Compare vulcanized EMI O-rings vs. compression molded EMI O-rings and make the right choice for your next EMI shielding project.
Specialty Silicone Products (SSP) is manufacturing vulcanized and molded O-rings that provide shielding against electromagnetic interference (EMI) and radio frequency interference (RFI). The addition of our third extruder has allowed us to expand our bonded O-ring manufacturing and meet growing demand for reliable EMI/RFI O-rings made from the following shielding silicones:
- SSP-502-65 nickel-graphite filled silicone
- SSP-2368-65 MIL-DTL-83528 Type B silicone
- SSP-2486-70 MIL-DTL-83528 Type D silicone
- SSP-2529 nickel-aluminum filled silicone
The image for this blog entry is a close-up of the bond for an O-ring made of SSP-502-65.
Vulcanized EMI O-Rings
SSP offers a fully-vulcanized product for EMI/RFI O-rings that have a developed length of 7 inches or greater. The ends of the extruded EMI/RFI cord are hot vulcanized with conductive silicone instead of cold spliced with glue. There are three major advantages to vulcanization, a joining process where heat-activated adhesives are applied to cut ends that are pressed together.
First, the temperature range for the adhesive is the same as for the O-ring material itself. Second, the joint isn’t harder than the elastomer. By contrast, cold bonding creates a “hard spot” in the O-ring’s joint once curing has occurred. Third, the adhesive that SSP uses for vulcanized O-rings is electrically conductive. This reduces the risk of EMI/RFI leakage associated with non-conductive cold splicing.
Compression Molded EMI O-Rings
For smaller EMI/RFI O-rings, SSP can compression mold the O-ring in one full piece and eliminate the need for bonding or splicing. With our in-house CNC equipment, we can create tooling with shorter lead times and lower costs. Instead of waiting for an outside mold maker to produce your molds, SSP can get to work and get you the reliable EMI/RFI shielding that you need.
Do you need EMI/RFI O-rings? To learn more about how SSP makes them, or for additional information about our shielding silicones, contact SSP on-line or email Dominic Testo.
