A Study on Improving the Shape Error of the Lower Mold of Free-Form Concrete Panels Using Magnetic Force

FCPs (free-form concrete panels) can be made using reusable and easily customizable silicone molds tailored to the unique shape of each panel. CNC (Computer Numerical Control)-type rods move vertically to press the silicone plate and shape the lower curved surface. Silicone caps are attached to the ends of the rods to facilitate the formation of smooth curves. However, there is currently no fixing method for the silicone caps and the silicone plate, which makes them vulnerable to the lateral pressure exerted during concrete pouring. Therefore, the current study used magnetic force to improve the lower shape of free-form molds. To this end, a neodymium silicone cap was designed by adding a neodymium magnet to the upper surface of the silicone cap. Moreover, two types of silicone plates were developed for fixing: one type is IS-LSM (Iron Sheet–Silicone Mold), which includes an iron sheet, while the other type is IP-LSM (Iron Powder–Silicone Mold), which is made by mixing iron powder. To verify these two techniques, FCP manufacturing experiments were conducted. The experimental results indicated that IS-LSM had a broader error range than existing techniques, thus rendering it unusable, while IP-LSM yielded significant values. Consequently, a t-test was conducted to validate the data for IP-LSM at 30%, 50%, and 70%, and it was confirmed that the difference in error data was significant at a 95% confidence level. Future research in this area should investigate the addition of iron powder to the silicone plate and a side fixing method for the silicone mold. Such research would help advance the production technology of free-form concrete panels.