Gates, transfer moulding

Lui B, Bickerton S, Advani G. Modelling and simulation of resin transfer moulding-gate control, venting and dry spot prediction. Compos Part A 19% 27a(2) 135—41. 

The pack pressure (see Figure 7.38) is applied for a preset time, which determines the mass of the moulding the system then transfers to the lower hold pressure until the gate freezes. After a set time at hold pressure, the screw rotates and moves backwards. During this phase (in order to achieve consistent melt viscosity from shot to shot) the back pressure is held at a low but constant value. 

Note For optimum holding pressure transfer the moulded part should be gated to the largest cross-section. In order to avoid premature solidification of the sprue and gate system, sufficient dimensioning is necessary. 

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