The increasing complexity of microelectronics/ engineering devices and the requirement for higher yields and automated production systems place stringent demands on the assembly techniques and performance requirements of materials and joining techniques.  This increased interest in the use of lasers for microwelding applications across a range of applications.  The term micro-welding also known as precision welding, refers to welding the parts that have a weld bead size <1mm and a weld penetration depth <1mm. Besides the size of the weld seam and the depth of penetration of the weld, other laser microjoining requirements are:

• Very fine welds (spot sizes can vary approximately. 10um up to 100um);
• Decreased distortion and heat affected area;
• Reliability and stability of the process (pulse-to-pulse stability for spot welding);
• High processing speed (welding using a scanner);
• Welding of reflective materials;
• Welding of dissimilar materials.

Laser microwelding is used for joining high value miniature components in a range of industries i.e., Electronics, Telecommunications, Automotive & Medical Industry (Table 1). Compared to conventional microwelding methods i.e., resistance, flash, arc, TIG, and MIG, plasma laser micro-welding offers several advantages i.e.  

• Low heat input: The weld energy is delivered only to the point where it is needed and with exceptional control;
• Clean welds: In addition to the aesthetic advantages, clean welds provide products that are easier to sterilize or integrate into other joints;
• Strong welds: The laser offers high strength and a minimum number of welds;
• Hermetic welds: In contrast to soldering or brazing, lasers can provide flawless hermetic welds essential for many micro applications.

 Table 1: Examples of microwelding applications

Everfoton offers several low-power SM CW and Quasi-CW optical fiber lasers for micro-welding applications and some examples of micro-welding are highlighted in (Figure 1).