Partially cured molded cord is joined and molded under pressure and high temperature in a tool/fixture. Depending on size multiple joints could be used. The finished seal is then placed in a high temperature post cure oven to complete the cure. After the o-ring is fully cured, it is de-flashed and buffed if required. ID dimensional tolerances per quote.
Potential slight over-fill at joint (Exaggerated Renderings to describe potential issues)
Potential slight under-fill at joint could lead to leaks in some applications
Parting line and flash can be misaligned at joint
Buffing at the joint can yield variable surface finish from the rest of the part