The present disclosure is directed toward a method for aligning a radiation head of a terahertz sensor system with a target surface. The method includes: scanning a selected area of the target surface with a terahertz radiation beam emitted by the radiation head; sensing a peak amplitude for each reflected radiation signal from a plurality of reflected radiation signals received by the radiation head during the scanning of the selected area; and identifying a normal position of the radiation head with respect to the target surface based on a maximum peak amplitude from among the peak amplitudes of the reflected radiation signals.

The extrusion apparatus includes a screw in a fixed barrel. The barrel has a feed inlet and an outlet with an extrusion nozzle which discharges into the nip between first and second rotary rolls that can rotate in opposite directions. The apparatus also has a first means for rotating and a first control means that are able to synchronize the speed of rotation of the first roll and the screw and has a second means that is able to rotate the second screw at a different speed of rotation than the first roll. The first control means can regulate the speed of rotation of the screw depending on the width of the strip, and a second control means can regulate the speed of rotation of the second roll depending on the thickness of the strip.

An adjustment system coupled to a die, and a die including an adjustment system, includes first and second adjustment modules. The first adjustment module includes a first body, a first plurality of studs, and a first actuator. Each of the first plurality of studs is slidably positioned within the first body. The first actuator is coupled to the first plurality of studs and is configured to move each of the first plurality of studs. The second adjustment module includes a second body, a second plurality of studs, and a second actuator. Each of the second plurality of studs is slidably positioned within the second body. The second actuator is coupled to the second plurality of studs and is configured to move each of the second plurality of studs. The number of studs composing the first plurality of studs is different from a number of studs composing the second plurality of studs.

Provided is a thickness variation adjustment-type air ring capable of accurately and optimally controlling the volume of cooling air at all positions in the circumferential direction, and stably manufacturing a synthetic resin film having an exceptionally low thickness variation. A thickness variation adjustment-type air ring is provided on a die of an inflation film manufacturing apparatus which locally controls the volume of cooling air discharged from a cooling air passage in a circumferential direction to adjust the thickness variation of a synthetic resin film when blowing the cooling air around a molten synthetic resin tube extruded in a longitudinal direction to cool and solidify the molten synthetic resin tube to form the synthetic resin film, the thickness variation adjustment-type air ring. The thickness variation adjustment-type air ring includes: a ring-shaped passage adjustment portion arranged sequentially in the circumferential direction inside of the cooling air passage; and a plurality of moving portions connected at a predetermined position in the circumferential direction of the passage adjustment portion so as to move a connecting portion of the passage adjustment portion in a predetermined direction independently from other portions, wherein a space in which cooling air can circulate inside the cooling air passage is locally adjusted in the circumferential direction and the volume of cooling air is locally controlled in the circumferential direction.

A polycarbonate resin includes a repeat unit represented by Formula 1; a repeat unit represented by Formula 2; and a repeat unit represented by Formula 3, wherein the polycarbonate resin has a weight average molecular weight of about 15,000 g/mol to about 60,000 g/mol and a melt index of about 3 g/10 min to about 40 g/10 min.: ##STR00001## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, a, b, c, and d are the same as defined in the specification. The polycarbonate resin for film can exhibit excellent scratch resistance, elongation, chemical resistance and heat resistance, and can be used to prepare a film in roll form without any protective film.

The invention relates to a method for switching the production of a flat film machine (100) from a feed product (EP) to a follow-on product (FP), comprising the following steps: recognizing a switching request for a switch from the feed product (EP) to the follow-on product (FP), determining a current feed control value (ES) of at least one control variable (SG) of the flat film machine (100) for the feed product (EP), determining a follow-on control value (FS) of the same at least one control variable (SG) for the follow-on product (FP), generating a control signal (SS) for a defined variation of the at least one control variable (SG) of the flat film machine (100) from the feed control value (ES) to the follow-on control value (FS).

Methods and apparatus for enhancing the flatness of a die by applying adhesive to a shim having a selected flatness, rotating the shim to spread the adhesive to a layer having a uniform thickness, evacuating a chamber to create a vacuum; manipulating a die onto the adhesive layer in the chamber; and reducing a level of the vacuum to pressure the die onto the adhesive layer such that the bow in the die is reduced as the die conforms to the shim.

A method of producing a blown film with a controlled thickness profile, comprises the steps of: extruding molten plastic through an annular extrusion die; cooling the molten plastic using an annular blower around the extrusion die, positioning one or more sources of supplemental air at one or more desired circumferential positions about the annular extrusion die and adjacent to the extruded molten plastic, the annular blower and the one or more sources of supplemental air being operated to supply cooling air to the molten plastic between the annular extrusion die and the frost line where the molten plastic solidifies; and controlling the one or more sources of supplemental air to form one or more areas of increased thickness along a circumferential thickness profile of the blown film, the one or more areas of increased thickness having a thickness that is greater than an average thickness of the circumferential profile.

The present invention may manufacture a composite pipe by forming an adhesive layer and a resin layer on an outer surface of a metal pipe, and although the composite pipe is wound in a ring shape after the composite pipe is manufactured, a circular cross sectional shape may be maintained without deformation, and after the composite pipe is straightened for the purpose of construction, separation or buckling may be prevented, resulting in excellent transportability and constructability of a product.

A film forming apparatus includes a die device which extrudes a molten resin in a tube shape to form a film, a measurement unit which measures a thickness profile of a film in a circumferential direction, a plurality of adjustment portions which change the thickness profile of the film, and a controller which controls the plurality of adjustment portions such that the thickness profile approaches a target thickness profile. The controller changes the target thickness profile based on the measured thickness profile.