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EP4598730A1 - Extrusion head for the additive manufacture of a moulded body - Google Patents

Extrusion head for the additive manufacture of a moulded body

Info

Publication number
EP4598730A1
EP4598730A1 EP23789490.2A EP23789490A EP4598730A1 EP 4598730 A1 EP4598730 A1 EP 4598730A1 EP 23789490 A EP23789490 A EP 23789490A EP 4598730 A1 EP4598730 A1 EP 4598730A1
Authority
EP
European Patent Office
Prior art keywords
tubular body
carrier
extrusion
induction coil
guide flange
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
EP23789490.2A
Other languages
German (de)
French (fr)
Inventor
Frank Jakob
Stefan SPOR
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plasmics GmbH
Original Assignee
Plasmics GmbH
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 Plasmics GmbH filed Critical Plasmics GmbH
Publication of EP4598730A1 publication Critical patent/EP4598730A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
    • H05B6/108—Induction heating apparatus, other than furnaces, for specific applications using a susceptor for heating a fluid
    • 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
    • B29C64/295—Heating elements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
    • H05B6/107—Induction heating apparatus, other than furnaces, for specific applications using a susceptor for continuous movement of material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/14—Tools, e.g. nozzles, rollers, calenders
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/36—Coil arrangements
    • H05B6/44—Coil arrangements having more than one coil or coil segment
    • 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
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • B29C2035/0811—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using induction
    • 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

Definitions

  • the invention relates to an extrusion head for the additive manufacturing of a molded body with a tubular body made of a ferromagnetic material which opens into an extrusion nozzle and is held in a carrier on the feed side, forming an extrusion channel, and with at least one induction coil enclosing the tubular body between the carrier and the extrusion nozzle.
  • the inductively heated tubular body can thus give off its heat to the thermoplastic material, which can be advantageously melted during its conveyance through the extrusion channel in a manner determined with regard to the temperature profile in order to be discharged as a melt strand from the extrusion nozzle closing the extrusion channel.
  • the ferromagnetic tubular bodies can have radially protruding spacer rings on both end faces (WO 2016/102 669 A1).
  • the magnetic field induced in the tubular body forms a stray field in the area of the support that holds the tubular body, which impairs the heating performance of the induction coil. If the support forms a conventional aluminum or copper-based heat sink through which the thermoplastic material strand is fed to the tubular body, the additional problem arises that the magnetic stray field emerging from the inlet-side end of the tubular body held by the heat sink induces eddy currents in the heat sink, which undesirably heat the heat sink.
  • the invention solves the problem in that the tubular body has a guide flange for the induced magnetic field, which is arranged in the axial direction between the induction coil and the carrier and projects radially outwards.
  • the radially outwardly projecting guide flange results in a branching of the magnetic circuit with the effect that a significant part of the magnetic field lines bundled in the guide flange are diverted from the ferromagnetic tubular body, so that the residual magnetic field in the connection area of the tubular body to the carrier causes a comparatively small stray field, so that the inductive heating of the tubular body is improved.
  • this also means that the eddy currents induced in the metallic heat sink by the stray magnetic field can be reduced to a level that is insignificant for the temperature profile in the heat sink.
  • the section of the pipe body protruding axially over the guide flange towards the support can have a smaller wall thickness than the section of the pipe body enclosed by the induction coil.
  • the associated bundling of the field lines can also be used to guide the magnetic circuit in the area of the extrusion nozzle in order to specify special induction conditions and thus ensure a predetermined temperature profile for the melt strand.
  • Fig. 1 shows an extrusion head according to the invention in a schematic longitudinal section in the area of the induction heating
  • Fig. 2 is a representation corresponding to Fig. 1 of an embodiment variant of an extrusion head according to the invention.
  • thermoplastic material strand which is applied in layers as a melt for the additive manufacture of a molded body, is fed through a conveyor channel 1 of a carrier 2 to an extrusion channel 3 which continues the conveyor channel 1 and opens into an extrusion nozzle 4 in order to be melted along the extrusion channel 3 and discharged from the extrusion nozzle 4 as a melt strand.
  • an inductive heating device which comprises a tubular body 5 made of a ferromagnetic material forming the extrusion channel 3 and at least one induction coil 6 surrounding the tubular body 5 at a radial distance.
  • the carrier 2 receiving the tubular body 5 preferably forms a cooling body based on aluminum or copper, into which the tubular body 5 is screwed, for example.
  • the tubular body 5 has a radially outwardly projecting guide flange 7 for the induced magnetic field in the axial direction between the induction coil 6 and the carrier 2, which guide flange diverts a considerable part of the magnetic field from the tubular body 5, so that the residual field in the area of the section 8 of the tubular body 5 between the guide flange 7 and the carrier 2 causes only a comparatively small stray field, which means that on the one hand the effect of the inductive heating can be improved and on the other hand the eddy currents that are induced in the carrier 2 designed as a metallic heat sink are negligible.
  • the guide flange 7 of the tubular body 5 can advantageously serve as a holder for the preferably ceramic coil carrier 9 in order to achieve a to secure an annular gap 10 between the tubular body 5 and the coil carrier 9 which hinders heat transfer.
  • care must be taken to ensure that the position of the guide flange 7 relative to the induction coil 6 is selected in such a way that the magnetic partial circle caused by the guide flange 7 is formed in a way which is advantageous for the field line course.
  • the tubular body 5 according to Fig. 2 has, in addition to the guide flange 7 which acts as a magnetic shield for the carrier 2, a further guide flange 11 in the axial direction between the induction coil 6 and the extrusion nozzle 4, which also influences the course of the magnetic field lines and can therefore help to adjust the magnetic circuit, in particular with regard to the requirements for the temperature profile of the melt strand in the area of the extrusion nozzle 4.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

A description is given of an extrusion head for the additive manufacture of a moulded body comprising a tubular body (5) of a ferromagnetic material, which opens out in an extrusion die (4), on the feed side is held in a carrier (2), and forms an extrusion channel (3), and also comprising at least one induction coil (6), which encloses the tubular body (5) between the carrier (2) and the extrusion die (4). To make advantageous melting conditions possible, it is proposed that the tubular body (5) has for the induced magnetic field a guide flange (7), which is arranged between the induction coil (6) and the carrier (2) in the axial direction and protrudes radially outwards.

Description

für die additive Fertiqunq eines for the additive manufacturing of a

Technisches Gebiet Technical area

Die Erfindung bezieht sich auf einen Extrusionskopf für die additive Fertigung eines Formkörpers mit einem in einer Extrusionsdüse mündenden, zuführseitig in einem Träger gehaltenen, einen Extrusionskanal bildenden Rohrkörper aus einem ferromagnetischen Werkstoff und mit wenigstens einer den Rohrkörper zwischen dem Träger und der Extrusionsdüse umschließenden Induktionsspule. The invention relates to an extrusion head for the additive manufacturing of a molded body with a tubular body made of a ferromagnetic material which opens into an extrusion nozzle and is held in a carrier on the feed side, forming an extrusion channel, and with at least one induction coil enclosing the tubular body between the carrier and the extrusion nozzle.

Stand der Technik State of the art

Um die für das Aufschmelzen eines in Strangform einem Extrusionskopf zugeführten thermoplastischen Materials benötigte Wärmeenergie vorteilhaft zur Verfügung stellen zu können, ist es bekannt (EP 3 148 293 A1 , WO 2016/102 669 A1 ), anstelle der üblichen elektrischen Widerstandsheizung eine elektrische Induktionsheizung vorzusehen. Zu diesem Zweck sind ein einen Extrusionskanal zum Aufschmelzen des zugeführten thermoplastischen Materials bildender, in einer Extrusionsdüse zum Austragen des Schmelzestrangs mündender Rohrkörper aus einem ferromagnetischen Werkstoff und wenigstens eine Induktionsspule vorgesehen, die den Rohrkörper mit radialem Abstand umschließt. Der induktiv erwärmte Rohrkörper kann somit seine Wärme an das thermoplastische Material abgeben, das während seiner Förderung durch den Extrusionskanal in einer hinsichtlich des Temperaturverlaufs bestimmten Art vorteilhaft aufgeschmolzen werden kann, um als Schmelzestrang aus der den Extrusionskanal abschließenden Extrusionsdüse ausgetragen zu werden. In order to be able to advantageously provide the heat energy required for melting a thermoplastic material fed to an extrusion head in strand form, it is known (EP 3 148 293 A1, WO 2016/102 669 A1) to provide an electrical induction heater instead of the usual electrical resistance heater. For this purpose, a tubular body made of a ferromagnetic material forming an extrusion channel for melting the supplied thermoplastic material and opening into an extrusion nozzle for discharging the melt strand and at least one induction coil are provided which encloses the tubular body at a radial distance. The inductively heated tubular body can thus give off its heat to the thermoplastic material, which can be advantageously melted during its conveyance through the extrusion channel in a manner determined with regard to the temperature profile in order to be discharged as a melt strand from the extrusion nozzle closing the extrusion channel.

Um zwischen den ferromagnetischen Rohrkörpern und einer diese Rohrkörper aufnehmenden, von wenigstens einer Induktionsspule umschlossenen, elektrisch isolierenden Hülse einen Ringspalt vorzusehen, der einen Wärmeübergang zwischen den induktiv erwärmten Rohrkörpern und der diese Rohrkörper aufnehmenden Isolierhülse erschwert, können die ferromagnetischen Rohrkörper an den beiden Stirnseiten radial vorstehende Abstandhalteringe aufweisen (WO 2016/102 669 A1 ). In order to provide an annular gap between the ferromagnetic tubular bodies and an electrically insulating sleeve which accommodates these tubular bodies and is surrounded by at least one induction coil, which allows heat transfer between the inductively heated tubular bodies and the tubular bodies To make it more difficult to insert the insulating sleeve into the ferromagnetic tube, the ferromagnetic tubular bodies can have radially protruding spacer rings on both end faces (WO 2016/102 669 A1).

Das im Rohrkörper induzierte Magnetfeld bildet im Bereich des den Rohrkörper aufnehmenden Trägers ein die Heizleistung der Induktionsspule beeinträchtigendes Streufeld. Bildet der Träger in herkömmlicher Weise einen Kühlkörper auf Aluminium- oder Kupferbasis, durch den der thermoplastische Materialstrang dem Rohrkörper zugefördert wird, so ergibt sich das zusätzliche Problem, dass das aus dem vom Kühlkörper aufgenommenen zulaufseitigen Ende des Rohrkörpers austretende magnetische Streufeld im Kühlkörper Wirbelströme induziert, die den Kühlkörper unerwünscht erwärmen. Zur Verbesserung der Induktionswirkung der Induktionsspule ist es zwar bekannt (EP 3 148 293 A1 ) die Induktionsspule außen mit einem Weicheisenzylinder zu umfassen, doch kann damit das Problem der magnetischen Streufelder im Bereich des in einem Träger gehaltenen, zuführseitigen Endes des ferromagnetischen Rohrkörpers nicht gelöst werden. The magnetic field induced in the tubular body forms a stray field in the area of the support that holds the tubular body, which impairs the heating performance of the induction coil. If the support forms a conventional aluminum or copper-based heat sink through which the thermoplastic material strand is fed to the tubular body, the additional problem arises that the magnetic stray field emerging from the inlet-side end of the tubular body held by the heat sink induces eddy currents in the heat sink, which undesirably heat the heat sink. In order to improve the induction effect of the induction coil, it is known (EP 3 148 293 A1) to surround the induction coil on the outside with a soft iron cylinder, but this cannot solve the problem of magnetic stray fields in the area of the feed-side end of the ferromagnetic tubular body held in a support.

Darstellung der Erfindung Description of the invention

Der Erfindung liegt somit die Aufgabe zugrunde, einen Extrusionskopf für die additive Fertigung eines Formkörpers so mit einer induktiven Heizeinrichtung auszustatten, dass unerwünschte Wirkungen von magnetischen Streufeldern im zuführseitigen Bereich der Rohrkörper weitgehend vermieden werden können. The invention is therefore based on the object of equipping an extrusion head for the additive manufacturing of a molded body with an inductive heating device in such a way that undesirable effects of magnetic stray fields in the feed-side area of the tubular body can be largely avoided.

Ausgehend von einem Extrusionskopf der eingangs geschilderten Art löst die Erfindung die gestellte Aufgabe dadurch, dass der Rohrkörper einen in axialer Richtung zwischen der Induktionsspule und dem Träger angeordneten, radial nach außen abstehenden Leitflansch für das induzierte Magnetfeld aufweist. Starting from an extrusion head of the type described above, the invention solves the problem in that the tubular body has a guide flange for the induced magnetic field, which is arranged in the axial direction between the induction coil and the carrier and projects radially outwards.

Durch den radial nach außen abstehenden Leitflansch ergibt sich eine Verzweigung des magnetischen Kreises mit der Wirkung, dass ein erheblicher Teil der im Leitflansch gebündelten magnetischen Feldlinien aus dem ferromagnetischen Rohrkörper austritt, sodass das magnetische Restfeld im Anschlussbereich des Rohrkörpers an den Träger ein vergleichsweise geringes Streufeld bedingt, sodass die induktive Erwärmung des Rohrkörpers verbessert wird. Bei der üblichen Aufnahme des Rohrkörpers in einem Kühlkörper bedeutet dies außerdem, dass die im metallischen Kühlkörper durch das magnetische Streufeld induzierten Wirbelströme auf ein für den Temperaturverlauf im Kühlkörper unerhebliches Maß verringert werden können. The radially outwardly projecting guide flange results in a branching of the magnetic circuit with the effect that a significant part of the magnetic field lines bundled in the guide flange are diverted from the ferromagnetic tubular body, so that the residual magnetic field in the connection area of the tubular body to the carrier causes a comparatively small stray field, so that the inductive heating of the tubular body is improved. With the usual housing of the tubular body in a heat sink, this also means that the eddy currents induced in the metallic heat sink by the stray magnetic field can be reduced to a level that is insignificant for the temperature profile in the heat sink.

Um das Restfeld in dem an den Leitflansch anschließenden, zum Träger hin verlaufenden Abschnitt des Rohrkörpers möglichst klein zu halten, kann der axial über den Leitflansch gegen den Träger vorstehende Abschnitt des Rohrkörpers eine kleinere Wanddicke als der von der Induktionsspule umschlossene Abschnitt des Rohrkörpers aufweisen. In order to keep the residual field in the section of the pipe body adjoining the guide flange and running towards the support as small as possible, the section of the pipe body protruding axially over the guide flange towards the support can have a smaller wall thickness than the section of the pipe body enclosed by the induction coil.

Ist der Rohrkörper zwischen der Induktionsspule und der Extrusionsdüse ebenfalls mit einem radial nach außen abstehenden Leitflansch für das induzierte Magnetfeld versehen, so kann durch die damit verbundene Bündelung der Feldlinien auch eine Führung des magnetischen Kreises im Bereich der Extrusionsdüse erreicht werden, um besondere Induktionsverhältnisse vorgeben und damit einen vorbestimmten Temperaturverlauf für den Schmelzestrang sicherstellen zu können. If the pipe body between the induction coil and the extrusion nozzle is also provided with a radially outwardly projecting guide flange for the induced magnetic field, the associated bundling of the field lines can also be used to guide the magnetic circuit in the area of the extrusion nozzle in order to specify special induction conditions and thus ensure a predetermined temperature profile for the melt strand.

Kurze Beschreibung der Erfindung Brief description of the invention

In der Zeichnung ist der Erfindungsgegenstand beispielsweise dargestellt. Es zeigen The drawing shows the subject matter of the invention as an example.

Fig. 1 einen erfindungsgemäßen Extrusionskopf ausschnittsweise im Bereich der Induktionsheizung in einem schematischen Längsschnitt und Fig. 1 shows an extrusion head according to the invention in a schematic longitudinal section in the area of the induction heating and

Fig. 2 eine der Fig. 1 entsprechende Darstellung einer Ausführungsvariante eines erfindungsgemäßen Extrusionskopfs. Fig. 2 is a representation corresponding to Fig. 1 of an embodiment variant of an extrusion head according to the invention.

Weg zur Ausführung der Erfindung In der Zeichnung ist von dem zum Einsatz kommenden Extrusionskopf lediglich der Bereich schematisch dargestellt, der für das Aufschmelzen des zugeführten thermoplastischen Materialstrangs vorgesehen ist. Dieser thermoplastische Materialstrang, der zur additive Fertigung eines Formkörpers als Schmelze schichtweise aufgebracht wird, wird durch einen Förderkanal 1 eines Trägers 2 einem den Förderkanal 1 fortsetzenden Extrusionskanal 3 zugeführt, der in einer Extrusionsdüse 4 mündet, um entlang des Extrusionskanals 3 aufgeschmolzen und als Schmelzestrang aus der Extrusionsdüse 4 ausgetragen zu werden. Way to implement the invention In the drawing, only the area of the extrusion head used is shown schematically which is intended for melting the supplied thermoplastic material strand. This thermoplastic material strand, which is applied in layers as a melt for the additive manufacture of a molded body, is fed through a conveyor channel 1 of a carrier 2 to an extrusion channel 3 which continues the conveyor channel 1 and opens into an extrusion nozzle 4 in order to be melted along the extrusion channel 3 and discharged from the extrusion nozzle 4 as a melt strand.

Zu diesem Zweck ist eine induktive Heizeinrichtung vorgesehen, die einen den Extrusionskanal 3 bildenden Rohrkörper 5 aus einem ferromagnetischen Werkstoff und wenigstens eine den Rohrkörper 5 mit radialem Abstand umschließende Induktionsspule 6 umfasst. Der den Rohrkörper 5 aufnehmende Träger 2 bildet vorzugsweise einen Kühlkörper auf Aluminium- oder Kupferbasis, in den der Rohrkörper 5 beispielsweise eingeschraubt wird. For this purpose, an inductive heating device is provided which comprises a tubular body 5 made of a ferromagnetic material forming the extrusion channel 3 and at least one induction coil 6 surrounding the tubular body 5 at a radial distance. The carrier 2 receiving the tubular body 5 preferably forms a cooling body based on aluminum or copper, into which the tubular body 5 is screwed, for example.

Der Rohrkörper 5 weist in axialer Richtung zwischen der Induktionsspule 6 und dem Träger 2 einen radial nach außen abstehenden Leitflansch 7 für das induzierte Magnetfeld auf, der einen erheblichen Teil des Magnetfeldes aus dem Rohrkörper 5 ableitet, sodass das Restfeld im Bereich des Abschnitts 8 des Rohrkörpers 5 zwischen dem Leitflansch 7 und dem Träger 2 nur ein vergleichsweise geringes Streufeld bedingt, was dazu führt, dass einerseits die Wirkung der induktiven Heizung verbessert werden kann und anderseits die Wirbelströme, die im als metallischer Kühlkörper ausgebildeten Träger 2 induzierten werden, vernachlässigbar sind. The tubular body 5 has a radially outwardly projecting guide flange 7 for the induced magnetic field in the axial direction between the induction coil 6 and the carrier 2, which guide flange diverts a considerable part of the magnetic field from the tubular body 5, so that the residual field in the area of the section 8 of the tubular body 5 between the guide flange 7 and the carrier 2 causes only a comparatively small stray field, which means that on the one hand the effect of the inductive heating can be improved and on the other hand the eddy currents that are induced in the carrier 2 designed as a metallic heat sink are negligible.

Um das magnetische Restfeld klein zu halten, kann der vom Leitflansch 7 gegen den Träger 2 vorstehende Abschnitt 8 des Rohrkörpers 5 eine gegenüber der übrigen Dicke der Wand des Rohrkörpers 5 kleinere Wanddicke aufweisen. In order to keep the residual magnetic field small, the section 8 of the tubular body 5 protruding from the guide flange 7 towards the carrier 2 can have a smaller wall thickness than the remaining thickness of the wall of the tubular body 5.

Wie der Zeichnung entnommen werden kann, kann der Leitflansch 7 des Rohrkörpers 5 vorteilhaft als Halterung des vorzugsweise keramischen Spulenträgers 9 dienen, um ohne zusätzliche Konstruktionsmaßnahmen einen einen Wärmeübergang behindernden Ringspalt 10 zwischen dem Rohrkörper 5 und dem Spulenträger 9 zu sichern. Es muss allerdings darauf geachtet werden, dass die Lage des Leitflansches 7 gegenüber der Induktionsspule 6 so gewählt wird, dass sich ein für den Feldlinienverlauf vorteilhafte Ausbildung des durch den Leitflansch 7 bedingten magnetischen Teilkreises ergibt. As can be seen from the drawing, the guide flange 7 of the tubular body 5 can advantageously serve as a holder for the preferably ceramic coil carrier 9 in order to achieve a to secure an annular gap 10 between the tubular body 5 and the coil carrier 9 which hinders heat transfer. However, care must be taken to ensure that the position of the guide flange 7 relative to the induction coil 6 is selected in such a way that the magnetic partial circle caused by the guide flange 7 is formed in a way which is advantageous for the field line course.

Zum Unterschied zur Ausführungsform nach der Fig. 1 weist der Rohrkörper 5 gemäß der Fig. 2 neben dem im Sinne einer magnetischen Abschirmung des Trägers 2 wirksamen Leitflansch 7 einen weiteren Leitflansch 11 in axialer Richtung zwischen der Induktionsspule 6 und der Extrusionsdüse 4 auf, der ebenfalls Einfluss auf den Verlauf der magnetischen Feldlinien nimmt und daher dazu beitragen kann, den magnetischen Kreis insbesondere hinsichtlich der Anforderungen an den Temperaturverlauf des Schmelzestrangs im Bereich der Extrusionsdüse 4 abzustimmen. In contrast to the embodiment according to Fig. 1, the tubular body 5 according to Fig. 2 has, in addition to the guide flange 7 which acts as a magnetic shield for the carrier 2, a further guide flange 11 in the axial direction between the induction coil 6 and the extrusion nozzle 4, which also influences the course of the magnetic field lines and can therefore help to adjust the magnetic circuit, in particular with regard to the requirements for the temperature profile of the melt strand in the area of the extrusion nozzle 4.

Claims

Patentansprüche Patent claims 1 . Extrusionskopf für die additive Fertigung eines Formkörpers mit einem in einer Extrusionsdüse (4) mündenden, zuführseitig in einem Träger (2) gehaltenen, einen Extrusionskanal (3) bildenden Rohrkörper (5) aus einem ferromagnetischen Werkstoff und mit wenigstens einer den Rohrkörper (5) zwischen dem Träger (2) und der Extrusionsdüse (4) umschließenden Induktionsspule (6), dadurch gekennzeichnet, dass der Rohrkörper (5) einen in axialer Richtung zwischen der Induktionsspule (6) und dem Träger (2) angeordneten, radial nach außen abstehenden Leitflansch (7) für das induzierte Magnetfeld aufweist. 1. Extrusion head for the additive manufacturing of a molded body with a tubular body (5) made of a ferromagnetic material which opens into an extrusion nozzle (4), is held on the feed side in a carrier (2) and forms an extrusion channel (3), and with at least one induction coil (6) enclosing the tubular body (5) between the carrier (2) and the extrusion nozzle (4), characterized in that the tubular body (5) has a guide flange (7) for the induced magnetic field which is arranged in the axial direction between the induction coil (6) and the carrier (2) and projects radially outwards. 2. Extrusionskopf nach Anspruch 1 , dadurch gekennzeichnet, dass der axial über den Leitflansch (7) gegen den Träger (2) vorstehende Abschnitt (8) des Rohrkörpers (5) eine kleinere Wanddicke als der von der Induktionsspule (6) umschlossene Abschnitt des Rohrkörpers (5) aufweist. 2. Extrusion head according to claim 1, characterized in that the section (8) of the tubular body (5) projecting axially beyond the guide flange (7) towards the carrier (2) has a smaller wall thickness than the section of the tubular body (5) enclosed by the induction coil (6). 3. Extrusionskopf nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der Rohrkörper (5) zwischen der Induktionsspule (6) und der Extrusionsdüse (4) einen radial nach außen abstehenden Leitflansch (11 ) für das induzierte Magnetfeld aufweist. 3. Extrusion head according to claim 1 or 2, characterized in that the tubular body (5) has a radially outwardly projecting guide flange (11) for the induced magnetic field between the induction coil (6) and the extrusion nozzle (4).
EP23789490.2A 2022-10-06 2023-10-05 Extrusion head for the additive manufacture of a moulded body Pending EP4598730A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ATA50778/2022A AT526563B1 (en) 2022-10-06 2022-10-06 Extrusion head for the additive manufacturing of a molded body
PCT/AT2023/060347 WO2024073789A1 (en) 2022-10-06 2023-10-05 Extrusion head for the additive manufacture of a moulded body

Publications (1)

Publication Number Publication Date
EP4598730A1 true EP4598730A1 (en) 2025-08-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP23789490.2A Pending EP4598730A1 (en) 2022-10-06 2023-10-05 Extrusion head for the additive manufacture of a moulded body

Country Status (3)

Country Link
EP (1) EP4598730A1 (en)
AT (1) AT526563B1 (en)
WO (1) WO2024073789A1 (en)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL2014044B9 (en) * 2014-12-23 2017-03-29 Bond High Performance 3D Tech B V Deposition print head.
NL2015512B1 (en) * 2015-09-28 2017-04-20 Ultimaker Bv Inductive nozzle heating assembly.
NL2017016B1 (en) * 2016-06-21 2018-01-04 Ultimaker Bv Nozzle for a three dimensional printing apparatus
US20200061896A1 (en) * 2018-08-26 2020-02-27 Khan Khac Tran Induction Heated Extrusion Melter

Also Published As

Publication number Publication date
AT526563A1 (en) 2024-04-15
AT526563B1 (en) 2025-05-15
WO2024073789A1 (en) 2024-04-11

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