Munich, Germany—Humor is not generally an attribute of Swiss businesses, but by naming its new high-speed, single-pulse welding process SHADOW, Lasag AG (Thun, Switzerland), managed to use a light-hearted acronym to get the attention of attendees at LASER 2003. Resulting from a joint development project with Fraunhofer ILT (Aachen, Germany), SHADOW stands for Stepless High-speed Accurate and Discrete One-pulse Welding.
It's a difficult technology to conceptualize and explain in words. Like they say, you have to see it. At the show Lasag used a 50ms, 1.5kW pulse from its new FLS 542C solid-state laser, combined with a high-speed galvo scanner to join a 7mm diameter post to a disc, essentially producing a circular seam weld of 21 mm length in 50 ms with a uniform intensity and weld penetration of 0.3 mm.
The seam surface is smooth without the ripple normally associated with overlap pulsed spot welding, as seen in the accompanying photo.
Classical pulsed laser overlap seam weld (300 mm/min, 25 Hz and 25 J) versus SHADOW with a single 9J, 20ms pulse at 3 m/min.
SHADOW requires half the total energy necessary with conventional seam welding; yet the weld strength is similar or better, and the application window is less critical because of lower thermal considerations. This latter point is of interest in welding of dissimilar materials.
A Lasag engineer told us that weld lengths to 75 mm are possible. This is where the concept begs for an animation explanation. Picture a spinning beam of single pulse (milliseconds long) energy producing a hermetic seal in an implantable device, at a fraction of the normal rate. It's an exciting premise and one that readers in the microprocessing sector should check out by accessing Lasag's website, www.lasag.com.