Smooth Copper Foils, For Bus Bars, Transformer Connectors, Grade : ETP, OXYGEN FREE

Copper and aluminum foils are used as current collectors at the anode and cathode side. Both materials are highly stable with melting points >600°C (Table 7B.4). Accordingly, the current collectors do not contribute to the initiation of the thermal runaway of a cell, but at higher temperatures (>700°C) a thermite-style reaction between the Al and metal oxide of the cathode is in discussion. In the case of the copper foil, corrosion can lead to an internal short circuit caused by growing copper dendrites on the anode during deep discharge. 
Most stencils are fabricated from stainless steel, nickel, or copper foil 2–10-mils thick. Apertures are formed in the foil by one of three processes: chemical etching, laser cutting, or electroforming. Chemical etching, although the least costly of the three methods, provides the coarsest features. In chemical etching the apertures, the metal foil is coated on both sides with a photosensitive coating, exposed to UV light through a mask that has the desired aperture pattern, and developed. The part is then immersed or sprayed with a chemical etchant that removes metal only in the unprotected areas, after which the photocured coating is removed. With the trend toward finer pitch devices (less than 20-mil pitch), both laser-cut and electroformed stencils must be used. Laser-cut stencils can be produced directly from Gerber data by computer numerically controlled laser cutting. Aperture dimension tolerances of ±5 μm are reported. Chemically etched and laser-cut stencils are formed by subtractive processes. On the other hand, electroformed stencils are produced by an additive process in which a metal such as nickel is electroplated onto a mandrel that has a negative photoresist image of the aperture pattern. The electrodeposited nickel containing the apertures is then removed from the mandrel and used as the stencil. Because of their high precision patterns, electroformed stencils are used for ultra-fine pitch applications.
In recent years, there has been increased interest in stencils produced from plastics such as acetal and polyethylene. The prime benefit in using plastic stencils is the thicknesses that can be used (greater than 1 mm up to 8 mm). By drilling apertures of various sizes, adhesive deposits of different heights ranging from 0.2 to 2 mm were printed from a single screen thickness in one pass. Figure 4.4 shows a typical range of dot heights that were produced from a 1-mm-thick plastic stencil having aperture sizes from 0.6 to 2 mm. By carefully controlling the aperture size, it is possible to produce heights for every component type with a single squeegee stroke across a printed-circuit board 
Copper is an influential metal for both industrial and consumer applications. Our copper foil inventory consists of Electro Tough Pitch (110 alloy) and Oxygen Free (102 alloy). We also have copper foil sheeting and other copper foil sheet products that are Hot Tin Dipped to enhance solderability.
Copper is a versatile metal used in a variety of industries. Major characteristics include being a malleable and ductile metal with a very high thermal and electrical conductivity.
Copper foil is available in Alloys 110 and 102. Upon request, other alloys are also available. Its many applications include: roofing, structural engineering, EMI/RFI shielding, circuit boards, and heat exchanging. These copper coils can be supplied on fiber, aluminum, steel, and plastic cores with inner diameters up to 20”. Available tempers include annealed, full hard, and as-rolled.