The present invention relates to a method for changing material in an extrusion device comprising at least two supply devices for supplying feedstock for an extruder, comprising the following steps: identifying a change request for changing the material in the extrusion device, preparing the supply devices for changing the material, separating at least two supply devices from the feed of feedstock to the extruder, discharging feedstock from the separated supply devices, filling subsequent material into the empty supply devices.

An apparatus for starting an extrusion process, including at least a drawing device having a main frame, a platform arranged on the main frame, a cable winch arranged on the platform and having a drum, and a wire cable that can be wound up on the drum of the cable winch and pulls an extruded plastics pipe in an extrusion line by way of deflection rolls until the pipe is taken over by a take-off device, wherein the platform is movable transversely to an extrusion direction.

Provided is a blow-molding method capable of suppressing generation of blister-like bubbles and producing a high quality hollow molded article when forming a thick hollow molded article by blow-molding. A blow-molding method includes setting a die-slit interval in a die head according to a target wall thickness of a hollow molded article to be molded, extruding a molten resin in an accumulator into a cylindrical shape from the die slit to form a parison, and molding the parison in a mold. The die-slit interval is made smaller than a value set according to the target wall thickness at start of extrusion, and then is increased to match the value set according to the target wall thickness. The value set according to the target wall thickness is preferably corrected considering wall thickness reduction due to drawdown. The wall thickness of the hollow molded article is preferably 3.5 mm or more.

The invention relates to a process for the production of articles, exemplarily a plastic article, by means of an extruder (1) to which a first plastic composition of a first main component and at least one associated minor component is supplied from a first group of dosing stations (21, 24). According to the invention, during the production time of a first production order there is prepared a second group of dosing stations (31, 33) at the extruder for a second production order for which a second plastic composition of a second main component and at least one associated minor component that is different from the first plastic composition has to be supplied to the extruder. After completion of the first production order it is reset to the second production order by terminating the supply of the first plastic composition by closing a first shut-off device (8) and starting the supply of the second plastic composition by opening a second shut-off device (8′).

A method for using the quantity of heat output from an extrudate during a cooling operation in an extrusion process, wherein a fluid, in particular air, is guided along the extrudate and/or through the die counter to an extrusion direction, at least some of the heat from the extrudate and/or the die is transmitted to the fluid, the heated fluid is supplied from a first sub region of a process chain, comprising at least one die, a calibrating and cooling device and a take-off apparatus, via a connecting region, preferably consisting of at least one connecting pipe, to a second sub region of the process chain, comprising at least one suction apparatus. In the connecting region, an extraneous fluid can be added to the heated fluid in order to reduce the actual temperature of the heated fluid at least below a predetermined maximum value before said fluid is supplied to the second sub region of the process chain.

The present invention relates to a method for changing material in an extrusion device comprising at least two supply devices for supplying feedstock for an extruder, comprising the following steps: identifying a change request for changing the material in the extrusion device, preparing the supply devices for changing the material, separating at least two supply devices from the feed of feedstock to the extruder, discharging feedstock from the separated supply devices, filling subsequent material into the empty supply devices.

The invention relates to a process for the production of articles, exemplarily a plastic article, by means of an extruder (1) to which a first plastic composition of a first main component and at least one associated minor component is supplied from a first group of dosing stations (21, 24). According to the invention, during the production time of a first production order there is prepared a second group of dosing stations (31, 33) at the extruder for a second production order for which a second plastic composition of a second main component and at least one associated minor component that is different from the first plastic composition has to be supplied to the extruder. After completion of the first production order it is reset to the second production order by terminating the supply of the first plastic composition by closing a first shut-off device (8) and starting the supply of the second plastic composition by opening a second shut-off device (8′).

An apparatus for starting an extrusion process, including at least a drawing device having a main frame, a platform arranged on the main frame, a cable winch arranged on the platform and having a drum, and a wire cable that can be wound up on the drum of the cable winch and pulls an extruded plastics pipe in an extrusion line by way of deflection rolls until the pipe is taken over by a take-off device, wherein the platform is movable transversely to an extrusion direction.

The present invention relates to a method for the step-by-step guidance of a machine operator of an extrusion device for a film machine when changing from an application formula to a subsequent formula, comprising the following steps: identifying a formula change request, displaying the formula change request for the machine operator, displaying at least one concluding step to be performed for the application formula, identifying a confirmation of the machine operator for the at least one concluding step, displaying at least one preparatory step to be performed for the subsequent formula, identifying a confirmation of the machine operator for the at least one preparatory step, and concluding the change from the application formula to the subsequent formula.

An extrusion device that produces plastic film includes at least two feed units that feed feedstock for an extruder, wherein, in each feed unit an automatic cleaning device is arranged for a removal of feedstock from the feed unit when changing material in the extrusion device.