WO2023080903A1

WO2023080903A1 - Applying a polyamide composition to an object formed from additive manufacturing

Info

Publication number: WO2023080903A1
Application number: PCT/US2021/058401
Authority: WO
Inventors: Emre Hiro DISCEKICI; Shannon Reuben Woodruff; Greg Scott Long
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2023-05-11

Abstract

A method is provided comprising: providing a composition comprising a solvent and a polyamide; applying the composition to at least part of an object formed from an additive manufacturing process; and heating the object.

Description

APPLYING A POLYAMIDE COMPOSITION TO AN OBJECT FORMED FROM ADDITIVE MANUFACTURING

BACKGROUND

[0001] Additive manufacturing machines produce 3D (three-dimensional) objects by building up layers of material. Some additive manufacturing machines are commonly referred to as "3D printers ". 3D printers and other additive manufacturing machines make it possible to convert a CAD (computer aided design) model or other digital representation of an object into the physical object. The model data may be processed into slices each defining part of a layer or layers of build material to be formed into the object. Build material may be any suitable form of build material, for example fibres, granules or powders. The build material can include thermoplastic materials, such as polymers. An object manufactured using additive manufacturing processes may be treated or processed following its formation to impart properties or characteristics to the object. In some applications, additional strength, strain resistance, or resilience may be provided to an object, or part of an object, using such techniques.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Some non-limiting examples of the present disclosure will be described in the following with reference to the appended drawings, in which:

[0003] Figure 1 is an example of a method that may be used to strengthen at least part of an object formed from an additive manufacturing process;

[0004] Figure 2 is an example of a process that may form a coated article using three- dimensional printing; [0005] Figure 3 is an example of a non-transitory computer readable medium coupled to a computing device;

[0006] Figure 4 is a chart showing the experimental strain at break of objects according to various examples;

[0007] Figure 5 is a chart showing the experimental tensile strength and Young’s modulus of objects according to various examples; and

[0008] Figure 6 is a chart showing the experimental strain at break of objects according to various examples.

DETAILED DESCRIPTION

[0009] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilised and changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. Itt is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise.

[0010] Additive manufacturing systems such as 3D printers may utilise build material for the formation of 3D objects. In operation, die or multiple build materials may be deposited on a build surface of an additive manufacturing system and then fused or otherwise bound to form a desired 3D object. Polymers are one such category of build material suitable for the formation of a 3D object using an additive manufacturing system. Some three-dimensional objects may exhibit mechanical weakness in at least one direction following formation and there is a risk that further handling or processing may cause damage or breakage if such processes are not adequately monitored and controlled.

[0011] The methods and processes of the present disclosure may be used in conjunction with objects, articles, or products formed at least in part from an additive manufacturing process. For ease of reference, the term “object " will be used hereinafter to refer to any such object, article, or product and is intended to refer to any item created using an additive manufacturing process. In an example, the methods and processes of the present disclosure may be used in association with an object formed from a polymer build material. Polymer build materials that may be used to form three- dimensional printed objects for use in the present disclosure indude polyamides, polypropylenes, polyethylenes, polyethylene terephthalates, polybutylene terephthalates, polyoxymethylenes, thermoplastic polyurethanes, thermoplastic polyamides, any other suitable polymeric build material or combinations thereof. In an example, the build material used to form an object may indude a polyamide. In such an example, the build material may comprise thermoplastic polyamide (TPA). Where the build material indudes a polyamide, the polyamide may be crystalline or semi- crystalline. The polyamide material may have a processing window of greater than 5°C. The processing window of a material may be defined by the temperature range between the melting point and the re-crystallization temperature of the material. In an example, the polyamide material may have a melting point ranging from about 50°C to about 300°C. In other examples, the polyamide material may have a melting point ranging from about 155°C to about 225°C, from about 155°C to about 215°C, about 160°C to about 200’C, from about 170°C to about 190°C, or from about 182°C to about 189°C. As still another example, the polyamide material may have a melting point of about 180°C. Additive manufacturing processes may form an object by building a sequence of layers that combine to form the object Objects that may be used with the methods and processes of the present disclosure may be formed in any suitable manner. For example, the object may be printed in the x-, y-, or z-orientation. In one example, the object may be printed in the z-orientation. For the avoidance of doubt, an object printed in the z-orientation is formed by depositing at least one layer of build material in a plane that is parallel, or substantially parallel, with the base of the build area of an additive manufacturing apparatus and/or a plane that is perpendicular, or substantially perpendicular to the direction of gravity.

[0012] Some of the examples of the methods and processes disclosed herein indude the formation of an object via an additive manufacturing process. In other examples, the methods and processes utilise an object previously formed using an additive manufacturing process. In either group of examples, the stages of the methods and processes of the disdosure that do not include the formation of an object may be applied at any suitable time after the previous formation of the object. In one example, such stages of the methods and processes of the disdosure may be used immediately after, or substantially immediately after, the object has been formed. In another example, the stages of the methods and processes of the disdosure may be used some time after the object has been formed. In such examples, the methods and processes of the disdosure may be used, for example, up to and including about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, or about 24 seconds, minutes, hours, days, or weeks after the formation of the object.

[0013] The methods and processes of the disdosure include the formation and/or use of a canposition and/or mixture. The composition and/or mixture may indude a solvent and a polyamide. In one example, the composition and/or mixture may include a solution. In another example, the composition and/or mixture may include a slurry. In particular examples, the composition and/or mixture may be a solution or slurry. In the interests of conciseness the term ‘composition' will be used in the description that follows and is intended to refer to any composition, mixture, dispersion, or other combination of substances as described herein in relation to such compositions, mixtures, or the like. The composition may be formed by mixing a solvent and a polyamide. In one example, the solvent and the polyamide may be mixed using a mixer, stirrer, agitator, a* any other suitable method of combining or bringing together the solvent and the polyamide. The formation of the canposition may indude heating the solvent and/or the polyamide. In one example, the composition may be a saturated solution. In another example, the composition may be an unsaturated solution. Sone examples of the methods and processes of the disclosure do not indude the formation of a composition as described herein. In such examples, the competition may be obtained or provided without formation by the user and then used and/or applied to the methods and processes disdosed herein.

[0014] The solvent may be any solvent in which the polyamide may be partially a wholly dissolved. The solvent may include a polar solvent. The solvent may include an alcohol. In an example, the solvent may indude a fluorinated alcohol. The solvent may indude an add. Examples of suitable solvents indude, but are not limited to, benzyl alcohol, sulphuric add, m-cresol, formic add, trifluoroacetic add, tetrahydrofuran, dichloromethane, trifluoroacetic anhydride, hexafluoro-2-propanol, any other suitable solvent, or any combination thereof. In one example, the solvent may be a single solvent spedes. In another example, the solvent may be a combination of solvents or a solvent system including several solvent spedes. The polyamide may be any suitable polymer that contains recurring amide groups with the structure (R— CO— NH— R') within the polymer chain. In some examples, the polyamide may indude polyamide 12 (PA-12), polyamide 11 (PA-11), polyamide 6 (PA-6), polyamide 8 (PA-8), polyamide 9 (PA-9), polyamide 66 (PA-6,6), polyamide 612 (PA-6,12), polyamide 812 (PA-8,12), and polyamide 912 (PA-9,12), any other suitable PA type or grade, or any combination thereof. In an example, the polyamide may indude PA- 12. In another example, the polyamide may include PA-11. In a further example the polyamide may include PA-6. In a yet further example, the polyamide may indude PA- 6/6. In one example, the polyamide may include a single polyamide species. In another example, the polyamide may indude multiple polyamide species. The composition may include any suitable proportions of solvent and polyamide. In some examples, the polyamide may be present in the composition in an amount of from about 1% to about 60% by weight of total composition, that is up to and induding about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, or any other suitable amount, by weight of total composition. In other examples, the weight ratio of solvent to polyamide present in the composition may range from about 99:1 to about 40:60. In other examples, the polyamide may be present in an amount of greater than about 60% by weight of the composition where the polyamide may be dissolved and/or slurried in the presence of a particular solvent in such an amount. The composition may indude additional components or materials. In one example, the composition may indude a pigment to impart colour to the portion or portions of the object to which the composition is to be applied.

[0015] The composition may be applied to at least part of an object. In one example, the compostion may be applied to an object such that the composition coats and/or is in contact with less than 100% of the surface area of the object In another example, the composition may be applied to the object such that the composition coats and/or is in contact with the entirety of the surface area of the object. In other examples, the composition may be applied to specific portions of the object where strengthening or reinforcement may be beneficial. Such portions of the object may include, but are not limited to, joints, bends, comers, areas with abutting surfaces, surfaces in a plane other than the direction of printing, any other suitable portion, or any combination thereof. The composition may be applied to the object via any suitable process. For example, the composition may be applied to the object by a process including, but not limited to, brushing, spraying, spray drying, rolling, dropping, dripping, dipping, injecting, transferring, submersion, immersion, aerosdisation, spreading, padding, any other suitable technique, or any combination thereof. In one example, a single technique is used to apply the composition to the object. In another example, multiple techniques may be used. In one example, a brushing technique may be used to apply the composition to a portion of the object with a dropping technique used to apply the composition to a different portion of the object. Some techniques such as brushing, spraying, and submersion may be suitable for applying the composition to a larger surface area of the object whereas other techniques such as dropping, dripping, and injecting may be suitable for applying the composition to portions of an object with a smaller surface area. In some examples, a single composition may be applied to the object. In other examples, multiple compositions may be applied to an object. In examples where multiple compositions are applied to an object, the compositions may indude different proportions of the same materials and/or include different components from one composition to the other. Moreover, in examples where multiple compositions are applied to an object, each composition may be applied to the same and/or different portions of the object. In one example, a first composition may be applied to a first portion of an object and a second composition may be applied to a second portion of an object where the first composition and second composition are different and the first portion and the second portion are different Although this example indudes two compositions, further additional compositions and portions of the object may be included.

[0016] The methods and processes of the disclosure indude heating. The object and composition may be heated following application of the composition to the object. The heating may be performed using any suitable process or apparatus. For example, the heating may be carried out using an oven, heater, infrared source, hot gas system, any other suitable heating system, or any combination thereof. In one example, the heating may be performed by applying energy, or thermal energy, to the object. The heating may include increasing the temperature of the object and/or composition to a temperature below the melting point of the polyamide of the composition and/or the material used to form the object. Heating the object and/or the composition to a temperature below the melting point of the materials involved may reduce the risk of distortion or dimensional compromise of the part which may be induced by higher temperatures. The heating may indude increasing the temperature of the objed and/or composition to a temperature at which the solvent included in the composition will evaporate. In some examples, the temperature may be increased to a temperature above the boiling point of a solvent included in the composition. In some examples, the heating may increase the temperature of the object to a temperature of from about 40 °C to about 160 °C. For example, the heating may increase the temperature of the object and/or composition up to and induding about 40 °C, about 45 °C, about 50 °C, about 55 °C about 60 °C, about 65 °C about 70 °C, about 75 °C, about 80 °C, about 85 °C, about 90 °C. about 95 °C, about 100 °C, about 105 °C, about 110 °C. about 115 °C about 120°C, about 125 °C, about 130 °C, about 135 °C. about 140 °C. about 145 °C. about 150 °C, about 155 °C, or about 160 °C. Greater temperatures may be used where the characteristics of materials allow. The skilled person, in view of this disdosure, will be able to establish the melting point of the materials used in the object and composition to determine a suitable temperature for the heating.

[0017] The heating process may cause the evaporation or loss of the solvent from the composition and the formation of a solid mass of material where the composition had been applied to the object. In some examples, the heating process may therefore be considered to be a solvent welding process. The solid mass of material formed on the object may be a semi-crystalline layer or shell on the surface of the object. The solid mass of material may include the polyamide of the composition. An object heated by the methods and processes of the disclosure may include an elastomer core with a semi-crystalline outer shell. In one example, the portions of the object to which the composition is applied may, following heating, have distinct cross sectional layers differentiating the core of the object and the layer or shell thus formed using the composition. In other examples, the composition may penetrate, ingress, or otherwise enter the outer surface of the object to form a solid mass with regions of mixing or interaction with the core of the object. The degree of distinction and/or separation of the core of the object and the layer and/or shell formed from the composition may depend upon factors such as the topography of the object and the components of the composition at the time of application to the object. For example, an object with a porous topography may allow for a greater extent of ingress of the composition into the structure of the object than an object with a non-porous or substantially smooth topography. In another example, a solvent that is capable of at least partially dissolving the material used to form the object may result in cross-sectional regions following heating where the solid polyamide formed from the heating of the composition is mixed or interspersed with the material of the object. In another example, heating the object and/or composition to a temperature close to, at. or beyond the melting point of the polyamide or the material used to form the object may result in a greater degree of ingress of the polyamide into the surface of the object following heating when compared to a heating process at a lower temperature. Without being bound by theory, it is believed that the use of a composition including a solvent and a polyamide may allow for the breakdown of the polyamide bonds at lower temperatures which, in turn, allows an object to be coated or otherwise and treated at lower temperatures than may be used to apply such a polyamide directly to an object using an additive manufacturing system.

[0018] The methods and processes of the present disclosure may increase the strength of a three-dimensional printed object. The increase in strength may be an increase in tensile strength, strain tolerance, crush resistance, or any other suitable increase in strength that may be provided at least in part by the polyamide used in the composition. In one example, an object treated according to the methods and processes of the disclosure may have increased tensile strength. In another example, an object treated according to the methods and processes of the disclosure may exhibit a greater percentage strain at the point of break or failure. In some examples, an object treated according to the methods and processes of the present disclosure may show substantially no change in Young's modulus. In other examples, the Young's modulus of an object may decrease following the methods and processes of the disclosure. The methods and processes may form a strong polyamide shell with different characteristics to those of the object upon which the shell is formed. The properties and/or material used to form the original object and the properties and/or materials of the polyamide shell may work synergistically together to provide a coated object with different characteristics to those of the original object or polyamide shell when considered in isolation. The methods and processes of the disclosure may therefore be used to form parts for use in applications where strength and resilience are helpfol. Examples of such parts include structural components, footwear midsoles, automotive components, prosthetics, and other parts that may be subjected to forces, shocks, pressure, or the like during use. The extent of the increase in the strength and/or resilience of an object may depend upon the structure of the object and/or the manner in which the object was manufactured. A greater increase may be observed where an object has a porous surface topography whereas a lesser increase may be observed where an object has a smooth surface topography. When the composition is applied to portions of an object where build layers meet or join, the increase in strength or resilience may be greater than if the composition were applied to a portion of the object where the surface is formed by a single layer.

[0019] Materials that may be unsuitable for some additive manufacturing processes may be applied to an object using the methods and processes of the present disclosure. In an example, a 3D printing apparatus may be unable to use particular polyamide materials such as PA-6 and/or PA-6,6 materials to directly manufacture an object. The use of the methods and processes disclosed herein may allow any class of polyamide material such as PA-12, PA-11, PA-6, PA-8, PA-9, PA-6,6, PA-6,12, PA- 8,12, PA-9,12, any other suitable PA type or grade, or any combination thereof to be applied to an object that would otherwise not include such material following an additive manufacturing process alone. In this manner, objects formed using additive manufacturing processes can include materials that may be used to form the compositions described herein where such materials could not otherwise be used to form such an object. [0020] The methods and processes of the present disclosure and the individual stages thereof may be canted out across any suitable period of time. Formation or manufacturing of a three-dimensional object, application of a composition to the object, and/or heating of the object may each be carried out or collectively carried out, for example, across a time period up to and including about 1 , about 2, about 3, about 4, about 5. about 6, about 7, about 8, about 9, about 10, about 11, about 12. about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24 minutes, hours or days. The time period across which any individual stage of the methods and processes, and/or the entirety of the method or process, should be carried out will depend at least in part upon the nature of an object, the geometry of an object, the topography of an object, the materials used in the formation of an object or composition, and/or the intended end-use of the object to which a composition is to be applied. In one example, an object may be formed via an additive manufacturing process across a period of several hours. The object may then be stored for a period of over 24 hours before the application of a composition to the object across a period of about 10 minutes. the object with the applied composition may then be transferred immediately to an oven where it is heated for a period of about 3 hours before being allowed to cool. In one example, an object with a greater surface area to volume ratio may be heated for less time than an object with a lesser surface area to volume ratio. In one example, the time period between the application of the composition to the object and the heating of the object may be minimised to limit and/or prevent the migration of the composition across the object away from the portion or portions of the object to which the composition was originally applied.

[0021] Additional operations may be included at any suitable stage of the methods and processes of the present disclosure. In one example, the object, once formed, may be cleaned, washed, sanded, blasted, polished, abraded, exposed to any other suitable process, or any combination thereof. For the avoidance of doubt, 'blasting' may involve projecting air or other gases towards at least part of an object. The air or other gases may include a particulate or a mixture of particulates such as sand or other abrasive particles. In one particular example, a blasting process may be a sand-blasting process. The additional operations described herein may be performed on an object following additive manufacturing and/or following application of a composition to the object and subsequent heating. In another example, an object may undergo a thermal treatinent process distinct from the heating of the object and applied composition. In such an example, the object may undergo an annealing process to condition the material used to form the object. Where an object and composition have been heated to form an object with a polyamide shell, the object and polyamide shell may undergo an annealing process to further condition the object and/or polyamide shell.

[0022] In one example of the methods and processes disclosed herein, an object may be manufactured from a thermoplastic polyamide elastomer build material using additive manufacturing layering material in the z-orientation. The object thus formed may be coated in a thin layer of a composition including benzyl alcohol solvent and PA-12 polyamide. The coated object may then be placed in an oven operating at a temperature of about 50 °C to about 155 °C to form a PA-12 shell on the object. In other examples where different materials may be used the temperature of the oven may be different and will depend upon the thermal characteristics of each material. The chemical structure of benzyl alcohol and PA-12 are shown below in structure (1) and structure (2), respectively. Further examples of the methods and processes will now be described with reference to the figures.

[0023] Figure 1 shows an example of a method 100. The method 100 includes providing 101 a composition comprising a solvent and a polyamide. The method 100 further includes applying 102 the composition to at least part of an object formed from an additive manufacturing process. The method 100 also includes heating 103 the object.

(0024] Figure 2 shows an example of a process 200. The process 200 includes manufacturing 201 an article from a first polymer material using three-dimensional printing. The process 200 includes coating 202 at least a portion of the artide with a mixture comprising a solvent and a second polymer material comprising a polyamide to form a coated artide. The process 200 further includes applying 203 energy to the coated article.

[0025] The method and process of Figure 1 and Figure 2 may include any number of the following features in any combination. The solvent may include an alcohol. The alcohol may include benzyl alcohol. The polyamide may include PA-6, PA-6,6, PA-11, PA-12, or any combination thereof. The composition or mixture may include a solution and/or a slurry. Heating the object and/or applying energy to the coated article may indude increasing the temperature of the object to a temperature below the melting point of the polyamide and below the melting point of the material forming the object and/or article. Heating the object and/or applying energy to the coated artide may indude increasing the temperature of the objed and/or coated article to a temperature of from about 50 °C to about 155 °C. The heating may increase the temperature of the object to a temperature of from about 40 °C to about 160 °C. The heating may increase the temperature of the object and/or composition up to and induding about 40 °C, about 45 °C. about 50 °C, about 55 °C about 60 °C, about 65 °C about 70 °C, about 75 °C, about 80 °C, about 85 °C, about 90 °C, about 95 °C, about 100 °C, about 105 °C. about 110 °C. about 115 °C about 120 °C, about 125 °C, about 130 °C, about 135 °C, about 140 °C, about 145 °C, about 150 °C, about 155 °C, or about 160 °C. Manufacturing the artide and/or object may indude using three-dimensional printing in the z-orientation to produce the article and/or object. Applying the composition to the object, and/or coating at least a portion of the article with the mixture may indude brushing, spraying, spray drying, rolling, dropping, dripping, injecting, transferring, submersion, immersion, aerosolisatlon, spreading, padding, or any combination of processes to contact the composition and/or mixture with the object and/or artide. The method or process may include cleaning, washing, sanding, abrading, blasting, polishing, and/or annealing the object and/or artide.

[0026] The methods and processes of the present disclosure may be carried our wholly or in part by a computer, computing device, computer system, automated processing system, or the like. In one example, Figure 3 shows a non-transient computer readable medium comprising instructions which, when executed on a computing device 301, cause the computing device to: administer 310 a solution or slurry comprising a solvent and a polyamide to a printed part of a three-dimensional printed job; and heat 320 the printed part and the solution or slurry. The computing device 301 may comprise a processor. The computing device 301 may be communicably coupled to an additive manufacturing system, a post-processing unit, a cleaning unit, a build unit, a heating unit, or any combination thereof. The non- transient computer readable medium may be any electronic, magnetic, optical or other physical storage device that stores executable instructions, sometimes referred to as a memory 302. Thus, the non-transient computer readable medium may be, for example. Random Access Memory (RAM), and Electrically-Erasable Programmable Read-Only Memory (EEPROM), a storage drive, an optical disc, or the like. A computing device such as computing device 301 may allow the methods and processes of the disclosure to be carried out with minimal or no interaction from a user. In one example, a user may input a start command into the computing device using a switch, user interface, or other input means to start the process of the method. Once the start command has been issued, the computing device may carry out the instructions stored on the non-transient computer readable medium to apply a composition to an object and then heat the object.

[0027] Figures 4 to 6 show some practical examples of the changes in properties and characteristics of material that may be achieved when the methods and processes of the present disclosure are applied. Figure 4 shows analytical data for three samples tested for the percentage strain induced prior to breakage of the sample. A control sample was produced from thermoplastic polyamide via additive manufacturing and was subjected to no further treatment. A second sample was prepared in the same manner as the control sample and was heated to about 153 °C for one hour with no further treatment. A third sample was prepared in the same manner as the second sample but a coating of benzyl alcohol and PA-12 solution was applied to the sample prior to heating. The data presented in Figure 4 shows the increase in percentage strain obtained by both heating a sample alone and by coating and heating the sample. The increase in percentage strain at break achieved in the coated and heated sample is greater than observed for the control sample and the sample that was heated without further treatment. [0028] Figure 5 shows charts demonstrating the Young’s modulus and tensile strength of the three samples created and tested in the examples illustrated in Figure 4. The upper chart shown in Figure 5 demonstrates that the Young's modulus of a coated and uncoated sample following heating is substantially similar. A coating of PA-12 and benzyl alcohol may have little to no effect on the Young’s modulus of an object following heating. Ute lower chart of Figure 5 shows that the tensile strength of the heated sample was greater than that of the control sample without heating. It is notable that the sample that was coated and heated using the methods and processes of this disclosure showed the greatest tensile strength of the three samples tested.

[0029] Figure 6 shows another chart demonstrating the percentage strain at break for four samples. As described in relation to Figures 4 and 5, four samples were prepared by using additive manufacturing to form objects from thermoplastic polyamide in the z-orientation. One sample was retained as a control without further treatment or processing. A second sample was heated for one hour in an oven at about 150 °C without further treatment or processing. A third sample was coated in benzyl alcohol and heated in an oven for one hour at about 150 °C. A fourth sample was coated in a mixture of benzyl alcohol and PA-12 and heated in an over at about 150 °C for an hour. The percentage strain at break of the control sample was lower than that of the other three samples. The samples that did not include a PA-12 coating showed an increase in percentage strain when compared to the control sample. However, the sample that had been coated with the benzyl alcohol and PA-12 showed the greatest increase in percentage strain at break when compared to the control sample. These experiments demonstrate the influence of the combination of a solvent and a polyamide in the coating composition as the maximum increase in strength is not achieved when the solvent is applied without a polyamide.

[0030] Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.

Claims

1. A method comprising: providing a composition comprising a solvent and a polyamide; applying the composition to at least part of an object formed from an additive manufacturing process; and heating the object.

2. The method of claim 1, wherein the solvent comprises an alcohol.

3. The method of claim 2, wherein the solvent comprises benzyl alcohol.

4. The method of daim 1, wherein the polyamide canprises polyamide 12, polyamide 11 , polyamide 6, polyamide 8, polyamide 9, polyamide 66, polyamide 612, polyamide 812, polyamide 912, or any combination thereof.

5. The method of claim 1, wherein: the object comprises thermoplastic polyamide; the solvent comprises benzyl alafool; and the polyamide canprises polyamide 12.

6. The method of claim 1 , wherein the composition comprises a solution and/or a slurry.

7. The method of daim 1, wherein heating the object comprises increasing the temperature of the object to a temperature below the melting point of the polyamide and below the melting point of the material forming the object.

8. A process canprising: manufacturing an article from a first polymer material using three-dimensional printing; coating at least a portion of the article with a mixture comprising a solvent and a second polymer material to form a coated article, wherein the second polymer comprises a polyamide; and applying energy to the coated article.

9. The process of claim 8, wherein the second polymer comprises PA-8, PA-9, PA-6,12, PA-8,12, PA-9,12, PA-6, PA-6,6, PA-11, PA-12, or any combination thereof.

10. The process of claim 8, wherein manufacturing the article comprises using three-dimensional printing in the z-orientation to produce the article.

11. The process of claim 8, wherein coating at least a portion of the article comprises applying the mixture to at least a portion of the article by brushing, spraying, spray drying, rolling, dropping, dripping, dipping, injecting, transferring, submersion, immersion, aerosolisation, spreading, padding, or any combination thereof.

12. The process of claim 8, further comprising cleaning the article and/or coated article, washing the article and/or coated article, sanding the article and/or coated article, abrading the article and/or coated article, blasting the article and/or coated article, polishing the article and/or coated article, or any combination thereof.

13. The process of claim 8, wherein applying energy to the coated article comprises increasing the temperature of the coated article to a temperature of from 50°C to 155°C

14. A non-transitory computer-readable medium comprising instructions, which when executed on a computing device, cause the computing device to: administer a solution or slurry comprising a solvent and a polyamide to a printed part of a three-dimensional printed job; and heat the printed part and the solution or slurry.

15.The non-transitory computer-readable medium of claim 14, further comprising instructions, which when executed on the computing device, cause the computing device to: form tiie printed part of the three-dimensional print job using a three- dimensional printing process.