Servo Valves for Rubber Injection Molding
The hydraulic controls on rubber injection molding presses experience high demands due to the high injection pressures, long cure times, and clamp force. Domin servo proportional valves are designed to give these presses fast response and fine control resolution, so the injection and clamp behavior is predictable and precise for the entire cure cycle.
The Challenges of Control in Rubber Molding
Rubber injection molding uses viscous, often abrasive compounds. The press injects that material into heated cavities, then holds steady clamp force and pressure while the rubber cures. The challenge comes in maintaining repeatable pressure and clamp behavior from shot to shot under high pressure and long dwell times.
Servo Valves for Consistent Clamping
There are two jobs that a valve must perform during rubber injection molding. First, it must control the injection of the material into the mold. The valve must perform accurately and repeatedly during this phase. Second, it must hold a clamp force while the rubber cures. Here, the valve must perform steadily and have proper stability. For more information about clamp force in injection molding, read our article here.
This control differs from plastic injection molding because the material, rubber, within the mold takes longer to cure than plastic does to set. Because it takes longer to properly form, valves in these scenarios can stand to have slightly more lenient response rates, but benefit from being more sturdy.
Our Recommended Valves
The P6 Pro is our primary recommendation for most rubber injection molding applications, as it is a proportional valve developed for precise control in small to mid-sized industrial systems. Though it does not have response rates as fast as its S Series counterpart, this valve is perfectly suited for applications where the control requirements are not as dynamic. The P6 Pro is a robust, cost-effective solution.
On larger rubber presses, or where axes might need higher flow and more coordinated control, it may be beneficial to pair a P6 valve with a higher capacity P Series valve, such as the P10, or even an S Series valve for more dynamic, more precise, faster control. In fact, a lot of presses feature both the S series and the P series, differentiating between the needs in various parts of the press. Shot-to-shot repeatability, for example, is a dynamic task that benefits from faster response times that the S Series excels at. To go more in-depth, read our article here.