Method of 3D printing using color mixing nozzle with multiple distribution elements

Abstract

The invention provides a printer head (501) for a 3D printer, the printer head (501) comprising n distribution elements (510), wherein n?2, a combination chamber (520), and a printer nozzle (502), wherein the combination chamber (520) is configured downstream of the distribution elements (510) and upstream of the printer nozzle (502), wherein each distribution element (510) comprise a flow-through chamber (511) with an inlet (512) and a plurality of k outlets (513) to the combination chamber (520), wherein k?4, wherein the outlets (513) of the distribution elements (510) are configured such that a plurality of outlets (513) of a distribution element (510) have outlets (513) of another distribution element (510) as nearest neighbors.

Claims

1. A method for 3D printing a 3D item, the method comprising: depositing m 3D printable materials to provide the 3D item comprising 3D printed material, wherein m?2, feeding the m 3D printable materials to at least m distribution elements of a printer head, and depositing the 3D printed material, wherein the printer head includes n distribution elements, wherein n?2, a combination chamber, and a printer nozzle, wherein the combination chamber is configured downstream of the distribution elements and upstream of the printer nozzle, wherein each distribution element comprises a flow-through chamber with an inlet for a 3D printable material and a plurality of k outlets to the combination chamber, wherein k?4, each distribution element being arranged to distribute the 3D printable material by the plurality of k outlets, wherein the outlets of the distribution elements are configured such that a plurality of outlets of a distribution element have outlets of another distribution element as nearest neighbors; and wherein m 3D printable materials comprise different thermoplastic materials or are 3D printable materials having different colors.

2. A method for 3D printing a 3D item, the method comprising: depositing m 3D printable materials to provide the 3D item comprising 3D printed material, wherein m?2, feeding the m 3D printable materials to at least m distribution elements of a printer head, and depositing the 3D printed material, wherein the printer head includes n distribution elements, wherein n?2, a combination chamber, and a printer nozzle, wherein the combination chamber is configured downstream of the distribution elements and upstream of the printer nozzle, wherein each distribution element comprises a flow-through chamber with an inlet for a 3D printable material and a plurality of k outlets to the combination chamber, wherein k?4, each distribution element being arranged to distribute the 3D printable material by the plurality of k outlets, wherein the outlets of the distribution elements are configured such that a plurality of outlets of a distribution element have outlets of another distribution element as nearest neighbors; and wherein the 3D printed material comprises plurality of domains originating from the m 3D printable materials, wherein the method comprises controlling the dimensions of the domains to have a largest width which is at maximum 120 ?m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIGS. 1a-1d schematically depict some general aspects of the 3D printer and of an embodiment of 3D printed material; FIG. 1d schematically depicts an embodiment; and

(3) FIGS. 2a-2i show some examples and results.

(4) The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) 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 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 321 indicates a filament of printable 3D printable 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).

(6) The 3D printer 500 is configured to generate a 3D item 1 by layer-wise depositing on a receiver item 550, which may in embodiments at least temporarily be cooled, a plurality of filaments 321 wherein each filament 310 comprises 3D printable material 201, such as having a melting point T.sub.m. The 3D printable material 201 may be deposited on a substrate 1550 (during the printing stage).

(7) 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.

(8) Reference 572 indicates a spool or roller with material, especially in the form of a wire, which may be indicated as filament 320. The 3D printer 500 transforms this in a filament 321 downstream of the printer nozzle which becomes a layer 322 on the receiver item or on already deposited printed material. In general, 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. Hence, the printer nozzle is sometimes (also) indicated as extruder nozzle. Arranging layer 322 by layer 322 and/or layer 322t on layer 322, a 3D item 1 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.

(9) Reference A indicates a longitudinal axis or filament axis.

(10) 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 which is 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.

(11) Alternatively or additionally, in embodiments the receiver plate may also be moveable 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 z axis (vertical). Hence, the control system may move the receiver plate in one or more of the x-direction, y-direction, and z-direction.

(12) Alternatively, the printer can have a head can also rotate during printing. Such a printer has an advantage that the printed material cannot rotate during printing.

(13) Layers are indicated with reference 322, and have a layer height H and a layer width W.

(14) Note that the 3D printable material is not necessarily provided as filament 320 to the printer head. Further, the filament 320 may also be produced in the 3D printer 500 from pieces of 3D printable material.

(15) FIG. 1b schematically depicts in 3D in more detail the printing of the 3D item 1 under construction. Here, in this schematic drawing the ends of the filaments 321 in a single plane are not interconnected, though in reality this may in embodiments be the case. Reference H indicates the height of a layer. Layers are indicated with reference 203. Here, the layers have an essentially circular cross-section. Often, however, they may be flattened, such as having an outer shape resembling a flat oval tube or flat oval duct (i.e. a circular shaped bar having a diameter that is compressed to have a smaller height than width, wherein the sides (defining the width) are (still) rounded).

(16) 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 321 comprising 3D printable 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. Directly downstream of the nozzle 502, the filament 321 with 3D printable material becomes, when deposited, layer 322 with 3D printed material 202.

(17) FIG. 1c schematically depicts a stack of 3D printed layers 322, each having a layer height H and a layer width W. Note that in embodiments the layer width and/or layer height may differ for two or more layers 322.

(18) Referring to FIGS. 1a-1c, the filament of 3D printable material that is deposited leads to a layer having a height H (and width W). Depositing layer 322 after layer 322, the 3D item 1 is generated.

(19) FIG. 1d schematically depicts a fused deposition modeling 3D printer 500 as define herein. A specific embodiment is depicted in FIG. 1c. Here, an embodiment is schematically depicted of the fused deposition modeling 3D printer 500, comprising a printer head 501 comprising a printer nozzle 502 as defined herein and a 3D printable material providing device 575 configured to provide 3D printable material 201 to the printer head 501, wherein the fused deposition modeling 3D printer 500 is configured to provide said 3D printable material 201 to a substrate 1550. Here, the embodiment clearly shows an embodiment wherein the 3D printable material providing device 575 is configured to provide n 3D printable materials 201 to the n distribution elements 510, respectively. In this example, n=2. Note that it may also be possible to provide two or more different 3D printable materials to a single distribution element; this might be done for two or more of the n distribution elements; for the schematically drawings of the distribution elements, see below.

(20) In embodiments, control system C may be configured to control the relative volumes of 3D printable material that enter the combination chamber.

(21) FIG. 2a schematically depicts an embodiment of a printer head 501 for a 3D printer. Here, a cross-section is shown in perspective. The printer head 501 comprises n distribution elements 510. Here, n=2.

(22) The printer head 501 comprises further a combination chamber 520, and a printer nozzle 502, wherein the combination chamber 520, which is configured downstream of the distribution elements 510 and upstream of the printer nozzle 502.

(23) Each distribution element 510 comprises a flow-through chamber 511 with an inlet 512 (for 3D printable material 201). Further, each flow-through chamber 511 comprises a plurality of k outlets 513 to the combination chamber 520. As schematically shown, the outlets 513 of the distribution elements 510 are configured such that a plurality of outlets 513 of a distribution element 510 have outlets 513 of another distribution element 510 as nearest neighbors. As is also shown, this may apply to a subset of all outlets 513, but not to all. To distinguish the outlets of the different distribution element 510 are indicated with references 513a and 513b.

(24) Note that a distribution chamber may also have more than one inlet 512 (embodiment with a plurality of inlets 512 for a single distribution element is not depicted). For instance, the same or different 3D printable materials may be provided to a single distribution chamber via different inlets 512.

(25) Reference 525 indicates a central part of an outlet area 521 comprising the outlets 513 (see also FIG. 2h).

(26) More in general, FIG. 2a schematically depicts a material combination element 5001 especially suitable for combining (different types of) 3D printable materials, comprising n distribution elements 510, wherein n?2, a combination chamber 520, and an opening 5002, such as a nozzle, wherein the combination chamber 520 is configured downstream of the distribution elements 510 and upstream of the opening 5002, wherein each distribution element 510 comprise a flow-through chamber 511 with an inlet 512 (for 3D printable material 201) and a plurality of k outlets 513 to the combination chamber 520, wherein k?4, wherein the outlets 513 of the distribution elements 510 are configured such that a plurality of outlets 513 of a distribution element 510 have outlets 513 of another distribution element 510 as nearest neighbors.

(27) FIG. 2b schematically depicts a top view, in perspective, of the embodiment or a variant thereon of the embodiment schematically depicted in FIG. 2a.

(28) FIGS. 2c and 2d schematically depict a bottom view, as well as a side view, in perspective, respectively, showing embodiments and variants wherein the outlets 513 of the distribution elements 510 are configured regularly distributed over an outlet area 521, wherein the outlet area 521 is configured upstream of at least part of the combination chamber 520. As schematically shown a plurality, here all outlets 513, of a distribution element 510 have outlets 513 of another distribution element 510 as nearest neighbors. This does not exclude that some may also have an outlet of the same distribution element as (other) nearest neighbor.

(29) FIG. 2e schematically depicts another embodiment, wherein the outlets 513 of the n distribution elements 510 are configured regularly distributed over an ellipse-shaped outlet area 521. Here, the outlet area 521 is ring-shaped. Further, this figure also shows an embodiment that further comprises a conically shaped element 522 having a base 523 configured between or upstream of the ellipse-shaped outlet area 521 and an apex 524 directed to the nozzle 502.

(30) FIG. 2 schematically depicts an embodiment wherein the outlets 513 of the n distribution elements 510 are configured regularly distributed about the periphery of a surface or outlet area 521 defined by a circle, oval, or polygonal shaped outlet area 521, here a circle.

(31) FIG. 2f depicts in a photograph an embodiment of 3D item 1, though more precisely this may be a cross-section of a non-decompressed layer 203. The item 1 comprises 3D printed material 202. The 3D item 1 comprising layers of 3D printed material, as schematically shown in FIGS. 1a-1c. The layers 203 especially comprise a first 3D printed material 202, which especially comprises a (first) thermoplastic material. Further, the layers 203 comprise a second 3D printed material 202, which also especially comprises thermoplastic material (second thermoplastic material). The layers further comprise domains 212 of the first or the second thermoplastic material. Actually, both the first 3D printed material and the second 3D printed material are available in domains. The domains 212 of the first and second thermoplastic material are alternately arranged around a longitudinal axis of the layer. The longitudinal axis of the layer is the longitudinal axis or filament axis indicated with reference A in FIG. 1b. At an outer surface of the layer, the domains 212 have a largest width w1 of 200 ?m or less. As shown in FIG. 2e it may be arbitrary whether this dimension is indicated as width or height. The cross-sectional length or depth may be about the radius but may also be smaller. The length, i.e. along a perpendicular to the plane of drawing, may be much longer than the largest width w1 which is at maximum 200 ?m. Especially, the domains 212 have a largest width w1 which is at maximum 120 ?m.

(32) The first thermoplastic material and the second thermoplastic material may be the same or different materials. The domains 212 may have two or more different colors. Together, the domains in the layers may provide an overall (color) impression, averaged over the domains in the layers.

(33) FIG. 2f (right) schematically depicts an embodiment wherein the relative volumes of 3D printable material that entered the combination chamber were essentially the same. The resulting different domains are equally distributed. However, herein also embodiments are described wherein the relative volumes are controlled to vary the properties of the 3D printed material, see e.g. FIG. 2g.

(34) FIG. 2g shows a photograph wherein a nearly stepless transition from one color to another color is shown. This behavior is shown over the entire diameter; this is not possible with prior art FDM methods. FIG. 2f also shows a schematic representation. Here, Above figure is maybe clearer? Here, two (n=2) distribution elements may have been applied, with each 9 (k=9) outlets, leading to 2*9 domains. The width W1 of the domains may be about 200 ?m or smaller, such as 120 ?m or smaller, like 100 ?m or smaller, such as 60 ?m or smaller. However, this may depend upon the application. The width of the domains may in principle differ. This is indicated with references w11 and w2.

(35) Hence, especially printing conditions and/or printer conditions are chosen such that w1 is equal to or smaller than 200 ?m, such as equal to or smaller than 120 ?m, like especially equal to or smaller than 100 ?m.

(36) FIG. 2 also shows that the 3D printed material may comprise a plurality of first domains and a plurality of second domains (when using the herein described method and/or printer head with different 3D printable materials).

(37) FIG. 2h schematically depicts an embodiment wherein a plurality of combination elements 5001 may be combined. For instance, at least two combination elements 5001 may be used as feed for a printer head 501, which may in essence also comprise a combination element 5001. Note that the flow-through chamber 520 of printer head or of the most downstream configured combination element may e.g. be configured as a ring. In such embodiment, the left and right part in this schematic drawing may communicate. As here two combination elements 5001 are configured upstream of this flow-through chamber 520 of printer head or of the most downstream configured combination element, there may be a plurality of such flow-through chamber 520, configured around the central flow-through chamber.

(38) Hence, FIG. 2h schematically shows an embodiment of a combination of passive mixing elements. Upstream of the printer head, more precisely upstream of one or more distribution elements, another printer head is configured, which may be used to provide to a distribution element of the downstream printer head 3D printable material that is already a combination of (3D) printable materials. Such configuration may be applied to one or more of the distribution elements of the downstream printer head. Hence, FIG. 2h schematically shows an embodiment of a fused deposition modeling 3D printer 500 comprising two at least two printer heads 501, wherein the printer nozzle 502 of a first printer head 501 is configured upstream of the inlet 512 of a distribution elements 510 of a second printer head 510.

(39) FIG. 2h also shows the equivalent diameter D1 of the nozzle 502, with the nozzle (opening) having an area of A1. Likewise, the outlets 513 have an equivalent diameter D2, with the outlet (opening) having an area A2. The diameters and areas may differ for two or more of the outlets 513, but may also be all the same within the printer head. The squeeze factor SF may be defined as the ((area of all the holes in the mixing chamber)/(area of the nozzle)=(A2*n*k)/(A1), where A2 is the area of a single outlet in the mixing chamber (assuming the area A2 is the same for all outlets).

(40) FIG. 2i schematically depicts an outlet area 521, having a central part 525. Especially for a plurality of the outlets 513 configured most remote from the central part 525 applies that a plurality of outlets 513 of a distribution element have outlets 513 of another distribution element as nearest neighbors. Here, again an example with two distribution elements is applied, wherein the different outlets 513 of the different distribution elements are indicated with references 513a and 513b, respectively. With such embodiments, the distribution of the domains such as shown in FIG. 2e may be obtained, see also the embodiment of FIG. 2d, wherein all outlets 513 are alternatingly configured in a ring-shaped outlet area.

(41) 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.

(42) 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.

(43) 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.

(44) 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.

(45) The invention also provides a control system that may control the apparatus or device or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the apparatus or device or system, controls one or more controllable elements of such apparatus or device or system.

(46) 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.

(47) 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.

(48) 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).