| Seal Design | Seal geometry and application fit | - O-ring, gasket, lip seal, bonded seal, or custom profile
- Static or dynamic sealing duty
- Groove dimensions, compression, tolerances, and installation direction
| Design should follow the applicable equipment drawing, groove standard, and installation requirements. ISO 3601 is commonly used for O-ring dimensions and tolerances. | Approved drawings, dimensional inspection reports, design calculations, and installation instructions. |
| Air-Tight Performance | Leakage control under the intended pressure and vacuum conditions | - Test pressure and vacuum level
- Test medium, temperature, duration, and allowable leakage rate
- Static or dynamic test configuration
| Acceptance limits should be defined by the product specification and application risk. Helium leak testing is more sensitive than many air-pressure bubble tests and should be specified when very low leakage is critical. | Leak-test procedure, calibrated equipment records, test reports, sample size, and pass/fail criteria. |
| Material Selection | Compatibility with temperature, pressure, fluids, and gases | - Elastomer family: NBR, EPDM, FKM, silicone, or other specified material
- Hardness, typically expressed in Shore A
- Temperature range and fluid exposure
- Compression set and swelling resistance
| Material suitability depends on the exact medium and operating conditions. NBR is widely used with mineral oils; EPDM is generally suitable for water and many glycol-based fluids but is not suitable for petroleum oils; FKM offers broad chemical and high-temperature resistance but must be checked for low-temperature use. | Material specification, compound identification, certificate of analysis, safety data, and compatibility test results. |
| Temperature Capability | Retention of elasticity across the operating temperature range | - Continuous and intermittent temperature limits
- Low-temperature flexibility
- Heat aging, hardening, cracking, or softening
| Published temperature ranges are compound-dependent and should not be treated as universal values. Qualification should cover the actual minimum, maximum, exposure time, and pressure conditions. | Technical data sheet, thermal aging results, low-temperature test data, and application-specific validation report. |
| Pressure and Compression | Resistance to extrusion, blow-by, and loss of contact pressure | - Maximum working pressure
- Pressure cycling and impulse exposure
- Clearance gap, gland fill, compression, and back-up ring requirements
| Pressure capability depends on seal design, material hardness, temperature, clearance, and lubrication. A pressure rating without application conditions is not sufficient for comparison. | Pressure-test results, gland design data, extrusion-resistance assessment, and recommended back-up configuration. |
| Durability | Service life under repeated movement or pressure cycling | - Number of cycles or operating hours
- Movement speed, stroke, rotation, and lubrication
- Wear, abrasion, tearing, and permanent deformation
| Dynamic seals require application-specific endurance testing. Static seal test results should not be used as proof of dynamic service life. | Endurance-test method, cycle count, operating conditions, failure criteria, and post-test inspection records. |
| Compression Set | Ability to maintain sealing force after long-term compression | - Compression-set percentage
- Test temperature and duration
- Recovery after fixture removal
| ASTM D395 is commonly used for compression-set testing of rubber materials. Results are meaningful only when the test method, temperature, time, and specimen type are reported. | Laboratory test report, compound designation, test conditions, and acceptance limits. |
| Material Testing | Consistency of physical and mechanical properties | - Hardness
- Tensile strength and elongation
- Tear resistance, density, and dimensional stability
| ASTM D2240 is commonly used for Shore hardness, while ASTM D412 is commonly used for tensile properties of vulcanized rubber and thermoplastic elastomers. | Batch test reports, laboratory calibration records, lot traceability, and control limits. |
| Dimensional Quality | Fit, interchangeability, and repeatable installation | - Inside diameter, outside diameter, cross-section, profile, and flash
- Visual defects, surface finish, parting line, and mold marks
- Measurement equipment and inspection frequency
| Dimensions should be controlled against the approved drawing or applicable dimensional standard. ISO 3601 may apply to specified O-ring sizes and tolerances. | First-article inspection, in-process inspection plan, final inspection report, and sample approval records. |
| Regulatory Compliance | Suitability for the destination market and end use | - Food, drinking-water, medical, automotive, aerospace, or industrial requirements
- Restricted substances and declarations of conformity
- Traceability and change-control obligations
| Requirements vary by application and jurisdiction. For food-contact rubber articles in the United States, 21 CFR 177.2600 may be relevant; it should be checked against the exact formulation and use conditions. | Declaration of conformity, applicable test reports, restricted-substance statement, formulation control, and change-notification procedure. |
| Quality Management | Process control and prevention of recurring defects | - Quality-management certification and scope
- Nonconformance control and corrective action
- Process capability, inspection planning, and internal audits
| ISO 9001 provides a general framework for quality-management systems. Certification does not by itself prove that a specific seal design or material is suitable. | Valid certificate, audit summary, process-control plan, corrective-action records, and key-process monitoring data. |
| Batch Traceability | Ability to identify the material and production history of every shipment | - Lot number and production date
- Compound or material batch
- Mold, machine, inspection status, and packaging reference
| Traceability should connect finished parts to raw-material records, production records, inspection results, and shipment documentation. | Lot-traceability sample, batch certificate, retention policy, and recall or containment procedure. |
| Packaging and Storage | Protection against ozone, heat, light, contamination, and deformation | - Individual or bulk packaging method
- Storage temperature, humidity, light, and ozone exposure
- First-in, first-out inventory control
| ISO 2230 provides guidance for the storage of rubber products, including factors such as temperature, humidity, light, ozone, and deformation. | Packaging specification, storage instructions, shelf-life statement, warehouse controls, and shipping inspection records. |
| Supplier Capability | Ability to provide stable quality at the required volume | - Tooling and mold capacity
- Production capacity and lead-time range
- Subcontractor control and contingency planning
| Capacity claims should be supported by recent production records, equipment lists, staffing plans, and documented capacity assumptions. | Capacity statement, manufacturing-flow chart, equipment list, production schedule, and business-continuity plan. |
| Commercial Reliability | Predictability of cost, delivery, and technical communication | - Quotation validity and tooling charges
- Minimum order quantity and standard lead time
- Incoterms, export documents, and response time
| Commercial terms should clearly separate recurring part costs, one-time tooling, testing, packaging, freight, duties, and other destination-specific charges. | Detailed quotation, sample schedule, delivery-performance records, export-document checklist, and escalation contacts. |