How to determine if the vibration frequency of a hot runner is too high?

Three stages can be used to determine this step-by-step: professional measurement, simple inspection, and production phenomena. The approach is straightforward and simple to use:

1. Initial assessment based on production phenomena (rapid identification, no tools needed)

In essence, it can be concluded that the vibration frequency is excessively high if two or more of the following occur at the same time:

Product level: Significant variations in the size of continually manufactured goods, frequent surface stains or flow marks, inconsistent products in multi-cavity molds, and an abrupt rise in the defect rate;

Equipment level: Heating coil solder joint fracture, frequent hot runner screw loosening, sealing leakage in a brief amount of time, and noticeable abnormal noises during production;

Sensor level: Significant variations in temperature and pressure sensor output data, frequent reading jumps, zero-point drift, and the incapacity to deliver steady measurement signals.

2. Low-Cost Verification via Basic Tool-Assisted Testing

Once production has steadied and the injection molding machine has been shut down due to a power outage (make sure the equipment has stopped entirely and pay attention to safety):

Put your hand close to the hot runner on the outside of the mold. The vibration amplitude/frequency is excessive if you can detect a persistent, tingling vibration or even a minor shaking of the mold with the unaided eye.

In the vicinity of the hot runner installation site, use a stethoscope. You can also conclude that the vibration is abnormal if you hear clear high-frequency noise or erratic odd sounds rather of a consistent and steady functioning sound.

3. Accurate Measurement Using Expert Equipment (Verifying the Conclusion)

A professional vibration meter can be used if an exact measurement is needed:

Measure the vibration frequency during stable production by attaching the vibration meter to the exterior of the hot runner manifold or mold plate. The vibration frequency is deemed excessively high if the measurement result is greater than 30 Hz.