& nbsp; In strip processing equipment, the uncoiler is the main equipment for the preparation process, providing post tension during strip operation, supporting the strip, and cooperating with the straightener to feed the strip into the leveler. With the requirements for unwinding speed and surface quality, the types of uncoiler have gradually transitioned from box type uncoiler, non expansion and contraction drum uncoiler, etc. to expansion and contraction drum type uncoiler. This type of uncoiler supports the inner diameter of the coil through the expansion and contraction of the bow shaped plate on the drum shaft, avoiding the disadvantages of edge damage and inner hole slippage of the strip. According to the structure, there are roughly the following types of expansion and contraction drum unwinding machines: single drum cantilever; Double drum rotary type; Double column head unwinding machine with single drum cantilever. Single roll cantilever is suitable for coils with a width of 350mm or more and a thickness of large strips. Most of them are equipped with clutch drive devices and can be passively or actively unrolled. Most of them are equipped with dismantling straight head machines, which are convenient for unwinding; For coils with a width of over 350mm and a large thickness, we recommend using a single drum cantilever unwinding machine. Most of these uncoiler machines are equipped with clutch drive devices, which can be used for passive or active uncoiling, and have forward and reverse drive functions. At the same time, most of them are equipped with dismantling straight head machines for easy uncoiling. The double drum rotary type is suitable for tapes with a thickness of less than 3mm. The double station unwinding machine allows one drum to work while the other can be wound up using a cantilever crane or other methods. After the previous roll of strip is used up, another roll that has already been wound up can be immediately transferred to the strip preparation line for unwinding. This can reduce the winding time and decrease the storage capacity of the tape for subsequent loops. For narrow strips with a thickness less than 3mm, it is best to use a double drum rotary type.  & nbsp; When one roll of the dual roll rotary dual station unwinding machine is working, the other roll can be used in conjunction with a simple cantilever electric hoist or other methods to unwind. After the current roll of strip is used up, the other roll that has already been unwind can immediately rotate to the strip preparation line for unwinding. This can reduce the time required for coiling work and decrease the storage capacity of the tape for subsequent loops. The double column head unwinding machine is suitable for coils with large width and heavy weight. It is equipped with a clutch drive device and can passively or actively unwind. It has the advantages of good strength and rigidity, easy winding operation, stable and reliable operation, good centering, and simple structure. For coils with large width and heavy weight, we recommend using a double cone or double column head unwinding machine. These types of unwinding machines are equipped with clutch drive devices, which can be used for passive or active unwinding. It has the functions of forward and reverse driving, and has the advantages of good strength and rigidity, convenient winding operation, strict, stable and reliable work, good centering, and simple structure. In order to avoid the tipping of coils with larger outer diameters (over Φ 1600mm) during high-speed operation, single drum cantilever and double drum rotary unwinding machines for large coils are equipped with side guide roller devices. All three types of uncoiler are equipped with brakes, which can switch between strong, weak, and release modes. It can prevent accidents caused by excessive rotation of the strip during acceleration and deceleration operation, and also adjust the tension of the strip.