Gating Systems
Casting Lab 3: Gating Systems and Fluidity Introduction The purpose of the lab was to compare the difference in cross sectional areas, sprue size and location in gating systems as well as the totest the influence of the molten aluminum temperature had on the fluidity of the mold. We investigated which areas in the gating system filled, the time it took to pour the metal, the temperature effects on the fluidity. These tests are important when designing the mold, also when choosing which metal will be poured because each pours differently. Key variables include the sprue diameter, and location. The runner and gate area as well as the temperature and the type of flow (unpressurized or pressurized), and the fluidity number are all important variables. Results Table 1: Data Sheet for Gating Table 2: Data Sheet for Fluidity Discussion There were two gating systems used in this lab. The first mold was an unpressurized system while the second mold was a pressurized system. In an unpressurized system the total in-gate cross-sectional area is greater than the sprue cross-sectional area which will have a tendency to slow down the velocity of the flowing metal and erosion and turbulence will also be decreased. In a pressurized system the total in-gate cross-sectional area is less than the sprue cross-sectional area. With a pressurized system the velocity seems to be higher and erosion and turbulence are also increased. This system also allows a more uniform flow through the in-gates. The pressurized mold had a slower pouring time compared to the unpressurized system, but had a weight of flow that was more distributed through the gates as it should. The fill order of the pressurized system was almost in order from gates 1-4 while the unpressurized system was more scattered. This order also results from the location of the sprue. When deciding what gating method is appropriate one must look at a couple of factors such as type of metal being poured and the
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