How to Repair Excessive Hot Runner Vibration?

There are several steps involved in fixing excessive hot runner vibration, ranging from straightforward to intricate, from troubleshooting to full resolution. Repair techniques that are easily implemented relate to different causes:

1. Start by fixing the most frequent problem, loose installation, which may be fixed in a day after disassembly:

Remove any remaining glue and contaminants from the mounting surface, loosen all manifold connecting screws, and adjust the mounting surface's levelness;

To remove connection gaps, tighten the screws diagonally and uniformly in stages in accordance with the manufacturer's recommended torque (tighten in two to three stages to avoid overtightening at once);

Examine the hot nozzles' and manifold's sealing positions, replace any old or distorted gaskets, realign and tighten, and fix any gap wobble.

2. Modify the process parameters (verification may be done in a matter of hours; machine disassembly is not necessary):

Lower injection speed by 15% to 30%, smoothly adjust holding pressure to lessen the influence of melt pulsation, and lessen source vibration intensity;

To lessen the impact force of the mold closing and prevent the transfer of external vibrations, lower the injection molding machine's mold opening and closing speed;

To prevent going beyond the permitted range for active vibration hot runner systems, immediately reduce the set frequency to less than 25 Hz.

3. Resonance/Design Defect Repair and Structural Optimization (finished in 1-2 days)

Excessive Manifold Span and Inadequate Stiffness: To reduce the unsupported span, increase system stiffness, and prevent resonance, place a high-temperature resistant support block in the center of the manifold.

Lack of Vibration Damping Design: Use stainless steel vibration damping sleeves on the hot nozzles to reduce nozzle vibration amplitude; place copper-based, high-temperature resistant damping pads between the manifold and the mold plate to prevent vibration transmission and absorb vibration energy.

Runner Design Defects: Smooth the transition section abruptly, decrease melt turbulence disturbance, lessen the vibration source, and enhance the runner turning radius by grinding the inner wall of the runner.

4. Replace Aging and Damaged Components: Replace worn-out and distorted hot nozzles and manifolds; rectify distorted mounting reference surfaces to address dynamic imbalance vibrations brought on by component deformation; modify the clearance of the injection molding machine's clamping mechanism, adjust the clamping force, and remove the impact of the machine's own yaw vibration on the hot runner.