GB2616872A - A method of manufacturing a canister for use in hot isostatic pressing - Google Patents

Abstract

A method of manufacturing a canister (45, Fig. 6) for use in a hot isostatic pressing (HIP) process for the manufacture of near net shape components, comprising electroplating an electrically prepared mandrel 25 in an electrolyte bath 15, using a current density between 0.01-0.05 A/m2, to form a canister (45) with the same profile as the mandrel 25, and removing the mandrel 25. A method of manufacturing the canister (50) is disclosed wherein the mandrel 25 is coated via chemical vapor deposition (CVD) to form a canister (45) with the same profile as the mandrel 25, and removing the mandrel 25. A method of manufacturing a part (60, Fig. 8) using HIP, comprising filling the canister (45) from previous methods with powder (55, Fig. 7), consolidating the powder (55) to form a part (60), and removing the canister (45). A method of processing a design drawing of a finished part, comprising extracting the surface area from a design drawing of a finished part; increasing the surface area by 5-10%; creating an amended design drawing of an initial part having the increased surface area, and outputting the amended design drawing for manufacturing the finished part according to a manufacturing process.

Description

A METHOD OF MANUFACTURING A CANISTER FOR USE IN HOT ISOSTATIC

PRESSING

[0001] The present invention relates to a method of manufacturing a canister for use in a hot isostatic pressing process for the manufacture of near net shape components.

BACKGROUND

[0002] A number of methods to produce replicate components from a finished example are widely known, including the use of metal casting, forging, and machining. These methods of producing replicate components are however found to be unsuitable for the production of complex shaped components, material intensive, and inflexible to alterations to the finished component's specification. An improved process, which overcomes these issues, by utilising additive manufacture, electroforming, and powder metallurgy to produce near net shape components is proposed. Wherein, near net shape components are components that require little further manufacturing to reach a finished state.

BRIEF SUMMARY OF THE DISCLOSURE

[0003] In accordance with the present disclosure there is provided a method of manufacturing a canister for use in a hot isostatic pressing process for the manufacture of near net shape components, the method comprising: providing an electrically prepared mandrel in a bath comprising electrolytes for electroplating the mandrel; electroplating the mandrel to form a canister for use in a hot isostatic pressing process using an electrical current density between 0.01 A/m2 and 0.05 A/m2, wherein the canister has a profile corresponding to a profile of the mandrel, and; removing the mandrel from the canister.

[0004] This advantageously provides a method of forming a canister having a substantially uniform thickness across the mandrel, which may have a complex profile.

[0005] The mandrel may comprise an electrically conductive coating. The electrically conductive coating may be applied by painting or by dipping the mandrel into a pre-dipping solution. The mandrel, produced through an additive manufacturing process, may comprise a polymer or metallic based material. The mandrel may comprise a polymer material, such as high impact polystyrene or machining wax, or a metallic material, such as steel. Where the mandrel is manufactured using metallic materials, the mandrel may be recyclable and therefore beneficial for serial production of parts.

[0006] The electrically conductive coating may comprise a coating material comprising any of graphite, nickel or silver. The electrically conductive coating may comprise a release agent.

[0007] The mandrel may comprise a cathode. The bath may comprise one or more anodes for electroplating the mandrel. The one or more anodes may include an internal anode. At least one of the one or more anodes may be disposed within the mandrel, for example within an internal cavity of the mandrel.

[0008] The bath of electrolytes may be agitated as the mandrel is electroplated. The bath of electrolytes may comprise a sulphamate solution or a sulphate solution. The sulphamate solution may comprise any of nickel or cobalt. The sulphate solution may comprise any of bronze or copper.. The electrolytes may comprise metal ions.

[0009] The current density may be varied as the mandrel is electroplated. The current density may be increased from a first current density to a second current density. This advantageously allows an initial seed layer to be established on the mandrel before the remaining canister thickness is formed on the seed layer in a more efficient manner. The first current density may be approximately half the second current density. The second current density may be between 0.025A/m2and 0.05A/m2. In some cases, the increase from the first current density to the second current density is substantially instantaneous. The mandrel may be electroplated at the first current density for approximately one hour.

[0010] The canister may be electroplated to a thickness of at least 1 mm.

[0011] The mandrel may be removed from the canister by at least partially deforming the mandrel. In some cases, the mandrel is at least partially melted. In some cases, the mandrel is at least partially dissolved. The mandrel may be heated to between 10000 and 250 °C to release the canister. The mandrel may be heated to between 120 °C and 250 °C to release the canister. In some cases, the mandrel is at least partially dissolved using a chemical. In some cases the mandrel is at least partially dissolved using a mineral acid. Dissolving the mandrel is particularly advantageous when the mandrel is made from a polymer material, such as high impact polystyrene.

[0012] The method may comprise the step of placing the formed canister in an ultrasonic bath to remove residue on the canister. The ultrasonic bath may comprise a mineral acid. In some cases, the mineral acid is a limonene solution, for example a (R)-limonene solution.

[0013] The method may comprise welding one or more tubes to the canister for evacuating air from the canister.

[0014] Viewed from a further independent aspect, there is also provided a method of manufacturing a canister for use in a hot isostatic pressing process for the manufacture of near net shape components, the method comprising: coating the mandrel to form a canister for use in a hot isostatic pressing process, wherein the canister has a profile corresponding to a profile of the mandrel, and removing the mandrel from the canister. This advantageously provides a method of forming a canister having a substantially uniform thickness across the mandrel, which may have a complex profile. The mandrel may be coated using chemical vapor deposition or electroplating.

[0015] The mandrel may be coated with a coating material comprising any of tantalum or niobium or an alloy thereof.

[0016] Viewed from a further independent aspect, there is also provided a method of manufacturing a part using a hot isostatic pressing process, the method comprising: providing a canister according to any of the preceding claims; filling the canister with powder; consolidating the powder to form a part, and; removing the canister from the part.

[0017] Prior to filling with powder, a release agent may be applied to the inside of the canister.

[0018] The method may comprise checking the canister for vacuum tightness using a helium leak detector.

[0019] The filled canister may be vibrated to increase the packing density of the powder.

The powder may be a metallic or polymer powder. The powder may have a mean (e.g. d50) particle size of 90pm. In some cases, the powder has a maximum particle size of 300pm.

[0020] Air may be vacated from the filled canister using a vacuum pump. The canister may be evacuated to a pressure of 0.6 Pa. The method may comprise crimping and heating the one or more tubes to maintain a vacuum in the canister. The method may comprise partially filling the one or more tubes with a chemically reactive getter material for maintaining the vacuum. The getter material may be reactive to oxygen and nitrogen. This advantageously maintains a lower level of vacuum in the canister.

[0021] Removing the canister may comprise machining the canister off the part.

[0022] Viewed from a further independent aspect, there is also provided a method of processing a design drawing of a finished part, the method comprising: from a design drawing of a finished part having a surface area, extracting the surface area from the design drawing; increasing the surface area of the finished part between 5% and 10%; creating an amended design drawing of an initial part having the increased surface area, and; outputting the amended design drawing for manufacturing the finished part according to a manufacturing process.

[0023] This advantageously provides an amended design drawing which account for the shrinkage of the initial part during the manufacturing process, such as a hot isostatic pressing process. As such, the finished parts produced using the initial part, which may be a canister, require considerably less processing in order to meet the tolerances of the desired finished part. The surface area may be increased based on any of a property of the powder, such as powder density, a maximum particle size of the powder, and a material density of the powder. The powder may be a metallic powder. The surface area may be increased based on any geometric property, such as a linear dimension, of the finished part.

[0024] Creating the amended design may comprise introducing a hollow core in the initial part. Creating the amended design may comprise introducing a reinforcing element in the initial part. The reinforcing element may be any of a strut or truss or similar load-bearing element to support the profile of the initial during the manufacturing process.

[0025] Creating the amended design may comprises introducing a fixture into the initial part for holding the anode relative to the initial part. The fixture may be arranged to hold the anode off a surface of the initial part.

[0026] Increasing the surface area comprises increasing a dimension of the finished part by between 5% and 10%.

[0027] The manufacturing process may be an additive manufacturing process.

[0028] The method may comprise the steps of scanning the finished part to obtain geometry data of the finished part, and; creating the design drawing from the geometry data. wherein the geometry data comprises the surface area.

[0029] Viewed from a further independent aspect, there is also provided a method of manufacturing a canister for use in a hot isostatic pressing process by providing a electrically prepared mandrel in a bath comprising electrolytes for electroplating the mandrel and electroplating the mandrel to form a canister for use in a hot isostatic pressing process, wherein the canister has a profile corresponding to a profile of the mandrel, and removing the mandrel from the canister.

[0030] Viewed from a further independent aspect, there is also provided a method of manufacturing a finished component using a method described herein.

[0031] Viewed from a further independent aspect, there is also provided a canister manufactured according to any of the methods described herein.

[0032] Viewed from a further independent aspect, there is also provided a finished part manufactured according to any of the methods described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates an exemplary process for manufacturing a finished part; Figure 2 illustrates an exemplary process for preparing a design drawing for use in the process of Figure 1 Figures 3 illustrates an exemplary process for manufacturing a canister for use in the process of Figure 1 Figure 4 is a schematic illustration of an exemplary bath for coating a mandrel; Figure 5 is a schematic illustration of an exemplary mandrel with a metal layer formed thereon; Figure 6 is a schematic illustration of an exemplary canister; Figure 7 is a schematic illustration of the canister of Figure 6 filled with a metallic powder, Figure 8 is a schematic illustration of the canister of Figure 7 where the metallic powder has been consolidated the canister, and Figure 9 is a schematic illustration of an exemplary process for removing the canister from the finished part.

DETAILED DESCRIPTION

[0033] Figure 1 illustrates an exemplary process 10 for manufacturing a finished part. With is reference to Figure 2, the process 10 includes providing 100 a design drawing, typically a computer aided design file, of a mandrel 25 (see also Figure 5) which has a geometry that corresponds to the geometry of the finished part. It should be noted that the geometry of the mandrel 25 is not identical to that of the finished part, as the manufacturing processes described herein result in varying amounts of shrinkage of the part relative to the geometry of the mandrel 25. As explained below, the present application provides a way of amending the design drawing of the finished part which results in considerably less processing of the finished part, which in turn results in less wastage of material.

[0034] A design drawing file of the finished part may be provided by a first user to a second user for manufacturing a suitable mandrel 25. The design drawing is preferably generated using computer aided design software. Where no design drawings exist, a design drawing can be developed by scanning 105 a finished part to obtain geometric data, and subsequently creating 110 a design drawing of the finished part. It would be apparent that the first user may only have the finished part and would provide this to the second user for scanning to obtain the design drawing of the finished part for amending 115.

[0035] The design drawing has a geometry including number of surfaces defined by respective dimensions, such as lengths and areas. The overall volume of the whole finished part, or parts thereof, may also be extracted from the design drawing. Where the design drawing is created by scanning a finished part, the geometric data includes the dimension which can be extracted and amended based on design considerations.

[0036] As explained above, in manufacturing processes such as hot isostafic pressing, there will be some degree of shrinkage of the finished part compared to the design drawing of the mandrel (which can be considered an initial part). The degree of shrinkage is dependent on the relative density of the material used to form the mandrel, and on the geometry, e.g. the volume and surface area, of the mandrel. As volume and surface area vary in a non-linear manner for a given geometry, the specific degree of shrinkage will depend on the geometry of the mandrel. It is therefore desirable to amend 115 the design drawing of the finished part account for this shrinkage to reduce the amount of wastage of the materials used to make the finished part. It has been found that increasing the surface area of the finished part by between 5% and 10% is sufficient to account for shrinkage of most parts. However, it would be apparent this was merely exemplary, and that the level of shrinkage will be dependent on various properties of the finished part such as its geometry (e.g. dimensions and areas) and what material the finished part is to be made from (e.g. powder densities, material density, powder particle size).

[0037] Depending on the geometry of the finished part, it is also possible to amend the design drawing to include 120 further structural elements. These structural elements may be temporary (i.e. not part of the finished part) and facilitate manufacturing of the canister or the finished part, or may be permanent (i.e. remain as part of the finished part). For example, a hollow core in the mandrel 25 to allow an internal anode used to electroplate the mandrel 25 to be located within the hollow core. Where an internal anode is to be used, the design drawing can be amended to introduce fixtures to secure the internal anode within the hollow core. It would be apparent that while a core is described, it would not be essential that the core extends through the thickness of the mandrel 25, and that in some cases, the core may only extend partially through the thickness of the mandrel 25. Where the mandrel 25 is expected to carry a load at specific locations, the design drawing can be amended to include a reinforcing element, such as a strut or truss element. Reinforcing elements may be located where the finished part will support a load, such as where the finished part joins a product hanger.

[0038] Based on the amended geometry of the finished part, an amended design drawing of the mandrel 25 is created 125. The amended drawing can then be output 130 in a suitable format for use in a subsequent manufacturing process, such as an additive manufacturing process, to create 200 the mandrel 25. Additive manufacturing processes, such as 3D printing, are particularly advantageous as these allow for the creation of complex three dimensional profiles which would otherwise be impractical to manufacturing using conventional canister fabrication techniques. Preferably, a fused deposition modelling three-dimensional printer is used. Amending the design drawing in this way provides a more efficient design process which is particularly suited for rapid prototyping complex, low volume parts which have previously been uneconomical to produce using traditional manufacturing processes. While a polymer mandrel is preferable, it would be apparent this was not essential, and the mandrel 25 may be made out of metals, such as steel, to allow for serial production of canisters. The mandrel 25 has a form that makes it suitable for coating using the processes described below. In some cases the polymer mandrel is made of high impact polystyrene or a machining wax.

[0039] Creating 200 the mandrel 25 can include the step of preparing the mandrel 25 for coating 300 to form the canister 50 (see Figure 5). In one example, the mandrel 25 is electrically prepared by dipping in one or more pre-dip solutions or painted with a conductive paint. The electrically conductive coating 40 may result in a metallic electroless finish once the mandrel 25 has been electroplated. An electrically conductive coating 40 comprising any of graphite, nickel or silver have been found to be particularly effective. A release agent can be added to the electrically conductive coating 40 to facilitate removal of the mandrel 25 in subsequent manufacturing processes. However, it would be apparent that this was not essential. The step of preparing the mandrel 25 can also include connecting the coated mandrel 25 to a negative terminal 22 so that the mandrel 25 acts as a cathode in the electrolyte bath 15. An electrically prepared mandrel 25 can then be coated by electroplating the mandrel 25 in an electrolyte bath 15 (see Figure 5) as explained below.

[0040] With reference to Figure 3, an exemplary method of manufacturing 300 the canister includes providing 305 an electrically prepared mandrel 25 as described above. Inserting 310 the electrically prepared mandrel 25 into the electrolyte bath 15 and applying 315 a voltage across respective positive 21 and negative 22 terminals will cause the conductive mandrel 25 (acting as a cathode) to attract metal ions within the electrolyte bath 15 to the conductive layer 40. Over time, the metal ions will form a metal layer 50 over the conductive layer 40 which will ultimately form the canister 45.

[0041] It would be apparent that different metal ions could be present in the electrolyte bath 15 to form canisters 45 made of different metals. As such, it would be apparent the examples described below are not essential to the present method. The electrolyte bath 15 may comprise a sulphamate solution, such as nickel sulphamate or cobalt sulphamate, to provide a nickel or cobalt canister. Alternatively, the electrolyte bath 15 may comprise a sulphate solution, such as bronze sulphate or copper sulphate, to provide a bronze or copper canister. It has been found that by using a relatively low current density initially, it is possible to establish 320 a seed layer on the mandrel 25, before increasing 325 the current density to a higher level to more efficiently establish the metal layer 50 on the mandrel 25. The initial current density may be approximately half the current density of the higher (stead state) level. A steady state current density of between 0.025A/m2 and 0.05A/m2 has been found to be particularly effective, but it would be apparent this will depend on the plating materials. In some cases the initial level may be less than half the steady state level. It would also be apparent that while the change from the initial currently density level to the steady state current density level may be implemented as a single step (e.g. by manually increasing a dial or switch), this was not essential and in some cases, it may be desirable to vary the current density in other ways to ensure proper coverage of the mandrel 25 with the metal layer. The mandrel 25 can be plated for a period of time using electrical current densities calculated specifically for the finished part. The current density may be changed during plating depending on the complexity of the part geometry. For example, the initial seed layer may take an hour to form when a current density of approximately 0.01A/m2 is applied. By controlling the current density level and the duration of electroplating, it is possible to control the thickness of the metal layer 50 formed on the mandrel 25. Plating the mandrel 25 to a thickness of at least 1mm is preferred. The thickness of the metal layer 50 may however is vary over the body of the mandrel 25, dependent on the complexity of mandrel 25 geometry.

For a mandrel 25 having a complex geometry, particularly with internal and external corners, the majority of the surface may have a metal layer 50 with a thickness of a first value (e.g. 1.5mm). However, at an internal corner, the metal layer 50 thickness will typically be less than the first value (e.g. 1mm), as the internal corner restricts the ability of the metal ions to adhere to the underlying mandrel 25. Conversely, at external corners, the metal layer 50 will typically have a thickness that is larger than the first value (e.g. 2mm), The thickness of the resulting canister 45 may be checked using a hand held device, such as an ultrasonic device.

[0042] It has also been found that by agitating the bath of electrolytes 15 as the mandrel 25 is electroplated, for example using eductors (not shown), this minimises deleterious surface features and porosity cause by entrapped hydrogen molecules. With reference to Figure 5, while a single external anode 20 is shown, it would be apparent that multiple anodes 20 may be provided in the electrolyte bath 15, to provide a more efficient plating process. Furthermore, the anodes 20 may be arranged around and/or within the mandrel 25 to ensure proper coverage of the conductive layer with the metal layer. Fixtures (not shown) on the mandrel 25 can be used to accurately locate the anodes 20 in pre-determined positions relative to the mandrel 25 surface, such as within a hollow core 35 of the mandrel 25. In some cases, the bath may include a cover or holder for holding the anodes 20 in the pre-determined positions.

[0043] In an alternative example, the mandrel 25 is coated by chemical vapor deposition. This provides a way of coating the mandrel 25 with metals which cannot be electroplated, such as tantalum or niobium, or alloys thereof [0044] Once a sufficiently thick metal layer 50 has formed on the mandrel 25 (see Figure 5), the mandrel 25 can be removed from the bath of electrolytes and the metal layer 50 removed from the mandrel 25. This can be achieved by partially deforming the mandrel 25, for example by melting or dissolving, to allow the mandrel 25 to be released from the metal layer 50 formed thereon. A release agent, if present, will facilitate this removal. The metal layer 50 without the mandrel 25 is shown as a canister 45 in Figure 6.

[0045] Where the mandrel 25 is made of a polymer, the mandrel can be heated to between 100°C and 250°C to melt the mandrel 25. This can be achieved in an oven. In some cases, melting the mandrel will leave a polymer residue on the inside of the canister 45. The polymer residue may be removed by introducing the canister 45 into a bath of mineral acid and dissolving the polymer residual material. This effect can be enhanced where the bath is an ultrasonic bath. Preferably, the mineral acid is a limonene solution, for example a (R)-limonene solution. The canister may be placed in the ultrasonic bath for up to 24 hours to remove the polymer residue. In some cases, it is not necessary to melt the mandrel 25, and the polymer mandrel 25 may be removed from the canister by dissolving the mandrel using a bath of mineral acid. This bath may be the same bath that is used to remove polymer residue described above. The canister 45 can be checked for any residual polymer material with a borescope.

[0046] If the mandrel is made of metal, for example machined steel, the mandrel 25 is released from the mandrel 25, optionally facilitated by a release agent, and can be re-used to form further canisters as described above. This advantageously, reduces wastage in the manufacturing process.

[0047] Once the canister 45 is removed from the mandrel 25, one or more tubes are welded 330 to the canister 45. different types of tubes are welded to the canister 45. Exemplary tubes include those suitable for filling a canister with a powder (filling tubes), and tubes suitable for evacuating air from the canister (evacuation tubes). It would be apparent this step was not essential to the process of coating the mandrel 25.

[0048] Once the tubes are welded to the canister, the canister may be checked for vacuum tightness. Vacuum tightness may be checked using a helium leak detector, or alternative methods. Where a helium leak detector is used, the pressure may be set within the range of 10-10 to 10' millibar. Where leaks are found, these leaks can be remediated accordingly.

[0049] The combination of a 3D printed mandrel 25 and the coating processes 300 described above, result in canisters 45 that have a considerably more intricate shape compared to traditional canister fabrication techniques. A further advantage of the present coating processes, is that the canister 45 can be made as a single piece (i.e. be of unitary construction), or can be formed of multiple sections, and combined in subsequent manufacturing processes, for example by welding the sections together. A further advantage of the present method of manufacturing the canister 45, is that the canister 45 has a profile that is much closer in geometry to the finished part than is achieved through conventional fabrication techniques. Thus, there is less wastage in the manufacturing process. For example, where a pure nickel canister 45 is used, this can be recycled.

[0050] With reference to Figures 6 and 7, the canister 45 can then be filled 400 with a powder 55 to form the finished part in the desired material. It would be apparent the powder used to form the finished part can comprise any of a polymer or a metal, and will have parameters to identify aspects of the powder, such as a maximum particle size, a material density and a mean particular size (e.g. a d50 size). Prior to filling the canister with powder, a release agent may be applied to the inside of the canister. The release agent facilitates the removal of the canister from the finished part in subsequent manufacturing processes. A wide range of high performance metallic powders may be used in the consolidation process. Example metallic powders may include, but are not limited to, titanium, steel, aluminium, and alloys. By way of example, a mean (d50) particle size of 90 pm and a maximum particle size of 300 pm.

[0051] The powder 55 is decanted into the canister 45 via a funnel and a filling tube (e.g. one of the tubes attached to the canister 45 described above). The amount of powder 55 used to fill the canister 45 is calculated based on the tap density of powder 55. The canister 45 may be vibrated as it is filled to increase the packing density of the powder 55.

[0052] Once the canister 45 is filled 400 with the desired amount of powder 55, the filling tube is partially filled with a getter material to maintain a lower vacuum level within the canister during the subsequent consolidation process. The getter material may be reactive to oxygen and/or nitrogen. The filling tubes are sealed via appropriate means, including heating and crimping.

[0053] A vacuum pump is attached to the evacuation tubes to evacuate the air from the canister 45. A vacuum pressure of approximately 0.6 Pa has been found to be suitable. To ensure the vacuum is maintained within the canister 45, the evacuation tubes are sealed via appropriate means, including heating and crimping. The filling tubes can also be sealed while the evacuation tubes are connected to the vacuum pump.

[0054] Once the canister 45 is sealed and evacuated, heat and pressure is applied to consolidate 500 the powder 55 within the canister 45. A hot isostatic pressing process is one example of a consolidation process 500 found to be suitable for use with the present method. It would be apparent that the temperatures and pressures applied will be dependent on the powder 55 used. Additional heat treatment steps can be included as part of the consolidation process 500. With reference to Figures 8 and 9, the consolidated material 60 has a geometry that corresponds to the finished part, but is smaller than that of the raw powder 55.

[0055] The canister 45 is then removed 600 from the consolidated material 60. Where the consolidated material 60 does not require any further processing, it may be considered as the finished part once it is removed from the canister 45. In some cases the consolidated material 60 may require minor processing 700 (e.g. machining) to achieve the dimensional tolerances of the finished part. In some cases, the release agent allows for the consolidated material 60 to be removed directly from the canister 45. In some cases, it is necessary to machine some or all of the canister 45 off the consolidated material 60. In some cases, targeted parts of the canister 45 are machined away to allow the canister 45 to be pealed away, or otherwise detached from, the consolidated material 60. Machining may be performed by a multi-axis machine 65, or similar processes.

[0056] The finished part is inspected 800, for example by measuring the dimensions of the finished part, for adherence to a customer specification. The finished part exhibits excellent mechanical properties and enables a light-weighting re-design process.

Claims (1)

1. CLAIMS1. A method of manufacturing a canister for use in a hot isostatic pressing process for the manufacture of near net shape components, the method comprising: providing an electrically prepared mandrel in a bath comprising electrolytes for electroplating the mandrel; electroplating the mandrel to form a canister for use in a hot isostatic pressing process using an electrical current density between 0.01 Atm' and 0.05 A/m2, wherein the canister has a profile corresponding to a profile of the mandrel, and; removing the mandrel from the canister.to 2. A method according to claim 1, wherein the mandrel comprises an electrically conductive coating applied by painting or by dipping the mandrel into a pre-dipping solution.3. A method according to any preceding claim, wherein the mandrel comprises a cathode, and wherein the bath comprises one or more anodes for electroplating the mandrel.4. A method according to any preceding claim, wherein the bath of electrolytes is agitated as the mandrel is electroplated.5. A method according to any preceding claim, wherein the bath of electrolytes comprises a sulphamate solution or a sulphate solution.6. A method according to any preceding claim, wherein the current density is varied as the mandrel is electroplated.7. A method according to any preceding claim, wherein the canister is electroplated to a thickness of at least 1 mm.8. A method according to any preceding claim, wherein the mandrel is removed from the canister by at least partially deforming the mandrel.9. A method according to any preceding claim, comprising the step of placing the formed canister in an ultrasonic bath to remove residue on the canister.10. A method according to any preceding claim, comprising welding one or more tubes to the canister for evacuating air from the canister.11. A method of manufacturing a canister for use in a hot isostatic pressing process for the manufacture of near net shape components, the method comprising: providing a mandrel coating a mandrel having a profile corresponding to a profile of a finished part, forming a canister for use in a hot isostatic pressing process using chemical vapor deposition, wherein the canister has a profile corresponding to a profile of the mandrel, and removing the mandrel from the canister.12. A method according to claim 11, wherein the mandrel is coated with a coating material comprising any of tantalum or niobium or an alloy thereof.13. A method of manufacturing a part using a hot isostatic pressing process, the method comprising: providing a canister according to any of the preceding claims; filling the canister with powder; consolidating the powder to form a part, and; removing the canister from the part.14. A method according to claim 13, wherein, prior to filling with powder, a release agent is applied to the inside of the canister.15. A method according to claim 13 or 14 comprising the step of checking the canister for vacuum tightness using a helium leak detector.16. A method according to any of claims 13 to 15, wherein air is vacated from the filled canister using a vacuum pump.17. A method according to claim 16, when dependent on claim 10, comprising crimping and heating the one or more tubes to maintain a vacuum in the canister.18. A method according to claim 17, comprising partially filling the one or more tubes with a chemically reactive getter material for maintaining the vacuum.19. A method according to any of claims 13 to 18, wherein removing the canister comprises machining the canister off the part.20. A method of processing a design drawing of a finished part, the method comprising: from a design drawing of a finished part having a surface area, extracting the surface area from the design drawing; increasing the surface area of the finished part between 5% and 10%; creating an amended design drawing of an initial part having the increased surface area, and; outputting the amended design drawing for manufacturing the finished part according to a manufacturing process.21. A method according to claim 20, wherein creating the amended design comprises introducing a hollow core in the initial part.22. A method according to claim 20 or claim 21, wherein creating the amended design comprises introducing a reinforcing element in the initial part.23. A method according to any of claims 20 to 22, wherein creating the amended design comprises introducing a fixture into the initial part for holding the anode relative to the initial part.24. A method according to any of claims 20 to 23, wherein increasing the surface area comprises increasing a dimension of the finished part by between 5% and 10%.25. A method according to any of claims 20 to 24, wherein the manufacturing process is an additive manufacturing process.