| 摘要 |
<p>This invention relates to an improved core ring gated injection molding system. The valve pin has a tip portion which joins a larger diameter stem portion at a tapered shoulder and extends through the cavity into the mold platen on the other side. The tip portion of the valve pin is substantially smaller in diameter than the gate through the cavity plate, thus providing for the flow of melt through the gate around it when the valve pin is in the retracted open position. In the forward closed position, the tapered shoulder seats in the gate to provide a seal. By providing for operation in reverse directions to previous core ring gated systems, this increases cooling to the mold platen in the closed position and decreases it in the open position.</p> |
