Case study of mass customization of double-curved metal façade panels using a new hybrid sheet metal processing technique

Despite general perceptions, mass customization of double-curved metal panels with slight variations remains challenging. This paper reports the results of a three-year effort to develop a new hybrid sheet metal processing technique to fabricate double-curved metal panels for the Dongdaemun Design Park (DDP) building. DDP, designed by Zaha Hadid, has an unusually high percentage of double-curved panels. Among the 45,000 façade panels, approximately 22,000 panels are double curved. Despite the complexity and the large number of different types of panels, the joints are only 25 mm wide. Precision and a limited budget were the key requirements. The project team successfully developed a new and affordable sheet metal forming method called multipoint stretch forming, which is a hybrid method of multipoint forming and stretch bending, through trial and error. Several machines and prototypes were custom built and tested. The cost of fabrication of typical double-curved panels using this new method was US$260 per square meter compared with US$7,000 per square meter when die casting was used and US$3,000 per square meter when hydroforming was used. Furthermore, the average fabrication time per panel was reduced from several hours to 15 min per panel when using the new multipoint stretch forming method.