Methods for producing components and the components themselves

Abstract

The invention relates to a method for producing a component (10, 110, 210) by an additive manufacturing method, comprising at least the following steps: - a production plan for the component (10, 110, 210) is generated from digital data, - the component (10, 110, 210) is analyzed with respect to its structure and / or its production parameters with respect to the temperature within the component (10, 110, 210) during production, and - supplementary structures (12, 112, 212) are added to the component (10, 110, 210) where the analysis reveals that the structure and / or the production parameters will result in a non-uniform temperature distribution during production. The invention further relates to a component produced by an additive manufacturing method.

Description

[Technical field]

[0001] The present invention relates to a method for producing a component by additive manufacturing methods as well as to a component produced by additive manufacturing methods. In particular, the component may be a component of a medical product or the medical product itself. [Background technology]

[0002] Additive or versatile manufacturing methods (also known as 3D printing) have become increasingly important over the past decades due to technological advances and will continue to become more and more important in the future.

[0003] In the context of 3D printing of materials in general, and of plastics in particular, for example for medical applications (e.g. for implants), the currently achievable component qualities (warpage, tolerances, strength, toughness, etc.) as well as specific component properties (such as microstructure or surface properties) are increasingly becoming the subject of much scientific investigation.

[0004] 3D printing processes are already known from the prior art as well in connection with medical products, in particular implants.

[0005] For example, a 3D printing device, in particular an FFF printing device, with at least one print head unit is already known from DE 10 2015 111 504 A1, in which the print head unit is provided in at least one operating state for melting a printing material which is at least partially formed by a high-performance plastic, in particular a high-performance thermoplastic material.

[0006] Furthermore, in EP 3 173 233 A1 a three-dimensional manufacturing apparatus is disclosed, which comprises a process chamber which is heated by a process chamber heating unit provided for this purpose.

[0007] Furthermore, US Pat. No. 6,722,872 discloses a three-dimensional modeling apparatus provided for building three-dimensional objects in a heated build chamber.

[0008] Furthermore, US Patent Application Publication No. 2015 / 110911 shows, for example, an environmental monitoring or control unit that is used as an interface of the additive manufacturing technology to its respective environment.

[0009] In fact, WO 2016 / 063198 A1 discloses a method and an apparatus for producing three-dimensional objects by "Fused Deposition Modeling", the production apparatus comprising a radiant heating element capable of heating a surface of the object to be produced that is exposed to the radiant heating element.

[0010] From WO 2017 / 108477 a method for producing a three-dimensional object using a "fused deposition modeling" printer can further be gleaned. Summary of the Invention

[0011] It is an object of the present invention to further develop a method for producing a component by an additive manufacturing method as well as a component produced by said additive manufacturing method, in order that in an advantageous manner, in particular the manufacturing accuracy and dimensional accuracy of the component can be improved.

[0012] This object is achieved according to the invention by a method for producing a component by an additive manufacturing method having the features of claim 1. According to this, a method for producing a component by an additive manufacturing method comprises at least the following steps: - a production plan for the component is generated from the digital data; - the component is analyzed with respect to its structure and / or its production parameters with respect to the temperature within the component during production, and - supplemental structures are added to the component where the analysis reveals that the structure and / or production parameters will result in a non-uniform temperature distribution during production; This includes:

[0013] The invention is based on the fundamental idea of ​​improving the temperature management of a component and therefore the process stability in its additive manufacturing.

[0014] The individualized supplementary structures can be used to manufacture components with improved mechanical properties and at the same time optimized surface quality. When generating functional supplementary structures, the cross-sectional area and / or process parameters of the component geometry are used to design the supplementary structures so that the additive manufacturing process is adapted in the individual layers, and thus the temperature distribution within the component can be influenced during the manufacturing process. Furthermore, the supplementary structures can be used to influence the additive manufacturing manufacturing process (e.g. optimization of the volume flow rate by keeping the extrusion speed as constant as possible during additive manufacturing). This can be advantageously used, for example, in the printing of high-performance plastics (used, for example, in medical technology (implants, devices), aerospace, automotive, ...), and here especially when printing semi-crystalline plastic variants as well. In comparison with conventional support structures, the focus of the described functional supplementary structures is not on the purely geometrical stabilization of the component during the printing process, but on the temperature management of the component and thus on the process stability of the additive manufacturing process.

[0015] In particular, the additive manufacturing method may be a Fused Deposition Modeling (FDM) method or a Fused Layer Modeling (FLM) method or a Fused Filament Fabrication (FFF) method. These methods make it possible to reliably produce components, in particular components for medical applications. The starting point may be, for example, an STL / STEP / OBJ / general CAD file. Said file is first oriented in a process optimization method. Taking into account the geometry and the process-related boundary conditions (cross-sectional area, overhangs, number of builds per layer, materials, process parameters, etc.), the component is aligned with respect to the build platform or print direction. The component can then be analyzed with respect to its cross-sectional area parallel to the build platform and / or with respect to the printing process parameters. According to this analysis, functional complementary structures are generated that significantly improve the temperature management during the printing process.

[0016] One aim of the functional complement structure design process can be to "homogenize" the temperature throughout the component, for example to achieve improved mechanical properties or reduced warpage in the component.

[0017] The replenishment structure also makes it possible to additively manufacture components with a filament emission (volume flow rate) that is as constant as possible, which has a very beneficial effect on the melt formation at the nozzle, especially in extrusion processes such as the FLM / FFF method.

[0018] Goals of the design process for functional supplemental structures can also include, for example, cross-sectional tailoring of mechanical properties within a component (e.g., through different crystallization rates in the case of semi-crystalline polymers), creating hot spots within a component (e.g., to activate additives within a material), or avoiding heat buildup within a component (e.g., to prevent overheating of a heat-sensitive additive within a material (e.g., a pharmaceutical admixture)).

[0019] It is further contemplated that the complementary structures may be generated by modification of the original component geometry.

[0020] It is also conceivable that the complementary structure is generated by addition of at least one separate geometric body.

[0021] Complementary structures can be realized by modification of the original component geometry or by the generation of further separate geometric bodies. Functional complementary structures can be realized as thin-walled (e.g., connecting separated cross-sectional areas to create a consistent cross-sectional area) like scaffold or framework structures, porous structures, etc., and can take over / integrate the functions of traditional support structures (support of undercut geometries, component stabilization, bed adhesion, ...).

[0022] It is also possible for the supplementary structures to be made of a material different from that of the components, which can be done, for example, by 2K printing or 3K printing.

[0023] It is also possible to create a predetermined break point between the component and the replacement structure. Easy removal of the replacement structure is another design goal, which may be achieved by integrating a target predetermined break point or by integrating a structure that is easy to remove (e.g., a porous structure).

[0024] The material of the components may be or include a semi-crystalline polymer, for example, PEEK (polyetheretherketone) may be used.

[0025] In particular, it is conceivable to use medically compatible plastics and / or at least one plastic that can be resorbed by the human or animal body. These materials are of interest for a large number of applications for implants, so that their use in the context of the present invention is particularly advantageous. In addition to the above-mentioned material PEEK, medically compatible plastics can include or be, for example, PEKK (polyetherketoneketone), PAEK (polyaryletherketone), PEI (polyetherimide), or PPSU (polyphenylsulfone), while plastics that can be resorbed by the human or animal body can include, for example, PCL (polycaprolactone), PDO (poly-p-dioxanone), PLLA (poly-L-lactide), PDLA (poly-D-lactide), PGA (poly glycolic acid), or PGLA (polylactide-co-glycolide).

[0026] Similarly, the supplementary structures may be used as reinforcing and / or stabilizing structures for the cooling process of the component. Furthermore, the supplementary structures may be used as mechanical stiffeners of the manufactured component to prevent / minimize distortion in the component. During the production of the component, large temperature gradients in the component occur in the cooling process of the plastic melt, resulting in non-uniform shrinkage of the component (especially when cooling from the melting temperature of the material to the glass transition temperature). Depending on the geometry and the manufacturing process, this may lead to distortion of the component. This distortion can be prevented / minimized by specially arranged stiffening structures. In particular, the supplementary structures may be designed such that the shrinkage of the material in the supplementary structures compensates for the shrinkage of the material in the component, thus minimizing distortion of the component.

[0027] It is further contemplated that at least the addition of the refill structures may occur semi-automatically or automatically.

[0028] Furthermore, the invention relates to a component, according to which the component is produced by an additive production method, in particular by the production method described above, the component comprising at least one supplementary structure.

[0029] In particular, the component may be a component of a medical device or the medical device itself.

[0030] Further details and advantages of the invention will now be explained on the basis of exemplary embodiments shown in more detail in the drawings. [Brief description of the drawings]

[0031] [Figure 1] 4 is a schematic representation of fill structures produced in an exemplary embodiment of a method according to the invention for a component according to the invention, the fill structures serving to unify the cross-sectional area per layer; [Diagram 2]13A-13C are schematic diagrams of refill structures for coarse adjustment of the cross-sectional area per layer and singulation of printheads within a layer for a further exemplary embodiment of the method according to the invention for a component according to the invention; [Diagram 3] 1 shows an exemplary embodiment of a component according to the invention in the form of a cranial implant having a functional supplementary structure according to an exemplary embodiment of a method according to the invention, compared to an implant according to a previous standard. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] FIG. 1 is a schematic diagram of an exemplary embodiment of a component 10 in accordance with the present invention.

[0033] The component 10 now comprises a replenishment structure 12. The replenishment structure 12 is produced by an exemplary embodiment of a method according to the present invention.

[0034] Here, the fill structures 12 serve to unify the cross-sectional area per layer, as will be explained below.

[0035] In this example, the component 10 has the shape of a cone. If the component 10 were built in a classical way, i.e. layer by layer, there would be a risk that problems with faster cooling and dimensional accuracy could arise during production, especially in the area of ​​the cross-sectional plane S2, which has a cross-sectional area significantly smaller than that of the area S1.

[0036] This is prevented by the addition of the refill structure 12.

[0037] In the cross-sectional plane S1, A1_s denotes the cross-sectional area of ​​the filling structure 12 in the area S1, and A1_p denotes the cross-sectional area of ​​the actual component 10.

[0038] In the cross-sectional plane S2, A2_s denotes the cross-sectional area of ​​the filling structure 12 in the area S2, and A2_p denotes the cross-sectional area of ​​the actual component 10.

[0039] Due to the refill structure 12, the cumulative cross-sectional area of ​​the refill structure 12 and the component 10 is nearly identical or the same when the component 10 is manufactured, which means that the temperature distribution and also the cooling behavior are essentially the same.

[0040] 2 illustrates a similar component 110 that is also an exemplary embodiment of the present invention. In FIG. 2, comparable or identical features are marked with the same reference number or with a reference number increased by the value 100.

[0041] 3 shows on the left an exemplary embodiment of a component 210 according to the invention in the form of a cranial implant including a functional supplementary structure according to an exemplary embodiment of a method according to the invention, in comparison to an implant 310 according to past standards in additive manufacturing methods, shown on the right of FIG.

[0042] The component 210 comprises and is connected to the supplementary structures 212 as well. These are commonly produced on a substrate 214 during an additive manufacturing process. Here, the supplementary structures 212 ensure that the component 210 is connected to the supplementary structures 212 at all edges. This ensures that the component 210 has a uniform temperature distribution during manufacturing and also during the cooling process.

[0043] In contrast, the refill structure 312 is missing on the component 310, especially in the upper portion, i.e., the portion facing away from the substrate 314. Now, especially during the cooling phase, the component 310 will cool faster in the area facing the substrate 314. The support structure 312 further amplifies this effect and any temperature gradients, so that without countermeasures such as further tempering, warping of the first cooling structure of the component may occur compared to a slow-cooling structure.

[0044] The method of production of component 10 or 110 or 210 can be described substantially as follows:

[0045] The method for producing the component 10, 110, 210 by additive manufacturing comprises at least the following steps: - a production plan for the component (10, 110, 210) is generated from the digital data; - the component (10, 110, 210) is analyzed with respect to its structure and / or its production parameters with respect to the temperature within the component (10, 110, 210) during production, and - supplemental structures (12, 112, 212) are added to the component (10, 110, 210) where the analysis reveals that the structure and / or production parameters will result in a non-uniform temperature distribution during production. Includes.

[0046] The production method can be the Fused Deposition Modeling (FDM) method or the Fused Layer Modeling (FLM) method or the Fused Filament Fabrication (FFF) method.

[0047] The fill structures 12, 112, 212 may be generated by modification of the original component geometry.

[0048] However, it is also possible that the complementary structure is generated by the addition of at least one separate geometric body.

[0049] The supplemental structures may be formed from a material different from that of the components.

[0050] Additionally, a predetermined break point may be created between the component and the refill structure.

[0051] The material of the components 10, 110, 210 may be or include a semi-crystalline polymer. In the exemplary embodiment shown in Figures 1 to 3, said material is PEEK.

[0052] The supplemental structures 12, 112, 212 serve as strengthening and / or stabilizing structures for the cooling process of the component.

[0053] The addition of the refill structures 12, 112, 212 may be done semi-automatically or automatically.

[0054] The advantages of the method and the components 10, 110, 210 obtained by the method can be explained as follows:

[0055] An advantage, particularly in FLM / FFF methods (3D printing), is the possibility of improving temperature management in the component 10, 110, 210 and therefore process stability in the additive manufacturing of the component, achieved by printing functional complementary structures in, on or around the component.

[0056] The individualized filling structures make it possible to produce components - in particular also from semicrystalline plastics - which have improved mechanical properties and at the same time have an optimized surface quality.

[0057] When generating functional fill structures, cross-sectional areas and / or FFF process parameters within the component geometry are used to design the fill structures such that the FFF printing process is adapted at each individual layer, and thus the temperature distribution within the component can be influenced during the printing process.

[0058] Furthermore, the refill structure can be used to influence the extrusion process during FLM / FFF (e.g. optimizing the volume flow rate by keeping the extrusion speed as constant as possible), which can be advantageously used, for example, in the printing of high-performance plastics (used, for example, in medical technology (implants, devices), aerospace, automotive, ...) and here especially when printing semi-crystalline plastic variants as well.

[0059] In comparison to conventional support structures, the focus of the described functional supplementary structures is not on the purely geometrical stabilization of the component during the printing process, but on the temperature management of the component and therefore on the process stability of the additive manufacturing process.

[0060] In addition to the method described here for generating geometrically optimized functional complementary structures for each layer, cross-section dependent velocity adaptation can also be performed in the area of ​​complementary structures in the slicing scheme (G-code generation).

[0061] The starting point is, for example, an STL / STEP / OBJ / general CAD file.

[0062] This file is the first point of reference for the process optimization method.

[0063] Taking into account the geometry and process-related boundary conditions (cross-sectional area, overhang, number of builds per layer, materials, process parameters, etc.), the component is oriented relative to the build platform or print direction.

[0064] The component is then analyzed with respect to its cross-sectional area parallel to the build platform and / or with respect to printing process parameters. Following this analysis, functional complementary structures are generated that significantly improve thermal management during the printing process.

[0065] One goal of the design process of a functional supplemental structure according to the present invention may be to “homogenize” the temperature throughout the component 10, 110, 210, for example, to achieve improved mechanical properties or reduced warpage in the component 10, 110, 210.

[0066] The replenishment structure 12, 112, 212 likewise makes it possible to additively manufacture the components 10, 110, 210 with a filament emission (volume flow rate) that is as constant as possible, which has a very beneficial effect on melt formation at the nozzle, especially in extrusion processes such as the FLM / FFF method.

[0067] Goals of the design process for functional supplemental structures can also include, for example, cross-sectional tailoring of mechanical properties within a component (e.g., through different crystallization rates in the case of semi-crystalline polymers), creating hot spots within a component (e.g., to activate additives within a material), or avoiding heat buildup within a component (e.g., to prevent overheating of a heat-sensitive additive within a material (e.g., a pharmaceutical admixture)).

[0068] Complementary structures can be realized by modification of the original component geometry or by the generation of further separate geometric bodies. Functional complementary structures can be realized as thin-walled (e.g., connecting separated cross-sectional areas to create a consistent cross-sectional area) like scaffold or framework structures, porous structures, etc., and can take over / integrate the functions of traditional support structures (support of undercut geometries, component stabilization, bed adhesion, ...).

[0069] Easy removal of the refill structure is another design goal, which may be achieved by integrating a predetermined break point in the target or by integrating an easily removable structure (e.g., a porous structure).

[0070] The refill structures can optionally be made of different materials (2K or 3K printing).

[0071] By fine discretization in the z-direction during the analysis of the cross-sectional geometry (see, for example, Figs. 1 and 2), functional replenishing structures can be generated such that the total cross-section per layer remains approximately constant throughout the component. However, advantages in terms of process control / stability can already be achieved by a coarser discretization. Thus, precise "homogenization" of the cross-section can be aimed at, although it is not a mandatory requirement for the method.

[0072] Furthermore, the dynamic behavior (path planning) of the print head during additive manufacturing can optionally be taken into account when generating the refill structures, so that times per layer / component layer can be influenced in this way.

[0073] Additionally, the thermal characteristics of the printing process and extruded material can be taken into account during generation of the fill structure (e.g., inclusion of finite element approaches in the calculation of the fill structure geometry) to more specifically assess the energy input into the component.

[0074] Partial or complete automation of the design process for functional supplemental structures is advantageous and possible.

[0075] An example of a medical application where excellent mechanical properties must be combined with good surface properties are individualized cranial implants (see FIG. 3, component 210). These can be printed with semi-crystalline polymers (e.g., PEEK) by a printing process in combination with a functional complement structure similar to a frame, so that the temperature within the layer is "equalized" across the component, thus achieving high mechanical strength, good surface quality, and minimized geometric distortion.

[0076] The materials for the components and / or the replacement structure can be medically compatible plastics and / or at least one plastic that is absorbable by the human or animal body. These materials are of interest for a large number of applications for implants, so their use in the context of the present invention is particularly advantageous. In addition to the above-mentioned material PEEK, medically compatible plastics can include or be, for example, PEKK (polyetheretherketoneketone), PAEK (polyaryletherketone), PEI (polyetherimide), or PPSU (polyphenylsulfone), while plastics that can be resorbed by the human or animal body can include, for example, PCL (polycaprolactone), PDO (poly-p-dioxanone), PLLA (poly-L-lactide), PDLA (poly-D-lactide), PGA (polyglycolic acid), or PGLA (poly(lactide-co-glycolide)).

[0077] Furthermore, the refill structure may be implemented such that, in addition to the primary functions described above, a given portion of the refill structure is used for downstream QA processes. In particular, the refill structure may be designed such that, for example, test specimens may be taken from the refill structure for mechanical testing (e.g., tensile testing according to ISO 527 or bending testing according to ISO 178, or other testing), or, for example, test specimens may be taken from the refill structure for biological testing (e.g., chemical characterization according to ISO 10993-18 or cytotoxicity testing according to ISO 10993-5, or other testing). Thus, for each manufactured component, one or more test tokens are available with which the manufacturing process may be characterized.

[0078] Additionally, the refill structures may also serve as mechanical reinforcements for the manufactured component to prevent / minimize distortion within the component.

[0079] During the production of a component, large temperature gradients in the component occur in the cooling process of the plastic melt, resulting in non-uniform shrinkage of the component (especially when cooling from the melt temperature of the material to the glass transition temperature). Depending on the geometry and the manufacturing process, this can lead to distortion of the component. This distortion can be prevented / minimized by specially arranged stiffening structures. In particular, the supplementary structures can be designed such that the shrinkage of the material in the supplementary structures compensates for the shrinkage of the material in the component, thus minimizing distortion of the component.

[0080] The concept of functional complementary structures can be applied to other additive manufacturing processes in addition to FLM / FFF. [Explanation of symbols]

[0081] 10 Components 12 Replenishment structure 14 Base material 210 Components 212 Replenishment structure 214 Base material 310 Components 312 Replenishment structure 314 Base material S1 Section plane 1 S2 Section plane 2 A1_s Cross-sectional area of ​​the filling structure in cross-sectional plane 1 A1_p Cross-sectional area of ​​the component in section plane 1 A2_s Cross-sectional area of ​​the filling structure in cross-sectional plane 2 A2_p Cross-sectional area of ​​the component in section plane 2

Claims

1. A method for producing a component (10, 110, 210) by an additive manufacturing method, comprising at least the following steps: a production plan for said component (10, 110, 210) is generated from the digital data, - said component (10, 110, 210) is analyzed with respect to the structure of said component (10, 110, 210) and / or production parameters of said component (10, 110, 210) with respect to the temperature within said component (10, 110, 210) during production; and - supplemental structures (12, 112, 212) are added to said component (10, 110, 210) where said analysis reveals that said structure and / or said production parameters will result in a non-uniform temperature distribution during production. A method comprising:

2. 2. The method of claim 1, wherein the additive manufacturing method is a fused deposition modeling (FDM) method or a fused layer modeling (FLM) method or a fused filament fabrication (FFF) method.

3. The method of claim 2, wherein the complementary structures (12, 112, 212) are generated by modification of an original component geometry.

4. The method of claim 1 , wherein the complementary structure is generated by addition of at least one distinct geometric body.

5. The method of claim 4, wherein the supplementary structure (12, 112, 212) is formed from a material different from that of the component (10, 110, 210).

6. The method of claim 1, wherein a predetermined break point is created between the component (10, 110, 210) and the supplemental structure (12, 112, 212).

7. 2. The method of claim 1, wherein the material of the component (10, 110, 210) is or comprises a semi-crystalline polymer.

8. The method of claim 1, characterized in that the supplementary structure (12, 112, 212) is used as a strengthening and / or stabilizing structure for the cooling process of the component (10, 110, 210).

9. 2. The method of claim 1, wherein at least the adding of the supplemental structures (12, 112, 212) is performed semi-automatically or automatically.

10. A component (10, 110, 210) produced by the production method of any one of claims 1 to 9, comprising at least one supplementary structure (12, 112, 212).

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