An adaptable extrusion system for 3D printing

Abstract

The invention provides for an extrusion system which is applicable for use in additive manufacturing. This invention would show primary application for printing metal parts, but the scope of this invention is by no means limited thereto. The extrusion system is made up of a feedstock housing which defines a housing wall and a housing chamber which contains the filament-based feedstock. The housing wall contains a heating system which both heats and monitors the temperature of the feedstock so that the same is maintained at the predefined and optimum temperature prior to and during printing. The feedstock housing is in communication with an extrusion head the extrusion head defining a nozzle with an orifice for the extrusion of the feedstock on to a three-dimensional printer build plate. The extrusion system is removably attachable to a motion system of the 3D printer which motion system actuates the movement of the extrusion system in accordance with a print plan.

Description

AN ADAPTABLE EXTRUSION SYSTEM FOR 3D PRINTINGFIELD OF THE INVENTION

[0001] The present invention relates to three-dimensional (3D) printing. The present invention particularly relates to an adaptable extrusion system for 3D printing. In particular, the present invention relates to an adaptable extrusion system with variety of build volume for 3D printing process.BACKGROUND TO THE INVENTION

[0002] Three-dimensional printing (3D), also known as additive manufacturing, has been well known since the 1980’s. It has been and is currently being used in a vast range of fields, for instance, in the manufacturing of medical and / or dental implants, in the manufacturing of replacement parts and new parts in the automotive industry and, in the prototype construction, to name just a few examples. 3D printing is a process in which a 3D object is constructed or created using a printing plan to direct the extrusion of feedstock layer by layer to form the final printed object. Some of the well-known feedstock materials for 3D printing include thermoplastic materials e.g., Acrylonitrile Butadiene Styrene (ABS) plastic filaments, Polylactic acid (PLA) plastic filaments, metal powders, UV-cured resins, polyamide nylons, etc. Metal 3D printing media typically contains metal powder, either loose or as a bound metal powder that can be used as a base.

[0003] 3D printing is advantageous as in many instances it is economical and less timing consuming than conventional methods of producing protypes, spares and / or parts as no tools are required. Furthermore, compared to the traditional formative or subtractive manufacturing techniques, additive manufacturing can be used to produce lightweight and stable structures with high functionality, as well as customized structures in small series. The use of 3D printing in the manufacture of metal parts (e.g., forming tools, dies, nozzles etc.) is promising with an estimated short-termmarket value of over USD 10 billion and an expected growth rate of 30% each year. Stamped metal parts are typically steel parts, although other metals such as copper, titanium, tungsten carbide, and others can also be used.

[0004] In general, the printing process consists of developing a print plan (model) and cutting the model using software that facilitates the layering of the raw material onto the build plate after extrusion. Then the printed object is removed from the build plate and is either ready for use or require post-printing treatment before use. Reprinting steps can include curing, polishing, coating, and removing unused raw materials.

[0005] When metal objects are printed, the raw material can be metal powder (as shown in US20200324337A1 ), molten metal (as shown in WO2022104122 A1 ) or metallic ink (as shown in CA2976782 A1 ). Metal powder is by far the most common raw material of the above. However, metal powder is hazardous and difficult to handle, requiring special handling and processing techniques to reduce risks to the printer operator, which can include dust explosions and metal fires. A number of techniques have been developed to solve these problems. However, these methods do not eliminate the above risks or involve significant costs, which is undesirable. For example, the printing process can be performed in a vacuum, which solves the problems associated with using solid metal, but unfortunately significantly increases the costs associated with printing.

[0006] Examples of processes used to print metallic components may include: i. Powder bed fusion techniques that melt using a loose metal powder feedstock and a source of heat to fuse the same. Examples of powder bed fusion include “Selective Laser Melting”, (SLM), “Selective Laser Sintering”, (SLS), “Direct Metal Printing”, (DMP), and “Laser Powder Bed Fusion”, (LPBF). The commonly employed heat source is a laser but in more advanced techniques, heat may be provided by a beam of electrons (Electron Beam Melting). ii. Direct Energy Deposition (DED) refers to a category of 3D printing techniques in which a powder (powder DED) or wire (wire DED) is coaxially fed to a heat source to fuse the material during deposition. The document I N202117056661 A discloses DED is preferentially conducted inan enclosed manufacturing chamber filled with inert gas. The use of a chamber and the loss or waste of metal powder during the dispensing of the same affect the costs associated with this technique. iii. Binder Jetting: In this technique, loose metal powder is employed, but in addition to the deposition phases when the powder is placed on the build plate, a liquid binder is sprayed into the bed of powder, results in hardening the cross section of the printed object, layer by layer. The price of using this procedure includes the cost of the liquid binder as well as any potential removal expenses for unsolidified powder. The unsolidified electricity on the other hand is hazardous to the user. iv. Bound Powder Extrusion (BPE), a relatively recent technology in the sector, is preferred since it is safer (and hence more suitable for offices) because the metal powder is bound into a binder system that can be handled safely. The binding system which is generally polymeric has three main components: a. the main binder component that constitutes the majority of the binder; b. the backbone that serves to hold and maintain the shape of the printed object throughout the printing, subsequent washing, and thermal de-binding; and c. additives like dispersant agents, tackifiers, compatibilizers, and stabilizers that aid to disperse the filler particles in the polymeric binder, prevent agglomeration and phase separation and to assist with adhesion between the printed layers.

[0007] BPE and FFF which are closely related, have several advantages as the fact that they are easy to use with a variety of materials and object geometries. They can also be used with open cell infill and used in large or small building spaces.

[0008] In BPE, the bound metal powder is selectively extruded layer by layer on to the build plate through a nozzle. Extrusion requires pressure to be applied to the feedstock to force the same through the nozzle. A mechanical drive system is used to apply this pressure and this mechanical drive system may be plunger-based, filament-based, or screw-based. The filament-based extrusion, as described in one of the embodimentsof the present invention, operates in the mechanical drive system consisting of drive motors which force the filament through the nozzle.

[0009] To facilitate extrusion the feedstock must be maintained in a flexible condition while maintaining tensile strength. If the feedstock is allowed to cool it becomes brittle and breaks resulting in wasted material, longer print times and additional costs. Although the use of elastomers in the feedstock assists in maintaining the flexibility and flow rate of the same, the feedstock is also maintained at a constant and predetermined temperature in a feedstock chamber prior to extrusion. In many printers, the feedstock chamber is large, and the entire chamber must be heated, which adds to the concomitant costs.

[0010] Once the printing is completed the binding system is dis-bounded from the so- called “green part” (which contains the metal powder evenly distributed in the waxy polymer) by catalytic extraction, solvent extraction, or thermal de-binding. Complete de-binding is very important as residues from incomplete de-binding can influence the efficacy of sintering. Following de-binding the layers of extruded feedstock are sintered to fuse the same to each other. Sintering results in the slight shrinking of the printed object due to the removal of the binding system, reduction in porosity of the metallic component and densification of the part. Additional post- printing steps after sintering may be desired dependent on the application of the printed part and may include improvement of surface texture, accuracy, aesthetics, and a matte surface finish, to name but a few. A diagrammatic representation of shaping and then subsequent de- binding and sintering is given in Figure 1 (prior art).

[0011] As apparent to a person skilled in the art, a handful of companies use BPE commercially for 3D metal printing, including “Desktop Metal” (Bound Metal Deposition), “Marked Forged” (Atomic Diffusion Additive Manufacturing) and 3D Gence. The solutions offered by these companies are predominantly used in the production of steel parts and are cheaper than metal powder-based manufacturing, but more expensive than conventional fused deposition modeling and require extensive testing of produced parts prior to the inception of mass manufacturing of the same. Furthermore, the 3D printing systems used by these companies are only able to utilize BPE compatible materials limiting the application of the same. Given that theprinters used in these systems are specifically designed to deal with the specific needs of BPE such as ambient temperature and improved extrusion they are also significantly more expensive than generic FFF printers although cheaper than other types of metal 3D printing.

[0012] To reduce costs, the costs of printing metallic parts it would be advantageous to provide for a retrofit solution that can be installed on a 3D printer, such that an adaptable extrusion system can be developed with variety of build volume for 3D printing process.OBJECT OF THE INVENTION

[0013] It is, therefore, an object of the present invention to provide an extrusion system which, at least in part, ameliorates the challenges associated with the known extrusion systems and to provide a retrofittable component to allow for an adaptable extrusion system with variety of build volume.SUMMARY OF THE INVENTION

[0014] Accordingly, as per one aspect of the present invention there is provided an extrusion system, configurable in 3D printers, including: an extrusion head through which feedstock utilized in additive manufacturing is operationally extruded; and a feedstock housing defining an interior filament enclosure functioning to contain the feedstock and to allow for heat exchange and flux prior to the extrusion of the feedstock;an automatic atmospheric controller switch to control constant temperature within the extrusion system; wherein the extrusion system is removably attachable to a motion system of a three- dimensional printer such that, the feedstock housing is arrayed to secure a minimal interspace between feedstock stock storage and extrusion head.

[0015] It will be appreciated by a person skilled in the art that the extrusion head, feedstock housing with interior filament, the automatic atmospheric controller, and the motion system, may be separate components that can be sold separately or in the form of a kit for assembly by a user. It will be further appreciated that the extrusion system may be sold fully assembled for retrofitting to a 3D printer or already incorporated and attached to such printer.

[0016] In another aspect of the present invention, the interior filament enclosure is located within a housing compartment that has a regulating system located therein. The regulating system functions to heat the feedstock and maintain the same at a predetermined interior ambient condition prior to extrusion.

[0017] In another aspect of the present invention, the heating system includes a heat source and a heat sensor, the heat source functioning to heat the compartment, housing chamber and the feedstock contained therein, and the heat sensor is functioning to measure the temperature of the feedstock and regulate the temperature of the heat source such that the temperature of the feedstock is maintained as constant wherein the minimal interspace between feedstock stock storage and extrusion head is maintained in the extrusion system.

[0018] In another aspect of the present invention the feedstock is maintained at a temperature of about 40°C to 200°C, wherein the temperature is determined in accordance with the physiochem ical properties of the feedstock with respect to printing with the same.

[0019] In another aspect of the present invention, the interior ambient conditions may include specific humidity.

[0020] In another aspect of the present invention, the heat source is electrically controlled via a switch which is operational via direct current (DC) alternatively, alternating current (AC).

[0021] In another aspect of the present invention, the heat source is in fluid communication with a conduit which in turn is in fluid communication with a splitter, the heat distributor and splitter functioning, in use, to provide for the even distribution of heat across the surface of the feedstock.

[0022] It will be appreciated by a person skilled in the art, that where the temperature of the feedstock is required to be increased, the switch will be electrically activated and where the temperature of the feedstock is required to be reduced, the switch will be deactivated, thereby allowing for the regulation of the heat source in response to temperature signals received from the heat sensor. Alternatively, if the temperature of the feedstock is too high the same can be actively cooled by the activation of the cooling source at the same or alternate times to the deactivation of the heat source.

[0023] It will be appreciated by a person skilled in the art that the heat source may include but not be limited to heating pads; a heat gun; fluid-based heating sources such as piped water, air, or steam; laser facilitated heating, electron beam facilitated heating, chemically facilitated heating etc.

[0024] In another aspect of the present invention, the heat source is in fluid communication with a heat distributor which in turn is in fluid communication with a splitter.

[0025] In another aspect of the present invention, the motion system comprises one or more linear guide rails in slidable communication with one or more guide blocks.

[0026] In another aspect of the present invention, the aforesaid one or more guide blocks to which the extrusion system is attached, the guide blocks operationally moving along the linear guide rails, thereby facilitating the movement of the extrusion system in accordance with the print plan.

[0027] It will be appreciated by a person skilled in the art that single and dual motion systems may be envisaged such that the extrusion system and more particularly the feed stock housing of the same may be mounted on two guide blocks which are slidably moveable along a plurality of linear guide rails. Furthermore, a dual system is preferable, but not limited, given that this provides for the distribution of load as regards to the extrusion system described herein.

[0028] In another aspect of the present invention, the extruder head defines an interior channel through which the feedstock flows operationally.

[0029] In another aspect of the present invention, the feedstock housing defines a housing wall and a housing chamber, the housing chamber functionally containing the feedstock to be dispensed and the housing wall containing a heating system for heating the feedstock.

[0030] In another aspect of the present invention, the feedstock housing is connectable to safety cutoffs that allow for the termination of electric current to the switch in the event that the temperature in the chamber exceeds a predetermined maximum allowable temperature, alternatively, that allows for fusing of the switch in the event of overcurrent supply.

[0031] It will be appreciated by a person skilled in the art that both types of safety cut offs function to protect the extrusion system from critical damage that may compromise the lifespan of the same or the three-dimensional printer to which the same is fitted. This type of conservation of machinery is fundamental in the art given that printers and printer parts are expensive to replace and where replacements are required there are additional costs incurred with respect to printer downtime. Furthermore, these safety cutoffs are also essential with respect to providing safe operating conditions for the operator.

[0032] In another aspect of the present invention, the interior channel has a first terminus and a second terminus which are diametrically opposed to each other, the first terminus being in communication with the chamber and the second terminusdefining a nozzle with an orifice through which the feedstock flows during printing. In another aspect of the present invention, the extrusion system is fitted with one or more drive gears located posteriorly in relation to the feedstock housing and functioning, in use, to actuate the flow of the feedstock within the interior channel and out of the nozzle.

[0033] In yet another aspect of the present invention, the drive gear is a thin flat toothed gear that functions in use to push the feedstock which is a filament down through the extruder. The drive gear or gears engage with a stepper motor which provides the correct pressure to define the required extrusion rate.

[0034] It will be appreciated by a person skilled in the art that the extrusion system may be fitted with a single drive gear, alternatively dual drive gears or combination of variety of drive gears. For the purposes of this invention dual drive gears is the preferred example embodiment.

[0035] In yet another aspect of the present invention, the feedstock may be a bound metal powder, alternatively a polymeric feedstock, further alternatively a ceramic feedstock although that in a preferred example embodiment of the invention the feedstock is a bound metal powder and filament based.

[0036] In yet another aspect of the present invention, the heat distributor is a fan that actuates the movement of hot air into the housing chamber thereby providing for the heating of the feedstock. The air splitter provides an even distribution of hot air across the surface of the feedstock.

[0037] In yet another aspect of the present invention, the airflow rate applied by the fan will be between about 5000 rpm to about 15000 rpm.

[0038] In yet another aspect of the present invention, the air splitter and fan additionally provide a port for the prevention of an airlock being operationally induced in the housing chamber.

[0039] In yet another aspect of the present invention, the switch actuating the heat source may be encoded for using G-code which is set by the material supplier or printer user.

[0040] In yet another aspect of the present invention, the switch is a MOSFET switch, alternatively a solid-state relay.

[0041] In yet another aspect of the present invention, the extruder system is removably attachable to a three-dimensional printer and lockable thereto in an operational configuration through the action of a lock located on the feedstock housing.

[0042] It will be appreciated by a person skilled in the art that the lock may include but not be limited to a latch, a lever, a clip etc.

[0043] In yet another aspect of the present invention, the motion system is actuated upon the commencement of printing via a main print control switch which also functions to actuate the heating of the heating source which heats the feedstock.BRIEF DESCRIPTION OF THE DRAWINGS

[0044] These and other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

[0045] Figure 1 is a diagrammatic representation of the shaping, de-binding and sintering processing steps that are applied in the art (prior art).

[0046] Figure 2 is a perspective view of the extrusion system in accordance with one the embodiments of the invention.

[0047] Figure 3 is another perspective view of the extrusion system in accordance with one the embodiments of the invention.

[0048] Figure 4 is a perspective view of the extrusion system of Figure 2 wherein the feedstock housing is in an open position in accordance with one of the embodiments of the invention.

[0049] Figure 5 is another perspective view of the extrusion system Figure 3, wherein the feedstock housing is a two-way open position in accordance with one of the embodiments of the invention.

[0050] Figure 6 is a perspective top view of the extrusion system in accordance with one of the embodiments of the invention.

[0051] Figure 7 is a cross sectioned view of an extrusion system of the invention having a single motion system in accordance with one of the embodiments of the invention.

[0052] Figure 8 is a cross sectioned view of an extrusion system of the invention having a dual motion system in accordance with one of the embodiments of the invention.

[0053] Figure 9 is a top view of the extrusion system of Figure 8, in accordance with one of the embodiments of the invention.

[0054] Figure 10 is an exploded view of the extrusion system, in accordance with one of the embodiments of the invention.

[0055] Figure 11 is an internal view of the extrusion system showing a spooled filament, in accordance with one of the embodiments of the invention.

[0056] Figure 12 is a circuit diagram for the circuitry applied to the invention, in accordance with one of the embodiments of the invention.DETAILED DESCRIPTION OF INVENTION

[0057] The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which forms a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions, or parameters described and / or shown herein and that the terminology used herein is for the example only and is not intended to be limiting of the claimed invention.

[0058] Also, as used in the specification including the appended claims, the singular forms ‘a’, ‘an’, and ‘the’ include the plural, and references to a particular numerical value includes at least that particular value unless the content clearly directs otherwise. Ranges may be expressed herein as from ‘about’ or ‘approximately’ another particular value when such a range is expressed another embodiment. Also, it will be understood that unless otherwise indicated, dimensions and material characteristics stated herein are by way of example rather than limitation and are for better understanding of sample embodiment of suitable utility, and variations outside of the stated values may also be within the scope of the invention depending upon the particular application.

[0059] Embodiments will now be described in detail with reference to the accompanying drawings. To avoid unnecessarily obscuring the present disclosure, well-known features may not be described or substantially the same elements may not be redundantly described, for example. This is for ease of understanding.

[0060] The following description is provided to enable those skilled in the art to fully understand the present disclosure and are in no way intended to limit the scope of the present disclosure as set forth.

[0061] Embodiments described herein provide an adaptable extrusion system, configurable in 3D printers of variety of build volume.

[0062] Referring to figures 2 to 11 which show an extrusion system (10) in accordance with the invention and Figure 12 shows the circuitry for the same.

[0063] According to one the embodiments, Figure 2 represents a perspective view of the extrusion system (10), which is implemented in additive manufacturing in 3D printing; includes the feedstock housing (14), a motion system (16) with one or more guide blocks (68) and has a housing body (44) which has two parts an upper (44a) and a lower part (44b) that are hingeably attachable to each other. The housing body (44) needs to be maintained in a closed position and hence the same is fitted with a latch lock with handle (56) which holds the same in the closed position. The housing body (44) is hingeably accessible in that it is fitted with a hinge (52) that allows for the opening of the housing body (44) the upper part (44a) moving away from the lower part (44b) upon opening.

[0064] According to one of the embodiments, Figure 3 represents another perspective view of the extrusion system (10) with a variation of a Bowden filament channel (39) for directing filament towards an extrusion head (12), a sealing frame element (41 ) to provide soft sealing to prevent any possible air and temperature leakage, temperature and humidity sensor (47), and air vent cover (37).

[0065] According to the one embodiment, the extrusion system (10) represented in both the perspective view in Figure 2, 3 and 4, is applicable in additive manufacturing in 3D printing, includes an extrusion head (12), a feedstock housing (14) and a motion system (16). The feedstock housing (14) operationally contains the feedstock (18) in a housing chamber (20) and the extruder head (14) provides the mechanism for the extrusion of the feedstock (18) on to a build plate (22) layer by layer in accordance with a print plan to create the printed object (not shown). The motion system (16) moves the extruder head (12) in accordance with the print plan and a minimal interspace between feedstock stock storage and extrusion head (12) is maintained in the extrusion system (10).

[0066] According to one of the embodiments, Figure 4 represents a perspective view of the one-way open position of the extrusion system (10). Figure 4 represents the feedstock housing (14) has a housing body (44) which has two parts an upper (44a) and a lower part (44b) that are hingeably attachable to each other with a latch lock handle (56). The housing body (44) defines a housing wall (46), the housing chamber (20) and a compartment (48) between the housing wall (46) and the housing chamber(20). The housing chamber (20) functionally contains the feedstock (18) to be extruded and the remainder of the housing body (44) contains a heating system which functions in use, to heat the feedstock (18) and maintain the same at a predetermined heat prior to extrusion. The housing body (44) is hingeably accessible in that it is fitted with a hinge (52) that allows for the opening of the housing body (44) the upper part (44a) moving away from the lower part (44b) upon opening. Opening allows a user access to the housing chamber (20) for the purposes of loading the feedstock (18). According to another embodiment of the present invention, a seal (54) may be located between upper (44a) and lower parts (44b) of the housing body (44) and would function to create a tight seal between the two (44a; 44b) or three parts (44a; 44a; 44b) to prevent the loss of heat from the compartment (48) in the closed position. The extruder head (10) defines an interior channel (34) through which the feedstock (18) operationally flows. The interior channel (34) has a first terminus (36) and a second terminus (38) which are diametrically opposed to each other. The first terminus (36) is in communication with the housing chamber (20) which contains the feedstock (18). The second terminus (38) terminates in a nozzle (40) which has an orifice through which the feedstock (18) flows during printing. The rotatable spool (24) is rotatable due to the action of a rotation system (26) which would include a spindle (28), drive motors (not shown) in contact with bearings (30) and a spindle seat (32) to drive the rotation of the rotatable spool (24) upon activation of printing.

[0067] According to one of the embodiments, Figure 3 represents the extruder head (12) with variation of Bowden interior channel (39), which represents another variation of the interior channel (34) through which the feedstock (18) operationally flows. The Bowden filament channel (39) directs filament towards the extruder head (12). Air flows into the feedstock housing (14) through a conduit which has air vent cover (37). A temperature and humidity sensor (47) is also located within the feedstock housing (14). The upper part (44a) and lower part (44b) of the feedstock housing (14) are sealed with sealing frame element (41 ) to prevent the heat and air leakage.

[0068] According to one of the embodiments, Figure 5 represents a perspective view of two-way open position of the extrusion system (10) with the components defined in detailed manner in the description of Figure 2 and 4 and the same is not repeated for the sake of brevity.

[0069] According to one of the embodiments, Figure 6 represents a top perspective view of the extrusion system (10). The subject invention relates particularly but not limited to FFF wherein, the feedstock (18) which is generally bound metal powder but may be polymeric or ceramic is a filament as is shown in Figures 6, 10 and 11. The feedstock (18) filament is generally spooled around a rotatable spool (24) which is rotatable about its central axis, and which successively unwinds during printing. The rotatable spool (24) is rotatable due to the action of a rotation system (26) which would include a spindle (28), drive motors (not shown) in contact with bearings (30) and a spindle seat (32) to drive the rotation of the rotatable spool (24) upon activation of printing.

[0070] Figure 7 is a cross sectioned view of an extrusion system of the invention having a single motion system in accordance with one of the embodiments of the invention.

[0071] Figure 8 is a cross sectioned view of the extrusion system (10) of the invention having a dual motion system and Figure 9 represents top view of the extrusion system (10) having dual motion system. The working of the motion system represented in Figure 7 and Figure 8 is described in detailed manner below.

[0072] It will be appreciated by a person skilled in the art that the motion system (16) may be attached to the extrusion system (10) or removably attachable to one or a number of parts thereof and / or sold as a kit for assembly by a print operator. It is contemplated that the extrusion system (10) of the invention will be designed so as to be retrofittable to 3D printers thereby allowing for a cheaper solution for printing with bound metal powders and lowering the costs associated with market entry in this industry given that BPE is more expensive than FFF.

[0073] According to another embodiment of the present invention, the extruder head (10) defines an interior channel (34) through which the feedstock (18) operationally flows. The interior channel (34) has a first terminus (36) and a second terminus (38) which are diametrically opposed to each other. The first terminus (36) is in communication with the housing chamber (20) which contains the feedstock (18). Thesecond terminus (38) terminates in a nozzle (40) which has an orifice through which the feedstock (18) flows during printing.

[0074] According to another embodiment of the present invention, the exploded view of the extrusion system (10) is represented by Figure no.10 wherein located posterior to the feedstock housing (14) are one or more drive gears (42) which actuate the flow of the feedstock (18) within the interior channel (34) and out of the nozzle (40) during printing. In the drawings dual drive gears are shown but it will be appreciated that various numbers of drive gears (42) could be used although that two are the preferred example embodiment. The interior channel (34) is held in compression by bearings (not shown) biased towards the interior channel (34) so as to prevent expansion of the same and deformation of the feedstock (18) within the interior channel (34).

[0075] According to another embodiment of the present invention, the Figure 11 represents the feedstock housing (14) has a housing body (44) which has two parts an upper (44a) and a lower part (44b) that are hingeably attachable to each other. The housing body (44) defines a housing wall (46), the housing chamber (20) and a compartment (48) between the housing wall (46) and the housing chamber (20). The housing chamber (20) functionally contains the feedstock (18) to be extruded and the remainder of the housing body (44) contains a heating system (50) which functions in use, to heat the feedstock (18) and maintain the same at a predetermined heat prior to extrusion. The housing body (44) is hingeably accessible in that it is fitted with a hinge (52) that allows for the opening of the housing body (44) the upper part (44a) moving away from the lower part (44b) upon opening. Opening allows a user access to the housing chamber (20) for the purposes of loading the feedstock (18). According to another embodiment of the present invention, a seal (54) may be located between upper (44a) and lower parts (44b) of the housing body (44) and would function to create a tight seal between the two parts (44a; 44b) to prevent the loss of heat from the compartment (48) in the closed position.

[0076] In an operational condition the housing body (44) needs to be maintained in a closed position and hence the same is fitted with a latch lock with handle (56) which holds the same in the closed position. The latch lock with handle (56), may be a latch,clip, a lever etc., with can enable the locking of the extrusion system can be held by hand, and the type of lock envisaged is by no means limited to these examples.

[0077] According to another embodiment of the present invention, the heating system (50) includes a heat source (58), a channel for the flow of air (air flow represented by arrows on the drawings) into the feedstock housing (14), a heat sensor (118) (usually a thermistor) and splitter (64) or diffuser. The heat source (58) functions to heat the housing chamber (20) and the feedstock (18) contained therein to a predetermined temperature so as to maintain the feedstock (18) in a flexible state prior to and during extrusion, thereby preventing the breaking of the same and associated print failure. It will be appreciated by a person skilled in the art that the heat source (58) may include but not be limited to heating pads, a heat gun (which could feed into and through the channel from an external source), a fluid-based heating source (piped water, air, or steam), laser facilitated heating, electron beam facilitated heating, chemically facilitated heating etc. The heat sensor (118) measures the temperature of the feedstock (18) and regulates the temperature of the heat source (58) such that the temperature of the feedstock (18) is maintained as constant.

[0078] According to another embodiment of the present invention, the heat system is electrically controlled via a switch (not shown) which is operational via direct current (DC) alternatively alternating current (AC). When the temperature of the feedstock (18) needs to be increased, the switch will be electrically activated and where the temperature of the feedstock is required to be reduced, the switch will be deactivated thereby allowing for the regulation of the heat source (58) in response to temperature signals received from the heat sensor (118). In a preferred example embodiment, the feedstock (18) is merely heated and not cooled as cooling happens passively when the heat sensor (118) deactivates the heat source (58) when the temperature rises above the predetermined required temperature.

[0079] It will be appreciated by a person skilled in the art that active cooling using a cooling system may also be applied. The envisaged electrical circuity with respect to the activation and deactivation of the heat source (58) is shown in Figure 12. As can be seen in the circuit diagram represented in Figure 12, printing is activated through the activation of a main circuit (100) which delivers an electrical signal that may becontrolled by pulse width modulation (PWM) (116) to a solid-state relay (112) or MOSFET (metal-oxide-semiconductor field -effect transistor) switch. The activation of the main circuit (100) will then activate the heating function (including heating sensor (118) and the movement of the motion system (16) either contemporaneously or successively once the feedstock (18) reaches the desired and predetermined printing temperature. The activation of the switch in response to the heat sensor (118) may be encoded for using G-code which is set by the material supplier or printer user.

[0080] According to another embodiment of the present invention, at the commencement and for the duration of printing the feedstock (18) is maintained at a temperature of about 40°C to about 200°C, preferably at a temperature of about 180°C to 260°C. The precise temperature applied and maintained is determined in accordance with the physiochemical properties of the feedstock (18) and the requirements for printing with the same.

[0081] According to another embodiment of the present invention, there is further provided that the heat source (58) is in fluid communication via the channel with a splitter (64). The heated air in a preferred example embodiment is distributed when air actuated by a fan (120) moves through the channel and the splitter (64) into the compartment (48) in a uniform manner distributing heat evenly around the compartment (48) and housing chamber (20). The splitter (64) facilitates the even distribution of the hot air within the compartment (48) which allows for even and constant heating of the housing chamber (20) to prevent thermal gradients developing within the feedstock (18). The airflow rate applied by the fan (120) is between about 5000 rpm to about 15000 rpm. It will be appreciated by a person skilled in the art that the heat source (58) may include but not be limited to heating pads, a heat gun, fluidbased heating sources such as piped water, air, or steam, chemically facilitated heating etc. In the accompanying drawings the heat source (58) is illustrated as heating pads.

[0082] It is critically important that the functionality of the printer be maintained in the event of electrical failure and hence the heating sensor (118) is connectable to safety cutoffs that allow for the termination of electric current to the switch if the temperature in the housing chamber (20) exceeds a predetermined maximum allowabletemperature. The switch can also be manufactured to allow for fusing in the event of overcurrent supply. An example of fusing in the event of overcurrent supply from main circuitry is shown in Figure 12.

[0083] Figure 12 illustrates the main circuit (100) that comprises: electrical socket plug (102) having fuse (104) connected through earth wire (106) to carry leakage current and prevents any damage to the circuit, neutral wire (108) to complete the flow of the circuit periodically connected with fuse (104) to provide protection against the overflow of current in an electrical circuit and live wire (110) to carry current to the extrusion system at a high voltage. The electrical socket plug is connected to solid state relay (SSR) (112) for turning on and off the main circuit (100) without physical contact and spark. The main controller (114) is connected to SSR (112) to control the temperature of the extrusion system and actuating the heating of the same via pulse-width modulation (PWM) controller (116) to modulate the electrical input supplied to the extrusion system. The main controller (114) is further connected to thermistor (118) to sense changes in temperature and change its resistance as temperature changes. The fan (120) is inputted with an SSR (112) and main controller (114) to the main circuit (100).

[0084] According to another embodiment of the present invention, the motion system (16) which is activated by a main print switch upon the commencement of printing comprises one or more linear guide rails (66) in slidable communication with one or more guide blocks (68). The extrusion system (10) is attached to the guide blocks (68) which typically contain internal bearings (not shown) and operationally move along the linear guide rails (66) in accordance with the print plan. It will be appreciated by a person skilled in the art that single (Figure 7) and dual (Figure 8) motion systems (16) may be envisaged such that the extrusion system (10) and may be mounted to two linear guide rails (66) and have more than one guide block (68). A dual system is preferable given that this provides for the distribution of load for the extrusion system (10).

[0085] According to another embodiment of the present invention, as discussed in detail above the invention as described ameliorates the costs associated with printing using bound metal powder. This cost reduction is facilitated by the fact that theinvention is not only retrofittable to an FFF printer (cheaper than BPE printers) but also that the housing chamber (20) that is to be heated is smaller than those on BPE printers (less energy required to heat and maintain feedstock temperature).

[0086] Finally, it will be appreciated by a person skilled in the art that a method that utilizes the extrusion system of the invention will also be incorporated within the scope of the invention as claimed herein.

[0087] Although certain representative embodiments and advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate when reading the present application, other processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the described embodiments may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

CLAIMS1. An adaptable extrusion system, applicable for use in 3D printing, comprising: an extrusion head through which feedstock utilized in additive manufacturing is operationally extruded; and a feedstock housing defining an interior filament enclosure functioning to contain the feedstock and to allow for heat exchange and flux prior to the extrusion of the feedstock; an automatic atmospheric controller switch to control constant temperature within the extrusion system; wherein the extrusion system is removably attachable to a motion system of a three- dimensional printer such that, the feedstock housing is arrayed to secure a minimal interspace between feedstock stock storage and extrusion head.

2. The extrusion system, as claimed in claim 1 , wherein the interior filament enclosure is located within a housing compartment which housing compartment has a regulating system located therein, the regulating system functioning, in use, to heat the feedstock and maintain the same at a predetermined interior ambient condition prior to extrusion.

3. The extrusion system, as claimed in claim 2, wherein the regulating system includes a heat source and a heat sensor; the heat source functioning to heat the housing compartment, the interior filament enclosure and the feedstock contained therein; the heat sensor functioning to measure the temperature of the feedstock and regulate the temperature of the heat source such that the temperature of the feedstock is maintained as constant.

4. The extrusion system, as claimed in any one of claims 1 to 3, wherein the feedstock is maintained at a temperature of about 40°C to 260°C, preferably at a temperature of about 180°C to 260°C.

5. The extrusion system, as claimed in claim 2, wherein the interior ambient conditions may include specific humidity.

6. The extrusion system, as claimed in claim 3, wherein the heat source is electrically controlled via a switch which is operational via direct current (DC) alternatively alternating current (AC).

7. The extrusion system, as claimed in claim 5, wherein the switch is a is an automatic atmospheric controller switch.

8. The extrusion system, as claimed in any one of claims 3 to 5, wherein the heat source is in fluid communication with a conduit which in turn is in fluid communication with a splitter and a heat distributor, the heat distributor and splitter functioning, in use, to provide for the even distribution of heat across the surface of the feedstock.

9. The extrusion system, as claimed in claim 1 , wherein the motion system comprises one or more linear guide rails in slidable communication with one or more guide blocks to which the system is attached.

10. The extrusion system, as claimed in claim 9, wherein the aforesaid one or more guide blocks to which the extrusion system is attached and which operationally move along the linear guide rails and thereby facilitate the movement of the extrusion system in accordance with the print plan.11 . The extrusion system, as claimed in claim 1 , wherein the extruder head which is in fluid communication with the interior filament enclosure defines an interior channel through which the feedstock flows operationally and a nozzle for the extrusion of the feedstock on to a build plate of a 3D printer.

12. The extrusion system, as claimed in claim 1 , wherein one or more drive gears and one or more idle gears are located posteriorly in relation to the housing and function, in use, to actuate the flow of the feedstock within the interior filament enclosure and out of the nozzle.

13. The extrusion system, as claimed in claim 1 , wherein the feedstock is held in compression by at least two bearings to maintain constant and / or uniform tension and grip on the feedstock.

14. The extrusion system, as claimed in claim 1 , wherein the feedstock is selected from the group comprising filament-based bound metal powder, polymeric feedstock, or ceramic feedstock.

15. The extrusion system, as claimed in claim 1 , applicable for use in 3D printers having a variety of build volumes.

16. A kit comprising: an extrusion head through which feedstock utilized in additive manufacturing is operationally extruded; a feedstock housing defining an interior filament enclosure functioning to contain the feedstock and to allow for heat exchange and flux prior to the extrusion of the feedstock; a switch to control and maintain constant ambient conditions within the extrusion system; and a motion system to functionally actuate the movement of the extrusion system in accordance with a print plan so as to facilitate printing of a three-dimensional printed object in accordance with the print plan,17. The kit, as claimed in claim 16, defining a retrofittable extrusion system for a 3D printer when assembled.

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