Simulation Study on Wax Injection for Investment Casting

Abstract

As investment castings grow in size and complexity, control of wax pattern dimensions becomes increasingly important and difficult. Conventionally, mold design and dimensions are re-worked by trial-and-error procedures until casting dimensions are produced within acceptable dimensional tolerances, increasing the cost of the castings.Nowadays, numerical simulation is an efficient tool for mold design. However, one of the critical difficulties in using computer models for the simulation of wax injection process is the lack of material properties of the wax. Material property measurements were conducted in this study that can be used as input in Moldflow. Then, 3D numerical simulation could be applied in analysis with mold design of thin-walled wax pattern, with high dependability. Simulation results of filling time and the location of the air traps were analyzed. Consequently, best gate location and reasonable gate system were determined. The paper highlighted the effectiveness of simulation in filling optimization and deformation of wax pattern.

Solvothermal Synthesis, Structure, Fluorescence and Magnetism Properties of a Novel 3D Metal-Organic Framework Based on Tetranuclear Copper Secondary Building Units

“…6b). All these features indicate the occurrence of a dominant anti-ferromagnetic interaction between the Cu(II) centers [29,30,34].…”

“…The values of χ M increase to a first maximum of 0.007 emu•mol -1 at about 65 K, then decrease rapidly to the minimum of 0.003 emu•mol -1 at about 14 K, and finally increase again rapidly with the decrease of temperature. The temperature dependence of the magnetic susceptibility obeys the Curie-Weiss law χ M = C/(T -θ), [C = 0.125g 2 ∑S(S + 1)] between 300 K and 65 K. The 1/χ M vs T plot gives Weiss constant of θ = -124 K and Curie constant of C = 1.56 cm 3 •kmol -1 and g = 2.03, while the increase of χ M below 14 K is attributable to the presence of paramagnetic impurities [34]. On the other hand, the effective magnetic moment (µ eff ) at room temperature is 3.075 µ B , which is slightly lower than the spin-only value of four uncoupled copper (II) S = 1/2 ions (µ eff = 3.464 µ B with g = 2.00).…”