Scissor line

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A scissors line is the arrangement of various scissors for trimming sheet metal along a transport device , usually a roller table .

Internationally she is awarded the Engl. called shearing line . The manufacturer market is dominated by the German-speaking area and Japan, but the operators of the systems are spread all over the world. The English names that are often used are therefore also given here.

Cutting of thin sheets

The trimming of sheet metal is usually done immediately before further processing in the relevant company. Most of the cold strip is a coil having 10 to 30 tons of material from an unwinding reel (engl. Pay off reel ) performed in the shear line, where, depending on the further use and non- rectangular and odd cuts are made. In order to smooth the sheet metal unwound from the coil, straightening machines are usually connected upstream. One of the most common applications is the cutting of sheet metal for body shell construction in the automotive industry .

Cutting of heavy plates

Larger heavy plates in particular are trimmed on the rolling mill. You can find e.g. B. in the construction of bridges, drilling platforms or pipelines use. The individual scissors in such a line are each the size and weight of a single-family house and have a significantly higher electrical connection load, which makes on-site operation uneconomical, if not impossible. In addition, one tries to keep the transport weight of the individual sheets as low as possible, since the transport costs multiply with weights over 30 tons. Only straight and right-angled cuts are made on heavy plate with scissors; torches are usually used for other cuts. According to direction and purpose, a distinction is made in the order of the usual arrangement:

  • Cropping shears (engl. Crop shear ) for severing the tuft , inferior parts of the head and foot of the sheet
  • Trimming shears (engl. Trimming shear ) for separating the seam , inferior parts on the sides of the sheet; Usually a pair of scissors is used for the right and left side of the sheet
  • Slitting shear (engl. Slitting shear ) for splitting in the longitudinal direction
  • -Length shear (engl. Dividing shear or crosscutting shear ) for dividing in the transverse direction

In smaller systems with a lower throughput, sometimes only cropping and trimming shears are used. The slabs are then rolled out from the outset into sheets of appropriate dimensions. With varying dimensions, however, this leads to a poorer utilization of the roll stand and thus the overall system.

Flying scissors line

In so-called flying scissors lines or flying scissors, the strip or sheet is not stopped during the cuts. Longitudinal cuts must be precisely synchronized to the speed of the strip or sheet metal; for cross-cuts, the appropriate scissors are carried in a frame during the cut. The process is mostly used for thin sheet metal, since a strip is fed in continuously and the throughput can be increased. At the foot of continuous casting plants that are directly connected to the non- continuous processing of individual slabs, a flying cut-to-length shear or a corresponding cutting torch (for larger slab thicknesses that do not allow a clean cut with scissors) must be provided, since the casting process is not without complex renewed casting can be interrupted. This is particularly common in more modern plants in which the slabs are fed into a walking beam furnace immediately after being cut. Here they do not have to be reheated, but the temperature distribution between the surface and the core is simply equalized and adjusted to around 1200 ° C for hot rolling , which results in a significant saving in the energy used.