The Alchemy of Laser Cladding
By Angela Sanders Sunday, January 12, 2014, 05:54 AM EST
Metallurgy, the study of the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures (which are referred to as alloys) might well be said to be the precursor to cladding, the bonding together of dissimilar metals. Earliest known examples of human exploitation of metals date back to Spanish caves circa 40,000 B.C. (the late Paleolithic period) and man continues to seek out new ways to exploit to advantage the utility of metal. The term metallurgy also denotes the technology of metals (how science is applied to the production of metals, and the engineering of metal components for use in products for consumers and manufacturers) and cladding is certainly a point on that continuum.
Cladding, while of similar intent, differs from gluing or fusion welding as a method to fasten the metals together. Laser cladding, often used to increase corrosion resistance or improve mechanical properties, is a process in which a powdered material (normally of a metallic nature) is melted and consolidated by use of a laser. One example of laser cladding is that of the United States Mint, which uses cladding to manufacture coins from different metals (reducing costs by using cheaper metals used as filler). The precision of laser cladding has become integral to improving the surface and proximate surface properties of a part (e.g. wear, corrosion or heat resistance), or resurfacing a component dulled through natural wear-and-tear (Source: Coherent laser cladding applications).
Research in the area of cladding machines is venturing into automating them. In the process of cladding, process parameters must be manually set, but this might change as organizations look to develop sensors capable of measuring the process online. The geometry, temperature information, and metallurgical properties could be monitored by these sensors, if successful, which would eliminate the manpower required to produce the final product. Coherent lasers (their HighLight D-Series), relied upon for their superior quality, use a High Power Direct Diode Laser (HPDDL), which is highly absorbable for most metals. Their design enables large areas to be processed rapidly.
About the author: Mark Williams is the author of this blog post about the alchemy of laser cladding. He is an engineer and has gathered sources from http://www.coherent.com/applications/index.cfm?fuseaction=Forms.page&PageID=311 to write this post. Feel free to connect with him over at Google+