ANALYTICAL AND EXPERIMENTAL STUDY OF INVESTMENT CASTING WITH LASER STEREOLITHOGRAPHY MODELS by Wen-Long Yao This dissertation presents an analytical and experimental investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography (SLA) patterns. Included in the consideration are the cracking temperature of the ceramic shell...

Several investigations have examined magnesia-based investments for pure titanium casting. However, the thermal expansion value was insufficient at low casting temperatures and high interfacial reactivity occurred at high casting temperatures. The purpose of this investigation was to modify a magnesia-based investment by adding a heat-resistant mold material, zirconia, in different ratios to pr...

Subsurface hook formation during initial solidification in the continuous casting mould degrades the quality of steel slabs owing to the associated entrapment of argon bubbles and non-metallic inclusions. To minimise hook depth and to improve slab quality, extensive plant experiments were performed and analysed to quantify the effect of casting parameters on hook characteristics using the no. 2...

In this paper, we propose a fuzzy aggregate production planning (APP) model for blending problem in a brass factory which is the problem of computing optimal amounts of raw materials for the total production of several types of brass in a period. The model has deterministic and imprecise parameters which follows triangular possibility distributions. The brass casting APP model can not always be...

The investment casting of TiAl alloys has become the most promising cost-effective technique for manufacturing TiAl components. This study aimed to investigate a series of problems associated with the investment casting of TiAl alloys. The mold filling and solidification of this casting model were numerically simulated using ProCAST. Shrinkage porosity was quantitatively predicted by a built-in...

Increasing use of aluminum shape castings in automotive and aerospace industries has drawn great attention to fatigue properties of cast aluminum components. The fatigue resistance of aluminum castings strongly depends upon the presence of casting flaws and characteristics of microstructural constituents. The existence of casting flaws significantly reduces fatigue crack initiation life. In the...

A feasibility study of the partial squeeze and vacuum die casting process was performed to make defect-free casting products with excellent mechanical properties. The trial die casting process in this study was industrially implemented for producing a reaction shaft support made of a hyper eutectic Al±15%Si alloy. To combine the squeezing and vacuum effect, the plunger injection system was desi...

This paper considers a ray-casting point-in polyhedron test. Although it is conceptually the simple extension of a well-known point-in-polygon ray-casting algorithm, various practical problems appear in 3D, especially, when the boundary of a geometric object is represented as a triangulated surface. When a larger number of points have to be tested regarding their positions on the considered geo...

Nozzle clogging is a serious productivity and quality problem in continuous casting. This work reviews the causes, effects, and solutions to clogging in continuous casting nozzles. The results of a one-dimensional, steady state analysis of the heat loss from the molten steel stream through the nozzle wall are discussed. The analyses show that steel may freeze within the clog matrix for a relati...

The importance of smooth mould filling in the foundry casting process has been recognized for a long time. More uniform the filling process is, the better the quality of the casting of the products produced. Successful computer simulations can help to reduce the number of trials and cut down the lead time in the design of new casting products by better understanding the complex mechanisms and i...