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
  • 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
  • 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
  • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
  • B29C65/1403—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the type of electromagnetic or particle radiation
  • B29C65/1412—Infrared [IR] radiation
• • 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
  • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
  • B29C65/1429—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface
  • B29C65/1435—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. transmission welding
• • 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
  • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
  • B29C65/1429—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface
  • B29C65/1445—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface heating both sides of the joint
• • 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
  • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
  • B29C65/1429—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface
  • B29C65/1464—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface making use of several radiators
  • B29C65/1467—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface making use of several radiators at the same time, i.e. simultaneous welding
• • 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
  • B29C66/70—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
  • B29C66/739—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 material of the parts to be joined being a thermoplastic or a thermoset
  • B29C66/7392—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 material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
  • B29C66/73921—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 material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
• • 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
  • 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
  • B29C2035/0822—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 IR radiation
• • 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
  • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
  • B29C66/832—Reciprocating joining or pressing tools

Definitions

• This invention relates to joining of plastic.
• One of the more preferred methods is to use a welding technique where the faces of the respective plastics are raised to a temperature of above a melt temperature of the plastic and then the plastics are pushed together under substantive pressure.
• thermoplastics materials are compatible materials for effecting such a heated weld join.
• a further method of joining sheet plastics is a hot stamp die.
• the object of this invention is, therefore, to propose means and a method of effecting a joining of plastics of the type discussed which will avoid substantially the problems as discussed.
• thermoplastics material by directing a radiant heating through reflector means such that radiation emanating from such a radiant heater is directed substantially perpendicularly to the plastics surface and effecting such heating with such an intensity of radiation that will quickly raise the temperature of the plastics being subjected to the radiation to a temperature of above the melt point of the plastics.
• the heating is maintained in an aligned orientation longitudinally with respect to a direction of travel of the tape so that a portion of the tape to be heated will be maintained substantially beneath the radiant heater throughout the length of the heating means.
• such plastics materials as are being drawn past such heating means are held so that the parts adjacent the heated portion are retained in constant alignment and are kept in such constant alignment subsequent to such heating effect so that where there are two or more thicknesses of plastics material, these will be held together and to an extent that they will join by being sufficiently heated.
• the sheets of plastics material are held in adjoining relationship face upon face and there are radiant heaters with an outlet slot aligned along both an upper side and a lower side of such passing two sheets or more of such plastics material.
• Each of the radiant heaters is arranged so that by reflection or otherwise they provide a high intensity of radiant heat which also because of the reflection is substantively aligned to be directed only along and through a narrow gap.
• the shape of reflector can thereby including a plurality of reflective faces each of which reflect the radiant output of a strip heater such that the radiation is substantially directed further away from the direction of the strip heater and such that an outlet from a body housing such heater has a gap aligned in the elongate direction of the strip heater but such that a high proportion of the out part of the strip heater is thus directed to issue from the strip in a direction which is substantively away from the strip heater source.
• Such an output gap can be located in very close vicinity to the plastics material to be welded and in the case where the plastics material is a sheet passing along the direction which is parallel to the strip source then this can be held within a millimetre or so away from the plastics outer surface.
• plastics materials can be heated throughout their thickness very quickly to a temperature above melt temperature, that this temperature appears to be reached throughout the thickness of the plastics material only where substantially aligned with the output from the focused radiant heater source and that where two plastics sheets are adjoining there is a resulting intermix which is effective to cause a very strong and effective heat weld.
• the sheets pass beneath upper and lower focused radiant heaters in the manner described and are simply kept, while being heated, in an adjoining surface relationship whereas it is discovered that there is an equivalently narrow band that is melted to melt temperature of the plastics material without substantively losing the integrity of the adjacent plastics parts, that there is uniform melting through mutual thicknesses of the plastics sheets and that subsequent cooling finds the sheets joined by intermoulding of the respective plastics of the sheets providing a substantive bond.
• thermoplastics welding arrangement including a filament source of infrared radiation, a reflector body providing an elongate reflector chamber having a substantially constant cross-sectional shape along the elongate length of the reflector chamber, the shape including a wide chamber part, and a first side extending from a first side of the wide chamber part to a first side defining an outlet gap, and a second side extending from a second side of the wide chamber part to a second side defining the outlet gap, the respective first and second sides converging closer together from the position at the wide chamber part as they progress toward the outlet gap to define thereby a narrow outlet gap, the filament source being located within the wide chamber part and extending substantially the length of the reflector chamber, and means to locate the thermoplastics sheet to be welded together, across a mouth of the outlet gap.
• the wide chamber part includes a part of convex shape positioned opposite the outlet gap.
• the infrared radiation is within a range of medium wave length and, preferably, within the range of 2.2 to 2.8 microns wave length. Further, it would appear that significant advantage is gained by providing that the incident angle 10 of any radiant energy failing on the thermoplastics sheet to be welded would lie within the range of 45 degrees to 90 degrees.
• FIG. 1 is a cross-sectional view through an arrangement organised in accordance with the preferred embodiment and comprising two radiant heaters enclosed within respective reflector arrangements and respectively directing focused radiant heating onto a composite plastics strip,
• FIG. 2 illustrates the manner in which the focused radiant heating intersects and is caught between the respective surfaces of the plastic sheeting
• FIG. 3 is a side elevation of the arrangement as in FIG. 1.
• thermoplastics material specifically polythene and the radiant heating source temperature is chosen so as to effect a substantial penetration into the plastics material and, to this end, source temperature is chosen as between 900-1000 degrees centigrade, the heating element is chosen for this purpose to be an aluminium alloy, and the element is housed within a quartz glass housing 1.
• the source is providing a medium wave length infrared radiant source within the wave length of 2.2 to 2.8 microns.
• the quartz glass 1 is chosen so as to be substantially capable of transmitting without substantial loss infrared transmission in this wave length.
• the reflector bodies each cast from metal and having a gold plated inner reflective chamber 2 includes a rearwardmost convex part 3, two concave parts 4 and 5, defining a wide chamber part and then in stepping fashion, a plurality of convergingly located reflector surfaces 6 provided by a first side extending from a first side of the wide chamber part 2 to an outlet gap 8 each substantially parallel one to the other and each aligned so that they are substantially transverse or perpendicular to the target tape 7 which comprises the polythene thermoplastics material in sheet form held together as three composite layers.
• the shape in cross section is constant along the elongate length of the reflector body.
• the elongated outlet gap 8 through which the concentrated radiant heating is adapted to pass and the gap is positioned and shaped such that only radiation with the relatively perpendicular alignment (approximately 45 degrees to 90 degrees incident angle 10 to the sheet surface) will pass through the gap and be directed at the tape.
• the tape is being caused to constantly move through the radiated area as is shown particularly in FIG. 3, and the length of the radiated area is chosen in respect of the tape speed so as to effect at the end of the passage of the tape a sufficient selected melting such that the respective tapes will have been caused to flow together and weld.
• this essentially means that the radiant energy is being mostly transmitted out from the reflector area.
• the next issue is that the direction of radiant energy is such that it will be predominantly transverse to the sheet of thermoplastics material which is to be subjected to the heating effect.
• the angle of incidence would be substantially within the range of 45 degrees to 90 degrees and would have predominance within the range of 60 degrees to 90 degrees relative to the planar alignment of a target surface.
• a reflector housing which defines a longitudinal space having a longitudinal heating element, a back reflector surface of convex shape extending along the length of the reflector surface, then extending from both sides of the convex shape, parts which are of concave shape then terminating to each of two sides which are then converging to a narrowest outlet gap which is spaced a substantial distance away from the supplying radiant filament.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)

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Publications (1)

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Family Cites Families (9)

• 1988
  • 1988-10-19 WO PCT/AU1988/000410 patent/WO1989003758A1/en not_active Ceased
  • 1988-10-19 EP EP88909270A patent/EP0335951A1/de not_active Withdrawn

Non-Patent Citations (1)

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