另外用YAG打这样的孔，需要多大功率，聚焦镜的焦距是多少，用的什么气体？作者: alanick 时间: 2004-2-11 07:21 标题: 关于激光打孔 CO2好像比较难打这么小的孔，热影响区太大。
YAG的以前听说有个老师用灯泵的可以做0.01的孔，至于能打多深，用什么气体，具体情况就不是太清楚了。作者: zycpet 时间: 2004-2-11 15:08 标题: 关于激光打孔 我现在在英国学激光，研究不敢说。不过我们做过drilling方面的试验。
以下是我试验报告里面的一些内容，希望对你有帮助，如果有错误请指出。
1. Pulse power
The pulse power can be set into many values in different duration of one pulse. For many material the reflectivity of infrared laser are very high, thereby, a high initial peak power is required to melting the surface in order to decrease the reflection. Especially for drilling, the material must be vaporized, hence, the laser intensities are of the order 107 W/mm2.
2. Pulse width
Pulse width is the duration of pulse. The pulse width in laser drilling is much shorter than the thermal conduction of material. Thereby, the temperature can increase to boil point by the accumilation of energy.
3. Pulse shape:
Pulse shape is the shape of one pulse, in other words, in one pulse, there are several different values of power in different periods. In this lab, five forms of pulse shape to be investigated, they are a square pulse, a ramping-up pulse, segmented ramping-up pulse, a ramping down pulse, and a segmented ramping-down pulse.
4. Focal position:
It is the position of the focal point of laser beam. Because the beam of Nd:YAG laser is invisible, a test film should be used to find the focal position. Put a test film on the processing table, change the distant between lens and test film. Drill some hole on the test film and record every distant of the drilling. At last, the distant of the corresponding smallest hole is the focal position. The diagram is shown below.
5. Assist gas:
The gas used in this lab is Oxygen which can enhance the reaction of drilling. The pressure of assist gas should be much higher than in welding, because one of functions of this gas is blowing away the vapour and liquid of material from the drilled hole. In this lab, the pressure is 5bar.