A method for controlling the thickness of a continuous elongated element made of elastomeric material, applied according to coils wound on a forming support, includes: advancing a head end of the continuous elongated element toward the forming support; subjecting, during the advancement, the continuous elongated element to a first stretching with a first stretch coefficient before applying on the forming support; and subjecting, during the advancement, the continuous elongated element to a second stretching with a second stretch coefficient during the application on the forming support. During the first stretching, a span of the continuous elongated element adjacent to the head end is stretched with a supplementary stretch coefficient greater than the first stretch coefficient, in a manner so as to confer, also to the span adjacent to the head end, a stretch and a section similar or substantially equivalent to those of the rest of the continuous elongated element.

A method for reducing gel in a polymer kneaded compound flowing in a polymer flow duct includes flowing a polymer kneaded compound in a polymer flow duct to a gel reduction mechanism including a gel reduction member having one or more through holes defining a squeezing flow path having a flow path cross-sectional area smaller than the polymer flow duct. The squeeze ratio S1/S2 of the squeezing flow path is 25 to 177.8, where S1 is a flow path cross-sectional area of the polymer flow duct and S2 is a sum total of flow path cross-sectional area of the squeezing flow path, to generate an extensional flow in the kneaded compound.

A method for reducing gel in a polymer kneaded compound flowing in a polymer flow duct includes flowing a polymer kneaded compound in a polymer flow duct to a gel reduction mechanism including a gel reduction member having one or more through holes defining a squeezing flow path having a flow path cross-sectional area smaller than the polymer flow duct. The squeeze ratio S1/S2 of the squeezing flow path is 25 to 177.8, where S1 is a flow path cross-sectional area of the polymer flow duct and S2 is a sum total of flow path cross-sectional area of the squeezing flow path, to generate an extensional flow in the kneaded compound.

A method for forming a belt-like rubber sheet S by extruding rubber on a drum outer peripheral surface 3a by an extruder 2 includes: a front end forming step for forming a front end S1 having a wedge-shaped cross section; an intermediate part forming step for forming an intermediate part S2 having a desired thickness; and a rear end forming step for forming a rear end S3 having a wedge-shaped cross section by gradually decreasing an extrusion amount of the rubber to zero from a predetermined extrusion amount in a predetermined time, gradually decreasing the rotational speed of the drum outer peripheral surface 3a to zero from a predetermined rotational speed in the predetermined time, and gradually decreasing a distance from the drum outer peripheral surface 3a to a die 21 to an extrusion end distance from a predetermined distance in the predetermined time.

In an extrusion molding apparatus according to an embodiment, a control unit configured to perform feedback control for a rotation speed of a pump so as to bring a pressure measured by a pressure sensor closer to a target pressure determines a current state and a reward for an action selected in the past based on a difference between the measured pressure and the target pressure, updates a control condition, which is a combination of a state and an action, based on the reward, selects an optimum action corresponding to the current state under the updated control condition, and controls the rotation speed of the pump based on the optimum action.

In an extrusion molding apparatus according to an embodiment, a control unit configured to perform feedback control for a rotation speed of a pump so as to bring a pressure measured by a pressure sensor closer to a target pressure determines a current state and a reward for an action selected in the past based on a difference between the measured pressure and the target pressure, updates a control condition, which is a combination of a state and an action, based on the reward, selects an optimum action corresponding to the current state under the updated control condition, and controls the rotation speed of the pump based on the optimum action.

One or more embodiments of the present invention provide an apparatus for applying a mixture of a first compound and a second compound, the apparatus comprising a first extruder for processing a first compound and a second extruder for processing a second compound, wherein the outlet from the first extruder is in fluid communication with a first channel of a housing, and the outlet from the second extruder is in fluid communication with a second channel of the housing, wherein a gear pump is positioned in each channel, wherein a nozzle is in fluid communication with an outlet of the first channel and an outlet of the second channel, and a coextruded continuous strip is produced. The ratio of the first compound to the second compound may be adjusted instantaneously.

One or more embodiments of the present invention provide an apparatus for applying a mixture of a first compound and a second compound, the apparatus comprising a first extruder for processing a first compound and a second extruder for processing a second compound, wherein the outlet from the first extruder is in fluid communication with a first channel of a housing, and the outlet from the second extruder is in fluid communication with a second channel of the housing, wherein a gear pump is positioned in each channel, wherein a nozzle is in fluid communication with an outlet of the first channel and an outlet of the second channel, and a coextruded continuous strip is produced. The ratio of the first compound to the second compound may be adjusted instantaneously.

A continuous cycle system for moulding single objects from plastic material, including: an extruder including a cylinder extending along a longitudinal axis (L), a screw rotating inside the cylinder about the longitudinal axis (L), the screw having a core and a thread externally coupled to the core and heaters coupled to the cylinder; a moulding machine, configured to receive as input the flow of liquid plastic material from the extruder and including a plurality of moulds, each having a first and a second half mould movable relative to each other between an open position and a closed position.

A system for adjusting a gap in a slot die for producing a polymeric web. The system includes a slot die that has a polymer reservoir that extends between a polymer inlet and a melt outlet. The melt outlet has a first edge and a second edge that each extend longitudinally along the melt outlet. The second edge is opposite the first edge. A plurality of actuators move the second edge along a plurality of positions along a length of the second edge. The first edge is spaced apart from the second edge by a gap that has an adjustable profile. A pressure sensor communicates with the reservoir and measures the pressure of the polymer in the reservoir. A control unit with an algorithm correlates the profile of the gap to the pressure in the reservoir. The algorithm is configured to generate control signals to cause the profile of the gap to be uniform.