Suman Das with the LAMP System CPT6060, which can be used to build highly complex and demanding ceramic cores and molds. Photo: Rob Felt
A THOUSANDS-OF-YEARS-OLD PROCESS GETS A DIGITAL REBOOT
The stainless steel and glass encasement stands 8 feet tall and at least as wide. Inside, an optical projection system moves in a serpentine pattern across a platform, shooting rays of ultraviolet light into a slurry of photosensitive binder resin and ceramic particles. Dozens of pieces begin to take shape as the projection system makes thousands of passes over the platform.
The machine, which owes its origins to prototypes built by a team of researchers led by Suman Das, a professor in Georgia Tech’s George W. Woodruff School of Mechanical Engineering, is different from 3-D printers that have come before. This one can be used to build highly complex and demanding ceramic cores and molds. It’s called the LAMP™ System CPT6060, produced and marketed by Atlanta-based DDM Systems under an exclusive license from Georgia Tech.
The cores and molds are used for investment casting, also known as “lost wax” casting. Traditionally, making the cores and molds has required a time-consuming process that involves injection molding a ceramic core, creating a wax model around the core, using a ceramic slurry to slowly build a shell around the wax, and coating the shell with stucco to thicken it. After melting out the wax and firing the shell, molten metal is poured into the ceramic mold to form a part.
The LAMP system circumvents that process by fabricating the mold and core in one step from a digital design. In addition to the faster turnaround time, the new technique can reduce the cost of manufacture by as much as 65 percent for new component designs.
The LAMP system works by converting a digital design into thousands of high-resolution images that the machine uses to build parts a single 100-micron layer at a time using a slurry mixture. The 3-D printer is large enough to build numerous parts simultaneously during one session. Once the resin is removed from the molds, they are ready to be fired in a furnace and then directly used in casting.
While the first industrial application of the system is for printing ceramic cores and molds for casting aircraft turbine engine components, the LAMP system is also in great demand for making precision cast components that are used in a diverse group of industries, including defense, energy, biomedical, and automotive.
Aside from printing ceramic cores and molds for investment casting, the LAMP system is also capable of printing a variety of other complex pieces from the ceramic slurry. — Josh Brown
Click image to enlarge. Photos courtesy DDM Systems