Extruder device for 3D printing

Abstract

An extruder device for 3D printing, configured to be fed with extrusion material granules, comprises an extrusion cylinder (4), one or more heating members (6) associated with the extrusion cylinder (4), an extrusion screw (8) rotatably mounted in the extrusion cylinder (4), and an electric motor-gearbox assembly (3) that drives the rotation of the extrusion screw (8). The body of the extruder device includes a hollow main core (2) having a through cavity (200) within which is disposed a drive shaft (9) connecting the electric motor-gearbox assembly (3) to the extrusion screw (8). A hopper for feeding extrusion material granules to the extrusion cylinder (4) is defined by a lower portion (201) of the internal cavity (200) of the main core (2), having a substantially tapered conical configuration, whose axis substantially coincides with the main axis (2A) of the extruder device. The main core (2) has a granule inlet (22), through which the granules enter the main core (2) pushed by a pressurized air flow. Said inlet (22) is configured and arranged to feed the granules in a substantially tangential direction into an upper portion (203) of the internal cavity (200) of the main core (2) which is configured as a circumferential channel. The drive shaft (9) carries an auger (10) to push the extrusion material granules into said internal coaxial hopper (201) defined by the lower portion of the internal cavity (200) of the main core (2).

Description

[0001] "Extruder device for 3D printing"

[0002] ****

[0003] Field of the invention

[0004] The present invention relates to an extruder device for 3D printing, of the type configured to be fed with extrusion material granules. In particular, the invention relates to an extruder device for 3D printing of the type comprising:

[0005] - an extruder body, including an extrusion cylinder defining a main axis of the extruder device, and having an inlet end and an outlet end provided with an extrusion nozzle,

[0006] - one or more heating members associated with the extrusion cylinder, to heat the extrusion material progressing within the extrusion cylinder toward the extrusion nozzle,

[0007] - an extrusion screw rotatably mounted within the extrusion cylinder, to advance the extrusion material within the extrusion cylinder,

[0008] - an electric motor-gearbox assembly carried by the extruder body, to drive the rotation of the extrusion screw, and

[0009] - a hopper for feeding extrusion material granules to said extrusion cylinder.

[0010] Prior art

[0011] Extruder devices for 3D printing having the above-mentioned characteristics are known and have been used for some time. In conventional solutions, said hopper for feeding extrusion material granules is arranged outside the extruder body, which limits the maneuverability of the extruder device, as it is necessary to keep the hopper in a substantially vertical position to ensure proper feeding of the extrusion material granules into the extruder body.

[0012] The present invention stems from the need to overcome the aforementioned drawback, by providing an extruder device that can be moved into any position and orientation.

[0013] An extruder device having the characteristics indicated in the preamble of claim 1 is known from document US 11 ,597,118 B2. A further solution is known from document CN 205,386,932 U. Object of the invention

[0014] It is therefore an object of the present invention to provide an extruder device for 3D printing that can operate correctly and efficiently in any position and orientation.

[0015] A further object of the invention is to achieve said goal with an extruder device having a relatively simple and low-cost structure.

[0016] A further object of the invention is to provide an extruder device of the aforementioned type that exhibits high operational efficiency, thanks to improved flow of extrusion material granules within the extruder device, with reduced granule feeding time and a consequent increase in device productivity.

[0017] A further object of the invention is to provide an extruder device of the aforementioned type in which the feeding of extrusion material granules into the extrusion cylinder is ensured efficiently, continuously, and stably, even when the extruder device is in a position where granule feeding is not assisted by gravity.

[0018] Yet another object of the invention is to provide an extruder device of the aforementioned type in which the quality of the 3D printing process is improved, thanks to more uniform feeding of extrusion material granules within the extruder device.

[0019] Yet another object of the invention is to provide an extruder device of the aforementioned type equipped with a highly efficient temperature control system.

[0020] Summary of the invention

[0021] To achieve one or more of the aforementioned objects, the invention relates to an extruder device for 3D printing having the characteristics indicated in the appended claim 1 .

[0022] Thanks to said characteristics, the extruder device according to the invention can operate correctly and reliably even when it has an orientation where gravity does not assist the movement of granules toward the extrusion cylinder.

[0023] Some known devices can operate correctly even in an inclined position, but not in directions that do not favor granule material flow.

[0024] In the extruder device according to the invention, the extrusion material granules are fed directly into the cavity of the hollow main core of the device through a tube where the granules are forced by a pressurized air flow. The granules enter tangentially into said upper portion of the internal cavity of the main core, which is configured as a circumferential channel, after which they are fed to the extrusion cylinder by the central coaxial hopper defined by the lower portion of the internal cavity of the main core.

[0025] In a preferred embodiment, said drive shaft carries an auger member disposed within the internal cavity of the main core, to promote the advancement of granules toward said internal coaxial hopper defined by the lower portion of the internal cavity of the main core.

[0026] The device according to the invention, unlike known devices, does not include any mechanical device (such as a vibrator or paddle) to facilitate material flow.

[0027] Generally, other extruders can tilt but not in directions that do not favor granule material flow.

[0028] In our case, thanks to the integrated conveying / hopper system, the material always reaches the inlet and can be "forced" toward the inlet by a helix integral with the screw.

[0029] In the preferred embodiment, an auxiliary body is associated with the main body, carrying an outlet for the granule feeding air flow and an inlet for a cooling air flow around the external surface of the main core. A filter is associated with said outlet of the auxiliary body, and a filter and a fan for activating a cooling airflow around the external surface of the main core are associated with said inlet of the auxiliary body, said external surface preferably being provided with fins to promote heat exchange with the cooling air flow.

[0030] Still referring to the preferred embodiment, an emission device for a temperature-controlled air flow is associated with the extrusion nozzle, configured as a toroidal volume surrounding the extrusion nozzle and having one or more circumferentially arranged openings to emit an annular air flow for controlling the temperature of the printing area. Said toroidal volume is provided with a cold air supply conduit, in which a cooling device is interposed, and a hot air supply conduit, in which a heating device is interposed. The heating members associated with the extrusion tube are, for example, in the form of heating bands surrounding the extrusion tube and in turn protected by a protective casing.

[0031] Thanks to all the aforementioned characteristics, the invention is able to meet all the objectives specified above.

[0032] Brief description of the drawings

[0033] Further characteristics and advantages of the invention will emerge from the following description with reference to the accompanying drawings, provided purely by way of non-limiting example, wherein:

[0034] - Figure 1 is a perspective view of a preferred example of an embodiment of the extruder device according to the invention,

[0035] - Figure 2 is an exploded perspective view of the device of Figure 1 ,

[0036] - Figures 3, 4 are two elevation views of the device of Figure 1 ,

[0037] - Figures 5-7 are sectional views along lines V-V, VI-VI, and VII-VII of Figures 3, 4,

[0038] - Figure 8 is a perspective view of the main core of the extruder device of Figure 1 ,

[0039] - Figure 9 is a further perspective view of the main core of Figure 8,

[0040] - Figures 10, 11 are sectional views along lines X-X and XI-XI of Figure 9,

[0041] - Figure 12 is a perspective view of a manipulator robot equipped with an extruder device according to the invention.

[0042] Detailed description of the invention

[0043] With reference to the drawings, the number 1 indicates as a whole an extruder device for 3D printing, configured to be fed with extrusion material granules.

[0044] With particular reference to Figure 2, the device 1 comprises a hollow main core 2 having a substantially cylindrical through cavity, whose axis, indicated as 2A, defines the main axis of the extruder device.

[0045] The main core 2 has a first end 20 to which an electric motor-gearbox assembly 3 is rigidly connected, including an electric motor 30 and a gearbox 31 .

[0046] The main core 2 has a second end 21 (see Figures 10, 11 ) to which the inlet end 40 of an extrusion cylinder 4 is rigidly connected. The extrusion cylinder 4 has an outlet end 41 provided with a dispensing nozzle 5.

[0047] Still referring to Figure 2, the extrusion cylinder 4 is surrounded by multiple heating bands of any known type, to cause heating and melting of the extrusion material granules progressing within the extrusion cylinder 4. The heating bands 6, in the illustrated example, are protected by a casing 7 that internally has engagement elements (not visible in the drawings) for coupling with corresponding engagement elements 6A carried by the heating bands 6.

[0048] Inside the extrusion cylinder 4 is arranged an extrusion screw 8 configured to advance the extrusion material through the extrusion cylinder 4. The extrusion screw 8 is made in one piece, in the illustrated example, with a drive shaft 9 rotationally driven by the electric motor-gearbox assembly 3 and disposed through a through cavity of the main core 2.

[0049] In the preferred embodiment illustrated here, the drive shaft 9 carries an auger 10 to promote the advancement of the extrusion material granules toward the extrusion cylinder 4, as will be described in more detail below.

[0050] With particular reference to Figures 10, 11 , the main core 2 has a cylindrical through cavity 200 with a lower portion 201 having a substantially tapered conical configuration, whose axis coincides with the main axis 2A of the extruder device. The conical lower portion 201 of the internal cavity 200 of the main core 2 serves as an internal coaxial hopper to convey the extrusion material granules toward a lower outlet 202 (Figures 10, 11 ) communicating with the inlet end 40 of the extrusion tube 4.

[0051] The upper portion of the internal cavity 200 of the main core 2 defines a circumferential channel 203 that receives the incoming extrusion material granules into the central core 2. For this purpose, the body of the main core 2 has an inlet opening 22 (see Figure 9) through which the extrusion material granules enter tangentially into the circumferential channel 203 defined by the upper portion of the internal cavity 200.

[0052] With reference to Figure 2, the granules are fed to the inlet 22 via a tube 11 traversed by a pressurized air flow. The pressurized air flow produces forced feeding of the granules inside the main core 2, through the inlet 22.

[0053] The extrusion material granules enter tangentially into the circumferential channel 203 and then proceed toward the outlet 202 of the main core 2 communicating with the extrusion cylinder 4.

[0054] As visible in Figures 6, 7, the auger 10 carried by the drive shaft 9 is arranged inside the cavity 200, adjacent to the lower hopper 201 and is thus capable of pushing the granules toward the extrusion cylinder 4 even when the extruder device has an orientation where gravity does not favor the feeding of granules into the extrusion cylinder 4.

[0055] With reference to Figures 1 , 2, the number 12 indicates as a whole an auxiliary body, for example made of plastic material, defining an outlet (not visible in the drawings) for the granule feeding air flow exiting the main core 2 and an inlet (not visible in the drawings) for a cooling air flow intended to flow over the external surface of the main core 2. The auxiliary body 12 includes a fan 13 for activating the cooling air flow of the main core 2. The main core 2 has an external surface preferably provided with cooling fins, to improve heat exchange with the external cooling air flow.

[0056] Still referring particularly to Figure 2, an emission device 14 for a temperature-controlled air flow is associated with the extrusion nozzle 5. The device 14 includes a body 15 in the form of a toroidal volume surrounding the extrusion nozzle 5 and having one or more openings 5A (Figures 6, 7) facing downward (with reference to the drawings) to emit an annular temperature-controlled airflow. For this purpose, the hollow toroidal volume 15 communicates with a first conduit 16 for cooling air and a second conduit 17 for heating air. A cooling device 16A of any known type is interposed in the conduit 16, while a heating device 17A of any known type is interposed in the conduit 17. Referring again to Figure 9, the main core 2 has a further opening 23 for mounting an electrical connector intended to be connected to a cable 24 (Figure 2) including a power supply line and one or more data communication lines.

[0057] As visible in Figures 8, 9, and 11 , the body of the main core 2 has walls including inspection windows 25, which allow checking the correct feeding of the extrusion material granules within the extruder device.

[0058] Figure 12 illustrates the extruder device 1 in the operating condition where it is carried by a manipulator robot 300 of any known type. For this purpose, a flange 301 (see Figure 1 ) is also rigidly connected to the main core 2 for connection to a robot wrist. Naturally, while maintaining the principle of the invention, the construction details and embodiments may vary widely with respect to what has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the present invention, as defined in the appended claims.

Claims

CLAIMS1. Extruder device for 3D printing, configured to be fed with extrusion material granules, comprising:- an extruder body, including an extrusion cylinder (4) defining a main axis (2A) of the extruder device, and having an inlet end (40) and an outlet end (41 ) provided with an extrusion nozzle (5),- one or more heating members (6) associated with the extrusion cylinder (4), to heat the extrusion material progressing within the extrusion cylinder (4) toward the extrusion nozzle (5),- an extrusion screw (8) rotatably mounted within the extrusion cylinder (4), to advance the extrusion material within the extrusion cylinder (4),- an electric motor-gearbox assembly (3) carried by the extruder body, to drive the rotation of the extrusion screw (8), and- a hopper for feeding extrusion material granules to said extrusion cylinder (4), wherein:- the extruder body comprises a hollow main core (2), having a first end (20) rigidly connected to said electric motor-gearbox assembly (3) and a second end (21 ) opposite the first end, to which the inlet end (40) of the extrusion cylinder (4) is connected,- the hollow main core (2) has a through cavity (200) within which is disposed a drive shaft (9) connecting the electric motor-gearbox assembly (3) to said extrusion screw (8),- the hopper (201 ) for feeding extrusion material granules to said extrusion cylinder (4) is defined by a lower portion of the internal cavity (200) of the main core (2), having a substantially tapered conical configuration, whose axis substantially coincides with the main axis (2A) of the extruder device,- the main core (2) has a granule inlet (22), said extruder device being characterized in that:- said inlet (22) is configured to be connected to a tube (11 ) for feeding the extrusion material granules by means of a pressurized air flow,- said inlet (22) is disposed in an upper portion (203) of the internalcavity (200) of the main core (2), above the lower portion (201 ) of the internal cavity that defines the hopper (201 ) for feeding the extrusion material granules to said extrusion cylinder (4),- said inlet (22) is configured and arranged to feed the granules in a substantially tangential direction into said upper portion (203) of the internal cavity (200) of the main core (2), and- said upper portion (203) of the internal cavity (200) is configured as a circumferential channel.

2. Extruder device according to claim 1 , characterized in that said drive shaft (9) carries an auger member (10) disposed within the internal cavity (200) of said main core (2), to push the granules toward said internal coaxial hopper (201 ) defined by the lower portion of the internal cavity (200) of the main core (2).

3. Extruder device according to claim 1 , characterized in that an auxiliary body (12) is associated with said main core (2), carrying an outlet for the granule feeding air flow and an inlet for a cooling air flow, to cool the external surface of the main core (2).

4. Extruder device according to claim 3, characterized in that a filter is associated with said outlet of the auxiliary body (12), and that a filter and a fan (13) are associated with said inlet of the auxiliary body (12) to activate a cooling air flow around the external surface of the main core (2).

5. Extruder device according to claim 1 , characterized in that a device (14) for emitting a temperature-controlled air flow is associated with said nozzle (5), configured as a hollow toroidal body (15) surrounding the extrusion nozzle (5) and having one or more openings (15A) arranged circumferentially to emit an annular air flow.

6. Extruder device according to claim 5, characterized in that said hollow toroidal body (15) is provided with a cold air supply conduit (16) in which a cooling device (16A) is interposed and a hot air supply conduit (17) in which a heating device (17A) is interposed.

Images