Abstract:
A method of making a coil of a plastic foil forms a flat web by extrusion through a wide slit nozzle or by film blowing and determines the thickness-error profile of the foil wound on a coil. Based upon monitoring the contour of the coil the inverse thickness-error profile is produced by control of the die gap and wound on the coil so that the coil is built-up alternatingly with the original thickness-error profile and the inverse thickness-error profile until completion of winding so that it has a sufficiently cylindrical coil contour.
Abstract:
The apparatus for making a plastic foil by blowing into an extruded thermoplastic tube comprises a rotating extruder head with at least one circular outlet gap for the plastic tube, an air blowing device and a cooling device including two circular cooling air outlets surrounding the circular outlet gap of the extruder head. Cooling air duct structures are connected to a common cooling air blower. A cooling air distributor unit has a cooling air feed device for each cooling air outlet. The cooling air feed devices are aerodynamically independent of each other. The aerodynamically independent cooling air feed devices are connected to a common cooling air duct structure. Each cooling air feed device has an air flow control device.
Abstract:
A method of producing a thermoplastic foil with reduced thickness tolerances in which close to the head the temperatures of the mass flow emerging from the heat at various regions corresponding to tempering sectors are detected, the temperature measurements are averaged and the averages are used to form a set point value with which the individual averages are compared and the comparison used to generate a correction signal which is applied to the temperature controller of the respective sector.
Abstract:
Platelike webs of thermoplastic material are produced by extruding a strip of the thermoplastic material and passing it through a roll unit having a pair of intake rolls upstream of which a bank of the material is formed. The delivery speed is controlled in response to the bearing pressure of the intake rolls.
Abstract:
The apparatus for winding a foil sheet, especially a plastic foil sheet, on a roll core is used in a step in the winding of a foil sheet into a foil sheet roll with a foil sheet winding machine. The apparatus comprises a contacting roll, a roll core receptacle and a cross cutter. A roll core put in the roll core receptacle is placed on the contacting roll and is drivable by it with the intervening foil sheet running to the downstream foil sheet roll. The foil sheet is cuttable with the help of the cross cutter between the roll core and the downstream foil sheet roll. Further the leading end piece of the next following foil sheet formed by cutting is receivable by the roll core. Above the roll core received in the roll core receptacle a foil sheet press device is mounted which is placeable on the roll core by a pivot motion and has a press element travelling with it during pivoting. The press element, advantageously a press belt, embraces the roll core on the side of the roll core facing away from contacting roll and forms an engaging wedge space with the roll core. An air blower tube is located between the engaging wedge space and the cross cutter under the next uncut foil sheet. The blower air streams from this blower tube are directed in the engaging wedge space and/or substantially parallel to the engaging direction of the engaging wedge space to assist in engaging the next following foil sheet on the roll core.
Abstract:
A method for continuously producing flat cables with electric conductors embedded in an isolating material which are arranged at a certain distance from each other, parallel to each other. According to this invention, the band shaped conductors are guided separately in a plane forming two sides of a surface. The surface sides have insulating layers based on thermoplastic synthetic materials. According to this invention, at least one of the insulating layers which covers the surface sides is produced by extrusion coating of a thermoplastic melt.
Abstract:
The apparatus for extrusion of a thermoplastic material comprises an extruder with an extruder screw and an extruder housing with a feed opening, a feed device, a drive with a variable speed motor and a regulating device cascade for the mass temperature. The regulating device cascade has a plurality of tempering zones, at least one mass temperature detector and at least one tempering device. One tempering zone connected directly to the feed opening is part of the regulating device cascade and the temperature in the one tempering zone is corrected by a set value during a mass temperature variation. To provide a temperature regulation range which does not experience disturbing decreases, the tempering zone at the feed opening has only a cooling device and has a grooved sleeve. The feed device is a gravity feed device and belongs to an additional regulating loop which controls the rotational speed of a variable speed motor. When an excessive value of the mass temperature and throughput occurs, the regulating loop to which the gravity feed device belongs causes the drive speed of the variable speed motor to be reduced; an insufficient value gives rise to an increased motor speed. The regulating device cascade and the additional regulating loop are connected by a logic unit, advantageously a computer, which compensates for variations.
Abstract:
The weight components along a pair of support arms for a coil of a foil web provide inputs to a controller whose other input is from an angle detector measuring the inclination of said arms so that the controller can operate a control member such as a fluid cylinder to maintain a constant contact pressure between the coil and a contact drum applying the web to the coil.
Abstract:
A foil-blowing apparatus has at least one deformable lip defining the annular orifice from which the thermoplastic tube which is blown to form the coil is extruded. The lip can be provided with an array of effectors which, in response to a thickness-profile measuring unit, can radially deform the lip to correct thickness errors. The lip can be under prestress and the radial deformation is effected by measuring the thickness and superimposing a radial force on the prestress.
Abstract:
An apparatus for blow extruding a synthetic-resin tube has a nozzle having an annular mouth generally centered on a longitudinal axis for longitudinally outwardly extruding a tubular synthetic-resin strand, an inner stabilizing tube extending longitudinally outward from the nozzle within the mouth thereof and having an outer end spaced a predetermined longitudinal distance from the mouth, and an outer stabilizing tube surrounding the inner tube and defining a longitudinal passage therewith, extending longitudinally outward from the nozzle within the mouth thereof, and having an outer end lying between the outer end of the inner tube and the mouth. The passage opens outward between the outer ends. Cool air is fed to the passage at the mouth and to a space defined between the strand where it emerges from the mouth and the outer tube for flow of this cooling air longitudinally outward between the strand and the outer tube and from the outer end of the outer tube. Thus the strand is expanded transversely generally at the outer ends of the tubes. The cooling air is withdrawn from within the strand by drawing this cooling air into the outer end of the inner tube and longitudinally backward through the inner tube.