R. Mccullough, R. J. Molz, D. Hawley, Sulzer Metco, Westbury, NY
Various methods of calculating coating costs and process performance have been used throughout the development of thermal spray processes; each tending to be unique to each process or coating method. Comparison of the effective performance of each process, in relation to each other, is hampered and difficult to compare on an equal basis. A more generic and global method is presented, based on deriving a unified process efficiency formula that takes into account all energy inputs and energy outputs of a process in the same energy units. Applying the coating process specifics such as deposit efficiency can then be used to determine a unitized process cost in terms of energy required and subsequently process cost. This method permits direct comparison of process efficiency for each process and specific coating conditions, promoting the advancement of more efficient and controlled thermal spray processes. Example of the results are the surprisingly low process efficiencies, less than 5%, for processes that use higher energy levels, and the highest efficiency recorded by Arc wire at nearly 30%.
Summary: A generic method for evaluating the performance of a thermal spray process based on the energy input to the process versus the energy utilized to produce a coating. Method can be used on any thermal spray process to enable comparison of effective perofrmance when more than one process or coating method might be possible for a given application. Economic costs can then be derived for a specific coating. Thermal spray processes are relatively inefficient and range from less than 1% to as high as 30%.
