DESC:FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
The Patents Rules, 2003

COMPLETE SPECIFICATION
[See section 10 and rule 13]

TITLE: “A MIXING ASSEMBLY FOR A THREE-DIMENSIONAL PRINTER”

Name and address of the Applicant:
TVASTA MANUFACTURING SOLUTIONS PRIVATE LIMITED, an Indian company having its registered office at 5/1, 2nd Main, National HBCS, Plan-2, Prashanth Nagar, Bengaluru - 560079, Karnataka, India

Nationality: INDIAN

The following specification particularly describes the invention and the manner in which it is to be performed.
TECHNICAL FIELD

Present disclosure relates in general to a field of additive manufacturing. Particularly, but not exclusively, the present disclosure relates to three-dimensional printing. Further, embodiments of the present disclosure disclose a mixing assembly for mixing and injecting admixtures with print material in a three-dimensional printing system.

BACKGROUND OF THE INVENTION

Civil construction has evolved over time. Conventionally, constructing a simple design, such as a two or three storied building, would take considerable amount of time and labor. Such long construction periods had several reasons. Some of the reasons may be lack of skilled labor, long set-in period of the concrete material used at the time and most importantly, weather-related delays and raw material availability. With the advent of modern manufacturing, methods of constructing structures have been enhanced or improved predominantly by considering the following factors including, but not limited to, rate of construction, quality of constructions, resource management, and the like. In the recent past, there has been a rise in the demand for constructing structures having various dimensions and complex designs. Such complex constructional requirements are met by employing three-dimensional printers. The three-dimensional printers have introduced modern methodology of constructing various complicated and unique structures.

Three dimensional printers, in general, are employed in manufacturing structures having myriad of complex shapes and/or patterns without requirement of a prefabricated die or mold. The three dimensional [3D] printers generally include a three-dimensional coordinate printing assembly and platform to hold such printable material [or also referred to printing media] for constructing the structures. With advent of technology, the 3D printers are also configured to dispense fluid media including, but not limited to, concrete, from a nozzle to stratify such concrete media over each other until required dimensions and/or profile of the structure is achieved. One of the many challenges in conventional concrete 3D Printers may be stability/buildability of such concrete media for establishing stratification for building the structures. Characteristics including, but not limited to, humidity and fresh-state and/or soft consistency of the concrete media, may be some of the parameters that may limit dimension of the structures to be printed in a single action and result in questionable stability of the printed layer/structure which forms misaligned vertical elements.
Further, when slight overhangs have to be constructed and if the concrete does not harden quickly, the concrete will drop off from the structure due to insufficient hardening. Therefore, printing of components with a number of layers and/or overhangs is limited without the material setting quickly in the previous layers.

To address such problems associated with stability and buildability using concrete materials, conventionally, accelerators are added to the concrete media during preparation prior to introduction into the 3D printer. The accelerators may be chemical admixtures that may reduce
setting time for hardening of the concrete media, thereby shortening cure time of the concrete
media and improving stability and buildability of structures therefrom. Conventionally, the accelerators may be added to the concrete mixer when preparing (stirring/mixing) the concrete
media that may be readily introduced for dispensing/printing via the 3D printer. However, when the accelerators are added to the concrete mixer, there is a possibility that, in some instances the concrete may harden within the pipes that are being used to pump the concrete into the 3D Printer. Since the concrete is to remain in the fluid state as much as possible during the pumping process and hardening being necessary only after the concrete is extruded out of the 3D Printer, it is vital to add the accelerators once the concrete mixture is at the nozzle or once it is out of the 3D Printer. Thus, early addition of an accelerators at the mixer (as done conventionally) poses a risk of concrete getting hard in the pipes prior to or during printing, which would result in the components of the 3D printer getting damaged and leading to financial losses.

Therefore, the conventional systems and methods of 3D printing concrete lack(s) the ability to
harden the concrete without posing the risk of damaging the 3D printer. The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional arts.

The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional configuration of starter motor cranking systems of the engine.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the conventional system or method are overcome, and additional advantages are provided through the provision of the method as claimed in the present disclosure.

Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the disclosure, a mixing assembly for a three-dimensional printer is disclosed. The assembly includes a hopper configured to receive and accumulate a base print material and a first auger is defined within the hopper. The first auger extends along a first longitudinal axis of the hopper, where the first auger mixes the base print material. The mixing assembly also includes a confluence chamber configured to receive the base print material from the hopper. A second auger is defined within the confluence chamber and extends along a second longitudinal axis of the confluence chamber. An injector is fluidly connected to the confluence chamber for injecting an accelerator into the confluence chamber during operation of the second auger. Further, an extrusion head is configured to the confluence chamber for printing a mixture of the base print material and the accelerator.

In an embodiment of the disclosure, a first motor is coupled to the first auger for rotating the first auger and directing the base print material from the hopper to the mixing assembly.

In an embodiment of the disclosure, at least one scrapper blade is fixedly connected to the first auger and is accommodated within the hopper where, the scrapper blade rotates with the first auger for agitating and scraping the base print material from inner surfaces of the hopper.

In an embodiment of the disclosure, a second motor is coupled to the second auger for rotating the second auger and for mixing the base print material with the accelerator.

In an embodiment of the disclosure, the mixing assembly is rotatably connected to the hopper and, the mixing assembly rotates along the first longitudinal axis of the hopper.

In an embodiment of the disclosure, a third motor is connected to the mixing assembly for facilitating the rotation of the mixing assembly along the first longitudinal axis.

In an embodiment of the disclosure, the extrusion head is rotatably connected to the confluence chamber and, the extrusion head rotates along the second longitudinal axis of the mixing assembly.

In an embodiment of the disclosure, a fourth motor is connected to the extrusion head for facilitating the rotation of the extrusion head along the second longitudinal axis.

In an embodiment of the disclosure, the injector is positioned at a predetermined angle with respect to a central axis of the confluence chamber.

In an embodiment of the disclosure, a solenoid valve positioned proximal to a region where the hopper is fluidly connected to the mixing assembly where, the solenoid valve closes when the printing is terminated and cuts off the flow of base printing material into the confluence chamber.

In an embodiment of the disclosure, the solenoid valve terminates the operation of the injector when the printing is terminated.

In an embodiment of the disclosure, the injector is positioned proximal to the extrusion head and the base print material is mixed with the accelerators near the extrusion head.

In one non-limiting embodiment of the disclosure, a three-dimensional printer is disclosed. A hopper is configured to receive and accumulate a base print material and a first auger is defined within the hopper. The first auger extends along a first longitudinal axis of the hopper, where the first auger mixes the base print material. The mixing assembly is fluidly connected to the hopper, where the mixing assembly includes a confluence chamber configured to receive a base print material from a hopper. A second auger is defined within the confluence chamber and extends along a second longitudinal axis of the confluence chamber. An injector is fluidly connected to the confluence chamber for injecting an accelerator into the confluence chamber during operation of the second auger. Further, an extrusion head is configured to the confluence chamber for printing a mixture of the base print material and the accelerator.

In one non-limiting embodiment of the disclosure, a method of printing material from a three-dimensional printer with a mixing assembly is disclosed. The method includes aspects of loading and accumulating a base print material in a hopper. The base print material is directed through the hopper by operating a first auger accommodated within the hopper where, the first auger extends along a first longitudinal axis of the hopper. The base print material from the hopper is then received by a confluence chamber. The next step involves the aspect of injecting an accelerator into the confluence chamber by an injector where, the injector is positioned proximal to an extrusion head. Further, the base print material is mixed with the accelerator by operating a second auger accommodated within the confluence chamber where, the second auger extends along a second longitudinal axis of the confluence chamber. Lastly, the mixture of the base print material and the accelerator is printed by an extrusion head where, the injector is positioned proximal to the extrusion head and the base print material is mixed with the accelerators near the extrusion head.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

Fig. 1 illustrates a schematic side view of a three-dimensional printer, in accordance with an embodiment of the present disclosure.

Fig. 2 illustrates a schematic side view of a mixing assembly and confluence chamber in the three-dimensional printer of Fig. 1, in accordance with an embodiment of the present disclosure.

Fig. 3 illustrates a perspective view of a second auger in the mixing assembly of the three-dimensional printer, in accordance with an embodiment of the present disclosure.

Fig. 4 illustrates a side view of an embodiment of the mixing assembly from the Fig. 2 with an injector, in accordance with an embodiment of the present disclosure.

Figure 5 illustrates schematic block diagram of a system for controlling operating the three-dimensional printer, in accordance with an embodiment of the present disclosure.

Figure 6 is a flow chart of a method of printing material from a three-dimensional printer, in accordance with an embodiment of the present disclosure.

The figure depicts embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the three-dimensional printer without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other system for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure. The novel features which are believed to be characteristic of the disclosure, as to its organization, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a system that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such mechanism. In other words, one or more elements in the device or mechanism proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the mechanism.

As used in the description below the term “control unit” refers to a hardware component such as at least one processor, volatile memory or nonvolatile memory, software comprising instructions executable by a processor, or a combination of software and hardware. The control unit may be adaptive to the vehicle audible device control unit or may be a centralized control unit of the vehicle or may be a dedicated control unit to the system associated with the centralized control unit of the vehicle. Further, the memory unit may be integral part of the control unit or may be communicatively coupled to control unit. The control unit may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processing unit may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM’s application, embedded or secure processors, other line of processors, and the like.

The word “base print material” used in the description below, may be one of concrete, cement, and any other material suitable for constructing structures.

The word “accelerator” used in the description below, may be an admixture that may be added to the base print material to modify properties of the base print material including but not limited to hardening rate.

Fig. 1 illustrates a schematic side view of a three-dimensional printer (200) [hereinafter referred to as “the printer”]. The printer (200) may include a hopper (17) for receiving a base print material. The hopper (17) may be designed in an inverted conical shaped end with a cylindrical shaped hollow body. The shape and configuration of the hopper (17) must not be considered as a limitation since, the hopper (17) may be defined by any shape and configuration suitable for receiving and storing the base print material. The hopper (17) may also include a first conduit (21) that is connected to one end of the conical shaped end of the hopper (17). The hopper (17) may be defined by an inlet (18) along a top region of the hopper (17). The inlet (18) may be used to load or feed the hopper (17) with the base printing material. The inlet (18) may also be configured such that the base printing material inside the hopper (17) may be partially exposed to the atmosphere. The hopper (17) may be defined by a first longitudinal axis (A-A). The hopper (17) may include a first auger (15) that extends along the first longitudinal axis (A-A). The first auger (15) may be accommodated within the hopper (17) and the first auger (15) may be rotatably connected with the hopper (17). The top end of the hopper (17) may also accommodate a first motor (10) that is connected to the first auger (15). A drive shaft of the first motor (10) may be connected to the first auger (15) and the first auger (15) may rotate within the hopper (17). The coupling arrangement between the first auger (15) and the drive shaft of the motor (10) may enable the rotational motion of the drive shaft in the first motor (10) to be imparted to the first auger (15). The hopper (17) may herein act as a reservoir that receives and stores the base print material and the first auger (15) may force the base print material through the first conduit (21) of the hopper (17). The rotational motion of the first auger (15) may extrude the base print material out of the hopper (17). Further, the rotation of the first auger (15) may also enable the removal of trapped air molecules inside the base print material. Since, the base print material inside the hopper (17) is exposed to the atmosphere through the inlet (18) of the hopper (17), the trapped air molecules may escape out to the atmosphere as the base print material is agitated by the rotation of the first auger (15). Further, the first motor (10) may be connected to a control unit (19) [seen from Fig. 5]. The control unit (19) may vary the rotational speed of the first motor (10) and thereby also vary the rotational speed of the first auger (15). Increasing the rotational speed of the first auger (15) may increase the rate of extrusion of the base print material and vice versa. Thus, the rate of extrusion of the base print material from the hopper (17) is controlled by controlling the rotational speed of the first auger (15).

The auger (17) may be an elongated shaft with spiral extensions on the surface of the shaft. One end of the shaft may be connected to the drive shaft of the first motor (10) and may rotate along with the drive shaft of the first motor (10). The other end of the shaft may be freely suspended within the hopper (17) and may extend into the first conduit (21) of the hopper (17). The spiral extensional may be configured along a region of the shaft that lies in the vicinity of the conical shaped body of the hopper (17). The spiral extensions on the shaft may extend from the conical shaped body of the hopper (17) to the tip of the shaft. The diameter of the spiral extensions may gradually reduce through the length of the conical shaped body of the hopper (17). In an embodiment, the reduction in diameter of the spiral extensions on the shaft of the first auger (15) may be proportional to the reduction of the diameter of the conical shaped body. The diameter of the spiral extensions may remain the same along the region where the shaft is accommodated in the first conduit (21) of the hopper (17). The spiral extensions on the shaft enables the base print material to be extruded out of the hopper (17). As the first auger (15) rotates, the base print material is pushed downwards by the spiral extensions and the base print material exits the hopper (17) through the first conduit (21) of the hopper (17). The first auger (15) may be configured to handle the base print material with aggregates in the size ranging from 8 mm to 15 mm.

The shaft of the first auger (15) may also be configured with at least one scrapper blade (16) [hereinafter referred to as “the scrapper blade”]. The scrapper blade (16) may be fixedly connected to the shaft and may be configured to rotate along with the shaft of the first auger (15). The dimensions of the scrapper blade (16) may be configured such that the scrapper blade (16) extends substantially along the length of the cylindrical body of the hopper (17). In an embodiment, the scrapper blade (16) may also be configured to extend into the conical shaped body of the hopper (17). The scrapper blade (16) may be configured to agitate the base print material inside the hopper (17). The scrapper blade (16) may also remove the base print material from the inner surfaces of the hopper (17). The base print material may often stick onto the inner surface of the hopper (17) and may not be completely extruded. The scrapper blade (16) may scrape of the base printing material from the inner surfaces of the hopper (17). In an embodiment, the scrapper blade (16) may include a first blade and a second blade. One end of the first blade may be fixedly connected to the shaft whereas, the other end of the first blade may be connected to the second blade. The first blade may be positioned at a pre-determined angle with respect to the shaft whereas, the second blade may be pivotably connected to the first blade. The second blade may extend along the first longitudinal axis (A-A) of the hopper (17) and the second blade may also pivot with respect to the first blade. Subsequently, the second blade may extend outwardly and away from the shaft when the rotation of the shaft is increased. The centrifugal forces acting on the scrapper blade during the rotation of the shaft may cause the second blade to extend outwardly and thereby the agitation of the base print material may also be increased. Consequently, the rate of extrusion may also be increased.

In an embodiment, the diameter of the first conduit (21) may be equivalent to the diameter of the narrowest region of the conical shaped body in the hopper (17).

In an embodiment, the hopper (17) may receive and mix the material including, but not limited to, cement, water, along with any other additive aggregates such as gravel, crushed stone, sand, slag, recycled concrete and geosynthetic aggregates which act as binders and/or complement the binders, based on required consistence or composition for extruding by the printer (200).

In an embodiment, the hopper (17) may be configured to store base print material in the range of 15 kg to 30 kg, The storage capacity of the hopper (17) must not be considered as a limitation since, the hoper (17) of larger dimensions may be constructed for storing a larger quantity of the base print material. The hopper (17) and the first auger (15) may be configured to extrude the base print material at the flow rate ranging from 0.25 kg/min to 12 kg/min.

In an embodiment, the hopper (17) may be configured with a level sensor [not shown] that is connected to the control unit (19). The control unit (19) may further be connected to an indication unit [not shown] where, the quantity or the level of the base print material inside the hopper (17) may be suitably indicated.

The hopper (17) may be connected to a mixing assembly (100) for mixing and extruding the base print material. The mixing assembly (100) may include a second conduit (22) that is fluidly connected to the first conduit (21) of the hopper (17). The second conduit (22) is configured to receive the base print material that is extruded from the hopper (17). The connection between the first conduit (21) of the hopper (17) and the second conduit (22) of the mixing assembly (100) may be facilitated by a bearing assembly (25). The mixing assembly (100) may be rotatably connected to the hopper (17) and, the mixing assembly (100) may be configured to rotate along a first longitudinal axis (A-A) of the hopper (17). The rotation of the mixing assembly (100) along the first longitudinal axis (A-A) may be facilitated by a third motor (13). In an embodiment, the third motor (13) may be connected to the bearing assembly (25) and the second conduit (22) of the mixing assembly (100). The third motor (13) may also be connected to the control unit (19) and the third motor (13) may rotate the mixing assembly (100). This configuration of the mixing assembly (100) rotating about first longitudinal axis (A-A) provides flexibility to the printer (200) for extruding or printing complex shapes.

Fig. 2 illustrates a schematic side view of the mixing assembly (100). The second conduit (22) as seem from Fig. 2 may be configured to extend away from the first longitudinal axis (A-A) of the hopper (17). In an embodiment, the second conduit (22) may be defined arcuately at an angle of 90 degrees and may extend away from the hopper (17). The second conduit (22) may be fluidly connected to a confluence chamber (2). The confluence chamber (2) may also extend at an angle of 90 degrees from the second conduit (22). In an embodiment, the second conduit (22) and the confluence chamber (2) may be an integral component. The confluence chamber (2) may extend along a second longitudinal axis (B-B) that lies parallel to the first longitudinal axis (A-A) of the hopper (17). Further, an injector (6) may be configured to the confluence chamber (2). The injector (6) may be configured to inject the accelerator into the confluence chamber (2). The injector may be positioned at a pre-determined angle with respect to a central axis (C-C) of the mixing assembly (100). In this particular, embodiment, the injector (6) is positioned parallel to the central axis (C-C) of the mixing assembly (100).

The confluence chamber (2) is configured to receive a spray of accelerators sprayed by the injector (6) to mix with the base print material flowing from the first conduit (21). The accelerators may be sprayed in a uniform manner or in a non-uniform manner such that the accelerators impinge and mix with the flowing base print material. In an embodiment, the injector (6) may also atomize the accelerator which is to be sprayed to provide an atomized spray of accelerator to mix with the flowing base print material. Further, the pressure and the rate of spraying the accelerator may be externally controlled to achieve optimal operating conditions.

The confluence chamber (2) also includes a second auger (11). The second auger (11) as seen from Fig. 3, may also include the shaft (23a) with the spiral extensions (23b). The spiral extensions (23b) may be of equal diameter throughout the length of the shaft (23a). One end of the shaft (23a) of the second auger (11) may be connected to a second motor (9). The second motor (9) may impart a rotational motion to the second auger (11) and the second auger (11) may rotate within the confluence chamber (2) of the mixing assembly (100). The second motor (9) may also be connected to the control unit (19) and the rotational speed of the second motor (9) may be controlled by the control unit (19). Rotation of the second auger (11) mixes the accelerators that are sprayed from the injector (6) with the base print material that is extruded from the hopper (17). The confluence chamber (2) and the second auger (11) provide a complete and effective mixing between the base print material and the accelerator which is required for effective hardening of the base print material. The mixture of the base print material and the accelerators may then be extruded through an extrusion head (4). The extrusion head (4) may be connected to a bottom end of the confluence chamber (2). The extrusion head (4) may be a nozzle which guides the mixture of the accelerator and the base print material. The extrusion head (4) may be fluidly connected to the confluence chamber (2) through the bearing assembly (25). The extrusion head (4) may be rotatably connected to the confluence chamber (2) and is configured to rotate along the second longitudinal axis (B-B) of the mixing assembly (100). Further, a fourth motor (12) may be connected to the extrusion head (4) for facilitating the rotation of the extrusion head (4) along the second longitudinal axis (B-B). The second motor (9) may also be connected to the control unit (19) and the control unit (19) may also control the rotation of the extrusion head (4). The rotation of the extrusion head (4) may be used to control the shape of material extrusion. For instance, if a curved edge is to be printed/extruded, the rotation of the extrusion head (4) may be initiated such that a curved edge is extruded, and sharp edges or corners are avoided.

In an embodiment, the extrusion head (4) may be defined with a predetermined profile to extrude the mixture of the base print material and the accelerators based on the structural pattern required to be printed. The profile of the extrusion head (4) may also assist in further mixing the base print material and the accelerator for uniform consistency in composition during extrusion.

In an embodiment, the positioning of the injector (6) may be configured to lie opposite to a region where the base print material exits the second conduit (22) and enters the confluence chamber (2). The dimensions of the confluence chamber (2) may also be configured such that the injector (6) may lie proximal to the extrusion head (4). The mixing of the base print material and the accelerators in the confluence chamber (2) takes place proximal to the extrusion head (4). The mixture is subsequently extruded almost immediately with minimal travelling through the extrusion head (4).

In an embodiment, multiple inlet ports may be configured into the confluence chamber (2). The inlet ports may be used to directly inject the base print material along with binders and additives into the confluence chamber (2).

In an embodiment, the mixing assembly (100) may be configured with at least one solenoid valve (20) for controlling the flow of the base print material into the confluence chamber (2) operated via the control unit (19). The at least one solenoid valve (20) [herein referred to as solenoid valve] may be positioned in the first conduit (21) before the confluence chamber (2). The solenoid valve (20) may also be positioned at a region where the first conduit (21) is fluidly connected with the second conduit (22). Subsequent to the extruding of the material is terminated, the control unit (19) may simultaneously operate the solenoid valve (20) and prevent the flow of the base print material into the confluence chamber (2). Thus, the solenoid valve (20) prevents an excess flow of the base print material into the confluence chamber (2). The solenoid valve (20) also prevents the hardening and clogging of the base print material inside the confluence chamber (2) after the extruding of the mixture is terminated.

In an embodiment, a vibration motor may be mounted on the hopper (17). The vibration motor may cause controlled constant vibrations in the hopper (17) for preventing the sedimentation, accumulation, and stagnation of the base print material in the hopper. Consequently, the wastage involved in the process is reduced and the first auger (15) may work at higher efficiencies.

Fig. 4 illustrates a side view of an embodiment of the mixing assembly (100) for the printer (200). The mixing assembly (100) includes a hollow tube (24) defining a first inlet (7) fluidly connected to a first hose (1) which is adapted to carry the base print material therethrough. The first hose (1) fluidly connects to the hopper (17) with the mixing assembly (100) for injecting the base print material. The mixing assembly (100) also includes a second hose (5) with a second inlet (8). The second inlet (8) and the second hose (5) are configured to receive and supply the accelerator. Further, the mixing assembly (100) includes the confluence chamber (2) defined in the upstream portion of the hollow tube (24) and connected to another end of the first hose (1). The confluence chamber (2) may be defined with a provision to receive the injector (6) which injects the accelerator that is to be mixed with the base print material.

The confluence chamber (2) is configured to receive the spray of accelerator sprayed by the injector (6) to mix with the base print material flowing from the first hose (1). The accelerator may be sprayed in a uniform manner or in a non-uniform manner such that the accelerators impinge and mix with the flowing base print material. In an embodiment, the injector (6) may also atomize the accelerator which is to be sprayed to provide an atomized spray of accelerator to mix with the flowing base print material. Further, the pressure and the rate of spraying the accelerator may be externally controlled to achieve optimal operating conditions. Furthermore, the confluence chamber (2) is connected to a mixing portion (3) which is located further upstream in the hollow tube (24). The mixing portion (3) may consist of plurality of blades which deflect the base print material and accelerator mixture for further mixing. In an embodiment, the mixing portion (3) may be configured with static blades which are positioned at an optimal angle or obliquely positioned so that complete homogenous mixing takes place between the base print material and the accelerator. Additionally, an extrusion head (4) is positioned below the mixing portion (3) at the tip of the hollow tube (24) and is in fluid communication with the mixing portion (3) to receive the base print material and accelerator mixture and extrude the mixture to the desired location.

In an embodiment, the mixing assembly (100) consists of a dosing pump (not shown) connected to an accelerator holding tank (not shown). In an embodiment, the accelerator may be a fluid having various composition as per the requirement to harden the base print material. The dosing pump is configured to pump the accelerator from the accelerator holding tank to the second hose (5) which is adapted to carry the accelerator at high pressure. The second hose (5) is connected to the injector (6) and the injector (6) is adapted to spray the accelerator supplied from the dosing pump into the confluence chamber (2) to mix with the flowing base print material. In an embodiment, the injector (6) may have a circular face or any other geometrical shape having different dimensions. Further, the injector (6) may consist of one or more holes/nozzles which may have uniform or varying dimensions depending on the application. The dimension of the injector (6) and the number of holes/nozzles in the injector (6) may vary with respect to the amount or the force in which the accelerator is to be sprayed into the confluence chamber (2). Furthermore, the holes/nozzles in the injector (6) may be oriented in the same or different directions to assist in uniform mixing of the sprayed accelerator and the base print material in the confluence chamber (2). Also, the injector (6) may be configured such that the pressure of the accelerator within the injector (6) may be 50-200 bar. The high pressure of the accelerator further aids in automatically removing any hardened base print material which may cause blockage. In another embodiment, multiple injectors (6) may be employed in the mixing assembly (100) in multiple directions for spraying the accelerators onto the base print material in the confluence chamber (2) or at any point in the mixing assembly (100) which leads to homogenous mixing of the base print material and the accelerator. To supply the accelerator to multiple injectors (6), a multiple branched second hose (5) may be employed where the single hose end of the multiple branched second hose (5) is connected to the dosing pump and the end having the multiple branches is connected to different injectors (6). Additionally, in an embodiment, the injector (6) may be provisioned within the confluence chamber (2) such that the longitudinal axis of the injector (6) may make an intruded angle of about 25-65 degrees with the central axis of the confluence chamber (2).

In an embodiment, the positioning of the injector (6) may be varied along the second longitudinal axis (B-B) and along the central axis (C-C) of the mixing assembly (100). The position of the injector (6) may be varied based on the required quantity or consistency of the mixture of base print material and the accelerator. The addition of the accelerator may be controlled by varying the position and the angular orientation of the injector (6). The positioning and the angular orientation of the injector (6) may be varied to complement the consistency of the base print material and to match the quantity of the base print material that is being extruded into the confluence chamber (2).

In an embodiment, the second auger (11) may be a mixing blade. The second auger (11) may be any sort of blade which mixes the base print material and the accelerator inside the confluence chamber (2). The shape and configuration of the mixing blade or the second auger (11) must not be considered as a limitation and any configuration which assists or mixes the base print material with the accelerator may be used.

Figure 5 illustrates schematic block diagram of a system (300) for operating the printer (200). The system (300) includes the control unit (19) that is communicatively connected to the first motor (10), the second motor (9), the third motor (13), the fourth motor (12) and the solenoid valve (20). In an embodiment, the control unit (19) may be configured to operate the first motor (10) and the second motor (9) at the same speed. The base print material extruded from the hopper (17) may be configured at the same rate as that of the material extruded from the extrusion head (4). In an embodiment, the operation speed of the second motor (9) may be slightly greater than the operational speed of the first motor (10) which enables the faster mixing of the base print material with the accelerator. The operational speed of the first motor (10) and the second motor (9) may be controlled by the control unit (19) based on the required extruding rate and the required flow rate of the mixture. The third motor (13) and the fourth motor (12) may be used to maneuver the mixing assembly (100) and the extrusion head (4) respectively. An extruding path may already be pre-loaded onto the control unit (19) and the control unit may subsequently control the operation of the third motor (13) for extruding the mixture of the base print material and the accelerator to print a particular/required shape. The control unit (19) may also operate the fourth motor (12) to control the shape of the structural pattern that is extruded.

Figure 6 is a flow chart of a method of printing material from the printer (200). The first step 301 includes the aspect of loading and accumulating the base print material in the hopper (17). The base print material may be loaded to the required levels into the hopper (17). The level sensor in the hopper (17) may detect the quantity of the base print material and the same may be indicated through an indication unit. The first auger (15) may be subsequently operated to agitate the base print material and to remove any air molecules that may be trapped in the base print material. The next step 302 involves extruding the base print material through the hopper (17). The first auger (15) may be operated by the first motor (10) to push the base print material into the first conduit (21) of the hopper (17). The base print material may be extruded by the rotation of the first auger (15) and the flow rate of extruding the base print material may be controlled by regulating the rotational speed first motor (10). The control unit (19) may operate the first motor (10) to required speeds and thereby the flow rate of the base print material may also be controlled based on the requirement. The next step 303 may include the aspect of the base print material being directed into the confluence chamber (2). The confluence chamber (2) may receive the base print material from the hopper (17) through the second conduit (22) of the mixing assembly (100). The next step 304 is with regards to the aspect of operating the injector (6) for injecting the accelerator into the confluence chamber (2). Further, the step 305 involves, mixing the base print material and the accelerator by operating the second auger (11) accommodated within the confluence chamber (2). Once, the base print material being to enter the confluence chamber (2), the accelerator is sprayed or injected into the confluence chamber (2) and the second auger (11) is simultaneously operated. The second auger (11) mixes the base print material with the accelerator. The second auger (11) is connected to the control unit (19) and the rotational speed of the second auger (11) is controlled by regulating the operation speed of the second motor (9). Thereby, the rate of mixing the base print material with the accelerator may also be controlled. Lastly, the step 306 involves the aspect of the mixture of printing/extruding the base print material and the accelerator through the extrusion head (4) of the mixing assembly (100). Since, the injector (6) and the confluence chamber (2) are positioned proximal to the extrusion head (4), the mixing of the base print material and the accelerator takes place proximal to the extrusion head (4) and the mixture is immediately extruded with minimal time for solidifying. Consequently, the mixture is prevented from solidifying inside the mixing assembly (100) and clogging of the printer (200) is also avoided.

In an embodiment, the mixing assembly (100) reduces the risk of pipes getting blocked due to material hardening (since the accelerator is added at the extrusion-head rather than at the hopper). Further, the positioning of the injector (6) to spray and mix the accelerators into the base print material may ensure homogeneous mixing of the accelerators and the base print material as the particles that come out of the injector (6) are small and penetrate the base print material and mix in multiple directions.

In an embodiment, multiple degrees of freedom of movement are configured to the printer (300). The mixing assembly (100) may rotate along the first longitudinal axis (A-A) and complex shapes or structures may be consequently printed. The extrusion head (4) may also be configured to rotate along the second longitudinal axis (B-B) and the different surface patterns may be imparted to the structures that are being extruded.

In an embodiment, the design of the mixing assembly (100) is simple, yet robust. In an embodiment, the mixing assembly (100) for the application of 3D Printing structures may provide a reliable system for addition of chemical admixtures such as accelerators to base print material prior to material extrusion and layering onto the print bed. The mixing assembly (100) provides a solution to the problems that are associated with the design and development of a system that addresses the subject of achieving high buildability of structures built using 3D Printing equipment and materials. Therefore, the mixing assembly (100) achieves homogeneous mixing of the accelerators into the base print material at close proximity to the extrusion head (4) and thus, prevents any premature hardening of the mixture (the base print material and the accelerator). Further, the print material extruded out of the mixing assembly (100) may provide physical structures that conform to build-worthiness, and thereby satisfy their pre-determined specifications for strength, stability, and durability.

Equivalents

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding the description may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated in the description.

Referral Numerals:

Description Referral numerals
First hose 1
Confluence chamber 2
Mixing portion 3
Extrusion head 4
Second hose 5
Injector 6
First inlet 7
Second inlet 8
Second motor 9
First motor 10
Second auger 11
Fourth motor 12
Third motor 13
First auger 15
Scrapper blade 16
Hopper 17
Inlet 18
Control unit 19
Solenoid valve 20
First conduit 21
Second conduit 22
Shaft 23a
Spiral extensions 23b
Bearing assembly 25
Mixing assembly 100
Printer 200
System 300
Method steps 301-306
,CLAIMS:We Claim:

1. A mixing assembly (100) for a three-dimensional printer (200), the mixing assembly (100) comprising:
a hopper (17) configured to receive and accumulate a base print material;
a first auger (15) defined within the hopper (17) and extending along a first longitudinal axis (A-A), wherein the first auger (15) mixes the base print material;
a confluence chamber (2) configured to receive the base print material from the hopper (17);
a second auger (11) defined within the confluence chamber (2) and extending along a second longitudinal axis (B-B) of the confluence chamber (2);
an injector (6) fluidly connected to the confluence chamber (2) for injecting an accelerator into the confluence chamber (2) during operation of the second auger (11); and,
an extrusion head (4) configured to the confluence chamber (2) for printing a mixture of the base print material and the accelerator.

2. The mixing assembly (100) as claimed in claim 1 comprising, a first motor (10) coupled to the first auger (15) for rotating the first auger (15) and directing the base print material from the hopper (17) to the mixing assembly (100).

3. The mixing assembly (100) as claimed in claim 1 comprising, at least one scrapper blade (16) fixedly connected to the first auger (15) and accommodated within the hopper (17) wherein, the scrapper blade (16) rotates with the first auger (15) for agitating and scraping the base print material from inner surfaces of the hopper (17).

4. The mixing assembly (100) as claimed in claim 1 comprising, a second motor (9) coupled to the second auger (11) for rotating the second auger (11) and for mixing the base print material with the accelerator.

5. The mixing assembly (100) as claimed in claim 1 wherein, the mixing assembly (100) is rotatably connected to the hopper (17) and, the mixing assembly (100) rotates along a first longitudinal axis (A-A) of the hopper (17).

6. The mixing assembly (100) as claimed in claim 5 comprising, a third motor (13) connected to the mixing assembly (100) for facilitating the rotation of the mixing assembly (100) along the first longitudinal axis (A-A).

7. The mixing assembly (100) as claimed in claim 1 wherein, the extrusion head (4) is rotatably connected to the confluence chamber (2) and, the extrusion head (4) rotates along the second longitudinal axis (B-B) of the mixing assembly (100).

8. The mixing assembly (100) as claimed in claim 1 comprising, a fourth motor (12) connected to the extrusion head (4) for facilitating the rotation of the extrusion head (4) along the second longitudinal axis (B-B).

9. The mixing assembly (100) as claimed in claim 1 wherein, the injector (6) is positioned at a predetermined angle with respect to a central axis (C-C) of the confluence chamber (2).

10. The mixing assembly (100) as claimed in claim 1 comprising, a solenoid valve positioned proximal to a region where the hopper (17) is fluidly connected to the mixing assembly (100) wherein, the solenoid valve closes when the printing is terminated and cuts off the flow of base printing material into the confluence chamber (2).

11. The mixing assembly (100) as claimed in claim 1 wherein, the solenoid valve terminates the operation of the injector (6) when the printing is terminated.

12. The mixing assembly (100) as claimed in claim 1 wherein, the injector (6) is positioned proximal to the extrusion head (4) and the base print material is mixed with the accelerators near the extrusion head (4).

13. A three-dimensional printer (200) comprising:
a hopper (17) configured to receive and accumulate a base print material;
a first auger (15) defined within the hopper (17) and extending along a first longitudinal axis (A-A) of the hopper (17), wherein the first auger (15) mixes the base print material;
the mixing assembly (100) fluidly connected to the hopper (17), wherein the mixing assembly (100) comprises:
a confluence chamber (2) configured to receive the base print material from the hopper (17);
a second auger (11) defined within the confluence chamber (2) and extending along a second longitudinal axis (B-B) of the confluence chamber (2);
an injector (6) fluidly connected to the confluence chamber (2) for injecting an accelerator into the confluence chamber (2) during operation of the second auger (11); and
an extrusion head (4) configured to the confluence chamber (2) for printing a mixture of the base print material and the accelerators;

14. The printer (200) as claimed in claim 13 comprising, a first motor (10) coupled to the first auger (15) for rotating the first auger (15) and directing the base print material from the hopper (17) to the mixing assembly (100).

15. The printer (200) as claimed in claim 13 comprising, at least one scrapper blade (16) fixedly connected to the first auger (15) and accommodated within the hopper (17) wherein, the scrapper blade (16) rotates with the first auger (15) for agitating and scraping the base print material from inner surfaces of the hopper (17).

16. The printer (200) as claimed in claim 13 comprising, a second motor (9) coupled to the second auger (11) for rotating the second auger (11) and for mixing the base print material with the accelerator.

17. The printer (200) as claimed in claim 13 wherein, the mixing assembly (100) is rotatably connected to the hopper (17) and, the mixing assembly (100) rotates along the first longitudinal axis (A-A) of the hopper (17).

18. The printer (200) as claimed in claim 17 comprising, a third motor (13) connected to the mixing assembly (100) for facilitating the rotation of the mixing assembly (100) along the first longitudinal axis (A-A).

19. The printer (200) as claimed in claim 13 wherein, the extrusion head (4) is rotatably connected to the confluence chamber (2) and, the extrusion head (4) rotates along the second longitudinal axis (B-B) of the mixing assembly (100).

20. The printer (200) as claimed in claim 19 comprising, a fourth motor (12) connected to the extrusion head (4) for facilitating the rotation of the extrusion head (4) along the second longitudinal axis (B-B).

21. The printer (200) as claimed in claim 13 wherein, the injector (6) is positioned at a predetermined angle with respect to a central axis (C-C) of the confluence chamber (2).

22. The printer (200) as claimed in claim 13 comprising, at least one solenoid valve positioned proximal to a region where the hopper (17) is fluidly connected to the mixing assembly (100) wherein, the solenoid valve closes when the printing is terminated and cuts off the flow of base printing material into the confluence chamber (2).

23. The printer (200) as claimed in claim 13 wherein, the at least one solenoid valve terminates the operation of the injector (6) when the printing is terminated.

24. The printer (200) as claimed in claim 13 wherein, the injector (6) is positioned proximal to the extrusion head (4) and the base print material is mixed with the accelerators near the extrusion head (4).

25. A method of printing material from a three-dimensional printer (200) with a mixing assembly (100), the method comprising:
loading and accumulating a base print material in a hopper (17);
directing the base print material through the hopper (17) by operating a first auger (15) accommodated within the hopper (17) and extending along a first longitudinal axis (A-A) of the hopper (17);
receiving by a confluence chamber (2), the base print material from the hopper (17);
injecting by an injector (6), an accelerator into the confluence chamber (2) wherein, the injector (6) is positioned proximal to an extrusion head (4);
mixing the base print material and the accelerator by operating a second auger (11) accommodated within the confluence chamber (2) and extending along a second longitudinal axis (B-B) of the confluence chamber (2);
printing by the extrusion head (4), the mixture of the base print material and the accelerator wherein, the injector (6) is positioned proximal to the extrusion head (4) and the base print material is mixed with the accelerators near the extrusion head (4).
Dated 09th day of December 2021



GOPINATH A S
IN/PA 1852
OF K&S PARTNERS
AGENT FOR THE APPLICANT