Determining the Optimal Parameters for Grinding Microporous Coatings according to the Roughness Criterion

Abstract—Three critical challenges, namely, rapid wheel loading (clogging), reduced wheel life, and a severe deterioration in the surface roughness of the machined workpiece, arise during cylindrical grinding of thermally sprayed shaft journals in automotive and heavy equipment applications. Furthermore, faceting and cracks appear on the surface. The underlying cause of these phenomena is attributed to the unique physicomechanical characteristics of the coatings, including high porosity, the presence of oxides and slag inclusions, and elevated levels of adhesive and chemical activity. The study underscores that a promising approach to enhancing the efficiency of plunge grinding for coatings and attaining high technical-economic performance is the optimization of abrasive processing. This paper presents the results of optimizing the cylindrical plunge grinding process for microporous nickel-based coatings. A set of parameters required to optimize the grinding operation based on surface roughness criteria is established. A system of technical constraints is also developed to optimize cutting conditions and grinding wheel characteristics. The study addresses the challenge of achieving minimum surface roughness while maintaining specified grinding process parameters. A mathematical model of the grinding process is developed as an integral part of the optimization problem. The optimization of the objective function (surface roughness) is performed using linear programming. Optimal grain sizes and hardness grades for grinding wheels are determined to ensure the lowest achievable surface roughness. The proposed methodology can be used to determine optimal parameters for grinding microporous coatings on various repaired components, such as crankshaft and camshaft journals in internal combustion engines. Consideration of the complex process influencing factors ensures the minimum roughness after plunge grinding of microporous gas-thermal spray coatings.