Technical Literature

Small Seals, Big Decisions: Microminiature O-Ring Success and Material Selection

Microminiature o-rings may be tiny, but they play a huge role in many industries by ensuring that seal integrity is maintained in miniature applications. These components significantly contribute to the overall performance and reliability of various systems. Let’s take a closer look at how material selection impacts their performance.

1. Material Selection Factors

a. Chemical Compatibility

Micro o-rings come into contact with different fluids and chemicals based on the application. Choosing materials involves strict adherence to chemical compatibility criteria. Compatibility charts are essential for cross-referencing the resistance of candidate materials to various chemicals.

b. Temperature Range

Exposure to extreme temperatures requires materials that can withstand both high and low conditions. Knowing the specific temperature range of the application is crucial for selecting materials that maintain their structure and flexibility.

c. Compression Set Resistance

In precision sealing at a micro-scale, a material’s ability to recover its original shape after compression (compression set resistance) is vital. Opting for materials with low compression set ensures a reliable and consistent seal over time.

d. Hardness and Elasticity

The hardness and elasticity of the material influence its ability to form a proper seal and resist deformation under pressure. Striking the right balance between hardness and elasticity is crucial for an effective seal without compromising durability.

2. Common Materials used for Micro O-Rings

a. Silicone

Known for flexibility, a wide temperature range, and resistance to aging, silicone is a popular choice for micro o-rings, especially in medical and pharmaceutical applications.

b. Fluorocarbon

Recognized for chemical resistance and high-temperature tolerance, fluorocarbon is suitable for applications with exposure to aggressive chemicals and elevated temperatures.

c. Nitrile (Buna-N)

A versatile material with excellent resistance to oils and fuels, nitrile is commonly used in automotive and industrial applications where exposure to oil and fuel is a concern.

3. Specialized Applications

Certain micro-scale applications require specialized materials like perfluoroelastomers (FFKM) or ethylene propylene diene monomer (EPDM), offering enhanced performance in specific environments.

4. Testing and Validation

Before finalizing material selection for micro o-rings, comprehensive testing for chemical resistance, compression set, and temperature stability is crucial. This ensures that chosen materials meet the specific requirements of the application.

Have questions about micrOring material selection?

Contact one of the engineers at Apple Rubber.