How To Solve Stringing in Dispensing Machines?

Imagine this: on a precision electronic assembly line, the dispensing nozzle moves smoothly, yet a hair-thin glue filament trails behind - this is the dreaded "stringing" phenomenon. It not only affects product appearance but may also cause short circuits, bonding failures, or even wholesale product rejection. For modern manufacturing that pursues "zero defects," stringing is an invisible threat that quietly erodes productivity and quality. Although common in dispensing processes, stringing is not unsolvable - by tackling issues in equipment, materials, and process parameters, the problem can be effectively eliminated.

Root Cause: Why Does Stringing Occur and How Do We Fix It?

Stringing occurs when the adhesive fails to separate cleanly during shut-off, forming fibrous residues. Multiple factors contribute to this, and the correct solution requires precise root-cause targeting:

1. Adhesive Characteristics & Environmental Control

Viscosity, rheology, and ambient temperature/humidity directly influence stringing tendency. High-viscosity adhesives (e.g., epoxy) are more prone to stringing due to strong cohesion. Preheating the adhesive or optimizing environmental conditions can significantly reduce stringing.

OKATA's equipment integrates an intelligent temperature-control module that dynamically stabilizes adhesive properties, suppressing stringing at the source.

2. Precise Control of Dispensing Parameters

Dispensing speed, pressure, and valve shut-off delay are critical. Excessive speed or improper timing causes glue to be stretched into a filament. Using a high-response piezo valve or screw valve with closed-loop control enables millisecond-level shut-off to eliminate residual glue.

OKATA dispensers feature adaptive pressure regulation that automatically optimizes parameters based on adhesive characteristics to ensure clean droplets.

3. Nozzle Design & Maintenance

Nozzle orifice size, surface finish, and wear condition affect stringing. Small orifices suit precision dispensing but may increase adhesion if rough or contaminated. Regular cleaning and replacement, and adopting low-surface-energy materials (e.g., PTFE coating), greatly reduce buildup.

OKATA's machines come with anti-stringing nozzles featuring specialized flow-path geometry to minimize residue.

Stringing Control: A System-Level Optimization, Not Just Shut-off

Eliminating stringing improves not only appearance but also overall manufacturing integrity:

Ensure High Yield and Consistency

In chip packaging and micro-sensor dispensing, stringing may cause shorts or signal interference. Through precision control, OKATA keeps stringing occurrence extremely low, enabling 99% process yield.

Boost Efficiency & Lower Costs

Stringing leads to rework and adhesive waste. With real-time monitoring and adaptive adjustment, OKATA systems reduce manual intervention, raise line efficiency by over 20%, and cut adhesive consumption.

Adapt to Diverse Adhesive Types

From UV glue to silicone, each adhesive behaves differently. OKATA's extensive process database ensures fast matching of material parameters to application requirements.

High-Risk Scenarios & Countermeasures

Semiconductor Packaging: Stringing may damage microcircuits. High-pressure jet valves enable non-contact dispensing, eliminating stringing entirely.

Consumer Electronics: In display bonding, stringing affects frame sealing. OKATA optimizes motion paths and shut-off algorithms to deliver clean, uniform bead lines.

Medical Devices: Implantable devices require extremely clean dispensing - stringing may introduce contaminants. OKATA's sterile-grade dispensing system ensures contamination-free operation.

Automotive Electronics: In ECU potting, stringing creates uneven coating. Closed-loop pressure feedback stabilizes performance despite adhesive fluctuations.

Why OKATA Technology Excels at Solving Stringing

OKATA integrates multiple patented anti-stringing technologies:

Intelligent Shut-off Algorithm: Predicts adhesive rebound and cuts off before stringing forms.

Multi-sensor Fusion: Continuously monitors adhesive condition and automatically adjusts dispensing parameters.

Modular Design: Enables quick swap of valves/nozzles to adapt to various adhesives and processes.

Customers consistently report outstanding performance when using OKATA dispensers with high-viscosity adhesives. The localized engineering service team also provides on-site process tuning to solve issues immediately.

Conclusion

Stringing may appear minor, but it impacts the entire manufacturing chain. By understanding adhesive characteristics, optimizing equipment parameters, and leveraging advanced technologies, the issue can be fully resolved.
As an industry leader, OKATA Technology continues to deliver reliable, high-precision anti-stringing solutions backed by strong technical expertise. Choosing the right partner ensures you stay ahead in the "micron-level battlefield" of modern manufacturing.