Self-adhesive solderable enameled copper wire
Solderable polyesterimide enameled wire enamels are widely used on the magnet wire of relays, small transformers, small motors, contactors, ignition coils, solenoid coils and automotive coils.
A polyesterimide wire enamel that can be soldered at temperatures above 450°C. These coatings are particularly suitable for small electric motors for connecting windings to commutators. The coated magnet wire has good elasticity as well as good dielectric and mechanical properties.
Adhesive magnet wire, also called self-adhesive magnet wire, is a thin film insulated wire coated with a thermoplastic adhesive. When activated, the thermoplastic linkage rotates to turn the windings to produce self-supporting coils or coils in unusual or difficult configurations. In some winding applications, the use of bondable magnet wire can provide advantages over conventional magnet wire by eliminating the need for bobbins and winding or varnishing steps. Activation of the bonding layer can be achieved by heat or, in some cases, by solvent or a combination of both.
Solvent bonding
Some bonding layers can be activated by the use of certain solvents during or after the coil winding process. The application of solvents, usually through saturated wicks during the winding process, causes the bonding layer to reflow. The process requires the use of a device to hold the coil in place while the solvent dries. After drying, the coils should be heated to dry out any residual solvent that may cause long-term coil failure and to complete the bonding process.
Heat sealing
All connection layers can be heat bonded by heating them in an oven or by blowing hot air directly onto the wire during the winding process. In both cases, the principle is to heat the winding to a temperature slightly above the reflow temperature of the bonding layer and then to cool it down to below its nominal bonding resistance temperature. Furnace bonding is achieved by heating the coil for a period of time sufficient to achieve uniform heating of the entire winding, followed by a cooling cycle. The heating time is typically 10 to 30 minutes, depending on the winding size. The disadvantages of oven bonding are the long bonding time and the fact that many winding devices may be required. Hot air bonding, although usually performed at a slower winding speed, has the advantage of eliminating secondary bonding operations. This method is cost effective and is usually associated with low temperature bonding layers and wire sizes up to 34 gauge.
Resistance Bonding
Resistance bonding is performed by applying a current to the winding to electrically heat it to the proper bonding temperature. Tension and bonding time depend on wire size and coil design, and therefore need to be developed experimentally for each specific application. This method has the advantage of being fast and producing a uniformly distributed heat. It is typically used for wire sizes larger than 34 gauge.
