Abstract:
Minimum quantity lubrication refers to the use of cutting fluids of only a
minute amount-typically of a flow rate of 50 to 500 ml/hour-which is about
three to four orders of magnitude lower than the amount commonly used in
flood cooling condition, where, for example, up to 10 liters of fluid can be
dispensed per minute. The concept of minimum quantity lubrication,
sometimes referred to as near dry lubrication or micro lubrication, has
been suggested since a decade ago as a means of addressing the issues of
environmental intrusiveness and occupational hazards associated with the
airborne culling fluid particles on factory shop floors. The minimization of
culling fluid also leads to economical benefits by way of saving lubricant
costs and workpiece/tool/machine cleaning cycle time.
The aim of the present work is primarily to explore and evaluate the role
of MOL on grindability characteristics of some commonly used steels mainly
in terms of chip formation mode, grinding temperature and surface roughness
which govern the productivity, product quality and overall efficiency.
Considering the chip characteristics in dry and wet grinding, the
mechanism of chip formation is mainly due to shearing, ploughing and
rubbing. But in MOL substantially changed in mechanism of material removal
to predominantly shearing. It is also evident that the mechanism of chip
formation shift further from shearing to fracturing with increase in work
hardness.
Grinding zone temperature is reduced more in MOL compared to dry
and wet grinding. In MOL, surface roughness is lower than wet grinding but
higher than dry grinding. But plastic deformation, surface and subsurface
cracks are significant in dry grinding compared to MOL grinding. Thus MOL
improves the grindability characteristics.
