How Servo Valves Control Clamping Force

In hydraulic systems, servo valves build, hold, and release clamp pressure based on feedback from the pressure transducers located on the clamp cylinder. A valve with high position accuracy combined with low hysteresis means precise movement in both directions. This leads to high product quality, repeatability, and reduced scrap rates.

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The Importance of Accurate Clamping in Injection Molding

Applications like injection molding require exceptional clamping control. Under clamping can result in flash defects and over clamping can create mechanical stress on the tie bars and tooling. Repeatable clamping force is also important, so that molds come out uniform and consistent.

Why Servo Valves are the Right Approach

Low hysteresis: Domin valves give the same output for a given signal, allowing for precise and repeatable positioning of the spool. This is critical for consistent clamping force, especially for multiple cycles.
Fast dynamic response: The combination of brushless DC motors, magnetic hall-effect sensors, and slim onboard electronics contribute to Domin’s extremely fast step response. This allows for stable clamping tonnage in injection molding.
Durability: Domin servo valves do not contain a pilot stage or tiny orifices that require high pressure seals. Therefore, the valve is highly resistant to contamination and reduces the most common failure modes.

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FAQ about Clamping Force Control

Excess tonnage stresses the tie bars, platens, and tooling. Over time this accelerates wear, distorts the mold, and can restrict venting.

If the clamping force is lower than the pressure pushing the mold open during injection, the mold halves separate slightly and melt escapes at the parting line. That escaped material solidifies as flash, which either adds a trimming step or scraps the part.

Domin servo valves respond in under 3.5 ms. That speed lets clamping pressure settle before injection begins and lets the valve correct disturbances while the mold is under load.

On large‑tonnage presses, this fast, precise control is critical to maintaining consistent clamp force across multi‑cavity molds and long production runs.

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