About the process of laser drilling machine

Laser drillingThe technology is very mature today in 2022 and is one of the main application areas of laser processing. The laser drilling machine has been improved many times and is suitable for most materials.

Laser drilling refers to the laser beam producing small or large holes in different materials.

Laser drilling machines are widely used, such as the connection between the inner layer and the inner layer, and the outer layer and the inner layer of the printed circuit board PCB. A high-precision laser is used to penetrate the copper plate and the inner layer resin, and then copper is plated to complete the circuit connection.

For example, processing micrometer holes on hard tungsten carbide and tens of micrometer deep holes on red and sapphire, such processing tasks are difficult to use traditional mechanical processing methods, and sometimes even impossible, but laser punching is not difficult to achieve.

During laser punching, a short pulse laser with high power density transfers huge energy to the workpiece in a short time. This causes the workpiece material to melt and evaporate. The higher the pulse energy, the more material melts and evaporates. During the evaporation process, the volume of the material in the hole expands sharply, generating huge pressure, and the molten workpiece material is introduced from the hole.

The ultra-short pulse laser of the picosecond laser is particularly special. In this process, the workpiece material directly changes from solid to gaseous without melting, that is, sublimation, and the workpiece is not heated.

Over time, several different laser punching processes have been developed based on this basic principle:

Rotary Drilling

Multi-pulse laser beams also create holes when rotary drilling. First, the laser drilling machine uses an impact drilling process to punch the initial hole. The laser then moves in several increasingly larger ring tracks above the workpiece to enlarge the initial hole. In the process, the vast majority of the workpiece material melt is pushed downward from the hole.

Spiral Drilling

Unlike the drilling process, no starting hole is created when spiral drilling. When the laser pulses start firing, the laser moves in a ring track above the workpiece. This causes much of the material to overflow upward. The laser's motion trajectory is like a spiral staircase, gradually extending downward. In this process, the focus can always be guided to the position so that it is always at the bottom of the hole. If the laser has penetrated the workpiece material, the laser must make a few more turns. The aim is to enlarge the bottom of the hole and make the edges smoother. Spiral drilling produces holes of large size, depth and high processing quality.

Single-pulse drilling and impact drilling.

In the simplest case, a single-pulse laser beam with relatively high pulse energy produces the hole. In this way, many holes can be produced very quickly. In the impact process, a multi-pulse laser beam with smaller pulse energy and pulse period is used. The holes produced by the impact process are deeper and more accurate than those produced by a single-pulse hole. In addition, the impact process can make the hole diameter relatively small.