From the 1960s to 1980s, people used various nonlinear crystal materials to carry out intracavity frequency doubling Nd: YAG lasers to obtain green light sources. In the 1990s, all-solid-state green laser with high power and high repetition rate, which has the advantages of long life, high reliability, small size and high efficiency, has achieved unprecedented development. With the improvement of the quality of domestic semiconductor lasers and the reduction of the price of foreign semiconductor lasers, the research of all-solid-state high-power green lasers in China has also made great progress.
In 2021, Germany Tongkuai first launched its 3 kW high-power continuous green disc laser. It is reported that the average output power of this product is up to 3 kW, representing the strongest power in the current green laser series. It is very suitable for the welding of copper, aluminum and other high-reflective materials. Especially in the lithium battery industry represented by the power battery of new energy vehicles, the fast green laser (1000-3000W) can realize the welding of up to 120 layers of copper foil, with almost no spatter and accurate and controllable penetration. In addition, high power green light also has prominent advantages in pure copper material additive manufacturing – 3D printing application.
According to the research results given by the German Institute of Photonics Technology, when copper is in solid state at room temperature of 20 ℃, the absorption rate of green light band is about 40%; When the temperature rises to 1600 ℃ and the copper is in the melting state, the absorption rate decreases by about 5%. That is, the absorption of green light after copper melting is slightly decreased. This feature helps to obtain stable small holes when processing copper, and can achieve almost zero splash. This is the obvious advantage of green laser over infrared laser welding.
The above research proves that green laser can be used as the best light source for 3D printing of high-antimetallic materials. 3D printing of pure copper materials can well solve relevant problems and achieve a density of more than 99.95%. In the future, green laser is expected to be applied to 3D printing of pure copper materials, and the market scale of 3D printing of pure copper materials is also expected to be further expanded.