Direct Part Marking of Inconel 718

摘要

Marking of products is necessary in many industries. In order to attain a successful mark, two elements are necessary: a quick, cheap, easy process to produce the mark and an automatic identification of the mark itself by a scanner. The laser marking of metals is one of the most frequently adopted of all laser-material processing techniques. The aim of this paper has been to establish the relationship between the process parameters used in laser marking of Inconel 718 and the characteristics of the mark, both the geometrical- (burr height, mark depth and width) and the optical ones. Michelson contrast and Weber contrast have been used in this paper to qualify the readability of the marks. This choice is due to the fact that this solution is closer to the real use of a mark, which is usually read in daylight and by means of a smart phone in various industrial sectors. An extended experimental plan has been performed and the relationship between the laser mark geometry and the grey tone pixel distribution of the mark image has been evaluated. The experimental results show that the Weber contrast, in spite of some limits, is closely related to the mark shape. The mark readability, as expressed by the Weber contrast, proves to be directly related to the power of the impulse.