GB2597240A

GB2597240A - Improved method of solvent recovery

Info

Publication number: GB2597240A
Application number: GB2010336.2A
Authority: GB
Inventors: Crabtree Joseph; Rybalcenko Konstantin; Gaio Andre; Folgar Luis; Pap-Kovács Viktor
Original assignee: Additive Manufacturing Technologies Ltd
Current assignee: Additive Manufacturing Technologies Ltd
Priority date: 2020-07-06
Filing date: 2020-07-06
Publication date: 2022-01-26
Anticipated expiration: 2040-07-06
Also published as: GB202010336D0; GB2597240B

Abstract

A method of post-processing an additively manufactured part comprises locating an additively manufactured part 10 in a processing chamber 100, introducing a solvent vapour into said processing chamber, processing a surface of the additively manufactured part located therein, adjusting a pressure and/or a temperature within the processing chamber so as to cause the solvent present within the processing chamber to condense and then extracting the condensed solvent from the processing chamber. The condensing step may include introducing a gas into the processing chamber so as to increase the pressure therein. The recovery step may include collecting the condensed solvent in a solvent reservoir or cartridge 114, which may be removable from the processing chamber. The reservoir may include first compartment 114a for virgin solvent and a second compartment 114b for recovered solvent. A negative pressure may be applied to the chamber. Chambers are also provided with a drain 112 and hydrophobic coating and/or texture surface.

Description

IMPROVED METHOD OF SOLVENT RECOVERY

FIELD

The present disclosure relates to a method of processing an additively manufactured part and a processing chamber for performing the same.

BACKGROUND

Following the increased popularity of additive layer manufacturing in recent years, there has also been significant innovations in post-processing methodologies for improving the surface finish of additively manufactured parts.

Additively manufactured parts typically exhibit a rough and castellated outer surface which can be caused by the presence of un-sintered or partially sintered build powder on the surface of the part, as well as the layer-by-layer build process typically associated with additively manufacturing methodologies.

One known method for post-processing such parts is described in GB2560073A, wherein the surface of an additively manufactured part is processed using a solvent vapour which is controllably introduced into a processing chamber.

Once the additively manufactured part has been processed, the solvent vapour is extracted from the processing chamber via a vacuum pump. The solvent vapour is then passed through a condenser to enable the solvent present in the vapour to be condensed and returned to a solvent reservoir so as to reduce wastage.

However, known condenser units tend to be heavy and large in size since they require a large contact surface which must be adequately cooled to enable the solvent present in the vapour to be condensed. This makes installation of such systems difficult in practice.

Furthermore, condenser units tend to have an ideal flow capacity in the region of 150L per hour, whereas the amount of solvent present in a solvent vapour used for post-processing additively manufactured parts tends to be in the region of 300g, which is significantly less than the capacity of the condenser. Such units also require a significant amount of energy to obtain the desired cooling effects. As such, the use of known condensers for the recovery of solvent present in a solvent vapour tends to be inefficient.

In addition, the use of separate systems for processing the additively manufactured part and for solvent recovery makes automating this process more difficult.

It is therefore the aim of the present disclosure to address at least one of these aforementioned problems encountered when using known solvent recovery systems.

SUMMARY

According to a first aspect of the disclosure, there is provided a method of post-processing an additively manufactured part, the method comprising locating an additively manufactured part in a processing chamber, introducing a solvent vapour into said processing chamber, performing a processing step, wherein the solvent vapour introduced into the processing chamber is used to process a surface of the additively manufactured part located therein, performing a condensing step, wherein, after the processing step, a pressure and/or temperature within the processing chamber is adjusted so as to cause the solvent present within the processing chamber to condense and performing a recovery step, wherein the solvent condensed during the condensing step is extracted from the processing chamber.

Advantageously, since the aforementioned method allows all of the processing, condensing and solvent recovery operations to be performed within the processing chamber, it is possible to perform the aforementioned method as a single, automated process, thereby helping to improve operational efficiency.

Furthermore, it has been found that by condensing the solvent vapour within the processing chamber for extraction, the need for expensive and inefficient condenser units can be avoided.

Furthermore, it has also been found that condensing the solvent vapour within the processing chamber (rather than via a condenser) can help to improve the purity of the condensed, recovered solvent.

In exemplary embodiments, the condensing step comprises cooling an interior of the processing chamber.

In exemplary embodiments, the condensing step comprises cooling an interior of the processing chamber to a temperature in the range of 10°C to 40°C.

Advantageously, cooling the interior of the processing chamber provides an effective method for condensing the solvent vapour.

Furthermore, cooling the interior of the processing chamber also helps to prevent re-evaporation of any condensed solvent within the processing chamber.

In exemplary embodiments, the condensing step comprises introducing a gas into the processing chamber so as to increase the pressure therein.

In exemplary embodiments, the condensing step comprises introducing a gas into the processing chamber so as to increase the pressure therein to a pressure of at least 400 m Bar.

Advantageously, increasing the pressure within the processing chamber provides an effective method for condensing the solvent vapour.

In exemplary embodiments, the gas introduced into the processing chamber during the condensing step is cooled prior to being introduced into the processing chamber.

In exemplary embodiments, the gas introduced into the processing chamber during the condensing step is cooled to a temperature in the range of 10°C to 40°C prior to being introduced into the processing chamber.

Advantageously, increasing the pressure of the processing chamber with a cool gas enables the pressure and temperature conditions within the chamber to be simultaneously adjusted to cause condensation of the solvent vapour, thereby improving operational efficiency.

In exemplary embodiments, the gas introduced into the processing chamber is directed towards an interior surface of the processing chamber so as to promote condensation of the solvent onto said interior surface of the processing chamber.

Advantageously, directing the gas towards an interior surface of the processing chamber has been found to help promote condensation of the solvent onto said surface.

In exemplary embodiments, the solvent vapour comprises a first solvent and a second solvent, the condensing step comprises adjusting the pressure and/or temperature within the processing chamber so as to cause the first solvent to condense whilst the second solvent remains in vapour form, and the recovery step comprises extracting the first, condensed solvent from the processing chamber.

Advantageously, it has been found that by iteratively condensing and recovering the solvent mixture, the purity of the each of the recovered solvents is improved without the need for any additional processes.

In exemplary embodiments, the recovery step comprises collecting the condensed solvent in a solvent reservoir.

In exemplary embodiments, the recovery step comprises returning the condensed solvent to a solvent reservoir.

Advantageously, returning the condensed solvent to the reservoir enables the recovered solvent to be re-cycled thereby reducing solvent wastage.

In exemplary embodiments, the solvent reservoir is removable from the processing chamber.

In exemplary embodiments, the solvent reservoir is a solvent cartridge.

In exemplary embodiments, the solvent reservoir comprises a first compartment for virgin solvent and a second compartment for recovered solvent, and the recovery step comprises returning the condensed solvent to the second compartment of the solvent reservoir.

Advantageously, providing separate compartments for the recovered and virgin solvents enables the purity of the solvent applied to the additively manufactured part to be better controlled, and hence more effective processing can be achieved as a result.

In exemplary embodiments, the method further comprises a heating step, performed prior to the processing step, wherein the solvent is heated so as to cause the solvent to vaporise prior to the solvent being introduced into the processing chamber.

Advantageously, heating the solvent prior to introduction into the processing chamber helps to minimise heating of the processing chamber. Consequently, heating of the part can be better avoid which helps to prevent damage to the part and also helps to improve condensation of the solvent vapour onto the part during processing.

In exemplary embodiments, the processing step comprises applying a negative pressure to an interior of the processing chamber.

In exemplary embodiments, the method further comprises, prior to the condensing step, applying a hydrophobic coating to an interior surface of the processing chamber.

In exemplary embodiments, the hydrophobic coating has a surface energy less than 40 mN/m.

In exemplary embodiments, the hydrophobic coating has a surface energy less than mN/m.

Advantageously, the application of a hydrophobic coating helps to prevent wetting of the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the method further comprises, prior to the condensing step, applying a hydrophobic texture to an interior surface of the processing chamber.

Advantageously, the application of a hydrophobic texture helps to prevent wetting of the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the hydrophobic texture is selected or arranged such that, in use, the contact angle formed between the interior surface on which the hydrophobic texture has been applied and the solvent condensed onto said interior surface is greater than 1200.

In exemplary embodiments, the hydrophobic texture is selected or arranged such that, in use, the contact angle formed between the interior surface on which the hydrophobic texture has been applied and the solvent condensed onto said interior surface is greater than 150°.

Advantageously, the hydrophobic texture helps to further prevent wetting of the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the hydrophobic texture is applied via laser surface texturing.

Advantageously, laser surface texturing provides an efficient and effective method of applying a hydrophobic texture to an interior surface of the processing chamber.

Furthermore, laser surface texturing enables a hydrophobic texture and an increased carbon content to be simultaneously applied to an interior surface of the processing chamber, thereby further improving manufacturing efficiency.

In exemplary embodiments, the processing chamber comprises an interior surface made of a material having a carbon content, and the method further comprises processing the interior surface of the processing chamber so as to increase the carbon content of said material.

Advantageously, since carbon-carbon bonds have a low surface energy, increasing the carbon content of the interior surface helps to prevent wetting of the walls of the processing chamber.

According to a second aspect of the present disclosure, there is provided a processing chamber for processing an additively manufactured part, the processing chamber comprising an interior cavity for receiving an additively manufactured part, a solvent inlet for introducing a solvent into said interior cavity, a condensing mechanism for adjusting a pressure and/or a temperature within the interior cavity so as to cause the solvent present within the interior cavity to condense and a drain for extracting the condensed solvent from the interior cavity of the processing chamber.

Advantageously, it has been found that by providing a processing chamber having a condensing mechanism and a drain which enables the solvent to be condensed for extraction, the need for expensive and inefficient condenser units can be avoided.

In exemplary embodiments, the condensing mechanism comprises a cooler.

In exemplary embodiments, the cooler is arranged so as to cool a surface of the interior cavity of the processing chamber.

In exemplary embodiments, the cooler is arranged so as to cool a base of the interior cavity of the processing chamber.

Advantageously, the feature of a cooler provides an effective mechanism for causing the solvent present within the processing chamber to condense onto a desired surface of the chamber (e.g. the base).

Furthermore, providing a cooler at the base helps to localise the condensed solvent proximal to the drain which helps the condensed solvent to be more efficiently extracted.

In addition, the feature of a cooler also provides an effective mechanism for helping to prevent any condensed solvent within the chamber from re-evaporating.

S

In exemplary embodiments, the condensing mechanism comprises a gas inlet for introducing a gas into the interior cavity of the processing chamber so as to increase the pressure therein.

In exemplary embodiments, the gas inlet is arranged so as to direct a flow of gas towards a surface of the interior cavity so as to promote condensation of the solvent onto said surface of the interior cavity.

Advantageously, the feature of a gas inlet which allows the pressure within the chamber to be increased helps to further adjust the thermodynamic conditions within the chamber to promote condensation, thereby helping to more efficiently condense the solvent vapour located within the chamber.

Furthermore, arranging the gas inlet so as to direct a flow of gas towards an interior surface of the processing chamber has been found to promote condensation of the solvent onto said surface.

In exemplary embodiments, a cooler is located at, or upstream of, the gas inlet so as to cool the gas prior to introduction into the interior cavity of the processing chamber.

Advantageously, locating the cooler at or upstream of the gas inlet enables the processing chamber to be simultaneously cooled and pressured via the flow of gas introduced into the chamber via the gas inlet, thereby helping to more efficiently condense the solvent vapour located therein.

In exemplary embodiments, the interior cavity is arranged so as to cause the condensed solvent to flow towards the drain.

In exemplary embodiments, the interior cavity comprises a base, the drain is located at the base of the interior cavity, and the base is angled so as to cause condensed solvent present on the base to flow towards the drain.

Advantageously, the angled base helps to guide the condensed solvent towards the drain thereby helping the condensed solvent to be more efficiently recovered.

In exemplary embodiments, the interior cavity comprises a surface having a coating having a surface energy less than or equal to 60 mN/m.

In exemplary embodiments, the interior cavity comprises a surface having a coating having a surface energy less than or equal to 40 mN/m.

In exemplary embodiments, the interior cavity comprises a surface having a coating having a surface energy less than or equal to 20 mN/m.

Advantageously, the hydrophobic coating helps to prevent condensed solvent from "sticking" to the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the interior cavity comprises a base, and wherein the surface of said base comprises said coating.

In exemplary embodiments, the interior cavity comprises a surface having a texture selected or arranged such that, in use, the contact angle formed between the surface on which the texture has been applied and the solvent condensed onto said surface is greater than 900.

In exemplary embodiments, the interior cavity comprises a surface having a texture selected or arranged such that, in use, the contact angle formed between the surface on which the texture has been applied and the solvent condensed onto said surface is greater than 1200.

In exemplary embodiments, the interior cavity comprises a surface having a texture selected or arranged such that, in use, the contact angle formed between the surface on which the texture has been applied and the solvent condensed onto said surface is greater than 1500.

Advantageously, the application of a hydrophobic texture helps to prevent condensed solvent from "sticking" to the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the interior cavity comprises a base, the surface of said base comprises said texture.

In exemplary embodiments, the interior cavity comprises a surface comprising an array of protrusions.

Advantageously, providing an array of protrusions on the interior surface(s) of the processing chamber helps to increase the contact angle formed between the surface and the condensed solvent, thereby helping to further prevent wetting of the processing chamber.

In exemplary embodiments, the interior cavity comprises a surface comprising an array of nodules, wherein each nodule has a diameter in the range of 1 micron to 1000 microns.

Advantageously, providing an array of nodules on the interior surface(s) of the processing chamber helps to further increase the contact angle formed between the surface and the condensed solvent, thereby helping to further prevent wetting of the processing chamber.

In exemplary embodiments, the spacing between each nodule of the array of nodules is in the range of 10 microns to 10,000 microns.

In exemplary embodiments, the interior cavity comprises a base, the base comprising a surface defining a surface of the interior cavity and a main body, the surface and the main body each comprise a material, and the material of the surface has a carbon content which is greater than the carbon content of the material of the main body.

In exemplary embodiments, the interior cavity comprises at least one sidewall, the at least one sidewall comprising a surface defining a surface of the interior cavity and a main body, the surface and the main body each comprise a material, and the material of the surface has a carbon content which is greater than the carbon content of the material of the main body.

In exemplary embodiments, the interior cavity comprises a base and at least one sidewall, the base and/or the at least one sidewall each comprise a surface defining the surface of the interior cavity and a main body, the surface and the main body each comprise a material, and wherein the material of the surface has a carbon content which is greater than the carbon content of the material of the main body. Advantageously, since carbon-carbon bonds have a low surface energy, increasing the carbon content of the surface of the base and/or at least one sidewall helps to prevent wetting of the walls of the processing chamber, thereby helping to further prevent condensed solvent from "sticking" to the interior walls of the chamber.

According to a third aspect of the present disclosure, there is provided a processing chamber for processing an additively manufactured part, the processing chamber comprising an interior cavity for receiving an additively manufactured part, the interior cavity comprising a surface, a solvent inlet for introducing a solvent into said interior cavity and a condensing mechanism for adjusting a pressure and/or a temperature within the interior cavity so as to cause the solvent present within the interior cavity to condense, wherein the surface of the interior cavity comprises a hydrophobic coating and/ or a hydrophobic texture.

Advantageously, providing a processing chamber having a hydrophobic coating or texture helps to prevent condensed solvent from "sticking" to the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the surface of the interior cavity comprises a hydrophobic coating.

In exemplary embodiments, the hydrophobic coating has a surface energy less than or equal to 40 mN/m.

In exemplary embodiments, the hydrophobic coating has a surface energy less than or equal to 20 mN/m, Advantageously, the hydrophobic coating helps to prevent condensed solvent from "sticking" to the interior walls of the chamber thereby helping condensed solvent to be recovered more efficiently.

In exemplary embodiments, the surface of the interior cavity comprises a hydrophobic texture.

In exemplary embodiments, the hydrophobic texture is selected or arranged such that, in use, the contact angle formed between the surface on which the hydrophobic texture has been applied and the solvent condensed onto said surface is greater than 1200.

In exemplary embodiments, the hydrophobic texture is selected or arranged such that, in use, the contact angle formed between the surface on which the hydrophobic texture has been applied and the solvent condensed onto said surface is greater than 150°.

In exemplary embodiments, the hydrophobic texture comprises an array of protrusions.

In exemplary embodiments, the hydrophobic texture comprises an array of nodules, wherein each nodule has a diameter in the range of 1 micron to 1000 microns.

In exemplary embodiments, the interior cavity comprises a base and at least one sidewall, the base and/or the at least one sidewall each comprise a surface defining the surface of the interior cavity and a main body, the surface and the main body each comprise a material, and wherein the material of the surface has a carbon content which is greater than the carbon content of the material of the main body.

Advantageously, since carbon-carbon bonds have a low surface energy, increasing the carbon content of the surface of the base and/or at least one sidewall helps to prevent wetting of the walls of the processing chamber, thereby helping to further prevent condensed solvent from "sticking" to the interior walls of the chamber.

In exemplary embodiments, the condensing mechanism comprises a cooler.

In exemplary embodiments, the cooler is arranged so as to cool the surface of the interior cavity of the processing chamber.

Advantageously, the feature of a cooler provides an effective mechanism for causing the solvent present within the processing chamber to condense.

In exemplary embodiments, the gas inlet is arranged so as to direct a flow of gas towards the surface of the interior cavity so as to promote condensation of the solvent onto said surface of the interior cavity.

In exemplary embodiments, the processing chamber comprises a base, and the interior cavity of the processing chamber is arranged so as to cause the condensed solvent to flow towards the base of the processing chamber.

In exemplary embodiments, the processing chamber further comprises a drain for extracting the condensed solvent from the interior cavity of the processing chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a processing chamber according an embodiment

of the present disclosure;

Figure 2A is a schematic illustration of a hydrophobic surface suitable for use with the processing chamber illustrated in Figure 1; Figure 2B is a schematic illustration of another hydrophobic surface suitable for use with the processing chamber illustrated in Figure 1; Figure 2C is a schematic plan view of the hydrophobic surface illustrated in Figure 2B; Figure 2D is a schematic illustration of yet a further hydrophobic surface suitable for use with the processing chamber illustrated in Figure 1; Figure 2E is a schematic illustration of another hydrophobic surface suitable for use with the processing chamber illustrated in Figure 1; Figure 3 is a schematic illustration of a processing chamber according to an alternative

embodiment of the present disclosure;

Figure 4 is a flow chart illustrating a method of processing an additively manufactured part according to an embodiment of the present disclosure; and Figure 5 is a line graph illustrating the optimal temperature and pressure conditions for vaporising and condensing an HFIP solvent.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Figure 1 shows a processing chamber 100 for an additively manufactured part according to an embodiment of the present disclosure.

The processing chamber 100 is made up of a base 102 and a plurality of sidewalls 104a, 104b, the interior surfaces of which define an interior cavity 106 within the processing chamber 100.

The interior cavity 106 is of a size suitable for receiving at least one additively manufactured part 10 for processing (the method of which shall be described in greater detail at a later stage within this application).

In the embodiment illustrated in Figure 1, the additively manufactured part 10 is supported on a supporting mesh 105 which enables passage of the condensed solvent through the mesh 105 for collection and recovery (as shall be described in greater detail below). In the illustrated embodiment, the supporting mesh is provided in the form of a mesh plate. However, it shall be appreciated that other suitable mesh configurations may alternatively be used. It shall also be appreciated that, in other embodiments, the processing chamber may include a plurality of supporting meshes to enable multiple parts to be processed within the chamber at any one time.

It shall also be appreciated that in some embodiments, other such supporting mechanisms may be used. For example, in some embodiments, the additively manufactured part or parts may be suspended from a roof of the processing chamber for processing.

The interior cavity 106 of the processing chamber 100 is in fluid communication with a solvent inlet 107 configured for introducing a solvent vapour into the interior cavity 106 of the processing chamber 100 so as to create a vapour saturated environment within the interior cavity 106 of the processing chamber 100 as is required during certain processing stages (as shall be described in greater detail at a later stage of the application)..

The processing chamber 100 also has a heating arrangement configured to control a temperature of the interior cavity 106 of the processing chamber 100 so as to obtain optimal thermodynamic processing conditions required for processing the additively manufactured part 10 at each of the respective processing stages (as shall be described in greater detail at a later stage of the application).

In the illustrated embodiment, the heating arrangement is provided as a pair of heating elements 108a, 108b configured for heating the respective sidewalls 104a, 104b of the processing chamber 100. Advantageously, the provision of a pair of heating elements 108a, 108b located on each sidewall 104a, 104b helps to prevent any unwanted condensation of solvent onto the sidewalls of the processing chamber during processing of the additively manufactured part 10. However, it shall be appreciated that in other embodiments, a different number of heating elements (such as one, three, four etc.) may be provided and said heating elements may be located at different location on said processing chamber, such as at the base of the processing chamber.

The processing chamber 100 also has an additional heating element 108c, located upstream of the solvent inlet 107, configured for heating the solvent so as to cause it to vaporise prior to introduction into the interior cavity 106 of the processing chamber 100. However, in other embodiments, the solvent may be pre-vaporised and so this heating element may be omitted in some embodiments.

The processing chamber 100 also features a condensation mechanism for controlling the thermodynamic conditions within the processing chamber during each step of the process. The condensation mechanism is made up of a pressure controlling arrangement 109 and a cooling mechanism. The pressure controlling arrangement 109 is configured for controlling the pressure of the interior cavity 106 of the processing chamber 100 and the cooling mechanism is configured for controlling the temperature of the interior cavity 106 of the processing chamber 100.

In the illustrated embodiment, the pressure controlling arrangement 109 is made up of a vacuum pump 109a and an outlet 109b configured to permit egress of gas from within the interior cavity 106 of the processing chamber 100 to a location external to the interior cavity 106 of the processing chamber 100, such as the atmosphere. The interior cavity 106 is vacuum-tight and sealable. As such, the ejection of gas from the interior cavity 106 enables the pressure within the processing chamber 100 to be controllably decreased via the vacuum pump 109a.

In addition, the pressure controlling arrangement 109 also includes a gas inlet 109c and a valve 109d. The valve 109d is located in line with the gas inlet 109c such that when the valve 109d is opened, ambient air is allowed to flow through the gas inlet 109c and into the interior cavity 106 of the processing chamber, and when the valve 109d is closed, ambient air is not allowed to flow through the gas inlet 109c and into the interior cavity 106 of the processing chamber. In this way, the pressure within the interior cavity 106 can be controllably increased via opening the valve 109d.

During operation, the pressure controlling arrangement 109 is used to raise and lower the pressure of the processing chamber to enable the system 100 to obtain optimal thermodynamic processing conditions for each of the respective processing steps, as shall be described in later parts of this application.

Meanwhile, the cooling mechanism is configured for selectively cooling the interior cavity 106 of the chamber 100 so as to provide favourable conditions for the solvent to condense and to prevent re-evaporation of already condensed solvent within the chamber 100 during the condensation and recovery steps of the method.

In the illustrated embodiment, the cooling mechanism is provided in the form of a pair of coolers 110a, 110b located at the base 102 of the processing chamber 100 configured for cooling the base 102 of the processing chamber 100 so as to promote condensation of the solvent located within the interior cavity 106 onto the surface of the base 102. However, it shall be appreciated that in other embodiments, a different number of coolers (such as one, three, four etc.) may be provided configured for cooling a different surface of the interior cavity 106 of the processing chamber 100 instead of, or in addition to, the base 102, such as the interior surface of the sidewalls 104a, 104b.

The processing chamber 100 also features a drain 112, also located at the base 102, which provides an outlet from the processing chamber 100 for extracting the condensed solvent from the interior cavity 106 of the processing chamber 100. The base 102 of the processing chamber 100 is further configured to enable condensed solvent to flow from the surfaces of the sidewalls 104a, 104b and base 102 into the drain 112 to allow for more effective recovery of the condensed solvent.

In the embodiment illustrated in Figure 1, the base 102 of the processing chamber 100 has a pair of angled surfaces 102a, 102b forming a V-shape in cross section so as to funnel any condensed solvent that flows onto the base towards. However, it shall be appreciated that other suitable configurations for guiding condensed solvent to the drain may be provided. Furthermore, although not shown in the illustrated embodiment, in some embodiments, the sidewalls of the processing chamber may also be angled so as to help further guide condensed solvent towards the drain 112.

In the illustrated embodiment, the drain 112 is provided as a vacuum or suction drain, similar to that which would be found in an aircraft or locomotive toilet, which helps to recover condensed solvent more efficiently. However, it shall be appreciated that in other embodiments, other suitable mechanisms for extracting condensed solvent from the chamber may be used.

The drain 112 is provided in fluid communication with a solvent reservoir 114 so that the condensed solvent recovered via the drain 112 can be recycled and returned to the solvent reservoir 114 where it can be used for future processes, thereby helping to reduce solvent wastage. However, in alternative embodiments, the processing chamber may instead be configured to collect the condensed solvent in a sump, and hence it shall be appreciated that in such embodiments, the drain may be omitted.

The solvent reservoir 114 according to the illustrated embodiment is provided in the form of a removable solvent cartridge which is releasably coupled to the processing chamber 100 to facilitate easy removal and replacement during processing, for example when the solvent levels within the cartridge are low or when a different solvent type is required.

The solvent reservoir 114 includes a first compartment 114a for virgin solvent and a second compartment 114b for recovered solvent, the drain 112 being in fluid communication with the second compartment 114b of the solvent reservoir 114.

However, it shall be appreciated that in other embodiments, the solvent reservoir may only feature a single compartment, or in further embodiments, the drain may not be in fluid communication with the fluid reservoir, with the recovered solvent instead being discarded as waste.

The solvent reservoir 114 is also in fluid communication with the solvent inlet 107 of the processing chamber 100 such that solvent from the solvent reservoir 114 can be introduced into the interior cavity 106 of the processing chamber 100 to enable the additively manufactured part 10 (or parts) located therein to be processed as shall be described at a later stage of the present application.

The base 102 and sidewalls 104a, 104b of the processing chamber 100 are typically formed from metallic materials. For example, in the illustrated embodiment, the base 102 and sidewalls 104a, 104b are made from a stainless steel. However, to help improve solvent recovery, the base 102 and/or sidewalls 104a, 104b of the processing chamber 100 are also applied with a hydrophobic coating and/or texture to help prevent condensed solvent from "sticking" to the surfaces of the interior cavity 106, thereby helping the condensed solvent to be recovered more efficiently.

A hydrophobic coating according to one embodiment of the present disclosure, which is suitable for use with the processing chamber 100 illustrated in Figure 1, is illustrated in Figure 2A.

As can be seen in Figure 2A, the base 202 according to this embodiment of the present disclosure features a main body 204 and a surface 206 which defines a surface of the interior cavity 106 of the processing chamber 100 when in use.

The main body 204 is made from a metallic material, such as stainless steel, to which a hydrophobic coating is applied, said hydrophobic coating forming the surface 206 of the base 202.

It is important to note that whilst the illustrated embodiment is described in relation to a base of the processing chamber, in other embodiments, hydrophobic coatings may be applied to other surfaces of the interior cavity such as the sidewalls and even a roof of the interior cavity 106.

According to the present disclosure, the term "hydrophobic coating" is defined as a coating having a surface energy less than or equal to 60 mN/m. In the embodiment illustrated in Figure 2A, the hydrophobic coating is provided as a Polytetrafluoroethylene (PTFE) coating with surface energy of 18 mN/m. However, in other embodiments, other suitable hydrophobic materials such as polyethylene (PE) or polypropylene (PP) may be used.

The "wettability" of a material defines the ability of a liquid to maintain contact with the surface of said material. In the case of the present disclosure, so called "wetting" of the surfaces of the interior cavity 106 is undesirable since this prevents the condensed solvent from flowing from the surfaces on which the solvent has condensed towards the drain 112 for recovery. As such, surfaces having a low wettability are desirable as they help the condensed solvent to be recovered more efficiently.

Wetting (S) can be quantified using the equation below, wherein Ys is the surface energy of the material, YI is the surface energy of the liquid and Ys-I is the surface energy of the interface between the material and the liquid.

S = Ys --Ys-As such, materials having a low surface energy (e.g. below 60 mN1m) are typically more difficult to wet and can therefore help to prevent the condensed solvent from "sticking" to the surfaces of the interior cavity.

In order to prevent wetting, the value of "S" must be less than zero. However, some solvents, such as 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP), exhibit a very low surface energy (Y1). For example, the surface energy (Y0 of HFIP is 16.1 mN/m. As such, for some solvents (such as HFIP), additional features may be required to help further promote efficient recovery of condensed solvent from within the interior cavity of the processing chamber instead of, or in addition to, a hydrophobic coating.

One such example of an alternative feature which can be used to help promote efficient recovery of condensed solvent from within the interior cavity 106 of the processing chamber 100 is illustrated in Figures 2B and 2C.

As shown in Figure 2B, the base 302 according to this embodiment of the present disclosure features a hydrophobic texture in order to help prevent wetting of the material which makes up the base 302.

The surface 306 of the base 302 features an array of protruding nodules 310a-I. In the illustrated embodiment, the array of nodules 310a-I are provided having a diameter (D) of approximately 500 microns with each nodule being spaced by a distance (S) of between 500 and 1500 microns apart. However, it shall be appreciated that in other embodiments, protrusions having other suitable diameters and spacings may be used. For example, in an alternative embodiment, an array of micro-modules having a diameter of 12.5 microns and a spacing of 25 microns is provided.

When a liquid is applied to a perfectly smooth surface, the liquid is able to spread out and flow, forming a thin uniform film of liquid across the surface. In this configuration, the contact angle (i.e. the angle formed where the liquid interface meets the solid surface) is considered to be 0°. Since the thin, uniform film of liquid is able to maximise the surface area of the liquid, the liquid is able to form stronger intermolecular bonds with the material of the surface and hence a greater degree of wetting is observed. In fact, a contact angle of 0° is considered to be ideal wetting conditions.

This is undesirable in the case of the present disclosure since wetting of the surfaces of the interior cavity 106 makes it more difficult to efficiently recover condensed solvent.

Advantageously, it has been found that the application of an array of protrusions, which increase the roughness of the surface to which they are applied, are beneficial in reducing the wettability of the surface. Notably, the interfaces where a liquid meets a solid surface on rough surfaces tend to be pinned at angles which are not completely flat due to the undulating nature of rough surfaces.

As such, the contact angle formed where the liquid interface meets the solid surface on rough surfaces tends to be greater than 0°, thereby helping to prevent wetting of the surface.

According to the present disclosure, the term "hydrophobic texture" is defined as a coating having a contact angle in the range of 90° to 1800 (N.B. a contact angle of 1800 is considered to be perfectly non-wetting).

In the illustrated embodiments, the array of nodules 310a-I are applied via laser surface texturing. Using this method, it has been found that surfaces featuring contact angles as high as 1540 can be obtained, which further helps to prevent wetting of the surfaces of the processing chamber 100. However, in alternative embodiments, it shall be appreciated that other suitable methods may be used.

Furthermore, laser surface texturing also has the further advance of increasing the carbon concentration of the surface of the material to be processed. For example, stainless steels suitable for use in the processing chamber 100 typically exhibit a carbon concentration of approximately 10%. However, during laser treatment, it has been observed that the carbon dioxide present in the laser source tends to dissociate into carbon during processing, which leads to increased carbon deposits on the surface of the processed material. In fact, the surface of the stainless steel samples processed via laser surface texturing have been found to exhibit carbon concentrations of up to 30%.

Advantageously, since amorphous carbon-carbon bonds have a much lower surface energy than that of steel, increasing the carbon content of the surface helps to further decrease the wettability of the surface.

However, whilst in the present embodiment the carbon content of the material of the processing chamber 100 is increased via laser surface texturing, it shall be appreciated that, in other embodiments, other suitable methods for increasing the carbon content of the material may be used.

According to embodiments of the present disclosure, it shall also be appreciated that different forms of protrusion (other than nodules) can be used in order to obtain a surface having a hydrophobic texture.

One such example of an alternative form of protrusion which can be used to help promote efficient recovery of condensed solvent from within the interior cavity 106 of the processing chamber 100 is illustrated in Figure 2D.

As shown in Figure 2D, the array of protrusions may be an array of asymmetric protrusions (410). The asymmetric protrusions 410 in this example have an isosceles triangular shape in cross section, similar to the spines of a cactus plant, extending from an apex 412 down to a protrusion base 414.

Furthermore, it shall also be appreciated that the examples described in Figures 2A to 2D can be combined as shown in Figure 2E.

In the embodiment illustrated in Figure 2E, a base 502 having a hydrophobic coating and a hydrophobic texture is provided. The hydrophobic coating is provided as an HFIP coating provided on a surface 506 of the base 502, similar to that described in Figure 2A. However, it shall be appreciated that other suitable coatings, such as PE and PP coatings may be used.

Furthermore, the hydrophobic texture is provided in the form of an array of protrusions 510 having an asymmetric cross-sectional shape. However, unlike the protrusions illustrated in Figure 2D, the protrusions 510 also exhibit a part spherical profile, similar to the nodules illustrated in Figures 2B and 20.

Advantageously, by combining the concepts illustrated in Figures 2A to 2D, it has been found that the wettability of the surfaces of the interior cavity 106 can be further reduced.

Meanwhile, a processing chamber 600 for an additively manufactured part according to an alternative embodiment of the present disclosure is shown in Figure 3.

The processing chamber 600 illustrated in Figure 3 has many features in common with the processing chamber 100 described with reference to Figure 1. Therefore, for the sake of conciseness, only the differences shall be described below. Furthermore, common parts have been designated with corresponding reference numerals having the prefix "6".

Notably, in the processing chamber 600 illustrated in Figure 3, the condensation mechanism is provided in the form of a pair of inlets 620, 630 configured to introduce a flow of gas into the interior cavity 606 of the processing chamber 600.

In the embodiment illustrated in Figure 3, the gas introduced into the interior chamber is a flow of nitrogen gas. However, it shall be appreciated that in other embodiments, other gases may be used. For example, in some embodiments, the gas may be ambient air.

As the gas is introduced into the interior cavity 606 of the processing chamber 600, the pressure within the interior cavity 606 is subsequently increased. It has been found that at increased pressures, vaporised solvents tend to condense more readily, even at ambient temperatures.

As such, the introduction of gas into the interior cavity 606 of the processing chamber 600 so as to increase the pressure therein has the effect of promoting condensation of the solvent within the interior cavity 606.

Furthermore, the inlets 620 and 630 are also arranged such that the flow of gas introduced into the interior cavity 606 of the processing chamber 600 is directed towards the respective sidewalls 604a, 604b which form the interior cavity 606 of the processing chamber 600, although it shall be appreciated that in other embodiments the inlets 620, 630 may direct the flow of gas towards the base 602.

Advantageously, it has been found that arranging the inlets 620, 630 so as to direct a flow of gas towards a surface of the interior cavity 606 helps to direct the solvent vapour located therein onto said surfaces which, as a consequence, helps to promote condensation of the solvent onto the surfaces of the processing chamber 600.

The processing chamber 600 also has a pair of coolers 610a, 610b located upstream of the respective the inlets 620, 630 so as to cool the gas prior to introduction into the interior cavity 606 of the processing chamber 600.

This enables the pressure of the interior cavity 606 to be increased whilst the temperature of the interior cavity 606 is simultaneously cooled. As such, this helps the system to more efficiently achieve optimal thermodynamic conditions for promoting condensation of the solvent located within the interior cavity 606. However, it shall be appreciated that in some embodiment, the coolers may be omitted.

Furthermore, whilst in the embodiment illustrated in Figure 3 the condensation mechanism is provided as a pair of inlets 620, 630, it shall be appreciated that in other embodiments, a different number of inlets (and optionally corresponding coolers), such as one, three, four etc., may be provided.

In addition, it shall also be appreciated that features of the embodiments illustrated in Figures 1 and 3 may be combined.

A method for processing an additively manufactured part using the afore-described processing chambers shall now be described with reference to Figure 4.

As a first step 701 in the method, an additively manufactured part 10 is loaded into the interior cavity 106 of the processing chamber 100 and placed on the supporting mesh ready for processing.

A chemical solvent such as an acid, an ionic liquid or another component suitable for transforming the additively manufactured part 10 is then introduced into the processing chamber 100 via the solvent inlet 107 at step 702.

The chemical solvent is supplied via the solvent reservoir 114 in a liquid form and is heated via the heating element 108c so as to cause the solvent to vaporise prior to being introduced into the processing chamber 100.

This is advantageous since it reduces the amount of heating that is required within the processing chamber 100, which in turn can help to reduce any damage being caused to the additively manufactured part 10 due to excessive heating.

Examples of suitable chemical solvents include, but are not limited to 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), dichloromethane (DCM), dichloroethane, dimethylformamide (DMF), formic acid, chloroform and acetic acid.

In the illustrated embodiment, an HEIR solvent is used. However, it shall be appreciated that in other embodiments, other suitable solvents may be used.

The amount of solvent introduced into the processing chamber 100 is controlled based upon the surface area and the number of parts to be processed during the process.

During introduction of the solvent into the processing chamber 100, the processing chamber 100 is also maintained at a negative pressure, typically in the range of 0 mBar and 400 mBar. It has been found that solvents such as HFIP tend to vaporise more easily at lower pressures. As such, maintaining the processing chamber 100 at a negative pressure at this stage helps to keep the solvent in a gaseous state as it is introduced into the interior cavity 106 without having to increase the temperature within the chamber 100 (which could risk damaging the part 10).

Once the chemical vapour has been introduced into the processing chamber, the heating elements 108a, 108b and the pressure controlling arrangement 109 are controlled to maintain the interior cavity 106 of the processing chamber 100 at a temperature between 10°C and 40°C and at a pressure between 200-1000 mBar.

Figure 5 shows a graph illustrating the optimal thermodynamic conditions for processing at various stages of the method of the illustrated embodiment.

As can be seen in Figure 5, optimal processing conditions for HEIR are obtained between 10°C and 40°C and between 200-400 mBar of pressure.

Since chemicals tend to condense more easily at higher pressures and at lower temperatures, by altering the thermodynamic conditions within the processing chamber 100 at step 703 to lower the temperature and increase the pressure within the interior cavity 106, it is possible to cause the chemical vapour to condense onto the additively manufactured part 10, which subsequently leads to the surface material of the part 10 becoming dissolved by the chemical applied thereto.

Furthermore, during step 703, the sidewalls 104a, 104b of the processing chamber 100 are maintained above the chemical condensation temperature to help avoid chemical vapours from condensing on the chamber sidewalls 104a, 104b rather than onto the additively manufactured part 10, to help reduce wastage and to ensure that any condensation of the chemical vapour is focussed at the part 10, rather than at other areas of the processing chamber 100.

As the chemical is condensed onto the surface of the part 10, the surface of the part 10 undergoes a change of state from a first, undissolved state, in which the movement of the surface material of the part 10 is substantially prevented, to a second, dissolved state, in which the movement of the surface material of the part 10 is permitted.

Once dissolved, the dissolved surface material of the additively manufactured part 10 is then allowed to reflow under the influence of gravity. This material re-distribution closes the pores on the surface of the part, resulting in a smooth, processed surface.

Once the processing step has been completed, the pressure within the interior cavity 106 is again increased during step 704, typically to a pressure equal to or greater than 400mBar, so as to cause any remaining solvent vapour present within the interior cavity 106 of the processing chamber 100 to condense. The higher and more rapid the pressure increase, the quicker and more readily the solvent vapour will condense.

In embodiment illustrated in Figure 1, the pressure within the interior cavity 106 is increase via opening the valve 109d to allow ambient air to flow through the gas inlet 109c and into the interior cavity 106 of the processing chamber 100. However, it shall be appreciated that in other embodiments, the pressure within the interior cavity can instead be increased by selectively introducing an inert gas, such as Nitrogen, into the interior cavity of the processing chamber. For example, in the embodiment illustrated in Figure 3, the pressure within the interior cavity 606 is increased via introducing Nitrogen into the interior cavity 606 of the processing chamber 600 via the inlets 620, 630.

Furthermore, to help encourage the condensation, during step 704 the heaters 108a, 108b are deactivated and the coolers 110a, 110b are activated so as to cool the interior surfaces of the processing chamber 100, typically to a temperature in the range of 10°C to 40°C. This helps to further promote condensation of the remaining solvent vapour present within the processing chamber 100 onto the surfaces of the interior cavity 106, in this case onto the base 102, and also helps to prevent the already condensed solvent within the interior cavity 106 from re-evaporating. However, in other embodiments, it shall be appreciated that the condensation step may comprise adjusting only the pressure or only the temperature of the interior cavity.

The condensed solvent is then allowed to run down the sidewalls 104a, 104b and the base 102 of the processing chamber 100, past the supporting mesh 105, and into the drain 112 which is able to extract the recovered solvent from the processing chamber 100 at step 705.

The recovered solvent is then returned to the solvent reservoir 114 for use in further processing operations, thereby helping to reduce solvent wastage.

In addition, it has also been found that condensing the solvent vapour within the processing chamber (rather than via a condenser) can help to improve the purity of the condensed, recovered solvent since the use of cooling agents, typically associated with unit condensers, can be better avoided.

Whilst the aforementioned method is described in relation to a processing method wherein a single type of solvent is used, in some embodiments, the method may also be performed using a mixture of solvents.

In such embodiments, the condensation step 704 can be performed in multiple stages. In a first stage of the condensation step, the thermodynamic conditions within the processing chamber 100 are adjusted so as to cause the solvent or solvents with the lowest boiling temperature to condense, but so as not to condense the remaining solvent (or solvents).

Since different solvents tend to exhibit different boiling temperatures, it is possible to adjust the pressure and/or temperature conditions within the interior cavity 106 of the processing chamber 100, as has been described above, so that only one or some of the solvents (which make up the solvent mixture) are condensed during the first stage.

The condensed solvent is then recovered in substantially the same manner as has been described above whilst the remaining solvent (or solvents) are maintained in vapour form within the processing chamber.

The process is then repeated for each of the remaining solvents during subsequent stages until substantially all of the solvent vapour within the processing chamber has been condensed and recovered.

Alternatively, using this method, it is also possible to selectively remove one or more solvents (e.g. the solvent or solvents with the lowest boiling point or boiling points) from the processing chamber whilst the remaining solvent or solvents are maintaining within the processing chamber in vapour form, for example for use during further processes.

Although the disclosure has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A method of post-processing an additively manufactured part, the method comprising: locating an additively manufactured part in a processing chamber; introducing a solvent vapour into said processing chamber; performing a processing step, wherein the solvent vapour introduced into the processing chamber is used to process a surface of the additively manufactured part located therein; performing a condensing step, wherein, after the processing step, a pressure and/or temperature within the processing chamber is adjusted so as to cause the solvent present within the processing chamber to condense; and performing a recovery step, wherein the solvent condensed during the condensing step is extracted from the processing chamber.
2. The method according to claim 1, wherein the condensing step comprises cooling an interior of the processing chamber, optionally to a temperature in the range of 10°C to 40°C.
3. The method according to claim 1 or claim 2, wherein the condensing step comprises introducing a gas into the processing chamber so as to increase the pressure therein, optionally to a pressure of at least 400 mBar.
4. The method according to claim 3, wherein the gas introduced into the processing chamber during the condensing step is cooled prior to being introduced into the processing chamber, optionally to a temperature in the range of 10°C to 40°C.
5. The method according to claim 3 or 4, wherein the gas introduced into the processing chamber is directed towards an interior surface of the processing chamber so as to promote condensation of the solvent onto said interior surface of the processing chamber.
6. The method according to any preceding claim, wherein the solvent vapour comprises a first solvent and a second solvent, wherein the condensing step comprises adjusting the pressure and/or temperature within the processing chamber so as to cause the first solvent to condense whilst the second solvent remains in vapour form, and wherein the recovery step comprises extracting the first, condensed solvent from the processing chamber.
7. The method according to any preceding claim, wherein the recovery step comprises collecting the condensed solvent in a solvent reservoir, optionally wherein the solvent reservoir is removable from the processing chamber, and more optionally wherein the solvent reservoir is a solvent cartridge.
8. The method according to claim 7, wherein the solvent reservoir comprises a first compartment for virgin solvent and a second compartment for recovered solvent, and wherein the recovery step comprises returning the condensed solvent to the second compartment of the solvent reservoir.
9. The method according to any preceding claim, further comprising a heating step, performed prior to the processing step, wherein the solvent is heated so as to cause the solvent to vaporise prior to the solvent being introduced into the processing chamber.
10. The method according to any preceding claim, wherein the processing step comprises applying a negative pressure to an interior of the processing chamber.
11. A processing chamber for processing an additively manufactured part, the processing chamber comprising: an interior cavity for receiving an additively manufactured part; a solvent inlet for introducing a solvent into said interior cavity; a condensing mechanism for adjusting a pressure and/or a temperature within the interior cavity so as to cause the solvent present within the interior cavity to condense; and a drain for extracting the condensed solvent from the interior cavity of the processing chamber.
12. The processing chamber of claim 11, wherein the condensing mechanism comprises a cooler, optionally wherein the cooler is arranged so as to cool a surface of the interior cavity of the processing chamber, and further optionally wherein the cooler is arranged so as to cool a base of the interior cavity of the processing chamber.
13. The processing chamber according to claim 11 or claim 12, wherein the condensing mechanism comprises a gas inlet for introducing a gas into the interior cavity of the processing chamber so as to increase the pressure therein, and optionally wherein the gas inlet is arranged so as to direct a flow of gas towards a surface of the interior cavity so as to promote condensation of the solvent onto said surface of the interior cavity.
14. The processing chamber according to claim 13, wherein a cooler is located at, or upstream of, the gas inlet so as to cool the gas prior to introduction into the interior cavity of the processing chamber.
15. The processing chamber according to any of claims 11 to 14, wherein the interior cavity is arranged so as to cause the condensed solvent to flow towards the drain, and optionally wherein the interior cavity comprises a base, wherein the drain is located at the base of the interior cavity, and wherein the base is angled so as to cause condensed solvent present on the base to flow towards the drain.
16. The processing chamber according to any of claims 11 to 15, wherein the interior cavity comprises a surface having a coating having a surface energy less than or equal to 60 mN/m, and further optionally wherein the interior cavity comprises a base, and wherein the surface of said base comprises said coating.
17. The processing chamber according to any of claims 10 to 16, wherein the interior cavity comprises a surface having a texture selected or arranged such that, in use, the contact angle formed between the surface on which the texture has been applied and the solvent condensed onto said surface is greater than 900, optionally greater than 1200, and most optionally greater than 1500, and further optionally wherein the interior cavity comprises a base, the surface of said base comprising said texture.
18. A processing chamber for processing an additively manufactured part, the processing chamber comprising: an interior cavity for receiving an additively manufactured part, the interior cavity comprising a surface; a solvent inlet for introducing a solvent into said interior cavity: and a condensing mechanism for adjusting a pressure and/or a temperature within the interior cavity so as to cause the solvent present within the interior cavity to condense; and wherein the surface of the interior cavity comprises a hydrophobic coating and/ or a hydrophobic texture.
19. The processing chamber according to claim 18, wherein the surface of the interior cavity comprises a hydrophobic coating, and wherein the hydrophobic coating has a surface energy less than or equal to 40 mN/m, and optionally less than or equal to 20 mN/m.
20. The processing chamber according to claim 18 or 19, wherein the surface of the interior cavity comprises a hydrophobic texture, the hydrophobic texture being selected or arranged such that, in use, the contact angle formed between the surface on which the hydrophobic texture has been applied and the solvent condensed onto said surface is greater than 1200, and optionally greater than 150°.
21. The processing chamber according to claim 20, wherein the hydrophobic texture comprises an array of protrusions.
22. The processing chamber according to claim 21, wherein the hydrophobic texture comprises an array of nodules, wherein each nodule has a diameter in the range of 1 micron to 1000 microns, and optionally wherein a spacing between each nodule of the array of nodules is in the range of 10 microns to 10,000 microns.
23. The processing chamber according to any of claims 18 to 22, wherein the interior cavity comprises a base and at least one sidewall, wherein the base and/or the at least one sidewall each comprise a surface defining the surface of the interior cavity and a main body, wherein the surface and the main body each comprise a material, and wherein the material of the surface has a carbon content which is greater than the carbon content of the material of the main body.
24. The processing chamber according to any of claims 18 to 23, wherein the processing chamber comprises a base, and wherein the interior cavity of the processing chamber is arranged so as to cause the condensed solvent to flow towards the base of the processing chamber.
25. The processing chamber according to any of claims 18 to 24, further comprising a drain for extracting the condensed solvent from the interior cavity of the processing chamber, optionally wherein the interior cavity is arranged so as to cause the condensed solvent to flow towards the drain, and further optionally wherein the interior cavity comprises a base, wherein the drain is located at the base of the interior cavity, and wherein the base is angled so as to cause condensed solvent present on the base to flow towards the drain.