Cut to Length Line Makes the Best Benefit for Users

Posted on Jan 6, 2020


In the metalworking industry, a cut to length line (or sometimes solutions instead) is abbreviated as C. T. L., or a blanking line. The operation procedure involves a primary coil of flat rolled steel on the wheel from the mill. It unrolls, and get flatten, and then be cut to precise length sections, and eventually people or automation system will stack the sheets into a bundle.

Relevant Equipment of Cut to Length Line

Regarding the relevant equipment of the cut to length line, the units vary according to the sheet width, sheet thickness, and the weight of the incoming coil materials. In addition, the materials, working conditions, and many other variables are also recognized as critical concerns for the CTL solution, but most importantly, all the setting is based on the final end product features which is about to be exploited by the cut sheet. Furthermore, flatness may also be a critical point and be utilized as a double leveler or sometimes stretcher leveler may be used in the process.

How Many Kinds of CTL?

There are mainly four categories in the market, but in Taiwan, there are mostly two kinds so that in this short essay we will only cover a few of them. The trapezoidal cut to length (trapezoidal CTL) line arranges the shear cutting on a specific angle from 90 degree perpendicular angle to the strip to 30 degrees of tangent angle.

Therefore, due to its features, these cut sheets or blank sheets are used primarily in the automotive and taper pole industries as the applications in these two industrial sectors are widely used best known for the great versatility and agile nature.

On the other hand, there is the stop go cut to length solution (tight line mode), which is less costly than the continuous CTL model, but the later one we will not discuss here in the essay. Regarding the stop go CTL, the metal strip is fed through the line rapidly and then be decelerated later, and eventually comes to a full stop.

In this model, the stationary shear fires, and a finished sheet or cut blank is produced to a predestined size of length. The tight-line configurations can be an ideal option once if the footprint inside the plant is limited, since they usually are shorter than free-loop designs compared with other models.

The foundation expense is even lower because a looping pit is not a prerequisite, and the thickness capacity of the tight-line machines is virtually unlimited, which ensures them as perfect model for heavy gauge applications in the industry. Besides, the tight-line machines with stationary shears have the lower prices of any cut-to-length solution line, but at the same time it is with the lowest productivity as well, making it less effective in one considered in this perspective. Therefore, the production model a business owner has is the key when they are considering about the CTL solution line arrangement. What is more, the tight-line machines may even damage thinner materials because visible roll marks may appear where material stops in the leveler.

Critical Components of CTL Solution Lines

As discussed above, the procedure of a cut to length steel coil cutting line integrates a lot of machineries and equipment. Here we would give a picture of what are involved in the line, achieving the perfect flat steel sheets. The critical components of the steel coil cutting to length line solutions includes (but not limited to) coil car, stacker, de-coiler, head straightener (or say, leveler), coarse leveler , loop, vertical roller device, fine leveler, cut shear, delivery conveyor, hydraulic system, electric control system, bolts & buries components, and shear, just to name a few here to include most cases.

The materials of input steel coils vary from time to time. It can be plain, hot rolled steel, rolled cold steel, galvanized steel (GI,GP), colored steel(PPGI), stainless steel, silicon steel, aluminum, copper, etc. Regarding the cut numbers, many CTL suppliers are able to supply cuts number over 40 cuts. In the case, a flying shear can be installed to increase productivity specifically in the case of heavy gauge model.

The ASP flying shear must be synchronized perfectly with the speed and the location of the moving strip since synchronization is very important. However, thought Synchronization can be achieved, but the cost is usually substantial, so that many manufacturers may try to adjust it by themselves rather than buying an automation system that save time but costly which is hard to cover by the product output.

Detail Process of the CTL Flow

Speaking about the detail process of the cut to length line solution, there are coil loading at the very beginning, then is the uncoiling process that releases the rolled metal materials. Later is the strip end straightening for the materials, and then is the coarse leveler, followed by loop procedure, and then is the vertical roller fine leveler. After the above mentioned procedure, is the cut shear procedure in which there are cut shears to be processed, and then is the plate stacker that aims to get the materials in stack and eventually, to be delivered on the delivery cart. The carts vary according to the plant conditions so that the final part is not so strictly confined to a certain conveyor compared to the other part mentioned in this section.

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