阅读说明：本技术 用于fdm打印物品的光滑表面的打印方法 (Printing method for smooth surface of FDM printed article ) 是由 R·A·M·希克梅特 P·A·范哈尔 于 2019-08-30 设计创作，主要内容包括：本发明提供了一种用于通过熔融沉积成型生产3D物品(1)的方法,方法包括：-3D打印阶段,包括逐层沉积包括可3D打印材料(201)的挤出物(321),其中在3D打印阶段的至少部分期间,挤出物(321)包括芯-壳挤出物(1321),芯-壳挤出物(1321)包括：包括芯材料(2011)的芯(2321)和包括壳材料(2012)的壳(2322),用于提供包括3D打印材料(202)的3D物品(1),其中3D物品(1)包括3D打印材料(202)的多个层(322),其中层(322)中的一个或多个层包括一个或多个芯-壳层部分(3322),其中芯-壳层部分(3322)中的每个芯-壳层部分包括：包括芯材料(2011)的层芯(3321)和包括壳材料(2012)的层壳(3322),其中3D物品(1)具有由3D打印材料(202)的至少部分限定的物品表面(252)；-暴露阶段,包括将所述物品表面(252)的至少部分暴露于液体(402),其中芯材料(2011)对液体(402)具有芯材料溶解度SC1,以及其中壳材料(2012)对液体(402)具有壳材料溶解度SS1,其中SC1＜SS2。(The invention provides a method for producing a 3D object (1) by fused deposition modeling, the method comprising: -a 3D printing phase comprising layer-by-layer deposition of an extrudate (321) comprising a 3D printable material (201), wherein during at least part of the 3D printing phase, the extrudate (321) comprises a core-shell extrudate (1321), the core-shell extrudate (1321) comprising: a core (2321) comprising a core material (2011) and a shell (2322) comprising a shell material (2012) for providing a 3D article (1) comprising a 3D printed material (202), wherein the 3D article (1) comprises a plurality of layers (322) of the 3D printed material (202), wherein one or more of the layers (322) comprise one or more core-shell portions (3322), wherein each of the core-shell portions (3322) comprises: a layer core (3321) comprising a core material (2011) and a layer shell (3322) comprising a shell material (2012), wherein the 3D article (1) has an article surface (252) defined by at least a portion of the 3D printed material (202); -an exposure phase comprising exposing at least part of the article surface (252) to a liquid (402), wherein the core material (2011) has a core material solubility SC1 for the liquid (402), and wherein the shell material (2012) has a shell material solubility SS1 for the liquid (402), wherein SC1 < SS 2.)

1. A method for producing a 3D object (1) by means of fused deposition modeling, the method comprising:

-a 3D printing phase comprising layer-by-layer deposition of an extrudate (321), the extrudate (321) comprising a 3D printable material (201), wherein during at least part of the 3D printing phase the extrudate (321) comprises a core-shell extrudate (1321), the core-shell extrudate (1321) comprising: a core (2321) comprising a core material (2011) and a shell (2322) comprising a shell material (2012), the core-shell extrudate (1321) for providing the 3D article (1) comprising a 3D printing material (202), wherein the 3D article (1) comprises a plurality of layers (322) of 3D printing material (202), wherein one or more of the layers (322) comprises one or more core-shell layer portions (3322), wherein each of the core-shell layer portions (3322) comprises: a layer core (3321) comprising the core material (2011) and a layer shell (3322) comprising the shell material (2012), wherein the 3D article (1) has an article surface (252) defined by at least a portion of the 3D printing material (202);

-an exposure phase comprising exposing at least part of the article surface (252) to a liquid (402), wherein the core material (2011) has a core material solubility SC1 for the liquid (402), and wherein the shell material (2012) has a shell material solubility SS1 for the liquid (402), wherein SC1 < SS2, wherein:

-the core material (2011) comprises one or more of: polycarbonate (PC), Polyethylene (PE), High Density Polyethylene (HDPE), polypropylene (PP), Polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), Polysulfone (PSU), Polyphenylene Sulfide (PPs), and semi-crystalline polyethylene terephthalate (PET); and

-the shell material (2012) comprises one or more of: acrylonitrile Butadiene Styrene (ABS), poly (methyl methacrylate) (PMMA), Polystyrene (PS), and styrene acrylic copolymer (SMMA).

2. The method of claim 1, wherein the liquid (402) comprises one or more of acetone and methyl ethyl ketone, and wherein the liquid (402) is applied by one or more of: flowing the liquid (402) over at least a portion of the item surface (252), spraying the liquid (402) onto at least a portion of the item surface (252), exposing at least a portion of the item surface (252) to a vapor comprising the liquid (402), and immersing at least a portion of the item surface (252) in the liquid (402).

3. The method of any of the preceding claims, wherein one or more of the article surface (252) or the liquid (402) has a temperature of at most 40 ℃ during the exposure phase, and wherein SC1/SS2 ≦ 0.5.

4. The method of any of the preceding claims, wherein the layer (322) has a layer height (H) and a layer width (W), wherein the layer height (H) is less than the layer width (W), wherein the method comprises: providing the one or more of the layers (322) during the printing stage, wherein the layer shell (3322) has a thickness that varies with a circumference (3331) of the layer core (3321), wherein a thickness (d4) of the layer shell (3322) in a height of a respective layer (322) of the one or more layers (322) is less than a thickness (d22) of the layer shell (3322) in a width of the respective layer (322).

5. The method according to any of the preceding claims, wherein the core material (2011) has a higher viscosity than the shell material (2012) at a temperature at which both the core material (2011) and the shell material (2012) are fluid.

6. The method according to any of the preceding claims, wherein the layer (322) has a layer height (H) and a layer width (W), wherein during the printing phase pressure is applied to the core-shell extrudate (1321) on a substrate (1550) to provide the layer (322) of 3D printing material (202) on the substrate (1550), the layer having a layer height (H) being smaller than the layer width (W).

7. The method of any preceding claim, further comprising: use of a printer nozzle (502), wherein the printer nozzle (502) comprises a core-feed nozzle (5021) and a shell-feed nozzle (5022) configured to provide the core-shell extrudate (1321), wherein the core-feed nozzle (5021) has a maximum core nozzle width (w11) and a minimum core nozzle width (w12), wherein the shell-feed nozzle (5022) has a maximum shell nozzle width (w21) and a minimum core nozzle width (w22), wherein w21 > w22, w21 > w11, w21 > w12, and wherein w12 ≧ w 11.

8. The method of claim 7, the method comprising applying a fused deposition modeling 3D printer (500), the fused deposition modeling 3D printer (500) comprising: (a) the printer nozzle (502) and (b) a substrate (1550), wherein the fused deposition modeling 3D printer (500) is configured to provide the 3D printable material (201) to the substrate (1550), wherein the nozzle (502) and the substrate (1550) are configured to be rotatable relative to each other, and wherein the method further comprises: maintaining the nozzle (502) and the substrate (1550) in a configuration that: such that the maximum core nozzle width (w11) is configured to be perpendicular to the 3D printing direction during at least part of the printing phase.

9. The method of any preceding claim, further comprising: exposing at least part of the article surface (252) to the liquid (402) until a predetermined average surface roughness (Ra) of the surface (205) of the 3D article is obtained, wherein for at least 25mm²The predetermined average surface roughness (Ra), etcAt or below 5 μm.

10. A 3D article (1) comprising 3D printed material (202), wherein the 3D article (1) comprises a plurality of layers (322) of 3D printed material (202), wherein one or more of the layers (322) comprise one or more core-shell layer portions (3322), wherein each of the core-shell layer portions (3322) comprises: a layer core (3321) comprising the core material (2011) and a layer shell (3322) comprising the shell material (2012), wherein the 3D article (1) has an article surface (252) defined by at least a portion of the 3D printing material (202), wherein the layer shell (3322) has a layer thickness (D22) at the article surface (252), wherein the layer shell (3322) has an intermediate layer thickness (D4) between adjacent layers (322), wherein the average layer thickness (D3) is greater than the intermediate layer thickness (D4), wherein:

-the core material (2011) comprises one or more of: polycarbonate (PC), Polyethylene (PE), High Density Polyethylene (HDPE), polypropylene (PP), Polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), Polysulfone (PSU), Polyphenylene Sulfide (PPs), and semi-crystalline polyethylene terephthalate (PET); and

-the shell material (2012) comprises one or more of: acrylonitrile Butadiene Styrene (ABS), poly (methyl methacrylate) (PMMA), Polystyrene (PS), and styrene acrylic copolymer (SMMA),

wherein the core material (2011) has a core material solubility SC1 for a liquid (402), and wherein the shell material (2012) has a shell material solubility SS1 for the liquid (402), wherein SC1 < SS2, and

wherein the 3D article surface (252) has an average surface roughness (Ra) for at least 25mm²The average surface roughness (Ra) being equal to or lower than 5 μm.

11. A lighting device (1000) comprising the 3D article (1) according to claim 10, wherein the 3D article (1) is configured as one or more of: at least part of the lighting device housing, a wall of the lighting chamber and an optical element.

Technical Field

The present invention relates to a method for manufacturing a 3D (printed) article and a software product for performing such a method. The invention also relates to a 3D (printed) article obtainable with such a method. Further, the invention relates to a lighting device comprising such a 3D (printed) article.

Background

The use of extruded 3D printer input containing layers is well known in the art. WO2015/077262, for example, describes a 3D printer input comprising a filament comprising separate layers or sections. In particular, these inputs comprising filaments can be prepared by co-extrusion, microlayer co-extrusion or multi-component/fractal co-extrusion. In the so-called 3D printing process, these inputs (in particular the filaments) enable different materials to be layered or combined simultaneously through one or more nozzles. These techniques facilitate smaller layer sizes (millimeters, micrometers, and nanometers), different layer configurations, and the potential to consolidate materials that are not available in standard 3D printer methods.

WO2018/106705 discloses a 3D printed core-sheath filament having an elongated core radially surrounded by a sheath with a barrier layer in between. The elongate core comprises a ductile polymer and the housing comprises a rigid polymer having a young's modulus higher than the young's modulus of the ductile polymer.

Disclosure of Invention

Digital manufacturing will gradually change the nature of the global manufacturing industry over the next 10 to 20 years. One of the aspects of digital manufacturing is 3D printing. Currently, many different technologies have been developed to produce various 3D printed objects using various materials (such as ceramics, metals, and polymers). 3D printing can also be used to produce molds, which can then be used to replicate objects.

To make molds, polymer injection techniques have been suggested. This technique utilizes layer-by-layer deposition of photopolymerizable materials that are cured after each deposition to form a solid structure. While this technique produces smooth flat surfaces, photocurable materials are not very stable and they also have low thermal conductivity useful for injection molding applications.

The most widely used additive manufacturing technique is a process known as Fused Deposition Modeling (FDM). Fused Deposition Modeling (FDM) is an additive manufacturing technique commonly used for molding, prototyping, and production applications. FDM works on the "additive" principle by layering material; the plastic wire or wire is unwound from the coil and material is provided to produce the part. It may be the case that (for example for thermoplastics) the filaments are melted and extruded before laying. FDM is a rapid prototyping technique. Other terms for FDM are "fuse fabrication" (FFF) or "filament 3D printing" (FDP), which are considered equivalent to FDM. Typically, FDM printers use thermoplastic filaments that are heated to their melting point and then extruded layer by layer (or indeed filament by filament) to create a three-dimensional object. FDM printers are fast and can be used to print complex objects.

FDM printers are fast, low cost, and can be used to print complex 3D objects. Such printers are used to print various shapes using various polymers. Techniques have also been developed to produce LED light fixtures and lighting solutions.

Fused Deposition Modeling (FDM) is one of the most common techniques for producing objects based on additive manufacturing (3D printing). FDM works on the "additive" principle by laying plastic material in layers. This typically results in a rough ribbed finish due to the nature of the process. This may not always be required, for example for decorative reasons, but also for functional reasons, such as the reflectivity of the surface, the treatability of the surface, etc. Thus, in some applications, a smooth surface is required. For this purpose, various post-surface treatment methods such as mechanical polishing and solvent treatment may be used.

The heat treatment of the entire 3D printed product may result in a weakening of the product, thereby losing shape and/or functionality. Solvent or solvent vapor treatment may also be used to obtain a smooth surface. In these processes, the object may be immersed in a solvent or placed in a solvent vapor, for example. However, the use of these techniques is largely successful when a large number of objects are used. During processing, solvent molecules penetrate the polymer ("3D printing material") and partially dissolve it. When a thin layer is used, it can lead to crack formation and/or delamination and deformation of the object.

Accordingly, an aspect of the present invention provides an alternative 3D printing method and/or 3D (printed) article, which also preferably at least partly obviates one or more of the above-mentioned disadvantages. It may therefore be an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art or to provide a useful alternative.

It is proposed herein, among other things, to use a wire with substantially concentric layers or to use a printer nozzle and wire feeder so that the two materials exit the nozzle and form core-shell layers next to each other or stacked on top of each other. The material may be selected such that the outer surface is made of a polymer that is soluble in the solvent that will be used for solvent treatment, but in which polymer the core material does not swell or dissolve. Objects printed in this manner may have a layer with an outer surface that may be at least partially dissolved by a solvent, while the inner material is not affected by the solvent. Placing the object in a solvent or in a solvent vapor, the outer polymer is made to flow, resulting in a smooth surface structure, while the inner polymer can essentially maintain mechanical integrity and avoid structure cracking and collapse.

Accordingly, in a first aspect, the present invention provides a method for producing a 3D article by fused deposition modeling, the method comprising a 3D printing stage and an exposure stage (in particular a 3D printed article obtained in the 3D printing stage). The 3D printing phase comprises depositing an extrudate comprising the 3D printable material layer by layer, wherein during at least part of the 3D printing phase, the extrudate comprises a core-shell extrudate comprising: (i) a core comprising a core material, and (ii) a shell (or "jacket") comprising a shell material. Thus, a 3D article may be provided comprising a 3D printed material, wherein the 3D article in particular comprises a plurality of layers of the 3D printed material, wherein one or more of the layers comprises one or more core-shell portions, wherein each of the core-shell portions comprises: a core layer comprising a core material and a shell layer comprising a shell material, wherein the 3D article has an article surface defined by at least a portion of the 3D printed material. Further, the exposure phase may in particular comprise exposing at least part of the surface of the article to a liquid, wherein the shell material may dissolve. Thus, in particular, the core material has a core material solubility SC1 for the liquid and the shell material has a shell material solubility SS1 for the liquid, where SC1 < SS 2. In particular embodiments, the core material comprises one or more of: polycarbonate (PC), Polyethylene (PE), High Density Polyethylene (HDPE), polypropylene (PP), Polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), Polysulfone (PSU), Polyphenylene Sulfide (PPs), and (semi-crystalline) polyethylene terephthalate (PET). In further specific embodiments, the shell material comprises one or more of: acrylonitrile Butadiene Styrene (ABS), poly (methyl methacrylate) (PMMA), Polystyrene (PS), and styrene acrylic copolymer (SMMA).

Accordingly, the present invention provides, inter alia, a method of producing a 3D article by means of fused deposition modeling, the method comprising:

-a 3D printing phase comprising layer-by-layer deposition of an extrudate comprising a 3D printable material, wherein during at least part of the 3D printing phase the extrudate comprises a core-shell extrudate comprising: a core comprising a core material and a shell comprising a shell material for providing a 3D article comprising a 3D printed material, wherein the 3D article comprises a plurality of layers of the 3D printed material, wherein one or more of the layers comprises one or more core-shell layer portions, wherein each of the core-shell layer portions comprises: a layer core comprising a core material and a layer shell comprising a shell material, wherein the 3D article has an article surface defined by at least a portion of the 3D printed material;

-an exposure phase comprising exposing at least part of the surface of the article to a liquid, wherein the core material has a core material solubility SC1 for the liquid, and wherein the shell material has a shell material solubility SS1 for the liquid, wherein SC1 < SS2, wherein:

-the core material comprises one or more of: polycarbonate (PC), Polyethylene (PE), High Density Polyethylene (HDPE), polypropylene (PP), Polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), Polysulfone (PSU), Polyphenylene Sulfide (PPs), and (semi-crystalline) polyethylene terephthalate (PET); and-the shell material comprises one or more of: acrylonitrile Butadiene Styrene (ABS), poly (methyl methacrylate) (PMMA), Polystyrene (PS), and styrene acrylic copolymer (SMMA).

With this approach, a 3D printed article may be provided, wherein at least part of the surface of the article may be much smoother than a surface not exposed to the liquid. Further, crack formation and/or delamination may be improved. Without exposure to liquid, the article surface may have a characteristic ribbed structure, such as in the case of FDM printed 3D articles. However, due to the exposure, the parts of the surface of the article exposed to the liquid obtain a smoother surface, with less roughness. In particular, parts of the shell material can dissolve, by means of which a smoothing effect of at least parts of the surface of the object can be produced. Further, with the present invention, the mechanical properties that may be provided by the core material in particular may be less affected or not affected at all. The dissolution aspect may also have a time component. Thus, the shell material and the core material may be selected such that the portion of the surface of the article exposed to the liquid becomes smoother over a predetermined period of time, and the desired smoothness may be achieved, while the core material does not substantially dissolve during that period of time. Thus, with this method, after heating, the surface roughness can be reduced from e.g. the μm size of the filament to the nm size. Further, with this method, smoothing can be performed relatively easily. If desired, the entire article may be exposed to the liquid without substantially losing shape and/or functionality. Further, with this method, the backbone material, which may consist essentially of the core material in each filament, may remain essentially unchanged when the surface is made smooth. Thus, a powerful device with a relatively smooth surface may be provided.

As mentioned above, the method is particularly useful for producing 3D articles by Fused Deposition Modeling (FDM). The method comprises two phases, a 3D printing phase and an exposure phase, wherein the latter is typically later than the former, although in other embodiments there may be some overlap in time (see also below). The method may also comprise one or more further stages, such as a heating stage also for smoothing the surface. Thus, there may be finishing stages, including an exposure stage to a liquid and optionally a heating stage. In addition to the term "finishing stage", the term "post-treatment" or similar terms may also be applied. Other stages may also be available.

Further, the term "stage" may also refer to a series of stages, such as for example a series of printing stages, wherein between these stages one or more functional or other components are integrated or provided on the 3D printed material thus obtained.

The 3D printing phase comprises depositing an extrudate comprising the 3D printable material layer by layer, wherein during at least part of the 3D printing phase, the extrudate comprises a core-shell extrudate comprising: a core comprising a core material and a shell comprising a shell material to provide a 3D article comprising a 3D printed material. Thus, the 3D printing process particularly provides a 3D article comprising a plurality of layers of 3D printing material, particularly formed as a result of layer-by-layer deposition.

As described above, during at least part of the 3D printing stage, the extrudate comprises a core-shell extrudate. The phrase indicates that during the printing phase, it is also possible to perform 3D printing, wherein not a core-shell extrudate is provided, but an extrudate of a single material, with substantially no compositional differences over the entire cross-section of the extrudate (i.e. "normal" 3D printing with a single nozzle). This may be achieved by stopping the feeding of material to the core or shell part of the printer head, in such a way that only a single material may escape from the nozzle and be deposited as an extrudate (see also below).

In some embodiments, a core-shell extrudate may be obtained by using a core-shell filament that is fed to the printer head and exits (at least partially melted) the nozzle of the printer head. In other embodiments, the core-shell extrudate is obtained by using a core-shell nozzle (i.e. a nozzle comprising two openings) which provide the core-shell extrudate when the 3D-printable material is forced through the nozzle.

It is noted that in particular embodiments, the term "core-shell" may also refer to a core-shell having a plurality of different shells. However, for a more detailed description of the invention, essentially only core-shell extrudates or core-shell parts consisting of a core and a (single) shell will be discussed below. In embodiments, the core may be comprised of a core and one or more shells that together form the core. Such a core is at least partially surrounded by a shell. Thus, herein, the term "shell" particularly refers to an outer layer or a set of outer layers (e.g., in embodiments, when the shell may include a plurality of shells).

To provide the core-shell material, a core-shell nozzle (printer head with core-shell nozzle) may be applied, as is well known in the art (see also above).

Thus, during at least part of the 3D printing stage, the extrudate comprises a core-shell extrudate. The core-shell extrudate comprises: a core comprising a core material and a shell comprising a shell material.

One or more of the layers comprises one or more core-shell portions, wherein each of the core-shell portions comprises: a core layer comprising a core material and a shell layer comprising a shell material. When the entire layer is printed as a core-shell layer, the entire layer may be represented as a core-shell portion or a core-shell layer. However, when the supply of core or shell material to the nozzle is (temporarily) terminated during printing of the layer, the portion of the layer will not be of the core-shell type, resulting in a layer comprising a core-shell layer portion (or portions) (and one or more non-core-shell portions).

Herein, the term "core-shell portion" is used. This reflects the fact that in an embodiment all layers may be core-shell layers, in an embodiment all parts of a layer may be core-shell layers, and in an embodiment a part of a layer (or parts of multiple layers) may be of the core-shell type. Thus, in embodiments, not all layers may be of the core-shell type, and in other embodiment layers, all layers may be of the core-shell type.

The core-shell portion may have a length of less than 1mm to several millimeters or more. Since (in embodiments) the same nozzle may be used to provide both the core-shell (portion) and the non-core-shell portion, the thickness and height may be substantially the same as the non-core-shell (portion) that may be adjacent.

The 3D article thus obtained has an article surface defined by at least part of the 3D printed material. In particular, this article surface is (thus) defined by the shell material.

As described above, the method comprises: the 3D printable material is deposited during the printing phase. Here, the term "3D printable material" refers to a material to be deposited or printed, and the term "3D printable material" refers to a material obtained after deposition. These materials may be substantially identical, as the 3D printable material may particularly refer to the material in the printer head or extruder at high temperatures, and the 3D printable material refers to the same material, but will be deposited later. The 3D printable material is printed as a filament and deposited as such. The 3D printable material may be provided as a filament or may be formed as a filament. Thus, whatever starting material is applied, the filament comprising the 3D printable material is provided by the printer head and is 3D printed. The term "extrudate" may be used to define a 3D printable material downstream of the printer head, but not yet deposited. The latter is denoted as "3D printed material". In fact, the extrudate comprises a 3D printable material, as the material has not yet been deposited. When depositing a 3D printable material or extrudate, the material is therefore denoted as 3D printable material. In essence, the materials are the same materials in that the thermoplastic materials are essentially the same materials upstream of the printer head, downstream of the printer head, and as deposited.

Here, the term "3D printable material" may also be denoted as "printable material". The term "polymeric material" may in embodiments refer to a mixture of different polymers, but may in embodiments also essentially refer to a single polymer type having different polymer chain lengths. Thus, the term "polymeric material" or "polymer" may refer to a single type of polymer, but may also refer to a plurality of different polymers. The term "printable material" may refer to a single type of printable material, but may also refer to a plurality of different printable materials. The term "printed material" may refer to a single type of printed material, but may also refer to a plurality of different printed materials.

Thus, the term "3D printable material" may also refer to a combination of two or more materials. Typically, these (polymeric) materials have a glass transition temperature T_gAnd/or melting temperature T_m. The 3D printable material will be heated by the 3D printer to a temperature of at least the glass transition temperature, and typically at least the melting temperature, before exiting the nozzles. Thus, in particular embodiments, the 3D printable material includes a material having a glass transition temperature (T)_g) And/or melting point (T)_m) And the printer head action comprises: the 3D printable material is heated above the glass transition and, if it is a semi-crystalline polymer, above the melting temperature. In yet another embodiment, the 3D printable material includes a material having a melting point (T)_m) And the printer head action comprises: the 3D printable material to be deposited on the receiver article is heated to a temperature of at least the melting point. The glass transition temperature is generally different from the melting temperature. Melting is a transition that occurs in crystalline polymers. Melting occurs when the polymer chains fall out of their crystalline structure, becoming a disordered liquid.Glass transition is a transition that occurs for amorphous polymers (i.e., polymers in which the chains are not arranged in ordered crystals, but are merely interspersed in any manner, even though they are solid). The polymer may be amorphous, have essentially a glass transition temperature without a melting temperature or may be (semi-) crystalline, typically having both a glass transition temperature and a melting temperature, wherein the latter is typically larger than the former. The glass temperature can be determined, for example, using differential scanning calorimetry. Melting points or melting temperatures can also be determined by differential scanning calorimetry.

As mentioned above, the present invention therefore provides a method comprising: providing a filament of 3D printable material, and printing the 3D printable material on a substrate in a printing stage to provide the 3D article.

Materials that may be particularly suitable as 3D printable materials may be selected from the group consisting of metal, glass, thermoplastic polymers, silicon, and the like. In particular, the 3D printable material comprises a (thermoplastic) polymer, the (thermoplastic) polymer is selected from the group consisting of ABS (acrylonitrile butadiene styrene), nylon (or polyamide), acetate (or cellulose), PLA (polylactic acid), terephthalate (such as PET polyethylene terephthalate), acrylic (polymethacrylate, plexiglass, polymethylmethacrylate PMMA), polypropylene fiber (or polypropylene), Polycarbonate (PC), Polystyrene (PS), PE (such as foamed high impact polyethylene (or polyethylene), Low Density (LDPE) High Density (HDPE)), PVC (polyvinyl chloride), or polyvinyl chloride (polycholotene) (thermoplastic elastomers such as copolyester elastomer, polyurethane elastomer, polyamide elastomer, polyolefin-based elastomer, styrene-based elastomer), and the like. Optionally, the 3D printable material comprises a 3D printable material selected from the group consisting of urea formaldehyde, polyester resins, epoxy resins, melamine formaldehyde, thermoplastic elastomers, and the like. Optionally, the 3D printable material comprises a 3D printable material selected from the group consisting of polysulfone. Elastomers, particularly thermoplastic elastomers, are particularly interesting because they are elastic and may contribute to obtaining relatively more elastic filaments, including thermally conductive materials. The thermoplastic elastomer may include one or more of the following: styrene block copolymers (TPS (TPE-s)), thermoplastic polyolefin elastomers (TPO (TPE-o)), thermoplastic vulcanizates (TPV (TPE-v or TPV)), Thermoplastic Polyurethanes (TPU)), thermoplastic copolyesters (TPC (TPE-E)), and thermoplastic polyamides (TPA (TPE-A)).

Suitable thermoplastic materials (such as also mentioned in WO 2017/040893) may include one or more of the following: polyacetals (e.g. polyoxyethylene and polyoxymethylene), polyacrylates (C)_1-6Alkyl), polyacrylamides, polyamides (e.g., aliphatic polyamides, polyphthalamides, and polyaramides), polyamideimides, polyanhydrides, polyarylates, polyarylethers (e.g., polyphenylene ethers), polyarylene sulfides (e.g., polyphenylene sulfides), polyarylsulfones (e.g., polyphenylsulfones), polybenzothiazoles, polybenzoxazoles, polycarbonates (including polycarbonate copolymers, such as polycarbonate-siloxanes, polycarbonate-esters, and polycarbonate-ester-siloxanes), polyesters (e.g., polycarbonates, polyethylene terephthalates, polyethylene naphthalates, polybutylene terephthalates, polyarylates, and polyester copolymers (such as polyester-esters), polyether ether ketones, polyetherimides (including copolymers, such as polyetherimide-siloxane copolymers), polyether ketone ketones, polyaryl ether ketones, polyaryl amides, polyamide imides, polyaryl esters, and copolymers (such as polycarbonate, Polyethersulfones, polyimides (including copolymers such as polyimide-siloxane copolymers), polymethylacrylates (C)_1-6Alkyl), polymethacrylamide, polynorbornene (including copolymers containing norbornene units), polyolefins (e.g., polyethylene, polypropylene, polytetrafluoroethylene and polymers thereof, e.g., ethylene-alpha-olefin copolymers), polyoxadiazole, polyoxymethylene, polyphthalamide, polysilazane, polysiloxane, polystyrene (including copolymers such as acrylonitrile-butadiene-styrene (ABS) and methyl Methacrylate (MBS)), polysulfide, polysulfonamide, polysulfonate, polysulfone, polythioester, polytriazine, polyurea, polyurethane, polyvinyl alcohol ester, polyether, polyvinyl alcohol halide, polyvinyl ketone, polyphenylene sulfide, polyvinylidene fluoride, and the like, or combinations comprising at least one of the foregoing thermoplastic polymers. Examples of polyamides may include, but are not limited to, synthetic linearPolyamides, such as nylon-6, such as nylon-6, 9, nylon-6, 10, nylon-6, 12, nylon-11, nylon-12 and nylon-4, 6, preferably nylon 6 and nylon 6,6 or a combination comprising at least one of the foregoing. Polyurethanes which may be used include aliphatic, cycloaliphatic, aromatic and polycyclic polyurethanes, including the polyurethanes described above. Also useful are polyacrylates (C)_1-6Alkyl) and polymethyl acrylate (C)_1-6Alkyl) including, for example, polymers of methyl acrylate, ethyl acrylate, acrylamide, methacrylic acid, methyl methacrylate, n-butyl acrylate, and ethyl acrylate, and the like. In embodiments, the polyolefin may comprise one or more of the following: polyethylene, polypropylene, polybutene, polymethylpentene (and copolymers thereof), polynorbornene (and copolymers thereof), polybutene-1, poly (3-methylbutene), poly (4-methylpentene), and copolymers of ethylene with propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 1-octadecene.

The term "3D printable material" is also elucidated below, but especially refers to a thermoplastic material, optionally comprising additives, with a maximum volume percentage of about 60%, especially a maximum of about 30 vol.%, such as a maximum of 20 vol.% (additives relative to the total volume of thermoplastic material and additives).

Thus, in an embodiment, the printable material may comprise two phases. The printable material may comprise a phase, in particular a thermoplastic material (see also below), of printable polymer material, in particular an essentially continuous phase. In this continuous phase of the thermoplastic polymer, additives may be present, such as one or more of the following: antioxidants, heat stabilizers, light stabilizers, ultraviolet light absorbing additives, near infrared light absorbing additives, plasticizers, lubricants, mold release agents, antistatic agents, antifogging agents, antibacterial agents, colorants, laser marking additives, surface effect additives, radiation stabilizers, combustion improvers, and anti-drip agents. The additives may have useful properties selected from optical, mechanical, electrical, thermal and mechanical properties (see also above).

In an embodiment, the printable material may comprise particulate material, i.e. particles embedded in the printable polymer material, which particles form a substantially discontinuous phase. The amount of particles in the total mixture is in particular not more than 60 vol.%, relative to the total volume of the printable material (comprising (anisotropically conductive) particles), in particular in applications for reducing the coefficient of thermal expansion. For optical and surface related effects, the amount of particles in the total mixture is equal to or less than 20 vol.%, such as up to 10 vol.%, relative to the total volume of printable material (including particles). Thus, 3D printable material especially refers to a continuous phase of thermoplastic material in nature, in which other materials such as particles may be embedded. Likewise, 3D printed material particularly refers to a continuous phase of thermoplastic material in nature, in which other materials such as particles may be embedded. The particles may include one or more of the additives described above. Thus, in an embodiment, the 3D printable material may comprise a particulate additive.

As mentioned above, the 3D printable material of the shell may be different from the 3D printable material of the core. Thus, in embodiments, the core material has a different composition than the shell material. In particular, the core material and the shell material each comprise a thermoplastic polymer. In particular, the thermoplastic polymers differ in composition. This may be useful for forming a good core-shell extrudate (or filament), and this may allow the shell to dissolve relatively quickly, while the core is essentially insoluble.

In particular embodiments, the polymers are incompatible. Incompatible polymers cannot be mixed at the molecular level. When mixed together, they become phase separated. Thus, the core material may comprise a first polymer and the shell material may comprise a second polymer, wherein the first polymer and the second polymer are incompatible. Thus, in particular embodiments, the core material and the shell material comprise different thermoplastic materials. In an embodiment, the core material may comprise a first thermoplastic material and the shell material may comprise a second thermoplastic material different from the first thermoplastic material.

As mentioned above, there may be a difference between the solubility (of the core material and the shell material) in the liquid used to smooth at least part of the surface during the liquid exposure phase. In particular, the core material has a core material solubility SC1 for the liquid, and wherein the shell material has a shell material solubility SS1 for the liquid, where SC1 < SS2, in particular SC1/SS2 ≦ 0.5 (such as at room temperature (generally considered as 20 ℃)), as in the examples, in the range of 0.1 to 0.8.

In particular embodiments, the core material comprises one or more of: polycarbonate (PC), Polyethylene (PE), High Density Polyethylene (HDPE), polypropylene (PP), Polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), Polysulfone (PSU), Polyphenylene Sulfide (PPs), and (semi-crystalline) polyethylene terephthalate (PET). Thus, the core material may comprise one or more different thermoplastic materials. As mentioned above, in addition, other materials may be useful, such as particulate materials embedded in the core material.

Further, in particular embodiments, the shell material comprises one or more of: acrylonitrile Butadiene Styrene (ABS), poly (methyl methacrylate) (PMMA), Polystyrene (PS), and styrene acrylic copolymer (SMMA). Thus, the shell material may comprise one or more different thermoplastic materials. As mentioned above, in addition, other materials may be useful, such as particulate materials embedded in the core material.

Further, it may be desirable for the materials to differ in some (other) respects. In a particular embodiment, the core material has a core material viscosity and the shell material has a shell material viscosity, wherein the core material viscosity is particularly high at temperatures above the core glass temperature (Tg1) or core melting temperature Tm. This may allow good processing during the printing phase. Preferably, shorter chain length molecules are used for the shell. This causes the material to flow faster to obtain a smooth surface. Melt flow rate, in particular as defined by ISO-113 under conditions (300 ℃ C.; 1.2kg), in particular higher than 20cm³10 minutes, more particularly above 50cm³10 minutes and most particularly above 100cm³10 minutes. In particular embodiments, the polymeric materials of the core and shell may be incompatible. This may particularly imply that at the interface of the two layers (of core and shell) theThere is substantially no mixing. The adhesion between the filaments may in particular be provided by the shell.

It may also be useful when the shell material has a lower viscosity. This may facilitate removal of the shell at the surface of the article. Thus, in embodiments, the core material has a higher viscosity than the shell material at temperatures at which both the core material and the shell material are fluid. For example, in a particular embodiment, the core material has a core dynamic viscosity μ 1, and wherein the shell material has a shell dynamic viscosity μ 2, wherein μ 2/μ 1 < 0.8, such as in the range of 0.1 to 0.8.

The printable material is printed on the receiver item. In particular, the receiver article may be or may consist of a build platform. During 3D printing, the receiver article may also be heated. However, the receiver article may also be cooled during 3D printing.

In addition, the phrase "printing on the receiver article" and similar phrases also include printing directly on the receiver article or printing on a coating on the receiver article or printing on 3D printed material earlier printed on the receiver article. The term "receiver article" may refer to a printing platform, printing bed, base plate, support, build plate, or build platform, etc. In addition to the term "receiver article," the term "substrate" may also be used. In addition, the phrase "printing on a receiver article" and similar phrases also include printing on a separate substrate on or comprised of a printing platform, printing bed, support, build plate, or build platform, and the like. Thus, in addition to this, the phrase "printed on a substrate" and similar phrases also include printing directly on a substrate or on a coating printed on a substrate or on a 3D printed material earlier printed on a substrate. In the following, the term "substrate" is also used, which may refer to a printing platform, a printing bed, a substrate, a support, a build plate or build platform, etc., or a separate substrate thereon or consisting of them.

The printable material is deposited layer by layer, by which deposition a 3D printed item is generated (in the printing phase). The 3D printed article may exhibit a characteristic ribbed structure (from deposited filaments). However, after the printing phase, it is also possible to perform further phases, such as a finalization phase. This stage may include removing the printed article from the receiver article and/or one or more post-processing actions. One or more post-processing actions may be performed prior to removing the printed article from the receiver article and/or one or more post-processing actions may be performed after removing the printed article from the receiver article. For example, post-processing may include one or more of polishing, coating, adding functional components, and the like. Post-treatment may include smoothing the ribbed structure, which may result in a substantially smooth surface.

The liquid exposure may be performed in different ways. In embodiments, the exposure phase may include one or more of the following actions: providing the 3D printing material with hot gas comprising a liquid, providing the 3D printing material with a spray of droplets comprising a liquid, rinsing the 3D printing material with the liquid, and immersing the 3D printing material in the liquid. Optionally, when a portion of the surface is exposed to a liquid, that portion may also be exposed to some pressure and/or break.

Thus, in embodiments, the liquid may be applied by one or more of the following actions: the method includes flowing a liquid over at least a portion of the surface of the article, spraying the liquid onto at least a portion of the surface of the article, exposing at least a portion of the surface of the article to a vapor comprising the liquid, and immersing at least a portion of the surface of the article in the liquid. In an embodiment, the term "spraying" may include atomization.

The exposure to liquid may be performed after the 3D article is provided or after a portion thereof has been 3D printed. Thus, the exposure phase may occur during or after printing or both. The liquid exposure may be performed locally, e.g. local exposure of the just printed part, or the liquid exposure may be for the entire 3D printed article. When the entire 3D article enters the exposure phase, the exposure phase is of course after the 3D printing phase. Combinations of liquid exposure methods may also be applied. Thus, the printing phase and the exposure phase may be combined in time or may be performed sequentially.

Thus, in an embodiment, during the exposure phase, one or more of the article surface or the liquid has a temperature of at most 80 ℃, such as at most 50 ℃, such as at most 40 ℃. In particular, the liquid may have a temperature not greater than one of the indicated maximum temperatures.

Suitable liquids are those having a solubility for the shell material which is greater than the solubility for the core material, such as SC1 < SS2, in particular SC1/SS 2. ltoreq.0.5. In an embodiment, the liquid comprises one or more of acetone and methyl ethyl ketone. These liquids are particularly useful as solvents for one or more of ABS, PMMA, PS or SMMA. The term "liquid" may refer to a plurality of different liquids. The term "liquid" may refer to a variety of different solvents. One or more of these solvents may be a solvent for the shell material (not for the core material per se).

In particular, the exposure phase may result in removing portions of the shell material at least portions of the surface of the article. However, typically not all shell material is removed at least at parts of the surface of the article, but the layer thickness is reduced (i.e. in particular the width of the layer shell at the respective layer).

As described above, liquid exposure may result in a relatively smooth surface. In a particular embodiment, it is possible to obtain a surface roughness below 10 μm or even below 5 μm or even below 1 μm. Therefore, the heating may affect the reduction of the roughness. This can be measured, for example, by laser light scattering. Thus, in an embodiment, the method may further comprise: heating the 3D printed material until a predetermined average surface roughness (Ra) of the surface of the 3D object is obtained, wherein in particular for at least 25mm²(such as at least 100 mm)²) Predetermined average surface roughness (Ra) equal to or lower than 5 μm. In an embodiment, the entire outer surface of the 3D printed article may have such an average surface roughness.

In a specific embodiment, the core-shell extrudate has a core diameter (d1) selected from the range of 100 μm to 3000 μm, and wherein the shell thickness (d2) is selected from the range of 100 μm to 2000 μm, in particular up to about 1000 μm, such as in the range of 100 μm to 500 μm. The core-shell extrudate may be provided and printed as such or may be produced in a printer head, such as with a co-extrusion printer head. The maximum width may be selected when the core of the extrudate has a substantially circular cross-section rather than a core diameter. Such maximum width may also be in the range of about 100 μm to about 3000 μm. The shell thickness may then be defined as a maximum shell thickness, which may be in a range of about 100 μm to about 3000 μm, such as about 100 μm to about 2000 μm.

Due to the availability of the shell, the adhesion between the filaments may be affected. Thus, it may be desirable to make the thickness of the shell(s) between the filaments in the 3D printable material thinner, and in particular thinner, than the 3D printable material (i.e. the material that has not yet been printed).

Thus, in a particular embodiment, pressure is applied on the printable material while deposited on the support or receiver item (i.e., on the 3D printed material included on the receiver item). Such pressures may be particularly suitable for use in a printer head. In this way, a (core-shell) extrudate may be printed which does not have a substantially circular cross-sectional shape, but has a compressed tubular shape, such as extending along an axis. Thus, in a specific embodiment, during printing, pressure is applied to the (core-shell) extrudate to provide a deposited (core-shell) layer portion, which in the case of a core-shell layer may in embodiments have a deformed core having a first dimension (h1) and a second dimension (w1) perpendicular to each other and to the longitudinal axis (a) of the core-shell extrudate, which may in particular have a ratio (h1/w1) of less than 1, such as less than 0.9, such as less than 0.8, such as in the range of 0.2 to 0.6. As described above, during deposition of the 3D printable material, pressure may be applied with the printer head.

Thus, the method provides, inter alia, a layer having a layer height (H) and a layer width (W), wherein the layer height (H) is smaller than the layer width (W). This may be applicable to substantially all 3D printed layers (whether of the core-shell type or not). Particularly when printing core-shell extrudates, the method comprises: providing one or more of the layers during the printing stage, wherein the layer shells have a thickness that varies with the circumference of the layer core, wherein the thickness of the layer shells in the height of the respective layer in the one or more layers (d4) is less than the thickness of the layer shells in the width of the respective layer (d 22). At some locations between adjacent layers, the thickness of the layer shell in the height of the respective layer (d4) may even be zero μm. Thus, in particular embodiments, adjacent layers may be in physical contact with each other (and the core-to-core distance is substantially zero μm). During the exposure phase, the layer thickness d22 may decrease. The layer thickness d22 can be regarded as the maximum layer thickness of the shell in the width of the respective layer. The thickness d4 can be considered as the maximum layer thickness of the shell in the height of the layer. Typically, d22 > d4 or even d22 > d 4.

Thus, in an embodiment (layer having a layer height (H) and a layer width (W)), wherein during the printing phase pressure is applied to the core-shell extrudate on the substrate to provide a layer of 3D printed material on the substrate, the layer having a layer height (H) being smaller than the layer width (W). Thus, the shell thickness (d2) of the filament or extrudate can be (substantially) reduced when depositing the extrudate. Due to the pressure, d4 is reduced compared to the case where less or no pressure is applied. Further, the pressure d22 may be, although need not be, increased relative to the case where less or no pressure is applied.

Alternatively or additionally, to apply pressure, the particular nozzle geometry may be selected such that the shell thickness between layers is small and larger (much larger) at portions of the layer that are not in contact with adjacent layers (i.e., the side(s) of the layer).

Thus, in yet another embodiment, the method may further comprise using a printer nozzle, wherein the printer nozzle comprises a core-feed nozzle and a shell-feed nozzle configured for providing a core-shell extrudate, wherein in particular the core-feed nozzle has a maximum core nozzle width (w11) and a minimum core nozzle width (w12), wherein the shell-feed nozzle has a maximum shell nozzle width (w21) and a minimum core nozzle width (w22), wherein w21 > w22, w21 > w11, w21 > w12 and w12 ≧ w 11. In particular, the nozzles are arranged in line with each other, i.e. the centre of the shell feed nozzle and the centre of the core feed nozzle coincide or are arranged above each other; in the latter embodiment, the virtual line connecting the centers may be perpendicular to the nozzle. Thus, the condition of w21 > w22 may additionally or alternatively facilitate the formation of a compressive layer and a thinner shell between the layers. Thus, w21 may also be substantially the same as w22, but in particular embodiments w21 > w 22. When w21 ═ w22, the shell nozzle is circular or square. When w11 ═ w12, the core nozzle is circular or square. In particular, the core nozzle may be arcuate ("circular") and the shell nozzle is elliptical or rectangular. Note that in such an embodiment, the shell thickness d2 of the extrudate downstream of the nozzle varies from core to core.

In addition to the term "nozzle", the term "opening" or "nozzle opening" may also be applied.

In embodiments, the maximum core nozzle width (w11) is selected from the range of 100 μm to 3000 μm. Further, in embodiments, the maximum shell nozzle width (w21) is selected from the range of 100 μm to 3000 μm, such as in the range of 100 μm to 2000 μm. In further embodiments, the maximum core nozzle width (w11) is greater than the maximum shell nozzle width (w21) (such as oval or rectangular).

When printing with non-circular shell nozzles, it may still be necessary to apply pressure to the core-shell extrudate on the substrate.

When printing with non-circular shell nozzles, it may be necessary to rotate the nozzles relative to the substrate, which otherwise, when printing in a direction perpendicular to the previous direction, may result in some or substantially all of the core-shell structure. Rotation may be accomplished by rotating the printer head or by rotating the substrate or by both. All options are included herein in the phrase "relatively rotatable configuration" and similar phrases.

Thus, in a specific embodiment, the method may further comprise applying a fused deposition modeling 3D printer comprising (a) a printer nozzle and (b) a substrate, wherein the fused deposition modeling 3D printer is configured to provide a 3D printable material to the substrate, wherein the nozzle and the substrate are configured to be rotatable relative to each other, and wherein the method further comprises maintaining the configuration of the nozzle and the substrate such that the maximum core nozzle width (w11) is configured perpendicular to the 3D printing direction during at least part of the printing phase. To this end, the 3D printer software may be adjusted to allow control of the printing direction and nozzle-substrate configuration.

The software product may be capable of implementing the methods described herein when run on a computer. The computer may be functionally coupled to or may consist of a fused deposition modeling 3D printer. In particular, such a software product may be used to maintain the configuration of the nozzle and substrate such that the maximum core nozzle width (w11) is configured perpendicular to the 3D printing direction during at least part of the printing phase.

The methods described herein provide for 3D printed articles. The present invention therefore also provides, in a further aspect, a 3D printed article obtainable by the method described herein. In particular, the present invention provides a 3D article comprising a 3D printed material, wherein the 3D article comprises a plurality of layers of the 3D printed material, wherein one or more of the layers comprises one or more core-shell portions, wherein each of the core-shell portions comprises: a core layer comprising a core material and a shell layer comprising a shell material, wherein the 3D article has an article surface defined by at least a portion of the 3D printed material. In particular, the layer shell has a layer thickness (d22) at the surface of the article, wherein the layer shell has an intermediate layer thickness (d4) between adjacent layers, wherein the layer thickness (d22) is greater than the intermediate layer thickness (d 4). As described above, in some embodiments, the intermediate thickness may be substantially zero μm, resulting in physical contact or optionally even mixing of adjacent layers.

The core material comprises one or more of: polycarbonate (PC), Polyethylene (PE), High Density Polyethylene (HDPE), polypropylene (PP), Polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), Polysulfone (PSU), Polyphenylene Sulfide (PPs), and (semi-crystalline) polyethylene terephthalate (PET). The shell material includes one or more of: acrylonitrile Butadiene Styrene (ABS), poly (methyl methacrylate) (PMMA), Polystyrene (PS), and styrene acrylic copolymer (SMMA).

Some specific embodiments related to the above-described 3D printing method relate not only to the method, but also to the 3D printed article. Some specific embodiments related to 3D printed articles are discussed in more detail below.

For at least 25mm²Such as at least 10mm²Area of (2)) At least part of the surface of the 3D article has an average surface roughness (Ra) equal to or lower than 5 μm. Further, in an embodiment, the core material has a core material solubility SC1 for the liquid and the shell material has a shell material solubility SS1 for the liquid, where SC1 < SS2, such as SC1/SS2 ≦ 0.5.

As described above, in an embodiment, a layer of 3D printing material on a substrate may have a layer height (H) that is less than a layer width (W). In particular, in an embodiment, the layer shell has a thickness that varies with the circumference of the layer core, wherein the thickness of the layer shell in the height of the respective layer of the one or more layers (d4) is less than the thickness of the layer shell in the width of the respective layer (d 22). In further embodiments, the core material may have a higher viscosity than the shell material at a temperature at which both the core material and the shell material are fluid. For example, in an embodiment, the core material has a core dynamic viscosity μ 1, and wherein the shell material has a shell dynamic viscosity μ 2, where μ 2/μ 1 < 0.8.

As mentioned above, one or more of the core-shell portions (of the 3D printed material) have a deformed core having a first dimension (h1) and a second dimension (w1) perpendicular to each other and to the longitudinal axis (a) of the core-shell portion (of the 3D printed material), the core-shell portion having a ratio (h1/w1) of less than 1. In particular, this may apply for at least 50%, such as at least 70%, of all layers. Thus, over at least 50% of the total length of the layer has a deformed core. Further, adjacent cores may have a core-to-core distance (d23) selected from a range of at most 200 μm, such as at most 100 μm, such as at most 50 μm, or even smaller, such as at most 20 μm. In some embodiments, the core-to-core distance may be zero. The core-to-core distance is specifically defined as the shortest distance between cores of adjacent layers.

The 3D article described herein and obtainable with the method described herein may be substantially any kind of article. Here, the 3D object is in particular an object, which may be partially hollow or may be bulky. The 3D object may be a plate, a shaped article, or the like. Specific examples of articles that may be created with the present invention and that may be the result of the methods described herein are, for example, optical (semi-transparent) filters, reflectors, light mixing chambers, collimators, compound parabolic concentrators, and the like.

The 3D printed article thus obtained may itself be functional. For example, the 3D printed article may be a lens, a collimator, a reflector, or the like. The 3D object thus obtained may (alternatively) be used for decorative or artistic purposes. The 3D printed article may comprise or be provided with functional components. The functional component may be selected in particular from the group consisting of an optical component, an electrical component and a magnetic component. The term "optical component" especially refers to a component having optical functionality, such as a lens, a mirror, a light source (e.g. an LED), etc. The term "electrical component" may for example refer to an integrated circuit, a PCB, a battery, a driver, but also to a light source (as a light source may be considered as an optical component and an electrical component), etc. The term "magnetic component" may for example refer to a magnetic connector, a coil, etc. Alternatively or additionally, the functional component may comprise a thermal component (e.g. configured to cool or heat an electrical component). Thus, the functional components may be configured to generate heat or remove heat, or the like.

As mentioned above, the 3D printed article may be used for different purposes. The 3D printed article may be used for illumination, among other things. Accordingly, in a further aspect, the invention also provides a lighting device comprising a 3D article as defined herein. In particular, the 3D article may be configured as one or more of: at least part of the lighting device housing, a wall of the lighting chamber and an optical element. The 3D printed article may be used as a mirror or a lens, etc. since a relatively smooth surface may be provided.

Returning to the 3D printing process, a particular 3D printer may be used to provide the 3D printed article described herein, such as a fused deposition modeling 3D printer, including: (a) a printer head comprising a printer nozzle, and (b) a 3D printable material providing device configured to provide the 3D printable material to the printer head, wherein the fused deposition modeling 3D printer is configured to provide the 3D printable material to the substrate, wherein the printer nozzle comprises a core feed nozzle configured to provide a core-shell extrudate and a shell feed nozzle, wherein the core feed nozzle has a maximum core nozzle width (w11) and a minimum core nozzle width (w12), wherein the shell feed nozzle has a maximum shell nozzle width (w21) and a minimum core nozzle width (w22), wherein the fused deposition modeling 3D printer may further comprise a control system (C), wherein the control system (C) is configured to perform the above method.

The control system (C) may be configured to perform a method to maintain the configuration of the nozzles and the substrate such that the maximum core nozzle width (w11) is configured perpendicular to the 3D printing direction during at least part of the printing phase.

The 3D printable material providing device may provide the filament comprising the 3D printable material to a printer head or may likewise provide the 3D printable material, wherein the printer head produces the filament comprising the 3D printable material. Accordingly, in an embodiment, the present invention provides a fused deposition modeling 3D printer comprising: (a) a printer head comprising a printer nozzle, and (b) a filament providing device configured to provide a filament comprising a 3D printable material to the printer head, wherein the fused deposition modeling 3D printer is configured to provide the 3D printable material to a substrate, wherein the printer nozzle comprises a core feed nozzle and a shell feed nozzle configured to provide a core-shell extrudate, wherein the core feed nozzle has a maximum core nozzle width (w11) and a minimum core nozzle width (w12), wherein the shell feed nozzle has a maximum shell nozzle width (w21) and a minimum core nozzle width (w22), wherein in an embodiment the fused deposition modeling 3D printer further comprises a control system (C), wherein the control system (C) is configured to perform the above method.

The control system (C) may be configured to perform a method to maintain the configuration of the nozzles and the substrate such that the maximum core nozzle width (w11) is configured perpendicular to the 3D printing direction during at least part of the printing phase.

In addition to the term Fused Deposition Modeling (FDM)3D printer, the acronym "3D printer", "FDM printer", or "printer" may also be used. The printer nozzle may also be denoted as a "nozzle", or sometimes as an "extruder nozzle".

Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

1 a-1 c schematically depict some general aspects of a 3D printer and 3D printed material;

FIGS. 2 a-2 f schematically depict aspects of the present invention;

fig. 3 a-3 c schematically depict some aspects related to deposited extrudates;

fig. 4 shows roughness measurements using DEKTAK on two sections of untreated objects (U1 and U2) and acetone treated objects (a) made using a core-shell nozzle with ABS in the shell and PP in the core with a layer thickness of 800 μm.

Fig. 5 schematically depicts aspects of the invention.

The schematic drawings are not necessarily drawn to scale.

Detailed Description

Fig. 1a schematically depicts some aspects of a 3D printer. Reference numeral 500 denotes a 3D printer. Reference numeral 530 denotes a functional unit configured to perform 3D printing (in particular, FDM3D printing); the reference mark may also indicate a 3D printing phase unit. Here, a printer head for providing 3D printed material, such as an FDM3D printer head, is only schematically depicted. Reference numeral 501 denotes a printer head. The 3D printer of the present invention may specifically comprise a plurality of printer heads, although other embodiments are possible. Reference numeral 502 denotes a printer nozzle. The 3D printer of the present invention may specifically comprise a plurality of printer nozzles, although other embodiments are also possible. Reference numeral 321 represents a printable filament of 3D printable material (as described above). For the sake of clarity not all features of the 3D printer have been described, only those features that are particularly relevant to the present invention are described (see also below).

The 3D printer 500 is configured to generate a 3D article 1 by depositing a plurality of filaments 321 layer-by-layer on a receiver article 550, which receiver article 550 may be at least temporarily cooled in embodiments,wherein each filament 321 comprises a 3D printable material 201, such as having a melting point T_m. The 3D printable material 201 may be deposited on the substrate 1550 (during the printing phase).

The 3D printer 500 is configured to heat the filament material upstream of the printer nozzle 502. This may be done, for example, with a device that includes one or more of the extrusion and/or heating functions. Such an apparatus is designated by reference numeral 573 and is disposed upstream of the printer nozzle 502 (i.e., at a time before the filament material exits the printer nozzle 502). The printer head 501 (thus) may include a liquefier or heater. Reference numeral 201 denotes a printable material. When deposited, the material is represented as (3D) printed material, indicated with reference numeral 202.

Reference 572 indicates a reel or roller with material, in particular in the form of a wire, which may be indicated as wire 320. The 3D printer 500 converts it in a filament 321 downstream of the printer nozzle, which becomes a layer 322 on the receiver article or on the already deposited printing material. Typically, the diameter of the filament 321 downstream of the nozzle is reduced relative to the diameter of the filament 322 upstream of the printer head. Thus, the printer nozzle is sometimes (also) indicated as an extruder nozzle. Layer 322 is disposed next to layer 322 and/or layer 322t is disposed on layer 322, which may form 3D article 1. Reference 575 denotes a wire feeding apparatus that includes, among other things, a spool or roller and a drive wheel, denoted by reference 576.

Reference character a denotes a longitudinal axis or a wire axis.

Reference character C schematically depicts a control system, such as in particular a temperature control system configured to control the temperature of receiver article 550. Control system C may include a heater capable of heating receiver article 550 to a temperature of at least 50℃, but particularly up to a range of about 350℃, such as at least 200℃.

Alternatively or additionally, in embodiments, the receiver plate may also be moved in one or two directions in the x-y plane (horizontal plane). Further, alternatively or additionally, in embodiments, the receiver plate may also be rotatable about the z-axis (vertical). Thus, the control system may move the receiver plate in one or more of the x-direction, y-direction, and z-direction.

Alternatively, the printer may have a head, which may also rotate during printing. Such a printer has the advantage that the printing material cannot rotate during printing.

The layer is indicated by reference numeral 322 and has a layer height H and a layer width W.

It is to be noted that the 3D printable material does not have to be provided to the printer head as the filament 320. Further, the filament 320 may also be produced in the 3D printer 500 from fragments of 3D printable material.

Reference D denotes the diameter of the nozzle through which the 3D printable material 201 is forced.

Fig. 1b schematically depicts in more detail in 3D the printing of the 3D article 1 under construction. Here, in this schematic view, the ends of the wire 321 in a single plane are not interconnected, although in fact this may be the case in embodiments. Reference character H denotes the height of the layer. The layer is denoted with reference numeral 203. Here, the layer has a substantially circular cross-section. However, in general, they may be flat, such as having an outer shape like a flattened oval tube or flattened oval conduit (i.e. a circular rod whose diameter is compressed to a height less than the width, wherein the (width-defining) sides are (still) circular).

Accordingly, fig. 1 a-1 b schematically depict some aspects of a fused deposition modeling 3D printer 500, including: (a) a first printer head 501 including printer nozzles 502; (b) a filament providing device 575 configured to provide a filament 321 comprising 3D printable material 201 to a first printer head 501; and optionally (c) a receiver article 550. In fig. 1a to 1b, the first printable material or the second printable material or the first printed material or the second printed material is represented by the general indication printable material 201 and printed material 202. Directly downstream of the nozzle 502, the filament 321 with the 3D printable material becomes the layer 322 with the 3D printable material 202 when deposited.

Fig. 1c schematically depicts a stack of 3D printed layers 322, each 3D printed layer having a layer height H and a layer width W. It is noted that in embodiments, the layer widths and/or layer heights may be different for two or more layers 322.

Referring to fig. 1a to 1c, the deposited filaments of 3D printable material result in a layer having a height H (and a width W). Layer 322 is deposited after layer 322, resulting in 3D article 1.

Fig. 1a to 1c generally show an embodiment of a method. Fig. 2a to 2f schematically depict some aspects in more detail, wherein core-shell 3D printing is also schematically illustrated.

A core-shell nozzle 502 may be applied, see fig. 2a, 2c and 2f, wherein different 3D printable materials 201 may be introduced to provide a 3D article 1 comprising 3D printable material 202, see fig. 2D.

FIG. 2a schematically depicts an embodiment printer nozzle 502, wherein the printer nozzle 502 comprises a core feed nozzle 5021 and a shell feed nozzle 5022 configured to provide a core-shell extrudate, wherein the core feed nozzle 5021 has a maximum core nozzle width w11 and a minimum core nozzle width w12, wherein the shell feed nozzle 5022 has a maximum shell nozzle width w21 and a minimum core nozzle width w 22. Here, w21 ═ w22, w21 > w11, w21 > w12, and w12 ═ w 11.

Fig. 2b schematically depicts an embodiment of a core-shell type filament 201, but such a schematic may also be used to show an embodiment of a core-shell type extrudate 321. The extrudate 321, which is here of the core-shell type, is also denoted as core-shell extrudate 1321. The dimensions may differ between the filaments and the extrudate.

The core is designated by reference numeral 321 and comprises a core material 1321. The shell is indicated by reference numeral 322 and comprises a shell material 1322. The illustrated filament 320 may be the printable 3D material 201, i.e., prior to deposition, or may refer to the extrudate 321 escaping from the nozzle. Thus, reference numerals 201 and 321 are both applied. In an embodiment, core-shell filament 320 or extrudate 321 may have a core diameter d1 selected from the range of 100 μm to 3000 μm. The shell thickness (d2) may be selected from the range of 100 μm to 2000 μm. Typically, the shell thickness is less than the core diameter.

As schematically depicted in fig. 2c, during at least part of the 3D printing stage, the extrudate 321 comprises a core-shell extrudate 1321, the core-shell extrudate 1321 comprising: core 2321 comprising core material 2011 and shell 2322 comprising shell material 2012, wherein core material 2011 and shell material 2012 comprise different thermoplastic materials.

Fig. 2c to 2d very schematically depict that, in an embodiment, the method may further comprise: the relative amounts of the first thermoplastic material 111 and the second thermoplastic 112 are controlled during the 3D printing stage. In fig. 2c, the core material 2011 downstream of the nozzle comprises the first thermoplastic material 111. From right to left, it appears that the 3D printing starts only from the first thermoplastic material. Thereafter, only the second thermoplastic material is deposited. Thereafter, the core-shell extrudate 1321 is provided and deposited as the core-shell 3D printing material 202. Thus, the method may further comprise: providing a core-shell extrudate 1321 at one or more times during the 3D printing stage; and providing an extrudate comprising one of the first thermoplastic material 111 and the second thermoplastic material 112 during one or more other time periods of the 3D printing stage. Fig. 2d schematically depicts some layers 202 of the second thermoplastic material 112, some core-shell layers 3322 with both the first thermoplastic material 111 and the second thermoplastic material (one of which consists of a core and the other of which consists of a shell), and some layers 202 of the second thermoplastic material 112. Fig. 2e schematically depicts the lowest layer 202 of the second thermoplastic material 112, two core-shell layers 3322 with both the first thermoplastic material 111 and the second thermoplastic material, one of which consists of a core and the other of which consists of a shell.

In top core-shell layer 3322, the first thermoplastic material 111 consists of core 2321 and the second thermoplastic material consists of shell 2322.

Thus, during one or more periods of the 3D printing phase, the core material 2011 comprises the first thermoplastic material 111 having the first glass transition temperature Tg1 of at most 0 ℃ and wherein the shell material 2012 comprises the second thermoplastic material having the second glass transition temperature Tg2 of at least 60 ℃, and/or during one or more periods of the 3D printing phase, the core material 2011 comprises the second thermoplastic material having the second glass transition temperature Tg2 of at least 60 ℃, and wherein the shell material 2012 comprises the first thermoplastic material 111 having the first glass transition temperature Tg1 of at most 0 ℃.

Fig. 2D and 2e also schematically depict embodiments of the 3D article 1 comprising the 3D printed material 202, wherein the 3D article 1 comprises a plurality of layers 322 of the 3D printed material 202, wherein the plurality of layers 322 comprises one or more core-shell layer portions 3322, wherein each of the core-shell layer portions 3322 comprises: a core 3321 comprising core material 3021 and a shell 3322 comprising shell material 3022, wherein core material 3021 and shell material 3022 comprise different thermoplastic materials selected from the group consisting of: a first thermoplastic material 111 as elastic material (having a first glass transition temperature Tg1 of at most 0 ℃) and a second thermoplastic material 112 (having a second glass transition temperature Tg2 of at least 60 ℃).

As shown in fig. 2c, the relative amounts of the first thermoplastic material 111 and the second thermoplastic material 112 varies with the length L3 of one or more of the one or more core-shell portions 3322. Such a length L3 may be a portion of a layer or may be the entire layer. Further, as shown in (fig. 2c, 2d, and 2 e), the plurality of layers 322 include one or more layer portions 3320 comprising one of the first thermoplastic material 111 and the second thermoplastic material 112.

During exposure to a liquid as solvent for the shell material, the thickness d22 may decrease and a smoothing effect may occur (see also fig. 3a to 3 c).

FIG. 2f schematically depicts an embodiment wherein the printer nozzle 502 comprises a core-feed nozzle 5021 and a shell-feed nozzle 5022 configured to provide a core-shell extrudate 1321, wherein the core-feed nozzle 5021 has a maximum core nozzle width w11 and a minimum core nozzle width w12, wherein the shell-feed nozzle 5022 has a maximum shell nozzle width w21 and a minimum core nozzle width w22, wherein w21 > w22, w21 > w11, w21 > w12, and wherein w12 ≧ w11 (where w12 ≧ w 11). This results in an extrudate having a deformed or extruded shape, unlike the extrudate schematically depicted in fig. 2 b. The distance between the nozzles may be a minimum of w52 and a maximum of w 51. It is noted that in such an embodiment, the shell thickness d2 of the extrudate downstream of the nozzle varies with the core, unlike the example in fig. 2b (assuming the embodiment of the extrudate of fig. 2b is to be depicted).

In fig. 3a, a cross-section of a structure consisting of a core-shell layer is schematically shown. The core and jacket materials may be selected as described herein. The surface is indicated with reference 205. At least part of the 3D printed material or its surface 205 is exposed to a solvent comprising a liquid resulting in a (smoother) surface structure schematically shown in fig. 3 b. Fig. 3c shows an example of a treated surface, and fig. 4 also shows this example.

Typically, the product is printed once, which means that the core material is one long fiber embedded in the shell matrix.

It is noted that d23 may be substantially zero μm in some portions between adjacent layer cores 3321. Thus, in some portions, adjacent layer cores 3321 may be in physical contact with each other (or may even form a single phase, as the core materials may be the same). Distance d23 may be formed by shell thickness d4 of one of the adjacent layer cores 3321 and d4 of the other of the adjacent layer cores 3321.

In fig. 4, the surface roughness of an object with a layer thickness of 800 μ M (i.e. reference mark W in fig. 2 e) measured using a DEKTAK 6M surface profiler before and after treatment with acetone is shown. In this figure, the surface roughness of the untreated objects (U1 and U2, relating to different surface portions) is about 200 μm. After treatment, the surface roughness represented by line a (i.e. after treatment with acetone) shows that the roughness is reduced to about 30 μm. Articles immersed in acetone liquid show little or no crack formation and essentially no delamination, nor deformation of the article. To obtain the object, polypropylene was used as the core material, and the cylinder was printed as the object using ABS jacket material. Acetone was used as a solvent for surface smoothing. Acetone is a solvent for ABS, however it does not dissolve PP. As shown in fig. 4 (and schematically in fig. 3b and 3c), during processing, the outer surface (ABS) is partially dissolved and smoothed. However, the inner part of the PP is not affected, since acetone is a non-solvent for PP. As a result, the backbone (PP) was not affected during the smoothing process, and no delamination or cracking was observed.

Fig. 5 schematically depicts an embodiment of a lamp or luminaire (indicated with reference numeral 2) comprising a light source 10 for generating light 11. The light may comprise a housing or a shade or other element, which may comprise or may be the 3D printed article 1.

The invention thus makes it possible to produce 3D structures with a band-shaped inner structure but with a relatively smooth surface having at least a much smaller roughness than the band-shaped inner structure.

The term "substantially" (such as "consisting essentially of.... times") herein is to be understood by those of skill in the art. The term "substantially" may also include embodiments having "completely," "entirely," etc. Thus, in embodiments, the adjective "substantially" may also be removed. Where applicable, the term "substantially" may also relate to 90% or more (such as 95% or more), particularly 99% or more, even more particularly 99.5% or more, including 100%. The term "comprising" also includes embodiments in which the term "comprises" means "consisting of. The term "and/or" particularly refers to one or more of the items mentioned before and after "and/or". For example, the phrase "item 1 and/or item 2" and similar phrases may refer to one or more of item 1 and object 2. The term "comprising" may mean "consisting of" in one embodiment, but may also mean "including at least the defined species and optionally one or more other species" in another embodiment.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The apparatus herein is described in the course of operation, among others. As will be clear to those skilled in the art, the present invention is not limited to the method of operation or the apparatus in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The present invention also provides a control system that may control a device or apparatus or system, or may perform a method or process as described herein. The present invention additionally provides a computer program product for controlling one or more controllable elements of an apparatus or device or system when run on a computer functionally coupled to or consisting of such apparatus or device or system.

The invention is also applicable to a device comprising one or more of the characterising features described in the description and/or shown in the attached drawings. The invention also applies to methods or processes comprising one or more of the characterising features described in the description and/or shown in the attached drawings.

To provide additional advantages, the various aspects discussed in this patent may be combined. Further, those skilled in the art will appreciate that embodiments may be combined, and that more than two embodiments may also be combined. Furthermore, some features may form the basis of one or more divisional applications.

Of course, one or more of the first (printable or printed) material and the second (printable or printed) material may comprise a filler, such as T for the material(s)_gOr T_mGlass and fibers without (with) influence.