Laser processing is pretty common in our daily life and many of us are quite familiar with it. You might often hear that the terms nanosecond laser, picosecond laser, femtosecond laser. They all belong to ultrafast laser. But do you know how to differentiate them?
First, let’s figure out what does these “second” mean.
1 nanosecond = 10
-9 second
1 picosecond = 10
-12 second
1 femtosecond = 10
-15 second
Therefore, the major difference among nanosecond laser, picosecond laser and femtosecond laser lies in their time duration.
The meaning of utlrafast laser Long time ago, people tried to use laser to perform micromachining. However, since the traditional laser has long pulse width and low laser intensity, the materials to be processed are easy to melt and keep evaporating. Although laser beam can be focused into very small laser spot, the heat impact to the materials is still quite big, which limits the precision of the processing. Only reducing the heat effect can improve the quality of the processing.
But when ultrafast laser is working on the materials, the processing effect has significant change. As the pulse energy increases dramatically, the high power density is powerful enough to ablate the outer electronics. Since the interaction between the ultrafast laser and the materials is quite short, the ion has already been ablated on the material surface before it conveys the energy to the surrounding materials, so no heat effect will be brought to the surrounding materials. Therefore, ultrafast laser processing is also known as cold processing.
There are a wide variety of applications of ultrafast laser in industrial production. Below we will name a few:
1.Hole drillingIn the circuit board design, people begin to use ceramics foundation to replace the traditional plastic foundation to realize better heat conductivity. In order to connect electronic components, thousands of μm level small holes need to be drilled on the board. Therefore, to keep the foundation stable without being interfered by the heat input during hole drilling has become quite important. And picosecond lase is the ideal tool.
Picosecond laser realizes hole drilling by percussion boring and keeps the uniformity of the hole. In addition to circuit board, picosecond laser is also applicable to perform high quality hole drilling on plastic thin film, semiconductor, metal film and sapphire.
2.Scribing and cuttingA line can be formed by continuous scanning to overlay the laser pulse. This requires a great amount of scanning in order to go deep inside the ceramics until the line has reached 1/6 of the material thickness. Then separate each individual module from the ceramics foundation along with these lines. This kind of separating is called scribing.
Another separating method is pulse laser ablation cutting. It requires ablating the material until the material is completely cut through.
For the above scribing and cutting, picosecond laser and nanosecond laser are the ideal options.
3.Coating removalAnother micromachining application of ultrafast laser is coating removal. This means precisely removing the coating without damaging or slight damaging the foundation materials. The ablation can be lines of several micrometer wide or large scale of several square centimeters. Since the width of the coating is much smaller than the width of the ablation, the heat will not transfer to the side. This makes nanosecond laser very appropriate.
Ultrafast laser has great potential and promising future. It features no post-processing required, ease of integration, high processing efficiency, low material consumption, low environmental pollution. It has been widely used in automobile, electronics, appliance, machinery manufacturing, etc.. To keep ultrafast laser running precisely in the long term, its temperature must be well maintained. S&A Teyu CWUP series portable water chillers are very ideal for cooling ultrafast lasers up to 30W. These laser chiller units feature extremely high level of precision of ±0.1℃ and support Modbus 485 communication function. With properly designed pipeline, the chance of generating bubble has become very slim, which lowers the impact to the ultrafast laser.
