Three-dimensional chalcogenide glass printing system

Abstract

The present disclosure concerns a chalcogenide glass article manufacturing system including a crucible comprising a barrel, comprising: an opening, configured to receive chalcogenide glass feedstock and a cavity, configured to contain chalcogenide glass feedstock; a nozzle, in contact with the barrel cavity and the exterior, provided with an aperture, the nozzle being in thermal contact with the barrel; a heater, proximate the nozzle and in thermal contact with the barrel; a removable lid, configured to seal the barrel cavity from the exterior; a cooling mantle, enclosing at least part of the crucible, configured to cool at least part of the outer wall of the barrel, comprising a cooling gas inlet, proximate the crucible opening, and a cooling gas outlet, proximate the nozzle directed towards the nozzle and / or the chalcogenide glass article.

Description

DESCRIPTIONTitleTHREE-DIMENSIONAL CHALCOGENIDE GLASS PRINTING SYSTEMFIELD OF THE DISCLOSURE

[0001] The present disclosure generally relates to chalcogenide glass article manufacturing systems, in particular three-dimensional printing systems for forming chalcogenide glass articles. The present disclosure further relates to a method for manufacturing chalcogenide glass articles, in particular for three-dimensional printing chalcogenide glass articles.BACKGROUND

[0002] In recent years, a growing interest has been developed for optical materials and fibres for the mid-infrared (mid-IR) region, the mid-IR spectral region contains the 3-5 pm and 8-12 pm atmospheric transparent windows, useful for thermal imaging in particular. Vitreous materials containing chalcogen elements, i.e., S, Se and Te, show large transparency windows in the infrared.

[0003] Three-dimensional (3D) printing processes for fabricating mid-IR optical components such as preforms, optical fibres, sensors and beads have been disclosed, based on the fused filamentation fabrication (FFF) method, also known as fused deposition modelling (FDM). This method however limits the available materials to those that can be easily formed into filaments and even for available materials, filament crystallisation and filament breakage remains an issue due to their brittle nature.

[0004] There remains a need in the art for a device and method for the fabrication of chalcogenide glass articles, in particular optical components, that is compatible with a wider range of chalcogenide glass compositions and that is able to produce such articles with a high level of transmittance in the mid-IR region.SUMMARY OF THE DISCLOSURE

[0005] According to at least one aspect of the present disclosure, a chalcogenide glass article manufacturing system, in particular a three-dimensional chalcogenide glass printing system, includes a crucible comprisinga. a barrel, comprisingi. an opening, configured to receive chalcogenide glass feedstock and ii. a cavity, configured to contain chalcogenide glass feedstock;b. a nozzle, in contact with the barrel cavity and the exterior, provided with an aperture, the nozzle being in thermal contact with the barrel;c. a heater, proximate the nozzle and in thermal contact with the barrel; d. a removable lid, configured to seal the barrel cavity from the exterior; e. a cooling mantle, enclosing at least part of the crucible, configured to cool at least part of the outer wall of the barrel, comprisingi. a cooling gas inlet, proximate the crucible opening, andii. a cooling gas outlet, proximate the nozzle directed towards the nozzle and / or the chalcogenide glass article.

[0006] In three-dimensional chalcogenide glass printing, a continuous filament of glass is extruded. Discontinuous printing results in multiple interfaces at contact points between individual beads, resulting in a deterioration of optical properties. Discontinuities may further have a detrimental effect on layer adhesion .

[0007] According to another aspect of the present disclosure, a method of operating a chalcogenide glass article manufacturing system, in particular a chalcogenide glass article manufacturing system according to an embodiment or combination of embodiments of the present invention, includes the steps ofa. Providing a chalcogenide glass feedstock and a first protective gas in a cavity of the barrelb. heating said chalcogenide glass feedstock within the crucible cavity c. cooling at least part of the outer wall of the barrel by providing a second protective gas flow to a cooling gas inlet in the cooling mantle, proximate the crucible opening, the cooling mantle enclosing at least part of the barrel, d. extruding the chalcogenide glass feedstock through an aperture of the nozzle as a filament onto a build plate, while directing the second protective gas through a cooling gas outlet, towards the extruded glass, ande. moving the build plate relative to the nozzle.

[0008] The inventors have found that such a chalcogenide glass article manufacturing system and method permits the three-dimensional printing of chalcogenide glass articles and may provide one or more of the following advantages:a. Increased feedstock variety. Feedstock other than fibres can be used, eliminating the need for a fibre fabrication step. Also glass compositions that are difficult to provide and use in the form of fibres can be used and filament crystallisation and breakage are avoided. Feedstock can be in the shape of chalcogenide glass rods, but can also be chalcogenide glass powder, chalcogenide glass ingots, recycled chalcogenide glass ingots or recycled chalcogenide glass articles.b. Simplified crucible support. Attachment of the crucible to a crucible support is simplified as less heat is transferred from the heater to the crucible support.c. Reduction of protective gas usage. Protective gas consumption is reduced as the cooling gas also serves to prevent contact of extruded glass with reactive gases and / or humidity.d. Stress reduction. Cooling gas arriving at the extruded glass has been heated and thus reduces risk of generating stress in the extruded glass article.e. Improved quality of printed glass articles. Attenuation may be reduced and dimensional control of printed articles may be improved by good viscosity control and cooling control. A minimum attenuation of less than 5 dB / m in the wavelength range from 2 to 12 pm may be obtained. The minimum attenuation in this range may even be less than 4 dB / m, less than 3 dB / m, or even less than 2dB / m.f. Chemical composition of the printed glass article may be less altered through undesired loss of volatile elements and / or oxidation.

[0009] These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following is a description of the figures in the accompanying drawings.

[0011] The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

[0012] FIG. 1 is a schematic cross-sectional representation of a crucible in a chalcogenide glass article manufacturing system according to an embodiment of the present invention.

[0013] FIG. 2 is a partial schematic cross-sectional representation of a prior art 3D chalcogenide glass printing system.

[0014] FIG; 3 are attenuation spectra of initial chalcogenide glass, of chalcogenide glass filament extruded from a device according to embodiments of the present disclosure and of comparative chalcogenide glass filament.

[0015] FIG. 4 is a schematic cross-sectional representation of a crucible in a chalcogenide glass article manufacturing system according to an embodiment of the present invention.DETAILED DESCRIPTION

[0016] For purposes of description herein, the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and derivatives thereof shall relate to the concepts as oriented in FIG. 1. However, it is to be understood that the concepts may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to theembodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0017] The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to an three-dimensional printing system. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

[0018] As used herein, the term “and / or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items, can be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0019] In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises”, “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0020] As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term “about” is used in describing a valueor an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to.

[0021] Whether or not a numerical value or end-point of a range in the specification recites “about,” the numerical value or end-point of a range is intended to include two embodiments: one modified by “about,” and one not modified by “about.” It will be further understood that the end-points of each of the ranges are significant both in relation to the other end-point, and independently of the other endpoint.

[0022] The terms “substantial”, “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially” may denote values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

[0023] As used herein the terms “the”, “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary. Thus, for example, reference to “a component” includes embodiments having two or more such components unless the context clearly indicates otherwise.

[0024] Referring to Fig. 1 , the barrel (1) receives the chalcogenide glass feedstock (7) through the opening. The lid (6) hermetically seals the crucible opening from the exterior atmosphere and thus also prevents the feedstock from contact with the exteriors gas phase.

[0025] The barrel may be substantially cylindrical shaped and the cooling mantle (2) co-axially arranged relative to a main axis of the barrel. The barrel opening an nozzle may be arrange at opposite ends of the barrel.

[0026] The crucible of the present invention may further comprise a barrel protective gas inlet (8) in fluid communication with the barrel cavity (11). The barrel protective gas further prevents undesired reactions of the glass in the crucible cavity for example with oxygen and / or water from the exterior atmosphere.

[0027] Extruding the chalcogenide glass feedstock through an aperture of the nozzle (4) as a filament onto a substrate may be performed by gravity.

[0028] Extruding the chalcogenide glass feedstock through an aperture of the nozzle as a filament onto a substrate may be performed by setting a gas pressure in the barrel cavity, in particular using the barrel protective gas.

[0029] Referring to Fig. 4, molten feedstock (7’) is continuously extruded as a continuous chalcogenide glass filament (12).

[0030] A first protective gas source may be fluidly connected to the barrel protective gas inlet.

[0031] The heater (3) is in thermal contact with the barrel (1) and may further be in thermal contact with the nozzle (4), such that thermal energy provided by the heater may be transferred to the chalcogenide glass feedstock and to the glass flowing through the nozzle. The heater heats the chalcogenide glass feedstock in the barrel and optionally proximate the nozzle to form a melt pool of chalcogenide glass.

[0032] Thermal contact can occur through one or more of the following: direct physical contact, indirect contact such as convection of the cooling gas and radiative contact.

[0033] The heater may be a resistive heater. The barrel may thereby be radiatively heated.

[0034] The crucible may further comprise a gas outlet (12). Protective gas and / or gases produced upon heating the chalcogenide glass feedstock may be evacuated through the gas outlet. The gas outlet may be open for the purpose of purging the barrel cavity and may be closed at least partly to build up gas pressure for the extraction of molten glass.

[0035] The chalcogenide glass article manufacturing system may further comprise a crucible support structure (5). The crucible may be held to the crucible support structure via the cooling mantle (2). Thus direct contact between the heated barrel and the crucible support structure is avoided.

[0036] The quality regarding glass composition and dimensional control relies on the presence and control of protective gas sources and on the control of the temperature during melting and extrusion to obtain the desired viscosity and during cooling.

[0037] In an embodiment of the chalcogenide glass article manufacturing system , a second protective gas source may be fluidly connected to the cooling gas inlet (9). With the cooling gas being a protective gas, the cooling gas outlet (10) is preferably directed towards the extruded chalcogenide glass and may thus limit contact of extruded chalcogenide glass with reactive gases and humidity. As the temperature of the cooling gas is raised through contact with heated parts, excessive cooling of extruded chalcogenide glass may be avoided.

[0038] In an embodiment of the chalcogenide glass article manufacturing system, at least one protective gas diffuser (not shown) is provided proximate the nozzle’s tip. The gas provided by the protective gas diffuser may help control the temperature of the nozzle’s tip, in particular lower the temperature of the nozzle’s tip. Precise temperature control at the nozzle allows for precise viscosity control of the extruded glass, which has an impact on layer adhesion, but also on the final dimensions of the printed article. The gas provided by the protective gas diffuser may also limit contact of extruded chalcogenide glass with reactive gases and humidity. Preferably at least two protective gas diffusers are provided proximate the nozzle’s tip. A more uniform temperature control of the nozzle may thus be obtained and / or a more complete protection of extruded glass. The nozzle temperature is relevant for obtaining the desired viscosity of extruded chalcogenide glass.

[0039] The crucible may further comprise one or more temperature sensors.Temperature sensors may be located proximate the nozzle, in the barrel, in the barrel cavity.

[0040] Preferably the nozzle temperature is maintained in a range from 200 to 600 °C.

[0041] In an embodiment of the chalcogenide glass article manufacturing system , a third protective gas source may be fluidly connected to the protective gas diffuser.

[0042] The gas of the first, second, and third protective gas sources may be independently selected from dry air, N2, and Ar or any mixture thereof. Preferably the gas of the first, second, and third protective gas sources may be independently selected from N2 and Ar or any mixture thereof. More preferably the gas of the first, second, and third protective gas sources is Ar. Preferably dry air may have amoisture (H2O) content of less than 200 ppm and N2 and Ar may preferably have a moisture content of less than 200 ppm and an oxygen content of less than 1000 ppm. Ar is particularly preferred as its higher density provides better protection even in the presence of gas turbulence around heated parts.

[0043] The first, second and third protective gas sources may be a single protective gas source.

[0044] The gas flow rate and / or gas pressure of the first protective gas sources may be selected so as to purge the crucible cavity from reactive gases and humidity and / or to obtain a desired glass extraction rate. For purging preferably the gas flow rate f1 of the first protective gas is 0 < f1 < 5l / min. For extraction the pressure of the first protective gas in the barrel cavity may be set at a gauge pressure pgof 0 < pg< WOOmbar.

[0045] In the chalcogenide glass article manufacturing system and method nof the present disclosure, chalcogenide glass is extruded through the nozzle, preferably in a continuous way.

[0046] The gas flow rate of the second protective gas sources may be selected so as to obtain a desired barrel temperature and / or protection of extruded chalcogenide glass from contact reactive gases and humidity a extraction rate. Preferably the gas flow rate f2 of the second protective gas is 0 < f2 < 20l / min.

[0047] The gas flow rate of the third protective gas sources may be selected so as to obtain a desired nozzle temperature and / or protection of extruded chalcogenide glass from contact reactive gases and humidity. Preferably the gas flow rate f3 of the third protective gas is 0 < f3 < 10 l / min.

[0048] The chalcogenide glass article manufacturing system may further comprise a build plate. The glass article may be manufactured on a surface of the build plate or on a substrate held by the build plate.

[0049] The build plate may further comprise a plate heater. The plate heater may heat the build plate up to a temperature ranging from 50 to 400°C. The build plate temperature is set so as to reduce thermal gradients during the manufacture of the chalcogenide glass articles.

[0050] The chalcogenide glass article manufacturing system may further comprise one or more actuators configured to actuate movements of the crucible, the build plate or both. The molten chalcogenide glass is extruded through the nozzle of the crucible, while the one or more actuators actuate movements of the crucible, of the build plate or both. A computer controls these movements such that the extruded molten glass is selectively deposited to form a three-dimensional glass article.

[0051] In some implementations, the actuators actuate the crucible to move in a horizontal plane, in x and y directions and actuate the build plate to move in a vertical z-direction. In other implementations, “polar printing” occurs in which motion occurs in linear r, angular theta, and linear z directions: the actuators (a) actuate the crucible and nozzle to move along a single horizontal “r” axis; (b) actuate the build plate to rotate about its center line in an angular theta direction, and (c) actuate the build platform to move up and vertically in a z direction. In yet other implementations, the crucible is stationary, and the actuators actuate the build plate to move relative to the nozzle.

[0052] The actuators may move the build plate relative to the nozzle at a speed ranging from 0.1 to 20 mm / s.

[0053] The displacement error, that is the difference between the actual displacement of the build plate relative to the nozzle and the machine commanded displacement may be at most 5pm in any direction.

[0054] The chalcogenide glass article manufacturing system may further comprise a protective gas control system using flow rate control, in particular by volume flow rate or mass flow rate, or a back pressure control system. In addition to protecting the glass feedstock, the protecting gas may be used to push the heated glass feedstock through an aperture in the nozzle. Increasing the pressure of the protecting gas in the crucible cavity pushes molten chalcogenide glass through the crucible nozzle. In illustrative implementations, the glass article produced by the selective deposition is transparent in the mid-IR wavelength range.

[0055] Preferably the barrel comprises metal such as stainless steel, a refractory metal or refractory metal alloy.

[0056] The nozzle may comprise brass, stainless steel, platted copper, tempered steel, Ruby. The nozzle may further comprise any one of these materials coated with a diamond like carbon (DLC) coating.

[0057] The barrel cavity may have a volume ranging from 15 to 700cm3.

[0058] The barrel cavity may be of essentially cylindrical shape, in particular having a height h and a diameter d, with h>d, preferably 5 < h / d < 15.

[0059] The heater may enclose only a part of the barrel and cooling mantle, in particular 40 to 70% of the barrel proximate the nozzle. The part of barrel and cooling mantle not enclosed by the heater may thus be kept at a temperature more suitable for being held by the barrel support.

[0060] The build plate, or print bed, of the chalcogenide glass article manufacturing system may further comprise a mold configured to receive the glass extruded from the nozzle. The mold may be in particular be a lens mold. The mold may in particular comprise WC, SiC, aluminosilicate and stainless steel.

[0061] The chalcogenide glass feedstock for the chalcogenide glass article manufacturing system and method of the present invention may be chalcogenide glasses containing the main element combinations as such as for example : As-Se, As-S, Ge-Se, Ge-S, Ge-As-Se, Ge-As-S, As-Se-Te, Ge-Sb-Se, Ge-Sn-Se, Ge-Te, and Ge-As-Se-Te. In particular they may be chalcogenide glasses selected from As4oSeeo, Te2oAs3oSeso, As4oSeo, Ge2oSeso, GeSee, GASIR 1 (Ge22AseSes8), GASIR 2 (Ge2oSbisSe65), GASIR 5 (As4oSeeo), GASIR 3 (Ge^SbisSnySees) (the GASIR series are glass compositions commercialized by Umicore), and Ge As22Se68

[0062] The chalcogenide glasses may have a glass transition temperature Tgranging from 100°C to 350°C.

[0063] The chalcogenide glasses may have a printing viscosity ranging from 5000 to 10Pa.s at a temperature in the range from 200 to 600 °C.

[0064] The nozzle aperture may have a diameter ranging from 1 to 5mm on the inlet side and 100 to 1000pm on the outlet side.

[0065] The method of the present disclosure may further comprise heating the build plate.

[0066] The method of the present disclosure may further comprise at the end of the 3D printing an annealing step. Such a progressive cooling of the printed object may relieve internal stresses and prevent stress-related breakage of the object. Preferably annealing is performed under neutral atmosphere. The annealing step comprises cooling down to room temperature of the printed object over a duration tc. The annealing step may further comprise, prior to the cooling down, a step of maintaining the printed object at about its glass transition temperature for a duration tm. Generally, tc and tm may be chosen so as to efficiently alleviate internal stresses in the printed glass object, depending for example on size, shape and / or composition of the printed object. Duration tc may for example be at least 30 minutes, at least 45 minutes, or at least 60minutes. Duration tm may for example be at least 10 minutes, at least, 20 minutes, at least 30minutes, at least 40minutes, at least 50 minutes or at least 60minutes.

[0067] The chalcogenide glass article manufacturing system and method according to any embodiment or combination of embodiments herein are in particular suitable for chalcogenide glass articles such as preforms for optical fibres, sensors and optical components such as lenses.

[0068] The chalcogenide glass article manufacturing system and method according to any embodiment or combination of embodiments herein provides thus several means for controlling the temperature of the glass at various stages of the process, during melting, during extruding, during cooling. A high quality of printed glass articles, with low attenuation and high dimensional control of printed articles may be improved by adjusting the different parameters of in particular protective gas flows, the heater to the chalcogenide glass composition used.

[0069] The quality of the chalcogenide glass articles may be assessed in particular by one or more of the following criteria:a. Glass transition temperature before and after printing. Usually measured using differential scanning calorimetry (DSC);b. Density may be used to evaluate the absence or level of presence of porosity;c. Absence of crystallisation as seen in X-ray diffraction measurements; d. Infrared transmittance, in particular optical losses, in the mid-IR;e. Reliability of the process, absence of process interruptions;f. Conformity of final dimensions of the printed articles, in particular compared to digital models, absence of deformation;g. Chemical composition conformity, absence or little loss of volatile elements, low level of oxidation, measured for example by scanning electron microscopy - energy dispersive X-ray spectroscopy(SEM-EDS)

[0070] Examples

[0071] Purified glass feedstock of Te2oAs3oSeso (TAS) was used in all examples.

[0072] Attenuation spectra were measured on a Fourier transform Infrared spectrometer (Thermo Fischer IS50, FT-IR) on a glass fibre with a diameter of 250 pm and 1 meter long. The fibre is obtained by stretching on a drawing tower 3D printed cylinder (diameter 8 mm, length 40 mm) of each example.

[0073] Comparative Example. For the comparative example EX1, the 3D-printing set-up is based on a customized commercial RepRap-style 3D printer (Anet A8) upgraded for soft glasses (Fig. 2). Especially, the feeding mechanism is customized for brittle materials. This mechanism is supplied with 400-mm long TAS rod (21) with a diameter of 3.0 mm, produced by the fibre-drawing method. Drive wheels (22) drive the TAS rod through a heating zone (24) so as to extrude chalcogenide glass (25) through a 400 pm nozzle (26). A cooling fan (23) maintains the glass rod upstream of the heater at a temperature compatible with the drive wheels (22). The printer head moves in the X and Z directions and the bed plate in Y direction while depositing the TAS glass as a thin layer on the substrate (not illustrated). The whole process is performed in ambient air. The temperature of the heating elements in the heating zone was adjusted manually and the nozzle outlet was set so as to extrude a filament of 400 pm diameter.

[0074] For invention example EX2, the setup of EX1 was modified by replacing the complete feeding and extrusion system with a crucible schematically represented in Fig. 1. TAS feedstock was introduced into the barrel cavity through the barrel opening which was then sealed by a lid provided with an inlet and an outlet for protective gas and the cavity was flushed with Ar. The heater was set so as to heat the barrel to a temperature of about 350 °C, higher than the Tgof the TAS feedstock, which is about 180°C. Ar gas was provided to the cooling mantle at a flowrate of 2 L / min. The nozzle outlet diameter was 400 pm. The protective gas diffuser proximate the nozzle’s tip provided Ar gas at a flow rate of 10L / min. The protective gas outlet on the lid was then closed and the pressure in the cavity regulated so as to extrude a filament of 400 pm diameter. The bed plate moves in the X, Y and Z directions while depositing the TAS glass as a thin layer on the substrate.

[0075] After deposition, for annealing all samples were kept at their glass transition temperature for 60 minutes and then progressively cooled down to room temperature over a period of 120 min. The comparative example annealing was performed in air, the invention example annealing was performed in an Ar atmosphere.

[0076] For evaluation purposes, the samples (cylinders 8 mm of diameter and 40 mm long) and were drawn into 250 pm fibres and attenuation spectra were measured. As can be seen from Fig. 3. EX1 , shows significantly higher attenuation values over the whole wavelength range from 2 to 12 pm in comparison to the initial glass. These optical losses observed in EX1 are understood to be related to various imperfections such as losses at interfaces of layers of printed glass, impurities. EX2, shows significant lower attenuation values, compared to EX1, while EX2, shows attenuation values that are very close to those of the TAS feedstock in most of the wavelength range. In EX2 a minimum attenuation of less than 2 dB / m is obtained in the wavelength range from 2 to 12 pm.

Claims

CLAIMS

1. Chalcogenide glass article manufacturing system including a crucible comprising a barrel, comprisinga. an opening, configured to receive chalcogenide glass feedstock and b. a cavity, configured to contain chalcogenide glass feedstock;c. a nozzle, in contact with the barrel cavity and the exterior, provided with an aperture, the nozzle being in thermal contact with the barrel; d. a heater, proximate the nozzle and in thermal contact with the barrel; e. a removable lid, configured to seal the barrel cavity from the exterior; f. a cooling mantle, enclosing at least part of the crucible, configured to cool at least part of the outer wall of the barrel, comprisingg. a cooling gas inlet, proximate the crucible opening, andh. a cooling gas outlet, proximate the nozzle directed towards the nozzle and / or the chalcogenide glass article.

2. Chalcogenide glass article manufacturing system according to claim 1 wherein the crucible comprises a barrel protective gas inlet (8) in fluid communication with the barrel cavity (11 ).

3. Chalcogenide glass article manufacturing system according any one preceding claim further comprising a first protective gas source fluidly connected to the barrel protective gas inlet.

4. Chalcogenide glass article manufacturing system according to any one preceding claim wherein the heater (3) is in thermal contact with the barrel (1) and / or in thermal contact with the nozzle (4).

5. Chalcogenide glass article manufacturing system according to any one preceding claim wherein the crucible comprises a gas outlet (12).

6. Chalcogenide glass article manufacturing system according to any one preceding claim further comprising a crucible support structure (5).

7. Chalcogenide glass article manufacturing system according to any one preceding claim comprising a second protective gas source fluidly connected to the cooling gas inlet (9).

8. Chalcogenide glass article manufacturing system according to any one preceding claim comprising at least one protective gas diffuser proximate the nozzle’s tip.

9. Chalcogenide glass article manufacturing system according to any one preceding claim comprising one or more temperature sensors, located proximate the nozzle, in the barrel and / or in the barrel cavity.

10. Chalcogenide glass article manufacturing system according to any one preceding claim comprising a third protective gas source fluidly connected to the protective gas diffuser.

11. Chalcogenide glass article manufacturing system according to any one preceding claim comprising a build plate, optionally comprising a plate heater.

12. Chalcogenide glass article manufacturing system according to any one preceding claim comprising one or more actuators configured to actuate movements of the crucible, the build plate or both.

13. Method of operating a chalcogenide glass article manufacturing system comprises the steps ofa. providing a chalcogenide glass feedstock and a first protective gas in a cavity of a barrel;b. heating said chalcogenide glass feedstock within the crucible cavity; c. cooling at least part of the outer wall of the barrel by providing a second protective gas flow to a cooling gas inlet in the cooling mantle, proximate the crucible opening, the cooling mantle enclosing at least part of the barrel;d. extruding the chalcogenide glass feedstock through an aperture of the nozzle as a filament onto a build plate, while directing the second protective gas through a cooling gas outlet, towards the extruded glass; ande. moving the build plate relative to the nozzle.

14. The method according to claim 13 comprising the step of heating the build plate.

15. The method according to claim 13 or claim 14 of the present comprising an annealing step.

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