Experimental investigation and parametric optimization of cryogenic abrasive water jet machining of nitrile rubber using Taguchi analysis

Mining/marine bushings, biomedical implants, and many more are among the several applications of lightweight elastomer components. The use of non-traditional machining to manufacture these good-quality components in small or batch-size units is required because the primary manufacturing method requires customised mould and follow-up machining. In this regard, the present work focuses on investigating the performance of machining a nitrile rubber (NR) using suspension-type abrasive water jet (AWJ) under both conventional (room temperature) and cryogenic (liquid nitrogen (LN₂)) conditions at optimal values of process parameters: water jet pressure (WJP, bar), transverse rate (V_f, mm/min), and stand-off distance (SOD, mm). The experimental runs are designed using Taguchi analysis with respective performance parameters: Kerf taper ratio (KT_R) and Material removal rate (MRR, mm³/min). The results show that V_f (Rank 1) is the highest influencing factor on the machining performance of NR under both conditions. The reasons are improved kinetic energy, less collision of garnet abrasive particles and lesser change in the average width of the kerf. The influence of LN₂ showed that the optimal values of KT_R reduced by 11.97% at 200 bar, 40 mm/min, and 1 mm, and MRR increased by 0.65% at 250 bar, 60 mm/min, and 2.0 mm, respectively.