METHOD FOR PRODUCING A MOLDED COMPONENT, AND MOLDED COMPONENT PRODUCED BY SUCH A METHOD

Description

State of the art

[0001] The invention relates to a method for producing a molded component according to the preamble of claim 1. Furthermore, the invention relates to a molded component produced by such a method.

[0002] D1 WO 2015 / 139095 A1 discloses a method and a device for producing a composite object from a first and a second material.

[0003] D3 CN 106 891 524 describes a 3D printing process and a device for the targeted joining of short fibers in a liquid matrix.

[0004] D7 US 9 457 521 B2 describes a method, apparatus and material mixture for the direct digital fabrication of fiber reinforced parts.

[0005] In a known, generic 3D printing process, a component is produced by layering a starting material in a sequence during the printing process. All layers then form the component. This is achieved by using starting materials that are in a liquid or at least viscous state at the printing temperature during printing and then cool to ambient temperature after the layer is formed.

[0006] The starting materials change their state of matter and harden. This allows for the layer-by-layer production of a molded component. A disadvantage of such molded components is that their mechanical properties, such as the strength of the manufactured component, can only be influenced by the choice of starting material. In standard 3D printing processes, thermoplastic materials such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), acrylates, epoxies, or polyurethanes are typically used as starting materials. However, the thermal requirements of the printing process significantly limit the material selection, which is why starting materials that exhibit high strength in their cured state are very rare. Disclosure of the invention

[0007] The inventive method for producing a molded component with the features of claim 1 has the advantage that the strength of the molded component is particularly high. In particular, this enables the production of molded components with intricate structures using a classic 3D printing process, whereby the molded component nevertheless possesses high strength and, in particular, good mechanical load-bearing capacity.

[0008] The manufacturing process according to the invention comprises at least one further layer, which is produced, at least in certain areas, by a spraying process using fiber fragments. The fiber fragments improve the mechanical properties of the molded component. This is achieved because the forces acting on the molded component can be absorbed more effectively by the individual fiber fragments contained in the further layer. Preferably, a further layer produced by the spraying process is provided in the molded component. However, several layers, each containing a plurality of fiber fragments and produced by the spraying process, can also be formed in the molded component, which together then ensure improved mechanical strength of the molded component.Alternatively, particularly with a 3D printing process based on so-called Multi Jet Modeling (MJM) technology, it is also possible to introduce the additional layer into an outer layer. According to the invention, this allows the advantages of the classic 3D printing process to be utilized and molded components, especially prototypes, to be produced in a short time. The mechanical properties can be improved by introducing at least one additional layer into the multi-layered molded component using a spraying process, and in particular, the strength of the molded component under mechanical stress can be enhanced.

[0009] The additional layer created by the spraying process contains fiber fragments made of glass or aramid, approximately 50 mm in length. This allows for the formation of further layers within the molded component, which only marginally increase the component's weight (mass) while significantly improving its mechanical properties, particularly its strength. Besides the short production times resulting from the 3D printing process, this also allows for a considerable reduction in manufacturing costs compared to components made entirely of carbon fiber.

[0010] Advantageous further developments of the manufacturing process according to the invention are listed in the dependent claims.

[0011] In a further development of the invention, the fiber pieces contained in the subsequent layer are arranged in an oriented manner. In other words, this means that all fiber pieces in a layer produced by the spraying process are arranged in an ordered manner, with the longitudinal directions of the fiber pieces preferably being parallel and / or nearly parallel to each other. This makes it possible to increase the strength of the molded component compared to an anisotropic, i.e., disordered, arrangement of the fiber pieces in the at least one subsequent layer. This is preferably achieved by applying the fiber pieces to the molded component in the spraying process through a nozzle for forming the subsequent layer in such a way that all fiber pieces have the same orientation. Alternatively, however, an anisotropic, i.e., arbitrary, arrangement of the fiber pieces in the subsequent layer is also possible.This allows the mechanical properties of the molded component, especially its mechanical strength, to be specifically tailored to the application. Furthermore, it is also possible for the molded component to comprise several additional layers produced by spraying, with the fibers in all these additional layers being arranged in different directions, i.e., anisotropically.

[0012] The further development involves incorporating a binder for the fibers into the subsequent layer during the spraying process. This improves the mechanical properties of the subsequent layer, as the binder makes the layer containing the fibers significantly more robust. This results in greater stability of the molded component or the subsequent layer containing the fibers under direct stress. The binder also preferably increases the strength of the subsequent layer at high temperatures or in aggressive environments, such as salty sea air. Furthermore, the direct incorporation of the binder via spraying eliminates an additional process step in which such a binder is applied to the fibers. The binders are preferably formed using hardening synthetic resins, such as epoxy resins and / or reactive resins.To cure the synthetic resins, a thermal treatment of the subsequent layer (tempering) can be provided. Alternatively, irradiation of the layer with UV radiation is also possible, which leads to the curing of the binder. Additionally, the binder can also contain microballoons as a filler, which can then also lead to an improvement in the mechanical properties or a reduction in weight. Furthermore, it is also preferred if, in a final process step, all layers are thermally treated together for curing after the application of the subsequent layer.

[0013] A preferred embodiment of the manufacturing process according to the invention provides that the fiber pieces partially overlap, thereby increasing the mechanical properties and, in particular, the strength of the molded component. To form the further layer, the fiber pieces are sprayed on in such a way that partial areas of the fiber pieces overlap, which are then firmly bonded and fixed together by the binders.

[0014] The further development involves the mold components having outer layers that are produced exclusively using a printing process. This enables the production of mold components with intricate outer structures, which nevertheless possess improved mechanical properties due to the arrangement of an additional layer containing fiber fragments in the inner area. Thus, all components produced using conventional 3D printing methods can also be manufactured using the inventive method. Advantageously, in the inventive manufacturing process, the mechanical properties of the entire mold component can be specifically improved and / or adapted by arranging the additional layer containing fiber fragments in the inner area.

[0015] In a further development of this invention, the molded component comprises at least two additional layers, which are produced at least partially by spraying. This makes it possible to improve the mechanical properties, in particular the strength, by means of at least two additional layers, each containing at least two fibers. The mechanical properties, especially the strength, can be further increased by at least two additional layers compared to just one additional layer. Preferably, it is also possible to orient the fibers differently in the two additional layers, thereby enabling the mechanical properties of the molded component to be specifically adapted with respect to direction-dependent forces.

[0016] Further development also envisages the placement of two additional layers of the molded component, produced using the spraying process, directly on top of each other. This allows for influencing the thickness of these additional layers, and, depending on the application, also the mechanical properties of the molded component.

[0017] Alternatively, it is also possible to further develop the mold by arranging at least two additional layers within the molded component, with at least one layer produced by a printing process positioned between these two additional layers. Depending on the application, this also allows for a targeted improvement of the molded component's mechanical properties and thus application-specific customization.

[0018] Furthermore, a further development of the invention reveals a process step in which the at least one additional layer produced by spraying is subjected to a post-treatment, particularly a thermal one, to increase its strength. This can involve a purely thermal treatment, in which the additional layer comprising the molded component or the fiber pieces is brought to a specific temperature, thereby activating a curing process, particularly due to the binder. Alternatively and / or additionally, curing can also be achieved by irradiating the molded component and / or the additional layer comprising the fiber pieces, preferably using UV radiation.

[0019] Finally, the invention also includes a molded component manufactured according to a method according to the invention, wherein the molded component is a housing part that is used particularly in the automotive sector.

[0020] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

[0021] This shows in: Fig. 1 a side view of a schematically shown molded component, which was manufactured using a 3D printing process and has a further layer comprising fiber pieces produced using a spraying process, Fig. 2 a view through the Fig. 1 known molded component in direction II-II of the Fig. 1 , as well as in Fig. 3 a schematic representation of a further layer containing fiber pieces, which was produced using the spraying method.

[0022] In the figures, functionally identical or equivalent elements and assemblies are marked with the same reference symbols.

[0023] The Fig. 1 Figure 1 shows a side view of a schematically depicted mold component 1, which was produced from a starting material 9 using a 3D printing process according to the invention. The starting material 9 is a thermoplastic polymer, such as ABS, PLA, polyurethane, epoxy, acrylate, polycarbonate, or Ultem. The mold component 1 has a cylindrical outer contour 2 with a circular base 3 and a corresponding lateral surface 4. All outer surfaces of the mold component 1 were produced using a conventional 3D printing process. For this purpose, a geometric model of the mold component 1 is first created, from which individual layers 5 are then determined that can be produced from the starting material 9 using the 3D printing process. During the 3D printing process, the starting material 9 is first heated to a temperature at which its state of matter is liquid, in particular viscous.The printing process then takes place, in which the preheated starting material 9 is printed, thus forming a layer 5. Since the temperature of the starting material 9 drops to ambient temperature after printing, the starting material 9 hardens. This enables the layer-by-layer formation of the molded component 1.

[0024] To increase the strength of the molded component 1, a further layer 7 is produced in the molded component 1 by a spraying process, according to the invention. Fig. 1 Fiber pieces 6 (not shown in detail) are arranged in the further layer 7 such that all fiber pieces 6 in the further layer 7 are aligned in the same direction and partially overlap each other. During the spraying process, a binder 8 is also sprayed on, which ensures that the fiber pieces 6 are held or fixed in the sprayed, aligned position. The further layer 7, provided in the interior of the molded component 1 and produced by the spraying process, significantly increases the mechanical properties of the molded component 1, resulting in the molded component 1 possessing higher strength.

[0025] Fig. 2 shows a view through the Fig. 1 known molded component 1, wherein the additional layer 7 produced in the molded component 1 by the spraying process is now visible. The additional layer 7 is formed outside the area of ​​the fiber pieces 6 by the starting material 9, which was produced by the conventional 3D printing process. This makes it possible to construct molded components 1 by the manufacturing process according to the invention, whose outer contour 2 is homogeneously formed by the starting material 9, wherein the molded components 1 have improved mechanical properties due to the provision of the additional layer 7 in the inner area, and wherein, in particular, the stiffness is increased by the non-in Fig. 2 The fiber pieces 6, shown in detail and fixed together by the binding agent 8, are improved in the further layer 7. This allows all mold components 1 that can be produced by means of 3D printing to be manufactured, which, according to the invention, have improved mechanical properties due to the at least one further layer 7 compared to mold components produced solely by 3D printing.

[0026] Fig. 3 Figure 1 shows a schematic representation of the additional layer 7 produced by the spraying process. The individual fiber pieces 6 are visible in this representation, with all fiber pieces 6 being aligned in an ordered relative arrangement and fixed in this ordered relative arrangement by the binder 8 covering or impregnating the fiber pieces 6. The fiber pieces 6 have a length of approximately 50 mm and consist of aramid 11, which results in a particularly high strength of the molded component 1.

[0027] It is further explained that, in addition to the embodiments shown, the molded component having at least one further layer can be formed not only by a 3D printing process based on fused deposition modeling, but also by another 3D printing process, such as stereolithography (SLA) technology, selective laser sintering (SLS) or multi jet modeling (MJM).

Claims

1. Method for producing a shaped component (1), wherein the shaped component (1) is produced from multiple layers (5, 7) arranged one on top of the other, and wherein at least one layer (5) is produced at least in some regions from a starting material (9) by means of a printing process, characterized in that at least one further layer (7) is produced at least in some regions by means of a spraying process using fibre pieces (6), wherein fibre pieces (6) of glass or aramid (11) with a length of approximately 50 mm are used in the spraying process.

2. Method according to Claim 1, characterized in that in the spraying process the fibre pieces (6) are arranged in an oriented manner.

3. Method according to Claim 1 or 2, characterized in that in the spraying process binders (8) for the fibre pieces (6) are introduced at the same time as the fibre pieces (6).

4. Method according to Claims 1 to 3, characterized in that the fibre pieces (6) are introduced partially one over the other.

5. Method according to Claims 1 to 4, characterized in that the shaped components (1) have outer layers (12) that are created exclusively by means of the printing process.

6. Method according to Claims 1 to 5, characterized in that the moulded component (1) incorporates at least two further layers (7) that are created at least in some regions by means of the spraying process.

7. Method according to Claim 6, characterized in that the at least two further layers (7) are arranged directly one on top of the other.

8. Method according to Claim 6, characterized in that the at least two further layers (7) are arranged such that they are separated by at least one layer (5) created by means of the printing process.

9. Method according to Claims 1 to 8, characterized in that the further layer (7) created by means of the spraying process is subjected to a subsequent treatment, in particular thermal treatment, to increase the strength.

10. Shaped component (1), produced according to one of Claims 1-9, wherein the shaped component (1) is a housing part (13), in particular for automotive applications.