Wednesday, January 26, 2011

【 Weak current College 】 how cleaning and testing anti-static clothing 】

Anti-static overalls are applicable to the electronic, optical instruments, pharmaceuticals, microbial engineering, precision instruments and other industries have clean and antistatic properties of special overalls, the material is generally the conductive wire embedded in woven fabrics of synthetic fibers, clean uniform management of the most important aspect is the clean, although the fiber itself is very difficult to get dirty and clean fiber, but how to maintain is an important factor, that is the method used for cleaning. If using ordinary washing method, of course, on the contrary will be dirty. You must use a special method. Clean clothes, from management, cleaning time must also be in a clean room cleaning confessed little 飾 packaging. Normally clean washing of clothes at least once a week, some demanding trades or even washing every day. In a normal room cleaning, dust and bacteria attached, as well as cleaning agent of pollution. In addition, the packaging and handling process, will be attached to the risk of dust and micro-organisms. Clean working clothes cleaning is generally rely on professional cleaning company for cleaning.

First, the cleaning process should be aware of

(1) a new sewing clean washing of clothes may direct, but recovery through the discovery of oil pollution clean uniform, carefully removing the greasy dirt to washing program.
(2) washing before on chafed, damage and buckle, and other accessories for inspection of defective to repair, replace or scrap.
(3) must be used in the ratio of Workwear Cleanroom cleanliness of clean room for washing, drying and packaging.
(4) wet and dry cleaning of water filtration, solvents are distilled on the point of use after use is less than 2 μ m aperture of membrane filters, make the filter more than once.
(5) in order to remove soluble pollutants, washing with water, then uses the distillation of solvents for the last washing to remove oily pollutants.
(6) wet washes the water temperature is as follows:
Polyester cloth 60-70C (highest 70C)
Nylon 50-55C (highest 60C)
(7) in the final rinse water permeability, can be used to improve the anti-static antistatic characteristics, but selection of antistatic agent should be combined with the fiber is good, no dust particles.
(8) the uniform of a buckle, fastening State washing.
(9) in the washing dedicated clean air circulation system for drying.
After drying, cleaning in washing dedicated indoor fold, Mount clean nylon polyester bag or, on request, double packaging can also be vacuum molding, packaging materials, preferably with antistatic material with good. Due to the collapse process most prone to dust, folding processes must be in the high level of purification space, such as a class 100 clean overalls folding packing should be in the 10-level environments.

II. performance testing of clean overalls

1 purifying performance testing

On clean indoor use clean cloth and clothing for the attachment of pollution particles, with the following four methods: ASTM F-51 method (microscopy), F-51 between Buddhist ideas method (count), HELMKE drum (drum method, ASTM test method), and vibration test method (vibration).

(1) ASTM-F-51 method (microscopy)
Test probe with filter diaphragm, direct connect suction pump, by the amount of air to 28L/min. Testing the air through the test material, will air in the dust particles caught testing of filtration membrane, with 400 x microscope and statistical dust particles. Read out the filter above 0.5-5 and 5 above the number of particles. In the filter above printed 3.08mm lattice, can read out a number of particles within the lattice.

(2) amendments to the law ASTM-F-51 (counting)
The air through the test material, with particle counters for the determination of a dust particle size and number. The sample is placed in the with metal net-bench, sampler (47mm filter bracket in place), by the amount of air to 28L/min.

(3) barrel (HelmkeDrumTest)
The sample is put into a side openings of the rotating roll drums rotate, the grain of drums on dust particles sampled with particle counters for the determination of particle number cleanliness level after the decision. Rotating drum size 43cm×33cm, the inside of the barrel was 4 blades, buckets of speed to 10 RPM.

(4) vibration method
The sample is placed in a small room, through the vibration of reversing the particle production, determination of the particle counters. At the same time, the size of large particles (25 or more) trap to filter membrane, read out the number of particles. Air volume 3.5 ft/min (0.099m/mim), vibration frequency of 150 times per minute.

Currently in clean and dust-free performance test Workwear has yet to have a national standard, refer to Japan air cleaning Association specialized Committee of Japan industrial standard JIS-B-9923, and United States RP-CC-003-87-T IES standards. For dust-free performance evaluation, the industry according to international standard ISO/TC209 under clean room standards, combining their respective clean grade a distinction between use.

2 antistatic performance testing

Antistatic sex is an important clean uniform characteristics, especially in the microelectronics industry on the clothing of antistatic performance requirements more stringent. Test method can People's Republic of China national standard GB/T12703-91 textiles static testing method, because the clean working clothes is embedded in the fabric is woven polyester conductive silk filament fabric, so the standard only friction-charged voltage (B), charge density (C) and the overalls of friction-charged (E) suitable clean working clothes of antistatic performance testing. In addition can also reference People's Republic of China national standard GB/T12059-89 the electronic industrial synthetic antistatic silk performance and experimental methods.

(1) friction-charged voltage method
The method of measurement principle is a certain tension conditions, so that the sample and standard cloth mutual friction, to this point have the highest voltage and average voltage on dress and coat the evaluation of friction-charged relationship. Its approach is to use the specimen (block of 4, 2, 2-up, size 4cmX8cm) clips over drum (diameter 150 ± 1mm, width 60 ± 1mm) sample clip card, drum to 400rpm speed and standard cloth (nylon or polypropylene) friction, testing the sample live 1min voltage Max (V).

(2) charge-density method
Specimens in the provisions of the conditions in a particular way and nylon fabric friction with the standard.

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