ESD STANDARDS

OBJECTIVES

The materials manufactured by Fagor Automation are of the "ESD - Electrostatic Sensitive Device" class, which implies that the SNC has laboratories that comply with "ESD" specifications.

"ESD" laboratories are intended to increase reliability, avoiding problems, during and after repair, as explained below.

Static electricity is a major cause of breakdowns in electronic equipment, often invisible, difficult to diagnose and may even manifest only several days after discharge. It is imperative for the quality increase to exist a control of this type of events and to minimize them to the maximum. Static electricity results from electric charges generated by friction - triboelectric, namely people walking, fluids moving in a tube, etc.



Loads are accumulated on the surfaces of objects and people,and can have high values.


According to the above table it can also be verified that the relative humidity of the air helps to dissipate this type of energy.

A summary provided in the literature and which should be retained:

  • 1. Virtually all materials, including conductors, can be triboelectrically charged.
  • 2. The amount of accumulated load depends on material, speed of contact and separation, humidity and many other factors.
  • 3. Loaded objects have electrostatic fields.
  • 4. An electrostatic discharge can immediately or catastrophically damage the equipment, or it may become latent and only be detected later, that is, it will shorten the life of the equipment.
  • 5. Electrostatic discharges may occur during the manufacturing, testing, transport, handling, operation or during the final service.
  • 6. Discharge can occur either from the equipment or the equipment or through electrostatic fields. Sensitivity depends on the equipment.

    • To control these electrostatic charges, it must be defined which equipment is sensitive and the places where the manipulation rules of such equipment will be applied.

    In defined areas, the quantity of loads produced must be minimized and techniques for unloading can be avoided. In this way, the ESD project should contemplate the definition of demarcated rules and zones and the people training. One of the basic principles that must be followed is to put all materials and people to the same potential, linked by mats, bracelets, etc.., if there is no potential difference there will be no discharges.

    Definitions

  • 1- ESD - electrostatic sensitive device.
  • 2- Sensitive equipment or components:

    • In general, all equipment that does not have its own metal box or box is open and that allow you to play directly on the circuits and electronic components.

    They are also components that are already inside packages that are identified with the symbol:

    TRIBOELETRIC - The creation of electrostatic charge by contact and separation of materials is known as "triboelectric." The word "triboelectric" comes from the Greek words, tribo - meaning "rub" and elektros - meaning " 'amber' (fossilized resin from prehistoric trees). It involves the transfer of electrons between materials.

    The atoms of a material without a static charge have an equal number of (+) positive protons in their nucleus and negatives to orbit the nucleus. In Figure 1, the material "A" consists of atoms with equal numbers of protons and electrons. Material B is also composed of atoms with equal (though perhaps different) numbers of protons and electrons. Both materials are electrically neutral.

    When the two materials are brought into contact and then separated, the negatively charged electrons are transferred from the surface of one material to the surface of the other material. Which material that loses electrons and what material does the electron gain? It will depend on the nature of the two materials. The material that loses electrons becomes positively charged, while the material that gains electrons is negatively charged. This is shown in the figure above.

    AREAS OF INTEREST IDENTIFICATION

    The areas of ESD interest are spaces where there are tools, means and conditions that minimize the presence of electrostatic charges and where every effort should be made to keep this level low.

    In these areas it is safer to handle and open packages containing sensitive equipment. These areas are marked with the symbol:

    Proximity alert symbol to the handling area of ESD-sensitive equipment

    Oporto’s Lab - Access by room 214

    Oporto’s Lab - Access to the lab

    Oporto’s Lab - Access by room 212

    ALSO SHOULD BE DELIMITED BY THE TAPE:

    ESD zone boundary tape

    ESD mat in laboratory Marinha grande delimited by ESD zone delimiting tape

    Access to Marinha grande’s Laboratory - ESD zone input indicator tape

    ESD mat in Porto’s Laboratory delimited by ESD zone delimiting tape

    ESD walk-through mat in Oporto’s Lab

    Access to Oporto’s Lab - ESD zone input indicator strip

    These areas of interest should be monitored for relative humidity which should not be less than 50% nor more than 90%.

    IDENTIFICATION OF PERSONS OF INTEREST

  • • Technicians - people who can handle sensitive boards and components
  • • Packers or receivers of materials - must take precautions when handling sensitive equipment or components
  • • Cleaning Service - The cleaning service must be informed of the following:
  • - You are not authorized to manipulate, touch, divert any material within the ESD area.
  • - You can clean all areas free of materials.
  • - You cannot use strong products in ESD countertop and carpet cleaners, you should only clean with water without adding any product, to avoid damage to the materials.
  • - Whenever you find materials on work benches, you are not required to clean the workbench, this task is the responsibility of the technical service.
  • - When the workbench is free of materials, it can perform cleaning services.

    • IDENTIFICATION OF TOOLS NEEDED

    The following needs were identified following the field survey:

  • • Workstation

    • The work station handling sensitive equipment should be composed of carpets on the countertop and floor to dissipate electrostatic energy. They must be properly grounded securely.

    Workstation mat

    ESD connection point

    Clothing - Operators must be equipped with clothing to assist in dissipating electrostatic charges, in particular work gowns, shoehorn and bracelets.

    ESD Clothing

    Clothing must be stored in a visible place and easily accessible outside the ESD

    Place of work gowns in Marinha Grande

    Number of people expected in the laboratory: 2

  • Work Tools

    • The cleaning equipment operations must take into account the generation of loads. Appropriate brushes should be used.

    Work tools, welding stations, and hand tools should promote the disposal of electrostatic charges.

    Quantity Description
    1 Electronic workstation
    1 ESD walk-through mat per passage
    1 Relative Humidity Meter

    IMPLEMENTAÇÃO

  • 1. Delimitation of ESD zones according to attached project
  • 2. Identification of areas with signs
  • 3. Installation of ground and floor mats on bench and floor
  • 4. Definition of the place to store clothing
  • 5. Location definition of ESD tools
  • 6. Training of persons of interest

    • Rules

  • 1. Being in an ESD area requires:
  • a. Be dressed in appropriate clothing
  • 2. Working in an ESD area requires:
  • a. Be in the proper clothing
  • b. Wear Electrostatic Bracelet
  • c. Use the shoehorn
  • d. Use ESD tools
  • 3. Handling of sensitive equipment
  • a. The presence of sensitive equipment in good working order or repairable outside ESD areas is prohibited.
  • b. Sensitive equipment shall be properly packed in suitable packaging to be stored outside sensitive areas or to be transported.
  • NOTE: Closed metal boxes equipment is not considered to be sensitive equipment.

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