A cut to length (CTL) line—sometimes called a blanking line—starts with a master coil of flat-rolled steel, then unrolls, flattens, and cuts sections to a precisely assigned length. From there, cut pieces are stacked into a bundle for transport or storage. Depending on the type of metal, the process can operate as a continuous free loop (for lighter gauge metal), or as a start-and-stop process (for heavy gauge metal).
Depending on manufacturing needs and the final end product, cut-to-length lines may also include a double leveler, skin pass, or stretcher in the process. The equipment involved will vary depending on factors such as incoming coil weight, width, and thickness of the final product.
With this method of producing CTLs, a strip is fed from a master coil through a flattener and/or leveler at a constant rate according to the desired thickness and speed of cutting to length. A separate feeder measures and guides the material for shearing, which could be either stationary or flying type.
Sometimes referred to as secure line mode, stop-and-go lines are often less expensive than continuous CTLs. In this process, the strip is fed through the line quickly and then brought to a complete stop. A stationary shear is applied, resulting in a sheet or blank of predetermined length.
A stop-and-go process is a popular process for those manufacturing areas where space is limited because they are usually shorter than continuous free loop designs. The thickness capacity of stop-and-go machines is pretty much unlimited and perfect for heavy-gauge jobs. While processing machines with stationary shears cost less than continuous free loop machines, they also have the lowest productivity as well. In some cases, they can also cause damage to lighter gauge materials due to visible roll marks where material stops in the leveler.
Options exist in installing a flying shear to increase production—particularly for heavy gauge material, but the flying shear must be timed and positioned correctly with the speed and location of the moving strip.
For some industries, such as automotive, a trapezoidal CTL is needed. In this process, shear cuts can be made at angles ranging from 90 degrees perpendicular to the strip to a 30-degree slant.
Whether your manufacturing goals are for construction, electronics, cutlery, automotive, or something else, you have different options in CTL lines for your material needs.