In normal operation of the enamelling machine, the operator's energy and physical strength are mostly consumed in the despooling part, the operator to pay a lot of labor in the exchange of despooling spools, and it is easily to cause quality and operational problems when proceed. The effective method is high-capacity despooling.
The key of despooling is to control the tension, it is not only about the conductor such as thiner and loss of light on wire surface when increase the tension, but also affect a number of performance of enameled wire. When we look at the appearance, there are less shiny when painted the thinned wire. From the performance point of view, its elongation, resilience, flexibility, thermal shock are affected. But if the tension is too small, the wire will easily move even touch furnace mouth. Tension should be uniform, appropriate.
Installing the booster wheel in front of the annealing furnace can greatly help to control the tension. The maximum non-extension tension of the soft copper wire at room temperature is about 15 kg / mm2, the maximum non-extension tension at 400 ° C is about 7 kg / mm2, the maximum non-extension tension at 460 ° C is 4 kg / mm2, and the maximum at 500 ° C Extension tension of 2kg / mm2. In the normal enameled wire coating process, the tension of enameled wire is significantly less than the non-extension tension, requiring control at about 50%, despooling tension control is only about 20% for the non-extension tension.
Large-size high-capacity spool generally use radial rotary despooling device; medium-sized wires use brush-type despooling device; ultra fine wire generally use brush-type or double-cone type of despooling device.
No matter what kind of despooling method, there are strict requirements for both the structure and quality of bare copper wire spools
---- Surface should be smooth to ensure that the wire is not scratched
---- There is 2-4mm radius of the r-angle in both sides of the spool core to ensure balanced release in despooling process
---- After the spool is finished, it must be proceed actuated, static balance test
---- Brush-type device requires spools core diameter: side panel diameter must less than 1: 1.7 or bare wires will appear broken when reached to the core .