In classic strip processing, the winding and unwinding of the strip play a pivotal role as bundle sizes and winding/unwinding safety significantly influence subsequent processes and production times. The simplest and most commonly used method of winding in the steel strip industry is the winding into Pancakes.
However, this winding method comes with some drawbacks. Since the diameter of the ring is typically structurally limited, only relatively short running lengths can be achieved. This, in turn, translates to a high level of manual effort in subsequent processes, as feed bundles often need to be changed frequently. Additionally, there are added sources of errors, as weld seams are required to connect the pancakes. These seams can lead to problems in subsequent processing and are generally undesirable in the end product. Furthermore, the removal of pancakes is often done manually, as installing elaborate crane systems above the facilities would be necessary otherwise. With workplace ergonomics becoming increasingly important, this further limits the possible ring diameters.
To ensure the competitiveness of the German production site, it is evident that automation will be a central aspect in the coming years. Recognizing this trend decades ago, Cobra has gradually transitioned its production to coiled material.
A comparison is used to clearly illustrate the advantage. For a material width of 13 mm and a thickness of 0.18 mm, a pancake (inner diameter 400 mm, outer diameter 700 mm) can accommodate a running length of approximately 1,400 m (or 26 kg). By using the same inner and outer diameter and winding the material onto a coil with a depth of 180 mm, a running length of about 14,000 m (or 260 kg) is achieved. In this example, the coil runs approximately 10 times longer in the subsequent process, requiring only a single weld seam instead of the 10 needed with pancakes.
The transition to coiled material offers several advantages: The manual effort and probability of errors are significantly reduced due to the longer running lengths. The Easy-Load System developed by Cobra allows coils to be easily lifted using prism pallets and electric pallet trucks. Consequently, processing with coils is more ergonomic, safer, and notably more efficient than processing with pancakes.
With over 20 years of experience in processing coiled material, Cobra has continually improved its winding system. The latest generation of winders (CTW 1500) can accommodate coils with a material capacity of up to 1,500 kg.
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