Fan gate

Fan gating system through seal outside diameter. 

In addition to the above formulation, they used two-noded elements to represent the runner system. Figure 9.29 presents the finite element mesh employed by Wang et al. [18] with the dimensions and location of the pressure transducers used to record pressure during mold filling. The fan gates were of variable thickness as pointed out in the figure, and the mold cavity was of constant thickness. 

Figure 6. Fan-gate. Material-flow into the mold.

Fan gate A shallow gate becoming wider (and usually thinner) as it extends from the runner to the cavity. 

The velocity of the flowing material in the area of the fan gate should not be greater than 1 5m s" otherwise the liquid will enter the mould cavity in a turbulent manner. This velocity value holds for polyol viscosities of 100-600 cP at 25°C. For lower viscosity materials, the film gate cross-section must be increased or the throughput decreased to maintain laminar flow. 

Fig. 6.8. RIM fan-gate design. (Courtesy of W. Becker (1979). Reaction Injection Moulding, Van Nostrand Reinhold, New York).

A fan gate spreads out from the runner to fill a wider edge of the part the gate thickness decreases gradually and is shallowest at the entrance to the part. Fan gates provide uniform flow into parts where warpage and dimensional stability are important. 

Figure 1 Gate design for tensile bar mold (Gl) Double Gated (G2) Single Gated (G3) Fan Gate...

Figure 2 Voids in molded part for the fan gate and end gated molds...

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