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Plastic Molding Apparatus

IP.com Disclosure Number: IPCOM000081664D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Delaney, A: AUTHOR [+2]

Abstract

In the apparatus of Fig. 1, two thin flexible parts or molds 2 and 3 the entrance for filling the cavity 4.) Fig. 2 is a perspective view of such a part formed in cavity 4. Molds 2 and 3 are supported by conventional elements 5 and 6. Supports 5 and 6 are shaped to operate with a variety of molds without regard to particular features of a mold shape and, as Fig. 1 shows, mold parts 2 and 3 may occupy only a small portion of the volume of the supports.

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Plastic Molding Apparatus

In the apparatus of Fig. 1, two thin flexible parts or molds 2 and 3 the entrance for filling the cavity 4.) Fig. 2 is a perspective view of such a part formed in cavity 4. Molds 2 and 3 are supported by conventional elements 5 and
6. Supports 5 and 6 are shaped to operate with a variety of molds without regard to particular features of a mold shape and, as Fig. 1 shows, mold parts 2 and 3 may occupy only a small portion of the volume of the supports.

During various stages of the molding operation, hot or cold oil is pumped into the support to heat or cool the mold. Oil inlets 7 and 8 and oil outlets 9 and 10 direct this flow of oil into the space between molds 2 and 3 and diaphragms 11 and 12. The diaphragms have holes 13 that equalize the pressure. The diaphragms 11 and 12 fit closely to mold parts 2 and 3, and thereby limit the amount of heated or cooled oil that would otherwise be required.

Each mold part 2 and 3 has a strain gage 15 that produces electrical signals according to the deflection of the flexible molds, as plastic is injected into the mold cavity 4. These signals are used to vary the oil pressure to the value required to support mold parts 2 and 3. For example, a pump may supply oil at a substantially uniform rate at inlets 7 and 8 and a valve at outlets 9 and 10 may be adjusted to control the oil pressure.

When molds of this general type are used for molded foam plastic parts, the parts commonly have a poor surface that...