. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Casting innOVatiOns
of metal. These voids were discov- ered when the parts were machined. Prior to the use of QuikCast soft-
ware, the metalcasters added a core in the hub to reduce the amount of liquid metal required to feed it dur-
ing solidification. The open riser was replaced by a tall closed riser. After casting and boring, the hub of the im- peller exhibited no defects, but a new shrink defect began to appear in the wear ring section, a heavy circular rib about an inch from the hub. “By viewing the [QuikCast] simula-
tion results, I was able to determine that the new shrink defect resulted because the hub section was now solidifying much more quickly,” Ru- dolph said. J. Walter Miller applied design
changes to the CAD model of the casting that included removing the core in the hub to allow a feed path to the wear ring. Subsequent simulation showed the new design eliminated the shrink in the wear ring while the shrink porosity in the hub was confined to the center-most region that was removed during the machining process. “This problem would have taken
Prior to the use of Quikcast simulation, J. Walter Miller Co. used a closed riser and cored hub design, which produced a shrink pocket in the wear ring.
about 12 weeks and $6,000 in pat- tern changes plus countless hours of machine time to solve using conven- tional trial and error methods,” Ru- dolph said. “With casting simulation, we can easily solve similar problems in two weeks and produce a good pattern the first time.”
METAL
Using solidification simulation, the metal- caster determined that a design incorporat- ing a solid hub and open riser would elimi- nate the shrink pocket in the wear ring.
50 Metal Casting Design & PurChasing January/February 2010
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60