# Application-Oriented Data Analytics in Large-Scale Metal Sheet Bending
## 2 Use Case  
The manufacturing of pipe components requires forming processes that are critical to ensure product quality. One of these processes is the bending of sheet metal using a three-roller machine. This process is carried out to produce pipes with the appropriate curvature tolerances to meet design requirements. However, the trial-and-error bending process can be costly due to material loss and production time. To address this problem, a production method with the minimum number of passes is proposed, ensuring repeatability, precision, and process productivity. To achieve this, a real-time monitoring system is needed to adjust process parameters and achieve the desired shape of the sheet metal. Additionally, the application of artificial intelligence can enhance the monitoring and optimization of the sheet-metal-forming process, similar to that in [15]. The reference flange is shown in Figure 1, along with the bending process, the three rollers involved, and the dimensions of the studied sheet metal. This process is performed using a three-roller bending machine and involves multiple bending sequences in an iterative process. It starts by inserting the end of the sheet metal into the bending machine with the help of a crane, ensuring it is centered with respect to the rollers. Then, pressure is applied with the upper roller on the sheet metal, which is supported by the two lower rollers to prevent the sheet from slipping. This operation is repeated until the curvature meets the tolerance requirements, verified by the worker using a template. In this study, a real-time monitoring system is proposed that uses only the sensors installed on the machine in its current configuration to capture sheet-metal-forming data during the forming process. This process essentially consists of a sheet metal, an upper roller, and two lower rollers (front and rear). The position of the rollers is fixed, as shown in Figure 1. The roller diameters are different (916, 964, and 992 mm), and the length of the lower rollers is L = 4167 mm, while the upper roller has a length of L = 4610 mm. The maximum distance between the upper roller and the lower rollers is 100 mm and will be adjusted based on the thickness of the sheet metal. During the operation, the sheet metal is fed into the rollers. It is then bent to a curvature by adjusting the position of the rear roller, while the front roller rotates to advance the sheet metal and continue forming the desired curvature. However, the upper and front rollers do not exert bending pressure; they are used as support for the sheet metal and simply rotate to allow the sheet metal to pass through them. They do not apply pressure. The success of the three-roller bending process largely depends on the experience and skill of the operator. Typically, the curvature of the sheet metal is achieved through a multi-pass method, also known as \"trial and error,\" to optimize the bending capacity of the bending rollers. However, the multi-pass method entails high costs due to material waste and production time loss. Repeatability, precision, and productivity of the process require the use of a minimum-pass production method. However, the latter method has always been challenging because the operator needs knowledge of the different machine parameters to obtain the pipe component with the desired diameter. The selection of roller diameters and lengths aimed to mirror the standard configuration of the sheet-metal-forming machine employed in this study. Additionally, the chosen diameter, length, and thickness of the sheets align with the specifications of an actual gas storage tank, illustrated in Figure 1. These dimensions were deliberately chosen to capture a realistic scenario within the sheet-metal-forming process. In the central cylindrical part of the tank, there are sheets of two different thicknesses with the same diameter. The conducted tests involved pipes with a diameter of 3050 mm, a length of 17,000 mm, and a thickness of 32 mm (4 sheets) or 44 mm (3 sheets).