Abstract:
The energy dissipated in hard machining operation is converted into heat which
raises the temperature in the cutting zone. With the increase of cutting temperature; tool
wear, surface roughness, dimensional inaccuracy increases significantly. Various
researchers worked on various techniques to effectively control the increased cutting
temperature as well as tool wear rates, and surface integrity. The cutting temperature,
which is the cause of several problems restraining productivity, quality and hence
machining economy, can be controlled by the application of high-pressure coolant (HPC)
jet. High-pressure coolant (HPC) jet cooling is a promising technology in high speed
machining, which economically addresses the current processes, environmental and health
concerns. The benefits of reduction in machining temperature are reduction in cutting
force, tool wear and surface roughness. This benefit of HPC cooling depends on the
process parameters and cutting tool.
In this research work turning of AISI 1040 hardened steels (40 HRC, 48 HRC, 56
HRC) with HPC condition has been investigated and its performance is evaluated on the
basis of chip morphology, surface finish, flank wear and cutting temperature. An effort is
made to investigate the effect of cutting parameters (cutting velocity, feed and depth of
cut) and the cutting environment on cutting performance. The cutting oil has been
delivered through a specially designed and developed nozzle in such a way so that it can
deliver oil jet at critical zones during hard turning. An investigative comparison with dry
and HPC under same conditions has been done to evaluate the relative performance of
hard turning with HPC jet. A model of tool wear was also developed for specific working
condition. The model is developed to estimate the amount of principal flank wear with
machining time for any one of the tool-work combinations and cutting environments. The
experimental results indicate that the performance of the machining under HPC condition
is quite good and more effective compared to machining under dry condition. With the
help of the experimental results, model of principal flank wear has been developed to
understand the basic phenomenon in metal machining. Finally the model was validated
with experimental results to make it an acceptable model.
