Oct 20, 2015 Off Comments in Laser Cutting by

It has always been EWI’s mission to advance manufacturing technologies, particularly in materials joining. This advancement requires identification of emerging opportunities as well as challenges. In laser welding, the opportunities and challenges have increased rapidly and simultaneously since the introduction of higher power fiber and disk lasers. Most notably, higher laser power and beam quality have expanded the opportunities for application to deeper penetration laser welding while introducing a significant new challenge for laser focusing optics.
The specific focusing optics challenge/obstacle is called “focal shift,” and the description of this behavior was published a decade ago by Dirk Lange [1]. In that research, a focal shift was identified and quantified (1mm/kW) at YAG power levels as low as 3kW. Coincidentally, during that same period, EWI was observing similar behavior at 4kW of fiber laser power in an application involving a beam coupler. But the real impact of focal shift in laser welding was observed when EWI began welding trials at 10kW of fiber laser power.

Read more: Cleveland Ohio Laser Cutting: Overcoming focal shift in high-power laser welding