Laser hardening applications

The more important metallic coating methods such as electroplating, spraying, hot-dipping and diffusion have already been considered. There are, however, several other methods which have certain advantageous features and therefore find exclusive application in specific fields. These include new techniques such as laser hardening and alloying. ... 

Laser heating, case hardening by, 16 200 Laser heterodyne radiometry, 23 142 Laser-induced breakdown spectroscopy (LIBS), archaeological materials, 5 743 Laser-induced EDC cracking, 25 646 Laser-induced fluorescence, 23 127 Laser-induced fluorescence imaging, application in combinatorial chemistry, 7 404... 

Determination of the temperature distribution induced by laser, electron, or plasma beam sources is relevant in operations such as surface transformation hardening of metals, drilling, cutting, annealing, shaping, and micromachining. Descriptions of beam-generating devices as well as discussions of applications are available [7-15]. 

Studies in medical applications at Vanderbilt University are leading to the first use of an free-electron laser in human neurosurgery by taking advantage of particular absorption bands to produce an exceptionally fine cut in bone and tissue. FELl has also ablated and hardened dental materials and studied photodynamic therapy. The timabil-ity, power, and pulse variabihty of the FEL has made it an efficient biophysical research tool. 

Examples of the basic chemistry involved in such polymerizations is shown in Fig. 2. In conventional SLA tools, the laser heam diameter is typically on the order of 100 p, in size and the focused heam has a large depth of focus such that a relatively consistent heam diameter can he maintained as the heam is scanned across large areas of the vat. After the first layer of the object is polymerized, the elevator is lowered down by some small incremental distance into the vat, the liquid resin is allowed to flow over the top of the first layer, and the laser is scanned over the surface to initiate polymerization of the second layer of the part in this new resin layer. This process is repeated over-and-over for each layer of the part until the object is completed. Once the object has been made, the part is raised from the resin vat on the elevator, drained and washed of the unreacted photocurable resin, and subjected to various treatments to finish hardening the object. The first commercially available SLA system was produced by 3D Systems in 1987 and SL is now a widely used technique in industries such as automotive and aerospace. In these industries, SL was originally used to fabricate an array of objects from basic design verification parts to show and tell objects at low cost before significant more expense was invested to mass produce or make any actual application-ready mechani-... 

Other laser applications include marking (e.g. product codes), drilling (e.g. where extremely small holes are required) and surface treatment (e.g. annealing, hardening, spraying, coating and cleaning). 

---