The impact of honing process parameters on the surface quality of cylinder liners
Abstract: During recent years, legislation regarding emissions and fuel consumption levels for the automotive industry has become increasingly comprehensive. In order for automotive manufacturers to reach the demands, engine friction needs to be reduced. The cylinder liner is considered to be one of the most critical engine components regarding friction and high demands are put their surface texture. No process has been found to create efficient cylinder liners as good as honing. Honing is an abrasive process, using three simultaneous movements of abrasive stones to remove material and create grooves. Since honing is an abrasive process, analytical prediction of the process outcome is difficult. In order to describe the process, empirical modeling has to be applied. The objective of this thesis is to, by using design of experiments, understand the honing process in the cylinder liner manufacturing at Scania CV AB and identify key parameters in the process control connected to surface roughness. Furthermore, the aim is to find an optimal setting of the machine to produce the demanded surface texture. Through screening experiments, five parameters were found to be the most significant in the process. These parameters were then further investigated in an optimization test. The results of this test showed that the plateau honing step was of main importance for the resulting surface texture. The factors with the largest impact were the honing force and number of strokes used in this operation. The results also suggested that the reciprocating speed influences the surface parameters and can be used to decrease the core roughness of the surface without affecting the valley depth negatively. Due to high correlation between surface parameters, compromises need to be made in order to find an optimal setting.
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