A Process for Thinning and Polishing Highly Warped Die to High Surface Quality And Consistent Thickness: Part I

This article, the first in a two-part series, discusses the challenges of thinning highly warped die and explains how they can be overcome with contour machining driven by thickness measurements. The machine that was used measures die surface profiles in situ, producing a wire frame model by which it controls the rotation and movement of the tooling spindle. The thinning process used in this demonstration consists of a grinding step followed by several rounds of lapping, resulting in a uniform die thickness with minimal surface imperfections. The mechanical limitations of flattening a curved die in preparation for die thinning will be discussed in Part II of this article in the November 2015 issue of EDFA.