Diamond Micro Chiseling of large-scale retroreflective arrays

Triple mirror retroreflectors are essential components for safety applications, communications and measurement equipment. While downscaling of characteristic dimension is possible for triangular retroreflectors, this is a challenging task for full-cube retroreflectors, due to the absence of continuous tool paths. Thus, the Diamond Micro Chiseling (DMC) process has been developed which allows the machining of full-cube retroreflectors by overlapping a series of sharp-edged pyramidal microcavities. In the past, this has been successfully demonstrated on a small-scale up to 3 mm × 3 mm with a structure size of 150 μm. Industrial applications, however, require the structuring of areas which are significantly larger than 10 mm × 10 mm.This paper will introduce the technology for machining such pattern with the help of the DMC process. Particular attention will be given to the measurement procedures and required tolerances for performing an in situ tool change as well as the optimization strategies for reducing the required process time.

► Diamond Micro Chiseling was developed to machine miniaturized cube corner arrays.
► 10 mm × 10 mm arrays with 200 μm and 150 μm structures were machined successfully.
► Novel tool setting procedures allow <0.01° angular and <1 μm lateral accuracy.
► Nickel silver N37 has been identified as suitable for machining large-scale arrays.
► Total machining time was reduced up to 90% by optimizing the cutting kinematics.