Industrial Laser Types

There are two main types of industrial laser of interest to structural fabrication; CO ₂ and Nd:YAG lasers. The lasers have different characteristics that are summarized in Table 1.

Table 1. Summary of characteristics of CO₂and Nd:YAG lasers

Property	CO2laser	Nd:YAG laser
Lasing medium	CO 2 +N 2 +He	Neodymium doped yttrium aluminium garnet crystal rod
Radiation wavelength	10.6µm	1.06µm
Excitation method	Electric discharge	Flashlamps
Efficiency	5-10%	2.5-5%
Output powers	Up to 60kW	Up to 4kW
Beam transmission	Polished mirrors	Fibre optic cable

High power CO ₂ lasers are predominantly used for the welding of automotive components, such as gears and transmission components, which require circular and annular welds and in tailored blank applications. The majority of lasers have a power of 6kW or less.

High power Nd:YAG lasers are now available at workpiece powers of 4kW, which have fibre-optic beam delivery. The welding applications are concentrated in body-in-white assembly. Higher power equipment is likely to be developed in the next 2-3 years and there are likely to be improvements in the efficiency of Nd:YAG lasers with the arrival of diode pumped Nd:YAG lasers.

Within the laser industry, one of the main advances in the past two years has been in diode lasers (wavelength 0.8-0.9µm), where 2kW systems are now commercially available. However, at the current status of development, the power densities required for welding of sheet materials used in the automotive industry (about 1x10 ⁶ W/cm ²) have not been achieved. Research work is underway in Germany to develop diode lasers and their applications and this situation may change in the next 3 years.

Nanotechnology in Batteries(Unit 5)

By Will Soutter

Nanotechnology can play a significant role in the achievement of specific performance objectives in batteries. Conventionally, graphite powder has been used as an intercalation material on the negative electrode for lithium ion batteries. The rate of removal or insertion of lithium and the battery capacity can be improved by replacing micrometer-sized powder with carbon nanomaterials such as carbon nanotubes. Since carbon nanotubes have a high surface area, they can bind much higher concentrations of lithium. Nanowires made of titanium dioxide (TiO₂), vanadium oxide (V₂O₅) or tin oxide (SnO) are also promising as negative electrode materials.

Commercial development of many of these materials is still in the early stages - one of the challenges in making fundamental technology changes to a giant industry like the automotive industry is that any new technology has to be ready to adapt to the huge scales of manufacturing involved. Presently available commercial oxide materials are promising candidates for electrode materials, but most of them are expensive or have safety limitations. Li(NiCoAl)O₂, Li (NiMnCo)O₂, LiMn₂O₄, Li(AlMn)₂O₄ or LiCo₂O₄ are good examples of such compounds. The nanostructuring of these materials has been shown to significantly improve their intercalation capacity.

Using nanostructured materials to improve the current density of electrodes for a number of reasons - it reduces the diffusion path for the lithium ions, increasing their mobility, and also tends to increase electrical conductivity, making the electrochemical reaction occur much more efficiently. A variety of nanostructured materials such as nanotubes, nanowires, nanopillars, nanoparticles and mesopores have been examined as candidate materials for both positive and negative electrodes. By varying the properties of the electrodes, like morphology, and surface area, researchers are aiming to find optimum compositions to squeeze as much performance as possible out of batteries which are as affordable and as light and compact as possible.

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(Unit 6)

With this project, ZF is making use of its long-standing know-how of adaptive dampers. ZF is a global leader in driveline and chassis technology with 121 production companies in 26 countries. More than 2.2 million dampers has been produced for the following customers: Alpina, Audi, Bentley, BMW, Ferrari, Maserati,Opel, Rolls-Royce, Mercedes-Benz, Porsche and Volkswagen. The company expects an annual production of more than three million CDC units for passenger car applications alone by 2016. In addition, there are ZF systems for buses, trucks, agricultural machines and motorcycles.

Notes:

Levant Power Corp. is an emerging technology company headquartered in Woburn, Massachusetts working to develop the world's first fully active, regenerative suspension for the automotive, trucking, mass transit, and defense industries. Levant Power was founded in 2009 out of the Massachusetts Institute of Technology.

ZF (ZF Friedrichshafen AG) is a global leader in driveline and chassis technology with 121 production companies in 26 countries. ZF is one of the 10 largest automotive suppliers worldwide.

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