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Molding Technique

IP.com Disclosure Number: IPCOM000095070D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Mayron, H: AUTHOR [+2]

Abstract

Intricate flat plastic articles are moldable by a two-step technique which prevents buildup of internal stresses.

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Molding Technique

Intricate flat plastic articles are moldable by a two-step technique which prevents buildup of internal stresses.

The article is injection molded in an intricate pattern mold, removed from the intricate mold as soon as it has set sufficiently to retain the pattern, and placed between heated flat platens for the final setting and curing. Internal stresses in the article resulting from the intricate pattern molding are relieved harmlessly during the final setting and curing step.

The memory support plane shown in the step 2 drawing requires a large number of relatively small precision holes which line up when several of the planes are stacked. The planes also must be flat and free of internal stresses which might cause bulging. Achievement of these requirements is difficult because of the intricacy of the pattern.

The mold for the memory support plane includes a large number of tiny projections which cause the holes in the memory support plane. Cylindrical projections, which might seem appropriate since they produce round holes, require assembly techniques to produce the mold. A mold having rectangular projections is significantly less costly to produce than a mold having cylindrical projections. The article works just as well. The rectangular projections are made by relatively simple milling techniques.

Gases accompanying the plastic molding process, including the air in the mold cavity, present a problem in molding a small article of intricate p...