The modern pulsed Nd:YAG laser offers the application of various micro-welding strategies due to pulse forming capability and possible pulse energies of up to 1501. Those welding strategies range from single pulse spot and contour welding to high quality seam welding and differ in the local thermal properties.
Single pulse spot welding with millisecond pulses adapted in their temporal energy delivery to the melting process of metals like Aluminium, Titanium or Copper alloys, allow high quality welds even for dissimilar combinations. It can also be shown that the quality of conventional seam weld benefits from these pulse forming capabilities.
Single shot contour welding can be done with beam shaping optics in combination with pulse control. Depending on the size of the contour the pulse energy is the limiting factor. Pulses up to 1501 have been applied to weld circular shapes with diameter of more than 2mm in stainless steel to study penetration and weld geometry.
A different strategy is the single pulse high speed contour welding (up to meter/s) in combination with fast galvos, rotational optics or mechanical axes. It turns out that this welding leads to different thermal behaviour of the melt pool compared to the single shot welding or slow seam welding. The results show that many difficult similar and dissimilar alloys can be joined efficient and with low heat damage and very good stability.