Waterjet-assisted Laser Scanning Machining of Large Depth Microgrooves and Microholes with High Efficiency

To address the issues of recast layer and heat affected zone (HAZ) in laser processing in the air, a new waterjet-assisted laser scanning machining (WALSM) was adopted. Laser processing experiments were conducted on DD6 single crystal (SC) superalloy plate to study the effects of various parameters on the microgroove and microhole machining quality, efficiency and taper angle. Results show that WALSM process can eliminate the recast layer, decrease the taper angle, and reduce the HAZ thickness with no microcracks. Orthogonal analysis shows that the waterjet velocity and pulse frequency are the most significant factors affecting the efficiency of WALSM. To further improve the machining efficiency of WALSM in a larger depth, a hybrid laser processing and WALSM process were proposed for drilling large depth holes with high machining efficiency, high accuracy and good surface quality. The hybrid machining process holds great potential in drilling shaped cooling holes on the turbine blades in the aviation industry.