MEC 431 Lecture Notes - Lecture 22: Jet Stream, Electroplating, Aluminium Oxide
8 Jan 2018
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Lockheed sr-71 blackbird mach 3. 5 spy plane once flown from ny to. London in under 2 hours 85% titanium air frame. Ref: http://www. wired. com/thisdayintech/2010/09/0901sr-71- be accomplished by conventional machining conventional methods machining blackbird- transatlantic-record/ Disadvantages: wear on nozzle, life of high pressure pumps (cid:523)60,000-90,000psi) Abrasive water jet cutting: when wjc is used on metals, abrasive particles must be added to jet, additional process parameters: abrasive type, grit size, and flow rate. Abrasives: aluminum oxide, silicon dioxide, and garnet (a silicate. Grit sizes range between 60 and 120. Grits added to water stream at about 0. 25 kg/min: (igh velocity stream of water containing small abrasive particles (0. 5 lb/min) after stream exits nozzle. V = traverse speed in ipm fa = abrasive factor (1. 0 for garnet) P = stagnation pressure of waterjet in kpsi, typically 50,000 psi m = material machinability d = orifice diameter in inches, typically 0. 014 in. Ma = abrasive flow rate in lb. /min. , typically 0. 8 lb. /min.
