The automatic glue injection robot's negative pressure glue supply system fundamentally alters the gas behavior during glue flow by creating a vacuum environment, becoming a core technical means for suppressing bubble formation. This system establishes negative pressure during the glue delivery phase, allowing dissolved gases and tiny bubbles in the glue to rapidly expand and escape due to the pressure differential. This eliminates potential gas sources earlier than with normal pressure glue delivery. For example, epoxy resin glues are susceptible to air incorporation due to agitation or temperature fluctuations under normal pressure. The negative pressure system continuously draws a vacuum, reducing the glue's viscosity while accelerating gas release, physically blocking the bubble formation pathway.
The design logic of the negative pressure glue supply system is centered around "pressure control - gas separation - stable delivery." Its core components include a vacuum pump, a pressure sensor, and a sealed glue supply line. The vacuum level is dynamically adjusted by a PLC or industrial computer to ensure negative pressure throughout the glue's journey from the storage tank to the dispensing port. When the glue is delivered by a screw pump or gear pump, the negative pressure offsets the shear forces generated by the pump's operation, preventing air from being drawn in by mechanical agitation. The system's in-line degassing module also provides secondary glue treatment, gradually releasing residual gas through a multi-stage vacuum chamber to further reduce bubble content.
In practical applications, the effectiveness of a negative pressure glue supply system in suppressing bubbles is influenced by a synergistic effect of multiple factors. Vacuum level is a critical parameter: excessively high levels can cause glue volatilization or increase equipment load, while too low levels prevent thorough degassing. Typically, the electronic packaging industry requires a stable vacuum level between -0.08 MPa and -0.1 MPa to effectively remove bubbles while maintaining stable glue performance. Furthermore, the matching of glue viscosity and negative pressure is crucial. High-viscosity glues require the boost function of a screw pump to ensure stable flow under negative pressure. Low-viscosity glues require optimized piping design to prevent turbulence and air entrapment caused by excessively high flow rates.
From a process-adaptive perspective, negative pressure glue supply systems offer particular advantages for handling two-component glues. Two-component adhesives are prone to generating gases due to chemical reactions during the mixing process. A negative pressure environment can accelerate gas escape and prevent the formation of voids after curing. For example, in IGBT module potting, a negative pressure adhesive supply system, combined with a dynamic mixing valve, can extract reactive gases instantly during adhesive mixing, ensuring uniform filling of the power module with thermally conductive silicone, improving heat dissipation efficiency and insulation. For single-component adhesives, the negative pressure system reduces the adhesive's surface tension, minimizing dripping and stringing at the adhesive outlet, and indirectly reducing the risk of bubble adhesion.
In terms of efficiency and stability, the negative pressure adhesive supply system achieves continuous optimization of bubble suppression through automated control. The system's built-in pressure feedback mechanism adjusts the vacuum level in real time to compensate for pressure fluctuations caused by ambient temperature changes or adhesive depletion. For example, during continuous production, when the glue barrel level drops, the system automatically increases the vacuum pump power to maintain a stable negative pressure in the glue supply line. Furthermore, the sealed design minimizes contact between the adhesive and the outside air, reducing the likelihood of bubble formation caused by moisture or impurities, making it particularly suitable for medical and semiconductor industries with strict cleanliness requirements.
Long-term operational data shows that automated glue injection robots using a negative pressure glue supply system can reduce product bubble defect rates by over 90%. In chip underfill processes, negative pressure glue supply ensures that glue fully penetrates the tiny gaps between the chip and substrate, preventing thermal stress cracking caused by bubbles. In fiber-coupled packaging, vacuum potting with highly transparent glue reduces optical signal loss and enhances imaging clarity. These case studies demonstrate that negative pressure glue supply systems not only improve product quality but also lower overall costs by reducing rework and scrap.
As precision manufacturing progresses toward micron-level resolution, negative pressure glue supply systems are evolving towards higher precision and greater intelligence. For example, AI algorithms are being introduced to predict bubble generation probability and dynamically adjust vacuum levels and glue supply parameters; nanoscale dispensing technology is being used to adapt to chip-scale packaging requirements. In the future, negative pressure glue supply systems will become standard features of automated glue injection robots, providing a more stable and efficient bubble suppression solution for high-end manufacturing.
