Molded Rubber Part

Molded rubber parts are widely used in automotive, industrial, and consumer applications for sealing, vibration isolation, and environmental protection. They are specified by material type (e.g., NBR, EPDM, silicone), hardness (Shore A), dimensions, and performance requirements such as temperature resistance and compression set. Grades are distinguished by the base polymer, filler content, and curing system, which affect properties like oil resistance, weatherability, and durability. This directory entry provides reference data for typical molded rubber parts, including material options such as NBR, EPDM, silicone (VMQ), FKM, and CR. Key parameters include hardness (30–90 Shore A per ISO 7619-1), tensile strength (5–25 MPa per ISO 37), elongation at break (100–600% per ISO 37), compression set (10–30% at 70°C for 22h per ISO 815), operating temperature range (-40 to 150°C), tolerance class (M1–M3 per ISO 3302-1), surface finish (Ra 0.8–3.2 μm), tear strength (20–80 kN/m per ISO 34-1), density (1.1–1.6 g/cm³ per ISO 1183), volume resistivity (10^10–10^15 Ω·cm per ASTM D257), dielectric strength (10–30 kV/mm per ASTM D149), abrasion resistance (50–200 mm³ volume loss per ISO 4649), ozone resistance (no cracks after 72h per ISO 1431-1), oil resistance (0–30% volume change in IRM 903 oil, 70h at 100°C per ASTM D471), and color (black standard, custom available). Relevant standards include ISO 3302-1, ASTM D2000, GB/T 5720, and DIN 53505. These values are typical ranges and must be verified with the manufacturer for specific applications. The directory does not certify compliance; always confirm model-specific data with the legal manufacturer or supplier.

The part works by deforming elastically under load, providing a barrier against fluids or gases, absorbing vibration, or maintaining contact pressure. Its performance depends on the elastomer's viscoelastic behavior, which allows it to recover its original shape after deformation, and its ability to maintain sealing force over time. The elastic deformation is governed by the material's hardness and crosslink density, while the recovery is influenced by compression set. In sealing applications, the part must maintain sufficient contact pressure to prevent leakage, which requires proper design of the cross-section and interference fit. In damping, the viscoelastic properties dissipate energy. The operating temperature range and chemical resistance determine the suitable material. Failure can occur due to excessive compression set, thermal degradation, or chemical attack, to loss of sealing force or cracking. Regular inspection for cracks, permanent deformation, or hardening is recommended.