 16 can have a leveling unit in order to precisely adjust the position of the workpiece 18 in space to the reference plane required by the optics on the powder application unit 62 .

As a further, downstream step, which takes place in the two secondary chambers 22, 24, the focus is on de-powdering 94. Here, the surface of the workpiece carrier 16 is pressed with the Z-axis of the workpiece 18 from below against a frame. At the same time, as Entpul Verungeinheit 30 serving pivotable suction / blowing hood 32 on the frame. The suction/blowing hood 32 is provided with protective gas inlets and suction; alternatively, powder overflows with an additional suction connection can be provided additionally or separately. By blowing in protective gas, the powdery additive build-up material possibly still adhering to the workpiece 18 is whirled up and sucked out of the volume between the hood and the workpiece carrier 16 together with the swiveling suction/blowing hood 32, which is now slipped over the workpiece 18. Any contamination that remains on the workpiece carrier 16 or surrounding components will accumulate over the large number of workpieces 18 and is to be avoided accordingly in order to keep the cleaning effort due to maintenance and the associated downtimes low. The chambers, ie the main chamber 20 and the secondary chambers 22, 24 are designed in such a way that space is available for possible additional secondary processes, such as a second cleaning step or a quality check that may still have to be carried out.

The handling of the workpieces 18 can be oriented perpendicularly to the main or secondary process axis, while the movement of the workpiece carrier 16 on the rails 26 takes place in parallel. The supply of parts to the individual workpiece carriers 16 with prefabricated workpieces 18 can be carried out via a separate conveyor belt, for example on the front side of the production line 10, as shown in 1 is shown schematically, take place.

To bring in the workpieces 18, the workpiece carriers 16 of the transport system 12 can be lifted out of a conveyor belt or rails 26 and pressed against the underside of one of the two secondary chambers 22, 24. This allows automatic sealing to the ambient atmosphere and minimization of the volume to be inerted, i. H. of that volume which is to be placed and kept under a protective gas atmosphere. Pre-inerting can also be carried out by letting in protective gas during the docking process. As soon as the necessary oxygen content is reached, one of the chamber separation locks 40, 42 opens to the corresponding secondary chamber 22, 24 and the workpiece 18 can be placed on the workpiece carrier 16 of the rail 26 and clamped there, for example via the workpiece handling unit 28 by means of a vacuum gripper or the like or via a portal gripper become. Due to the series connection of pick-up or docking positions, care must be taken to ensure that a workpiece carrier 16 including a workpiece 18 is always let through to the respective secondary chamber 22, 24, so that workpieces 18 can always be made available and pre-processed there. As soon as a workpiece 18 is removed, the respective chamber separation lock 40, 42 is closed and the workpiece carrier 16 is lowered onto the conveyor belt. From there, the workpiece carrier 16 can be transported to the rear of the system.

An output of the finished workpieces 18, for example steps 96, 98 in the representation according to FIG 3 and 4 , is essentially the same. For this purpose, an empty workpiece carrier 16 is lifted out of the respective conveyor belt or rail 26 on the rear side of the system for transport purposes and pressed against a rear side of a respective secondary chamber 22 , 24 . After the respective secondary chamber 22, 24 has been rendered inert 100, the respective chamber separation lock 40, 42 can be opened and a finished workpiece 18 can be placed on it and thus conveyed out of the system.

Regarding the 3 and 4 it should also be mentioned that reference numeral 86 designates workpiece holding steps and reference numeral 92 designates workpiece movement steps. If necessary, a correction step 90 for correcting the position of the workpieces 18 may be necessary.

As part of the inerting 100, the chamber separation locks 40, 42 ensure their gas tightness 102 with regard to the two secondary chambers 22, 24 and with regard to the main chamber 20, in which the laser process 80, d. H. the actual construction process takes place, the laser safety of which is 104 established.

As part of circuit 72 for reprocessing depowdered, additive construction material, this is sieved in step 106 before it reaches, for example, powder supply 60 with a dosing unit as part of a material supply 108 . The powder reservoir 60 holds the powdered, sieved additive build material as part of a material holding step 110 and prior to use as part of a metering step 112 is metered as required by the layering step 114 prior to being built up on the workpiece 18 as part of a new Z-direction layer .

The workpiece 18, which is located in the main chamber 20 and is to be built up in the Z-direction, is held on the workpiece carrier 16 and, depending on the intensity shaping step 116 and the laser 2D deflection 118, is prepared beforehand as part of an exposure step 120 in such a way that, as in 2 indicated, as part of the protective gas supply and discharge 64, the corresponding layer in Layer manufacturing step 114 can be built up in the Z-direction.

In relation to 4 It should be mentioned that, according to the rotary table principle, the workpiece 18 to be assembled always remains in the tool holding step 86 and the rotary table 130 moves according to the set direction of rotation 136 to represent the workpiece feed on the main chamber 20, the two secondary chambers 22, 24 and, if necessary, along a further, third Auxiliary chamber 134, where loading and unloading takes place, moves.

For the sake of completeness, it should also be mentioned that a protective gas, such as argon or nitrogen, circulates within the framework of the protective gas circuit 74, which gas passes through a protective gas filter or circulation 122 for reprocessing. The method proposed according to the invention can increase the volume of the in the individual chambers, d. H. the main chamber 20 or the two secondary chambers 22, 24 and optionally within the further, third secondary chamber 134 stored protective gas volume are kept to a minimum.

The invention is not limited to the exemplary embodiments described here and the aspects highlighted therein. Rather, within the range specified by the claims, a large number of modifications are possible, which are within the scope of expert action.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102019109655 A1 [0002]
• DE 102019119747 A1 [0003]
• DE 112016002386 T5 [0004]

Claims (13)

Method for the series production of workpieces (18) using a powder bed-based, additive manufacturing method for metallic materials in a production line (10) or on a rotary table (130) that can be moved about an axis of rotation (132), with at least the following method steps: a) Introduction of workpieces (18) into at least one secondary chamber (22, 24, 134) subject to inerting (100) with a position detection step (88) and a position correction (90) of the workpiece (18), b) Transferring the workpiece (18) prepared according to a) into a main chamber (20) subject to inerting (100), exposure (120) of a structure of the workpiece (18) by means of a laser process (80) and production (114) of an additive layer on the workpiece (18) within the main chamber (20), c) movement (92) of the workpiece (18) from the main chamber (20) into one of the secondary chambers (22, 24, 134) and de-powdering (94) of the workpiece (18), d) wherein during method steps b) and c) a powder-like, additive building material runs through a continuous cycle (72) in which it runs through various reprocessing stages (106, 108, 110, 112). procedure according to claim 1 , characterized in that the main chamber (20), in which the laser process (80) is carried out, is loaded alternately from the first secondary chamber (22) or the second secondary chamber (24) with workpieces (18). Procedure according to claims 1 and 2 , characterized in that the workpieces (18) are fed via the workpiece carrier (16) of a transport system (12) in the transport direction (14), or the workpieces are fed by rotating the rotary table (130) about the axis of rotation (132) along the main chamber (20 ), the first and second secondary chambers (22, 24) and a third secondary chamber (134). Procedure according to claims 1 until 3 , characterized in that the workpieces (18) are processed in parallel in the secondary chambers (22, 24, 134) assigned to the main chamber (20) and workpiece measurement (88), position correction (90), inerting (100), powder removal (94), a handling and a quality check of the workpieces (18) is carried out. Procedure according to claims 1 until 4 , characterized in that the at least two secondary chambers (22, 24, 134) contain preheating and cooling stations with which the workpieces (18) are tempered. Procedure according to claims 1 until 5 , characterized in that within the continuous circuit (72) of the powder-like, additive building material according to b), a powder conveyor (48) is automatically filled via a silo and the powder-like, additive building material with regard to its residual moisture content, its oxygen content and its quality via optical units (50 , 52) is continuously monitored. Procedure according to claims 1 until 6 , characterized in that the optics units (50, 52) are provided with in-coupling windows which are monitored for contamination by means of a reference light source. Procedure according to claims 1 until 7 , characterized in that the main chamber (20), in which the laser process (80) takes place, and the at least two secondary chambers (22, 24, 134) are rendered inert with a protective gas, the protective gas being filtered by means of self-cleaning filters and continuously with regard to a Differential pressure, its oxygen content and its residual moisture is monitored. Procedure according to claims 1 until 8th , characterized in that the workpieces (18) on the workpiece carriers (16) can be adjusted in the Z direction and length deviations and/or tolerances that occur during operation are compensated for. Procedure according to claims 1 until 9 , characterized in that the depowdering (94) of the workpieces (18) is carried out by depowdering units (30), in particular pivotable suction/blowing hoods (32), which are lowered onto the workpiece carriers (16) provided with at least one workpiece (18). become. Method according to one of Claims 1 until 10 , characterized in that the powder-like, additive build-up material remaining on the workpiece (18) is whirled up by blowing protective gas into the suction/blast hood (32) lowered onto the workpiece (18) and is evacuated from an intermediate space between the workpiece carrier (16) and the suction/blowing hood (32) is sucked off. Method according to one of Claims 1 until 11 , characterized in that the workpieces (18) within the production line (10) by a Portal system and / or workpiece handling units (28) are handled, which comprise vacuum-loaded gripping devices. Method according to one of Claims 1 until 12 , characterized in that the main chamber (20) and the at least two secondary chambers (22, 24, 134) are connected to one another or separated from one another by chamber separation locks (40, 42), which ensure gas tightness (102) of the main chamber (20) and the at least create two secondary chambers (22, 24, 134) and a laser safety (104) of the main chamber (20).

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