Effect of grain size and number of strokes on Rk parameters and emptiness coefficient in honing process

This paper deals with evaluation of the effect of grain size of abrasive particles and number of tool strokes on the roughness values (Rk, Rpk, Rvk, Mr1, Mr2, and Rp/Rt ratio) in flexible honing. The grain size factor was investigated on two levels (400 and 800 mesh) and the number of tool strokes on three levels (1, 3, and 5) based on a full factorial design 2x3. Flexible honing was performed after conventional honing, on 30 crankcase cylinders of hermetic compressors made in gray cast iron. The analysis of variance technique showed that the effect of abrasive grain size on the roughness was more significant than that produced by the number of tool strokes. The abrasive grain size caused statistically significant effects on Rpk, Rk, Mr2, and Rp/Rt, whereas the number of tool strokes affected Rpk only. The interaction between these factors affected Rk. The flexible honing process using 800 mesh tool grain size and five tool strokes allowed for the obtainment of surfaces similar to those that resulted from the plateau honing operation. This result can increase the field of application of this process. Flexible honing was not able to remove the waviness present on the crankcase cylinder surfaces, whose amplitude was similar to those presented by the roughness.