3D-printed extrusion dies: a versatile approach to optical material processing

We report for the first time use of 3D-printed metal extrusion dies for the extrusion of an optical material into an extrudate at elevated temperatures. Using lead-silicate glass as the material to be extruded, the 3D-printed dies demonstrated the same glass flow behavior as conventionally machined metal dies. Evaluation of the extrusion force at set temperature and extrusion speed revealed that the metal-type of the dies used did not affect the glass flow behavior. Using 3D-printed dies as delivered, the high surface roughness of the 3D-printed dies resulted in high preform surface roughness. However, this effect was overcome by finishing the easily accessible internal die surfaces over 1-2mm length upstream from the die exit. The opportunity of using 3D-printed dies offers unprecedented flexibility in the die design for unlimited tailoring of fluid flow within the die, which paves the way towards extruded items of arbitrary shape. (C) 2014 Optical Society of America