Systems and methods are provided for controlling welding. One embodiment is a method for controlling welding. The method includes initiating induction welding by operating an induction coil along a weld interface of a first composite part comprising a matrix of thermoplastic reinforced by fibers, in order to join the first composite part to a second composite part, determining a measured magnetic field strength at a location distinct from the induction coil, and determining a welding temperature at the weld interface of the first composite part based on the measured magnetic field strength.

A method for joining moulded parts by electromagnetic welding. A joining inductor is moved along contact surfaces of the moulded parts, generating an electromagnetic field in an induction-sensitive component of the moulded part(s) to heat a thermally activated coupling means of the moulded part(s) to above a melting temperature of the coupling means. The strength of the electromagnetic field suitable for joining is determined by previously moving a sensing inductor along the contact plane, generating a relatively weak electromagnetic field to slightly heat the thermally activated coupling means to a sensing temperature, measuring the field strength generated by the sensing inductor in the moulded part(s), determining a discrepancy between the measured field strength of the sensing inductor and the field strength suitable for joining, and adjusting the field strength suitable for joining to close the discrepancy. A device for carrying out the method.

The present disclosure is concerned with a method of forming a seal with a polyethylene based film structure. The polyethylene based film structure has at least one layer formed with an oriented polyethylene having a predetermined melting temperature (T.sub.m). A conductive heat sealing device provides heat to form the seal, where a first sealing bar of the conductive heat sealing device operates at a first operating temperature of at least 10 degrees Celsius (° C.) below the T.sub.m of the oriented polyethylene in the polyethylene based film structure and a second sealing bar of the conductive heat sealing device operates at a second operating temperature of at least 15° C. higher than the operating temperature of the first sealing bar. The seal formed with the polyethylene based film structure retains at least 99 percent of its original surface area prior to forming the seal.

A method for joining moulded parts by electromagnetic welding. A joining inductor is moved along contact surfaces of the moulded parts, generating an electromagnetic field in an induction-sensitive component of the moulded part(s) to heat a thermally activated coupling means of the moulded part(s) to above a melting temperature of the coupling means. The strength of the electromagnetic field suitable for joining is determined by previously moving a sensing inductor along the contact plane, generating a relatively weak electromagnetic field to slightly heat the thermally activated coupling means to a sensing temperature, measuring the field strength generated by the sensing inductor in the moulded part(s), determining a discrepancy between the measured field strength of the sensing inductor and the field strength suitable for joining, and adjusting the field strength suitable for joining to close the discrepancy. A device for carrying out the method.

The present invention relates to a method for connecting two joining elements, these elements being connected by means of a thermally activatable adhesive with a flat heating element arranged therein, by suitable heating of the adhesive. The invention also relates to an assembly produced in this way from two joining elements and to an arrangement designed for carrying out a corresponding method.

Systems and methods are provided for controlling welding. One embodiment is a method for controlling welding. The method includes initiating induction welding by operating an induction coil along a weld interface of a first composite part comprising a matrix of thermoplastic reinforced by fibers, in order to join the first composite part to a second composite part, determining a measured magnetic field strength at a location distinct from the induction coil, and determining a welding temperature at the weld interface of the first composite part based on the measured magnetic field strength.

Systems and methods are provided for controlling welding. One embodiment is a method for controlling welding of a composite part. The method includes locating a linear fiber optic sensor along a composite part comprising a matrix of thermoplastic reinforced by fibers, measuring temperatures along the weld line via the linear fiber optic sensor, performing induction welding at the composite part along the weld line, determining a continuum of weld temperatures along the weld line, and controlling the induction welding based on the continuum of weld temperatures.

The embodiment provides a heat-sealing apparatus and a method of accurately controlling heat sealing temperature by measuring the temperature using a heat-sealing apparatus which heat-seals a pair of heat seal materials by nipping them between a pair of heating bodies. The method of heat-sealing includes mounting a cover material on the surface of at least one of the heating bodies to be in contact with the heat seal material, attaching a minute temperature sensor to the surface of the cover material on the side to be in contact with the heat seal material, and controlling temperature of welding face by the temperature detected by the minute temperature sensor, and an apparatus therefor.

A method for determining whether a sealing area (13) of a primary packaging container (1) for an ophthalmic lens is unacceptable for properly sealing a foil to the sealing area (13) comprises the steps of taking an infrared image (7) of the primary packaging container (1); determining in the infrared image (7) a plurality of individual pixels (700-709) which are arranged along an area (73) corresponding to the sealing area (13) of the primary packaging container (1); determining from the infrared image (7) the temperature (T.sub.0, T.sub.1, T.sub.2) of the individual pixels (700-709), and determining that the sealing area (13) is unacceptable in case the following conditions are fulfilled: a) the temperature (T.sub.1) of each individual pixel of a predetermined number of coherently arranged individual pixels (700, 703, 706) is lower than a reference temperature (T.sub.0), and b) the difference between the temperature (T.sub.1) of each individual pixel (700; 703; 706) of the coherently arranged pixels (700, 703, 706) and the reference temperature (T.sub.0) exceeds a predetermined threshold.

A method for improving the heat sealability of a packaging material and a method for manufacturing a heat-sealed container or package are described. The material can be polymer-coated packaging paper or cardboard, or a polymeric packaging film. The material includes a polymer layer that contains polyester, particularly polylactide, the heat sealability of which is improved by ultraviolet radiation. Polylactide is useful as such or when blended, for example, with other biodegradable polyester. The containers and packages thus manufactured include disposable drinking cups and cardboard carton and box packages.