Adjustable nozzle for additive manufacturing

Abstract

Adjustable nozzle arrangement for an additive manufacturing system, comprising the following: a nozzle (10) and an angled piece (9), wherein the angled piece (9) is in fluid communication with an outlet of an extruder (3) of the additive manufacturing system and the angled piece (9) has a first bending angle; characterized by that the nozzle (10) is functionally coupled to the angle piece (9) via a first flange (13) and a second flange (14), that the nozzle (10) has a second bending angle; and that the first flange (13) and the second flange (14) are rotatable relative to each other.

Description

AREA OF INVENTION

[0001] The present invention relates generally to automatic additive manufacturing systems, and in particular to nozzles for the automatic deposition of a melt for use therein. BACKGROUND OF THE INVENTION

[0002] Additive manufacturing technology (three-dimensional (3D) printing) is developing rapidly, sparking interest in the development of new, improved materials and more powerful automated machines for the automatic melting of materials to produce any desired three-dimensional shape. There is also a growing interest in increasing the size of the molded parts.

[0003] The most commonly used materials belong to the thermoplastic family. The automated systems typically employed include an extruder head spatially controlled by multi-axis positioners with a defined workspace, and a fully integrated automated material feed system.

[0004] Additive manufacturing systems typically use a layer-based process to build any desired three-dimensional part. The machine takes data directly from CAD (Computer-Aided Design) files and creates functional parts by extruding and depositing molten material layer by layer from its extruder nozzle, enabling the production of even highly complex parts.

[0005] Specifically, each new layer is applied to the previous layer and has a cross-shaped cross-section. The size and shape of these sections depend on several key parameters, such as material type, material temperature, extruder output, machine feed rate, and others. This multi-layer manufacturing process aims to produce parts that are ultimately dimensionally stable and possess the desired strength and durability.

[0006] US patent application US 2019 / 091929 A1 discloses a nozzle for an additive manufacturing system with an alignable nozzle arrangement.

[0007] The most common machine configuration for large-area systems is a Cartesian 3-axis machine with a portal structure and a vertical ram to which an extruder end effector is attached.

[0008] The extruder assembly typically consists of a motorized screw extruder with material feed mechanism, suitable heating elements, and an exit die, which is usually arranged coaxially to the screw (linear arrangement). The entire assembly is generally bolted parallel or coaxially to the machine's vertical ram, so that the extruder die's centerline is vertical and the material flows downwards.

[0009] By combining full CNC control of the nozzle movement with all operating parameters of the extruder, current systems enable the creation of quite complex shapes and impressive part sizes, even when the output nozzle remains strictly vertical.

[0010] However, these systems still have some limitations, particularly in critical areas where the structure faces the problem that the walls tend to collapse under their own weight while they are not yet fully cured.

[0011] In light of the above, embodiments of the present invention provide a device and a method, described herein in a multitude of alternative embodiments, to overcome or reduce the problems existing in the prior art. These and other advantages of the embodiments of the present invention, as well as additional inventive features, will become apparent from the description of the embodiments of the invention provided herein. BRIEF SUMMARY OF THE INVENTION

[0012] It has been discovered that for the aforementioned problematic areas known to the skilled person, noticeable improvements can be achieved by locally applying a laying strategy that requires a special nozzle alignment.

[0013] It was also discovered that the ability to change the orientation of the output nozzle is an effective additional means of better controlling the desired bead shape during the laying process.

[0014] To overcome the problems described above and others, there is a need for an adjustable nozzle in the field of large-area gantry systems. With such an adjustable nozzle, part programs can be created where an operator can assign the optimal nozzle centerline orientation as an option to a standard vertical position.

[0015] Embodiments of the present invention provide such methods and devices for aligning the extruder outlet nozzle with respect to the vertical Z-axis of the machine ram (or the extruder centerline).

[0016] Preferably, at least one embodiment of the present invention is fully programmable, and even more preferably, such programmability forms an integral part of the CNC-controlled laying process.

[0017] Other aspects, objectives and advantages of the invention will become clearer from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which form part of the description, illustrate various aspects of the present invention and, together with the description, serve to explain the principles of the invention. The drawings show: Fig. Figure I is a perspective view of a large-area additive manufacturing machine to which embodiments of the present invention are particularly applicable, although they are not limited to it; Fig. 2 is an isometric view of an embodiment of a device constructed according to the teaching of the present invention; Fig. Figure 3 is an enlarged isometric view of a nozzle part of the device of Fig. 2; Fig. Figures 4-6 are isometric illustrations showing different nozzle orientations for the nozzle of the device. Fig. 2; Fig. 7 is an isometric view of another embodiment of a device constructed according to the teaching of the present invention; Fig. Figure 8 is an enlarged isometric view of a nozzle section of the device of Fig. 7; and Fig. Figure 9 is an isometric view of a further embodiment of a device according to the teachings of the present invention.

[0019] Although the invention is described in connection with certain preferred embodiments, there is no intention to limit it to these embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0020] Fig. Figure 1 shows a schematic representation of a typical large-area additive manufacturing (AM) system with a Cartesian gantry machine featuring a horizontal cross rail (gantry) 1 and a vertical ram 2, which is particularly well suited for embodiments of the present invention. In its basic configuration, the AM machine moves along the linear axes X, Y, and Z, and the extruder 3 is attached to the machine ram 2. It should be noted, however, that while embodiments of the present invention are described below with regard to this exemplary operating environment, it is not intended to limit the scope of the invention to these. Indeed, the description of the examples that follow should be understood as examples and not as limitations.

[0021] In the embodiment shown, the extruder 3 uses a motorized screw 4 which is connected to an automatic material feeding system 5, wherein the exit nozzle 6 is arranged coaxially to the extruder screw 4 and has a center line 7 parallel to the vertical Z-axis.

[0022] Fig. Figure 2 shows an embodiment of the alignable nozzle arrangement according to the present invention, and Fig. Figure 3 is an enlarged detail view of the nozzle assembly. The nozzle assembly comprises an extruder adapter 8, an intermediate elbow 9, and a print outlet nozzle 10. The adapter 8 is connected to the extruder and receives the liquid (molten) printing material. The elbow 9 is connected to the adapter 8 via the rotatable, adjustable flanges 11 and 12, which can be rotated relative to each other by an angle C between 0 and 360 degrees. Similarly, the nozzle 10 is connected to the elbow 9 by rotatable, adjustable flanges 13 and 14, which can be rotated by an angle A between 0 and 360 degrees. It should be noted that the above-mentioned suitable heating media and insulating jackets are not shown in order to better illustrate the flange connections 11, 12, 13 and 14 and the angular bends for the adapter 8, the elbow 9 and the nozzle 10 of the illustrated embodiment of the present invention.However, depending on the type of printing material used, suitable heating elements and insulating jackets can be provided for these components to prevent a temperature drop that could lead to an increase in the viscosity of the flowing molten printing material, as is known in the art.

[0023] Flanges 11 and 12 are arranged horizontally and perpendicular to the vertical center of the extruder (7). The elbow 9 has a 45-degree bend between its inlet and outlet lines. In the present embodiment, where the elbow 9 is used, flanges 11 and 12 are therefore oriented at a 45-degree angle to flanges 13 and 14. In the illustrated embodiment, the outlet nozzle 10 also has a 45-degree bend between its inner inlet and outlet lines.

[0024] The connection between flanges 11 and 12, as well as 13 and 14, includes a bearing that allows relative rotation between the two flanges, and a rotating seal capable of withstanding the material pressure and temperature. These components are commercially available and are not shown here.

[0025] As a result of the component arrangement described above, the centerline of the outlet line of the outlet nozzle 10 can assume any desired angle with respect to the vertical Z-axis of the machine in both the XZ and YZ planes by changing the relative angle C between flanges 11 and 12, or alternatively, the angle A between flanges 13 and 14. In other words, by rotating A and C, two additional polar degrees of freedom are introduced for the outlet of the nozzle 10, so that the nozzle 10 can discharge the molten material in a direction that leads to any point on a spherical surface centered at the end of the machine punch.

[0026] Fig. Figures 4-6 illustrate three such orientations, namely 0 degrees from the vertical ( Fig. 4), 45 degrees from the vertical ( Fig. 5) and 90 degrees from the vertical ( Fig. 6).

[0027] As explained in more detail below, the A and / or C angles can be adjusted manually or by motor and fully CNC control. In one embodiment, the adjustment range of the A-axis is limited to 0-180 degrees.

[0028] The in the Fig. 2 and Fig. The arrangement shown in Figure 3 offers simple and easy accessibility and compactness of the drive mechanism (not shown) combined with an easier way to accommodate the required bearings and seals between the connecting flanges 11 and / or 12, or 13 and 14.

[0029] Fig. 7 and Fig. Figure 8 shows an alternative embodiment of the present invention, in which the angle between the flanges 11, 12 and 13, 14 is 90 degrees relative to the 45 degrees of the Fig. 2 and Fig. 3 is enlarged. In this embodiment, both the angled piece 15 and the nozzle 16 have a 90-degree bend between their inner inlet and outlet lines.

[0030] Fig. Figure 9 shows a further alternative embodiment of the present invention, in which the angled piece 9 is connected to the outlet of the extruder and, via flanges 13 and 14, to the nozzle 10 to provide the single angle of rotation A. Additionally, in a further embodiment, rotation by angle C is achieved by rotating the entire extruder assembly and the nozzle about the extruder centerline 7 by means of a bearing 18 arranged between the machine ram 2 and the extruder body 3 by means of supports 17 and 19.

[0031] In all embodiments described above, the setting of angles C and / or A can be adjusted manually and locked in any desired position, or it can be motorized and CNC-controlled.

[0032] From the above description, it is evident how the alignable nozzle system according to the present invention achieves the application range and provides the desired additional degree of freedom to improve the overall system performance.

[0033] Preferred embodiments of the present invention are described herein, including the best embodiments of the invention known to the inventors. Variations of these preferred embodiments may become apparent to those skilled in the art upon reading the foregoing description. The inventors assume that experienced professionals will make appropriate use of such variations, and the inventors intend to implement the invention in a manner other than that described herein.

[0034] The use of the terms "a" and "an," as well as "the" and similar designations in connection with the description of the invention (particularly in connection with the following claims), refers to both the singular and the plural unless otherwise specified or clearly contradicted by the context. The terms "comprising," "with," "including," and "containing" are to be understood as open terms (i.e., in the sense of "including but not limited to") unless otherwise specified. The enumeration of value ranges serves merely as a shorthand for each individual value falling within the range unless otherwise specified herein, and each individual value is included in the specification as if it were listed here individually. All methods described herein may be carried out in any suitable order unless otherwise specified herein or clearly contradicted by the context.The use of examples or illustrative expressions (e.g., "like") serves only to better clarify the invention and does not constitute a limitation of the scope of the invention unless otherwise stated. No wording in the description should be interpreted as implying that an unclaimed element is essential for the embodiment of the invention. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2019 / 091929 A1

[0006]

Claims

[1] Adjustable nozzle arrangement for an additive manufacturing system comprising the following: a nozzle (10) and an angled piece (9), wherein the angled piece (9) is in fluid communication with an outlet of an extruder (3) of the additive manufacturing system and the angled piece (9) has a first bending angle; characterized by , that the nozzle (10) is functionally coupled to the angle piece (9) via a first flange (13) and a second flange (14), that the nozzle (10) has a second bending angle; and that the first flange (13) and the second flange (14) are rotatable relative to each other. [2] Adjustable nozzle arrangement according to claim 1, wherein the first angle and the second angle are equal. [3] Adjustable nozzle arrangement according to claim 2, wherein the first angle and the second angle are 45 degrees, or wherein the first angle and the second angle are 90 degrees. [4] Adjustable nozzle arrangement according to claim 1, further comprising: a third flange (11) and a fourth flange (12) which are rotatable relative to each other, wherein the third flange (11) and the fourth flange (12) are arranged such that they rotate the angle piece. [5] Alignable nozzle arrangement according to claim 4, wherein the third flange (11) and the fourth flange (12) are arranged between the elbow (9) and the outlet of the extruder (3) of the additive manufacturing system, wherein optionally the alignable nozzle arrangement further comprises an extruder adapter (8) which connects the outlet of the extruder (3) to the elbow via the third flange (11) and the fourth flange (12). [6] Alignable nozzle arrangement according to claim 4, wherein the third flange (11) and the fourth flange (12) are arranged between the extruder (3) and a tool slide (2) of the additive manufacturing system. [7] Adjustable nozzle arrangement according to claim 4, wherein the third flange (11) and the fourth flange (12) are manually rotatable relative to each other, or wherein the rotation of the third flange (11) and the fourth flange (12) relative to each other is motorized. [8] Adjustable nozzle arrangement according to claim 1, wherein the first flange (13) and the second flange (14) are manually rotatable relative to each other, or wherein the rotation of the first flange (13) and the second flange (14) relative to each other is motorized. [9] Adjustable nozzle arrangement according to claim 1 further comprising a heating device which is in thermal contact with the angle piece (9) and / or the nozzle (10). [10] Adjustable nozzle arrangement according to claim 9, wherein the heating device is arranged in thermal connection with both the angle piece (9) and the nozzle (10). [11] Adjustable nozzle arrangement according to claim 9 further comprising an insulating jacket surrounding the heating device. [12] An additive manufacturing (AM) system comprising the following: - a Cartesian portal machine (1) with a horizontal cross rail (1), - a vertical tool slide (2), - an extruder (3) mounted on the vertical tool slide (2) with a motorized screw connected to an automatic material feeding system, and - an adjustable nozzle according to claim 1. [13] AM system according to claim 12, further comprising: a third flange (11) and a fourth flange (12) which are rotatable relative to each other and are arranged between the angled piece (9) and the outlet of the extruder (3); and wherein the third flange (11) and the fourth flange (12) are arranged such that they rotate the angle piece (9), where optionally the AM system further includes an extruder adapter (8) which fluidically connects the outlet of the extruder (3) through the third flange (11) and the fourth flange (12) to the angle piece (9). [14] AM system according to claim 12, wherein the first flange (13) and the second flange (14) are either manually rotatable relative to each other or wherein the rotation of the first flange (13) and the second flange (14) relative to each other is motorized. [15] The AM system according to claim 12 further comprises a heater which is in thermal contact with at least one of the two parts, the angle piece (9) and the nozzle (10).

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