What methods can be used to reduce the vibration frequency of hot runners?

Three main factors must be addressed in order to lower the vibration frequency of hot runners: removing the vibration source, preventing resonance, and absorbing vibration. The following is a priority summary of common methods:

1. Reducing Source Vibration Excitation (Highest Priority Adjustment)

Adjust the injection molding machine's mold opening and closing speed to lessen the mold closing impact force and prevent high-frequency impact transmission during mold opening and closing. Reduce injection speed and holding pressure fluctuations to weaken the pulsating impact produced by melt injection, directly lowering the excitation frequency of fluid vibration.

Optimize runner structure design: Use periodic bifurcation structure design to minimize flow pulsation and the likelihood of vibration excitation at the flow level; increase the runner turning radius and decrease abrupt changes in cross-section to lessen turbulent disturbances in melt flow.

2. Modifying Natural Frequency to Steer Clear of Resonance Zones

Increase support and shorten span: To prevent vibration, add auxiliary support blocks to the manifold, shorten the unsupported span, enhance the hot runner system's overall stiffness, raise the natural frequency, and stay out of the excitation frequency range.

In order to alter the system's inherent frequency and prevent resonance amplification brought on by overlap with the excitation frequency, high-temperature resistant counterweights should be added to the manifold's non-working area.

Modifying pipe parameters: To improve system stiffness and natural frequency while avoiding the resonance range, suitably increase the pipe diameter and decrease the main pipe length for the main flow channel.

3. Increasing damping to absorb vibration energy: To block the vibration transmission path, absorb vibration energy, and directly attenuate the vibration amplitude, install high-temperature resistant damping pads (such as copper-based composite pads or high-temperature damping pads) between the manifold and the template.

To reduce the nozzle vibration amplitude and stop high-frequency nozzle vibration from spreading throughout the system, attach separate dampening fixing sleeves to the hot nozzles.

Reduce the specified vibration frequency in the system parameters directly for hot runners intended for active vibration, keeping it within a safe range below 30 Hz.