A die is a specialized tool used in manufacturing industries to cut or shape material mostly using a press . Like molds , dies are generally customized to the item they are used to create. Products made with dies range from simple paper clips to complex pieces used in advanced technology Forming dies were typically made by tool and die makers and put into production after mounting into a press . The die was a metal block that was used for forming materials like sheet metal and plastic . For the vacuum forming of plastic sheet only a single form was used, typically to form transparent plastic containers (called blister packs ) for merchandise. Vacuum forming was considered a simple molding thermoforming process but uses the same principles as die forming. For the forming of sheet metal, such as automobile body parts, two parts may be used: one, called the punch , performed the stretching, bending, and/or blanking operation, while another part that was called the die block securely clamps the workpiece and provided similar stretching, bending, and/or blanking operation. The workpiece may pass through several stages using different tools or operations to obtain the final form. In the case of an automotive component, there was usually be a shearing operation after the main forming was done and then additional crimping or rolling operations to ensure that all sharp edges were hidden and to add rigidity to the panel.