Simple Solutions That Work! Issue 10

The pressurization factor will increase the sprue area to ensure that the gating system remains pressurized, which is preferred for vertical gating systems. This next stage is the Pour Cup and Sprue Design window (Fig 2). The pour cup should have enough volume to accommodate one second of metal flow, with a minimum dimension of 2.5 inches (63.5 mm). These fields are display only; no data entry is required. For downsprue design, the program needs to know how many gates are fed from this sprue and the height from the top of the mold to the top of the sprue. This establishes the velocity and area at the sprue top. Include a generous radius at the transition from the bottom of the pour cup to the top of the sprue. Recommended design practice is for the area at the bottom of the sprue to be one- half that at the top. The next display is the Runner Design window (Fig 3). This is used if you have any horizontal runners in the gating system. The system needs to know how many gates are fed from this runner and the height from the top of the mold to the center of the runner. This establishes the velocity and area of the runner. 33 HOW TO Figure 1. Alloy Selection and Optimal Fill Time (OFT) Calculation. Figure 2. Pour Cup and Sprue Design. Continued on next page