PEEK and PEI Connector Insulation Parts

For connectors, especially for the high-frequency and radio-frequency connectors, besides the excellent design and manufacturing technique, another critical factor in determining whether the products are good is the plastic because the function of plastic in the connectors applications is insulation. 

Usually, the connectors are tiny, and the typical diameter ranges from 3mm to 10mm. It required excellent insulation properties and superb machinability, dimensional stability. At the same time, the less dielectric loss, the better. So the dielectric constant of plastic must be low. Considering all these factors, the most commonly used materials in the connector application are PEEK and PEI.

Why use PEEK and PEI

• the good electric properties

The dielectric constant of PEEK and PEI are relatively low, and they are 3.0 and 3.15 at 1 kHz. The electric properties make the dielectric loss less.

• the good mechanical performance 

These two materials’ tensile strength, compression strength, and flexural strength are all above 100 Mpa. Moreover, PEEK and PEI’s long-term working temperatures are 260℃ and 170℃. The high thermal stable performance also makes the material cope with extreme working conditions.

What other plastic can be used in connectors?

The plastics only require good insulation properties for the non-high frequency connectors. So literally any material which could meet the temperature and insulation demand is suitable. But there are two leading plastics used in this situation.

• PTFE

This material shows an even lower dielectric constant which is 2.1 at 1kHz. But the mechanical properties are relatively low. When machining, PTFE offers ‘softer’ than other plastics.

• PPS

This plastic shows high service temperature, good mechanical strength, and excellent insulation properties. But the dielectric constant is relatively higher than PEEK and PEI. So PPS is suited for the connector’s shell.