O Rings - M Barnwell Services Ltd

lB A R N W E L L‘ O ’ R I N G SSpecial mouldingsAn extensive range of mouldings for individualapplications is available. Contact your nearest BarnwellService Centre for expert advice.Quality standardsThe cost-effective use of ‘O’Rings is influenced to a greatextent by the definition of quality criteria. The choice ofthe compound according to the quality characteristicsinfluence the costs and the reliability of use. ISO3601/3-DIN 3771/4 defines permissible form and surfacedeviations.Distinctions are made in the table between permissibleflaw sizes according to type characteristics.Type characteristic N.‘O’Rings falling under this characteristic meet therequirements made on a standard quality. They satisfy thedemands made on static and dynamic seals.If no other demands are specified, Barnwell supply ‘O’Ringswith type characteristic N.Type characteristic S.‘O’Rings falling under type characteristic S are subject toexceptional demands, e.g. for safety relevant components inautomobile engineering. The permissible flaw sizes are verylimited. This demands a greater process technology andstricter quality control procedures.TypesofdeviationLimits for permissible form and surface deviations in accordance with DIN 3771/4Type Characteristic NType Characteristic SCross sections in principle1.8 2.65 3.55 5.3 7.0 1.8 2.65 3.55 5.3 7.0d 2 Maximum Size d 2SizeOffset andformdeviationse e ee 0.08 0.10 0.13 0.15 0.15 0.08 0.08 0.10 0.12 0.13Bead, burr,offsetcombinedf 0.10 0.12 0.14 0.16 0.18 0.10 0.10 0.13 0.15 0.15ffNotchg 0.18 0.27 0.36 0.53 0.70 0.10 0.15 0.20 0.20 0.30ghh 0.08 0.08 0.10 0.10 0.13 0.08 0.08 0.10 0.10 0.13Deburringaread2-Deviations from the round cross section are permissible ifthe flattening has a smooth transition into the round surfaceand d2 is maintainedFlow lines(radialelongation isnotpermissible)jkjk0.05 x d 1 or 1) 0.03 x d 1 or 1)1.50 1.50 6.50 6.50 6.50 1.50 1.50 5 5 50.08 0.05Recesses,distortionl 0.60 0.80 1.00 1.30 1.70 0.15 0.25 0.40 0.63 1.00mlm 0.080.08 0.10 0.10 0.13 0.08 0.08 0.10 0.10 0.13Foreign particles- Not permissible1) Depending on which value is largerTelephone +44(0)121 429 8011 (20 lines) Fax +44(0)121 434 3016 Website www.barnwell.co.uk 29