Cross Reference to Related Applications

[0001] This application claims priority of U.S. provisional patent application serial no.

61/970,577 filed on March 26, 2014 entitled FILAMENT FOR 3D PRINTER the disclosure of which is hereby incorporated herein by reference.

BACKGROUND

[0002] Additive manufacturing, also commonly referred to as 3D printing, is rapidly being adopted by both businesses and individuals. Users of 3D printing have many varied reasons for adopting this method of manufacture to replace or supplement more traditional forms of manufacture. The market for 3D printing equipment and supplies has become large and continues to grow.

[0003] The equipment used for 3D printing varies from small hobbyist machines to larger scale machines intended for relatively large production volumes. Several different types of such machines are known and widely used. One of the more common types utilizes an extrusion process when depositing material. Such machines commonly use filaments as a feedstock and are well-known to those having ordinary skill in the art. In such machines, a heated extrusion nozzle heats and deposits the filament to build the desired object. Examples of such machines are commercially available from MakerBot Industries.

[0004] A number of different filaments are available for use with 3D printers. The two most common materials used to form such filaments are polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). It is also known to incorporate additives in such filaments such as dyes or pigments to provide a desired color. Another example of a filament having an additive is a filament commercially available under the trademark Lay Woo-D3 and which is formed out of a polymer and a wood derived material.

[0005] While 3D printing technology has undergone notable improvements in recent years, further improvements remain desirable.

SUMMARY

[0006] The present invention provides a material for use in 3D printing that incorporates a soybean-derived product. The use of a plant based material enhances the sustainability of the material and provides an environmentally friendly material that can be used to create objects using additive manufacturing techniques.

[0007] The invention comprises, in one form thereof, a composition for building an object using an additive manufacturing process wherein the composition includes a soybean-derived material and a polymer.

[0008] In some embodiments, the soybean-derived material is approximately 20% to approximately 25% of the total composition by weight. The soybean-derived material may consists essentially of soybean oil. In other embodiments, the soybean-derived material is an acrylated epoxidized soybean oil.

[0009] In some embodiments, the polymer is polylactic acid (PLA). The composition may also include an additive.

[0010] The composition can advantageously be formed into an elongate filament.

[0011] The invention comprises, in another form thereof, a method of making a filament that includes the steps of mixing the soybean-derived material and the polymer together; and extruding the mixture of the soybean-derived material and the polymer to form the filament. In such a method, the step of extruding the mixture may include heating the mixture with the method further including quenching the extruded filament in a water bath after extruding the filament and subsequently coiling the filament before the filament has completely cooled.

[0012] The invention comprises, in yet other embodiments thereof, a method of using the composition that includes the step of forming the composition into pellets. When forming the composition into pellets, the method may further include melting the pellets and extruding the melted composition to form a filament. Such a method may also further include the step of adding an additive to the composition before extruding the melted composition to form the filament.

[0013] The invention comprises, in still another embodiment thereof, using the composition to build an object using an additive manufacturing apparatus.

[0014] The invention comprises, in yet a further embodiment thereof, an object made using the composition wherein the object is made using an additive manufacturing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above mentioned and other features of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a flowchart representing one method of forming a filament.

Figure 2 is a schematic representation of an extruder.

Figure 3 is a view of a coiled filament.

Figure 4 is a view of pellets which can be used as feedstock.

Figure 5 is a view of a spool with filament wound thereon.

Figure 6 is a cross-sectional view of a filament.

Figure 7 is a schematic representation of a three dimensional printer.

Figure 8 is a schematic representation of an object created with a three dimensional printer.

[0016] Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplification set out herein illustrates an embodiment of the invention, in one form, the embodiment disclosed below is not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise form disclosed.

DETAILED DESCRIPTION

[0017] A composition for building an object using an additive manufacturing process is disclosed herein. The composition includes a soybean-derived material and a polymer and can be advantageously formed into a filament. The filament can then be used in a conventional 3D printer or other suitable apparatus for forming the object using an additive manufacturing process.

[0018] FIG. 1 presents a flowchart representing the process for forming a filament out of the disclosed composition. FIG. 2 provides a schematic representation of a screw extruder 28 that can be used to form the filament 48. The composition is formed by mixing a soybean-derived material 30 and polymer 32 as represented by box 20 in the flowchart of FIG. 1. In the illustrated embodiment, the soybean-derived material 30 is an acrylated epoxidized soybean oil and polymer 32 is PLA in the form of raw polylactide pellets.

[0019] Acrylated epoxidized soybean oil is a known derivative of soybeans and a description thereof can be found in U.S. Pat. No. 3,931,075 issued Jan. 6, 1976; U.S. Pat. No. 4,233,130 issued Nov. 11, 1980; and U.S. Pat. No. 7,799,895 B2; the disclosures of which are all hereby incorporated herein by reference. In the illustrated embodiment, the acrylated epoxidized soybean oil is a commercially available epoxidized soybean oil tetra acrylate sold under the brand name Ebecryl ^® 860 by Allnex S.a.r.l. headquartered in Luxembourg. In alternative embodiments, a pure soybean oil could be used instead of an acrylated epoxidized soybean oil. In the illustrated embodiment, polymer 32 is PLA. Other polymers, however, could alternatively be mixed with the soybean-derived material, such as ABS or other suitable polymer.

[0020] When combining the soybean-derived material 30 and the polymer 32 at ambient conditions, the soybean-derived material 30 will typically be a liquid and the polymer 32 a solid in the form of pellets. When extruding small scale batches, the desired quantities of soy product 30 and polymer pellets 32 can be mixed to form liquid coated pellets prior to feeding the combined materials to extruder 28. For commercial production, it will most likely be advantageous for the process of feeding the two separate material streams into the extruder to be automated. If desired, an additive, such as a dye or pigment, could also be added to the composition.

[0021] In the schematic representation of FIG. 2, feed materials 30, 32 are added to hopper 34 which, in turn, feeds the mixture of material into a barrel housing a screw. The screw is driven by mechanism 36. A heating element 38 is used to heat the barrel and, thus, heat the combined materials into a molten mix. The molten final composition is then extruded through nozzle 40. The operation of extruder 28 is controlled using control panel 42. In the flowchart of FIG. 1, the step of extruding the combined materials after they have been heated is represented by box 22.

[0022] Nozzle 40 is configured to provide the desired shape and diameter of the filament which are suited to meet the specifications of the 3D printer. The temperature of extrudate is maintained a level that allows for a steady stream of material to be extruded to thereby provide a consistent product while maintaining the temperature below the molding temperature to avoid consumption of the composition. The two feedstocks are heated and mixed sufficiently to provide a homogenous composition before extrusion.

[0023] The illustrated embodiment uses a composition that is formed out approximately 25% (by weight) of an acrylated epoxidized soybean oil and approximately 75% (by weight) of PLA. The extrusion temperature is 375°F (190.6 °C) with the composition being extruded to form a elongate filament having a diameter of approximately 1.7 mm. The filament can be extruded into various cross-sectional shapes and diameters to adapt the filament for use in different 3D printing apparatus including the two most common filament diameters used in 3D printing apparatus, i.e., filaments having a nominal diameter of 1.7 mm and 3 mm.

[0024] In the illustrated embodiment, the extrudate 46 is introduced into a water bath 44 to cool extrudate 46. In the flowchart of FIG. 1, this step is represented by box 24. When forming a filament 48, the next step is represented by box 26 in the flowchart of FIG. 1 and involves coiling the filament before it has completely cooled.

[0025] Generally, it will be desirable to coil the filament to provide for convenient handling of the filament. It is advantageous to coil the extrudate before it completely sets. If the filament completely sets before coiling, it may be difficult to form into a coil. It will also be

advantageous for the extrudate to cool sufficiently so that the exterior surface of the extrudate is no longer tacky before it is coiled otherwise adjacent strands of the coiled filament could potentially adhere together. The time periods and temperatures at which the filament will lose its tackiness and fully set will vary depending on the make-up of the composition used to form the filament. After the coiled filament has fully cooled and set, the finished product is a ready-to- use 3D printer filament.

[0026] As mentioned above, the composition used to form filament 48 may be approximately 20-25% (by weight) soy-based materials with the illustrated embodiment having approximately 25% acrylated epoxidized soybean oil. If a pure soybean oil were used instead of the acrylated expoxidized soybean oil, a slightly smaller percentage, e.g., 20% by weight, of 100% soybean oil would be more suitable. The use of excessive percentages for the soy-based product can result in a filament having a tacky exterior surface.

[0027] Generally, all or substantially all of the remainder of the composition will be a polymer. In other words, if the soybean-derived material is 25% of the composition, all or substantially all of the remaining 75% will be a polymer such as PLA. In some instances a small quantity of an additive, such as a dye or pigment, might be added to the composition, however, in such situations, substantially all of the remainder of the composition will still generally be a polymer. The remainder will typically be a single polymer, however, a blend of two or more polymers could be used instead. Although it is not likely to be generally desirable, in some applications, it might also be desirable for the remainder of the composition to include to use a relatively significant quantity of a non-polymer material such as a filler. [0028] The use of smaller percentages of the soybean derived product in the composition can also be used. One of the advantages of the composition disclosed herein is that the use of a soybean derived material allows for a reduction in the amount of the other polymer used in the composition. Although there is no lower limit to the amount of soybean-derived material in the composition, reducing the amount of soybean-derived material in the composition lessens this generally desirable reduction in polymer usage.

[0029] Oftentimes, filaments for 3D printers are wrapped on spools with the 3D printers being adapted to have the spools removably mounted thereon to allow for the convenient loading of filaments on the 3D printer and easy feeding of the filament to the nozzle of the printer. FIG. 5 illustrates filament 48 wrapped on a spool 52 for a 3D printer. The use of such spools is well known in the art. One example of a suitable spool is illustrated in U.S. Pat. No. D705,643 S which issued on May 27, 2014.

[0030] Instead of forming a filament 48, the composition of soybean-derived material and polymer could, instead, be used to form pellets 50 as schematically depicted in FIG. 4. Such pellets could be formed by extruding the composition and cutting the extrudate into pellet length sections or other suitable manufacturing method. These pellets could then be used in a subsequent extrusion process to form a filament for a 3D printer or another form of feedstock for 3D printer. For example, pellets formed out of approximately 25% (by weight) acrylated epoxidized soybean oil and approximately 75% (by weight) PLA could be furnished to a manufacturer who then uses the pellets to extrude filaments. When using the pellets to form a filament, it may be advantageous to add an additive to the composition before extruding the filament.

[0031] Such additives might take the form of a dye or pigment to control color of final product. Other types of additives such as an inert filler material such as calcium carbonate, silica or clay might also be desirable in some applications. Another example of a potential additive is ground wood. For example, one known filament which adds ground wood to conventional polymers is commercially available under the name LAYWOO-D3 and can be used to simulate a wood product.

[0032] FIG. 6 illustrates another potential alternative use of the composition to form a filament for a 3D printer. In this embodiment, filament 54 is a bipart filament with a core 56 formed out of a first material and an outer sheath 58 formed out of a second material. A composition that includes a soybean-derived material and a polymer could be used to form either the inner core 56 or outer sheath 58 of such a filament. Various other uses of the composition to form filaments or other 3D manufacturing feedstocks are also possible.

[0033] FIG. 7 schematically depicts the use of an additive manufacturing apparatus / 3D printer 60 to form an object 70 using a filament 48 that is formed out of a composition that includes a soybean-derived material and polymer. The use of filaments in 3D printers is well known in the art and involves heating the filament and extruding it a second time to form the desired object.

[0034] Additive manufacturing apparatus 60 shown in FIG. 7 is a conventional 3D printing apparatus that includes a positioning system 62 which controls the position and movement of extruder and heating element 64. Positioning system 62 controls the position at which the reheated filament 48 is deposited to form part of the object in a three-dimensional space and is oftentimes referred to as an x-y-z positioning system although it may alternatively use a polar coordinate or other suitable coordinate system to control the location of the deposited material.

[0035] The object 70 being made is supported on a build platform 68 that, in some apparatus, includes a thermal control system. A 3D model of the object to be built is communicated to controller 66 which is used to control the operation of the apparatus 60. Although controller 66 is depicted as a single component, it may take the form of multiple processing units that are in communication with apparatus 60. A spool 52 with filament 48 feeds heated extruder 64 with material for forming object 70.

[0036] The feed-rate of filament 48 and temperature of the extrusion heating element are controlled by controller 66 which are factors that can affect the physical properties and color of the material in final product 70. As depicted in FIG. 8, the final product 70 in illustrated embodiment is a chess piece. Although a single built object 70 is illustrated, an almost limitless number of different types of objects can be made using an additive manufacturing process as described herein as will be understood by those having ordinary skill in the art.

[0037] It is further noted that the depicted apparatus 60 is a relatively simple apparatus and filament 48 may be used in more complex apparatus. For example, filaments 48 may be used in apparatus having multiple extrusion nozzles with each nozzle being fed by a different filament spool this allows the printer to quickly switch between filaments having different properties, such as different colors or different physical properties. An example of such an apparatus is described in U.S. Pat. No. 8,512,024 B2 issued on Aug. 20, 2013, the disclosure of which is hereby incorporated herein by reference.

[0038] The use of a 3D printing filament that is formed out of a composition that includes a soy-derived material and a polymer can be beneficial in many applications. For example, the melting temperature of soy-derived materials are generally lower than polymers commonly used to form 3D printing filaments. A lower melting temperature means that the extrusion temperature can also be lower. This can provide a reduction in energy usage.

[0039] A filament formed out of PLA and an acrylated epoxidized soybean oil as disclosed herein will have a higher Young's modulus than a similar filament made out of pure PLA. The higher Young's modulus means that the filament, and objects made out of that filament, will be more rigid than a similar filament or object made out of pure PLA. In many situations, this will be beneficial. It is further noted that the physical properties of the filament 48 is subject to some adjustment by adjusting the percentage of the soybean-derived material present in the composition used to form the filament as well as by adjustment of the polymer selected, or mix and ratio of selected polymers, and potential use of additives.

[0040] Because the soybean-derived material is derived from plant material it provides an environmentally-friendly material and facilitates sustainable manufacturing practices.

[0041] While 3D printing filaments 48 formed out of a soybean-derived material and polymer can provide many benefits as discussed above, pellets 50 formed out of such material may also provide useful feedstock for other applications in the plastic/ thermoplastic industry.

[0042] While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles.