Resistance Measurement of Antistatic Clothing Used in SMT Production Lines
In SMT (Surface Mount Technology) electronic component placement, static electricity is generated due to the rapid movement of components during the high-speed operation of the placement machine. The static voltage is approximately 600V. This static electricity leads to performance degradation of components and can even indirectly affect integrated circuits, causing them to malfunction.
Antistatic clothing is an essential antistatic item in SMT production to reduce static electricity generated by the human body. It is made of conductive metal wires (such as stainless steel wire) blended with cotton, synthetic fibers, etc., and some are made of carbon fiber or conductive synthetic fibers (such as copper complex fibers). When rubbed against other objects, the generated static electricity is leaked through contact with the human body via the conductive fibers or dissipated through corona discharge between the conductive fibers, thus preventing static electricity accumulation.
However, wearing antistatic clothing does not mean that static electricity is completely controlled. If the antistatic effect of the clothing is achieved through dyeing, then such antistatic clothing is no different from ordinary clothing and may even accelerate the generation of static electricity. Resistance testing of antistatic work clothes can verify whether the clothing complies with the requirements of GB12014-89 "Antistatic Work Clothes" by measuring the resistance value point-to-point. First, the antistatic work clothes must be placed on an insulating table with a surface resistance of at least 10¹⁴ Ω and the table must be large enough. Point-to-point resistance measurement should be performed at least at three different locations, including the seams of the garment. A weighted surface resistance meter (ACL-800) should be used. The distance between the two electrodes of the meter should be no less than 300 mm, and the axis connecting the two electrodes should be opposite to the axis of the garment fibers.