FDM PRINTED LUMINAIRES WITH SURFACE TEXTURE

Abstract

A method for 3D printing a 3D item (10), the method comprising (i) providing 3D printable material (201) comprising particles (410) embedded in the 3D printable material (201), wherein the particles (410) have a longest dimension length (L1), a shortest dimension length (L2), and an aspect ratio AR defined as the ratio of the longest dimension length (L1) and the shortest dimension length (L2), and (ii) depositing during a printing stage 3D printable material (201) to provide the 3D item (10) to provide layers (230) of the 3D printed material (202) with a layer height (H), wherein: (i) 1<AR<4 and 1<H/L2<100.

Claims

1. A method for 3D printing a 3D item by means of Fused Deposition Modeling (FDM), the method comprising (i) providing 3D printable thermoplastic polymer material comprising particles embedded in the 3D printable thermoplastic polymer material, wherein the particles have a longest dimension length L1, a shortest dimension length L2, and an aspect ratio AR defined as the ratio of the longest dimension length L1 and the shortest dimension length L2, and (ii) depositing during a printing stage 3D printable thermoplastic polymer material to provide the 3D item to provide layers of the 3D printed thermoplastic polymer material with a layer height H, wherein 1≤AR≤4 and 1≤H/L2≤5.

2. The method according to claim 1, wherein the longest dimension length L1 is selected from the range of 5 μm-1 mm, wherein the layer height H is selected from the range of 50 μm-10 mm, and wherein the 3D printable thermoplastic polymer material (201) comprises in the range of 1-15 vol. % of the particles, relative to the total volume of the 3D printable thermoplastic polymer material.

3. The method according to claim 1, wherein 1≤AR≤2.

4. The method according to claim 1, wherein 2≤H/L2≤4.

5. The method according to claim 1, wherein the 3D printable thermoplastic polymer material may comprise one or more of acrylonitrile butadiene styrene, polystyrene, polycarbonate, polyethylenetelepthalate, polymethylmethacrylate, and copolymers of two or more of these.

6. The method according to claim 1, wherein the particles comprise one or more coated particles and uncoated particles, wherein the coating comprises one or more of silver and aluminum, and wherein the particles comprise one or more of mica particles, glass particles, and carbon particles, wherein the particles comprise elongated shaped particles having an aspect ratio AR larger than 1.

7. The method according to claim 1, wherein one or more of the 3D printable thermoplastic polymer material and the particles are transmissive for one or more wavelengths in the visible.

8. A 3D printed item obtainable by a method according to claim 1, wherein the 3D printed item comprises 3D printed thermoplastic polymer material, wherein the 3D printed thermoplastic polymer material comprises a thermoplastic material, wherein the 3D printed thermoplastic polymer material comprises particles embedded in the 3D printed thermoplastic polymer material, wherein the particles have a longest dimension length L1, a shortest dimension length L2, and an aspect ratio AR defined as the ratio of the longest dimension length L1 and the shortest dimension length L2, and wherein the 3D item comprises layers of the 3D printed material with a layer height (H), wherein 1≤AR≤4 and 1≤H/L2≤5.

9. The 3D printed item according to claim 8, wherein the longest dimension length L1 is selected from the range of 5 μm-1 mm, wherein the layer height (H) is selected from the range of 50 μm-10 mm, and wherein the 3D printed thermoplastic polymer material comprises in the range of 1-15 vol. % of the particles relative to the total volume of the 3D printed thermoplastic polymer material.

10. The 3D printed item according to claim 8, wherein 1≤AR≤2.

11. The 3D printed item according to claim 8, wherein 2≤H/L2≤4.

12. The 3D printed item according to claim 8, wherein the 3D printable thermoplastic polymer material comprises in the range of 1-5 vol. % of the particles, relative to the total volume of the 3D printable thermoplastic polymer material, and wherein the 3D printed thermoplastic polymer material may comprise one or more of acrylonitrile butadiene styrene, polystyrene, polycarbonate, polyethylenetelepthalate, polymethylmethacrylate, and copolymers of two or more of these, and wherein the particles comprise one or more coated particles and uncoated particles, wherein the coating comprises one or more of silver and aluminum, and wherein the particles comprise one or more of mica particles, glass particles, and carbon particles.

13. The 3D printed item according to claim 8, wherein the 3D printed item has a surface, wherein the surface comprises substructures with tops and bottoms, wherein the substructures comprise a plurality of layers with a top-top distance (d3) between adjacent tops, wherein d3/H≥10.

14. A lighting system comprising (a) a light source configured to generate light source light and (b) a 3D printed item according to claim 8, configured to transmit or reflect at least part of the light source light.

15. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] 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:

[0069] FIGS. 1a-1b schematically depict some general aspects of the 3D printer;

[0070] FIGS. 2a-2e schematically depict some aspects of the particles, such as flakes, that can be used herein;

[0071] FIGS. 3a-3b schematically depict some applications, including 3D printed items;

[0072] FIGS. 4a-4c schematically depict some further aspects of the invention; and

[0073] FIGS. 5a-5c show some pictures of 3D items that were printed.

[0074] The schematic drawings are not necessarily on scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0075] FIG. 1a schematically depicts some aspects of the 3D printer. Reference 500 indicates a 3D printer. Reference 530 indicates the functional unit configured to 3D print, especially FDM 3D printing; this reference may also indicate the 3D printing stage unit. Here, only the printer head for providing 3D printed thermoplastic polymer material, such as a FDM 3D printer head is schematically depicted. Reference 501 indicates the printer head. The 3D printer of the present invention may especially include a plurality of printer heads, though other embodiments are also possible. Reference 502 indicates a printer nozzle. The 3D printer of the present invention may especially include a plurality of printer nozzles, though other embodiments are also possible. Reference 320 indicates a filament of printable 3D printable thermoplastic polymer material (such as indicated above). For the sake of clarity, not all features of the 3D printer have been depicted, only those that are of especial relevance for the present invention (see further also below).

[0076] The 3D printer 500 is configured to generate a 3D item 10 by depositing on a receiver item 550, which may in embodiments at least temporarily be cooled, a plurality of filaments 320 wherein each filament 20 comprises 3D printable thermoplastic polymer material, such as having a melting point T.sub.m. The 3D printer 500 is configured to heat the filament material upstream of the printer nozzle 502. This may e.g. be done with a device comprising one or more of an extrusion and/or heating function. Such device is indicated with reference 573, and is arranged upstream from the printer nozzle 502 (i.e. in time before the filament material leaves the printer nozzle 502). The printer head 501 may (thus) include a liquefier or heater. Reference 201 indicates printable material. When deposited, this material is indicated as (3D) printed material, which is indicated with reference 202. Reference 1550 refers to a substrate. As indicated above, the term “receiver item” may refer to a printing platform, a print bed, a substrate, a support, a build plate, or a building platform, etc. Instead of the term “receiver item” also the term “substrate” may be used.

[0077] Reference 572 indicates a spool or roller with material, especially in the form of a wire. The 3D printer 500 transforms this in a filament or fiber 320 on the receiver item or on already deposited printed material. In general, the diameter of the filament downstream of the nozzle is reduced relative to the diameter of the filament upstream of the printer head. Hence, the printer nozzle is sometimes (also) indicated as extruder nozzle. Arranging filament by filament and filament on filament, a 3D item 10 may be formed. Reference 575 indicates the filament providing device, which here amongst others include the spool or roller and the driver wheels, indicated with reference 576.

[0078] Reference A indicates a longitudinal axis or filament axis.

[0079] Reference C schematically depicts a control system, such as especially a temperature control system, configured to control the temperature of the receiver item 550. The control system C may include a heater or may be functionally coupled to a heater, which may be able to heat the receiver item 550 to at least a temperature of 50° C., but especially up to a range of about 350° C., such as at least 200° C. The control system may especially be configured to control the 3D printing method, such as including controlling a layer height, etc.

[0080] FIG. 1b schematically depicts in 3D in more detail the printing of the 3D item 10 under construction. Here, in this schematic drawing the ends of the filaments 320 in a single plane are not interconnected, though in reality this may in embodiments be the case.

[0081] Hence, FIGS. 1a-1b schematically depict some aspects of a fused deposition modeling 3D printer 500, comprising (a) a first printer head 501 comprising a printer nozzle 502, (b) a filament providing device 575 configured to provide a filament 320 comprising 3D printable thermoplastic polymer material 201 to the first printer head 501, and optionally (c) a receiver item 550. In FIGS. 1a-1b, the first or second printable material or the first or second printed material are indicated with the general indications printable material 201 and printed material 202.

[0082] FIGS. 2a-2e schematically depict some aspects of the particles 410. Some particles 410 have a longest dimension A1 having a longest dimension length L1 and a shortest dimension A2 having a shortest dimension length L2. As can be seen from the drawings, the longest dimension length L1 and the shortest dimension length L2 have a first aspect ratio larger than 1. FIG. 2a schematically depicts a particle 410 in 3D, with the particle 410 having a length, height and width, with the particle (or flake) essentially having an elongated shape. Hence, the particle may have a further (minor or main) axis, herein indicated as further dimension A3. Essentially, the particles 410 are elongated thin particles, i.e. L2<L1, especially L2<<L1, and L2<L3, especially L2<<L3. L1 may e.g. be selected from the range of 1-500 μm; likewise L3 may be. L2 may e.g. be selected from the range of 0.1 μm-10 μm. Also L3 may e.g. be selected from the range of 0.1 μm-10 μm. However, L2 and/or L3 may also be longer, such as up to 5 mm, such as up to 1 mm, like up to 100 μm.

[0083] FIG. 2b schematically depicts a particle that has a less regular shape such as pieces of broken glass, with a virtual smallest rectangular parallelepiped enclosing the particle.

[0084] Note that the notations L1, L2, and L3, and A1, A2 and A3 are only used to indicate the axes and their lengths, and that the numbers are only used to distinguish the axis. Further, note that the particles are not essentially oval or rectangular parallelepiped. The particles may have any shape with at least a longest dimension substantially longer than a shortest dimension or minor axes, and which may essentially be flat. Especially, particles are used that are relatively regularly formed, i.e. the remaining volume of the fictive smallest rectangular parallelepiped enclosing the particle is small, such as less than 50%, like less than 25%, of the total volume.

[0085] FIG. 2c schematically depicts in cross-sectional view a particle 410 including a coating 412. The coating may comprise light reflective material. For instance, the coating may comprise a (white) metal oxide. In other embodiments, the coating may essentially consist of a metal, such as an Ag coating. In other embodiments the coatings may only be on one or both of the large surfaces and not on the thin side surfaces of the particles.

[0086] FIG. 2d schematically depicts a relatively irregularly shaped particle. The particulate material that is used may comprise e.g. small broken glass pieces. Hence, the particulate material that is embedded in the 3D printable thermoplastic polymer material or is embedded in the 3D printed thermoplastic polymer material may include a broad distribution of particles sizes. A rectangular parallelepiped can be used to define the (orthogonal) dimensions with lengths L1, L2 and L3.

[0087] Especially, particles with an irregular 3-D shape, a cylindrical shape (such as a short fiber), a spherical shape, are particularly relevant. FIG. 2e schematically depict cylindrical, spherical, and irregularly shaped particles.

[0088] FIG. 3a schematically depicts a lighting system 1000 comprising a) a light source 1010 configured to generate light source light 1011 and b) an object 10, such as defined above, configured to reflect or transmit at least part of said light source light 1011. Other functions of the object 10 may also be possible, such as a lamp shade, a wall of a device, etc.

[0089] For printing lamps and luminaires or other items, it may be desirable to create curved or angular shapes. Hence, amongst others we suggest herein the use of a curved or angular shapes receiver item 1550. The 3D printer can print on top of the surface of such shaped receiver item 1550, see FIG. 3b.

[0090] In injection molded parts surface finish and texture is realized by texturing the mold. As indicated above, in the case of FDM this need to be in a different way. For this purpose we suggest using various filler materials such as glass beads, fibers etc. In the case of essentially symmetric particles (beads, irregular shaped powders) to obtain the desired effect, the particle size may especially be in the range of 5 μm-500 μm. In the case of asymmetric particles (fibers, platelets) the largest dimension of 1 mm and aspect ratio of in the range 1-5 appeared to be the most desired range (in experiments that were executed). The most desirable particle concentration is found to be less than 15% volume (relative to the total volume of the 3D printed thermoplastic polymer material.

[0091] FIG. 4a schematically depicts a filament 320, such as when escaping from a printer nozzle (not depicted), which comprises 3D printable thermoplastic polymer material 201. The 3D printable thermoplastic polymer material comprise thermoplastic material 401 with particles 410 embedded therein.

[0092] FIG. 4b schematically depicts a 3D item 10, showing the ribbed structures (originating from the deposited filaments), having layer heights H and layer width W.

[0093] FIG. 4c schematically depicts a 3D printed item 10 with a substructure with a plurality of tops 13 and a plurality of bottoms 14. The top-top distance is indicated with reference d3.

[0094] A number of 3D printed items were generated

TABLE-US-00001 Series 1 Series 2 Series 3 1 ≤ AR ≤ 4 and AR ≥ 4 and 1 ≤ AR ≤ 4 and 1 ≤ H/L2 ≤ 5 H/L1 ≤ 1 5 ≤ H/L2 ≤ 100 Thermoplastic PC PC PC material Particle material glass glass glass Particle size (L1) 200 μm 140  30 μm Shortest dimension 200 μm 20 10 μm length (L2) Aspect ratio 1   7 3  Layer height (H) 0.4 mm; 0.6 mm; 0.10 mm 0.1 mm; 0.4 mm 0.8 mm Substructure — — d3/H = 8, 3.2 FIG. 5a  5b 5c

[0095] In series 1, it was observed that up to 0.8 mm rib thickness the ribbed structure becomes less visible. The beads help to hide the ribbed structure. In these embodiments 1≤AR≤4 and 1≤H/L2≤5 applies. In specific embodiments 1≤AR≤2 applies. In even more specific embodiments 1<AR<2 applies. In specific embodiments 1<H/L2<5 applies. In even more specific embodiments 2≤H/L2≤4 applies. In these ranges, the ribbed structure formation and properties may especially be controlled.

[0096] In series 2, cactus-type surfaces were obtained. Very rough surfaces layer where fibers get oriented and form needles.

[0097] In series 3, matt surfaces were obtained with a substructure.

[0098] The term “substantially” herein, such as “substantially consists”, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of”. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term “comprising” may in an embodiment refer to “consisting of” but may in another embodiment also refer to “containing at least the defined species and optionally one or more other species”.

[0099] 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.

[0100] The devices herein are amongst others described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation or devices in operation.

[0101] 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 “to 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.

[0102] The invention further applies to a device comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

[0103] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

[0104] It goes without saying that one or more of the first (printable or printed) material and second (printable or printed) material may contain fillers such as glass and fibers which do not have (to have) influence on the on T.sub.g or T.sub.m of the material(s).