C/S tolerances of Molded vs Vulcanized O-Ring Cord

There is a great amount of difference between molded and vulcanized O-Rings. Extruded Cord's cross-section tolerance are different because of the manufacturing process, parts are extruded through a die. Standard molded O-Rings have a tighter tolerance than the vulcanized extruded cord. Standard molded O-rings are made is a large cavity press, material is injected into tight tolerance molds to form the correct size of a molded O-ring.  Although, for some applications, molded O-Rings can be impractical for several reasons depending on your application and manufacturing needs.

The extruded cord that is used to manufacture custom vulcanized O-rings has many pros. You can use the cord in the field to make your own O-rings. Saving down time on waiting to obtain Molded parts.

For further clarification and to see how C/S tolerance differs between molded and vulcanized O-Ring Cord, let's take an example.

This is based on Buna 70D

000 AS568 series tolerances are +/- .003", on extruded cord .070" cross section the tolerances are +/-.008"

100 AS568 series tolerances are +/- .003", on extruded cord .103" cross section the tolerances are +/-.010"

200 AS568 series tolerances are +/- .004", on extruded cord .139" cross section the tolerances are +/-.010"

300 AS568 series tolerances are +/- .005", on extruded cord .210" cross section the tolerances are +/-.014"

400 AS568 series tolerances are +/- .006", on extruded cord .275" cross section the tolerances are +/-.016"

Similarly, other materials of extruded cord have different tolerances as well.

To know more about the C/S tolerance of different materials, contact COR Manufacturing. Our expert team can guide you to select the right material for your specific application.