Apparatus and method

Abstract

A method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation and a second ink formulation, thereby influencing a first microstructure of the first layer.

Description

[0001] APPARATUS AND METHOD

[0002] Field

[0003] The present invention relates to a method of ink jetting and an article manufactured using ink jetting.

[0004] Background to the invention

[0005] Advanced manufacture, specifically additive manufacture, can increase industrial productivity and competitiveness by reducing the time required to bring new products to the marketplace and by providing for flexible manufacture of products that cannot economically and robustly be produced by other means, and by providing a range and control of the materials used within the parts.

[0006] It is well understood that the material properties contribute to the part’s overall performance. The present invention is focused on the material’s microstructure which is the foundation of the material’s properties. Such properties include, but are not limited to, conductivity in thermal and electrical sense, mechanical strength and compliance, visual appearance including surface finish.

[0007] Currently there is a limited set of materials available for use in additive manufacturing and most are based on those used in other more commonly used manufacturing methods. The variability and control of material microstructure enables a greater range of materials than are possible for use in those more commonly used manufacturing methods.

[0008] When a new material is produced, it is often the case that its properties are determined after it has been used in a part rather than during formulation. Optimisation is a lengthy process as the formulation is altered in small steps which are often associated with just one parameter. A new part is manufactured and then tested. This process is iterated many times before an optimal formulation and manufacturing process control / method has been determined.

[0009] Additive manufacturing, commonly referred to as 3D printing, is a term which encompasses several categories of processes by which 3D objects are formed or “printed”. The 3D objects are generally built up layer by layer, and the processes differ in the way that the layers are formed and in what they are made from.

[0010] Some processes entail polymerising or curing liquid material. For example, in vat photopolymerisation, a platform is lowered into a vat of liquid polymerisable material (e.g. epoxy acrylate resin) so that it is slightly below the surface. Laser radiation is used to polymerise and harden selective parts of the layer above the platform. The platform is then lowered slightly so that a new liquid layer is at the surface (this may be made uniform by using a levelling or coating blade) and the polymerisation process is repeated. This procedure of lowering, coating and polymerising is repeated layer by layer until the desired three-dimensional structure has been formed. The platform may then be raised and the product removed and processed further. Postprocessing typically involves the removal of support structures (which may be formed during the polymerisation steps) and any other residual material, and then high temperature curing following by finishing, e.g. sanding of the product.

[0011] Some other processes entail forming each layer of a 3D structure by extruding a plastic or polymer material (or, less commonly, other material). This is known as extrusion deposition or fused deposition modelling (FDM). Material, e.g. a polylactic acid resin, is fed to an extruder where it is heated and extruded through a nozzle which moves in X and Y directions. The selectively deposited material solidifies on cooling. As with vat polymerisation methods, the structure usually rests on a build platform which typically moves downwards between the deposition of each layer, and support structures are typically required, particularly for overhanging parts of structures. Such extrusion methods are amongst the most common 3D printing processes and used widely in consumer 3D printers.

[0012] Another category of additive manufacturing is material jetting which is similar to extrusion deposition in that material is deposited via a nozzle which moves in X and Y directions. Instead of being extruded, the material is jetted onto a platform. The material (e.g. wax or polymer) is applied as droplets using a print head, similar to conventional two-dimensional inkjet printing. The droplets solidify and then successive layers are applied. Once the structure is formed it may be subjected to curing and post-processing. As with other methods discussed above, support structures may be incorporated during the procedure and then removed during post processing. Powder bed fusion (PBF) methods entail the selective binding of granular materials. This can be done by melting and fusing together part of the powder or particles of a layer of material, then lowering the bed, adding a further layer of powder and repeating the melting and fusing process. The unfused powder around the fused material provides support so unlike some methods discussed above it may not be necessary to use support structures. Such methods include direct metal laser sintering (DMLS), electron beam melting (EBM), selective heat sintering (SHS), selective laser melting (SLM) and selective laser sintering (SLS). In view of the types of materials which are compatible with such processes (including metals and polymers), functional high strength materials can be manufactured.

[0013] Binder jetting (also known as ink jetting) methods are similar to powder bed fusion methods in that they use layers of powder or particulate material. However, conventional binder jetting methods differ from powder bed fusion methods in that the powder is not initially fused together but instead is held together with a binder which is jetted onto the structure from a print head. The binder may be coloured, and the colour may be imparted to the powder thereby allowing colour 3D printing. Typically, a binder is applied in a specific pattern to a layer of powder, and then the steps of applying a layer of powder and selectively applying binder are repeated.

[0014] In general, binder jetting entails the use of binder as a sacrificial material which is altered or removed in a post-processing step. This is because the adhesive binder typically imparts enough mechanical strength (termed “green strength”) to enable the structure to be self-supporting and maintain its shape as it is built up, and to withstand mechanical operations during manufacture, but not enough strength to be functional for the intended end use. Thus, the structure is usually subsequently heated to remove the binder (de-binding process) and to fuse the build material together in a post-processing step to ensure that the product is fit for purpose which may include load-bearing or other applications.

[0015] Binder jetting is also referred to as “ink jetting”, the “drop-on” technique, “powder bed and inkjet 3D printing”, or sometimes just “3D printing”, though as summarised here there are many other different types of 3D printing. The binder used in binder jetting is generally liquid and is often referred to as “ink” in view of the inkjet application process.

[0016] Summary of the Invention

[0017] A first aspect provides a method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation; and controlling binding of the first layer of the first powder by the first ink formulation comprising regulating forming of first particles from the first ink formulation in the first layer of the first powder, thereby influencing a first microstructure of the first layer.

[0018] A second aspect provides a computer comprising a processor and a memory configured to implement, at least in part, a method according to the first aspect, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the first aspect or a non-transient computer-readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the first aspect.

[0019] A third aspect provides an article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation.

[0020] A fourth aspect provides a method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation and a second ink formulation, thereby influencing a first microstructure of the first layer.

[0021] A fifth aspect provides a computer comprising a processor and a memory configured to implement, at least in part, a method according to the fourth aspect, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the fourth aspect or a non-transient computer-readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the fourth aspect.

[0022] A sixth aspect provides an article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation and a second ink formulation.

[0023] A seventh aspect provides a method of ink jetting according to the first aspect and the fourth aspect.

[0024] An eighth aspect provides an article according the second aspect and the fifth aspect.

[0025] A ninth aspect provides a method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation, thereby influencing a first microstructure of the first layer; providing a second layer of the first powder comprising the first material; jetting the second layer of the first powder with a second ink formulation, thereby influencing a first microstructure of the first layer; comprising mixing the first ink formulation and the second ink formulation, for example after jetting the second layer of the first powder with the second ink formulation, for example during permeation therethrough to the first layer. A tenth aspect provides an apparatus configured to implement the method according to the first aspect, the fourth aspect, the seventh aspect and / or the ninth aspect and / or to provide an article according to the third aspect and / or the eighth aspect.

[0026] Definitions

[0027] Functional material: A material specifically selected for its functional properties. E.g. resistivity of a certain value enables a specific cross-sectional-area to be used.

[0028] Non-sacrificial binder: Refers to a component of the ink and / or binder which provides some function to the green or brown part but is intended to remain in the final part. It may provide additional useful materials properties.

[0029] Organometallic: Compound I molecule containing at least 1 metal - carbon bond.

[0030] Powder bed: A bed of powder comprising a plurality of particles made up of the desired final part material. Particles are joined together via printed binder to produce the 3D green or brown part.

[0031] Hybrid manufacturing: Utilising both additive and subtractive manufacturing methods

[0032] Debinding: A heat treatment or part of the sinter cycle where the binder is removed from the green part - ideally as sintering begins.

[0033] Green part: The part (also known as article) as printed. Usually comprised of weakly held together particles with significantly lower strength than the bulk material.

[0034] Brown part: Heating the green body part above a first temperature to remove the binder and generate a brown body part; and when the binder has been crosslinked (or reacted) increasing the part strength compared to the green part. May also refer to where a reactive binder ink has undergone its reaction.

[0035] Release layer: A specifically printed area at a part edge where printing parameters are altered to reduce the strength in that area. Parameters may include ink composition, drop size, ink saturation

[0036] Ink: The complete liquid formulation that is jetted from the inkjet heads. May include, but not be limited to, carrier, binder, reactive components, particles, gels, viscosity modifiers, surface tension modifiers, anti-flocculation agents, pH modifiers, etc. Binder: The component of the ink that causes bed particles to become joined together during the printing process. This can be achieved by deposition of the target print material (i.e. the same material as the powder bed) in to the powder bed or by the addition of a different material, such as a polymer, which temporarily joins particles together until sintering.

[0037] Precursor: A chemical component of the ink that has been selected based on its reaction products. E.g. a metal salt or an organometallic compound used to deposit the metal atom after undergoing its reaction.

[0038] Particles: Solid material within the ink used to fill volume in the powder bed, provide reaction surfaces for the binders and or precursors, and to increase the final sintered volume of the part. Particles may be comprised of the bulk target material or an alternative material if specific functionalisation is required (e.g. oxide particles printed onto a metal powderbed to form an ODS alloy).

[0039] Solvent: Any substance capable of dissolving another substance and forming a solution.

[0040] Carrier or carrier vehicle: Fluid used as the bulk component in the ink (by volume) - generally chosen for its properties as a solvent its evaporation properties when printed.

[0041] Catalyst: A substance used to change the activation energy of a reaction, whilst not being consumed during the reaction.

[0042] Non-binding component: Any component of the ink which does not take part in joining the bed powder particles together after printing.

[0043] Heat treatment stage: A single part of a heat treatment cycle - example cycle broken into 7 stages: 1) loading and atmosphere preparation. 2) ramp up to 1st hold temperature. 3) Hold at 1st temperature for set time. 4) ramp up to 2nd hold temperature. 5) hold at 2nd temperature for set time. 6) cool to unloading temperature. 7) unload.

[0044] Jetting: The controlled ejection of ink from a nozzle in an inkjet head.

[0045] Multiple nozzles: Concerning an inkjet head containing more than one nozzle for ejection of ink.

[0046] Detailed Description of the Invention According to the present invention there is provided a method of ink jetting, as set forth in the appended claims. Also provided is an article manufactured at least in part by ink jetting. Other features of the invention will be apparent from the dependent claims, and the description that follows.

[0047] The present invention is a method for controlling 3D microstructure through control of ink formulation and / or powder bed constituents. The ink formulation and control / method may be determined prior to the manufacture and test of the first article.

[0048] The invention is based on ink jetting, although the materials and control / method may be applicable to other current or future manufacturing techniques.

[0049] The present invention relates to additive manufacturing, also known as 3D printing, and in particular to ink jetting, components used in ink jetting, and resultant products, although the materials and control / method may be applicable to other current or future manufacturing techniques.

[0050] This invention relates generally to the advanced manufacture of tooling and prototype parts and production parts and, more particularly, to the use of three-dimensional printing techniques using computer models, therefore.

[0051] Method of ink jetting

[0052] The first aspect provides a method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation; and controlling binding of the first layer of the first powder by the first ink formulation comprising regulating forming of first particles from the first ink formulation in the first layer of the first powder, thereby influencing a first microstructure of the first layer.

[0053] In this way, the first microstructure of the first layer is influenced, for example determined such as in combination with properties of the first powder, the first material, the first ink formulation and / or optionally post-processing such as heat treatment, since the formation of the first particles from the first ink formulation is regulated (i.e. controlled). In this way, the microstructure of individual layers may be controlled interlayer. In this way, the microstructure of specific voxels may be controlled intralayer and / or interlayer.

[0054] The method according to the first aspect may include any step described with respect to the fourth aspect. In one example, controlling binding of the first layer of the first powder by the first ink formulation comprising regulating forming of the first particles from the first ink formulation in the first layer of the first powder, thereby influencing a first microstructure of the first layer, comprises controlling binding of the first layer of the first powder by the first ink formulation comprising regulating forming of the first particles from the first ink formulation in the first layer of the first powder, thereby influencing a first microstructure and a first property of the first layer, for example a mechanical property, a thermal property, an electrical property, etc.

[0055] In one example, the first ink formulation comprises a solvent, a catalyst, a precursor material, a carrier vehicle, a growth agent and / or an inhibitor, as described below in more detail.

[0056] In one example, the first particles comprise nanoparticles, for example formed on surfaces of the first powder and / or within the first ink formulation, for example by reaction such as initiated by a catalyst and / or post processing such as heat treatment.

[0057] In one example, regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises regulating forming of the first particles from the first ink formulation and the first powder in the first layer of the first powder and / or regulating forming of the first particles from the first ink formulation on the first powder in the first layer. In this way, the first particles are formed from the first ink formulation and optionally from the first powder, for example by reaction such as initiated by a catalyst and / or post processing such as heat treatment.

[0058] In one example, regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises modulating dosing of the first ink formulation, for example selectively such as according to a pattern and / or for selected voxels. In this way, the dosing (i.e. dosage rate) of the first ink formulation is modulated (i.e. controlled) such that relatively lesser or greater amounts of the first ink formulation are jetted, for example selectively. In this way, the first microstructure may be influenced selectively within the first layer. Printing of the inks allows precise control of the quantity of ink delivered per voxel via greyscale levels, multiple print passes, print waveform, piezo-voltage (all potentially controllable on the fly), and ink composition (viscosity, surface tension) which determines drop size, satellite formation, etc..

[0059] In one example, the method comprises selecting a particle size distribution of the first powder.

[0060] In this way, a density of the first layer may be controlled, thereby influencing the first microstructure. Generally, powder bed particle size distribution determines packing density of powder particles. To increase density, multimodal size distributions may be used. To decrease density, monomodal distributions with a tight distribution widths may be used. Powder PSD optionally bimodal (two sizes): o Could also be used to create alloy or composite materials by choosing different materials in each mode.

[0061] Bimodal optionally with two different materials: o Powder 1 , range 0 - 100% o Powder 2, range 100 - 0 % o Can achieve different bed powder densities by varying ratio of powders.

[0062] In one example, the method comprises selecting a particle morphology of the first powder. In this way, a density of the first layer may be controlled, thereby influencing the first microstructure. Generally, spherical or near spherical particles may be used to give good flowability and spreading characteristics.

[0063] In one example, providing the first layer of the first powder comprises providing the first layer of the first powder having the selected particle size distribution and / or particle morphology.

[0064] In one example, providing the first layer of the first powder comprising the first material comprises providing the first layer of the first powder comprising the first material and of a second powder comprising a second material. For example, the first powder and the second powder may have different particle size distributions. For example, the first powder and the second powder may have different particle morphologies. For example, the first material and the second material may be different.

[0065] In one example, regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises exposing the first layer of the first powder and / or the first ink formulation to a first atmosphere. In this way, by regulating forming of the first particles, the final microstructure and thus the materials properties may be controlled. For air sensitive and / or moisture sensitive inks, the atmosphere may consist of Ar or N gas at some value above atmospheric pressure. O2 and H2O levels may be monitored within the print environment. For some materials, the atmosphere may be cycled to include quantities of gaseous reactants (e.g. H2O, O2, H2, O3, etc) to react with the printed ink to form ceramic materials.

[0066] 0 The build piston, build area, print area and / or ink system may all be enclosed and isolated from the outside atmosphere during setup, build and heat treatment. A ventilation system may be linked to the enclosure to vent gases in the case of over pressure.

[0067] In one example, regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises heating (more generally, post processing) the first layer of the first powder and / or the first ink formulation, for example before, during and / after jetting the first layer of the first powderwith the first ink formulation. In this way, the first layer is heat-treated (more generally, post-processed). o Example - YSZ inks: oxidation of YSZ ink and degassing of carrier I byproducts can be wholly carried out in the print bed. During printing a moderately elevated bed temperature is used (around 50 °C) to boil off the butanol carrier. H2O vapour is introduced periodically to react Y and Zr butoxides forming more butanol which is boiled off.

[0068] 0 2nd example - Al ink. First part of the heat treatment (DMEAA decomposition and degassing of toluene) is carried out in the printbed at temperatures of between 50 °C and 100 °C.

[0069] 0 In future printers, it may be possible to transfer the build to another area of the printer, whilst still maintaining the integrity of the enclosure for a high temperature heat treatment (l.e sintering, forming gas anneal, etc).

[0070] In one example, jetting the first layer of the first powder with the first ink formulation comprises jetting the first layer of the first powderwith the first ink formulation and a second ink formulation; and regulating forming of first particles from the first ink formulation in the first layer of the first powder comprises regulating forming of first particles from the first ink formulation and the second ink formulation in the first layer of the first powder. In this way, the first layer is independently jetted with the first ink formulation and the second ink formulation, thereby allowing independent control thereof.

[0071] 0 For a two part ink, e.g. Y butoxide I Zr butoxide, each part could be jetted separately to achieve control of the final oxide composition and microstructure.

[0072] 0 Another example could be Ti dioxide ink. One ink contains the Ti precursor and the other contains seed nanoparticles. Amorphous TiO2 would be printed (after oxidation by the controlled atmosphere) with the first ink, which could be graded into crystalline material with the introduction of the second ink containing seed crystals. By increasing the seed crystal dose over a few layer a graded amorphous to crystalline pattern could be produced.

[0073] In one example, regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises respectively regulating forming of the first particles from the first ink formulation in mutually adjacent voxels of the first layer of the first powder. In this way, the microstructure may be influenced at the voxel scale for mutually adjacent voxels i.e. intralayer.

[0074] In one example, jetting the first layer of the first powder with the first ink formulation comprises jetting the first layer of the first powderwith the first ink formulation and a second ink formulation; and regulating forming of first particles from the first ink formulation in the first layer of the first powder comprises respectively regulating forming of the first particles from the first ink formulation and the second ink formulation in mutually adjacent voxels of the first layer of the first powder. In this way, the microstructure may be influenced at the voxel scale for mutually adjacent voxels i.e. intralayer.

[0075] In one example, the method comprises providing a second layer of the first powder comprising the first material; jetting on to the second layer of the first powder with the first ink formulation; and controlling binding of the second layer of the first powder by the first ink formulation comprising regulating forming of the first particles from the first ink formulation in the second layer of the first powder, thereby influencing a second microstructure of the second layer; wherein the first microstructure and the second microstructure are mutually different.

[0076] In this way, the microstructure may be influenced at the layer scale for mutually adjacent layers i.e. interlayer.

[0077] In one example, the first ink formulation comprises one or more binder components. Examples of binder components include:

[0078] • Copper Ink - Ink formulation contains Cu formate tetrahydrate which reacts to leave Cu metal binder when taken above temperatures ~200 °C.

[0079] • One or two part Al ink - First ink contains diethylmethylamine alane (DMEAA). Unable to bind material on its own. Second ink contains Ti isopropoxide (IV) (TiPr), also incapable of binding particles on its own. If second ink is printed onto 1st ink and bed temperature is raised to >50 °C, the TiPr catalyses the decomposition of DMEAA into Al metal, dimethylethylamine and hydrogen. The Al metal deposits onto the powder bed, binding particle together.

[0080] • YSZ ink - Yttrium butoxide in butanol and Zirconium butoxide in butanol jetted separately or from a pre-mixed ink. Can produce flat films of YSZ with controlled Y content, or jetted onto YSZ powderbed and allowed to oxidise with atmospheric H2O to bind particles together.

[0081] In one example, the first ink formulation comprises one or more precursor build material. Examples of precursor build material include:

[0082] • Cu ink (see above)

[0083] • Al ink (see above)

[0084] • YSZ ink (see above)

[0085] • Binder component ratio controlled by mass or volume measurements during ink formulation

[0086] • For multiple binder systems (e.g. YSZ inks with precursors separated in separate inks) ratio of printed inks controlled by print strategy (i.e. dropsize, greyscale, no of passes, relative saturation). In one example, the first ink formulation comprises one or more growth agents or inhibitors. Examples of growth agents and inhibitors include:

[0087] • Organometallics are widely used for their catalytic properties to lower reaction activation energies - due to their organic nature, they are (relatively) easy to modify via grafting of functional groups, side chains, (see https: / / www.masterorganicchemistry.com / reaction- guide / #reactions-of-organometallics), etc. The “decoration” around the metal atom further modifies the interaction of the catalyst with the reactants.

[0088] • Example - the decomposition temperature of DMEAA is controlled in this ink by Ti isopropoxide, bringing the decomposition temperature to 50 °C from 76 °C for raw DMEAA. Tebbe’s reagent or trioctylamine could be used instead of TiPr to change the decomposition temperature to 65 °C and 250 °C respectively.

[0089] • Limits - see above. Quantity of catalyst determined during ink formulation by mass measurements.

[0090] In one example, the first ink formulation comprises one or more nano I microparticles. Examples of nano I microparticles include:

[0091] • Another example could be Ti dioxide ink. One ink contains the Ti precursor and the other contains seed nanoparticles. Amorphous TiO2 would be printed (after oxidation by the controlled atmosphere) with the first ink, which could be graded into crystalline material with the introduction of the second ink containing seed crystals. By increasing the seed crystal dose over a few layers, a graded amorphous to crystalline pattern could be produced.

[0092] In one example, the first ink formulation comprises one or more particles, solvents, catalysts, precursor material and / or carrier vehicle. Examples include: o Al ink composition: Toluene (solvent, carrier), Al nanoparticles (particles), Ti isopropoxide (catalyst), Dimethylethylamine alane (precursor material). o Limits - 0 to 100% for solvent and carrier, 0 to 50vol% for particles, 0 to 10wt% for TiPr, 0 to 100% for DMEAA in toluene (0.5M).

[0093] In one example, the first ink formulation comprises one or more catalysts. Example of catalysts include: o Organometallics are widely used for their catalytic properties to lower reaction activation energies - due to their organic nature, they are (relatively) easy to modify via grafting of functional groups, side chains, (see https: / / www.masterorganicchemistry.com / reaction- guide / #reactions-of-organometallics), etc. The “decoration” around the metal atom further modifies the interaction of the catalyst with the reactants. o Example - the decomposition temperature of DMEAA is controlled in this ink by Ti isopropoxide, bringing the decomposition temperature to 50 °C from 76 °C for raw DMEAA. Tebbe’s reagent or trioctylamine could be used instead of TiPr to change the decomposition temperature to 65 °C and 250 °C respectively. o Limits - see above. Quantity of catalyst determined during ink formulation by mass measurements.

[0094] In one example, the first ink formulation comprises one or more non-binding components, catalysts, particles, and / or carrier vehicle.

[0095] In one example, the method comprises controlling processing during printing and / or heat treatment stage. o During printing - Example for Al ink, O2 and H2O levels are reduced to ppm to prevent oxidation of Al and Ti. Initial reduction via purging chamber with Ar or N2 gas. May use pump on chamber to reduce pressure (pump-purge system). Could also use sacrificial chemical reduction method to remove final atmospheric species, e.g. small reservoir of TiPr or SnCk opens once O2 and H2O levels are sufficiently low, to getter remaining O2 and H2O. Opens periodically if O2 or H2O levels rise.

[0096] 0 During first part heat treatment (could be during print, after each layer, or after build), bed temperature is raised to 50-70C to decompose DMEAA and form Al nanoparticles. O2 and H2O levels need to be kept low.

[0097] 0 For YSZ ink, O2 and H2O levels need to be low during the print stage, but after each layer (or several layers or full build), H2O vapour could be introduced to oxidise the ink. This could also be done after the final print.

[0098] 0 O2 and H2O levels may be continuously monitored in the chamber and recirculation line to ensure correct operating parameters required by the ink.

[0099] In one example, the method comprises controlling temperature of the processing.

[0100] 0 Temperature of the print bed is controlled by cartridge heaters with feedback from thermocouples located around the build area. Temperature should be set for each process - e.g. Al printing, low bed temp during print (RT - 40C). after each layer, set of layers or finished print the temperature is raised to >60C to form NPs.

[0101] 0 Alternatively, the temperature of the bed is kept constant and heat is delivered from above each layer after each layer is printed (IR, UV lamps, etc).

[0102] In one example, jetting the first layer of the first powder with the first ink formulation comprises jetting the first layer of the first powder with the first ink formulation and a second (i.e. multiple) ink formulation, for example using respective (i.e. multiple) printheads.

[0103] Number of heads

[0104] 0 By adding more printheads, further inks could be added to mix multiple inks during print. This could be used to make a part with multiple gradients between different materials Print order optionally controlled o Ink A printed onto Ink B might produce a different material or microstructure than Ink B printed on Ink A.

[0105] Computer, computer program, non-transient computer-readable storage medium

[0106] The second aspect provides a computer comprising a processor and a memory configured to implement, at least in part, a method according to the first aspect, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the first aspect or a non-transient computer-readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the first aspect.

[0107] Article

[0108] The third aspect provides an article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation.

[0109] Method of ink jetting

[0110] The fourth aspect provides a method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation and a second ink formulation, thereby influencing a first microstructure of the first layer.

[0111] In this way, the first microstructure of the first layer is influenced, for example determined such as in combination with properties of the first powder, the first material, the first ink formulation, the second ink formulation and / or optionally post-processing such as heat treatment, by the first ink formulation and the second ink formulation (i.e. controlled). In this way, the microstructure of individual layers may be controlled interlayer. In this way, the microstructure of specific voxels may be controlled intralayer and / or interlayer.

[0112] The method according to the fourth aspect may include any step described with respect to the first aspect. In one example, the method comprises controlling binding of the first layer of the first powder by the first ink formulation and the second ink formulation comprising regulating forming of first particles from the first ink formulation and the second ink formulation in the first layer of the first powder.

[0113] In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises differentially jetting the first layer of the first powder with the first ink formulation and the second ink formulation. In this way, the first ink formulation and the second ink formulation are differentially jetted (for example, different dosings, jetting distances and / or jetting trajectories). In this way, jetting of the first ink formulation and the second ink formulation may be controlled individually, for example intralayer and / or interlayer.

[0114] In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises independently jetting the first layer of the first powder with the first ink formulation and the second ink formulation. In this way, the first layer is independently jetted with the first ink formulation and the second ink formulation, thereby allowing independent control thereof.

[0115] In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises simultaneously or successively jetting the first layer of the first powder with the first ink formulation and the second ink formulation. In this way, the first ink formulation and the second ink formulation may be co-jetted or alternately jetted, thereby enabling mixing during jetting or during permeation in the first layer, respectively, for example intralayer and / or interlayer.

[0116] In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises synchronising jetting the first layer of the first powder with the first ink formulation and the second ink formulation. In this way, the first ink formulation and the second ink formulation may be co-jetted or alternately jetted, thereby enabling mixing during jetting or during permeation in the first layer, respectively, for example intralayer and / or interlayer.

[0117] In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises modulating dosing of the first ink formulation and / or modulating dosing of the second ink formulation. In this way, the first ink formulation and the second ink formulation are differentially jetted (for example, different dosings). In this way, jetting of the first ink formulation and the second ink formulation may be controlled individually, for example intralayer and / or interlayer. In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises configuring jetting distances and / or jetting trajectories of the first ink formulation and / or the second ink formulation. In this way, the first ink formulation and the second ink formulation are differentially jetted (for example, different jetting distances and / or jetting trajectories). In this way, jetting of the first ink formulation and the second ink formulation may be controlled individually, for example intralayer and / or interlayer.

[0118] In one example, the method comprises mixing the first ink formulation and the second ink formulation, for example before, during and / or after jetting the first layer of the first powder with the first ink formulation and the second ink formulation. In this way, the first ink formulation and the second ink formulation may be mixed before jetting, during jetting or during permeation in the first layer, respectively, for example intralayer and / or interlayer.

[0119] In one example, mixing the first ink formulation and the second ink formulation during jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises mixing droplets of the first ink formulation and droplets of the second ink formulation during jetting the first layer of the first powder with the first ink formulation and the second ink formulation. In this way, the first ink formulation and the second ink formulation may be mixed during jetting, for example intralayer and / or interlayer.

[0120] In one example, mixing the first ink formulation and the second ink formulation after jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises mixing the first ink formulation and the second ink formulation in the first layer of the first powder, for example during permeation therethrough. In this way, the first ink formulation and the second ink formulation may be mixed during permeation in the first layer, for example intralayer and / or interlayer.

[0121] In one example, the method comprises mixing the first ink formulation and the second ink formulation, for example before, during and / or after jetting the first layer of the first powder with the first ink formulation and the second ink formulation; and wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises configuring jetting distances and / or jetting trajectories of the mixed ink formulation.

[0122] In this way, the first ink formulation and the second ink formulation may be mixed before jetting, during jetting or during permeation in the first layer, respectively, for example intralayer and / or interlayer, and jetting distances and / or jetting trajectories of the mixed ink formulation controlled, for example intralayer and / or interlayer. Mixing during jetting (i.e. mixing droplets in mid-flight) and mixing during permeation in the first layer facilitate the use of materials that are otherwise difficult, or impossible, to apply to jetting techniques. For example, the use of compositions that have an acceptable viscosity individually, but are too viscous in combination, such as two- part resins). Mixing during jetting enables better mixing of the first ink formulation and second ink formulation. Mixing during permeation enables gradients between the first ink formulation and second ink formulation within the layer (and / or between layers), which may otherwise be inaccessible.

[0123] Optionally controlling the dosage and mixing of inks prior to jetting or controlling the mixing of inks by combining drops from multiple nozzles at a controlled distance from the powder bed, wherein said distance includes zero, or a weighting of both methods, where said weighting can be between zero and 100% in each method. o In the cases of ink made of reactive components (i.e. when two or more components of the ink initiate or change the targeted reaction) the reactive components can be printed separately in 2 or more inks. Printheads for each ink can be aligned and angled towards each other. Each printhead can be any angle from -90 degrees (relative to the plane of the powderbed surface), through 0 degrees (parallel to the powderbed surface plane) to +90degrees relative to the powderbed surface. Printheads would be aligned in the y direction so that individual printnozzles are aligned and targeting the same point along each axis of the drop trajectory. Simultaneous drop ejection for aligned nozzles (in the case where each nozzle plate is the same distance from the point of intersection of the in-flight drops) or staggered firings (timings calculated by relative distances from the point of intersection of in-flight drops) would result in drops from each printhead merging in flight, possibly resulting in a new trajectory for the now combined drops. o The same arrangement could be used for 2 inks with different, singly reactive components (i.e. each ink not requiring the presence of the other to undergo the target reaction) to produce drop mixtures with variable compositions ranging from 0% to 100% for each ink. o The same arrangement could be used for one ink with active components and one ink Just consisting of carrier to produce controlled dilution of the active ink.

[0124] Optionally controlling the weighting between methods. o Control of the angles, offsets, ejection timings and ejection voltages could be achieved by reference to lookup tables, which store data from previously completed experiments. Alternatively they could be controlled in realtime by feedback from observation systems, observing the powderbed surface, the intersection point of merging drops or anywhere along any drop flight axis. Image recognition software could analyse the images to determine optimal adjustments to one of the above parameters. In one example, jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises introducing therein second particles comprising a second material, for example into the first ink formulation, the second ink formulation and / or droplets thereof. o For inks in which the addition of particles or nanoparticles can cause the target reaction to occur prematurely, or in cases where the particles or nanoparticles are difficult to suspend in the ink, particles or nanoparticles can be delivered into the ink just prior to drop ejection. The particles could be dry, surface coated or functionalized and / or in suspension in a carrier the same or different to that used for the ink. Particle delivery could be metered by a gate control system or pressure differential system to provide known quantities I densities of material to the ink.

[0125] In one example, the method comprises controlling rheology of the first ink formulation and / or the second ink formulation.

[0126] • In the cases of ink made of reactive components (i.e. when two or more components of the ink initiate or change the targeted reaction) the reactive components can be printed separately in 2 or more inks. Printheads for each ink can be aligned and angled towards each other. Each printhead can be any angle from -90 degrees (relative to the plane of the powderbed surface), through 0 degrees (parallel to the powderbed surface plane) to +90degrees relative to the powderbed surface. Printheads would be aligned in the y direction so that individual printnozzles are aligned and targeting the same point along each axis of the drop trajectory. Simultaneous drop ejection for aligned nozzles (in the case where each nozzle plate is the same distance from the point of intersection of the in-flight drops) or staggered firings (timings calculated by relative distances from the point of intersection of in-flight drops) would result in drops from each printhead merging in flight, possibly resulting in a new trajectory for the now combined drops.

[0127] • The same arrangement could be used for 2 inks with different, singly reactive components (i.e. each ink not requiring the presence of the other to undergo the target reaction) to produce drop mixtures with variable compositions ranging from 0% to 100% for each ink.

[0128] • The same arrangement could be used for one ink with active components and one ink Just consisting of carrier to produce controlled dilution of the active ink.

[0129] Computer, computer program, non-transient computer-readable storage medium

[0130] The fifth aspect provides a computer comprising a processor and a memory configured to implement, at least in part, a method according to the fourth aspect, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the fourth aspect or a non-transient computer-readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to the fourth aspect.

[0131] Article

[0132] The sixth aspect provides an article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation and a second ink formulation.

[0133] Method of ink jetting

[0134] The seventh aspect provides a method of ink jetting according to the first aspect and the fourth aspect.

[0135] Article

[0136] The eighth aspect provides an article according the second aspect and the fifth aspect.

[0137] Method of ink jetting

[0138] The ninth aspect provides a method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation, thereby influencing a first microstructure of the first layer; providing a second layer of the first powder comprising the first material; jetting the second layer of the first powder with a second ink formulation, thereby influencing a first microstructure of the first layer; comprising mixing the first ink formulation and the second ink formulation, for example after jetting the second layer of the first powder with the second ink formulation, for example during permeation therethrough to the first layer.

[0139] Apparatus

[0140] The tenth aspect provides an apparatus configured to implement the method according to the first aspect, the fourth aspect, the seventh aspect and / or the ninth aspect and / or to provide an article according to the third aspect and / or the eighth aspect. In one example, the apparatus is an adapted RICOH REACT 125 binder jet printer for the production of aluminium components. In one example, the apparatus includes an enclosure providing an inert atmosphere, for example down to 10 ppm O2. In one example, the apparatus includes a recirculation loop to remove contaminants. In one example, the apparatus includes a Midas ink recirculation system or similar. In one example, the apparatus includes a particle agitator to aid suspension. In one example, the apparatus includes a build platform such as a default 125 mm build platform that may be optionally increased in size. In one example, the apparatus includes a heated build plate, for example up to 60 °C, up to 80 °C, up to 100 °C, up to 200 °C or up to 300 °C.

[0141] Examples

[0142] Work hardened surface instead of a separate process.

[0143] 1 . Around a bolt hole for example.

[0144] Problem: Second part / process to insert sleave or reduce time for careful insertion.

[0145] Solution: part has work-hardened area to reduce impact effects and faster assembly.

[0146] 2. Break-points in part.

[0147] Problem: Non-deterministic break points can be removed by setting a defined break. Deterministic break failure result can be built in for over stress failure mechanism. Also for setting the life / fatigue lifetime of a part, or as an indication of life expiration.

[0148] Crystal: epitaxial growth. Piezo Resonance, pressure sensor, vibration.

[0149] 3. TiC>2 - as deposited goes down as amorphous with certain dielectric constant. With seed crystals deposition becomes anatase phase with higher dielectric constant.

[0150] Problem: Without this there may be stress within the product. Or might wish to have the stress built in. Or you can us a specific mode in the crystal. And 2D electron gas.

[0151] Surface: tribology: bearings / slide-guides, aerodynamic drag.

[0152] 4. Surface treatment for wear resistance or low friction.

[0153] Problem: Second part / process to make a bearing.

[0154] Solution: Treat surface to become a bushing / bearing.

[0155] Definitions

[0156] Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of’ or “consists essentially of’ means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention, such as colourants, and the like.

[0157] The term “consisting of’ or “consists of’ means including the components specified but excluding other components.

[0158] Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to include the meaning “consists essentially of” or “consisting essentially of’, and also may also be taken to include the meaning “consists of’ or “consisting of’.

[0159] The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention, as set out herein are also applicable to all other aspects or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each aspect or exemplary embodiment of the invention as interchangeable and combinable between different aspects and exemplary embodiments.

[0160] Brief description of the drawings

[0161] For a better understanding of the invention, and to show how exemplary embodiments of the same may be brought into effect, reference will be made, by way of example only, to the accompanying diagrammatic Figures, in which:

[0162] Figure 1 schematically depicts deposition and layering of jetted inks, according to an exemplary embodiment;

[0163] Figure 2 schematically depicts the effect of two different ink compositions on the resulting powder bed, according to an exemplary embodiment;

[0164] Figure 3 schematically depicts the effect of two different ink compositions on the resulting material microstructure, after consolidation, according to an exemplary embodiment;

[0165] Figure 4 schematically depicts different methods of ink mixing using at least one nozzle per ink, according to an exemplary embodiment; Figure 5 schematically depicts two inks of two different compositions that are deposited on different areas of the same powder bed, according to an exemplary embodiment;

[0166] Figure 6 schematically depicts ink permeation when using two inks of different composition, according to an exemplary embodiment;

[0167] Figure 7 schematically depicts the resulting permeation by two inks in the powder bed, according to an exemplary embodiment;

[0168] Figure 8 schematically depicts how the droplet size and frequency may be controlled, according to an exemplary embodiment;

[0169] Figure 9 schematically depicts how the inks can be deposited onto selected areas of the powder bed layer, according to an exemplary embodiment;

[0170] Figure 10 schematically depicts a powder bed particle size distribution, according to an exemplary embodiment;

[0171] Figure 11 schematically depicts a powder bed particle spherical distribution, according to an exemplary embodiment;

[0172] Figure 12 schematically depicts a typical temperature control flow diagram, according to an exemplary embodiment;

[0173] Figure 13 schematically depicts aspects related to an ink, according to an exemplary embodiment;

[0174] Figure 14 schematically depicts aspects related to a functional material, according to an exemplary embodiment;

[0175] Figure 15 schematically depicts a method according to an exemplary embodiment;

[0176] Figure 16 schematically depicts a method according to an exemplary embodiment;

[0177] Figure 17 schematically depicts a method according to an exemplary embodiment;

[0178] Figure 18 schematically depicts a method according to an exemplary embodiment; and

[0179] Figure 19 schematically depicts an apparatus according to an exemplary embodiment. Detailed Description of the Drawings

[0180] Flow diagram of layering inks: Copper Ink, one or two part Al ink, YSZ ink.

[0181] Turning to Figure 1 , diagram 100 shows the deposition of the first ink. The first ink is contained in the volume 109 and progresses through containing structures 108 to the print head 107 where it is jetted in a controlled fashion by way of one or more nozzles, 106. The resulting drops, 105, fall towards the powder layer, 103, to form a surface layer 104, which will permeate into the powder.

[0182] Figure 1 , diagram 101 , shows the completed surface coating of ink.

[0183] Figure 1 , diagram 102, shows the deposition of the second ink onto the first ink at the surface of the powder layer. The second ink is contained in the volume 113 and progresses through containing structures 112 to the print head where it is jetted in a controlled fashion by way of one or more nozzles. The resulting drops, 111 , fall towards the powder layer where they mix with the first ink. The time delay between the deposition of the first and second inks is controlled so that mixing of the inks may take place before or during the time ink one permeates into the powder.

[0184] Microstructure results of the above

[0185] Figure 2 schematically depicts the effect of two different ink compositions on the resulting powder bed.

[0186] Considering Figure 2, diagram 200 shows the deposition of a first ink and the effect of the ink compositions on the resulting powder bed. The ink is deposited onto the powder in a similar manner as was shown in Figure 1 diagram 100. Once the ink has permeated the powder, the layer consists of original powder, 202, and the either the entirety or parts of the ink, 203.

[0187] Figure 2, diagram 201 shows the deposition of a second ink and the effect of the ink compositions on the resulting powder bed. The ink is deposited onto the powder in a similar manner as was shown in Figure 1 diagram 100. Once the ink has permeated the powder, the layer consists of original powder and the either the entirety or parts of the ink, 204.

[0188] Figure 3 schematically depicts the effect of two different ink compositions on the resulting material microstructure, after consolidation. Considering Figure 3, diagram 300 represents the effect of a first ink composition on the resulting material microstructure, after consolidation. The representation of the resulting microstructure, 302, shows large microstructural elements have been produced.

[0189] Considering Figure 3, diagram 301 represents the effect of a second ink composition on the resulting material microstructure, after consolidation. The representation of the resulting microstructure, 302, shows smaller microstructural elements have been produced.

[0190] Independent jetting of inks including mix at head, in air, on surface or printed on top of each other, controlling the dosage & controlling weighting between methods.

[0191] Figure 4 schematically depicts different methods of ink mixing using at least one nozzle per ink.

[0192] Considering Figure 4, diagram 400, ink one, 405, and ink two, 406, are mixed within the containing structure that links the ink volume storage and the single print head. Thus creates the mixed ink, 404, which is jetted in a controlled fashion from one or more nozzles to form droplets, 403, that drop onto the surface of the powder layer.

[0193] Considering Figure 4, diagram 401 , ink one and ink two are kept separate until after each has been jetted from a separate nozzle. This creates ink one droplets, 409 and ink two droplets 410. The ink droplets collide to produce a droplet 407 and are mixed during their transit 408 towards the powder layer.

[0194] Considering Figure 4, diagram 402, ink one and ink two are kept separate until after each has been jetted from a separate nozzle. This creates ink one droplets and ink two droplets. The ink droplets collide at the powder bed surface 412 and may continue to mix as they permeate the powder layer.

[0195] Figure 5 schematically depicts two inks of two different compositions that are deposited on different areas of the same powder bed.

[0196] Considering Figure 5, diagram 500 which shows how droplets of ink one, 503, form a surface coating 502 on the powder bed and then subsequently, or concurrently, permeates the powder.

[0197] Considering Figure 5, diagram 501 which shows how droplets of ink two, 504, form a surface coating 506 on the powder bed which is not the same area as was coated by ink one, and then subsequently, or concurrently, permeates the powder.

[0198] Permeation Figure 6 schematically depicts ink permeation when using two inks of different composition.

[0199] Considering Figure 6, diagram 600, a layer of ink one, 605, on the powder bed is being created by droplets of ink one, 604, that have been jetted from a nozzle.

[0200] Considering Figure 6, diagram 601 , which shows ink one permeating through the powder during which material reactions may have begun based on just ink one.

[0201] Considering Figure 6, diagram 602, which shows ink one has permeated the powder layer while droplets of ink two, 606, are creating a surface coating of ink two, 607.

[0202] Considering Figure 6, diagram 603, which shows that ink two has started to permeate through the powder during which it mixes with ink one, or the semi (or completely) reacted material, and the material reaction may change or move to a different mode.

[0203] Figure 7 schematically depicts the resulting permeation by two inks in the powder bed.

[0204] Considering Figure 7, diagram 700, the two inks have created areas of differing ink to powder consistency based on no mixing of the inks.

[0205] Considering Figure 7, diagram 701 , the two inks have created areas of differing ink to powder consistency based on no mixing of the inks and on mixing of inks.

[0206] Considering Figure 7, diagram 702, the two inks have created areas of differing ink to powder consistency just based on the mixing of the inks.

[0207] Considering Figure 7, diagram 703, the two inks have created areas of differing ink to powder consistency based on no mixing of the inks and on a gradient mixing of the inks.

[0208] Considering Figure 7, diagram 704, the two inks have created areas of differing ink to powder consistency based only on a gradient mixing of the inks.

[0209] Systematic printing of the inks allows precise control of the quantity of ink delivered

[0210] Figure 8 schematically depicts how the droplet size and frequency may be controlled. Considering Figure 8, diagrams 801 which shows a graph of nozzle jet activation, 806, versus time, 807 from a print head, 802. And considering Figure 8, diagram 800, which shows a print head, 802, and different sizes of ink droplet, 803, 804 and 805.

[0211] The command signal, 808, has a large width in time and is associated with the largest droplet size, 805. The command signal, 809, has a medium width in time and is associated with the medium droplet size, 804. The command signal, 810, has a smaller width in time and is associated with the smallest droplet size, 803.

[0212] Patterns in deposition area

[0213] Figure 9 schematically depicts how the inks can be deposited onto selected areas of the powder bed layer.

[0214] Considering Figure 9, diagram 900, which shows a print head, 904, that has two nozzles, 906 and 907 which can in turn produce two separately controlled droplets, 905. The diagram shows when both nozzles fire at the same time and two parallel droplets are formed. Each droplet will fall on a separate section of powder bed layer.

[0215] Considering Figure 9, diagram 901 , which shows the same printed head an ink, however in this situation, the left nozzle has fired independently twice before both nozzles have fired. The action of the print head moving in the direction into the page results in two sections of the powder bed layer not receiving a droplet of ink.

[0216] Considering Figure 9, diagram 902, which shows how two inks can be deposited in different combinations on to different areas of the powder bed. Area 908 only has ink one deposition. Area 909 has no ink deposition. Area 910 has only ink two deposition and area 911 has both ink one and ink two deposition.

[0217] Considering Figure 9, diagram 903, which shows how the deposition of two inks can be varied in ratio. Area 912 has a small amount of ink one deposited. Area 913 has a small amount of ink two deposited. Area 914 has a large amount of ink one deposited. Area 915 has a medium amount of both inks deposited.

[0218] Powder bed particle size distribution determines packing, shapes, fill etc

[0219] Figure 10 schematically depicts powder bed particle size distribution. Considering Figure 10, each of the three rows show a powder bed composition on the left and a percentage of each particle side spread graph on the right.

[0220] Considering the top row of Figure 10, which shows a balanced blend of powder bed particle sizes. The middle row shows a particle size blend that is biased towards larger particles sizes. The lowest row shows a particle size blend that is biased towards smaller particles sizes.

[0221] Figure 1 1 schematically depicts powder bed particle spherical distribution.

[0222] Considering Figure 11 , each of the three rows show a powder bed composition on the left and a percentage of each particle sphericity spread graph on the right.

[0223] Considering the top row of Figure 10, which shows a balanced blend of powder bed particle sphericity. The middle row shows a particle sphericity blend that is biased towards more spherical particles sizes. The lowest row shows a particle sphericity blend that is biased towards less spherical particles sizes.

[0224] Flow diagram for controlling the temperature: effect on microstructure

[0225] Figure 12 schematically depicts a typical temperature control flow diagram.

[0226] Considering Figure 12, diagram 1200 shows a typical temperature control flow diagram. The material microstructure is altered from that of the green part 1201 through the first heating set temperature to the first structural change, 1202, to the second heating temperature resulting in the second structural change 1203. After cooling the microstructure is represented by 1204.

[0227] Figure 13 schematically depicts aspects related to an ink, according to an exemplary embodiment.

[0228] Figure 14 schematically depicts aspects related to a functional material, according to an exemplary embodiment.

[0229] Figure 15 schematically depicts a method according to an exemplary embodiment.

[0230] The method is of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material (S1501); jetting the first layer of the first powder with a first ink formulation (S1502); and controlling binding of the first layer of the first powder by the first ink formulation comprising regulating forming of first particles from the first ink formulation in the first layer of the first powder, thereby influencing a first microstructure of the first layer (S1503). Figure 16 schematically depicts a method according to an exemplary embodiment.

[0231] The method is of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material (S1601); jetting the first layer of the first powder with a first ink formulation and a second ink formulation, thereby influencing a first microstructure of the first layer (S1602).

[0232] Figure 17 schematically depicts a method according to an exemplary embodiment. Binder (i.e. ink) and nanoparticles permeate through the powder bed. The nano particles form in situ on the surface of the powder bed particles.

[0233] Figure 18 schematically depicts a method according to an exemplary embodiment. In-situ nanoparticle formation acts to bind the powder together with a non-sacrificial material. Nanoparticle formation can be controlled to create varied microstructure / properties throughout a part or article.

[0234] Figure 19 schematically depicts an apparatus according to an exemplary embodiment. The apparatus is configured to implement the method according to the first aspect, the fourth aspect, the seventh aspect and / or the ninth aspect and / or to provide an article according to the third aspect and / or the eighth aspect.

[0235] In this example, the apparatus is an adapted RICOH REACT 125 binder jet printer for the production of aluminium components. In this example, the apparatus includes an enclosure providing an inert atmosphere down to 10 ppm O2. In this example, the apparatus includes a recirculation loop removes contaminants. In this example, the apparatus includes a Midas ink recirculation system. In this example, the apparatus includes a particle agitator to aid suspension. In this example, the apparatus includes a default 125 mm build platform that may be optionally increased in size. In this example, the apparatus includes a heated build plate up to 80 °C.

[0236] Although a preferred embodiment has been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims and as described above.

[0237] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at most some of such features and / or steps are mutually exclusive.

[0238] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0239] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0240] Clauses of the Invention

[0241] Clause 1. A method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation; and controlling binding of the first layer of the first powder by the first ink formulation comprising regulating forming of first particles from the first ink formulation in the first layer of the first powder, thereby influencing a first microstructure of the first layer.

[0242] Clause 2. The method according to any previous clause, wherein the first ink formulation comprises a solvent, a catalyst, a precursor material, a carrier vehicle, a growth agent and / or an inhibitor.

[0243] Clause 3. The method according to any previous clause, wherein the first particles comprise nanoparticles.

[0244] Clause 4. The method according to any previous clause, wherein regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises regulating forming of the first particles from the first ink formulation and the first powder in the first layer of the first powder and / or regulating forming of the first particles from the first ink formulation on the first powder in the first layer.

[0245] Clause 5. The method according to any previous clause, wherein regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises modulating dosing of the first ink formulation.

[0246] Clause 6. The method according to any previous clause, comprising selecting a particle size distribution of the first powder.

[0247] Clause 7. The method according to any previous clause, comprising selecting a particle morphology of the first powder.

[0248] Clause 8. The method according to any previous clause, wherein regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises exposing the first layer of the first powder and / or the first ink formulation to a first atmosphere.

[0249] Clause 9. The method according to any previous clause, wherein regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises heating the first layer of the first powder and / or the first ink formulation, for example before, during and / after jetting the first layer of the first powder with the first ink formulation.

[0250] Clause 10. The method according to any previous clause, wherein: jetting the first layer of the first powder with the first ink formulation comprises jetting the first layer of the first powder with the first ink formulation and a second ink formulation; and wherein regulating forming of first particles from the first ink formulation in the first layer of the first powder comprises regulating forming of first particles from the first ink formulation and the second ink formulation in the first layer of the first powder.

[0251] Clause 11 . The method according to any previous clause, wherein regulating forming of the first particles from the first ink formulation in the first layer of the first powder comprises respectively regulating forming of the first particles from the first ink formulation in mutually adjacent voxels of the first layer of the first powder.

[0252] Clause 12. The method according to any previous clause, wherein: jetting the first layer of the first powder with the first ink formulation comprises jetting the first layer of the first powder with the first ink formulation and a second ink formulation; and wherein regulating forming of first particles from the first ink formulation in the first layer of the first powder comprises respectively regulating forming of the first particles from the first ink formulation and the second ink formulation in mutually adjacent voxels of the first layer of the first powder.

[0253] Clause 13. The method according to any previous clause, comprising: providing a second layer of the first powder comprising the first material; jetting on to the second layer of the first powder with the first ink formulation; and controlling binding of the second layer of the first powder by the first ink formulation comprising regulating forming of the first particles from the first ink formulation in the second layer of the first powder, thereby influencing a second microstructure of the second layer; wherein the first microstructure and the second microstructure are mutually different.

[0254] Clause 14. A computer comprising a processor and a memory configured to implement a method according to any of clauses 1 to 13, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method according to any of clauses 1 to 13 or a non-transient computer-readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method according to any of clauses 1 to 13.

[0255] Clause 15. An article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation.

[0256] Clause 16. A method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation and a second ink formulation, thereby influencing a first microstructure of the first layer.

[0257] Clause 17. The method according to clause 16, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises differentially jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

[0258] Clause 18. The method according to any of clauses 16 to 17, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises independently jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

[0259] Clause 19. The method according to any of clauses 16 to 18, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises simultaneously or successively jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

[0260] Clause 20. The method according to any of clauses 16 to 19, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises synchronising jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

[0261] Clause 21 . The method according to any of clauses 16 to 20, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises modulating dosing of the first ink formulation and / or modulating dosing of the second ink formulation.

[0262] Clause 22. The method according to any of clauses 16 to 21 , wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises configuring jetting distances and / or jetting trajectories of the first ink formulation and / or the second ink formulation.

[0263] Clause 23. The method according to any of clauses 16 to 22, comprising mixing the first ink formulation and the second ink formulation, for example before, during and / or after jetting the first layer of the first powder with the first ink formulation and the second ink formulation. Clause 24. The method according to clause 23, wherein mixing the first ink formulation and the second ink formulation during jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises mixing droplets of the first ink formulation and droplets of the second ink formulation during jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

[0264] Clause 25. The method according to any of clauses 23 to 24, wherein mixing the first ink formulation and the second ink formulation after jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises mixing the first ink formulation and the second ink formulation in the first layer of the first powder, for example during permeation therethrough.

[0265] Clause 26. The method according to any of clauses 16 to 25, comprising mixing the first ink formulation and the second ink formulation, for example before, during and / or after jetting the first layer of the first powder with the first ink formulation and the second ink formulation; and wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises configuring jetting distances and / or jetting trajectories of the mixed ink formulation.

[0266] Clause 27. The method according to any of clauses 16 to 26, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises introducing therein second particles comprising a second material, for example into the first ink formulation, the second ink formulation and / or droplets thereof.

[0267] Clause 28. A method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation, thereby influencing a first microstructure of the first layer; providing a second layer of the first powder comprising the first material; jetting the second layer of the first powder with a second ink formulation, thereby influencing a first microstructure of the first layer; comprising mixing the first ink formulation and the second ink formulation, for example after jetting the second layer of the first powder with the second ink formulation, for example during permeation therethrough to the first layer.

[0268] Clause 29. A computer comprising a processor and a memory configured to implement a method according to any of clauses 16 to 29, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method according to any of clauses 16 to 29 or a non-transient computer-readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method according to any of clauses 16 to 29. Clause 30. An article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation and a second ink formulation.

Claims

CLAIMS1. A method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation and a second ink formulation, thereby influencing a first microstructure of the first layer.

2. The method according to claim 1 , wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises differentially jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

3. The method according to any previous claim, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises independently jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

4. The method according to any previous claim, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises simultaneously or successively jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

5. The method according to any previous claim, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises synchronising jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

6. The method according to any previous claim, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises modulating dosing of the first ink formulation and / or modulating dosing of the second ink formulation.

7. The method according to any previous claim, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises configuring jetting distances and / or jetting trajectories of the first ink formulation and / or the second ink formulation.

8. The method according to any previous claim, comprising mixing the first ink formulation and the second ink formulation, for example before, during and / or after jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

9. The method according to claim 8, wherein mixing the first ink formulation and the second ink formulation during jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises mixing droplets of the first ink formulation and droplets of thesecond ink formulation during jetting the first layer of the first powder with the first ink formulation and the second ink formulation.

10. The method according to any of claims 8 to 9, wherein mixing the first ink formulation and the second ink formulation after jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises mixing the first ink formulation and the second ink formulation in the first layer of the first powder, for example during permeation therethrough.11 . The method according to any previous claim, comprising mixing the first ink formulation and the second ink formulation, for example before, during and / or after jetting the first layer of the first powder with the first ink formulation and the second ink formulation; and wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises configuring jetting distances and / or jetting trajectories of the mixed ink formulation.

12. The method according to any previous claim, wherein jetting the first layer of the first powder with the first ink formulation and the second ink formulation comprises introducing therein second particles comprising a second material, for example into the first ink formulation, the second ink formulation and / or droplets thereof.

13. A method of ink jetting, the method comprising: providing a first layer of a first powder comprising a first material; jetting the first layer of the first powder with a first ink formulation, thereby influencing a first microstructure of the first layer; providing a second layer of the first powder comprising the first material; jetting the second layer of the first powder with a second ink formulation, thereby influencing a first microstructure of the first layer; comprising mixing the first ink formulation and the second ink formulation, for example after jetting the second layer of the first powder with the second ink formulation, for example during permeation therethrough to the first layer.

14. A computer comprising a processor and a memory configured to implement, at least in part, a method according to any of claims 1 to 13, a computer program comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to any of claims 1 to 13 or a non-transient computer- readable storage medium comprising instructions which, when executed by a computer comprising a processor and a memory, cause the computer to perform a method, at least in part, according to any of claims 1 to 13.

15. An article manufactured at least in part by ink jetting, the article comprising: a first layer of a bound first powder comprising a first material; wherein the first layer comprises: a first microstructure influenced by first particles formed from a first ink formulation and a second ink formulation.

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