A NOVEL METHODOLOGY IMPLEMENTED IN MODIFYING THE NOZZLE BY INCORPORATING MULTI START INTERNAL THREAD TO ACHIEVE HIGH MATERIAL REMOVAL RATE IN THE ABRASIVE JET MACHINING PROCESS

摘要

The present invention describes the abrasive jet machining with novel internal threaded nozzle. The nozzle of total length 50 mm comprises an inlet of diameter 18 mm and the nozzle tip of 3 mm diameter providing an initial conical funnel shaped structure to the said nozzle and followed by a cylindrical profile with internal threads is designed to achieve the object of the invention. The subsequent length of the said nozzle comprises a cylindrical profile of length 25 mm wherein the said cylindrical profile is internally threaded with the thread pitch of 3 mm. The whole structure of the nozzle is designed to form a shape of a funnel. The said nozzle is improvised by etching continuous threads along the internal surface of the 25 mm long cylindrical profile lying in the passage way of the air abrasive combination. The thread profile so introduced inside the extended surface of the nozzle induces a swirl motion to the air and abrasive particles apart from incrementing the angular velocity and pressure to the said combination prior to the machining of the test bed. A detailed CFD analysis discloses that when compared to the existing nozzle, the invented threaded profile increases the velocity rate, pressure and swirl motion of the air and abrasive particles to a considerable degree and the micro machining performed on glass fibre reinforced polymer composite material resulted in much faster and better results.