DE29709456U1 - Device for welding plastic - Google Patents
Device for welding plasticInfo
- Publication number
- DE29709456U1 DE29709456U1 DE29709456U DE29709456U DE29709456U1 DE 29709456 U1 DE29709456 U1 DE 29709456U1 DE 29709456 U DE29709456 U DE 29709456U DE 29709456 U DE29709456 U DE 29709456U DE 29709456 U1 DE29709456 U1 DE 29709456U1
- Authority
- DE
- Germany
- Prior art keywords
- strip
- tool
- alternating current
- plastic
- transformer
- 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.)
- Expired - Lifetime
Links
- 239000004033 plastic Substances 0.000 title claims description 24
- 229920003023 plastic Polymers 0.000 title claims description 24
- 238000003466 welding Methods 0.000 title claims description 15
- 238000004804 winding Methods 0.000 claims description 21
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 12
- 229910052802 copper Inorganic materials 0.000 claims description 12
- 239000010949 copper Substances 0.000 claims description 12
- 229910001374 Invar Inorganic materials 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 239000002826 coolant Substances 0.000 claims description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052737 gold Inorganic materials 0.000 claims description 2
- 239000010931 gold Substances 0.000 claims description 2
- 230000002500 effect on skin Effects 0.000 description 7
- 239000002985 plastic film Substances 0.000 description 7
- 229920006255 plastic film Polymers 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000012447 hatching Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000036512 infertility Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
Classifications
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- 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
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
- B29C65/24—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools characterised by the means for heating the tool
- B29C65/30—Electrical means
-
- 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
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/01—General aspects dealing with the joint area or with the area to be joined
- B29C66/05—Particular design of joint configurations
- B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
- B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
- B29C66/112—Single lapped joints
- B29C66/1122—Single lap to lap joints, i.e. overlap joints
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
- B29C66/431—Joining the articles to themselves
- B29C66/4312—Joining the articles to themselves for making flat seams in tubular or hollow articles, e.g. transversal seams
- B29C66/43121—Closing the ends of tubular or hollow single articles, e.g. closing the ends of bags
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/80—General aspects of machine operations or constructions and parts thereof
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/80—General aspects of machine operations or constructions and parts thereof
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/812—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
- B29C66/8122—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/80—General aspects of machine operations or constructions and parts thereof
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/818—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps
- B29C66/8181—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the cooling constructional aspects
- B29C66/81811—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the cooling constructional aspects of the welding jaws
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/80—General aspects of machine operations or constructions and parts thereof
- B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
- B29C66/818—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps
- B29C66/8182—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the thermal insulating constructional aspects
- B29C66/81821—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the thermal insulating constructional aspects of the welding jaws
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
- B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
- B29C66/731—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the intensive physical properties of the material of the parts to be joined
- B29C66/7311—Thermal properties
- B29C66/73113—Thermal conductivity
- B29C66/73114—Thermal conductivity of different thermal conductivity, i.e. the thermal conductivity of one of the parts to be joined being different from the thermal conductivity of the other part
-
- 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
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
- B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
- B29C66/735—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the extensive physical properties of the parts to be joined
- B29C66/7352—Thickness, e.g. very thin
- B29C66/73521—Thickness, e.g. very thin of different thickness, i.e. the thickness of one of the parts to be joined being different from the thickness of the other part
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Description
Die Erfindung bezieht sich auf eine Vorrichtung zum Schweißen von Kunststoff, mit einem Werkzeug zur Anlage an den Kunststoff, wobei das Werkzeug einen streifenförmigen aufheizbaren Bereich aufweist, dessen Verlauf einer anzubringenden Schweißnaht entspricht, und wobei das Werkzeug in dem streifenförmigen Bereich eine reduzierte Wandstärke von dem Kunststoff weg aufweist.The invention relates to a device for welding plastic, with a tool for contact with the plastic, wherein the tool has a strip-shaped heatable region, the course of which corresponds to a weld seam to be applied, and where the tool has a reduced wall thickness away from the plastic in the strip-shaped region.
Vorrichtungen zum Schweißen von Kunststoff der eingangs beschriebenen Art werden insbesondere zum miteinander Verschweißen von zwei Kunststoffolien verwendet, um Kunststoffbeutel zu verschließen oder Kunststoffbeutel insgesamt herzustellen. Besondere Anforderungen werden dabei an die Vorrichtung durch variable Schweißnahtgeometrien, eine möglichst hohe Schweißgeschwindigkeit, unterschiedliche Kunststoffe mit unterschiedlichen Materialeigenschaften, wie Wärmeleitfähigkeit und Erweichungstemperatur, und unterschiedliche Materialstärken gestellt.Devices for welding plastic of the type described above are used in particular for welding two plastic films together in order to seal plastic bags or to produce plastic bags as a whole. Special requirements are placed on the device by variable weld seam geometries, the highest possible welding speed, different plastics with different material properties, such as thermal conductivity and softening temperature, and different material thicknesses.
Telefon 05 51 /710 68-69
Telefax 05 51/7 51 75Telephone 05 51 /710 68-69
Fax 05 51/7 51 75
Postbank Hannover BLZ 250 100 30 Kto. 249219-302Postbank Hannover BLZ 250 100 30 Account 249219-302
Deutsche Bank AG Göttingen
BLZ 260 700 72
Kto. 035 090 000Deutsche Bank AG Göttingen
Bank code 260 700 72
Account 035 090 000
Commerzbank Göttingen BLZ 260 400 30
Kto. 644 700 700Commerzbank Göttingen Bank code 260 400 30
Account 644 700 700
Darüber hinaus gehende Anforderungen werden an eine Vorrichtung der eingangs beschriebenen Art bei ihrer Anwendung im Bereich der Medizintechnik gestellt. Hier muß ein Sterilisieren der mit dem Produkt bei dessen Herstellung in Berührung kommenden Werkzeuge möglich sein.Additional requirements are placed on a device of the type described above when used in the field of medical technology. Here, it must be possible to sterilize the tools that come into contact with the product during its manufacture.
Eine bekannte Vorrichtung zum Schweißen von Kunststoff der eingangs beschriebenen Art weist auf der Rückseite des streifenförmigen Bereichs eine Zufuhr für Heißdampf auf, um den streifenförmigen Bereich mit Heißdampf von seiner Rückseite her aufzuheizen. Beim Aufheizen des streifenförmigen Bereichs mit Heißdampf ist es aber nicht möglich, die Erwärmung tatsächlich auf den streifenförmigen Bereich zu beschränken. So müssen die angrenzenden Teile des Werkzeugs in aufwendiger Weise abgekühlt werden. Insgesamt ist der technische Aufwand für die bekannte Vorrichtung daher groß und der Energieaufwand bei der Verwendung der Vorrichtung ist im Vergleich zu der für das eigentliche Verschweißen benötigten Energie beträchtlich.A known device for welding plastic of the type described above has a supply for hot steam on the back of the strip-shaped area in order to heat the strip-shaped area with hot steam from its back. When heating the strip-shaped area with hot steam, however, it is not possible to actually limit the heating to the strip-shaped area. The adjacent parts of the tool must therefore be cooled in a complex manner. Overall, the technical effort for the known device is therefore great and the energy expenditure when using the device is considerable compared to the energy required for the actual welding.
Eine weitere bekannte Vorrichtung zum Schweißen von Kunststoff verwendet Laserstrahlung zum Erwärmen des Kunststoffs. Hier besteht die Schwierigkeit darin, eine ausreichende Absorption der Laserstrahlen durch den Kunststoff bei gleichzeitig ausreichender Transmission der Laserstrahlen bis in den Kunststoff hinein zu realisieren.Another known device for welding plastic uses laser radiation to heat the plastic. The difficulty here is to achieve sufficient absorption of the laser beams by the plastic while at the same time ensuring sufficient transmission of the laser beams into the plastic.
Der Erfindung liegt die Aufgabe zugrunde, eine Vorrichtung zum Schweißen von Kunststoff der eingangs beschriebenen Art aufzuzeigen, bei der die eingesetzte Energie mit hohem Wirkungsgrad zum Erwärmen des Kunststoffs genutzt wird und die einen einfachen Aufbau aufweist.The invention is based on the object of demonstrating a device for welding plastic of the type described at the outset, in which the energy used is used with high efficiency to heat the plastic and which has a simple structure.
Erfindungsgemäß wird diese Aufgabe bei einer Vorrichtung zum Schweißen von Kunststoff der eingangs beschriebenen Art dadurch gelöst, daß der streifenförmige Bereich Teil mindestens einer guer zu seiner Haupterstreckungsrichtung verlaufenden Wechselstromschleife ist, die über einen Transformator induktiv mitAccording to the invention, this object is achieved in a device for welding plastic of the type described above in that the strip-shaped area is part of at least one alternating current loop running transversely to its main direction of extension, which is inductively connected to
einem Hochfrequenzgenerator verbunden ist. Der über den Transformator mit dem Hochfrequenzgenerator in der Wechselstromschleife induzierte Wechselstrom zeichnet sich neben seiner hohen Frequenz vorzugsweise durch einen großen Strom bei geringer Spannung aus. Bei diesen Randbedingungen tritt der sogenannte Skin-Effekt auf. Das heißt, die Stromleitung beschränkt sich auf die Oberfläche der Leiter der Wechselstromschleife. Unter Ausnutzung des Skin-Effekts ist es möglich, den Widerstand des streifenförmigen Bereichs in die Größenordnung des Gesamtwiderstands der anderen Bestandteile der Wechselstromschleife zu bringen. Entsprechend kann die elektrische Energie, die in der Wechselstromschleife in Wärme umgewandelt wird etwa zur Hälfte zum Aufheizen des streifenförmigen Bereichs genutzt werden, was einen sehr guten Wirkungsgrad bei der Erwärmung des Kunststoffs mit der neuen Vorrichtung impliziert.a high-frequency generator. The alternating current induced in the alternating current loop via the transformer with the high-frequency generator is characterized not only by its high frequency but also by a high current at low voltage. Under these boundary conditions, the so-called skin effect occurs. This means that the current conduction is limited to the surface of the conductors of the alternating current loop. By exploiting the skin effect, it is possible to bring the resistance of the strip-shaped area into the order of the total resistance of the other components of the alternating current loop. Accordingly, about half of the electrical energy that is converted into heat in the alternating current loop can be used to heat the strip-shaped area, which implies a very good efficiency when heating the plastic with the new device.
Die direkte Erwärmung eines Werkzeugs zum Schweißen von Kunststoff durch elektrischen Strom ist an sich von sogenannten Schweißdrähten bekannt, mit denen beispielsweise im Haushaltsbereich Gefrierbeutel verschlossen werden können. Diese Schweißdrähte sind aber, insbesondere im Bereich der Medizintechnik, für industrielle Anwendungen ungeeignet. Im übrigen macht die neue Vorrichtung nicht nur von der elektrischen Beheizung des streifenförmigen Bereichs als solches Gebrauch, sondern sie nutzt zudem in geschickter Weise den Skin-Effekt aus, wobei der Strom in der Wechselstromschleife quer zur Haupterstreckungsrichtung des streifenförmigen Bereichs fließt.The direct heating of a tool for welding plastic using electric current is known from so-called welding wires, which can be used, for example, in the household sector to seal freezer bags. However, these welding wires are unsuitable for industrial applications, especially in the field of medical technology. Furthermore, the new device not only makes use of the electrical heating of the strip-shaped area as such, but also cleverly exploits the skin effect, where the current in the alternating current loop flows transversely to the main direction of extension of the strip-shaped area.
Der Hochfrequenzgenerator kann bei der neuen Vorrichtung einen Wechselstrom mit einer Frequenz von 1 kHz bis 500 kHz erzeugen. Bevorzugt ist der Frequenzbereich von 10 kHz bis 200 kHz.The high-frequency generator in the new device can generate an alternating current with a frequency of 1 kHz to 500 kHz. The frequency range from 10 kHz to 200 kHz is preferred.
Insbesondere bei einer längeren Schweißnaht kann die neue Vorrichtung mehrere Wechselstromschleifen aufweisen, die längs der Schweißnaht angeordnet sind.Particularly in the case of a longer weld seam, the new device can have several alternating current loops arranged along the weld seam.
Diese Wechselstroraschleifen können induktiv mit demselben Hochfrequenzgenerator verbunden sein, so daß auch bei kompliziertem Verlauf der Schweißnaht ein einfacher Aufbau der neuen Vorrichtung gegeben ist.These alternating current loops can be inductively connected to the same high-frequency generator, so that even with a complicated weld seam, the new device can be constructed simply.
Das Werkzeug mit dem streifenförmigen Bereich kann bei der neuen Vorrichtung beispielsweise aus Edelstahl oder aus Invar ausgebildet sein, um den hohen Sterilitätsanforderungen im Bereich der Medizintechnik genüge zu tun. Aus Edelstahl bzw. Invar können glatte, geschlossene und korrosionsfeste Oberflächen ausgebildet werden.The tool with the strip-shaped area in the new device can be made of stainless steel or Invar, for example, in order to meet the high sterility requirements in the field of medical technology. Smooth, closed and corrosion-resistant surfaces can be made of stainless steel or Invar.
In dem streifenförmigen Bereich kann das Werkzeug eine Wandstärke von dem Kunststoff weg von 0,1 bis 0,5 mm aufweisen. Bei dieser geringen Wandstärke hindert selbst die Wärmekapazität des gesamten streifenförmigen Bereichs nicht sein rasches Aufheizen durch den Wechselstrom in der Wechselstromschleife.In the strip-shaped area, the tool can have a wall thickness of 0.1 to 0.5 mm away from the plastic. With this small wall thickness, even the heat capacity of the entire strip-shaped area does not prevent it from heating up quickly by the alternating current in the alternating current loop.
Die Breite des streifenförmigen Bereichs ist an die Geometrie der gewünschten Schweißnaht anzupassen. Sie beträgt typischerweise zwischen 2 und 5 mm.The width of the strip-shaped area must be adapted to the geometry of the desired weld seam. It is typically between 2 and 5 mm.
Um den elektrischen Wechselstromwiderstand der Wechselstromschleife zwar in dem streifenförmigen Bereich hoch zu halten, aber um ansonsten nur geringe elektrische Wechselstromwiderstände in der Wechselstromschleife aufzubauen, ist das Werkzeug in der Wechselstromschleife vorzugsweise über goldbeschichtete Grenzflächen beiderseitig mit jeweils einem Kupferblock kontaktiert. Der Kupferblock kann seinerseits mit den Enden von mehreren offenen sekundären Teilwicklungen eines Transformators kontaktiert sein.In order to keep the electrical alternating current resistance of the alternating current loop high in the strip-shaped area, but to otherwise only build up low electrical alternating current resistances in the alternating current loop, the tool in the alternating current loop is preferably contacted with a copper block on both sides via gold-coated interfaces. The copper block can in turn be contacted with the ends of several open secondary partial windings of a transformer.
Diese sekundären Teilwicklungen des Transformators bestehen vorzugsweise aus mehreren parallelen und gegeneinander isoliert Kupferlitzen, um die widerstandserhöhenden Auswirkungen des Skin-Effekts auf die sekundären Teilwicklungen in der Wechselstromschleife möglichst gering zu halten. Die Aufteilung derThese secondary windings of the transformer preferably consist of several parallel and mutually insulated copper strands in order to keep the resistance-increasing effects of the skin effect on the secondary windings in the AC loop as low as possible. The distribution of the
Wicklung auf einzelne parallele und gegeneinander isolierte Kupferlitzen kann auch auf der Seite der Primärwicklung erfolgen.Winding on individual parallel and mutually insulated copper strands can also be done on the primary winding side.
Die Primärwicklung ist vorzugsweise mit den sekundären Teilwicklungen des Transformators ineinander gewickelt, um das magnetische Wechselfeld des Transformators möglichst effektiv auszunutzen.The primary winding is preferably wound together with the secondary windings of the transformer in order to use the alternating magnetic field of the transformer as effectively as possible.
In dem Werkzeug können parallel zu dem streifenförmigen Bereich verlaufende Kanäle für ein Kühlmedium vorgesehen sein. Diese Kanäle können zum einen zum Abkühlen des streifenförmigen Bereichs nach dem Anbringen der Schweißnaht und damit zum wieder Erstarren des Kunststoffs verwendet werden. Zum anderen dienen sie dazu, die von dem streifenförmigen Bereich in das restliche Werkzeug abfließende Wärme abzuführen.Channels for a cooling medium can be provided in the tool, running parallel to the strip-shaped area. These channels can be used to cool the strip-shaped area after the weld seam has been made and thus to solidify the plastic again. They also serve to dissipate the heat flowing from the strip-shaped area into the rest of the tool.
Die Erfindung wird im folgenden anhand von Ausführungsbeispielen näher erläutert und beschrieben. Es zeigt:The invention is explained and described in more detail below using exemplary embodiments. It shows:
Figur 1 eine perspektivische Darstellung einer schematisierten Ausführungsform der neuen Vorrichtung,Figure 1 is a perspective view of a schematic embodiment of the new device,
Figur 2 ein Detail der Vorrichtung gemäß Figur 1 undFigure 2 shows a detail of the device according to Figure 1 and
Figur 3 ein Ersatzschaltbild für eine Fortentwicklung der Vorrichtung gemäß Figur 1.Figure 3 is an equivalent circuit diagram for a further development of the device according to Figure 1.
Die in Figur 1 dargestellte Vorrichtung dient zum Verschweißen von zwei Kunststoffolien 8 im Bereich einer schraffiert zwischen den beiden Kunststoffolien 8 angedeuteten Schweißnaht 18. Die beiden Kunststoffolien 8 befinden sich beim Anbringen der Schweißnaht 18 zwischen einem Werkzeug 1 und einer Gegenplatte 9. Das Werkzeug 1 ist aus Edelstahl oder Invar ausgebildet. Das Werkzeug 1 weist oberhalb der Schweißnaht 18 einen streifenförmigen Bereich 2 auf, in dem die Wandstärke 16, 17 des Werkzeugs 1 von den Kunststoffolien 8 weg reduziert ist. Das heißt,The device shown in Figure 1 is used to weld two plastic films 8 in the area of a weld seam 18 indicated by hatching between the two plastic films 8. When the weld seam 18 is applied, the two plastic films 8 are located between a tool 1 and a counter plate 9. The tool 1 is made of stainless steel or Invar. The tool 1 has a strip-shaped area 2 above the weld seam 18 in which the wall thickness 16, 17 of the tool 1 is reduced away from the plastic films 8. This means that
die Wandstärke 17 im Bereich des streifenförmigen Bereichs ist kleiner als die Wandstärke 16 außerhalb des streifenförmigen Bereichs. Quer zu dem streifenförmigen Bereich 2 ist eine Wechselstromschleife 1,3,5 ausgebildet. Von dem Werkzeug 1 verläuft die Wechselstromschleife 1,3,5 über eine vergoldete Grenzfläche 14 und einen Kupferblock 3 zu mehreren sekundären Teilwicklungen 5 eines Transformators 5,6,11 und von den anderen Enden der sekundären Teilwicklungen 5 wieder zu einem zweiten Kupferblock 3 und über eine vergoldete Grenzfläche 14 zurück zu dem Werkzeug 1. Die vergoldeten Grenzflächen 14 sind zur Reduzierung des Wechselstromwiderstands in der Wechselstromschleife 1,3,5 an den Grenzflächen zwischen den Kupferblöcken 3 und dem Werkzeug 1 vorgesehen. Maximal ist der Wechselstromwiderstand der Wechselstromschleife 1,3,5 in dem streifenförmigen Bereich 2. Hier ist nicht nur der Materialquerschnitt quer zu der Stromflußrichtung am geringsten, hier machen sich auch die Auswirkungen des sogenannten Skin-Effekts in der Wechselstromschleife 1, 3, 5 am stärksten bemerkbar. Der Skin-Effekt tritt auf, weil über den Transformator 5,6,11 eine hochfrequente Wechselspannung mit großem Strom in der Wechselstromschleife 1,3,5 induziert wird. Auf der Primärseite des Transformators 5,6,11 ist ein Hochfrequenzgenerator 12 über Zuleitungen 13 an die Primärwicklung 6 angeschlossen.the wall thickness 17 in the area of the strip-shaped area is smaller than the wall thickness 16 outside the strip-shaped area. An alternating current loop 1,3,5 is formed transversely to the strip-shaped area 2. From the tool 1, the alternating current loop 1,3,5 runs over a gold-plated interface 14 and a copper block 3 to several secondary partial windings 5 of a transformer 5,6,11 and from the other ends of the secondary partial windings 5 again to a second copper block 3 and over a gold-plated interface 14 back to the tool 1. The gold-plated interfaces 14 are provided to reduce the alternating current resistance in the alternating current loop 1,3,5 at the interfaces between the copper blocks 3 and the tool 1. The alternating current resistance of the alternating current loop 1,3,5 is at its maximum in the strip-shaped area 2. Here, not only is the material cross-section transverse to the direction of current flow the smallest, but the effects of the so-called skin effect in the alternating current loop 1, 3, 5 are also most noticeable here. The skin effect occurs because a high-frequency alternating voltage with a large current is induced in the alternating current loop 1,3,5 via the transformer 5,6,11. On the primary side of the transformer 5,6,11, a high-frequency generator 12 is connected to the primary winding 6 via supply lines 13.
Figur 2 skizziert, daß die Primärwicklung 6 und die sekundären Teilwicklungen 5 des Transformators 5,6,11 ineinander auf den Transformatorkern 11 gewickelt sind. Hierdurch wird die Ausnutzung des magnetischen Wechselfelds, welches von der Primärwicklung hervorgerufen wird, verbessert.Figure 2 shows that the primary winding 6 and the secondary partial windings 5 of the transformer 5,6,11 are wound into one another on the transformer core 11. This improves the utilization of the alternating magnetic field generated by the primary winding.
Die Wandstärke 17 des Werkzeugs 1 in dem streifenförmigen Bereich 2 beträgt 0,3 mm, die Breite 19 des streifenförmigen Bereichs 3 mm. Die Tiefe 4 der Kupferblöcke 3 und damit der Wechselstromschleife 1,3,5 kann je nach Anforderungen an die Schweißnaht 18 3 bis 200 ram betragen. Hier sind es 10 mm. Durch den Skin-Effekt dringt der Wechselstrom in der Wechselstromschleife 1,3,5 in dem streifenförmigen Bereich bei einerThe wall thickness 17 of the tool 1 in the strip-shaped area 2 is 0.3 mm, the width 19 of the strip-shaped area is 3 mm. The depth 4 of the copper blocks 3 and thus of the alternating current loop 1,3,5 can be 3 to 200 ram depending on the requirements of the weld seam 18. Here it is 10 mm. Due to the skin effect, the alternating current in the alternating current loop 1,3,5 penetrates into the strip-shaped area at a
Frequenz von 100 kHz nur etwa 0,05 mm in das Material des Werkzeugs 1 ein. Hierdurch wird ein hoher effektiver Widerstand des streifenförmigen Bereichs 2 erreicht, der etwa genauso groß ist, wie der elektrische Wechselstromwiderstand der anderen Bestandteile der Wechselstromschleife 1,3,5. Damit ist ein rasches Aufheizen der Kunststoffolien 8 im Bereich der Schweißnaht möglich. Die Gegenplatte 9 ist zur thermischen Isolierung der Schweißnaht 18 aus einem Isolationsmaterial, d. h. hier aus Silikon, ausgebildet. Zum Abkühlen des streifenförmigen Bereichs 2 und damit der Schweißnaht 18 nach dem Schweißen und zum Abführen der aus dem streifenförmigen Bereich 2 seitlich in die anderen Teile des Werkzeugs 1 abgeführten Wärmeenergie sind in dem Werkzeug 1 Kanäle 7 für ein hier nicht dargestelltes Kühlmedium vorgesehen.Frequency of 100 kHz only penetrates about 0.05 mm into the material of the tool 1. This achieves a high effective resistance of the strip-shaped area 2, which is about as high as the electrical alternating current resistance of the other components of the alternating current loop 1, 3, 5. This enables the plastic films 8 in the area of the weld seam to heat up quickly. The counter plate 9 is made of an insulating material, i.e. here silicone, for thermal insulation of the weld seam 18. To cool the strip-shaped area 2 and thus the weld seam 18 after welding and to dissipate the heat energy dissipated laterally from the strip-shaped area 2 into the other parts of the tool 1, channels 7 for a cooling medium (not shown here) are provided in the tool 1.
Figur 3 zeigt eine Weiterentwicklung der Vorrichtung gemäß Figur 1. Hier ist ein einziger Hochfrequenzgenerator 12 zur induktiven Kopplung mit verschiedenen Wechselstromschleifen vorgesehen, die jeweils durch eine sekundäre Teilwicklung und Ersatzschaltbilder 10 bestehend aus Widerständen 15 angedeutet sind. Die einzelnen Wechselstromschleifen sind bei der konkreten Ausführungsform der Vorrichtung hintereinander entlang der gewünschten Schweißnaht 18 anzuordnen.Figure 3 shows a further development of the device according to Figure 1. Here, a single high-frequency generator 12 is provided for inductive coupling with various alternating current loops, each of which is indicated by a secondary partial winding and equivalent circuit diagrams 10 consisting of resistors 15. In the specific embodiment of the device, the individual alternating current loops are to be arranged one behind the other along the desired weld seam 18.
BEZUGSZEICH E NLIST E REFERENCE NUMBERS LIST
Claims (12)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE29709456U DE29709456U1 (en) | 1997-05-30 | 1997-05-30 | Device for welding plastic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE29709456U DE29709456U1 (en) | 1997-05-30 | 1997-05-30 | Device for welding plastic |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE29709456U1 true DE29709456U1 (en) | 1998-10-01 |
Family
ID=8040954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DE29709456U Expired - Lifetime DE29709456U1 (en) | 1997-05-30 | 1997-05-30 | Device for welding plastic |
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| Country | Link |
|---|---|
| DE (1) | DE29709456U1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371157C (en) * | 2004-02-05 | 2008-02-27 | 凌正然 | Workbench of high-frequency welding machine and heat sealing shaping assembly of high-frequency electrode plate |
| FR3141635A1 (en) * | 2022-11-03 | 2024-05-10 | Gys | Device and method for fixing two plastic parts by welding |
-
1997
- 1997-05-30 DE DE29709456U patent/DE29709456U1/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371157C (en) * | 2004-02-05 | 2008-02-27 | 凌正然 | Workbench of high-frequency welding machine and heat sealing shaping assembly of high-frequency electrode plate |
| FR3141635A1 (en) * | 2022-11-03 | 2024-05-10 | Gys | Device and method for fixing two plastic parts by welding |
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