Gauging and profile control

Transcription

1 Gauging and profile control

2 Gauging and profile control SYNCRO measuring systems have been developed in order to meet with the most different requirements in all those processes which require a repeatable measuring and an accurate control of the thickness, such as: Blown film Cast film Extrusion sheet and thermoforming Bi-oriented film Spunbonded fabric Extrusion coating PVC calendering is a member of the SYNCRO family of measuring systems. is composed of a mechanical scanner suitable to measure film of different widths and is equipped with microprocessor electronics with Ethernet network interface. Equipped with film supporting cylinder on board the scanner and 17 touch-screen computer. uses a traditional instrument for the thickness measuring by means of Beta-emitting radioisotopes, such as Krypton 85 (up to 1000 gr./m 2 of unitary weight) with a low dosing (10 mci) of radioisotope Kr85. The low-dosing system is composed of: Sparking detector Converter of incident Beta energy into pulses of visible light PMT (Photo Multiplier Tube), converter of incident light into electrons. The PMT is polarised with a negative voltage comprised between 600 and 900 Vcc and its output is digitalised by a 16-bit converter (ADC) controlled by microprocessor. Measuring precision during scanning : ± 0.1 0,5 gr./m 2.

3 fis a member of the SYNCRO family of measuring systems. is composed of a mechanical scanner suitable to measure film of different widths and is complete with microprocessor electronics with Ethernet network interface. Complete with film supporting cylinder on board the scanner and 17 touch-screen computer. is based upon a largely used working principle, such as the inductive measuring system of the distance. The solenoid placed into the upper measuring head represents an element of a free-frequency oscillating circuit, which is realised in a microprocessor electronic card. The circuit oscillation frequency depends on the magnetic reluctance of the environment close to the solenoid; the lower head includes a small ferrite which, if it is placed close to the solenoid, increases its magnetic reluctance, thus reducing the oscillation frequency. Consequently, the variation of the distance between solenoid and ferrite produces a frequency variation linked to the distance between the two elements. If the distance between the two detecting elements is represented by the thickness of a film, the result is a thickness measuring. Both measuring heads are equipped with compressed air nozzles with a particular patented geometry, which produces an air cushion having a constant thickness between heads and film so as to allow the belt movement without the contact of the heads and without marking the extruded product. Measuring precision during scanning: < 1 µm. is the automatic supervision and control system for the thickness of SYscan which controls the temperature of the cartridge heaters placed into the flat die, thus changing the profile of the extruded product in order to obtain flat reels.

4 Gauging and profile control Also, and are members of the SYNCRO family of measuring systems. They are dedicated and designed systems for blown film lines. is a simple measuring system for blown film line. is based on the capacitive technology and provide a continuous thickness measure during the process. It can be installed either stand alone on the collapsing frame or on an oscillating ring connected to an auto profile control. is a simple system which uses the inductive measuring method to obtain the profile of the blown film line. is installed after the haul-off unit and measures the thickness of one edge of the flat film, thus obtaining the complete profile whenever the take-off unit oscillates. is composed of two measuring heads SYhead. is installed after the haul-off unit and measures the thickness of both edges of the flat film, thus obtaining the complete profile whenever the take-off unit oscillates by half.

5 finds a special application in blown film installations. Installed after the haul-off unit, thanks to a new patented software and calculation method,, starting from a double flattened film is able to discriminate the two layers after few scannings and to exactly measure all the points on a 360 circumference. After obtaining the first profile, provides a profile almost with each scanning, that is to say, every 30/60 seconds (it depends on the lay-flat of the tubular film). Thanks to the high measuring speed, is suitable for the integration with an automatic profile control system, either with cartridge heaters into the die or with air flows into the air cooling ring but also with other techniques available on the market. ~ 12 min. ~ 6 min. ~ 2/3 min. ~ 30/60 sec.

6 Gauging and profile control For the automation of blown film process, SYNCRO developed manual and automatic control systems for the thickness profile based on SATURN hardware technology. is the duallip cooling ring with patented concept, the function of which is to offer a fine adjustment of the air volume of the lip set to find the particular characteristics of the extruded polymer. Características: Adjustable lips Adjustable forming cone 6/8 air inlets Interchangeable lip set Aluminium casting manufacture

7 is the easiest and the cheapest control system for the profile: by simply integrating a segmented disk with the standard air ring, it is possible to manually adjust the air flow in the different segments thanks to dedicated screws. The operator, after checking the film thickness off-line, can adjust the opening of every single gap of the segmented disk and regulate the air flows, thanks to which the profile is regulated. It is particularly suitable for those installations which do not require a frequent production change. can be combined with the on-line thickness measuring system SYhead, so that the operator can avoid using a sample of the film extruded in the laboratory to obtain the profile and can speed up the adjustment and correction operations. is a completely automatic system by SYNCRO for the on-line thickness profile control. The air flows of the segmented disk integrated into the air ring are controlled by stepper motors which adjust the opening/closing of the gates. The thickness measuring system is integrated into the supervision software and supplies with the measured profiles. When measuring a point having a thickness higher than the set tolerance, the stepper motor will decrease the air flow into the corresponding segment, thus reducing the film thickness, while, when measuring a point with a thickness lower than the tolerance, the air flow is increased in order to increment the thickness.

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