A wide variety of coating methods and materials are available for different coating applications with a common purpose of protecting a part or structure exposed to mechanical or chemical damage. A benefit of this protective function is to decrease manufacturing cost since fabrication of new parts is not needed. Available coating materials include hard and stiff metallic alloys, ceramics, bio-glasses, polymers, and engineered plastic materials, giving designers a variety freedom of choices for durable protection. To date, numerous processes such as physical/chemical vapor deposition, micro-arc oxidation, sol–gel, thermal spraying, and electrodeposition processes have been introduced and investigated. Although each of these processes provides advantages, there are always drawbacks limiting their application. However, there are many solutions to overcome deficiencies of coating techniques by using the benefits of each process in a multi-method coating. In this article, these coating methods are categorized, and compared. By developing more advanced coating techniques and materials it is possible to enhance the qualities of protection in the future.
Functional surfaces are of paramount engineering importance for various applications. The purpose of this review is to present counter-intuitive methods of fabrication based upon damage or instabilities for creating value-added surface functions.
In this experimental study, magnetorheological abrasive flow finishing (MRAFF) process is utilized to observe the effect of different finishing parameters on final surface finish quality. Ability to control over rheological properties of magnetic abrasive medium in MRAFF with exerting an external magnetic field let us reach internal surface finishing process due to its special rheological behavior. A new finishing set designed and manufactured to meet needs for these experiments that consists of a hydraulic-mechanical power unit, abrasive fluid containers, permanent Fe-Nd magnets, workpiece fixtures and a base frame. Finishing fluid in this study contains iron particles as magnetic bonders and SiC particles in different mesh size as abrasive part. In addition, a specific volume percentage of liquid paraffin and glycerin constitute base medium. Experiments were conducted on austenite stainless steel pipes in different magnetic field strength, abrasive particle size and finishing cycle time and were designed in full factorial mode. With increase in magnetic field strength and abrasive particle size, an increase in surface roughness is obviously observed but with increase in finishing cycle time, a different behavior is seen.
AbstractIn the precision thermoforming process, one of the main drawbacks occurs in the profile deviation of the produced part. In this study, the effect of different thermoforming process parameters on the mold replicability of a high impact polystyrene container produced by vacuum forming and drape forming processes has been experimentally and numerically investigated. According to experimental results, in the drape forming process, when the initial sheet thickness increases, the part will have higher mold replicability, whereas in the vacuum forming process, by increasing the initial sheet thickness, the mold replicability increases and reaches its peak, then decreases. The results also indicate that both temperature and vacuum pressure exhibit the most significant effect on mold replicability of the part. Furthermore, the finite element method is utilized by the implementation of a fully thermomechanically coupled hyperviscoelastic constitutive model in ABAQUS 6.13. By using this material model, it is possible to compare the sensitivity of the output (mold replicability of the part) to the changes in the range of the process parameters. The simulation results verified by the experimental data and the hyperviscoelastic model showed to be an outstanding and stable platform for the process simulation.
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