Production system comprising an extrusion apparatus and an additional dispensing apparatus for support material, and manufacturing process

Abstract

The invention relates in particular to a production system (S) for additively manufacturing at least one component (1), wherein the production system (S) comprises at least one extrusion apparatus (2) with which component material for manufacturing the at least one component (1) can be applied in a production area (9) in component layers (1S) that follow one another along at least one build-up direction (z). A production system (S) according to the invention comprises, in addition to the at least one extrusion apparatus (2), at least one dispensing apparatus (5) with which, after at least one component layer (1S) has been applied, a free space (91.1, 91.2, 91.3, 91.4) present in the production area (9) and without component material can be at least partially filled with at least one support material.

Description

[0001] AIM128WO Page 1

[0002] NEW AIM3D GmbH Industriestraße 12 18069 Rostock

[0003] Manufacturing system with extrusion device and additional dispensing device for support material and manufacturing process

[0004] Description

[0005] The proposed solution concerns a manufacturing system with an extrusion device for the additive manufacturing of at least one component, as well as an additive manufacturing process.

[0006] Extrusion equipment, such as screw extruders, is primarily used in the mass production of components via injection molding and die casting. In these machines, a screw, an injection nozzle, and a die are typically arranged horizontally. The material, usually in granular or powder form, is generally fed into the rearmost part of the screw extruder, in the so-called feed zone. The material is fed vertically onto the screw via a hopper mounted on a section of the extruder tube. A sufficiently large cross-section in the hopper, which prevents bridging, allows the material to fall onto the screw by gravity and be drawn in. In mass production, three-zone screw extruders are typically used, which draw in the material and convey it to the nozzle.The material is compressed, de-aired, and homogenized. Then, pressure is built up to fill the die.

[0007] The feed zone of the screw extruder is often designed as a pipe section within the extruder housing. A hopper is positioned on this pipe section, through which the material can be fed to the screw (see AIM128WO page 2). The minimum cross-section of the pipe section and hopper must be selected to prevent bridging of the granular material. This is highly dependent on the angle of repose and the coefficient of friction of the bulk material being used.

[0008] German patent DE 10 2014 018 081 A1 describes a 3D printing device for the additive manufacturing of metallic components. This device also utilizes a screw extruder that processes material supplied as granules. In a movable print head of the 3D printing device, the thermoplastic material is extruded layer by layer by means of a vertically arranged screw extruder to create a three-dimensional component.

[0009] In 3D printing devices and related manufacturing systems with at least one extrusion unit designed to process component material in the form of granules, filament, and / or rods, it has been common practice to form support structures using the extrusion unit. These structures support overhanging sections of the component—that is, sections of the component spaced apart from a substrate where no build material is to be placed between them—during the manufacturing process. These support structures must then be removed from the component at the end of the additive manufacturing process. Not only are these removal processes sometimes complex, but the formation of the support structures also results in a significant additional time expenditure for the additive manufacturing process.

[0010] As illustrated in Figures 6A to 6D, for example, using a known additive manufacturing process from the prior art, in a component 1 built up layer by layer, a portion of a support structure 99 is also produced layer by layer in each manufacturing level. In this process, the layer for the support structure 99 may, in some cases, occupy a significantly larger area (per layer) than the area of ​​a layer 1S for the component 1 being manufactured.

[0011] Figure 6A shows a substrate 11 of a prior art additive manufacturing system, which is formed, for example, by a height-adjustable platform. A manufacturing area is virtually defined on the substrate 11, on which a component 1 can be additively manufactured, i.e., layer by layer by 3D printing, for example, from a plastic material, in particular a fiber-reinforced plastic material. In an early phase of the additive manufacturing process shown in Figure 6A, a first AIM128WO page 3

[0012] Component layer 1S is produced using an extrusion device (not shown). For the production of component layer 1S, a component material was continuously extruded as a filament from an extrusion die onto the substrate 11. A first layer of the support structure 99 is formed around component layer 1S. The material for the support structure 99 is provided by a different material, which is also applied to the substrate 11 by the extrusion device. The area of ​​the support structure 99 layer occupies a significantly larger proportion of the manufacturing area 9 than the area of ​​component layer 1S. Therefore, the additive manufacturing of the support structure 99 is associated with a considerable manufacturing time.

[0013] As illustrated in subsequent phases of the manufacturing process in Figures 6B and 6C, the support structure 99 grows along a vertically extending build direction as component 1 is formed piece by piece over further component layers 1S. The support structure 99 is, in part, comparatively complex and, to save material, is formed with hollow chambers. Its formation may therefore require comparatively large adjustment ranges for a print head of the extrusion device.

[0014] To obtain component 1 as shown in Figure 6D at the end of the additive manufacturing process, the support structure 99 must be completely separated from the layer-by-layer built component 1. This separation is also comparatively complex and time-consuming. Furthermore, the extrusion-based material used to form the support structure 99 is not reusable and must be disposed of.

[0015] In conventional additive manufacturing processes and systems that include at least one extrusion unit as part of a 3D printer, efforts to reduce manufacturing costs and time have focused almost exclusively on increasing the extrusion rate of the material and thus the printing speed. However, it has become apparent that this no longer significantly reduces manufacturing costs. Larger layer thicknesses for component layers or support structures are also hardly feasible given the increasing complexity of component designs. The same applies to larger diameters of the extrusion dies, as this would significantly restrict design freedom and / or surface quality. AIM128WO Page 4

[0016] Against this background, there is a need for further improvements in manufacturing systems for the additive manufacturing of components using at least one extrusion device and for corresponding additive manufacturing processes. This is where the proposed solution comes in.

[0017] In a proposed manufacturing system for the additive manufacturing of at least one component, the system comprises at least one extrusion device with which component material for the production of the at least one component can be applied in successive layers along at least one build direction within a manufacturing area. In addition to the at least one extrusion device, the proposed manufacturing system comprises at least one dispensing device with which, after the application of at least one component layer, a free space existing in the manufacturing area without component material can be at least partially filled with at least one support material.

[0018] The proposed solution is based on the fundamental idea of ​​providing a manufacturing system in which, during the additive manufacturing process, at least one support structure for the component is not produced via the extrusion device, but rather using a separate, additional dispensing device. This device places the support material into one or more spaces present in the manufacturing area after the production of at least one component layer. Thus, one or more (at least two) different support materials can be applied to the manufacturing area to support overhanging sections of the component during the subsequent manufacturing process, independently of the extrusion device.The support material can be partially or completely removable at the end of the manufacturing process, thus enabling separation from the component, particularly without mechanical or chemical post-treatment. In particular, the proposed solution incorporates a combination of material extrusion printing and powder printing within a single manufacturing system, and therefore within a 3D printing device, a combination not previously considered in practice.

[0019] An extrusion device of the manufacturing system is understood to be, in particular, a device with at least one extruder screw, which typically runs vertically. However, in the proposed solution, an extrusion device can be configured and designed not only for extrusion-based output of component material, which is fed to an extruder screw, e.g., in the form of granules. Rather, an AIM128WO page 5

[0020] In the proposed solution, the extrusion device is also designed and intended for the dispensing of component material, which is fed to the extrusion device as a filament or in rod form. The component material can be extruded through an extrusion die of the extrusion device, so that by dispensing a strand of component material onto a substrate (solid or generated during the additive manufacturing process), the component to be manufactured is produced layer by layer along at least one build direction. In principle, one build direction can be provided that runs vertically along the manufacturing system during the additive manufacturing process. However, this is by no means mandatory. Likewise, layer by layer of the component along only one build direction is not mandatory.For example, the extrusion device can also be designed with one or more swiveling print heads, each carrying an extrusion nozzle, be intended for assembly line printing, be intended for 3D printing on a surface inclined to the horizontal and / or be combined with a 5-axis (and therefore not just three-axis) adjustment device of the manufacturing system for positioning an extrusion nozzle and / or a support for the manufacturing area.

[0021] The at least one dispensing device can be configured to produce a layer of support material in the at least one existing free space. The support material is thus also applied layer by layer, with the dispensing device being configured and designed to apply a layer of support material after the at least one component layer has been produced from the component material.

[0022] In one embodiment, the manufacturing system is equipped with at least one extrusion device and at least one dispensing device to apply component material for the component to be manufactured and support material layer by layer in at least one free space remaining in the manufacturing area after the component material has been applied, in successive manufacturing levels along the build direction. In one manufacturing level, for example, one layer of component material and at least one layer of support material are applied to the manufacturing area before another layer of component material and at least one layer of support material are applied in a subsequent manufacturing level in the build direction. Thus, in each manufacturing level, for example, the production of a component layer by applying component material (e.g.,by depositing component material strands at various locations within the manufacturing area (using an AIM128WO page 6 or several extrusion dies of at least one extrusion device) and subsequently producing one or more layers of support material in one or more spaces within the manufacturing area where, at least in the current manufacturing level, no component material has been applied. Layers of support material thus grow during the manufacturing process for the production of the at least one additive component to a similar or even the same extent as the component layers, so that at the end of a manufacturing process that can be implemented with one embodiment of the proposed manufacturing system, the at least one component can be embedded in the support material.

[0023] For the proposed solution, it has proven generally advantageous for certain applications if the diameter of the extrusion die of the extrusion device for dispensing the component material is in the range of 0.1 mm to 20 mm, particularly in the range of 0.2 mm to 1.5 mm. The (layer) thickness / height of a component layer to be applied with the extrusion device is, for example, in one embodiment in the range of 0.01 mm to 15 mm, particularly in the range of 0.02 mm to 3 mm or 0.05 mm to 1 mm.

[0024] When support material is applied in layers, especially powdered support material applied in layers, layer thicknesses or layer heights in the range of 0.005 mm to 15 mm, and especially in the range of 0.01 mm to 5 mm or 0.01 mm to 3 mm, have proven advantageous.

[0025] In principle, it is considered advantageous if at least one dispensing device is designed and provided for the application of support material without being based on extrusion. This allows the advantages of an extrusion device for the surface application of the component material to be combined with the advantages of a dispensing device for the application of the support material, without the restrictions that may exist in an extrusion process for the application of the support material.

[0026] In particular, time-consuming extrusion-based printing of support structures can be completely eliminated or at least significantly reduced compared to previously used processes. It is conceivable, for example, that a combination of material extrusion printing and powder printing could be implemented in a proposed manufacturing system. Initial tests of the proposed solution have already shown, for instance, that manufacturing times for components can be reduced to one-quarter of the previous manufacturing time (see page 7 of AIM128WO) if extrusion-based printing of support structures can be completely eliminated and a powdered support material is applied during the manufacturing process by a delivery device within the manufacturing system to support sections of the component being manufactured.

[0027] However, the possibility remains to produce a support structure using at least one extrusion device. Extrusion-based printing of such a support structure may then only be used in conjunction with the application of support material by other means, and thus may only be locally limited.

[0028] The at least one dispensing device can, for example, be configured and designed for applying powdered support material, particularly support material powders with a particle size in the range of 50 pm to 1000 pm. This includes, for example, the application of glass bead powder by the at least one dispensing device. Glass bead powder is significantly more cost-effective compared to component material containing plastic, ceramic, and / or metal, and can also be used, for example, for blasting components for cleaning. Furthermore, glass bead powder is typically non-respirable and non-explosive. Therefore, the use of a proposed manufacturing system in such a configuration also offers significant advantages in terms of handling.Alternatively or additionally, at least one dispensing device may be provided for applying powdered support material made of or containing polymers and / or minerals and / or for applying coated powdered support material.

[0029] In a dispensing device for applying powdered support material, the dispensing device can, for example, be configured and designed for the selective and layer-by-layer application of the powdered support material into at least one cavity (in particular, for each component layer to be produced). For instance, one embodiment of a proposed manufacturing system provides that at least one extrusion device is combined with a selective recoater, whereby the selective recoater selectively introduces powdered support material into areas of the production area not covered with component material. A suitable selective recoater is offered, for example, by Schaeffler Aerosint SA, Belgium. The layer-by-layer application of powdered AIM128WO used here is shown on page 8.

[0030] After the manufacturing process, the support material can be easily separated from at least one component by tapping or blowing it out.

[0031] Instead of a dispensing device that selectively fills voids layer by layer with powdered support material, a dispensing device for applying powdered support material layer by layer in the production area is also conceivable. This device includes a scraping mechanism designed to remove at least a portion of the production area of ​​powdered support material. In such a design variant of a production system, it can therefore be provided that, following the application of a component layer, at least a portion, possibly even a large part, or even the entire production area is coated with powdered support material. Subsequently, the powdered support material is selectively removed from those parts of the production area where another layer of the component material is to be applied.In other words, the wiping device removes powdered support material from that part of the manufacturing area where component material is to be applied subsequently (i.e., in a subsequent manufacturing step) via the at least one extrusion device.

[0032] In one embodiment, a viscoelastic support material can be used instead of powdered support material for filling one or more cavities (layer by layer) during the additive manufacturing process. Alternatively or additionally, a support material containing at least one photopolymer can be used. The at least one dispensing device can therefore be configured and designed for applying viscoelastic support material and / or support material containing at least one photopolymer. A corresponding non-powdered support material can optionally be selectively introduced into the at least one existing cavity in a manufacturing plane via a dispensing device, thus selectively applying it layer by layer.

[0033] The at least one dispensing device can also be configured and designed to dispense a material different from the support material into a free space present in the manufacturing area, in order to specify certain physical properties of the component being manufactured. The additional material applied via the dispensing device can, for example, serve to selectively influence, at least locally, the density, rotational stiffness, thermal conductivity, and / or damping of the component being manufactured (see AIM128WO, page 9). The corresponding material is thus intended to remain on the component after completion of the manufacturing process.

[0034] Alternatively or additionally, it may be provided that support material remains at least partially attached to the finished component, or is intended to remain at least partially attached to the component (i.e., as part of the component), in order to define certain physical properties of the component, such as density, rotational stiffness, thermal conductivity, and / or damping. For example, one design variant may provide that the manufacturing system creates one or more cavities in the finished component, forming an internal and, if necessary, completely closed cavity. Support material may be introduced into this cavity during the additive manufacturing process and remain at least partially enclosed within the cavity of the finished component.The support material remaining in the cavity can, for example, form a balancing mass within the component. This includes, in particular, a design variant in which, during or at the end of the additive manufacturing process, at least some of the support material is removed from a partially or completely closed cavity of the component (for example, by creating an opening to the cavity during the additive manufacturing process or by subsequently creating one, e.g., through drilling, and draining at least some of the powdered support material from the cavity), thus ultimately leaving some of the originally applied support material within the component to influence its physical properties.

[0035] In one embodiment, the manufacturing system additionally includes a surface treatment unit designed and intended for surface treatment of the support material applied in the manufacturing area. With a surface treatment unit of the manufacturing system, at least a portion of the support material applied to each component layer, or an entire layer of applied support material, can be subjected to surface treatment. This includes, for example, the possibility that the surface treatment unit is designed for

[0036] - a thermal melting of support material,

[0037] - a chemical dissolving of support material,

[0038] - the application of an adhesion promoter to support material, AIM128WO page 10

[0039] - the application of a release spray to the support material or the activation of a coating on the support material is planned. A surface treatment system of a manufacturing system can therefore be set up and designed to perform a surface treatment of the support material according to at least one of the aforementioned types. The type of surface treatment depends fundamentally on whether a more adhesive effect of the support material is desired, or whether the surface treatment should, for example, make the support material easier to remove from a substrate supporting the manufacturing area. Within a manufacturing system, several surface treatment units or a surface treatment unit with different uses may also be present, in order to be able to vary the types of surface treatments, for example, for different support materials and / or in areas of a manufacturing level.Surface treatment is a suitable option within the additive manufacturing process, for example, before component material is applied again via at least one extrusion device in the subsequent manufacturing level.

[0040] In principle, the manufacturing area, in which the component material is to be applied (e.g., to a flat surface of the manufacturing system), can be provided by an edge or even a complete enclosure. To allow for greater flexibility in the design of the manufacturing area, it has proven advantageous if the manufacturing area is partially formed from the component material only during the manufacturing process for the at least one additive component. The extrusion device can then be configured and designed to form at least one edge of the manufacturing area from the component material during a manufacturing process for the at least one additive component. This includes, for example, a circumferentially closed edge of the manufacturing area formed by a closed frame made of component material.A border or even a frame enclosing the component, made of component material, can also be produced layer by layer along the build direction in the manufacturing area. A layer of the border is then always produced together with a component layer in the same manufacturing plane, i.e., in the same manufacturing step. In one embodiment, at the end of a manufacturing process, the additively manufactured component is embedded in powdered support material in a box whose side walls were produced layer by layer from component material by the extrusion device. AIM128WO Page 11.

[0041] The proposed solution further relates to a method for the additive manufacturing of at least one component. For the additive manufacturing process, at least one extrusion device is provided, with which component material for the production of at least one component is applied in successive layers along at least one build direction within a manufacturing area. After the application of at least one component layer, at least one free space within the manufacturing area, devoid of component material, is at least partially filled with at least one support material, which supports at least one section of the component during the subsequent manufacturing process.

[0042] By means of support material, for example powdered support material, which is placed separately into at least one free space, an overhanging section of the component can be supported during additive, extrusion-based manufacturing without the need for the extrusion device to form a support structure (although this remains possible).

[0043] A variant of a proposed manufacturing process can be implemented, in particular, with a variant of a proposed manufacturing system. The features and advantages of a variant of a proposed manufacturing system explained above and below therefore also apply to variants of a proposed manufacturing process, and vice versa.

[0044] In one embodiment of a proposed manufacturing process, a powdered support material can therefore be applied layer by layer by a selective recoater.

[0045] Furthermore, it can be provided, alternatively or additionally, that after the production of at least one component, the component is separated from the support material, in particular removed from the production area freed of support material. With powdered support material, separation can be particularly easy to implement, especially automatically. For example, separation devices are known from powder-based additive manufacturing processes for the automated removal of powdered material from a production area. For example, a manufacturing system implementing the manufacturing process can be extended with a separation device such as those known from a binder jetting process or a powder bed fusion process. AIM128WO Page 12

[0046] Alternatively or additionally, it can be provided that, after the production of at least one component, the support material is reused for the production of another component. In this way, the support material, especially powdered support material, can remain undamaged during the manufacturing process in the proposed solution and is therefore readily available for a subsequent manufacturing process after being removed from the manufactured component.

[0047] The proposed solution further relates to the use of a recoater, in particular a selective recoater, for applying powdered material in a process for the additive manufacturing of at least one component by at least one extrusion device. As already explained above, the proposed solution thus provides in particular for combining a recoater for powder printing with a material extrusion process.

[0048] The attached figures illustrate possible implementation variants of the proposed solution.

[0049] This shows:

[0050] Figure 1A shows a section of a substrate of a proposed

[0051] Manufacturing system in which, in a first step of a manufacturing process, a frame for enclosing a manufacturing area for an additively manufactured component is produced by the extrusion device of the manufacturing system, and, within the manufacturing area, a first component layer for the component is produced;

[0052] Figure 1B shows the manufacturing area filled with powdered support material in the space between the component layer and the frame, in a view corresponding to Figure 1A;

[0053] Figure 1C shows a later stage in the manufacturing process, in which several voids exist within a component layer, which are filled with the powdered support material; AIM128WO page 13

[0054] Figure 1D shows the manufacturing area with a further constructed

[0055] Frame defined box which is filled with the powdered support material in which the component is embedded;

[0056] Figure 1 E the box of Figure 1 D after removal of the powdered

[0057] Support material for exposing the manufactured component;

[0058] Figure 2 shows an embodiment of a proposed manufacturing system for the additive manufacturing of a component according to an embodiment of a proposed manufacturing process, the manufacturing phases of which are illustrated by reference to Figures 1 A to 1 E;

[0059] Figure 3 is a partially cutaway, schematic representation of a

[0060] Extrusion device of the manufacturing system of Figure 2;

[0061] Figure 4 shows a flowchart for a variant of a proposed manufacturing process with selective layer-by-layer filling of voids with powdered support material;

[0062] Figure 5 shows a flowchart for a further embodiment of a proposed manufacturing process in which powdered support material is applied over a surface and then parts of the manufacturing area are selectively freed from the powdered support material, on which component material is to be deposited by means of the extrusion device;

[0063] Figures 6A-6D show different phases of an additive manufacturing process known from the prior art, in which support structures for the component to be manufactured are produced by means of an extrusion device.

[0064] Figure 1A shows a partial perspective top view of a base 11 of a manufacturing system S for the additive manufacturing of a component 1 (see Figures 1E and 2). The base 11 is, for example, formed by a height-adjustable platform on the manufacturing system S. In addition to an extrusion device formed by a screw extruder 2, the manufacturing system S also includes an additional AIM128WO page 14

[0065] Powder application device 5 is used to combine material extrusion pressure, which is implemented with the screw extruder 2, with aspects of powder printing. Instead of a screw extruder 2, another extrusion device, for example a filament extruder, would also be conceivable.

[0066] In a first phase of an embodiment of a proposed manufacturing process, as shown in Figure 1A, a frame for the manufacturing area 9 is produced from a component material, for example a plastic material, in particular a fiber-reinforced plastic material, by forming a first layer 90S of a manufacturing frame R using the screw extruder 2. In the same manufacturing plane (relative to a Cartesian coordinate system, for example in an xy-plane), a first component layer 1S for the component to be manufactured is formed.

[0067] I is generated. The first component layer 1S is then located within the manufacturing area 9, which is completely enclosed here by the first layer 90S of the manufacturing frame R.

[0068] In a subsequent manufacturing step, as shown in Figure 1B, a powdered support material is applied layer by layer via the powder application device 5, for example, a selective recoater such as those distributed by Schaeffler Aerosint SA, Belgium. The powder application device 5 thus produces a powder layer 92P. The thickness of this powder layer 92P corresponds to the thickness of layer 90S for the manufacturing frame R and the component layer 1S, both of which were produced from the molten component material, or it has a smaller thickness, so that the powdered support material remains within the manufacturing frame R.In a selective, layer-by-layer powder application, the surface of component layer 1S is left uncovered and the powdered support material is only selectively applied in the space between the manufacturing frame 90S and component layer 1S.

[0069] If, during the further manufacturing process as shown in Figure 1C, additional free spaces 91.1 to 91.4 arise within the manufacturing area 9 between sections of an applied component layer 1S, these are also selectively filled with powdered support material after the component material has been applied by the screw extruder 2. The powdered support material is used to support, in particular, overhanging sections of the component 1 to be manufactured on the substrate.

[0070] II supported, without the need for the generation of support structures by the screw extruder 2. AIM128WO Page 15

[0071] After completion of the manufacturing process according to Figure 1D, a box is produced on the base 11 using the layer-by-layer manufacturing frame R, inside of which the additively finished component 1 is embedded in powdered support material.

[0072] If the powdered support material, for example glass bead powder, is removed (preferably automatically within the manufacturing system S) – without mechanical or chemical post-treatment processes – the component 1 is available for removal within the manufacturing frame R, as shown in Figure 1 E. The removed powdered support material does not need to be disposed of, but can be used to manufacture another component 1.

[0073] Figure 2 schematically shows a perspective view of a variant of the manufacturing system S with the screw extruder 2 and the powder application device 5. The manufacturing system S is a 3D printing device that combines material extrusion printing by the screw extruder 2 with aspects of powder printing. Using the screw extruder 2, plastic material, in particular fiber-reinforced plastic material, can be used as component material for the additive manufacturing of the component.

[0074] 1. can be used by means of thermoplastic fusion. The screw extruder

[0075] The workpiece 2 is movable above the base 11, on which the component 1 to be manufactured is formed, via a three-axis adjustment device 21. Material strands made of molten plastic material are applied to the base 1 via an extrusion die 10 of the screw extruder 2. The extrusion process is controlled by an electronic control unit 20.

[0076] As illustrated by the enlarged cross-sectional views in Figure 3 for the screw extruder 2, the screw extruder 2 has a conveying screw 3 for conveying powdered or granular plastic material towards the extrusion die 10. This conveying screw 3 extends along a longitudinal axis over a feed zone 31, a subsequent melting and compression zone 32, and up to an discharge zone 33. The conveying screw 3 is rotatably mounted about its longitudinal axis in a housing 4 of the screw extruder 2 and is driven by a motor (not shown). AIM128WO Page 16

[0077] The housing 4, which at least partially accommodates the screw conveyor 3, is shown in the cross-sectional view of Figure 3 with different housing sections 41g, 42g, and 43g. The individual housing sections 41g, 42g, and 43g can also form independent housing parts that are connected to one another and together define the housing 4. A first housing section 41g defines a funnel-shaped inlet for the feed of the powdered or granular plastic material, which, as a composite material, comprises, for example, a thermoplastic matrix material with embedded fibers. Adjoining the first housing section 41g with the inlet, which defines a feed zone 41 for the plastic material, a second housing section 42g forms a thermal barrier zone 42 in the conveying direction towards the extrusion die 10.The barrier zone 42 separates the intake zone 41 from a heating zone 43, which is formed by a subsequent third housing section 43g of the housing 4. For the thermal separation of the intake zone 41 from the heating zone 43, the second housing section 42g is, for example, made of a high-strength but thermally very poorly conductive material, such as a ceramic, and may optionally feature additional intake cooling. For example, the housing section 42g of the thermal barrier zone 42 is made of zirconium oxide or aluminum oxide.

[0078] For the formation of the heating zone 43, the third housing section 43g has one or more heating elements arranged circumferentially. The plastic material conveyed towards the extrusion die 10 is melted by the heating elements 9 so that it can be extruded from the extrusion die 10 in a filament whose thickness is determined by the geometry of the extrusion die 10, which is interchangeably fixed to the housing 4.

[0079] The vertically arranged conveying screw 3, when installed as intended, extends within the housing 4 such that the intake area 31 of the conveying screw 3 is completely enclosed by the first housing section 41g and the intake zone 41 formed therein. The plastic material is compressed by the conveying screw 3 via the compression and melting zone 32 of the conveying screw 3, which adjoins the intake zone 31 within the third housing section 43g and thus within the heating zone 43. For this purpose, the conveying screw 3 is designed as a plug screw, in which the diameter of one shaft of the conveying screw 3 increases conically in the area of ​​the melting and compression zone 32 at an angle of 7° to 10° and up to 1.5 to 2 times the smallest diameter of the conveying screw 3. AIM128WO Page 17

[0080] In an ejection zone 33 of the screw conveyor 3, which adjoins the melting and compression zone 32 and is also located within the heating zone 43, the (larger) diameter of the shaft 6 of the screw conveyor 3 remains constant. A reservoir 7 adjoins the ejection zone 33, and thus an axial end of the screw conveyor 3, in the conveying direction of the plastic material. This reservoir 7 is formed between the axial end of the screw conveyor 3 and the extrusion die 10 and is defined, at least partially, by a conical taper V of the inner, screw conveyor 3-facing surfaces of the third housing section 43g in the heating zone 43. Molten plastic material is held under pressure in this reservoir 7, which has a maximum length of 1 / 15 of the total length of the screw conveyor 3.The internally provided conical taper V in the third housing section 43g in the direction of the extrusion nozzle 10 has an opening angle (p) on the order of 58° or more.

[0081] In the illustrated screw extruder 2, the plastic material is first drawn into the funnel-shaped inlet of the feed screw 3 in the feed area 31 and transported downwards along the conveying direction by the feed screw 3. Due to the thermal barrier zone 42 in the housing 4, the plastic material is free-flowing up to the second housing section 42g, which forms the barrier zone 42. Furthermore, it is ensured that no compression occurs within the housing 4 until the heating zone 43 is reached, due to a change in the pitch of the screw flights or the diameter of the shaft of the feed screw 3.

[0082] Only in the heating zone 43, which directly adjoins the barrier zone 42 below, is the plastic material melted and compressed. For this purpose, radially arranged heating elements are provided on the housing side of heating zone 43. These elements extend over the entire length of heating zone 43 and enable a very localized application of heat energy. The heating zone 43 has a maximum length on the housing side that corresponds to half the length of the screw conveyor 3. The third housing section 43g, which forms heating zone 43, has a higher thermal conductivity than the second housing section 42g, which forms barrier zone 42, and also has a greater thermal mass than this second housing section 42g.

[0083] In the extrusion device shown, in the form of the screw extruder 2, the volume provided in the heating zone 43 for plastic material 8 is located inside the AIM128WO page 18

[0084] Housing 4 to less than 5.5 cm 3 , presently on approximately 3.30 cm 3 , limited. In other words, the maximum volume of the plastic material to be conveyed along the longitudinal axis of the screw conveyor 3 towards the extrusion die 10 in the heating zone 43 is 3.30 cm³. 3 available. This volume is calculated from the difference between the cavity in the third housing section 43g, in which the conveying screw 3 extends with its melting and compression zone 32 and its discharge zone 33, and the volume occupied by the conveying screw 3 itself.

[0085] Furthermore, the electronic control unit 20 limits the maximum speed of the screw conveyor 3 to 30 revolutions per minute around its longitudinal axis. Taking this speed limitation into account, the volumetric conveying rate of the screw conveyor 3 is set such that the plastic material to be conveyed towards the extrusion die 10 remains in the heating zone 43 for a maximum of 20 minutes, here, for example, at least 1.5 seconds, but no more than 20 minutes. This results in a comparatively high discharge rate of up to 7500 cm³ from the screw conveyor 3. 3 per hour, especially 5500 cm 3 per hour, 2500 cm 3 per hour, 1000 cm 3 per hour or 250 cm 3per hour. Combined with a length-to-diameter ratio of less than 10 for the screw conveyor 3, this ensures that the plastic material remains in the heating zone 43 for a comparatively short time, thus preventing degradation of the plastic material. This is further enhanced by the design of the heating zone 43 with a maximum length of 24 mm and a diameter of less than 18 mm. Furthermore, it has been shown that in an extrusion process implemented with the screw extruder 2 according to the aforementioned process parameters, any fibers potentially contained in the powdered or granular plastic material are only sheared off to a comparatively small extent, and approximately 70% of the fibers are deposited in the direction of travel of the extrusion die 10. This allows for influencing the fiber orientation and thus the strength of the component 1 to be manufactured, independent of the component geometry.During a 3D printing process, only the travel path of the extrusion nozzle 10 needs to be manipulated.

[0086] The throughput time in heating zone 43 and along the melting and compression zone 32 of the screw conveyor 3 is fundamentally dependent on the plastic material used. According to the proposed solution, the maximum speed of the screw conveyor 3 is limited to a maximum of 30 revolutions per minute. This results – in combination with the length-to-diameter ratio of the screw conveyor 3 being less than 10 – in low shear forces, and the throughput time is selected such that the residence time of the AIM128WO (page 19) is short.

[0087] The dwell time for the plastic material in the heating zone is a maximum of 20 minutes. This short dwell time, determined in particular by the flow rate, is limited by the specified volume of less than 5.5 cm³. 3Due to the defined small quantity of plastic material in the geometrically comparatively short heating zone 43 (especially in relation to the length of the screw conveyor 3), the plastic material remains in the hot state for only a short time and the melt held in the melting and compression zone 32 has a sufficiently short throughput time.

[0088] The compact screw extruder 2 shown is capable of processing plastic material containing, for example, at least one of the following matrix materials: polyaryletherketone (PAEK), polyetherketone (PEEK), polyetherimide, polycarbonate, polylactate, polyethylene, polyethylene terephthalate, polymethyl methacrylate, polybutylene terephthalate, acrylonitrile butadiene styrene copolymer, polyoxymethylene, polypropylene, polystyrene, polyvinyl chloride, and polyamide. Furthermore, various fillers, such as reinforcing materials in the form of glass fibers, aramid fibers, steel fibers, carbon fibers, synthetic fibers, plastic-based fibers, natural fibers, and / or ceramic fibers, can be embedded in the matrix material. Additional reinforcement can also include powder or fragments of glass or other materials. The plastic can also be mineral-reinforced.

[0089] In the illustrated screw extruder 2, in addition to a granule feeder 2R for granular plastic material, a comminution device 2Z is ​​provided. This comminution device 2Z is, by way of example, located above the feed zone 41 and thus above the funnel-shaped inlet. The comminution device 2Z has at least one comminution tool to comminute a starting material, for example in the form of granules, rods, or fragments of plastic, and to provide a powdered plastic material (in particular, plastic powder with a particle size in the range of 50 pm to 1000 pm).

[0090] The 3D printing device of the manufacturing system S, which includes the screw extruder 2, can thus be fed coarser plastic material via the comminution unit 2Z. This material is processed into a plastic powder by one or more comminution tools of the comminution unit 2Z and subsequently conveyed to the feed screw of the screw extruder 2. AIM128WO Page 20

[0091] Alternatively or additionally, a dosing unit can be integrated into the 2Z shredding unit. In this configuration, the 2Z shredding unit can thus shred, in particular grind, the feed material and then feed it in a metered manner.

[0092] The powder application device 5 of the illustrated manufacturing system S can also be controlled via the electronic control unit 20. The powder application device 5 of the manufacturing system S has an application unit 50 for the powdered support material, which is supplied to the application unit 50 via a support material dispenser 51 – here in the form of a powder reservoir or powder feeder. If a material filament has been applied at the extrusion die 10 in an xy-production plane to apply a production frame layer 90S and a component layer 1S, and thus to further form the component 1 in a vertically extending build direction z, the powder application device 5 can apply powdered support material under the control of the control unit 20.For this purpose, the application unit 50 is moved translationally along the base 1 in the current xy production plane along at least one of opposing adjustment directions L1, L2, whereby the powdered support material is applied across the production area 9 during the adjustment. As illustrated in Figures 1A to 1E, at least one powder layer 92P can be produced in the production area 9 with the powder application device 5. If necessary, and in particular depending on the height of the component layer 1S and / or the particle size of the powdered support material and thus the height of the powder layer 92P, several (at least two) powder layers 92P can also be applied before another component layer 1S is produced.

[0093] In a selective recoater, the powder application device 5 is capable of and designed to deposit powdered support material, at least for overhanging sections of the component 1 to be manufactured, only on those parts within the manufacturing area 9 where no component material has previously been deposited by the screw extruder 2.

[0094] Alternatively, it can also be provided that at least those parts of the production area 9 where component material was previously deposited by the screw extruder 2 are also coated with powder. Here, powdered support material is then removed from these parts of the production area 9 by a scraping device 52 integrated into the powder application device 5. AIM128WO Page 21

[0095] For any surface treatment of the applied powder layer 92P, the manufacturing system S can include a surface treatment device 6. In the embodiment shown in Figure 2, this surface treatment device 6 is provided on the powder application device 5. The surface treatment device 6 can, for example, be used for thermally melting the support material, chemically dissolving the support material, applying an adhesion promoter to the support material, applying a release spray to the support material, and / or activating a coating on the (coated) support material.

[0096] The flowchart in Figure 4 illustrates a previously explained embodiment of a proposed manufacturing process in which cavities in the manufacturing area 9 are selectively filled with support material, in particular powdered support material. In a first step S1, the component layer 1S and the layer 90S for the (manufacturing) frame 9 are produced by extrusion pressure using the screw extruder 2. In a subsequent manufacturing step S2, existing cavities 91.1 to 91.4 within the manufacturing area 9 are selectively filled with at least one new layer of support material. Depending on the thickness of a produced powder layer 92P, particularly in relation to the thickness of a component layer 1S, existing cavities 91.1 to 91.4 within the manufacturing area 9 can optionally be filled multiple times with several powder layers in manufacturing step S2.Following manufacturing step S2, a surface treatment of the support material can be applied in a further step S3. If it is determined in step S4 that the component 1 to be manufactured is complete, the support material is removed in step S5 and component 1 is removed from the substrate 11. Otherwise, a new component layer 1 S is created in a subsequent xy manufacturing level (which is defined, for example, by moving the substrate downwards), and support material is then applied again.

[0097] Instead of a powdered support material, another support material can also be introduced into free spaces within the manufacturing area 9 using a non-extrusion method to support sections, particularly overhanging sections, of the component 1 during the manufacturing process. For example, the introduction of viscoelastic support material after the production of one or more component layers 1 can be provided within the manufacturing system S using an adjustable application device analogous to the powder application device 5 of Figure 2. When using a viscoelastic support material, for example, leveling a layer of support material applied (see AIM128WO page 22) is not necessary from the outset, since viscoelastic material distributes itself evenly upon application without any further mechanical influence.Furthermore, viscoelastic support material, which may adhere to the substrate 1 or the finished component 1, can regularly be easily peeled off the substrate 11 and / or the component 1 without mechanical or chemical post-treatment processes. A viscosity range of a viscoelastic support material is, for example, in the range of 5 mPa*s to 10,000,000 mPa*s, particularly in the range of 10 mPa*s to 1,500 mPa*s.

[0098] Alternatively, the application of a support material containing at least one photopolymer can be used. A photopolymer-based support material is typically more fluid than a viscoelastic support material and can therefore be dosed more precisely. Furthermore, a photopolymer-based support material allows for better contour definition of the support structure formed with it. Another advantage is that the hardness, and thus the strength, of a support structure formed with a photopolymer-based support material can be adjusted (by varying the exposure method).

[0099] In an alternative embodiment according to the flowchart of Figure 5, after the production of a component layer 1S and a layer 90S for the (production) frame R by the screw extruder 2 in manufacturing step S2a, powdered support material is applied over the entire surface of the production area 9 without extrusion. Subsequently, in a following manufacturing step S2b, support material is selectively removed using the scraping device 52. Areas are freed of support material where another component layer 1S is to be applied.

[0100] A dispensing device of a manufacturing system S can also be set up and designed to dispense a material different from the support material into a free space 91.2 to 91.4 present in the manufacturing area 9, in order to specify certain physical properties of the component 1 to be manufactured. The additional material to be applied via the dispensing device 5 can, for example, serve to selectively influence, at least locally, the density, rotational stiffness, thermal conductivity and / or damping of the component 1 to be manufactured.

[0101] Alternatively or additionally, support material may be provided for at least partially remaining on the finished component 1, or for at least partially remaining on the component 1 (i.e., as part of the component 1), in order to predefine certain physical properties of the component 1, for example, to influence its density, rotational stiffness, thermal conductivity, and / or damping at least locally (see AIM128WO, page 23). For example, one embodiment may provide that a free space 91.2, 91.4 on the finished component 1 forms part of an internal and, if necessary, completely closed cavity. Support material can be introduced into this cavity during the additive manufacturing process and remains at least partially enclosed within the cavity of the finished component 1.The support material remaining in the cavity can, for example, form a balancing mass within component 1. This includes, in particular, a design variant in which, during or at the end of the additive manufacturing process, at least part of the support material is removed from a partially or completely closed cavity of component 1 (for example, by creating an opening to the cavity during the additive manufacturing process or by subsequently creating one, e.g., through drilling, and by draining at least part of a powdered support material from the cavity), and thus ultimately a part of the originally applied support material remains within component 1 to influence its physical properties.

[0102] With a manufacturing system S of Figures 2A and 3, and the embodiment variants of a proposed manufacturing process illustrated in Figures 4 and 5, manufacturing times for the additive manufacturing of a component 1 can be significantly reduced compared to a conventional approach, as illustrated in Figures 6A to 6D, in which support structures 99 are always formed via the screw extruder 2. It has been shown that, compared to the process according to Figures 6A to 6D, the total printing time can be significantly reduced, in some cases by more than 20% or more than 30%. The removal of the support material is also considerably simplified, especially when powdered support material is applied via a selective recoater.The aforementioned advantages are accompanied by significant cost savings, while the use of screw extruder 2 allows for a high degree of design freedom in the manufactured component. Due to the material extrusion through screw extruder 2, there are virtually no restrictions on the component material that can be used. In particular, the use of plastic material is clearly not mandatory, and component materials based on metal and / or ceramic can also be used. AIM128WO Page 24.

[0103] Reference symbol list

[0104] 1 component

[0105] 10 Extrusion die

[0106] 11 Document

[0107] 1S component layer

[0108] 2 screw extruders (extrusion device)

[0109] 20 Control unit

[0110] 21 Adjustment device

[0111] 2R Granule Feed

[0112] 2Z shredding unit

[0113] 3 Conveyor screw / extruder screw

[0114] 31 catchment area

[0115] 32 Melting and compression zone

[0116] 33 Ejection zone

[0117] 4 cases

[0118] 41 catchment area

[0119] 41g, 42g, 43g housing section

[0120] 42 (thermal) barrier zone

[0121] 43 heating zones

[0122] 5 Powder application device (dispensing device)

[0123] 50 application units

[0124] 51 Powder reservoir / powder feed (support material dispenser)

[0125] 52 Smear device

[0126] 6 Surface Treatment

[0127] 7 Reservoir

[0128] 9 Production area

[0129] 90S manufacturing frame layer

[0130] 91.1, 91.2, 91.3, 91.4 Free space

[0131] 92P powder coating

[0132] 99 Support structure

[0133] L1, L2 Adjustment direction

[0134] R manufacturing framework

[0135] S manufacturing system

[0136] V tapering P opening angle

Claims

AIM128WO Page 25 Claims 1. Manufacturing system for the additive manufacturing of at least one component (1), wherein the manufacturing system (S) comprises at least one extrusion device (2) with which component material for the production of the at least one component (1) can be applied in successive component layers (1S) along at least one build direction (z) in a manufacturing area (9), characterized in that the manufacturing system (S) comprises, in addition to the at least one extrusion device (2), at least one dispensing device (5) with which, after the application of at least one component layer (1S), a free space (91.1, 91.2, 91.3, 91.4) existing in the manufacturing area (9) can be at least partially filled without component material with at least one support material.

2. Manufacturing system according to claim 1, characterized in that the at least one dispensing device (5) is configured to produce at least one layer (91P) with support material in at least one existing free space (91.1, 91.2, 91.3, 91.4).

3. Manufacturing system according to claim 1 or 2, characterized in that the manufacturing system is equipped with the at least one extrusion device (2) and the at least one dispensing device (5) to apply component material for the component to be manufactured (1) layer by layer and support material layer by layer in at least one free space (91.1 , 91.2 , 91.3 , 91.4) in the manufacturing area (9) in successive manufacturing levels (xy-levels) along the build direction (z).

4. Manufacturing system according to one of claims 1 to 3, characterized in that the at least one dispensing device (5) is set up and provided for a non-extrusion-based application of support material.

5. Manufacturing system according to one of the preceding claims, characterized in that the at least one dispensing device (5) is set up and provided for applying powdered support material. AIM128WO Page 26 6. Manufacturing system according to claim 5, characterized in that the at least one dispensing device (5) is set up and provided for the selective and layer-by-layer application of powdered support material into at least one free space (91.1 , 91.2, 91.3, 91.4).

7. Manufacturing system according to claim 5, characterized in that the at least one dispensing device (5) is set up and provided for the layer-by-layer application of powdered support material in the manufacturing area (9) and comprises a scraping device (52) which is provided to remove at least a part of the manufacturing area (9) of powdered support material after its application.

8. Manufacturing system according to one of claims 1 to 4, characterized in that the at least one dispensing device (5) is set up and provided for applying viscoelastic support material and / or for applying support material containing at least one photopolymer.

9. Manufacturing system according to one of the preceding claims, characterized in that the at least one dispensing device (5) is set up and provided for specifying certain physical properties on the component (1) to be manufactured, and is designed to dispense a material different from the support material into a free space (91.1 - 91.4) present on the manufacturing area (9).

10. Manufacturing system according to one of the preceding claims, characterized in that the manufacturing system (S) comprises a surface handler (6) which is set up and provided for surface treatment of support material applied in the manufacturing area (9).

1. Manufacturing system according to claim 10, characterized in that the surface treater (6) for - a thermal melting of support material, - a chemical dissolving of support material, - the application of an adhesion promoter to support material, - the application of a release spray to support material or - the activation of a coating of the support material is provided.

12. Manufacturing system according to one of the preceding claims, characterized in that the extrusion device (2) is set up and provided, AIM128WO page 27 at least one boundary of the manufacturing area (9) during a manufacturing process for the at least one additive component (1) to be formed from component material.

13. Manufacturing system according to claim 12, characterized in that the extrusion device (2) is set up and provided to produce the boundary of the manufacturing area (9) layer by layer along the build direction (z).

14. Manufacturing system according to claim 12 or 13, characterized in that the extrusion device (2) is set up and designed to form a circumferentially closed boundary of the manufacturing area (9) by means of a closed frame made of component material.

15. Method for the additive manufacturing of at least one component (1), wherein at least one extrusion device (2) is used for the additive manufacturing, with which component material for the production of the at least one component (1) is applied in successive component layers (1S) along at least one build direction (z) in a manufacturing area (9), characterized in that after the application of at least one component layer (1S), at least one free space (91.1, 91.2, 91.3, 91.4) in the manufacturing area (9) is at least partially filled without component material with at least one support material, by means of which at least one section of the component (1) is supported during the further manufacturing process.

16. Method according to claim 15, characterized in that after the manufacture of the at least one component (1 ), the component (1 ) is separated from the support material, in particular removed from the manufacturing area (9) freed from the support material.

17. Method according to claim 15 or 16, characterized in that after the manufacture of at least one component (1 ), the support material is reused for the manufacture of at least one further component. AIM128WO Page 28 18. Method according to one of claims 15 to 17, characterized in that a layer (91 P) with support material is produced in the at least one existing free space (91.1 , 91.2, 91.3, 91.4).

19. Method according to one of claims 15 to 18, characterized in that component material for the component to be manufactured (1) and support material are applied layer by layer in at least one free space (91.1 , 91.2 , 91.3 , 91.4) in the manufacturing area (9) in successive manufacturing levels (xy-levels) along the build-up direction (z).

20. Method according to one of claims 15 to 19, characterized in that the support material is in powder form.

21. Method according to claim 20, characterized in that the powdered support material is applied selectively and layer by layer in at least one free space (91.1 , 91.2, 91 .3, 91 .4).

22. Method according to claim 20, characterized in that the powdered support material is applied layer by layer in the manufacturing area (9) and subsequently at least a part of the manufacturing area (9) is again freed from powdered support material.

23. Method according to one of claims 15 to 19, characterized in that the support material is viscoelastic and / or contains at least a photopolymer.

24. Method according to one of claims 15 to 23, characterized in that the support material applied in the manufacturing area (9) is subjected to a surface treatment.

25. Method according to claim 24, characterized in that - a thermal melting of support material, - a chemical dissolving of support material, - the application of an adhesion promoter to support material, - the application of a release spray to support material or - the activation of a coating of the support material is provided.

26. Method according to one of claims 15 to 25, characterized in that at least one boundary of the manufacturing area (9) during the AIM128WO Page 29 manufacturing process for which at least one additive component (1) is formed from component material.

27. Method according to claim 26, characterized in that the boundary of the manufacturing area (9) is produced layer by layer along the build direction (z).

28. Method according to claim 26 or 27, characterized in that a circumferentially closed boundary of the manufacturing area (9) is formed by a closed frame made of component material.

29. Use of a recoater for applying powdered material in a process for the additive manufacturing of at least one component by at least one extrusion device (2).

Images