Complete Guide to 9 Glue Types for Dispensing Machines: Essential Tips & Equipment Selection

Did you know that improper glue dispensing can waste up to 30% of materials in electronics manufacturing? Whether you’re working with fast-curing cyanoacrylate or temperature-sensitive epoxy, choosing the right dispensing setup is critical for precision and efficiency. This guide breaks down key techniques for 9 common adhesive types, simplified for engineers and operators.

Instant Adhesives (Cyanoacrylate)

Common uses: Bonding plastics, rubber, and metals in electronics and automotive assembly.

Key Tips:

• Syringe Selection: Use Teflon-lined stainless steel barrels to resist clogging (common with fast-curing adhesives).
• Needle Choice:
  • Tapered needles for high-viscosity glue
  • Polypropylene (PP) needles for flexible dispensing
• Anti-Drip Fix: Enable vacuum-assisted retraction to prevent leaks.

Pro Tip: Add a desiccant to storage containers to slow premature curing.

UV-Curing Adhesives

Common uses: Optical lens assembly, medical device sealing.

Key Tips:

• Light Protection: Use amber-colored syringes and opaque tubing to block UV rays (prevents curing in the dispenser).
• Temperature Control: Maintain glue at 23–25°C using heated hoses. Cold glue increases viscosity, causing uneven flow.
• Curing Check: Apply 365–405nm UV light at ≥2000mJ/cm² intensity. Use a radiometer to verify curing energy.

Epoxy Resins

Common uses: Structural bonding, potting electronics.

Key Tips:

• Bubble Prevention: Use single-component syringes with tight seals. Degas epoxy in a vacuum chamber before dispensing.
• Storage: Refrigerate at 0–5°C. Thaw for 30 minutes before use.
• Pressure Settings:
  • Low viscosity: 10–20 psi
  • High viscosity: 30–50 psi

Underfill Adhesives (for SMT/BGA)

Common uses: Chip packaging in smartphones, CPUs.

Key Tips:

• Jet vs. Needle Dispensing:
  • Jet dispensing for high-speed, non-contact applications
  • Needle dispensing for precise underfill flow control
• Needle Size: Use 25–30G needles (0.26–0.15mm) for micro-scale circuits.

Conductive Adhesives & Solder Paste

Common uses: EMI shielding, circuit board repairs.

Key Tips:

• Dispensing Method: Auger valves for pastes with metal fillers (e.g., silver epoxy).
• Resistance Check: Aim for <0.001 Ω·cm. Stir adhesive before use to prevent filler settling.

Conformal Coatings (Waterproofing)

Common uses: Protecting PCBs in harsh environments.

Key Tips:

• Spray Valve Setup: Adjust atomization pressure to 10–15 psi for even coating.
• Layer Thickness:
  • Acrylic coatings: 25–75µm
  • Silicone coatings: 50–200µm

Two-Part Adhesives (Epoxy/Acrylic)

Common uses: Aerospace composites, automotive parts.

Key Tips:

• Mixing Ratio: Use dual-chamber syringes with static mixers (e.g., 16-channel spiral tubes).
• Clog Alert: Monitor pressure spikes (>15% increase = mixer blockage).

Silicone & Lubricants

Common uses: Gasket sealing, industrial machinery.

Key Tips:

• Screw Valve Advantage: Handles high-viscosity materials (up to 500,000 cP).
• Flow Consistency: Preheat material to 40°C for stable dispensing.

Anaerobic Adhesives

Common uses: Threadlocking, retaining bearings.

Key Tips:

• Oxygen Sensitivity: Store in air-permeable containers.
• Curing Time: Accelerate with metal-ion activators for faster bonding.

Glossary of Key Terms

• Viscosity: A fluid’s resistance to flow (measured in centipoise, cP).
• Static Mixer: A tube with spiral channels that blends two adhesive components.
• Degassing: Removing air bubbles from adhesives using vacuum pressure.