Accuracy control of three-dimensional Nd : YAG laser shaping by ablation

Improving the dimensional accuracy along the optical axis without decreasin g the materials removing rate is a key issue in three-dimensional laser sha ping. This paper presents a concept for performing three-dimensional laser shaping by directly using machining laser as the photo source of the non-co ntacting measuring device. Due to the high power measuring photo sourer and a 1.06 mu m bandpass filter. the interference caused by the emission light of ablated surface can be effectively avoided, the delay time is not neede d to be inserted between the laser pulse and the measurement. So the measur ement will not decrease the material removal rate and productivity. By usin g this system, the shaping accuracy of 30 mu m can be achieved at the remov ing rate of about 4.0 x 10(-2) mm(3)/sec for Si3N4 ceramic, both are much b etter than the results obtained before. (C) 2000 Elsevier Science Ltd. All rights reserved.