WO2020109280A1 - Fabrication additive de corps façonnés tridimensionnels au moyen de filaments à facteur de forme élevé - Google Patents

Fabrication additive de corps façonnés tridimensionnels au moyen de filaments à facteur de forme élevé Download PDF

Info

Publication number
WO2020109280A1
WO2020109280A1 PCT/EP2019/082525 EP2019082525W WO2020109280A1 WO 2020109280 A1 WO2020109280 A1 WO 2020109280A1 EP 2019082525 W EP2019082525 W EP 2019082525W WO 2020109280 A1 WO2020109280 A1 WO 2020109280A1
Authority
WO
WIPO (PCT)
Prior art keywords
filament
unit
print head
width
printhead
Prior art date
Application number
PCT/EP2019/082525
Other languages
German (de)
English (en)
Inventor
Dirk Achten
Nicolas Degiorgio
Jonas KÜNZEL
Robert Maleika
Thomas BÜSGEN
Maximilian Wolf
Original Assignee
Covestro Deutschland Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Covestro Deutschland Ag filed Critical Covestro Deutschland Ag
Publication of WO2020109280A1 publication Critical patent/WO2020109280A1/fr

Links

Classifications

    • 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
    • B29C64/205—Means for applying layers
    • B29C64/209—Heads; Nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D 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 [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y70/00—Materials specially adapted for additive manufacturing
    • 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
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/307—Handling of material to be used in additive manufacturing
    • B29C64/321—Feeding

Definitions

  • the present invention relates to an FDM print head for producing 3-dimensional shaped bodies in a 3D printer, which is set up to process an asymmetrical filament with an aspect ratio of> 1.5 to ⁇ 1000.
  • the invention also relates to a 3D printer with such a printhead, an FDM method using the printhead.
  • additive manufacturing of molded articles has become increasingly important in the industrial environment.
  • a very high degree of design freedom is paired with low storage and tool costs, which significantly improves the economy of very small series or individual pieces compared to well-known manufacturing processes, such as injection molding.
  • plastics are heated above their melting temperature and extruded in layers or at points from a nozzle.
  • the position of the printhead and thus also the location of the melt can be individually controlled via a computer using a CAD program, so that after solidification of the melt on a surface or repeated discharge on layers already deposited, 3D objects of even complex geometries can be obtained .
  • the achievable resolution of the objects is a function of the original data resolution, the motor function of the print head, the nozzle shape and the material properties of the polymer used.
  • the disadvantage of the method is that sequential production is very time-consuming and the functionality of the valuables is not always guaranteed as desired. There is a close interaction between functionality and expenditure of time, which in practice requires a targeted coordination between material, material processing and the parameters of the printing process such as temperature and discharge. This optimization is essential to create optically homogeneous moldings with uniform mechanical properties using 3D printing.
  • WO 2016 170 030 A1 discloses a method for producing a three-dimensional object, the outer surface of which comprises at least one surface section which is produced by first producing a surface section in two-dimensional form on a flat base plate (5) by means of an additive manufacturing method, comprising the following steps: I) applying at least one curable polymer or curable reaction resin, each with a modulus of elasticity according to DIN 53504 (Stand April 18, 2015) in the hardened state of ⁇ 250 MPa in flowable form as material webs on a flat base plate (5) by means of a layer-forming molding process for creating a first layer (6); II) applying a second layer (7) to the first layer (6) by means of the same or a different layer-forming molding process as in step I); III) optionally applying from 1 to 48 further layers in accordance with step II), in each case a new layer being applied to the previous layer; IV) curing the layers; V) detaching the hardened surface section from the flat base plate (5); VI) shaping the hardened
  • WO 2018 158 239 A1 discloses a print head for an additive melt layering process with a thermoplastic construction material, comprising: at least one entrance for receiving a construction material into the print head; - At least one melting area arranged after the entrance and at least temporarily fluidly connected to the entrance for melting the building material; and at least one first outlet, which is at least temporarily fluidly connected to the melting area, for discharging melted building material at a first discharge rate from the melting area; wherein the printhead further comprises at least one second outlet, which is at least temporarily fluidly connected to the melting area, for discharging melted or non-melted building material at a second discharge rate from the melting area; and - the first discharge rate can be influenced by a first discharge rate influencer for the molten building material.
  • EP 2 483 060 B1 relates to a system comprising: an extrusion-based digital production system and a consumable, the consumable having a ribbon thread, the ribbon thread having a length and a non-cylindrical cross-sectional profile, the cross-sectional profile having a rectangular geometry with a cross-sectional shape Width to thickness aspect ratio of about 2: 1 or greater, the cross-sectional profile configured to match a corresponding rectangular geometry of a non-cylindrical condenser of the extrusion-based digital manufacturing system, the condenser having an entrance cross-sectional area Ae and one hydraulic diameter Dh, where Dh ⁇ 0.95 ⁇ VAc, to bring about a reaction time with the non-cylindrical condenser that is at least 1.5 times faster than the reaction time with a cylindrical thread in a cylindrical condenser for a same thermally limited, maximum volumetric flow rate can be achieved.
  • Another object of the invention is to provide a method which enables time-efficient production of 3D printed products. Furthermore, it is the object of the present invention to provide a 3D printing head and 3D printer for producing these products.
  • a printhead according to claim 1, a 3D printer according to claim 7 and a method according to claim 8 are therefore proposed.
  • Advantageous further developments are specified in the subclaims. They can be combined as required, unless the context clearly indicates the opposite.
  • a print head according to the invention for producing 3-dimensional shaped bodies in a 3D printer has at least one feed unit for a filament, a melting unit for melting the filament and a print head nozzle.
  • the feed unit and the reflow unit are set up to process an asymmetrical filament with an aspect ratio of> 1.5 and ⁇ 1000 and a cooling unit is arranged between the feed unit and the reflow unit, through which the filament is guided to the reflow unit.
  • a 3D printer has a print head according to the invention.
  • the 3D printer can have further elements such as positioning and control units.
  • a method for additive manufacturing of 3-dimensional shaped bodies by means of fused deposition modeling comprises at least the following steps: a) Providing a filament comprising a polymeric material with a filament aspect ratio Apii ament , calculated as a quotient of filament width and thickness, of> 1.5 and ⁇ 1000, preferably> 10 and ⁇ 800, particularly preferably of> 100 and ⁇ 500; b) feeding the filament to a printhead according to the invention; and c) one or more layers of filament melted out in the printhead through the print head nozzle of the print head to obtain the shaped body.
  • the invention has several advantages over the prior art.
  • asymmetrical filaments with the aspect ratios specified above, significantly more homogeneous printed moldings can be obtained and the printing speed can be increased significantly compared to conventional 3D printing processes. So there are cheaper products available, which are also characterized by improved mechanical and optical quality.
  • the process and product advantages are attributed, on the one hand, to the fact that the aspect filaments have an improved surface-to-volume ratio compared to the round or oval filaments usually used.
  • Round or oval filaments from the prior art have a particularly small surface area due to their symmetry per volume. This can be advantageous in the production, the material logistics of the filaments, but it leads to the fact that there are thick filaments with unfavorable surface properties for 3D printing.
  • the surface-to-volume ratio is increased compared to the known filaments, since a larger surface volume is available per amount of material.
  • the increased surface volume can be used to heat, melt or melt the same amount of material faster and more evenly.
  • the rheology of the molten polymer discharge appears to be influenced not only by the thermal but also by the shear history of the filament.
  • the adapted filament geometry enables a significantly more uniform shear history to be set for the individual volume elements, so that the alignment of the polymer chains is more defined compared to "uneven", round or oval filaments with a thick core.
  • the extrusion process takes place with evenly aligned polymer chains, which can contribute to more uniform material properties. Overall, this results in a faster and more homogeneous melting and extrusion process, which can lead to cheaper and more uniform workpieces.
  • the method according to the invention is a method for additive manufacturing of 3-dimensional shaped bodies. Additive processes as such are known from the prior art. Additive manufacturing is a process in which a component is built up in layers based on digital 3D design data by storing material. It differs from conventional, abrasive manufacturing methods.
  • additive manufacturing is understood in particular to mean FDM (fused deposition modeling), FDM ("fused filament fabrication”) or FFF ("fused filament fabrication”). All in all, processes that are not based on melting or sintering powders or particles, but that work with macroscopic filaments as a material carrier. 3-dimensional moldings are workpieces of any geometry, which extend in three spatial directions.
  • the cooling unit makes it possible to simultaneously obtain a homogeneous melt in the melting unit and a thermoplastic polymer material which is not present in the contact-adhesive area and has the aspect ratios described with the resulting advantages outside of the melting unit.
  • the method according to the invention requires the provision of a filament comprising a polymeric material with a filament aspect ratio A FUament , calculated as the quotient of the filament width and thickness, of> 1.5 and ⁇ 1000, preferably> 10 and ⁇ 800, particularly preferably of> 100 and ⁇ 500.
  • a filament to be used according to the invention is a macroscopic “continuous fiber”, which can expediently be made up on a roll.
  • the dimension of the filament which is characterized by its length, does not contribute to determining the aspect ratio.
  • the aspect ratio according to the invention does not change numerically if the filament is 50 cm, 2 m or 50 m long. To determine the aspect ratio, only two other filament lengths can be used Filament axes contribute.
  • the filament can have a rectangular cross section with two sides of different lengths, the ratio of the two sides, that is to say the quotient of the side lengths, being in the range given above.
  • the aspect ratio results from the lengths of the axes of symmetry.
  • the filament can also have a triangular basic shape that is not isosceles.
  • the mean value of the two dimensions used for the calculation is used in each case.
  • the filament width is the axis of symmetry of the filament with the largest dimension and the thickness is defined as the axis of symmetry of the filament with the smallest dimension.
  • the filaments to be used according to the invention are asymmetrical and therefore always have a greater width than thickness, which is expressed in an aspect ratio not equal to 1.
  • the filament comprises at least one polymeric material, the polymeric material changing from a solid to a liquid or plastic state with the application of thermal energy.
  • Suitable polymeric base materials are, for example, thermoplastic polymers. These can be homopolymers, alternating copolymers, statistical copolymers, block copolymers or elastomer alloys.
  • the polymer is a polyurethane, a rubber, or a polycarbonate.
  • the rubber can be the base material and can be used before curing or vulcanization.
  • rubbers are the vulcanizates of natural and synthetic rubbers.
  • the polymer can be a thermoplastic polyurethane elastomer.
  • the elastomer is a thermoplastic polyurethane elastomer which can be obtained from the reaction of a polyisocyanate component and a polyol component, the polyol component comprising a polyester polyol which has a pour point (ASTM D5985: 2014) of> 25 ° C.
  • diols in the molecular weight range from> 62 to ⁇ 600 g / mol can furthermore be used as chain extenders in the reaction to give this polyurethane.
  • 4,4 '-MDI or a mixture containing IPDI and HDI as the polyisocyanate component are preferred.
  • Preferred pour points (no flow point) for this polyester polyol are> 35 ° C, more preferably> 35 ° C to ⁇ 55 ° C.
  • a measuring vessel is set with the sample in a slow rotation (0.1 rev / min).
  • a flexibly mounted measuring head dips into the sample and when the pour point is reached the sudden increase in viscosity moves it away from its position, the resulting tilting movement triggers a sensor.
  • polyester polyols which can have such a pour point are reaction products of phthalic acid, phthalic anhydride or symmetrical a, co-C4 to C10 dicarboxylic acids with one or more C2 to C10 diols. They preferably have a number average molecular weight Mn of> 400 g / mol to ⁇ 6000 g / mol.
  • Suitable diols are in particular monoethylene glycol, 1, 4-butanediol, 1, 6-hexanediol and neopentyl glycol.
  • polyester polyols are given below with their acid and diol components: adipic acid + monoethylene glycol; Adipic acid + monoethylene glycol + 1,4-butanediol; Adipic acid + 1,4-butanediol; Adipic acid + 1,6-hexanediol + neopentyl glycol; Adipic acid + 1, 6-hexanediol; Adipic acid + 1,4-butanediol + 1,6-hexanediol; Phthalic acid (anhydride) +
  • Preferred polyurethanes are obtained from a mixture containing IPDI and HDI as the polyisocyanate component and a polyol component containing a preferred polyester polyol mentioned above.
  • the combination of a mixture comprising IPDI and HDI as the polyisocyanate component with a polyester polyol composed of adipic acid + 1, 4-butanediol + 1,6-hexanediol is particularly preferred to form the polyurethanes.
  • polyester polyols have an OH number (DIN 53240: 2007) of> 25 to ⁇ 170 mg KOH / g and / or a viscosity (75 ° C, DIN 51550) of> 50 to ⁇ 5000 mPas.
  • An example is a polyurethane which is obtainable from the reaction of a polyisocyanate component and a polyol component, the polyisocyanate component comprising an HDI and IPDI and the polyol component comprising a polyester polyol which comprises the reaction of a reaction mixture comprising adipic acid and 1,6-hexanediol and 1,4-butanediol is available with a molar ratio of these diols of> 1: 4 to ⁇ 4: 1 and which has a number average molecular weight Mn (GPC, against polystyrene standards) of> 4000 g / mol to ⁇ 6000 g / mol.
  • Mn number average molecular weight
  • Such a polyurethane can have an amount of complex viscosity
  • Suitable polyurethanes are:
  • polyester polyurethanes with terminal hydroxyl groups as described in EP 019 294 6 Al, produced by reacting a) polyester diols with a molecular weight of more than 600 g / mol and optionally b) diols with a molecular weight in the range from 62 to 600 g / mol as chain extenders with c) aliphatic diisocyanates while maintaining an equivalent ratio of hydroxyl groups of components a) and b) to isocyanate groups of component c ) from 1: 0.9 to 1: 0.999, component a) comprising at least 80% by weight of polyester diols of the molecular weight range 4000 to 6000 based on (i) adipic acid and (ii) mixtures of 1,4-dihydroxybutane and 1,6-dihydroxyhexane in the molar ratio of the diols from 4: 1 to 1: 4.
  • polyacrylic rubber ACM
  • SBR styrene-butadiene rubber
  • SI polysiloxane
  • VMQ vinyl methyl silicone
  • NR nitrile rubber
  • HNBR hydrogenated nitrile rubber
  • XNBR carboxylated Nitrile rubber
  • XHNBR carboxylated hydrogenated nitrile rubber
  • EPDM polychloroprene rubber
  • Vamac fluorinated rubber
  • FKM isobutylene rubber
  • IIR polybutadiene rubber
  • BR polybutadiene rubber
  • the rubbers in the uncrosslinked, uncured, uncured state are brought into the desired shape by means of an additive manufacturing process and cured, crosslinked or vulcanized only in a subsequent process step, usually by temperature storage.
  • the filament is fed while melting to a print head according to the invention.
  • the filament can be fed to the print head, for example, via a transport mechanism, which pushes the filament piece by piece from a transport or storage roll to the print head. On the way from the roll to the print head or on the print head itself, the filament is then converted from a solid to at least a plastic or liquid state with the application of thermal energy.
  • the liquefied or plasticized mass can be immediately extruded from the die gap / printhead.
  • the melted polymeric material can be temporarily stored in a collecting container in front of the print head.
  • the material feed and the volume flow can be decoupled from the material volume flow of the filament.
  • the nozzle gap can expediently be configured symmetrically, the two of the axes of symmetry defining the width and the thickness of the nozzle gap.
  • Rectangular nozzle gaps result in a different length and width of the nozzle gap.
  • the length and the width of the nozzle gap are the same. The latter also applies to a round nozzle gap.
  • the length and width are defined as the longest and the shortest dimension of the gap.
  • the geometry of the nozzle gap can be square or round.
  • step c) the melted filament is discharged one or more times in layers through the nozzle opening in order to obtain the shaped body.
  • the molten polymer is applied one or more times from the filament to a substrate or to a polymer that has already been discharged and solidified again.
  • the corresponding dimensions of the nozzle opening and of the filament differ in the width X and / or the thickness Y by> 5%, preferably by> 10%, particularly preferably by> 25%, wherein they preferably do not differ differ more than 95%.
  • the dimensions of the nozzle gap are matched to the dimensions of the filament. Without being bound by theory, this can be attributed to better melting behavior and more uniform shear stress on the polymer in the die gap.
  • the corresponding dimensions are in each case the longest and the shortest axis of the filament and the nozzle gap.
  • the nozzle opening can be, for example, 1 cm wide and 0.5 mm thick.
  • the comparison of the dimensions results from the comparison of the gap dimension with the longest dimension to the filament dimension with the longest dimension.
  • the dimensions of the filament that has not yet been melted are considered. Structures and / or material which have a smaller or a larger dimension than the filament itself can thus be extruded through the different nozzle dimensions.
  • the corresponding dimensions of the nozzle opening and of the filament differ in width X and / or thickness Y by a maximum of 95%.
  • the thickness Y of the nozzle opening is
  • the nozzle gap is chosen to be smaller in comparison to the filament used. Due to the changed dimensions compared to the filament, a better alignment of the polymer chains can be achieved, which is reflected in the structure of the molded body. For example, molded articles with a strong preferred direction of the mechanical properties of the deposited layers can be obtained. Further preferred ratios can be> 20% and ⁇ 90%, further preferably> 40% and ⁇ 70%.
  • the width X of the nozzle opening is> 5% and ⁇ 90% of the filament width.
  • the width of the nozzle opening can also have a significant influence on the quality of the molded body produced. This is surprising since the dimensions of the width of the nozzle gap are usually significantly larger than the thickness of the nozzle gap. In this respect it would be expected that the extrusion result is independent of the die gap width.
  • a reduced width of the nozzle gap compared to the filament can contribute to an improvement in the molded body.
  • Further preferred ratios between width X and filament width can be> 10% and ⁇ 80%, preferably> 20% and ⁇ 70%.
  • both the width X and the thickness Y of the nozzle opening are> 20% and ⁇ 80% of the filament thickness.
  • the nozzle gap is chosen to be smaller overall compared to the dimensions of the filament. Taking into account the thermally induced volume change due to the melting, suitable shear forces can be obtained with these relations, which can contribute to preferred mechanical properties of the extruded molded body.
  • the filament has a width of
  • filaments can provide a sufficiently high material volume flow, which leads to a preferably high production speed. The amounts of material can be melted very quickly and the result is a homogeneously plasticized polymer in which the thermal history of the individual volume elements is the same.
  • the ratio is within the scope of a further preferred embodiment of the method between the aspect ratio of the filament A F u ament and the aspect ratio of the nozzle opening A Ause (A FUament / A nozzle )> 5 and ⁇ 50.
  • the quotient of the aspect ratio of filament and nozzle gap within of the range specified above. This can contribute to preferred material preparation and uniform shear stress in the extrusion process.
  • the polymeric material of the filament comprises a thermoplastic polymer selected from the group consisting of thermoplastics with a melting temperature> 35 ° C. and ⁇ 300 ° C. or mixtures of at least two of them.
  • Thermoplastics with a melting temperature in the specified temperature range show a change in volume during melting, which, in combination with the aspect ratios considered here, leads to particularly mechanically stable 3D-printed molded articles.
  • thermoplastics with a Tg> 80 ° C and or an MVR at 50 ° C above the softening temperature (Tg or melting point in the presence of a melting point) of ⁇ 100 cm 2/10 min at a weight of 2.16 kg.
  • Preferred materials are therefore in particular those which are characterized as extrusion or film types in thermoplastic processing, since they particularly benefit from the larger heat transfer surface of the filaments with a high aspect ratio and the conveying force and the higher shear in the combination of film feed and extrusion heads according to the invention.
  • a significantly improved processing and higher extrusion speeds can be achieved via the higher heat energy that can be added and the higher shear.
  • the polymeric material of the filament comprises a thermoplastic polyurethane, a rubber or a polycarbonate.
  • the polyurethane is preferably a thermoplastic polyurethane which can be obtained from the reaction of a polyisocyanate component and a polyol component, the polyol component comprising a polyester polyol which has a pour point (ASTM D5985: 2014) of> 25 ° C.
  • the combination of a filament comprising such TPU with a slit-shaped print head nozzle is particularly preferred, the width of the print head nozzle corresponding to the width of the filament.
  • the filament has at least two layers, the at least two layers preferably having at least one inner pressure film and one outer protective film, the outer protective film preferably not being melted.
  • Filaments which have reactive polymers can also be processed by means of the method according to the invention.
  • the polymers of these Filaments react with environmental variables such as air humidity or oxygen.
  • These filaments can be protected by a protective film that is not melted on.
  • very fast 3D printing processes can be realized synergistically, so that materials can be printed that would not be printable without protective film and with normal round filaments .
  • isocyanate-functional or silane-functional moisture-curing reactive systems can be processed, or thermoplastics with low Tg, which stick to the roll using the prior art process and can no longer be unwound.
  • thermoplastics with low Tg which stick to the roll using the prior art process and can no longer be unwound.
  • Other possible uses are multi-material filaments consisting of 2 or more layers, which can be both co-extruded and laminated.
  • Multi-layer films - preferably co-extruded multi-layer films - can also be processed.
  • the filament also contains reinforcing fibers.
  • the reinforcing fibers are preferably continuous fibers which are aligned along the longitudinal direction of the filament. Suitable fiber contents are, for example,> 5% by weight, particularly preferably> 10% by weight and very particularly preferably> 15% by weight, the fibers having a fiber length of preferably at least 1 mm, particularly preferably at least 1.5 mm, very particularly preferably have at least 2 mm.
  • it can be a continuous fiber, as used, for example, in so-called organic sheets or surface-structured films. The latter can be promoted better because there is better frictional resistance.
  • the shear of the long fiber-reinforced filaments in the print head is significantly more uniform, which can contribute to better alignment of the fibers in the print body.
  • long fibers can advantageously be processed efficiently and in a controlled manner.
  • two or more different filaments are fed to the printhead at the same time. Due to the large surface area, different filaments can be melted reproducibly within a short period of time, so that more than one filament can be processed at the same time.
  • the different filaments can be the same or different materials and the different layers can have the same or different properties such as thicknesses or colors. There may also be materials in the filaments which react with one another, with or without exposure to heat or through the entry of oxygen or moisture. In this way, two or more reactive substances can be used simultaneously in different Filaments are fed to the print head and react with each other before or in the print head. It is thus possible to produce “in-situ” connections which, for example, are not stable in storage, for example in the form of PUs “synthesized” shortly before or in the nozzle.
  • gradient materials can also be printed out, the composition of which varies as a function of time.
  • 3D-printed workpieces can be produced which have a defined material gradient.
  • mechanically sensitive areas of the printed workpiece can be specifically reinforced or the optical properties can be specifically controlled by filaments with different color compositions.
  • the latter can also be achieved, for example, by feeding an at least two-layer asymmetrical filament. Due to the larger surface area, both sides of the filament can be heated very precisely at the same or different temperatures.
  • the connections in the different filament layers are preferably mobilized by the heating process and a controlled chemical reaction can take place between the connections of the different filament layers.
  • the heating temperature can also be controlled very precisely as a function of the layer in the layer composite.
  • two different foils are processed as a combined filament in the form of a layer composite.
  • the different layers can be mixed with one another in the extruder or, if necessary, also react and thus form a new compound, for example a new polymer.
  • a new polymer for example, by transesterification from two different esters or carbonates, by re-urethanization from two different polyurethanes, allophanatization by reaction of an alcohol with a uretdione, ionic crosslinking by reaction of a thermoplastic containing polyvalent metal salts (for example ZnO or Al sulfate) with a carboxyl-containing polymer or reaction of one Isocyanate-containing polymer with an alcohol-containing polymer.
  • This can significantly increase the flexibility of 3D printing as a whole and benefits in particular from the uniform heating of the asymmetrical filaments.
  • the at least one filament comprises thermoplastic polyurethane and the filament has a Shore A hardness according to DIN ISO 7619-1: 2012 of> 5 and ⁇ 80.
  • Shore A hardness according to DIN ISO 7619-1: 2012 of> 5 and ⁇ 80.
  • the range of hardness of the filament is preferably in a range from> 20 to ⁇ 75, furthermore preferably> 30 and ⁇ 65.
  • filaments of different hardness can also be co-extruded with one another and optionally mixed.
  • the configuration of the 3D printer according to the invention By means of the configuration of the 3D printer according to the invention, very fast printing processes can be realized, in particular also more homogeneous, printed shaped bodies are available.
  • the discharge can be carried out by multiple parallel or arbitrarily arranged individually switchable nozzles of the printer. It is also possible for the melted filament material to be discharged through size-variable nozzles, for example with a variable width.
  • a cutter function can be integrated in the print head or in / in front of the nozzle, which enables the processing and cutting of long fiber-reinforced filaments.
  • a combination with modified nozzle geometries is also possible, for example multiple nozzles, slot nozzles, variable nozzles for more efficient application of thermoplastics in 3D and 2D printing.
  • FIG. 1 a printhead according to the invention
  • FIG. 2 shows a possible embodiment of the filaments that can be used according to the invention
  • FIG. 3A and 3 B further refinements of filaments according to the invention.
  • FIG. 4 the definition of the feed angle of a filament according to the invention to a pair of rollers
  • FIG. 5 different nozzle shapes for extrusion of the filaments that can be used according to the invention.
  • FIG. 1 shows a print head 100 according to the invention for producing 3-dimensional shaped bodies in a 3D printer with a feed unit 300 for a filament 200, a fusing unit 400 for fusing the filament 200 and a printhead nozzle 500.
  • the filament 200 is supplied by the feed unit 300, which here is designed as a pair of rollers, conveyed and melted in the melting unit 400, which can be operated electrically, for example.
  • the melted filament strand 210 exits the printhead via the printhead nozzle 500.
  • the feed unit 300 and the reflow unit 400 are set up to process an asymmetrical filament 200 with an aspect ratio of> 1.5 and ⁇ 1000, which includes in particular the conveying and the melting. Examples of filament cross sections are given in the following FIGS. 2 and 3A to 3C.
  • a cooling unit 600 is also arranged between the feed unit 300 and the melting unit 400, through which the filament 200 is guided to the melting unit 400.
  • the dimensions of the filament to be processed can also determine dimensions in printhead 100.
  • the through opening in the cooling unit 600, through which the filament 200 is guided to the melting unit 400, can have the same cross section as the filament 200 itself. Cross-sectional areas of the through opening in the cooling unit 600 are also conceivable, which correspond to the cross section of the filament plus at most 50%, plus at most 30% or plus at most 15%.
  • the feed unit 300 can be heatable or coolable. To process a large number of polymers and to implement a very fast production process, it has proven to be advantageous to feed the filament to the extrusion die at a temperature. On the one hand, the feed unit 300 can be cooled when processing filaments from polymers with very low T g in order to avoid buildup.
  • the print head nozzle can be set up to be opened and closed during the 3D printing process on the instruction of a control unit.
  • the reflow unit 400 may have multiple heat sources.
  • the sequential heating of the filament 200 by means of several heat sources can contribute to a particularly uniform and gentle melting of the filament. Temperature peaks are avoided and the period in which the filament is completely melted can be kept particularly short. The latter can counteract unwanted, thermally induced degradation processes of the melted filament.
  • the printed filament 210 is at least temporarily decoupled from the entry volume of the supplied filament via a temperature-controlled reservoir arranged in front of the print head nozzle 500 and / or a controllable material outlet for the melted filament material.
  • the cooling unit 600 is designed as a channel provided with cooling fins.
  • the distance in the cooling unit 600 through which the filament 200 is guided to the melting unit 400 is longer than the width of the filament 200.
  • the distance is> 1.5 to ⁇ 10 times longer than the width of the filament 200.
  • the cooling unit 600 and the melting unit 400 are not connected to one another over the full area.
  • the thermal separation is effected by a circumferential gap 700.
  • a passage for guiding the filament 200 which is preferably formed by a thermally low-conductive, high-melting ceramic or polymeric material.
  • the passage can be formed by a thin metallic guide layer, so that the heat transfer from the heating element to the cooling element is as low as possible.
  • the height of the passage is preferably smaller than the width of the filament.
  • the width of the print head nozzle 500 is> 10% to ⁇ 95% of the width of the filament 200 and / or the thickness of the print head nozzle 500 is> 10% to ⁇ 95% of the thickness of the filament 200.
  • the filament 200 has a width of> 500 ⁇ m to ⁇ 50 mm and / or the filament has a thickness of> 20 ⁇ m to ⁇ 5 mm.
  • Preferred widths are> 1 mm to ⁇ 30 mm and preferred thicknesses are from> 50 pm to ⁇ 5 mm.
  • the printhead according to the invention can be set up to process a plurality of filaments.
  • mixtures of thermoplastics can be created directly in the heating head.
  • the composition of the mixtures can be influenced via different feed rates of the filaments to the melting unit.
  • the conveyance of the filaments can be supported by baffles and differently dimensioned melting zones can be constructed. In this way, material mixtures with different temperatures and / or thermal histories can be extruded in a targeted manner.
  • an asymmetrical filament with the aspect ratio provided according to the invention can be bent in the form of a flat band in the reflow unit and guided along the edges of the reflow unit.
  • the melted or plasticized mass of the filament then converges in or just before the print head nozzle and is extruded. If a further material is melted in the interior of the melting unit, for example in the central axis of the melting unit and added, material mixtures can be printed out in which a material is protected or encapsulated by another material.
  • FIG. 2 schematically shows a possible geometry of a filament 200 with a aspect ratio according to the invention.
  • a rectangular filament 2 with a filament width 8 and a filament thickness 7 is shown.
  • the thickness 7 is significantly smaller than the filament width 8. The result is an easily meltable filament 2 with a large surface area.
  • FIG. 3A schematically shows a possible geometry of a filament 200 with an aspect ratio according to the invention.
  • An oval filament 2 with a filament width 8 and a filament thickness 7 is shown.
  • the thickness 7 is significantly smaller than the filament width 8. The result is an easily meltable filament 2 with a large surface area.
  • FIG. 3B schematically shows a possible geometry of a filament 200 with an aspect ratio according to the invention.
  • a rectangular filament 2 is shown with rounded corners, a filament width 8 and a filament thickness 7.
  • the maximum dimensions of the rounded rectangle 2 are considered.
  • the thickness 7 is significantly smaller than the filament width 8. The result is an easily meltable filament 2 with a large surface area.
  • the FIG. 4 schematically shows the determination of the feed angle of the filament 200 to feed rolls 3.
  • the angle is formed by the center line 9, which runs perpendicular to the roll pair axis and centrally to the roll gap.
  • the other leg of the angle is formed by the tangent 10 to the supplied filament 2.
  • This angle can be set, for example, by further mechanical guide elements (not shown).
  • the angled feed of the filament 2 means that significantly more constant feed speeds of the filament 2 to the print head 1 can be maintained.
  • the feed unit can comprise two rollers and a guide for the filaments, the guide being set up to feed filaments into the roller gap at an angle of> 5 ° and ⁇ 85 °. Due to the non-symmetrical feeding of the filaments into the nip, in contrast to a straight introduction, a significantly more uniform material volume flow for asymmetrically shaped filaments can be achieved. Without being bound by theory, the more even volume flow can result from the fact that the filament bends somewhat due to the angled feed. The result is a live material reservoir, which can compensate for slight fluctuations in the conveyor unit, for example the pair of rollers.
  • the angle results from a vector parallel to the axis of symmetry of the pair of rollers and passing through the center of the nip and a filament vector which touches the filament in front of the nip.
  • the angle is shown in FIG. 4 defined. This angular range has proven to be particularly suitable for building up a sufficiently pre-tensioned filament.
  • FIG. 5A-C show different printhead nozzles for processing the invention provided filaments 2.
  • a symmetrical printhead nozzle is shown in which the nozzle gap has the same width and thickness. Round or square nozzle gap geometries are therefore recorded in this embodiment.
  • FIG. 5B schematically shows a cross section of an asymmetrical nozzle gap of a slot nozzle.
  • the slot nozzle has only a small thickness and a larger width.
  • FIG. 5C shows a multi-extrusion die in which several die heads are installed. Material can be extruded through each individual nozzle head.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)

Abstract

L'invention concerne un tête d'impression (100) servant à fabriquer des corps façonnés tridimensionnels dans une imprimante 3D, présentant au moins une unité d'alimentation (300) pour un filament (200), une unité de fusion (400) servant à faire fondre le filament (200), et une buse de tête d'impression (500). Cette tête d'impression est caractérisée en ce que l'unité d'alimentation (300) et l'unité de fusion (400) sont conçues pour traiter un filament (200) asymétrique présentant un facteur de forme ≥ 1,5 et ≤ 1000, et en ce qu'une unité de refroidissement (600), à travers laquelle le filament (200) est guidé vers l'unité de fusion (400), est disposée entre l'unité d'alimentation (300) et l'unité de fusion (400).
PCT/EP2019/082525 2018-11-29 2019-11-26 Fabrication additive de corps façonnés tridimensionnels au moyen de filaments à facteur de forme élevé WO2020109280A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP18209136 2018-11-29
EP18209136.3 2018-11-29

Publications (1)

Publication Number Publication Date
WO2020109280A1 true WO2020109280A1 (fr) 2020-06-04

Family

ID=64559531

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2019/082525 WO2020109280A1 (fr) 2018-11-29 2019-11-26 Fabrication additive de corps façonnés tridimensionnels au moyen de filaments à facteur de forme élevé

Country Status (1)

Country Link
WO (1) WO2020109280A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114734634A (zh) * 2022-04-19 2022-07-12 杭州正向增材制造技术有限公司 熔融挤出增材制造喷头和增材制造设备

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0192946A1 (fr) 1985-01-25 1986-09-03 Bayer Ag Polyesterpolyuréthanes contenant des groupes hydroxy terminaux et leur utilisation comme adhésif ou pour la préparation d'adhésifs
US20110076496A1 (en) * 2009-09-30 2011-03-31 Stratasys, Inc. Non-cylindrical filaments for use in extrusion-based digital manufacturing systems
WO2016140420A1 (fr) * 2015-03-04 2016-09-09 엘지전자 주식회사 Imprimante 3d
WO2016170030A1 (fr) 2015-04-21 2016-10-27 Covestro Deutschland Ag Procédé de fabrication d'objets en 3d
WO2018158239A1 (fr) 2017-02-28 2018-09-07 Covestro Deutschland Ag Tête d'impression, procédé et système pour l'impression 3d à une vitesse de sortie variable

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0192946A1 (fr) 1985-01-25 1986-09-03 Bayer Ag Polyesterpolyuréthanes contenant des groupes hydroxy terminaux et leur utilisation comme adhésif ou pour la préparation d'adhésifs
US20110076496A1 (en) * 2009-09-30 2011-03-31 Stratasys, Inc. Non-cylindrical filaments for use in extrusion-based digital manufacturing systems
EP2483060B1 (fr) 2009-09-30 2017-03-08 Stratasys, Inc. Système de fabrication digital par extrusion avec un filament en forme de ruban
WO2016140420A1 (fr) * 2015-03-04 2016-09-09 엘지전자 주식회사 Imprimante 3d
WO2016170030A1 (fr) 2015-04-21 2016-10-27 Covestro Deutschland Ag Procédé de fabrication d'objets en 3d
WO2018158239A1 (fr) 2017-02-28 2018-09-07 Covestro Deutschland Ag Tête d'impression, procédé et système pour l'impression 3d à une vitesse de sortie variable

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114734634A (zh) * 2022-04-19 2022-07-12 杭州正向增材制造技术有限公司 熔融挤出增材制造喷头和增材制造设备
CN114734634B (zh) * 2022-04-19 2024-04-09 浙江正向增材制造有限公司 熔融挤出增材制造喷头和增材制造设备

Similar Documents

Publication Publication Date Title
EP0155552B1 (fr) Procédé de fabrication de matériau comprenant des éléments sensibles aux efforts de cisaillement
EP2739460A2 (fr) Procédé et dispositif de fabrication d'un objet tridimensionnel comprenant l'apport de fibres
EP3645249B1 (fr) Procédé 3d faisant appel à la commande en fonction du chemin d'impression
EP3829849B1 (fr) Procédé et dispositif de fabrication d'un composant plastique renforcé par des fibres
DE102016213439A1 (de) Extruder für 3D-Drucker mit variablem Materialdurchsatz
DE102017105231A1 (de) Verfahren und Vorrichtung zum computergestützten Erzeugen 3-dimensionaler Schaumstrukturen aus einem Gemisch aus einem Polymerwerkstoff und einem Treibmittel
EP2860020B1 (fr) Procédé et dispositif d'un objet tridimensionnel et objet correspondant
EP2243618B1 (fr) Procédé de fabrication d'un film thermoplastique doté d'une surface structurée tridimensionnelle
EP3126114A1 (fr) Pièce hybride métal-plastique et procédé de production
AT520032A1 (de) Formgebungsmaschine zum Herstellen von faserverstärkten Formteilen
DE102019007939B4 (de) Verfahren zur Herstellung von Polymer-Formteilen aus thermoplastischen Polymeren mitFormgedächtniseigenschaften und/oder mit thermoresponsiven Eigenschaften, insbesondere mittels 4D-Druck, sowie solchermaßen hergestelltes Polymer-Formteil
WO2020109280A1 (fr) Fabrication additive de corps façonnés tridimensionnels au moyen de filaments à facteur de forme élevé
DE102012012471A1 (de) Verfahren zur pulverbettbasierten generativen Fertigung eines Körpers
DE102018102731B4 (de) Vorrichtung und Verfahren zur additiven Herstellung eines Werkstücks oder Bauteils aus verstärkten Kunststoffen
WO2023247121A1 (fr) Filament d'impression 3d renforcé par des fibres sans fin et son procédé de production
EP1235676A1 (fr) Extrudeuse servant au traitement de melanges de caoutchouc
WO2021023389A1 (fr) Procédé et appareil d'extrusion destinés à l'extrusion de matière plastique renforcée par des fibres pour la fabrication additive d'un élément
EP3126449B1 (fr) Composition polymère, demi-produit composite renforcé de fibres et procédé de production
EP3959062B1 (fr) Procédé de fabrication additive permettant de produire un corps façonné à partir d'un élastomère
DE102022126382A1 (de) Lagenförmiges Verbundmaterial mit Formgedächtnispolymeren und Verfahren zu seiner Herstellung
DE2051568A1 (en) Molten plastic extrusion - with pressure - controlled recycle system
WO2023078750A1 (fr) Procédé de production d'au moins un composant
EP3095574A1 (fr) Procede et dispositif pour la fabrication de granules expanses, et granules ainsi produits
DE102016200530B4 (de) Verfahren zur Herstellung eines faserverstärkten Kunststoffbauteils
DE102014003968A1 (de) Verfahren zum Herstellen eines Kunststoffspritzgussteiles und Kunststoffspritzgussteil

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19806266

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19806266

Country of ref document: EP

Kind code of ref document: A1