What causes air bubbles to form in silicone tubing during production?

Bubble formation typically traces back to raw materials, process control, or tooling. On the materials side, impurities or residual moisture in fillers such as fumed silica can release gas during the high-temperature cure cycle, leaving voids in the tube wall. Insufficient mixing during compounding traps air in the stock, while poorly controlled dump temperatures and mix times allow volatiles to remain in the compound before extrusion. Inadequate cure time or temperature is another common cause: when crosslinking is incomplete, dissolved gases that would otherwise escape precipitate as bubbles and become locked in the wall as the material sets. On the tooling side, poorly positioned vents in compression molds prevent the cavity from purging air during closure. In platinum-addition cure systems specifically, a side reaction between hydrogen-bearing silicone oils and hydroxyl-functional components can generate hydrogen gas if the formulation is not properly balanced — a factor that must be addressed at the compound design stage. Ruixiang controls bubble risk through incoming raw material inspection, standardized compounding parameters, and in-line dimensional monitoring, with visual inspection as part of the outgoing quality check.

For product specifications, technical data sheets, or sample requests, contact the Ruixiang team: olivia@dgruixiang.com  |  www.medicalsiliconetube.com