Computer-aided development of an investment casting process

Abstract

Using computer modeling and results visualization techniques, the gating design for a precision investment casting was improved, and the possibility for casting defects was detected. This approach resulted in a potential seven percent cost savings on the component alone and eliminated the expensive trialand-error process. With continuing improvements in computer workstations and modeling software, it should soon be possible to dramatically reduce the effort required to generate and analyze finite-element models.

Casting-chill interface heat transfer during solidification of an aluminum alloy

“…at the interface. Following this, the time between iterations, One of the difficulties in modeling heat transfer during which is dependent on the thermophysical properties of the solidification is that of coupling microstructural and thermal steel and on the number of elements into which the plate phenomena, since it is expected that the heat-transfer coeffiwas divided, is given by [24] cient will be higher during the early stages of solidification than later on, mainly due to the air gap formed by metal ␦t Յ d 2 (m Ϫ 0.75) s 2mk [6] shrinkage. [13][14][15][16][17][18] Solidification of the aluminum alloy in contact with the steel plate was followed by thermal analysis; the 0.75 value comes from the assumption that the tempera- Figures 6 and 7 show the method used to obtain the critical ture distribution toward the surface follows a parabolic distripoints of transformation [19,20,21] in test II.…”

“…These thermocouples were connected to solid-state process is gained, reduction in production costs as the varidevices, which convert the electromotive force generated by ability of the process is decreased, etc. Foundries can achieve the couple into a linear scale ranging from 0 to 5 V. The the greatest benefits by implementing a direct approach to output from these devices was then fed into an analog-digital modeling, [4][5][6][7][8][9] in order to gain knowledge about the interacboard installed in a compatible computer. tion between the different phenomena that take place during Figure 1 shows, schematically, the positions at which the the solidification of complex pieces.…”