Plate shears are important equipment on the uncoiling line. The number of shearing strokes of plate shears determines the productivity of the uncoiling line to a large extent. Generally speaking, the plate shears in the uncoiling line are different from ordinary plate shears, because the uncoiling line has the following special requirements for the plate shears.
(1) High productivity. For the uncoiling line with a plate thickness of 3mm, it is required to cut 30~35 sheets per minute for the plate with a fixed length of 2000mm, and 80 sheets per minute for the plate with a fixed length of less than 500mm. Such a high productivity can not be achieved by universal plate shears.
(2) Full load. Many users of the uncoiling line work in 2-3 shifts, and the plate shears cut 10000 to 20000 times a day. General purpose plate shears cannot be used with such load.
(3) High reliability. If the plate shears in the uncoiling line stop, the whole uncoiling line will stop working. For users like automobile factories, the shutdown of one uncoiling line will also cause the shutdown of several stamping lines. Therefore, it is required that the failure rate of the plate shears in the uncoiler line should be as low as possible, so that the failure diagnosis and troubleshooting are relatively easy.
(4) Variety of coiled material. The universal plate shears use ordinary carbon steel to determine the shearing force, while the coil materials include high-strength stainless steel plates, weather resistant steel plates, acid pickling plates, etc. in addition to the galvanized steel plates, tinplate, color coated plates, and aluminum plates with low strength. Coils used in car production include uncoated cold rolled sheet, hot rolled pickled sheet, high-strength cold rolled sheet, high-strength galvanized sheet, single and double electrolyte coated sheet, single and double hot-dip galvanized sheet, aluminum sheet, etc. Users of the uncoiling line often cannot provide the mechanical properties of the processed materials. Therefore, when designing and selecting the plate shears, the application scope of the machine must be considered.
(5) Special cutting mode. Some uncoiling lines require that the burr direction of the sheared plate should be upward in order not to scratch the surface of the plate due to the burr when stacking the plate. Therefore, the knife rest of the plate shearer should shear from bottom to top. This type of plate shearer is called the downward cutting plate shearer. The sheared sheet falls on the moving conveyor belt. In order to avoid skew, the blade on the tool holder is required to be herringbone shaped, which is especially necessary for the sheet with short length.
