You remember that it is necessary to start a pattern of mold making and we’ll see some examples of patterns in the next slides. However, you should also remember that the hollow interior of solutions by heart – this can be remembered by analogy with an apple core. Such shapes in sand made in a special sort of a pattern called core box. We’ll see some examples of cores produced from core boxes in this section. As a final note before we start the slide, should you notice in places that the distinction between molds and cores hazy in the process of assembly central, with large blocks of sand made into boxes, as the core, but with combined together to form a mold.
Making shapes sand in hard, chemically-bonded sand important field of foundry technology. Figure we see here the core machine to the Foundry Caterpillar in Peoria, Illinois, using the process Isoset Ashland. This allows core sand (silica sand mixed with two-part binder comprising phenol formaldehyde resin and isocyanate reactive) be blown in core box and then hardened by passing amine catalyst in a gas carrier through. Thus the heart is more-or-less fully hardened by the time it is ejected out of the box. Provides high productivity and high precision. Producing large mold halves in chemically-bonded sand-set itself at the Foundry Pryor, Oklahoma, showing the superb engineering required for models of this size to turn. Figure shows the process in which no binder is used to bond together on the sand. The mold is sealed on to the front face with a thin film of plastic and vacuum used to hold the grains of sand in place.
The model has just been stripped off the pattern, can see red colored below. The vacuum molding process, usually abbreviated Talat is not the V-3201 11 process, which is widely used in Europe, but is popular in Japan where it was invented. Can the high quality and smoothness of the mold face can be seen directly in this opinion. Figure series of chemically-bonded sand cores ready for assembly to mold cylinder head to the engine Rover Series K. The high quality of the cores 3201 12 Talat clear and allows the technique to build extremely precise models. The technique is called the Core Assembly Process.