{"product_id":"plastic-cup-seals-hydraulic-pneumatic","title":"Plastic Cup Seals (Hydraulic \u0026 Pneumatic Rod \u0026 Piston Seals)","description":"\u003ch3\u003ePlastic Cup Seals for Hydraulic \u0026amp; Pneumatic Cylinders\u003c\/h3\u003e\n\u003cp\u003eKaybin manufactures custom plastic cup seals for hydraulic and pneumatic cylinder applications where reliable dynamic sealing under pressure is required. These seals are used in reciprocating rod and piston systems and are machined or moulded to suit specific groove dimensions, extrusion gaps, and operating conditions.\u003c\/p\u003e\n\u003cp\u003eThis page covers plastic cup seals only — not chevron packing, O-rings, or rotary shaft seals.\u003c\/p\u003e\n\u003ch4\u003eWhat Is a Plastic Cup Seal?\u003c\/h4\u003e\n\u003cp\u003eA cup seal (also referred to as a U-type dynamic seal) is a pressure-activated sealing element used in reciprocating hydraulic and pneumatic systems. The lip geometry expands under pressure, increasing sealing force against the rod or bore surface.\u003c\/p\u003e\n\u003cp\u003ePlastic cup seals are typically manufactured from polyurethane (PU) or PTFE-based materials depending on pressure, friction requirements, and media compatibility.\u003c\/p\u003e\n\u003ch4\u003eApplications\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eHydraulic cylinder rod sealing\u003c\/li\u003e\n\u003cli\u003ePiston sealing in single-acting systems\u003c\/li\u003e\n\u003cli\u003ePneumatic cylinder air sealing\u003c\/li\u003e\n\u003cli\u003eIndustrial actuators\u003c\/li\u003e\n\u003cli\u003eMobile hydraulics\u003c\/li\u003e\n\u003cli\u003eMining and heavy-duty hydraulic equipment\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eRod vs Piston Configuration\u003c\/h4\u003e\n\u003cp\u003e\u003cstrong\u003eRod Cup Seals\u003c\/strong\u003e\u003cbr\u003eInstalled in the gland to prevent external leakage. Pressure acts from one direction.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePiston Cup Seals\u003c\/strong\u003e\u003cbr\u003eUsed to separate pressure chambers within the cylinder. Can be configured for single-acting or double-acting duty depending on system design.\u003c\/p\u003e\n\u003ch4\u003eMaterial Options\u003c\/h4\u003e\n\u003cp\u003e\u003cstrong\u003ePolyurethane (PU)\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eHigh wear resistance\u003c\/li\u003e\n\u003cli\u003eStrong extrusion resistance\u003c\/li\u003e\n\u003cli\u003eCommon for hydraulic oil duty\u003c\/li\u003e\n\u003cli\u003eSuitable for higher shock and side-load conditions\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePTFE (Virgin or Filled)\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eLow friction performance\u003c\/li\u003e\n\u003cli\u003eChemical resistance advantages\u003c\/li\u003e\n\u003cli\u003eSuitable where reduced stick-slip is required\u003c\/li\u003e\n\u003cli\u003eOften supported with energizers or backup rings\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMaterial selection depends on pressure, extrusion gap, temperature, fluid compatibility, rod speed, and surface finish.\u003c\/p\u003e\n\u003ch4\u003eGroove \u0026amp; Hardware Interface Considerations\u003c\/h4\u003e\n\u003cp\u003eCorrect cup seal performance depends heavily on groove dimensions and hardware condition. Key factors include:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eGroove width and depth\u003c\/li\u003e\n\u003cli\u003eExtrusion gap clearance\u003c\/li\u003e\n\u003cli\u003eRod\/bore diameter tolerance\u003c\/li\u003e\n\u003cli\u003eSurface finish (Ra value)\u003c\/li\u003e\n\u003cli\u003ePresence of backup rings (where required)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIncorrect groove geometry or excessive clearance can lead to extrusion, lip rollover, or premature failure.\u003c\/p\u003e\n\u003ch4\u003eCommon Failure Modes\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eSeal extrusion into clearance gap\u003c\/li\u003e\n\u003cli\u003eLip inversion or rolling\u003c\/li\u003e\n\u003cli\u003eBlow-by leakage\u003c\/li\u003e\n\u003cli\u003eHardening due to temperature\u003c\/li\u003e\n\u003cli\u003eSwelling from incompatible fluid\u003c\/li\u003e\n\u003cli\u003eAbrasive scoring damage\u003c\/li\u003e\n\u003cli\u003eSeal twisting during installation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eProper material and groove selection significantly reduces these failure risks.\u003c\/p\u003e\n\u003ch4\u003ePressure \u0026amp; Duty Segmentation\u003c\/h4\u003e\n\u003cp\u003ePlastic cup seals are typically selected for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eLow to medium pressure pneumatic systems\u003c\/li\u003e\n\u003cli\u003eMedium to high pressure hydraulic systems (design dependent)\u003c\/li\u003e\n\u003cli\u003eSingle-acting applications\u003c\/li\u003e\n\u003cli\u003eReciprocating motion systems\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eExact pressure capability depends on material hardness, clearance gap, and support ring configuration.\u003c\/p\u003e\n\u003ch4\u003eReplacement \u0026amp; Reverse Engineering\u003c\/h4\u003e\n\u003cp\u003eKaybin supports:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eHydraulic cup seal replacement\u003c\/li\u003e\n\u003cli\u003ePneumatic cup seal replacement\u003c\/li\u003e\n\u003cli\u003eOEM seal replication\u003c\/li\u003e\n\u003cli\u003eGroove dimension matching\u003c\/li\u003e\n\u003cli\u003eMaterial upgrades for improved service life\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e Samples or dimensioned drawings can be used to reverse-engineer discontinued or obsolete seal profiles.\u003c\/p\u003e\n\u003ch4\u003eEngineering Details Required\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eRod or bore diameter\u003c\/li\u003e\n\u003cli\u003eGroove width and depth\u003c\/li\u003e\n\u003cli\u003eWorking pressure and temperature\u003c\/li\u003e\n\u003cli\u003eFluid\/media type\u003c\/li\u003e\n\u003cli\u003eStroke length and speed\u003c\/li\u003e\n\u003cli\u003eSingle or double-acting configuration\u003c\/li\u003e\n\u003cli\u003eExisting material (if replacement)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIndustrial plastic cup seals manufactured and supplied across South Africa and Africa.\u003c\/p\u003e","brand":"kaybin","offers":[{"title":"Default Title","offer_id":45262445117612,"sku":null,"price":0.0,"currency_code":"ZAR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0706\/4790\/6476\/files\/kaybin-plastic-cup-seals-ptfe-nylon-pom-polyurethane-south-africa_webp.webp?v=1769072877","url":"https:\/\/kaybin.co.za\/products\/plastic-cup-seals-hydraulic-pneumatic","provider":"Kaybin","version":"1.0","type":"link"}