Fuzzy contact and its effect on thermal damage in grinding processes

In abrasive machining processes, the contact between the abrasive tool and workpiece is very rough, which affects the cutting efficiency and surface integrity of the component machined. The contact behaviors between the grinding wheel and workpiece in grinding were investigated. The grinding forces, surface topography of the wheel and workpiece and the ratio of real contact area to apparent contact area in grinding contact zone were studied. It revealed the ambiguity in deciding the size of the contact region from a measured contact signal. For better represent this fuzzy contact phenomena, fuzzy set theory was used. A membership function for the fuzzy representation of the extent of wheel-workpiece contact was developed. The membership function was quantified using the measured contact signals and grinding theory. The fuzzy representation and membership function, as a case study, was used in the grinding thermal modeling. It showed that the predicted temperature from the new fuzzy thermal model was much closer to the real grinding temperature measured than from the conventional thermal model. This work shows how fuzzy theory make it possible to address problems that lie beyond the reach of traditional methods.