Method and apparatus for producing a wound package of an endless thermoplastic material

A method of processing a continuous thermoplastic material while monitoring its quality, and comprising the steps of

• advancing the continuous thermoplastic material along a path of travel,
• winding the advancing thermoplastic material into a package,
• monitoring continuously the diameter of the package while it is being wound,
• continuously calculating the square of the measured diameter, and continuously calculating the time derivative of the square of the measured diameter,
• generating a control signal which is a function of said time derivative,
• comparing the control signal with a predetermined reference signal, and
• generating an output signal at least during periods when the difference between the control signal and the reference signal exceeds a predetermined deviation, and such that the output signal represents the quality of the continuous material in the wound package.

A method of processing a continuous thermoplastic material while monitoring its quality, and comprising the steps of

• advancing the continuous thermoplastic material along a path of travel,
• winding the advancing thermoplastic material into a package,
• measuring the surface speed and the rotational speed of the package, so as to permit the package diameter to be calculated
• generating a control signal which is a function of the diameter,
• comparing the control signal with a predetermined reference signal, and
• generating an output signal at least during periods when the difference between the control signal and the reference signal exceeds a predetermined deviation, and such that the output signal represents the quality of the continuous material in the wound package.

A method of producing a plurality of strands of continuous thermoplastic material while monitoring the quality of each strand, and comprising the steps of

• extruding a thermoplastic material so as to form a plurality of separate strands,
• advancing each of the strands along a separate path of travel,
• winding each of the strands into a separate package,
• monitoring a physical parameter of each of the packages while it is being wound, and including generating a control signal for each of the packages which is a function of the monitored physical parameter,
• calculating the mean value of the control signals,
• comparing the control signal of each of the packages with the mean value, and
• generating an output signal at least during periods when the difference between the control signal and the mean value for a package exceeds a predetermined deviation, and such that the output signal represents the quality of the strand of thermoplastic material in the associated wound package.

A method of producing a continuous thermoplastic material while monitoring its quality, and comprising the steps of

• extruding a thermoplastic material from an extruder so as to form a molten thermoplastic material which advances continuously along a path of travel,
• passing the molten advancing material through a die which comprises a slot-like opening,
• cooling the advancing material after having passed through the die so as to solidify the material,
• winding the solidified advancing material into a package,
• monitoring a physical parameter of the package while it is being wound, and including generating a control signal which is a function of the physical parameter,
• comparing the control signal with a predetermined reference signal, and
• generating an output signal at least during periods when the difference between the control signal and the reference signal exceeds a predetermined deviation, and such that the output signal represents the quality of the continuous material in the wound package, and wherein the step of generating said output signal includes controlling the width of the slot-like opening as a function of the output signal.

A method of processing a continuous thermoplastic material while monitoring its quality, and comprising the steps of

• advancing the continuous thermoplastic material along a path of travel,
• winding the advancing thermoplastic material into a package,
• monitoring the weight of the package and the length of the continuous material advancing to the package while it is being wound, so as to permit the calculation of the denier of the continuous material advancing to the package, and including generating a control signal which is a function of the weight,
• comparing the control signal with a predetermined reference signal, and
• generating an output signal at least during periods when the difference between the control signal and the reference signal exceeds a predetermined deviation, and such that the output signal represents the quality of the continuous material in the wound package.

A method of processing a continuous thermoplastic material while monitoring its quality, and comprising the steps of

• advancing the continuous thermoplastic material along a path of travel,
• winding the advancing thermoplastic material into a package,
• monitoring the weight of the package while it is being wound, and including generating a control signal which is a function of the weight,
• comparing the control signal with a predetermined reference signal, and
• generating an output signal at least during periods when the difference between the control signal and the reference signal exceeds a predetermined deviation, and such that the output signal represents the quality of the continuous material in the wound package,
• applying a liquid finish to the advancing continuous material before it is wound into the package, and wherein the monitoring step includes monitoring the weight of the package and the weight of the liquid finish applied to the advancing material, and
• wherein the step of monitoring the weight of the liquid finish applied to the advancing material includes measuring the weight of the advancing material before the liquid finish application per unit of time, and subtracting the measured weight of the advancing material before the liquid finish application per unit of time from the weight of the package per unit of time so that the difference equals the weight of the applied liquid finish per unit of time.