As technology matures, traditional dispensing methods are increasingly being replaced by advanced processes. Jet dispensing, with its shorter response time, higher repeatable accuracy, and finer control over droplet volume, has become the choice for more and more industries and enterprises.

Simultaneously, the growing diversity and complexity of adhesives and their processes are placing increasingly stringent demands on valve performance. 

As an expert in high-precision jet dispensing applications, Quark Research Institute possesses extensive process application experience. Today, based on past cases, we discuss the dispensing challenges and solutions for different types of adhesives.

Low-Viscosity / High-Fluidity Adhesives

Characteristics: Low viscosity (near water-like), high fluidity.
Examples: Underfill, low-viscosity UV/Acrylic adhesives, fluorinated liquids, rosin-based flux, etc.

Process Challenges

• High fluidity can lead to splattering, bubbles, and satellite droplets.

• Difficulty forming stable droplets during high-speed jetting, prone to break-off.

• Challenge in achieving micro-volume control.

Quark Application

• Possesses splatter and bubble suppression capabilities far exceeding industry standards, enabling continuous dispensing without bubbles or splatter.

• Superior micro-volume control, with a minimum droplet volume as low as 1.0 nl, meeting a wider range of scenario needs.

| Underfill Case : One Week of Continuous Production with Scatter Rate <0.05%

| UV Adhesive Case: Uniform and Precise Continuous Dispensing, Bubble-Free with No Overflow

Low-viscosity adhesives represent a critical application scenario for piezoelectric jet valves. Leveraging superior scatter control and bubble suppression capabilities, Quark continues to expand the boundaries of applicable processes.

Medium-Viscosity / Filled Adhesives
Adhesive Characteristics: Contains metal particles (Ag, Cu, Sn, etc.) or non-metallic fillers
Examples: Conductive silver adhesive, liquid metal, filled potting/structural adhesives
Process Challenges:

• Filler settlement leads to inconsistent composition

• Nozzle clogging in micro-fluid control applications

• Filler abrasion reduces valve core service life
  Quark Solutions:

• Advanced valve control logic ensures stable and consistent dispensing

• Wear-resistant materials support over 1 billion dispensing cycles, meeting long-life requirements

| Silver Adhesive Case: Uniform dispensing lines with adhesive thickness <40μm, no clogging or stringing

From dots to lines, Quark piezoelectric valves meet complex process demands while delivering high repeatability and consistency over extended production runs.

High-Viscosity Bonding Adhesives
Adhesive Characteristics: High viscosity, poor flowability
Examples: Hot melt adhesives, epoxy encapsulants
Process Challenges:

• High viscosity filamenting and bubbles

• Heating to improve flowability may cause seepage or leakage

• High equipment cleaning and maintenance frequency required
  Quark Solutions:

• Enhanced bubble suppression enables continuous production without bubbles

• Integrated sealing in the heating module effectively prevents seepage and leakage

• Minimum dispensing width <0.3mm, adaptable to various process scenarios

| Hot Melt Adhesive Case: Continuous dispensing without waves, breaks, or bubbles

For high-viscosity bonding adhesives, Quark achieves higher dispensing accuracy through optimized configurations and parameters, while automated adhesive purging and wiping functions support long-term operation.

Solder Paste
Fluid Characteristics: Paste-like at room temperature, thixotropic
Process Challenges:

• High difficulty in precise micro-control

• Prone to stacking and clogging during prolonged production

• Demands dust-free and temperature-stable environments
  Quark Solutions:

• Specifically designed for micro-soldering applications with strong anti-clogging performance for stable long-term dispensing

• Higher dispensing accuracy: minimum line width <0.25mm, minimum dot diameter 0.2mm, meeting most process requirements

| Solder Paste Dispensing Case: Continuous dispensing for over 3 hours without clogging

Quark offers a mature series of solder paste valves compatible with #6, #7, and finer pastes, ensuring stable performance and clog-free operation for enhanced efficiency and precision.

Fast-/Easy-Curing Adhesives
Adhesive Characteristics: Cures easily under environmental influences (temperature/gas/light)
Examples: Fast-curing acrylic adhesives, UV-curable adhesives, thermosetting adhesives (fast-curing types)
Process Challenges:

• Requires uniform and stable working temperature

• Adhesive curing can easily cause clogging

• Residual adhesive Curing of residual adhesive can easily clog the valve body, complicating maintenance
  Quark Solutions:

• Integrated heating module with ±2°C temperature control ensures a stable dispensing environment

• Quick-disassembly design facilitates easy cleaning for frequent maintenance

| Thermosetting Adhesive Case: Stable precision during continuous operation with no clogging

For such adhesives, Quark supports optional quick-disassembly valve series and flexible integration of heating modules to meet complex process needs in one stop.

High-Thixotropy / Viscoelastic Adhesives
Adhesive Characteristics: High thixotropy (thickens at rest, thins under shear)
Examples: LED silicone adhesives (encapsulation/lens), Tuffy adhesives, and some structural/potting adhesives
Process Challenges:

• Initial dispensing may cause oversized droplets or failure to dispense

• Inconsistent performance over long processing periods

• Filamenting or retraction may occur at cutoff
  Quark Solutions:

• Higher dispensing accuracy: volume error <±1%, dot diameter range <50μm, ensuring consistent dot size

• Optimized valve cooling system ensures stable dispensing quality

| Silicone Adhesive Case: Bubble-free with minimal scatter, uniform and stable continuous dispensing

To meet advanced process demands, Quark piezoelectric valves enable precise fluid control, ensuring consistency in dispensing shape and size.

Precision in the Micro, Mastery in the Macro
Today, Quark piezoelectric valves already meet a wide range of process requirements with superior dispensing and repeatability accuracy. Our fluid control performance helps more enterprises improve yield and efficiency.

What process challenges have you encountered in dispensing? Feel free to share or inquire in the comments!