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Ability of removal of particles beyond the limits of the visible world of the microscope
 1.
Concept (for the applications on tape)
A patented system to alternate cycles of aspiration and ultrasonic jam, arranged with an emission of ultrasounds to most vhf, concurs to obtain one cleaning without equal. New device UVU-W is the dry system of cleaning to more effective currently in commerce.
2. Characteristics and advantages
(1) Total removal of particles of the maximum largeness of 1,6µm.
(2) The numerous produced peaks of wave from the generating multiwave to ultrasounds, bind together to a level of the maximum emission of 132,8 dB, contribute to the removal of particles to prescind from their dimensions.
(3) The flow of turbulence provoked from the collision of the ultrasonic waves concurs to break off the boundary layer and to separate the trapped particles.
(4) The bidirectional air flow removes particles in an effective way, to prescind from their guideline on the tape (to see Fig. 2)
(5) The ability to the Shinko to produce high technology devices has concurred the realization of a thinner and uniform nozzle that conserves high rigidity. This technology concurs to reduce lessened the demanded swallowing capacity and to maintain to constants the cleaning performances along all the active surface of the device.
3. Principle
The cleaning heads are planned with two ultrasonic pressure nozzles and a wide fissure of aspiration for the removal of particles of small and great dimensions (to see Fig. 1)
The two high pressure nozzles produce an high speed air effect for the removal of particles of greater dimensions, comprised between 50 and 100 micron. These particles come subsequently inhaled in the fissure of aspiration from both the removed directions and therefore removed. However, on the surface of the tape is created a viscous boundary layer, because the air comes sprayed to high speed above the viscous layer. The ultrasonic pressure makes pulse the particles separated to us and confined in the viscous layer. In other words, the energy of the transferred ultrasonic pressure in the air flow to high speed breaks off the boundary layer in order to free small particles from the surface of the tape.
The very small particles, therefore like particles of greater dimensions, come ready aspired from the head of aspiration after have been separated from the surface of the tape thanks to the effects combined of air and the ultrasounds waves and removed from an exhaust fan to high speed (to see Fig. 2)
4. Examples of the results of the cleaning tests
Test 1
Material: film
in PET, Particles: fluctuating particles, In line Speed:
200 m/min.
Evalutation:
Before the cleaning it has been sampled and tested the number of particles present on a film and compared with the one taken after the cleaning. The result determinates the cleaning performances. The results are evidenced in the working sheet.
Results:
The performances of cleaning are determined to the equation (1) that calculates the relationship of removal of particles.The result of the test is indicated in Diagram 1..
Grafico 1. Sum CNT indicates the number total of counted particles.**COUNT**
indicates the particle number for dimension.
Test 2:
Material: glass for LCD (250 milimeter x 250 milimeter x 1.1 t) Particles: silicone spacing moldings from 1,6 micron Speed of line: 50 mm/sec.
5. System of canalization and structure
Structure
The system consists of the cleaning head; compressors for the inhaled and compressed air; a filter HEPA for the cleaning of the compressed air; a prefilter, a rough filter that collects removed particles; dampers in order to control the inhaled and compressed air; links in order to connect the components.
Closed loop system
A single compressor replaces in circle the air through the cleaning head and two filters. This closed loop system does not influence on the equilibrium of the air in the working areas, like as an example powder isolated atmospheres, but it contributes to reduce the operating costs. The system could not be appropriated for the sensitive tapes to the temperature, since the temperature of the air in circulation comes increased regarding the ambient temperature.
System to open cycle
There are used independent compressors for the inhaled and compressed air, that produce less sensitive increases of temperature on the surface of the tape.
Options
For a better performance and effectiveness, the following options are available:
- Ionization system
- Cleaning head raiser
- Jam module (single unit containing the compressor and the filters)
- Powder binder (much profit in the removal of great amounts of particolates )
- Cooling system
- Acoustic isolation
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