Hot stamping dies require channels for coolants, so that the annealing sheet metal can be rapidly brought to a temperature below 200 °C. The channels were usually drilled straight into the die, meaning that maintaining a location close to the surface was not possible, especially with complex forms. The use of 3D printing allows for the production of dies with channels that follow the surface.
Says Udo Binder, head of the intelligent tooling solutions division at Schuler: “The optimised cooling channel geometry makes the cooling of the die more homogenous and efficient. 3D printing opens up new possibilities in the design of the cooling channels, so that they contribute to even cooling.”
The base material employed in 3D printing is the same steel as Schuler uses in conventional hot stamping dies – albeit in the form of powder that is applied layer by layer and joined by laser welding. The result is a die segment that equals 95% of the mechanical-technical properties of a machined-from-solid die.
Having determined ideal process parameters and optimum powder composition and undertaken extensive tests for tensile strength and specific density, the dies are currently being tested for wear and series production. “The construction of hot stamping dies is practically predestined to be a new area of application for 3D printing; we're ready for it,” concludes Binder.
In January this year, Schuler opened its new hot stamping research and demonstration centre at its home base in Göppingen, Germany. The so-called Hot Stamping TechCenter will be used to demonstrate innovative lightweight vehicle construction applications to customers. Schuler has invested some €6.5 million in the press line located there, which is equipped with a hydraulic press, roller-hearth furnace and automation. It was developed at the company’s Waghäusel, Germany, site.
