Control of blankholder force with electromagnet in sheet metal forming

Nowadays, sheet metal forming process is used in almost every area especially in the automotive industry. The defects such as wrinkles, fractures and springback are common failures that usually occur on the sheets during sheet metal forming process. Such failures are caused by the use of an unwanted and uncontrolled flow rate of the sheet material. The control mechanism such as blankholder force and drawbead of the sheet to minimize or prevent defects that occur on sheet during a sheet metal forming process are used.In this study, using electromagnet to obtain expected sensitive changes during forming in addition to mentioned control mechanism have been planned. For this purpose, a experimental setup built and using the experimental data, a mathematical model to investigate magnetic force obtained as response to changes in voltage in the electromagnet has been developed. Comparison of the results of mathematical model with the corresponding experimental results has been showed in excellent agreement.Furthermore, model predictive controller regulated voltage to obtain reference of electromagnetic restraining force was developed. Model predictive controller was run with given different references and obtained process response closed to reference in a stable manner.