A flat sheet of material is not actually produced by a mill as a flat sheet. In reality, a flat sheet of material starts its life as part of a coil of material. A Cutting to Length Line / Steel coil auto cutting line will uncoil the material, level it, and then cut it to the required length and stack it. The end product produced by a Cutting to Length Line / Steel coil auto cutting line is a flat sheet of material cut to a very precise length tolerance.