Introduction To Ultraviolet Laser Processing Application In PCB Industry

For laser cutting or drilling of circuit boards, only a few watts or ten watts of UV laser is needed. No kilowatt-level laser power is required. Flexible circuit boards are becoming increasingly important in consumer electronics, automobile industry or robotics manufacturing technologies. UV laser processing system has become the first choice for flexible PCB and thin PCB laser drilling and cutting due to its flexible processing mode, high precision processing effect and flexible controllable processing process.

FIG1: Comparison of cutting groove between CO2 laser (left) and UV laser (right). UV laser produces small thermal effect, its cutting edge clean, neat

Today, the laser system configuration of the long-life laser source is almost maintenance-free, in the production process, the laser level is 1, safety without other protection devices. LPKF laser system is equipped with vacuuming device, which will not cause the emission of harmful substances. Coupled with its intuitive and easy to operate software control, laser technology is replacing traditional mechanical processes and saving the cost of special tools.

CO2 laser or UV laser?

For example, a CO2 laser system with a wavelength of approximately 10.6 m can be selected for PCB board splitting or cutting. The processing cost is relatively low and the laser power can be several kilowatts. But it produces a lot of heat during the cutting process, resulting in severe edge carbonization.

The wavelength of UV laser is 355 nm. Laser beams of this wavelength are easily focused optically.

A focused UV laser with less than 20 watts of laser power produces a spot of 20 m in diameter — and produces an energy density comparable to the surface of the sun.

Advantages of UV laser processing

UV laser is especially suitable for cutting and marking rigid board, flex board, rigid-flex baord and its accessories. So what are the advantages of this laser process?

UV laser cutting system shows great technical advantages in SMT circuit board and PCB micro-drilling.

Depending on the thickness of the circuit board material, the laser cuts one or more times along the desired contour.

The thinner the material, the faster the cutting.

If the accumulated laser pulse is lower than the required laser pulse to penetrate the material, only scratches will appear on the surface of the material.

Therefore, two-dimensional code or bar code can be marked on the material, so as to track the subsequent process information.

FIG2: Multiple components of a substrate, even close to the circuit, can be safely separated

The pulse energy of UV laser only affects the time of microseconds on the material, and there is no obvious thermal effect at the few micrometers beside the incision, so there is no need to consider the damage caused by the heat generated to the element. The lines and solder joints near the edge are intact and free of burrs.

In addition, LPKF UV laser system integration CAM software can directly import the data derived from CAD, edit the laser cutting path, form the laser cutting contour, select the processing parameter library suitable for different materials, then direct laser processing can be done.

The laser system is suitable for both mass production and sample production.