| 摘要 |
<p>A process and apparatus for injection molding and a plastic article having a hollow rib portion (72) is formed utilizing a spill cavity (73). The process includes the steps of sequentially injecting fluent plastic and gas into a mold cavity having a space defining at least one wall portion of the article and a channel (66) defining a rib portion (72) of the article. A quantity of fluent plastic is initially injected to substantially fill the mold cavity. A charge of pressurized gas is then injected into the channel (66) of the mold cavity to displace a portion of the still fluent plastic into the spill cavity (73) which is flow coupled to the channel (66). Preferably, the thickness of the rib portion (72) in cross section is at least twice as large as the thickness of the wall portion in cross section along the entire length of the rib portion (72). Also, preferably, the channel (66) is tapered along its length. The rib portion may be either internal or external to the article.</p> |
