Abstract:
Although MRR increases with increase in velocities and feed rates but it
raises tempcrarurc remarkably and such high cutting temperature adversely affects,
directly or indirectly, chip fonnation, cutting forces, tool life, dimensional accuracy
and surface integrity of the products. IWC (high pressure coolant) jet assisted turning
is an effective method of machining, which allows overcoming the problems
presented in the conventional turning of steels. The application of culting fluid with
HPC leclmique causes a hydr<iulic wedge between the chip and the r$e face of the
tool with very jXlsilive efiec( on machining which noticeably reduces the
temperarure gradient and eliminates the sei~ure effect, offering adequate lubrication
at the lool--<:hip interface with a significant reduction ill friction in addition to
alteration of the chip flow conditions resulting in the lowering of component forces
and consequently tool wear rate.
But, to get the greatest benefit from the HPC (High Pressure Coolant)
system it is very vital to use the optimum amount of pressure and flow, recognize the
type of nozzle or orifice to place at the end of the tube that will properly direct the
coolant stream, and &etting the correct angle and distance from the work piece
required to properly hit the exact high temperature wne of the cutting area. lbis
paper deals with experimental investigation on the role of HPC having various
pressure and flow rate by cutting oil (HC straight run, VG 68) on cutting
temperature, chip morphology, surface roughness in turning AISI.-4320 steel at
industrial speed-feed combinations by uncoated SNMG insert. Then, optimization
has been carried out with the help of Design of Experiment along with Multiple
Attribute Decision Making method and multiple graphical plots. The analysis of
results show that the optimal combinational effect of average chip-tool interface
temperature, chip reduction co-efficient and surface roughness can be achieved by
optimizing cutting speed, feed rate along \,ith the pressure and flow rate of HPC
coolant jet. Other significant effects such as the interaction between the process
parameters are also investigated. Finally, cutting forees (main cutting force and feed
force) and dimensional deviation has heen measured under HPC (having optimum
pressure and 'flow rate) and dry environment to compare with one another based on
forces and dimensional deviation. In total, the encouraging results include significant
reduction in temperature, force, dimensional inaccuracy and surface roughness by
APe application mainly through reduction in the cutting wne temperature and
favurablc cbange in the chip-tool and work-tool interaction.
