Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B29/00—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins
  • C03B29/04—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/002—Thermal treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/10—Processes of additive manufacturing
  • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
  • B29C64/118—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using filamentary material being melted, e.g. fused deposition modelling [FDM]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
  • B29C64/264—Arrangements for irradiation
  • B29C64/268—Arrangements for irradiation using laser beams; using electron beams [EB]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/02—Layered products essentially comprising sheet glass, or glass, slag, or like fibres in the form of fibres or filaments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y10/00—Processes of additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y80/00—Products made by additive manufacturing
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B19/00—Other methods of shaping glass
  • C03B19/02—Other methods of shaping glass by casting molten glass, e.g. injection moulding
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B20/00—Processes specially adapted for the production of quartz or fused silica articles, not otherwise provided for
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/006—Re-forming shaped glass by fusing, e.g. for flame sealing
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
  • C03B37/10—Non-chemical treatment
  • C03B37/12—Non-chemical treatment of fibres or filaments during winding up
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
  • C03B37/10—Non-chemical treatment
  • C03B37/14—Re-forming fibres or filaments, i.e. changing their shape
  • C03B37/15—Re-forming fibres or filaments, i.e. changing their shape with heat application, e.g. for making optical fibres
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/10—Coating
  • C03C25/24—Coatings containing organic materials
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/10—Coating
  • C03C25/24—Coatings containing organic materials
  • C03C25/25—Non-macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/10—Coating
  • C03C25/24—Coatings containing organic materials
  • C03C25/26—Macromolecular compounds or prepolymers
  • C03C25/28—Macromolecular compounds or prepolymers obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C03C25/30—Polyolefins
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/10—Coating
  • C03C25/24—Coatings containing organic materials
  • C03C25/26—Macromolecular compounds or prepolymers
  • C03C25/32—Macromolecular compounds or prepolymers obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/10—Coating
  • C03C25/24—Coatings containing organic materials
  • C03C25/26—Macromolecular compounds or prepolymers
  • C03C25/32—Macromolecular compounds or prepolymers obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
  • C03C25/321—Starch; Starch derivatives
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
  • C03C25/10—Coating
  • C03C25/24—Coatings containing organic materials
  • C03C25/40—Organo-silicon compounds
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2201/00—Type of glass produced
  • C03B2201/02—Pure silica glass, e.g. pure fused quartz

Definitions

• the present invention relates to a method for producing a dreidimensi onalen object made of glass, in particular made of quartz glass, comprising a Umfor men a glass fiber, wherein the glass fiber provided with a protective jacket is continuously fed to a heat source, the protective jacket is removed under the action of heat and the glass fiber is softened.
• the invention also relates to a glass fiber for the manufacture of a three-dimensional object made of glass, the glass fiber being provided with a protective jacket.
• additive manufacturing techniques that enable the rapid production of complex geometries without complex tools are becoming increasingly important.
• additive manufacturing techniques are stereolithography, selective laser melting or sintering, and three-dimensional printing.
• solid, liquid or powdery raw materials are spatially and temporally controlled on a base (substrate, platform) and put together in layers to form real three-dimensional objects.
• the first additive manufacturing techniques for the production of glass have used shapeless starting materials, such as glass powder or glass melt.
• Junjie beat Luo; Luke J. Gilbert; Douglas A. Bristow; Robert G. Landers; Jonathan T. Goldstein; Augustine M. Urbas; Edward C. Kinzel in "Additive manufacturing of glass for optical applications” (Laser 3D Manufacturing III, Proc. Of SPIE, Vol. 9738, 2016) proposed the production of objects made of quartz glass by successively welding on quartz glass filaments.
• the filaments which consist of uncoated quartz glass fibers with a nominal outer diameter of 0.5 mm, are fed in a straight line to a beam of a C0 2 laser, melted therein and welded onto a substrate in layers to form a glass object.
• uncoated quartz glass fibers are fragile and must not be bent during handling and processing, which prevents, for example, the storage and unwinding of the glass filaments from a winding spool.
• a 0.4 mm thick glass fiber with a fiber core made of quartz glass and a 50 .mu.m thick protective plastic jacket is fed virtually endlessly from a winding reel to a defocused beam of a CO 2 laser.
• the protective sheath is burned off by the laser beam before the quartz glass of the fiber core melts.
• EP 3 034 480 A1 deals with the production of bioactive tissues and substances from glass fibers for use in medical and dental medicine see area.
• the bioactive glass fiber can also be coated with a bioactive substance at least 250 nm thick, such as collagen I, which is easily absorbed in the body.
• a glass fiber with a layer of a saturated higher fatty acid and / or of an alkylpolysiloxane is known.
• the layer thickness is about 0.1 pm.
• the thickness of approx. 60 ⁇ m for the protective jacket is a standard thickness for optical glass fibers, which is applied, for example, as a UV-curable coating during the fiber drawing process. This thickness is necessary to protect the fiber mechanically and optically from degradation in the long term.
• Plastic residues from the protective jacket in the 3D object are, however, not acceptable; complete removal is required.
• the protective plastic jacket burns off, large quantities of gases and impurities are produced, which are deposited on the surrounding surfaces and prevent or make it more difficult for the quartz glass fibers to fuse without bubbles and without a gap.
• the glass fiber provided with a standard plastic protective jacket shows a strong tendency to deform when heated.
• twisting of the glass fiber around the longitudinal axis of the fiber makes it difficult to maintain the target contour of the glass object specified by the model and, for example, the straight welding onto the base.
• the invention is therefore based on the object of specifying a manufacturing method using glass filaments, in particular quartz glass fibers, which is economical and which facilitates the production of filigree or optically distortion-free and transparent glass objects, and in particular also the setting of optical and mechanical properties with high spatial resolution.
• the invention is based on the object of providing a glass fiber, in particular a glass fiber made of quartz glass, which is particularly adapted and suitable for use in the manufacturing method according to the invention.
• this object is achieved according to the invention based on a method of the type mentioned at the outset in that the glass fiber has a protective jacket with a layer thickness in the range from 10 nm to 10 ⁇ m.
• the glass fiber can be used to produce a three-dimensional object made of glass, in particular made of quartz glass.
• the manufacturing process using glass filaments is also referred to below as the "build-up welding process”.
• the use of a glass fiber provided with a protective sheath according to the invention has several advantages:
• the thickness of the protective jacket of at least 10 nm, preferably at least 50 nm, is sufficient to protect the glass fiber from mechanical damage when used as an intermediate product, as here.
• it can be stored on a winding roll with a winding diameter of less than 30 cm and continuously unwound from this during the build-up welding process and fed to the heating source.
• the glass fiber has, for example, a diameter in the range from 20 ⁇ m to 1000 ⁇ m, preferably a diameter in the range from 50 ⁇ m to 300 ⁇ m.
• the information on the diameter of the glass fiber refers here and below to the diameter without the protective jacket.
• the information on the diameter of the glass fiber relate to the diameter of the circumference surrounding the contour.
• the protective jacket is removed from the glass fiber immediately before the glass fiber is melted under the action of the heat from the heat source and without mechanical contact with a tool.
• the removal takes place, for example, by evaporation and optionally supported by burning (pyrolysis) of components of the protective jacket.
• the protective jacket is removed solely under the action of the heating source that is also used to soften the glass fiber.
• additional heat sources or other aids can also be used, which are particularly adapted for the oxidative combustion of the protective jacket, for example.
• the small thickness of the protective jacket also makes it possible to keep the length section short in which the protective jacket is removed as a result of the action of the heating source.
• this length section the glass fiber must no longer be bent or touched so that it cannot be damaged or broken.
• This length section is therefore as short as possible and preferably has a length in the range from 0.5 to 2 cm.
• the glass fiber freed from the thin protective sheath shows no appreciable tendency to deform, which simplifies fiber guidance and enables higher positioning accuracy and true-to-contour shaping or welding of the fiber layer, and in particular also straight-line welding on a base . This facilitates the production of optically distortion-free glass objects and compliance with the optical and mechanical properties prescribed by the model.
• Protective sheath of small thickness allows a comparatively high feed rate of the glass fiber to the heating source, which is preferably at least 300 mm / min, preferably at least 450 mm / min.
• the high feed rate made possible by the thin protective jacket ensures that the build-up welding process can be carried out economically with a high mass separation rate.
• the protective jacket preferably contains only the components carbon, silicon, hydrogen, nitrogen and oxygen. These components can be removed without residue via the gas phase. The formation of toxic substances or undesirable soot particles and solids, which lead to contamination of the glass object, is avoided.
• the protective jacket contains an organic material with a decomposition temperature of less than 400 ° C.
• the protective jacket is removed, for example, completely or at least partially by thermal decomposition of the protective jacket material, usually in combination with an oxidation reaction.
• Suitable organic materials which are characterized by a low decomposition temperature are polysaccharides or surfactants, in particular cationic surfactants or polyether polymers such as polyethylene glycol, polyalkylene glycol, polyethylene oxide and / or polyalkylene oxide.
• the protective jacket is produced from one or more fluorine-free silanes and / or from fluorine-free surfactants, in particular cationic fluorine-free surfactants.
• the starting substances are free of fluorine, the release of fluorine and the reaction to hydrofluoric acid and the associated corrosive attack on the glass of the glass fiber or the three-dimensional glass object are avoided when the protective jacket is removed.
• the protective sheath is usually applied directly to the freshly drawn glass fiber during the fiber drawing process by passing it through a coating cuvette in which the protective sheath material is contained in monomeric, liquid form.
• the glass fiber wetted with the monomer leaves the coating cuvette via a nozzle that determines the thickness of the adhering monomer layer and wipes off the excess monomer material.
• a minimum distance must be maintained between the nozzle wall and the glass fiber, which determines the minimum thickness of the protective jacket after the monomer layer has hardened.
• a protective sheath with a small thickness is produced on the glass fiber, which was difficult to adjust via a nozzle because of the requirement of said minimum distance. Therefore, the protective jacket is preferably produced by dipping or by roller coating on the glass fiber.
• the protective sheath is not applied to the glass fiber via a nozzle, but rather by dipping the glass fiber into a bath containing a coating solution from which the protective sheath is created, or by guiding the glass fiber onto a roller surface on which a film is formed the coating solution is located. Since the protective jacket only has to guarantee temporary mechanical protection, it can also be produced with thin, for example aqueous, coating solutions.
• the heat source is used to melt the glass fiber, it supports or causes the removal of the protective jacket and it softens the surface of the base, if any, present during build-up welding and thus promotes the adhesion between melted glass of the glass fiber on the base.
• a laser beam as a heat source, it has proven useful if the glass fiber longitudinal axis encloses an angle in the range between 30 and 100 degrees with the main direction of propagation of the laser beam. This angle influences the beginning of the area of action of the laser beam on the protective jacket. The more acute the angle, the earlier the laser beam heats the protective jacket.
• the technical problem given above is achieved according to the invention based on a glass fiber of the type mentioned at the beginning in that the glass fiber has a protective jacket with a layer thickness in the range from 10 nm to 10 ⁇ m.
• the glass fiber provided with a protective jacket according to the invention is particularly suitable as an intermediate product for use in an additive manufacturing process, such as, for example, in a build-up welding process, and in particular in a method according to the present invention, as described in more detail above:
• the thickness of the protective jacket of at least 10 nm, preferably at least 50 nm, is sufficient to protect the glass fiber from mechanical damage as an intermediate product.
• it can be stocked with a diameter in the range from 20 ⁇ m to 1000 ⁇ m, preferably with a diameter in the range from 50 to 300 ⁇ m on a winding roll with a winding diameter of less than 30 cm, and continuously from this will be handled.
• the protective jacket has a thickness of less than 10 ⁇ m, preferably less than 5 ⁇ m, particularly preferably less than 1 ⁇ m. It is comparatively thin and can be evaporated and / or pyrolyzed as quickly as possible without leaving any residue.
• the glass fiber which has been freed from the thin protective sheath, shows no significant tendency to deform, which simplifies fiber guidance in the build-up welding process and increases positioning accuracy and true-to-contour shaping or welding of the fiber layer, and in particular also straight welding on a base or precise solidification in air enables.
• the use of the glass fiber according to the invention in a build-up welding process facilitates the production of optically distortion-free glass objects and compliance with the optical and mechanical properties specified by the model. As well as a comparatively high feed rate of the glass fiber to the Schuquel le and thus an economic feasibility of the build-up welding process with a high mass separation rate.
• the glass fiber (synonymous with "glass filament”) consists of glass.
• the glass is, for example, a one-component glass such as quartz glass or it is a multi-component glass such as borosilicate glass.
• the one-component glass can contain additional Do animal substances. Quartz glass is understood here to mean a glass which has an Si0 2 content of at least 90% by weight.
• the glass fiber is solid or it contains a hollow channel or several hollow channels (hereinafter also referred to as “capillary”) or a doped core.
• the central axis of the hollow channel preferably runs in the longitudinal axis of the fiber.
• the glass fiber (or the capillary) has a cross-section (with a view of the longitudinal axis of the fiber) that is circular or non-circular.
• the non-circular cross-section is, for example, oval, polygonal, in particular square, right-angled, hexagonal, octagonal or it is trapezoidal, grooved, star-shaped or it has flattened areas on one side or on several sides or inward (concave) or outward (convex) curved surfaces.
• FIG. 1 shows a first embodiment of the experimental set-up for carrying out experiments on build-up welding using glass filaments according to the invention
• FIG. 2 shows a microscope image of a preliminary build-up welding test using a reference glass fiber
• FIG. 3 shows a micrograph of a preliminary build-up welding test using a glass fiber according to the invention
• FIG. 4 shows a further embodiment of the experimental setup for carrying out experiments on build-up welding using glass filaments according to the invention.
• Quartz glass fibers with a diameter of 220 ⁇ m and a standard plastic jacket with a thickness of approx. 62.5 ⁇ m were used as reference fibers "R", and these with quartz glass fibers of the same diameter but with a thin coating according to the invention carried out (glass fibers 2).
• the coating has a thickness of less than 50 nm. Its composition and production are explained in more detail below.
• the quartz glass fibers (R; 2) were each placed directly on a quartz glass plate and fixed with an adhesive strip.
• An oxyhydrogen heating burner was used as the heat source to soften the quartz glass fibers and to burn away the coatings.
• the oxyhydrogen burner supplies the heat required to melt the quartz glass fibers and, at the same time, oxygen for the pyrolysis of the protective jacket by means of hyperstoichiometric oxygen in the oxyhydrogen gas.
• the reference glass fiber "R” always moves and twists under the influence of the heating burner. This is due to the resulting gases as well as non-axial stresses that are caused by the uneven burning of the coating. Therefore, the fiber ends were attached to the quartz glass plate with adhesive tape before welding in order to at least restrict this movement. The glass fibers 2 with a thin coating did not show this behavior. This glass fiber 2 was much easier to handle during welding and also did not have to be fixed.
• Both types of fibers could be welded onto the substrate 7.
• the reference glass fibers R could not be welded onto the substrate 7 in a straight line.
• the waviness of the welded-on fibers in the reference glass fiber was 5 mm per 120 mm weld length, and in the case of the glass fiber 2 according to the invention there was a very straight weld without any significant waviness.
• the bright reflections 26 of the recording of FIG. 2 make the twisting of the reference glass fiber on the base clear.
• the black points 27 also show that the reference glass fiber R produced more bubbles along the weld length than with the glass fiber 2 according to the invention. Twenty-one bubbles were counted with the reference glass fiber R over a length of 5 cm.
• FIG. 3 shows the result of the welding test using the glass fiber 2 according to the invention. This shows a straight course along the welding length and also a small number of only six bubbles over a length of 5 cm.
• FIG. 1 shows schematically the experimental setup for carrying out the additive manufacturing of a glass object 1 by build-up welding using a glass fiber 2 determined to be suitable on the basis of the preliminary tests.
• the glass fiber 2 wound on a winding spool with a minimum diameter of 30 cm is continuously unwound from the winding spool by means of a fiber guide system (not shown in the figure) and fed through a guide sleeve 24 to a melting zone 6a, in which a defocused laser beam 3 as Heating source is used.
• the defocusing which is indicated in the figure as a dashed line around the laser beam 3, peaks in the heat distribution are compensated.
• the laser beam 3 at the point of impact is approximately twice as wide as the diameter of the glass fiber 3 to be melted, see above that both the glass fiber 3 and the surrounding area and in particular the substrate 7 are heated.
• the glass fiber longitudinal axis 21 forms an angle of approximately 90 degrees with the main direction of propagation 31 of the laser beam 3.
• a CO2 laser with a maximum output power of 120 W is used as the laser.
• the laser beam 3 melts the end of the glass fiber 2 continuously, and it heats the protective jacket 22 of the glass fiber so that it is thermally decomposed. It also softens the surface of the substrate 7 and thus promotes the adhesion between melted glass of the glass fiber 2 and the glass substrate 7.
• the heating zone generated by the laser beam 3 is indicated schematically in FIG. 1 by the area 6b with a gray background.
• a suction tube 5 projects as close as possible to the melting zone 6a.
• the platform consisting of a glass substrate 7 rests on a numerically controlled displacement table (indicated by the x-y-z coordinate system 4) and is displaceable in all spatial directions.
• the glass fiber 2 has a circular cross section and a diameter of 220 ⁇ m. It is provided with a very thin coating 22 with a thickness of less than 100 nm.
• the (thin) layer 22 is produced by pulling the glass fiber 2 through a 10 percent aqueous solution of cetyltrimethylammonium chloride.
• Layer 22 has a decomposition temperature of less than 400 ° C. It is so thin that it can be burned off quickly and efficiently online, directly in front of the melting zone 6a, while the glass fiber 2 is fed further and continuously to the melting zone 6a.
• the glass fiber feed rate to the melting zone 6a is set to a value in the range from 300 to 600 mm / min so that the coating 22 is always completely removed before the glass fiber 2 reaches the melting zone 6a, and also so that the Circuitnab cut 23, in which the coating 22 has already been completely removed, a length less than 2 cm. This prevents mechanical damage to the uncoated glass fiber 2.
• the result of the welding of the glass fiber 2 and the substrate 7 is a three-dimensional glass object 1 without defects and bubbles.
• FIG. 4 schematically shows a modification of the experimental setup for carrying out the additive manufacturing of a glass object.
• the same reference numerals are used as in Figure 1 to designate identical or equivalent Be constituents of the structure.
• the glass fiber longitudinal axis 21 encloses a somewhat more acute angle of 45 degrees with the main direction of propagation 31 of the laser beam 3.
• the heating area 6b also shows a different expansion and a different focus. It sweeps over a larger area of the glass fiber 2 and thereby causes more effective heating of the glass fiber 2 and protective jacket 22 at the same temperature. In this case too, the suction tube 5 is brought as close as possible to the melting zone 6a.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Organic Chemistry (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Mechanical Engineering (AREA)
• Plasma & Fusion (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Thermal Sciences (AREA)
• Glass Melting And Manufacturing (AREA)
• Manufacture, Treatment Of Glass Fibers (AREA)
• Surface Treatment Of Glass Fibres Or Filaments (AREA)

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Publications (1)

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Cited By (2)

Citations (2)

Family Cites Families (22)

• 2019
  • 2019-06-27 EP EP19182983.7A patent/EP3757081A1/de not_active Withdrawn
• 2020
  • 2020-04-30 JP JP2021576967A patent/JP7541539B2/ja active Active
  • 2020-04-30 EP EP20720914.9A patent/EP3990410A1/de active Pending
  • 2020-04-30 US US17/623,062 patent/US20220267188A1/en not_active Abandoned
  • 2020-04-30 CN CN202080035199.5A patent/CN113840809B/zh active Active
  • 2020-04-30 WO PCT/EP2020/062022 patent/WO2020259898A1/de not_active Ceased

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