A manufacturer of brakes found that iron was re-depositing in the pores of its clutch plates, giving them a frosty reddish cast. In their system, multiple vibratory machines derusted steel parts in a 1st stage, then cleaned and neutralized in a 2nd stage. The transition proved to be too extreme, causing iron from the pickling solution to precipitate into the steel. It could not be removed without etching.
Changing-out the pickling solution weekly could have been a solution, but the company rejected that option. Instead, they re-ran parts, then sent them to another department to etch and oil, at an annual cost of approximately $100,000.
It was determined that processing parts through a chemical bath which opened the pores of the steel, followed by a high alkaline, (which closed them again), then heated wash and cold rinse, was sealing in the iron oxide particles. A robust, workable solution, VBS 125, was identified. VBS 125 was developed by Finishing Technology Inc., a manufacturer of vibratory compounds and other mass finishing products. It eliminated the iron redeposition – and its attendant $100K price tag.
See descriptions of Finishing Technology vibratory compounds featured
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