The core of the piezoelectric valve drive consists of the piezoelectric ceramic stack and the vibrating diaphragm. Damage can lead to weak jetting or frequency deviation:

Fault Diagnosis

Check the drive waveform: Use an oscilloscope to verify whether the piezoelectric drive voltage reaches the rated value (typically 150‑200V). Waveform distortion indicates ceramic aging.

Listen to the jetting sound: A dull sound suggests a cracked vibrating diaphragm, while no sound may indicate an open circuit in the piezoelectric stack.

Test the jetting frequency: If the maximum frequency drops by >20% under rated voltage (e.g., from 800Hz to 600Hz), replacement is required.

Immediate Repair

Piezoelectric ceramic failure: Replace with the same model stack module, using a dedicated fixture to calibrate displacement (tolerance ±0.5 μm).

Vibrating diaphragm crack: Clean the valve chamber and replace the titanium alloy vibrating diaphragm (surface roughness < Ra 0.2 μm).

Drive circuit failure: Check whether the MOSFET is short‑circuited; after replacement, reprogram the drive waveform parameters.

Life Extension Strategies

Avoid dry jetting: Install a liquid‑level sensor to automatically stop jetting when the fluid surface is <2 mm below the nozzle.

Cooling protection: Activate forced air cooling when the valve body temperature exceeds 50 ℃ (adding a Peltier thermoelectric cooler is recommended).

Impact prevention: Maintain a jetting height ≥1mm to prevent the vibrating diaphragm from striking the substrate.

Bubbles in jet valves can cause interrupted spraying or jet trajectory deviation and require targeted handling:

Material Pretreatment

Vacuum degassing: Connect the adhesive barrel to a –90 kPa vacuum system. Degassing time should be adjusted based on viscosity (e.g.,

• Low viscosity (<500 cPs): 5 minutes
• High viscosity (>5,000 cPs): 40 minutes).

Constant-pressure supply: Use a gear pump for adhesive supply, keeping pressure fluctuation ≤ ±0.1 bar (for bubble‑sensitive adhesives, a degassing membrane module is recommended).

Valve Structure Optimization

Eddy‑current suppression design: Install a honeycomb flow guide (aperture 0.3 mm) at the adhesive chamber inlet to eliminate turbulent bubbles.

Hard‑sealing treatment: Replace fluoroelastomer seals with metal seals to reduce gas permeation (suitable for anaerobic adhesives).

Jetting Parameter Adjustment

Pre‑jet exhaust: Perform 50 high‑frequency dry‑jet cycles (1 kHz) each time the system is started.

Pulse‑width fine‑tuning: Increase the opening time (+5–10 μs) to allow bubbles to be carried out with the jet.

Viscosity‑temperature matching: For example, heating epoxy resin to 45 ℃ can reduce viscosity below 300 cPs, facilitating bubble escape.

If you still cannot effectively diagnose or resolve the problem, click the [Contact Support] button below, briefly describe your issue, and provide the equipment model and adhesive type. We will then customize a solution for you.