PARAMETRIC INVESTIGATION AND FABRICATION OF A LOW-COST ABRASIVE JET MACHINING SYSTEM FOR PRECISION GLASS DRILLING

Abstract

Abrasive Jet Machining (AJM) is a non-traditional, contact-free material removal process in which a focused, high-velocity stream of fine abrasive particles entrained in a pressurized carrier gas impinges on a workpiece surface to achieve precise material removal. Despite the growing industrial demand for cost-effective, damage-free drilling of brittle and heat-sensitive materials such as soda-lime glass, the fabrication and parametric characterization of low-cost AJM systems suitable for small-scale and laboratory settings remain underreported. This study presents the systematic design, fabrication, and experimental evaluation of an indigenous, pneumatically driven AJM apparatus capable of precision glass drilling at operating pressures of 4–5 bar. Key process parameters—including supply pressure, nozzle-to-workpiece standoff distance (SOD), abrasive particle size, and nozzle orifice diameter—are examined with respect to their influence on the drilled-hole dimensional accuracy and material removal rate (MRR). The system employs aluminum oxide (Al₂O₃) abrasive of 50 µm mean grain size delivered through a tungsten carbide nozzle of 1 mm bore diameter. Experimental results indicate that MRR increases monotonically with supply pressure, while dimensional accuracy of the drilled cavity degrades beyond a critical SOD of approximately 12 mm. The fabricated prototype demonstrated consistent, crack-free through-holes in 3 mm soda-lime glass at a cycle time substantially lower than equivalent laser ablation setups, at a fraction of the capital cost. The findings provide design guidelines for practitioners seeking affordable yet accurate glass micro-drilling solutions in manufacturing and research environments.