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SPECIAL REPORT I MATERIAL COATINGS


Wheel of fortune Meister Abrasives’ cDD dresser technology: One dressing tool for optimal truing and sharpening


Meister Abrasives explains how its vitrified diamond bonded wheel technology is helping customers obtain the combined wealth of increased productivity and cost- effective HVOF grinding processes.


to the environment. As a result, they are being phased out and replaced by high velocity oxy-fuel (HVOF) coatings, an advanced thermal spraying application process that imparts excellent wear and impact resistance. To meet the demands of the aerospace sector, Meister


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Abrasives’ vitrified diamond bonded wheel technology can efficiently grind HVOF hard coatings, resulting in a process that is consistent and applicable to many components, such as those used in landing gear. As a high velocity, high temperature thermal spray


technique it is capable of depositing corrosion and wear resistant materials such as tungsten carbide or chromium carbide in a layer that is dense, strong and hard. HVOF coatings can be up to 90% harder than the ones they replace at 750-950HV/0.3 or around 62-65HRc, so they provide superior protection to critical wear components. These are the positives that HVOF can offer. However, the difficulty is that HVOF coatings require aggressive machining to bring their rough irregular surfaces to final geometry and finished tolerances. Without this rapid wear can be caused to mating


he conventional hard nickel and chrome electroplating processes employed to harden or repair aerospace components produce emissions that are very harmful


parts or seals that come into contact with the surface. To grind HVOF components productively and at optimal


cost, three things are required. First is an ultra-rigid, well maintained CNC grinding system with automated rotary dressing. Second, the process requires a carefully selected diamond abrasive grinding wheel, and finally optimised grinding parameters. There are many examples of companies that have obtained


these HVOF grinding prerequisites working with Meister and one of these is Complete Grinding Solutions in the USA. This company has developed numerous prototypes and transferable grinding processes for HVOF-coated components for various industries including aerospace. While the specifics of the grinding processes Complete


Grinding Solutions develops for its customers are confidential, the company will divulge that Meister Abrasives’ vitrified diamond abrasive specification has been used in all of its HVOF grinding projects to date, regardless of the coating formulation, size of the part or even the size of the wheel. Meister Abrasives UK’s sales and marketing director Paul


Batson says that the company has also been successful at grinding HVOF in the UK. The grinding processes are completed in a single set-up and totally automated. The


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