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10.22. A cylindrical riser with diameter-to-length ratio 1.0 is to be designed for a sand casting mold. The casting geometry is illustrated in Figure P10.22, in which the units are inches. If the mold constant in Chvorinov’s rule = 19.5 min/in’, determine the dimensions of the riser so that the riser will take [JIS] min longer to freeze than the casting itself Ve Vegade , Vins cet Vey Vote Vighadars Voure - View = w(4Y'G)-7 Cre) > Vouni-tiecle* xasyO) = us zu Vege £ (1875 \Cs) C12 2-5 Wares 3) S00 6 Ve Bee aside Vin aany Toasting 19.5 C 20536 ) L wary Ts 145 C “Ae | * 0.5 practice Page 1 al SAC grabs? dachrdac® Gost (List? In vi25) 496 Sx. $309) & 2E60)13000} 2 t - (ON) Bya)s La (2sy) Volume oF Wyn ner (Q.sn(3) + 5x4) i 2203.36 sa" Veisar? * cyt “xd q zn Cet) Ts 19.5 Ct0536 } * 0.5 ay ~ Cot) 2.3] “a 4 Argue and fr2n( eye ‘ sate noe vy #8 sce 41g ft)” bdr” gatealt t asi \as¢) _@ a 6 Fas id ~2-0b yn 17 3. Calculate the volume, diameter and height of the cylindrical rise required to prevent foaran shrinkage in a 4in x10 in x 20 in casting if H/D of the riser is 1.5. (15 points) h Zz Kets his hegota® C4) Ba (2054) 2 Osnd* + Ilsnd® Pa Ind® asda? V ands 1 (4y (1.5 a) on = ounrsd a \a = dt (1. "GCs z= oyiad Sheegag? L( 400)4 (2) + f0(20)) aikeg i ) 400 : eS) 440 V casing Gxio*l0 * YOO en rae 119616 practice Page 2 Mm, EUS a ty = =Gs)(2) ( x) a) Estimate the machining time required in rough turning a 1.5-m-long, annealed aluminum-alloy round bar 75-mm in diameter, using a high-speed-steel tool. b) Estimate the time for a carbide tool. Let feed = 2 mm/rev. Solution: From Table Annealed aluminum alloys maximum cutting speed 4 m/s using high-speed steel tools 7 m/s for carbide tools For high speed Steel Vina = Na D or N = V,,,/ 1 D = 4/ 2(0.075) = 16.97 rev/s or N= 1018 rpm. For carbide tools N= Vg / 1D = 7/ 20.075) = 29.73 rev/s or N= 1783 rpm. T,, = L/fn = 1.5/(0.002)(1018) = 0.74 min or 44s (HSS) T,, = 1.5/(0.002)(1783) = 0.42 or 25s (carbide tool) A 150-mm-long, 75-mm-diameter titanium alloy rod is being reduced in diameter to 65 mm by turning on a lathe in one pass. The spindle rotates at 400 rpm and the tool is traveling at an axial velocity of 200 mm/min Calculate the cutting speed, material removal rate and time of cut. material removal rate L750, B21 wan 0,2 0S mn N= 4od 1 4,- 200 nwolrni practice Page 4 ve Ne Qyz 40°" (5) practice Page 5 
