| 摘要 |
<p>An injection molding apparatus is provided for controlling the rate of material flow into a mold cavity or plurality of mold cavities during an injection cycle. The apparatus is, for example, a hot runner system for injecting plastic melt. A valve pin is provided for controlling the flow of material away from the gate. A gap is formed between the surface of the valve pin and the surface of the material flow bore away from the gate. Control of material flow is achieved by displacing the valve pin and thereby adjusting the size of the gap. A control system is provided that compares a sensed condition indicative of the rate of material flow into the mold cavity to a target profile of the sensed condition, and adjusts the valve pin during the injection cycle to mirror the target profile.</p> |
