3D printer print head with infinitely rotating nozzle and sealless design

Abstract

The rotating print head combines rapid material deposition with high precision in intricate details. It enables fast printing of large volumes thanks to a large nozzle, while ensuring increased finesse in delicate corners and contours. This flexibility is particularly useful for printing technical materials in high-temperature environments, guaranteeing fast and stable extrusion. Compatible with standard and high-temperature 3D printers, it adapts to a variety of materials and applications. Post-processing of the G-code file dynamically adjusts the nozzle rotation and print width variations to optimize movement and improve the final part quality. Figure for the Summary: Fig. 1

Description

Title of the invention: Print head for 3D printer with infinitely rotating nozzle and sealless sealing. Field of the invention

[0001] This invention is in the field of additive manufacturing, more particularly in the field of 3D printers with fused deposition modeling technology and print heads equipped with rotating nozzles allowing precise control of material flow. Prior art

[0002] Several print head solutions for 3D printers have been proposed in the prior art. For example, US patent 2017 / 0320267 A1 describes a print head using polymer seals for nozzle sealing. However, the use of polymer materials for the seals has limitations in terms of heat resistance, which restricts the application of this technology in high-temperature environments. These seals can also deform under prolonged thermal stress, compromising the print head's sealing.

[0003] EP patent 3 117 982 B1 proposes a variable-size nozzle capable of adjusting the extrusion width during printing. While this approach offers interesting flexibility, it introduces additional mechanical complexity that makes its manufacture and integration into standard systems more expensive, cumbersome, and technically demanding.

[0004] French patent FR2410858 describes a print head incorporating a sealing system achieved by pressure between two polished surfaces held in contact by a spring. This design ensures a seal under standard and high-temperature operating conditions. However, limitations remain, notably a risk of leakage when the extrusion nozzle becomes clogged or when the material flow rate delivered by the extruder becomes excessive. In such cases, the internal pressure in the nozzle can exceed the holding force exerted by the spring, thus compromising the sealing of the device.

[0005] Thus, despite these advances, there remains a need for a print head offering infinite nozzle rotation, with a leak-proof sealing mechanism in both high-temperature and standard environments, and a simplified design compatible with both standard and high-temperature 3D printers. Technical problems to be solved

[0006] The proposed print head must meet several requirements to be usable in standard and high-temperature environments. In particular, it is essential The print head should be compact and lightweight to minimize the load on the printer's movement system and avoid compromising printing accuracy and speed. Furthermore, the use of polymer seals is discouraged, as they do not adequately withstand the thermal stresses of high-temperature technical materials. Sealing must be achieved through robust mechanical solutions, ensuring increased durability and reliability under high pressure or high temperature conditions.

[0007] The objective of the invention is to provide an infinitely rotating print head that maintains a simple, lightweight and compact design, while offering compatibility with standard and high-temperature 3D printers, without risk of material leakage from the sealing system. Presentation of the invention

[0008] The present invention relates to a print head for a 3D printer equipped with an infinitely rotating nozzle. This print head combines large volume material deposition while maintaining printing fineness to print details of the part. This print head makes it possible to significantly reduce printing times while maintaining the detail and fineness of the part to be printed. The nozzle rotation is driven by a stepper motor or other, allowing integration into most 3D printer controllers, whether standard or high-temperature models. The invention proposes an innovative sealing system for moving parts, distinct from traditional sealing mechanisms. In this configuration, a metal tube, fixed to the nozzle's rotation, ensures continuity between the nozzle's hot zone and a cooled zone, either air-cooled or liquid-cooled. This device allows the filament of material to enter the tube while remaining cold, then progress to the heated zone where it transitions from a solid to a molten state. Thanks to this gradual transition, sealing is guaranteed without the need for additional gaskets, thus eliminating the risk of leakage associated with temperature variations and pressure stresses.

[0009] This print head can be easily adapted to different extruders and works with standard software thanks to post-processing of the G-code file. Detailed description of the invention

[0010] The print head comprises:

[0011] Rotation motor: A stepper motor or other motor allowing infinite rotation of the nozzle. This motor is compatible with standard and high-temperature 3D printer controllers, ensuring broad compatibility.

[0012] Printing capacity: This printhead combines the advantages of conventional printheads by offering both: a. Fast printing, similar to that obtained with a head equipped with a large nozzle, which allows large volumes of material to be deposited in a short time. b. High print quality, comparable to that of a print head with a small nozzle, thanks to the controlled rotation of the nozzle and the precise adjustment of its movements, especially in corners and complex areas.

[0013] Sealing System: The sealing system of the invention is distinguished by its intrinsic nature, eliminating the need for traditional sealing components. The seal is ensured by the specific design of the rotating nozzle subassembly, which begins in a cooled zone at the top, where the filament is kept in a solid state, and then extends to a hot zone at the bottom, where the filament transitions to a liquid or paste-like state. These two zones of the rotating nozzle subassembly are connected by a low-thermal-conductivity metal section, ensuring effective thermal insulation between the two regions. Cooling of the upper part of the rotary nozzle subassembly is achieved by conduction between the rotating body and the cold zone of the print head. This cooling can be achieved through various means, including air, liquid, or any other method of heat dissipation. This principle prevents leaks by keeping the filament in a solid state as it enters the tube until it reaches the melting zone. The lower part of the rotating nozzle sub-assembly is heated by conduction, via its contact with the heating element, allowing the material to pass into a molten state in this area.

[0014] Rotation system: Continuous rotation is made possible by a gear system that drives a rotating body mounted on bearings, into which a rotating nozzle subassembly is screwed. A pinion offsets the axis of rotation, shifting the rotation motor to a cooler area. The rotating part guided by the bearings is located in an area cooled by air, water, or other means.

[0015] Rotating Nozzle: The rotary nozzle of the print head can adopt various shapes, such as a rounded rectangle, a rectangle, an oblong, or any other shape depending on the printing requirements. This nozzle is directly driven by the rotary gear, ensuring synchronization with the movement of the print head axis. Furthermore, the nozzle is easily interchangeable, allowing for quick and easy maintenance. It is screwed into the rotating body, which guarantees precise positioning during replacement.

[0016] Adaptability: The head is adaptable to various types of extruders. It is compatible with standard or high-temperature printers, thus offering great flexibility for the user.

[0017] Software: The print head operates with standard slicing software, which may be open source or proprietary. This standard software generates the displacement calculations for prints using a large nozzle the size of the large length of the rotating nozzle.

[0018] After the initial generation of the path by this standard software, a script or complementary software is used to analyze the generated paths and add to them: a. Additional movements and nozzle axis rotations to optimize printing in all corners and angles of the basic path while maintaining fine printing in corners, thanks to a precise nozzle rotation control mechanism. b. A nozzle axis rotation for all linear movements, allowing precise control of nozzle orientation and optimization of printing performance, providing in all areas where possible a high printing flow rate, identical to that of the standard software with the large nozzle. c. The invention incorporates a nozzle axis rotation feature designed to automatically adjust to movements requiring a reduction in print width, in order to better match the geometry of the printed part. Instead of positioning the nozzle perpendicular to the direction of travel, the nozzle is rotated at a specific angle, thus reducing the effective print width. This controlled rotation provides greater precision in areas requiring thin walls or dimensional adjustments, ensuring better adaptation to the contours and complex features of the part. This mechanism allows for more detailed and precise printing without requiring a nozzle change. d. The complementary software performs what is called in 3D printing jargon post-processing The attached drawings illustrate the invention#:

[0019] Fig. 1 shows an overall perspective view of the liquid-cooled rotating 3D printing head, in the case of use on a filament head using a commercially available standard extruder Figure 2 shows an overview from below, in perspective, of the rotating 3D printing head with liquid cooling. Figure 3 shows a cross-sectional view along the XZ plane of the rotating 3D printing head. Figure 4 shows an exploded view of a Nozzle Subassembly mounted on the rotating body Figure 5 illustrates the operating principles of the post-processing software: on the left, a standard path generated by standard software; the right-hand side represents the modifications to the paths made by the post-processing software. Figure 6 shows an example of a path containing variations in print width. The top part shows a standard path generated by standard software containing variations in print width; the bottom part shows the modifications to the paths made by the post-processing software to adapt the angular position of the rotating nozzle to the required print width. Description of the figures

[0020] [Fig.1]: Perspective overview of the rotating 3D printing head with liquid cooling. Main Heating Body (1): Central part of the head which heats the material for extrusion. Rotary Nozzle Sub-Assembly (6): Nozzle that can take different shapes (rectangular, oblong, etc.) and is interchangeable. Heating Cartridge (7): Cartridge heating the Main Heating Body Coolant Inlet / Outlet (9): Coolant inlets and outlets allowing cooling of the cold zone of the head. Support Body (10): Body supporting the various components. Cold Zone of the Head (13): Upper part of the head, thermally insulated from the Main Heating Body. Nozzle Rotation Drive Motor (15): Motor that drives the rotating nozzle, located in a cold area to avoid the effects of heat. Extrusion drive motor (16): Motor that drives filament extrusion. Commercial Standard Filament Extruder (17): Classic filament extruder, compatible with the majority of 3D printers available on the market. Filament Feed Inlet (18): Area where the filament to be printed is introduced.

[0021] [Fig. 2]: Overview, bottom perspective view of the 3D printing head rotary with liquid cooling. Main Heating Body (1): Central part of the head which heats the material for extrusion. Rotary Nozzle Sub-Assembly (6): Rotary nozzle that can take different shapes (rectangular, oblong, etc.) and is interchangeable. Heating Cartridge (7): Cartridge heating the Main Heating Body Coolant Inlet / Outlet (9): Coolant inlets and outlets allowing cooling of the cold zone of the head. Support Body (10): Body supporting the various components. Cold Zone of the Head (13): Upper part of the head, thermally insulated from the Main Heating Body. Rotary Nozzle Drive Gear (14): Gear that drives the nozzle in rotation. Nozzle Rotation Drive Motor (15): Motor that drives the rotating nozzle, located in a cold area to avoid the effects of heat. Extrusion drive motor (16): Motor that drives filament extrusion. Commercial Standard Filament Extruder (17): Classic filament extruder, compatible with the majority of 3D printers available on the market. Filament Feed Inlet (18): Area where the filament to be printed is introduced.

[0022] [Fig. 3]: Cross-sectional view along the XY plane of the rotating 3D printing head Main Heating Body (1): Central part of the head which heats the material for extrusion. Rotating Body (2): A rotating metal body with good thermal conductivity, such as copper, is internally threaded to accommodate the rotary nozzle sub-assembly (6), (6a), (6b). This body is also designed to receive the rotating drive pinion (14), thus enabling the transmission of rotational motion to the nozzle. Rotary Nozzle Subassembly: Similar to a standard commercial subassembly, it consists of three parts (6), (6a), and (6b), assembled by press fitting or any other suitable assembly method. This subassembly is designed to screw into the rotating body (2). Parts (6) and (6b) may be made of metal with good thermal conductivity, while part (6a) may be made of metal with low thermal conductivity, in order to ensure optimal control of heat dissipation and limit heat transfer between the critical hot and cold areas of the nozzle. The element (6) having minimal clearance with the bore of the main heating body (1) is heated by convection by this main heating body. The element (6b) being screwed into the rotating body (2) is cooled by this rotating body which itself is cooled by the cooling block (13) by convection, the clearance between the rotating body and the cooling block being small. Upper Rotating Body Guide Bearing (4): Bearing ensuring upper rotational guidance of the rotating nozzle. Lower Rotating Body Guide Bearing (3): Bearing ensuring lower rotational guidance of the rotating nozzle. Pinion Locking Nut on Rotating Body (5): This nut secures the nozzle's swivel drive gear (14) to the rotating body (2). It ensures a secure assembly, firmly holding the pinion in position to efficiently transmit rotational movement to the nozzle, while still allowing for disassembly for printhead maintenance. Drive pinion (15a): Pinion which transmits the movement of the motor to the rotation gear of the nozzle (14). Filament Guide Tube (8): An intermediate tube positioned between the extruder and the rotating print head, designed to guide the filament to the rotating print head. This tube ensures continuous filament feeding. Cold Zone of the Head (13): Upper part of the head, thermally insulated and cooled. This cold zone houses the bearings that guide the rotating body. Nozzle Swivel Drive Gear (14): Gear driven by the rotation motor (15) via the drive pinion (15a). This gear is integral with the rotating body (2) and enables the rotation of the nozzle. Commercial Standard Filament Extruder (17): Example of a classic filament extruder, compatible with most 3D printers available on the market. Filament Feed Inlet (18): Area where the filament is introduced to be melted and extruded. Zone in which the filament is in a solid state (21): This zone corresponds to the part of the device where the filament of material remains in a solid state before entering the heated areas of the print head. Zone in which the filament is in a molten or liquid state (22): In this zone, the filament reaches a molten or liquid state, which allows its continuous extrusion through the printing nozzle to form the layers of material. Transition zone in which the filament is in an indeterminate state (23): This zone represents the temperature range between the solid and molten states of the filament, where the material is partially molten but not yet completely liquid. This transition zone ensures a gradual temperature increase, preparing the filament to reach its fully molten state.

[0023] [Fig.4]: Exploded view of a Rotary Nozzle Sub-Assembly with the Rotary Body The nozzle subassembly, consisting of parts (6), (6a), and (6b), is designed to be screwed into the rotating body (2), thus allowing easy replacement of the nozzle by simply unscrewing it when cold. The rotating nozzle subassembly (6b) is screwed into the rotating body (2), which is itself secured to the rotating pinion (14) by a nut or other suitable mechanical fastener. The rotating body (2) may have flats (2a) or specific indexing at the point where the rotating pinion (14) is attached. These features prevent the pinion from slipping on the rotating body, ensuring reliable and precise transmission of the rotational motion. The rotating body (2) is mounted on bearings (3) and (4), ensuring precise rotational movement in the cold zone of the head. The nozzle tip (20) can have various shapes, such as oblong, oval, or any other suitable configuration. This nozzle tip can also be an added part (6c), fixed by screwing, crimping, or other fastening method. To ensure precise positioning during reassembly after maintenance, the print nozzle can be indexed using two flat areas (21).

[0024] [Fig.5]: Operating principles of the post-processing software Left side of the figure - original path: Large Diameter Nozzle Used to Calculate Origin Path (30): Large diameter nozzle used by the standard software to generate the initial path. Origin Path in Dotted Line (31): Origin trajectory generated by the standard software, represented in dotted line. Direction of Movement of the Origin Path (32): Direction of movement of the path generated by the standard software. Minimum Possible Radius with the Original Path (33): Minimum radius achievable with the large diameter nozzle during the initial path. Right side of the figure - Modifications made by the post-processing software: Shape of the Rotary Nozzle (34): Shape of the rotary nozzle used by the post-processing to optimize the path. Direction of Movement of the Path (35): Direction of movement after processing by the post-processing software. Paths Added by Post-processing Software (36): Additional paths added by the software to optimize the corners and angles of the original path. Minimum Possible Radius with Rotary Nozzle (37): New minimum radius achievable thanks to the shape of the rotary nozzle. At the Ends of the Added Paths, Nozzle Positioned According to the Median (38): The nozzle is oriented according to the median of the trajectories at the ends of the additional movements. Nozzle Positioned Perpendicular to the Direction of Travel (39): The nozzle is oriented perpendicular to the direction of travel to improve material flow.

[0025] [Fig.6]: Operating principles of the post-processing software during print width variations Figure 6 illustrates how the post-processing software manages print width variations based on the geometry of the slicing points. In the upper part of the figure, points (61) to (66) represent an example of original slicing points generated by the standard slicing software according to the print direction (67). Contours (70) to (74) show the molten material deposits produced by a round print nozzle, precisely following the original slicing points and taking into account the print width defined by the slicing software. In the lower part of the figure, points (61') to (66') also represent the same original pass-through points along the printing direction (67'), but the material deposition is modified to be carried out by a rotating printing nozzle with a rounded rectangular cross-section. The fused material deposition contours (70') to (74') follow these pass-through points while incorporating nozzle rotations, calculated and adjusted for each pass-through point, allowing the printing width to be precisely adapted to the desired contours. This process optimizes the adjustment of the printing geometry without degrading contour accuracy in areas requiring width variations.

Claims

Demands

1. A 3D printer print head comprising a rotating body (2) driven by a motor (15), a rotating nozzle (6) fed by filament (19) and passing successively through a cold zone (21), where the filament is kept in a solid state, and a heated zone (22), where the filament becomes liquid or pasty, characterized in that the rotating nozzle allows for infinite rotation. The nozzle rotation control system is compatible with standard 3D printer controllers.

2. Print head according to claim 1, characterized in that the rotation of the nozzle (6) is ensured by a drive system comprising the stepper motor (15) coupled to a gear train (14), said system allowing infinite and controlled rotation of the nozzle, with indexed positioning allowing the orientation of the nozzle to be adapted according to the printing path.

3. A print head according to any one of the preceding claims, characterized in that the seal between the rotating nozzle (6) and the rotating body (2) is ensured by the specific design of the rotary nozzle subassembly, which connects the hot zone (22) and the cold zone (21) by means of a low thermal conductivity metal section (23), ensuring effective thermal insulation and preventing material leakage; the cooling of the upper part of the rotary nozzle subassembly is achieved by thermal conduction with the cold zone of the print head; the lower part of the subassembly is heated by conduction via its contact with the main heating body (1), enabling the filament to melt in the heating zone.

4. Print head according to any one of the preceding claims, characterized in that the rotating nozzle (6) is driven by a drive mechanism comprising a stepper motor (15) and a gear (14) allowing precise control of its rotation, and in that the rotation of the nozzle is dynamically adjusted according to variations in the trajectory of the printing path, in order to improve the accuracy of the prints in the angles and changes of direction of the printed model.

5. Print head according to any one of the preceding claims, characterized in that the rotation control the nozzle (6) is managed by a control device integrating a post-processing module applied to a standard GCode file, said module automatically adapting the movements of the nozzle (36) according to the printing trajectory, optimizing the movements in the corners and angles of the model in order to reduce printing irregularities and improve the geometric accuracy of the printed parts.

6. A print head according to claim 5, characterized in that the control device generating the print path is capable of producing paths of variable width, with post-processing of the G-code file enabling automatic optimization of print widths in areas requiring reduction. This post-processing adjusts the nozzle rotation instructions (6) to ensure adaptation of the print width, particularly in areas with complex geometries or small dimensions, thus improving the accuracy and quality of the final print.

7. Print head according to any one of the preceding claims, characterized in that the rotating nozzle (6) has a shape selected from a set of configurations including a rectangular shape, a rounded rectangular shape, an oblong shape and an oval shape.

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