Casting Geometry

To rectify the defects like gas and shrink porosity within the casting; casting geometry is used as a tool. A foundry engineer studies the geometry of the part and plans to control the heat removal process within the casting structure and to improve the eminence of the casting. However, to identify the best possible geometry to adhere to solidification shrinkage requirements of the casting is required.

Identifying the best possible geometry can be an easy task in some alloys and can be a real difficult task in others where high technical design is required. In such case, where obtaining geometry requires skilled jobs, the foundry engineers work on “thermal trickery” to draft flow of energy in the form of fluids, and capture heat transfer patterns.

Though thermal trickery proves to be the best solution for resolving casting issues, but it is an expensive solution. By avoiding the use of this technique and generating error free castings with good designs, cost-less production can be obtained. Hence, casting geometry must consider both processing and functional requirements.

Earlier, sending blueprint to the foundries were the only method of producing casting geometry. But due to advances in the technologies and development of computer software’s, designing and analyzing such complicated issues has become a simple job. Features like increasing firmness of components and dropping the stress within these components can be designed with greater ease. With these software tools, the power of making metal casting geometry has become more reachable to design engineers as they have another significant ability to visualize the graphs in three-dimensional figures.

There are various physical and mechanical characteristics, which affects the geometry of the castings. The physical characters effecting geometry of the designs are life of the fluid being used, shrinkage of the component while undergoing shrinkage process, slag formation affinity and pouring temperatures.

All of these characteristics vary amongst different properties of different alloys. Apart from physical characteristics, few mechanical characteristics too affect the geometry of the design castings. They are modulus of elasticity and section modulus. Modulus of elasticity is mainly the measurement of stiffness of the material and hence contributes to elastic properties of the material. However, section modulus is the function of shape of the material designed for casting.

Geometry planning works as an influential tool on casting designs. The features, which are mainly affected due to casting geometry, are:

• Defects and lead time while producing a casting which forms the casting capability of the alloy
• Physical firmness of the casting

If the geometry is properly planned and studied, it can effectively reduce the defects arising in the casting designs. A well planned geometry with carefully drafted physical and mechanical characteristics as discussed above have the power to counterbalance the problems of poor fluid life, shrinkage, temperature maintenance, and slag formation tendency.

• It avoids defects, post casting quality checks, and rejected castings – A proper geometry planning ensures a control over temperature effects, strengths like compressive strength, impact strengths and tensile strengths. And show fair resistance to hot cracking and solidification shrinkage.
• Increases energy efficiency and reduces environmental impacts
• Saves energy – an effective geometry design influence the magnitude of energy consumption for cooling and lighting temperatures used in the process.
• Improves overall quality and life of casting - with the reduced defects and lead-time to produce a casting, the overall quality of the casting is affected and thus increasing its operational life.