PUR type Piezo valve for Hot melt glue dispensing on Middle frame of Mobile phone/mini PAD

In mid-frame applications, hot melt adhesive is widely used to bond metal, glass, or plastic components while offering excellent shock absorption and waterproof sealing. Piezoelectric jet valves offer a precise and efficient solution for dispensing hot melt adhesives (HMA) in mobile phone and mini pad mid-frame assembly. With their high-speed, non-contact jetting technology, these valves enable accurate adhesive placement on narrow and complex frame structures, ensuring strong bonding without contamination or overflow. This is critical in consumer electronics manufacturing, where slim profiles and tight tolerances demand micron-level dispensing precision.

Piezo jet valves handle low- to medium-viscosity hot melt formulations with controlled shot volume and dot size, ensuring consistent performance across mass production lines. Equipped with Glue barrel heating module and flow channel heating module, piezo valves maintain adhesive viscosity and prevent clogging during prolonged use. The modular design allows quick flow channel replacement and easy maintenance, reducing downtime and improving throughput. In addition, the use of corrosion- and heat-resistant materials ensures durability when operating under high temperatures and demanding adhesive chemistries.

Core Advantages

1. Micro-precision control
2. Non-contact high-speed injection
3. Good temperature control:

There is a special glue barrel heating module, 30CC/50CC are available; the flow channel heating module ensures the nozzle temperature to prevent clogging
4. Heat-resistant and wear-resistant structural design

Main appliaction

• Gluing of mobile phone middle frame: the joint surface between middle frame and back cover, display module, battery cover, etc.
• Gluing of Mini Pad middle frame: the middle frame is fixed with front and rear shells, display screen or internal structural parts

Technical parameters

FAQ

Q1: How does the piezoelectric valve solve the clogging problem of hot melt adhesive under high temperature?
A1: Mingseal piezoelectric valve has a constant temperature design, and the valve body integrates a heating module (usually 80~200℃) to keep the glue molten.
Quick disassembly structure: supports thermal disassembly cleaning, or ultrasonic cleaning of flow channel residues.

Q2: Can high-viscosity hot melt adhesive (such as EVA-based) be sprayed stably? How to optimize?
A2: Viscosity-temperature matching: reduce viscosity by heating (need glue temperature resistance support).
Valve parameter tuning: adjust the drive voltage waveform and injection frequency to reduce the influence of shear force.

Q3: Can the injection accuracy and speed of the piezoelectric valve meet the needs of high-speed production lines?
A3: Accuracy: can reach 0.5nL minimum accuracy, repeatability accuracy ±2%.
Speed: The maximum injection frequency of a single valve is 1kHz, which is suitable for high-speed assembly lines (such as electronic SMT mounting).
Multi-valve collaboration: multiple sets of piezoelectric valves can be used in parallel to improve UPH.

Q4: What is the life and maintenance cost of the piezoelectric valve?
A4: Lifespan: Piezoelectric stack, typical lifespan is more than 800 million times.
Maintenance: Only the sealing ring (high temperature resistant fluororubber) needs to be replaced regularly, and the impact needle nozzle needs to be replaced 300 million times on average.

Q5: How to be compatible with hot melt adhesives of different models/colors? Is it necessary to stop the machine for cleaning when switching?
A5: Quick glue change system: Cleaning is required when changing glue. The piezoelectric valve flow channel supports quick replacement. It is recommended to use a spare flow channel for quick replacement.

About Mingseal

Founded in 2008, Changzhou Mingseal Robot Technology Co., Ltd. is a technology-driven manufacturer of high-end equipment, specializing in connection, assembly, inspection systems, and key components for advanced semiconductor packaging and precision electronics. Our solutions are widely adopted by leading customers in sectors such as semiconductor packaging, consumer electronics, and automotive electronics. With a strong presence across Asia and the Americas, we deliver reliable support and innovation globally.

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