FEA for coatings.

When utilizing finite element analysis (FEA) it is possible to simulate a design concept and determine its real-world behavior under a number of different factors. It facilitates the prediction of fluid flow, heat and mass transfer, chemical reactions, and related phenomena. Providing excellent visual aids and simulations for human analysis, FEA can be used to certify a product, reduce the need for prototyping, and eliminate the need for expensive and time-consuming trial-and-error testing. Ultimately it means that the product life of a component can be accurately predicted.

Structural analysis is the most common FEA method. It simulates the application of varying "stresses" to a design concept. Every component has what is termed a "stress threshold" beyond which the component undergoes a permanent change in shape such as buckling. After analyzing the design concept, the data is used to optimize the design for maximum efficiency and one that functions efficiently throughout the period it is required to, under various boundary conditions--heat, stress and vibration--and can be manufactured at minimum cost. Thermal analysis is used to determine the temperature distribution, heat accumulation or dissipation, and other related thermal quantities such as an object's conductivity, radiation and convection. FEA is of particular importance to engineers because as an object heats up or cools down, its material properties change, influencing the structure and product life of the component.

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One company at the forefront of FEA methodology is HNK Tech which has research links in South Korea and the Innovative Manufacturing Research Centre (IMRC) at the UK's Bath University. "Dr. Hyun Jeon, who started HNK Tech Europe two years ago, developed this unique electroplating simulation technology," says company director Stephanie Pakenham. After graduating in South Korea, he came to the UK to do his PhD, where he researched and developed the product at Bath University. This led to his starting the company, almost as a spin-off, although it is quite separate from the university. "We have close links to the university but we are not part of it," says Pakenham. HNK Tech Europe provides its clients with complete FEA solutions which can either be delivered as a consultancy service or as a bespoke software application. In an upgrade to its services, it has now developed a simulation process that it considers unique.

Electroplating is an essential part in the finishing process of manufactured products, but more often than not, costly trial-and-error, grinding and polishing methods are employed to achieve uniformity. FEA simulation of this process is a way to solve this problem. This is achieved by mapping the current density field using finite element methods to determine the amount deposited on the discrete parts of the component. However, one of the difficulties is the skill level involved in FEA analysis but HNK Tech Europe claims that its customized user interface (CUI) is a solution as only limited training is needed to be able to build a FEA model. The component is modeled on the variables, for example, voltage and conductivity, that have been entered via the CUI with the mesh then applied to create the elements to be analyzed. FEA then occurs on the component, creating a density model of the deposited material. The results are reviewed and if required, the engineer can then re-run the model again, changing the variables in order to achieve greater uniformity.

As well as providing CUI for electroplating, HNK Tech also has the technology to provide highly accurate uniformity for other plating methods including PVD, plasma, plastic and spray coatings but not titanium. "What we start by doing is to analyze the company's coatings set up and how it works," says Jonathan Ridley, a marketing executive at HNK Tech Europe. He says that when they analyze how well a company is performing its coating operations, they typically find that the thickness and accuracy is 60% to 80% across the component. "We claim that with our process those figures are increased to 95% and that we can guarantee that the component is almost perfectly coated both in uniformity in thickness and accuracy." HNK Europe either sells software or performs consultancy services.

A good area for automotive applications is in bearings and piston rings, says Pakenham. "It is not just about which coating should be used where, but the level and degree of coating that needs to be applied to a particular component. It can be used by the manufacturers to improve the quality of their products and because of the simulation, the actual process and even the factory layout can be changed to accommodate what has been learned about the coating process.

"However, wherever a vehicle is coated, whether it is the body frame or individual coatings, our coatings simulation technology will help the OEM save both time and money," claims Pakenham.

By William Kimberley, European Correspondent, [e-mail]