Mold filling dynamics

Abrasive effects are created due to dynamic forces formed at the collision of flow fronts where weld lines occur in the molded part. This effect is particularly strong at the end of mold filling, in the so-called compression shock . The extent of wear increases with the amount of abrasive fillers and reinforcing materials. The consequences are local mold surface roughnesses or washouts. 

Modeling the Fluid Dynamics and Heat Transfer of Mold Filling... 

In a more sophisticated analysis these functions can be found as the solutions of the dynamic and energy balance equations for filling a mold. 0m is the dimensionless temperature of the mold To is the initial temperature of the reactive mixture co = (H2kr,T)/a is the dimensionless factor characterizing the ratio of time scales for heat transfer and the chemical reaction. Other dimensionless variables are as follows ... 

Experiments were run to evaluate the effects of low level static (stretch) and dynamic (ultrasonic Irradiation) stress on water permeation of a WRT Neoprene. At the same time, the contribution of a partial silica filler In the place of black was determined. The materials were Identical zinc oxlde-magne-slum oxide-cured formulations except that one contained 30 phr black and the other contained 15 phr black and 15 phr silica. These were molded Into cups with 0.030 In. thick faces and 0.070 In. thick side walls which were then fitted over 3.5X salt water-filled glass cups and sealed with hose clamps. 

Figure 8.22 Effect of mold wall thickness on the dynamic mechanical properties of injection-molded bars of PCX (a) unfilled and (b) filled with glass fibers.

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