Mold construction, openings

Figure 5.84 Examples of simplifying mold construction to produce openings without side action movements.

Loose punch A male portion of a mold constructed so that it remains attached to the molding when the press is opened, to be removed from the part after demolding. 

Mold inserts (cores, etc.) that are removed each time the mold is opened will affect mold construction by introducing wear points. Fixed inserts that must be interchanged less frequently are preferred. 

The ring-opening metathesis polymerization of dicyclopentadiene was monitored by ultrasonic spectroscopy.16 The thermoset poly(dicyclopentadiene) is formed by ringopening and cross-linking in a reaction injection molding system. A reaction cell with a plastic window was constructed for use with pulse echo ultrasonic spectroscopy. Realtime measurements of density, longitudinal velocity, acoustic modulus and attenuation were monitored. Reaction kinetics were successfully determined and monitored using this technique. 

In ancient times, clay was used for food and water container construction. Civilizations in the Middle East understood the techniques of ceramics as early as 5,000 B.C. The first ceramic vessels were made by pinching. In addition to containers, small figurines were molded. The pinching method did not allow large item construction. Slab construction, rolling clay into a sheet so the clay could be cut in pieces, opened the door for crafting a wide variety of objects. 

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