Mold types Removable plate

Many problems may be encountered in thermoforming, some of these are related to plasticizers or they can be eliminated by changes in plasticizer type and amount Problems related to plasticizers include die lines or dull spots (plate-out buildup), dark specs and streaks (polymer degradation), excessive sag, distortion after part removal, warpage, poor wall thickness distribution, and part sticking to mold. 

In this type of insulated runner mold design, the runner plate and cavity plate are bolted together and are only opened to remove the solidified runner after breaks in the molding cycle or to remove fireeze-ups. 

Preactivated and Water-Activated Types. A typical preactivated industrial-type zinc/air cell, the Edison Carbonaire cell, is manufactured in a 1100-Ah size and is available in two-and three-eell configurations, as illustrated in Fig. 38.12. The cell case and cover are molded from a tinted transparent acrylic plastic. The construction features are shown in Fig. 38.13 identifying the wax-impregnated carbon cathode block, the solid zinc anodes, and the lime-filled reservoir. These cells normally have a bed of lime to absorb carbon dioxide and to remove soluble zinc compounds from solution and precipitate them as calcium zincate. They are made with transparent cases so that the electrolyte level and the state of charge can be monitored visually. The state of charge can be monitored by observing the condition of the zinc plates and the condition of the lime bed. The bed turns darker as it is converted to zincate. 

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