With years of experience in the dispensing industry, it is clear that mixing tubes and AB cartridges play a crucial role in dual-component adhesive applications. They are not just consumables—they directly impact mixing uniformity and dispensing stability. From a fluid dynamics perspective, proper design is essential for stable dispensing processes.
When dual-component adhesives enter the mixing tube, they are subjected to shear and splitting by spiral blades or square partitions. Each spiral element divides and recombines the adhesive, repeatedly splitting and merging the flow until a uniform mixture is achieved. The more spiral elements, the better the mixing, but resistance also increases. For instance, in smartphone camera module assembly, insufficient spiral elements in low-viscosity fast-curing epoxy may cause local uneven curing. In automotive lighting sealing, high-viscosity PU adhesives require more spiral elements to ensure complete mixing and avoid leaks.
The tube diameter directly affects flow rate and mixing efficiency. Large diameters support high flow rates but provide less shear, potentially causing incomplete mixing. Small diameters offer thorough mixing but increase resistance, which can stall the piston. In medical device assembly, small-diameter tubes ensure precise dispensing; in motor potting, large diameters maintain high throughput. Poorly designed diameters may also create dead zones, where high-viscosity adhesives remain and prematurely cure, affecting stability. Using smooth transitions in the tube design helps reduce residue and improve continuous operation efficiency.
Spiral structure types are also critical for mixing efficiency. Single-spiral tubes suit low-viscosity adhesives with low resistance and cost, but for high-viscosity or fast-curing adhesives, single spirals may leave unblended streaks. Double-spiral designs significantly enhance uniformity. Square or multi-grid structures further improve flow splitting but increase resistance, requiring stronger dispensing force; otherwise, piston movement may become unstable or fail.
For high-viscosity adhesives, AB cartridges must have thicker walls and high-strength plastics (e.g., modified PP or PA) to withstand pressure while allowing visual monitoring of adhesive volume. Pistons typically use silicone pads with O-rings to prevent leakage and reduce friction. Poor sealing can lead to backflow or piston slip, causing unstable dispensing. Interfaces endure significant stress; high-quality designs include reinforced or metal-reinforced sections, tested at 2–3 times working pressure to ensure safety and reliability.
In summary, the design of mixing tubes and AB cartridges directly determines adhesive mixing quality and dispensing stability. Choosing the right tube diameter, spiral structure, and cartridge design is key to maximizing dual-component adhesive performance. For high-viscosity or fast-curing adhesives, careful design and selection are especially critical. Experience shows that a well-chosen mixing tube and cartridge can solve most issues with uneven dispensing and unstable processes.