Printed wiring flexible

Flexible printed wiring laminates usually contain (but are not limited to) either a polyimide or a polyester [usually poly(ethylene terephthalate)] with copper conductors. These laminates are prepared in sheets or by roll-to-roll lamination, usually by means of an adhesive. Alternatively, direct fusion without an adhesive is used. Recent developments include the use of alternative substrate materials such as poly(ether sulfones), additive plating of copper, and casting of a polymer directly on the copper foil web. 

IPC-6202, IPC/JPCA Performance Guide Manual for Single- and Double-Sided Flexible Printed Wiring Boards ... 

IPC-FC-231C Fiexible bare dielectrics for use in flexible printed wiring... 

JIS-C 5016 Test methods for flexible printed wiring boards... 

JIS-C 5017 Flexible printed wiring boards, single-sided and donble-sided... 

Both rigid and flexible printed wiring are further classified according to structure of which there are three basic types, as illustrated in Fig. 9.3 ... 

Flexible printed wiring is used primarily in electronic packaging applications where low weight or volume is a prerequisite, or excessive vibration is likely to be encountered. The main advantage of flexible circuitry is its ability to be shaped into more than one plane or conform to an irregular shaped package. 

The development of flexible printed wiring was made possible through the availability of plastic films that possess high electrical insulation and good chemical resistance, in particular polyethylene terephthalate and polyimide films which account for over 95% of the flexible film consumption for printed wiring applications. The properties of the most important of these polymers are discussed in the following sections. 

These resins have extensive appHcations in the high performance insulation markets (traction motor, wire cable) and flexible printed circuits. Du Pont supphes Kapton film and also suppHes Verpel stock shapes made from the same resin by powder sintering methods. 

At the present time they are used for a variety of electrical and chemically resistant mouldings, for corrosion-resistant linings, for coatings, for flexible printed circuits and for wire insulation. One particular growth area arising from... 

Manufacture of Printed Wiring Boards. Printed wiring boards, or printed circuit boards, are usually thin flat panels than contain one or multiple layers of thin copper patterns that interconnect the various electronic components (e.g. integrated circuit chips, connectors, resistors) that are attached to the boards. These panels are present in almost every consumer electronic product and automobile sold today. The various photopolymer products used to manufacture the printed wiring boards include film resists, electroless plating resists (23), liquid resists, electrodeposited resists (24), solder masks (25), laser exposed photoresists (26), flexible photoimageable permanent coatings (27) and polyimide interlayer insulator films (28). Another new use of photopolymer chemistry is the selective formation of conductive patterns in polymers (29). 

Processing PCTFE is by the conventional methods (extrusion, injection, etc.) processing temperatures are high, and any degradation of PCTFE can cause severe corrosion and environmental problems. Applications include wire and cable insulation, electronic flexible printed circuits, packaging material (transparent film and sheet), pharmaceutical industry in particular strip and blister packs for tablets and capsules, etc. In the chemical industry, used as gaskets, 0-rings, valve seats, chemical tank liners, etc. 

Electrical insulation, wires and cables, flexible printed circuits, ultrapure components for semiconductor manufacture, condensers, batteries, barrier films for packaging of sensitive electronic parts, films for photovoltaic modules... 

Electrochemistry is a central theme in the interconnection of chips and other microelectronic components. The manufacture of printed wiring boards, such as single-layer, multilayer, or flexible boards, involves electroplating of the conductor that forms the electrical paths. The corrosion of these paths and the interfacial stability of the conductor-polymer composites that determine the reliability of these interconnections are electrochemical problems. 

Besides this prime role of attachment, electrically conductive adhesives are widely used to form electrical contacts between components and the printed-wiring board or other interconnect substrate, such as thin-film or thick-film ceramic substrates or flexible cable. For this function, adhesives serve as low-cost alternates to wire, solder, and other metallurgical connections. 

Polyurethane adhesives are used primarily in the assembly of printed-wiring boards to attach large components such as capacitors, magnetics, heat sinks, and connectors. Their key benefits include flexibility, absorption of stresses, vibration damping, and thermal transfer. Being thermoplastic, polyurethanes are also easier to rework than epoxies. 

The number of equivalents of the polyol is 0.58, so the amount of the isocyanate required to react in a 1 1 ratio will be 111 grams. The more flexible polyurethanes used in printed-wiring board applications generally employ polyols that have lower hydroxyl contents. 

This elastomer finds many applications in the electrical industry as wire and cable insulation and jacketing plenum cable insulation, oil well wire and cable insulation logging wire jacketing and jacketing for cathodic protection aircraft, mass transit and automotive wire cormectors coil forms resistor sleeves wire tie wraps tapes, tubing and flexible printed circuitry and flat cable. 

Film Applications Film for tape automated bonding (TAB) applications, flexible printed circuits (FPCs), insulation stirrer automotive wiring harness, bar code labels, aerospace, gas connections, fire gloves, and loudspeaker vibration boards. 

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