Mold types Stacked

Requirements Mold/Machine/ Periphery Mold type (e.g., normal, stack and multicomponent molds) Machine type (injection molding machine) Connection and periphery systems... 

Jiang and Zhu (2000) and Qiu and Zhu (2001) have reported the fabrication of multilayered devices composed of stacks of compression-molded disks of alternating compositions. One type of disk is either P(SA-EG) or P[SA-co-TMAgly)-Z>-EG] and the other is a pH-sensitive, protein-loaded blend of, for example, poly(methacrylic acid) and polyethoxazoline. The release of model proteins, myoglobin, bovine serum albumin, and FITC-dextran, and compounds such as brilliant blue have been studied and pulsatile release profiles have been demonstrated (Jiang and Zhu, 2000 Qiu and Zhu, 2001). 

The principal types are two-plate, three-plate, and stack molds. Others include the family mold that has multiple cavities of different shapes in one mold.3, 324 A further distinction concerns the feed system that can be either the cold or hot type. These classifications overlap. Three-plate molds will usually have a cold runner feed system, and a stack mold will have a hot runner system. Two-plate molds can have either feed system. 

Air is filtered for many types of particles, such as dust, molds, pollen, acid rain droplets, aerosols, stack gas particles, and bacteria. Figure 37-2, p. 432, shows an air filter using a sheet of paper, glass fiber, or plastic barrier. 

Fig. 2-7b. Types of injection molds illustrated here are insulated runner, hot manifold, and stacked (1).

These materials have been successfully molded in all types of mold, for example, 2-plate, 3-plate, insulated runner, stack and hot runner, en using the hot manifold type of runnerless mold, the runner channel must be streamlined so that there are no dead spots (nil flow areas) which are likely to cause degradation accurate temperature control of the manifold is essential. To maintain the sparkling clarity of this material, use vacuum smelted steel as this can take a very high polish and is non-porous. 

In this type of mold, production can be theoretically doubled providing that the machine capacity is high enough to flU both sets of cavities. The stacked mold consists of two sets of cavities, one on top of another. In this way high clamping pressure, which would normally be required with a mold having an increased number of cavities, is also minimized. 

Before use, the sheets are cut to size and the polyethylene stripped off. They are then placed in a heated compression-type mold (several layers may be stacked for greater thicknesses) where true cure (crosslinking) of the polyester takes place. 

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