Improving Laser Microcutting Quality of AZ31 Mg Alloy by Submerged Cutting for Manufacturing of Biodegradable Stents

Cardiovascular stents are typically produced by laser microcutting of tubular precursors. The cutting edge quality is a key factor for the correct interaction between the human body and the inserted biomedical device. The reduction or elimination of dross during process is desired for increased productivity in manufacturing. Laser cutting with the aid of submersion liquid can improve the cut edge quality, which can be exploited also in the case of manufacturing of biodegradable stents in Mg alloys. In this work, submersion cutting of AZ31 Mg alloy with a pulsed green fibre laser is demonstrated. Three different submersion liquids, namely pure water, ethanol-water solution and paraffin based lubricant oil were used and compared to dry cutting condition. The impact on quality was quantified by the amount of deposited dross and complete cut penetration. The results show that surface dross can be remarkable reduced by the correct selection of submersion liquid and laser processing parameters.