Extrusion occurs when high pressure forces seal material into the clearance gap. Soft seals like rubber are more susceptible. Backup rings, made from harder materials like PTFE or nylon, prevent extrusion. Increasing seal hardness or reducing clearance gaps also helps. In ultra-high-pressure systems above 700 bar, specialized seal designs with multiple backup rings are essential for p... https://globalsealstech.com/hydraulic-seals/