A fast method for morphological analysis of laser drilling holes

Abstract

This paper presents an original method for analyzing laser drilled holes. The so-called Direct Observation of Drilled hOle (DODO) method is introduced and its applications. The hole characterization that’s been made is compared with x-ray radiography and cross-section analysis. Direct Observation of Drilled hole provides instantaneously surface state, geometric shape, as well as recast layer structure, without additional operation. Since no mounting resin is used to embed the sample, the preparation for analysis is simplified and, gives access to a 3D analysis of hole morphology. The principle of this technique consists in positioning the drilling axis on the joint plane of a butt configuration. Surfaces of the two parts of the sample to be joined are polished beforehand, to increase the contact surface, and then holes are drilled in the joint plane. Once the sample is drilled, the two parts are split so that one half of the hole is in each part of the sample. The preparation time of DODO method samples is shorter than the polishing time of the classical method. Moreover the implementation of the DODO method is much easier, for quality control as well as process development in laser drilling.