Laser Welding

Sweet spot resonator^®– patented laser technology

Many challenging applications in the jewelry industry require perfect and constant beam quality of the laser beam. The reason for this is that highly reflective materials like silver, gold or copper have a comparably small processing window and show significant deviation in welding quality, if the power density of the laser varies too much.

Conventional laser resonators suffer from “thermal lensing” of the laser rod, i.e. during a pulse sequence the laser rod is heated up and generates a thermal profile which effects the laser beam like a lens. This results in a widening of the laser focus. As a consequence the power density in this pulse sequence is reduced and the welding depth can change dramatically.

To eliminate these problems ROFIN has developed and patented the sweet spot resonator^®, which simultaneously shows three major characteristics:´

• constant welding quality during pulse sequence
• constant beam quality regardless of the selected laser power
• improved beam quality compared to conventional resonators

Thanks to this perfect and constant beam quality the sweet spot resonator^® is very tolerant to material fluctuations or minor misalignment of z-focus positioning. Many applications like welding of small wires or highly reflective materials can only be achieved by using the sweet spot resonator^®. Therefore the sweet spot resonator^® is the key to sophisticated new jewelry designs.