Improving Global Quality of Life

Portable power: In the Portable Power market, growth is being driven by high-drain wireless
consumer devices. Primary portable power applications include consumer products, industrial and
professional products, personal communication devices, portable computers, and military portable
electronic devices. Rechargeable batteries and small engines will lead gains among established
technologies. Solar cells are projected to remain niche items, while miniature and micro fuel cells
become a major factor within this market by 2013. In the area of fuel cells, portable electric power
is viewed as one of the earliest market applications. Much of the complexities related to hydrogen
infrastructure are not an issue for portable electrical power applications, as is the case with many
other fuel cell applications.
9.15 Microjoining sector
Pressure sensor incorporating,
laser, electron beam and
thermosonic welding
The involvement of microjoining in the electronics, instrument,
actuator and sensors industries is as important and as extensive as that
of welding in other manufacturing industries. The proper functioning
of small mechanical devices and electronics systems, as employed in
the aerospace, medical, telecommunications, computer, automotive,
oil & gas and consumer industries, is critically dependent upon the use
of efficient and reliable joining techniques. The increasing complexity
and miniaturisation of micro and miniature devices are placing more
stringent demands on assembly techniques for, and the performance
of, microjoints.
The full range of welding, soldering and adhesive bonding techniques is being
pushed to the limits to cope with increasing miniaturisation, process speeds
and rapid changes in design. Additionally, the global drive to environmentally
acceptable products is resulting in a review of assembly and disassembly
techniques which is forcing a rethink in terms of the use of materials, joining and
assembly processes. Although the term microjoining is widely used, it is difficult
to define exactly. For the purpose of this review it is taken to include the joining
of sheet and rod materials up to 1 mm in joint thickness.
Ball/wedge wire bonded
die assembly
Ultrasonic
welded electrical
terminations
Micro friction stir
welded 0.5 mm thick
Aluminium sheet
Welding is extensively used in microjoining applications such
as silicon chip interconnect (e.g. wire bonding- thermosonic
welding), package sealing (e.g. laser and resistance welding)
and sensor/mechanical system assembly (e.g. EB, arc and
resistance welding). There is the potential however to
increase its use by exploiting its capabilities in terms of local/
low heat input, rapid processing capabilities and enabling
more environmental assembly/design as illustrated.
142 Improving Global Quality of Life Through Optimum Use and Innovation of Welding and Joining Technologies