**4. Conclusions**

This study investigates the process of electroless and machinability of Ni-CBN on HSS and Carbide substrate. The electroless Ni-CBN coating has been successfully performed on the substrate and proven using the EDX Analysis. The EDX analysis revealed the presence of major peak for nickel (Ni), carbon (C), oxygen (O), boron (B), and phosphorous (P) elements on the HSS carbide substrate. According to the stability of the coating, 6 mm diameter HSS end mill was chosen. The coated HSS end mill thickness is 15 μm on average.

For machinability, Taguchi L9 (33 ) was used in this research to produce a Design of Experiment (DOE) using 18 runs number of experiments with three factors and three levels. The factors were spindle speed, feed rate, and depth of cut. The outcome of machining for surface roughness, tool wear and tool life was analysed by comparing the results between HSS coated and uncoated end mill. The comparison showed Ni-CBN HSS end mill produce good performance on the surface finish and is able to slightly reduce the tool wear and extend tool life.

Analysis of variance (ANOVA) was used for the optimisation parameters of the Ni-CBN HSS end mill tool. The Spindle speed is a significant factor compared to the other factors as it had the lowest P-value, that is below 0.05. For determination of optimum parameters, 1860 RPM for spindle speed, 334 mm/min for feed rate, and 2 mm for depth of cut were identified as the optimum machining settings. The experiment was validated through the S/N ratio using the optimal parameter level A1B3C2.
