OutlineThis procedure covers the suitable methods for handling circuit boards.Minimum ability Level - IntermediateRecommended because that technicians with an abilities in simple soldering and also component rework, however may be inexperienced in basic repair/rework procedures.Conformance Level - HighThis procedure most very closely duplicates the physical qualities of the original, and most probably follows all the functional, environmental and serviceability factors.
Handling digital Assemblies
IPC 7721/7721 2.1
Handling digital Assemblies
Electrostatic Discharge (ESD)Certain components used in electronic assemblies are sensitive to revolution electricity and can it is in damaged by its discharge. Revolution charges are developed when non-conductive products are separated, together as when plastic bags space picked up or opened, once friction wake up between short articles of man-made clothing, when plastic tapes space dispensed and many other causes.Destructive static charges room induced on adjacent conductors, together as human skin, and delivered in the type of sparks passing between conductors, such as when the surface of published board assembly is touch by a person having a static charge potential. If touched at the ideal solder share or conductive pattern, the circuit plank assembly can be damaged together the discharge passes through the conductive sample to a static sensitive component. That is essential to keep in mind that usually the static damages level for components cannot it is in felt through humans. (Less 보다 3,000 volts.)Electrical Overstress (EOS)Electrical overstress damages can be led to by generation of unwanted energy; such together spikes, developing within soldering irons, solder extractors, experimentation instruments and other electrically operated equipment. This tools must be designed regarding prevent unwanted electric discharges.ESD/EOS Safe work-related AreasThe objective of an ESD/EOS safe occupational area is to prevent damages to sensitive contents from spikes and static discharges. These locations must it is in designed and also maintained to avoid ESD/EOS damage.Handling and Storage MethodsCircuit plank assemblies must always be taken on at appropriately designated job-related areas.Designated work locations must be confirm periodically to ensure their continued protection. Locations of main issue include:Proper grounding methods.Static dissipation of job-related surfaces.Static dissipation the floor surfaces.Operation the ion blowers and ion wait guns.Designated work areas must be kept complimentary of static generating materials consisting of Styrofoam, vinyl, plastic, fabrics and also other static generating materials.Work areas must be preserved clean and neat. To prevent air pollution of circuit plank assemblies, there have to be no eat or cigarette smoking in the job-related area.When no being functioned on, sensitive components and circuit boards must be attached in shielded bags or boxes. There are three species of ESD security enclosure products including:Static Shielding - avoids static electricity from passing with the package.Antistatic - gives antistatic cushioning for digital assemblies.Static Dissipative - an "over-package" the has sufficient conductivity to dissipate any type of static buildup.Whenever dealing with a circuit plank assembly the operator have to be properly grounded by one of the following:Wearing a wrist strap linked to planet ground.Wearing 2 heel grounders and also have both feet ~ above a revolution dissipative floor surface.Circuit board assemblies should be handled by the edges. Avoid touching the circuits or components. (See figure 1)Components need to be tackled by the edges as soon as possible. Avoid touching the ingredient leads. Hand creams and also lotions containing silicone need to not be used because they can cause solderability and also epoxy adhesion problems. Lotions especially formulated to prevent air pollution of circuit boards are available.Stacking of circuit boards and also assemblies must be avoided to protect against physical damage. Unique racks and trays are obtainable for handling.