The screw tip is a non-return valve that allows molten polymer flow in one direction and shuts off in the other direction, a critical component in injection molding processes. We manufacture a wide range of screw tips for all makes of injection molding machines. The most common screw tip sets are free flow 3-piece or 4-piece design check ring valves. In general, screw tip designs fall into one of the following categories: sliding check ring, locking check ring, PVC smear tips, ball check valves, etc. A good screw tip must provide positive shut off and create a consistent cushion while not restricting flow during recovery. The best screw tips also inhibit degradation and resist abrasion and corrosion. How well your screw tips meet those requirements depends on the mechanics of the tip’s seal, its internal flow geometry, and its construction materials.