What Is a Runner Chuck?
A runner chuck is a chuck that grips the runner and removes the molded product from an injection molding machine. Molten resin, injected from the nozzle of an injection molding machine, is fed through a thick passage in the mold called a sprue, through a narrow passage called a runner, and finally through a place called a gate to the molding section.
Normally, a runner chuck is used to grip the runner and remove the molded product. However, it can also be used to chuck the molded product itself or the sprue.
Uses of Runner Chucks
Runner chucks are commonly used in injection molding machines where robots automate the removal of molded products. To facilitate this automation, several slide rails are combined, allowing the runner chucks to move along these rails.
Typically, a runner chuck clamps a runner between two claw-shaped metal fittings. It operates either electrically or pneumatically. Chucks with sensors on the jaws are generally used to monitor operation and facilitate the transition to subsequent steps.
Features of Runner Chucks
The method of removing molded products from a mold depends on the shape of the gate, the entry point to the molded product in the mold. In the direct gate method, where the sprue is directly connected to the gate at the center of the molded product without a runner, the molded product itself or the sprue is chucked. This method leaves large gate marks, necessitating post-gate-cutting finishing.
When the gate is connected to the side of the molded product via a runner, use runner chucks or chuck the sprue. Gate marks remain on the molded product, requiring finishing after gate cutting.
In the submarine gate method, where a tunnel-shaped gate is provided at the end of the runner, both the molded product and the runner are chucked. The gate is automatically cut when the mold opens, eliminating the need for post-molding processing.
In the pin gate method, which involves using three molds to separate the molded product from the runner, the molded product is chucked, and runner chucking may not be necessary. The runner and sprue, including the pin gate, are separated from the mold at the first mold split, and the molded product is removed in the subsequent split operation. The gates are automatically cut with the mold split, so post-molding gate cutting is not required.