Читать книгу Plastics Process Analysis, Instrumentation, and Control - Группа авторов - Страница 40

In conventional mold fabrication techniques, hot pressing techniques are typically applied to the fabrication of shoe soles (56). After selecting the appropriate mold for the fabrication of a shoe sole, a mixture of a foaming agent is added and heated, and the sole is formed after the mold is cooled. Hence, the temperature control of the mold in the hot pressing process is an important controlling factor.

The heating of a shoe sole mold is performed via a hot plate, wherein the shoe sole mold is placed on a hot plate with a hot liquid tunneling through and the shoe sole mold is heated via heat conduction. However, relying upon the conduction method for heat conduction is time consuming. Furthermore, the surface of the mold used in hot pressing is closer to the hot plate, and that mold surface is heated faster than other areas of the mold, resulting in an overall uneven heating. In addition, the heat emitted from the hot plate is not absorbed solely by the neighboring regions of the hot pressed surface. Consequently, the power consumption is increased.

The current technology further includes directly incorporating a heating unit in the mold. However, such a mold necessitates a reconnection of the wirings of the hot plate when the mold is being replaced; hence, the mold replacement process becomes more complicated. Furthermore, incorporating a heating unit in the mold increases the fabrication cost and the removable heating pipelines also present safety issues (56).

So, a mold thermal controlling device for efficiently heating or cooling a mold was developed (56). Figure 1.5 is a schematic view illustrating a mold thermal controlling device and a mold.

The injection end 232 and the discharge end 234 pierce through the first temperature control layer, and the heated or cold liquid is injected through the injection end 232 and is discharged from the discharge end 234. Since the replacement of the mold 110 does not require any changes to the temperature control tunnel 230, deterioration of the temperature control tunnel 230 due to frequent changing is reduced, and safety and the replacement efficiency are improved.

In particular, the mold thermal controlling device includes a first trench, a first temperature control layer and at least a temperature control tunnel. The first temperature control layer includes a first temperature control face and the first temperature control layer forms a first temperature control trench forming the inner surface of a part of the first trench. The first temperature control trench is used for accommodating or containing a mold and is in contact with the mold through the first temperature control face. The temperature control tunnel is disposed in the first temperature control layer. A heated fluid or a cold fluid is injected into the temperature control tunnel. When the mold is placed in the first temperature control trench, the first temperature control face is positioned between the mold and the temperature control tunnel.

Figure 1.5 Mold thermal controlling device (56).

The mold thermal controlling device further includes a first surface having a first trench, and the opening of the first trench is positioned at the first surface. The cross-sectional area of the first trench tapers from the opening of the first trench along the first direction, and the mold is placed in or removed from the first trench along the first direction.

The mold thermal controlling device applies a pressure to the mold along the first direction. The surfaces of the mold that is in contact with the first temperature control layer protrudes and concaves along the first direction, and the cross section of the opening of the first trench tapers along the first direction. The mold is placed in or removed from the first trench along the first direction.

Since the mold thermal controlling device includes a temperature control tunnel that is formed with the temperature control layer, the temperature control tunnel can efficiently heat or cool the mold placed therein. Moreover, the mold used with the mold thermal controlling device can be easily replaced, and there are structures that may be included in or on the mold to assist the positioning of the mold, the gas discharge or to perform a grabbing action. Additionally, the mold thermal controlling device may be applied to an automated fabrication process. Since the hot press system of the disclosure includes the above mold thermal controlling device, which can provide heating or cooling with high efficiency, the hot press system of the disclosure can be broadly applied to various hot pressing processes (56).