313 Каталог HOFFMANN GROUP 2020 Промышленные средства индивидуальной защиты Стр.313

Каталог HOFFMANN GROUP 2020 Средства индивидуальной защиты Стр. 313 0313 Lab2u

SGD Hoffmann Group 51 INFORMATION ABOUT ESD PROTECTION Explanation of terms: ESD stands for Electrostatic Discharge. A spark or a breakdown is caused by a large difference in potential, and produces high electrical voltage pulses in electronic equipment. ESD = Electrostatic Discharge Electrostatic discharge between charged objects through direct or close contact. ESDS = Electrostatic Discharge Sensitive Devices Devices which can be damaged by electrostatic discharges when being used or transported. EPA = Electrostatic Protected Area A work area fitted with ESD protection measures where electrostatic sensitive devices can be handled without being damaged. Electrostatic charges Pictograms: arise for instance due to: Walking across plastic flooring /'T\ Symbol for a a Warning symbol for m Friction against synthetic clothing () component that requires ESD sensitive devices, m Moving plastic containers ESD protection. m Unrolling sticky tape Moving conveyor belts For a human to perceive static discharge, it needs to have reached around 3,000 volts. In comparison, just 30 volts is enough to destroy a semiconductor device. Uncontrolled electrostatic discharges can lead to total failure as well as hidden defects in electronic assemblies (semiconductor devices), which can result in high costs. ESD clothing - product protection for ESD sensitive devices Where ESD sensitive product parts (such as in electronics production) may be damaged by electrostatic discharges from personnel, ESD clothing that will reliably dissipate electricity is required. In the past, personnel wore clothing predominantly of 100% cotton; this natural fibre has a very low ability to hold a charge. This characteristic does however depend on the atmospheric humidity. In dry air the fibres lack moisture and lose their natural capacity to dissipate electricity, so there is a risk that they build up a hazardous charge. For this reason, special ESD clothing with integral carbon fibres is preferred. The carbon fibres minimise the resistance and promote controlled dissipation of electric charges. EN 61340 Protection of electronic components against electrostatic phenomena Protective work wear certified to this standard is suitable for the manufacture of products that are sensitive even to low voltages of 100 Volt or more. Persons wearing ESD work wear protect such products in manufacture against electrical discharges that damage components. Clothing that is not suitable for an ESD environment can generate static electrical charges due to friction, influences (magnetic fields, effects of fields) or separation of materials. Comprehensive protection in all areas Workstations and storage - Vol. 3 Floor Markings Work place / Workstation An ESD protected work place should be ergonomically adaptable. Electrostatic charge is dissipated via the working area and a grounding cable, so the work place remains charge-neutral. Chairs and standing stools should also have ESD protection. Storage containers Dissipative ESD shelves and containers for transporting and storing devices protect at-risk devices. Roller cabinets should have conductive wheels. The floor should be conductive and meet the required limits of DIN EN 61340-5-1. When cleaning ESD floors, use only cleaning products that do not create layers, so that the conductivity values remain within the desired range. If only individual workstations are set up as EPA, ESD floor mats or tiles can be fitted with grounding, but they must be clearly marked. Floor markings identify ESD protected areas. Signs and stickers are equally important in signalling potentially at-risk devices and assemblies. Hand tools and metrology - Vol. 2 Measuring It is essential to test protection devices regularly using measuring equipment. Measurements must always be taken when entering an EPA and regular personnel checks must be performed. Work tables, floor mats and grounding connections should be checked monthly and ESD monitoring instruments should be checked annually. The discharge resistance should have the following values: Work surfaces: between 7.5x10s 0 and 109 0 Floors: less than 109 0 Chairs/standing stools: less than 1010 0 Tools: less than 1012 0 Tool To ensure safe handling of your devices you should use ESD-compliant tools. Personal protective equipment - Vol. 4 Personnel grounding People are the main source of electrostatic charges. Shoes and wristbands with grounding cables are mandatory for employees working in electronic production. ESD gloves and clothing are no substitute for personal earthing using a wristband, but they should prevent a build-up of charge and prevent any sharp discharge. Wristbands can be found in Vol. 3 Workstations and Storage. 313