Perlast® Groove Design for Semiconductor Applications

Groove volume should be tailored to allow for the coefficient of thermal expansion, ensuring that 100% gland-fill is not reached.

The linked tables provide design guidelines for rectangular grooves, double dovetail grooves and single dovetail grooves when using Perlast® perfluoroelastomers and Kimura™ K13X.

Recommended double dovetail groove dimensions, optimized specifically for Perlast materials (PDF).

Static rectangular face seal grooves Rectangular face seal grooves are the most common form of O-ring grooves utilized on semiconductor, FPD and TF solar capital equipment. Typically vacuum is applied to facilitate process reactions, resulting in externally-pressurized face seals.
The degree of stretch applied to the inside diameter of the O-ring is just enough to take up manufacturing tolerances and ensure that the O-ring sits upon the inside of the groove. The amount of compression (squeeze) applied to an O-ring can affect the total useful operating life of the seal. Groove volume should be tailored to allow for the coefficient of thermal expansion, ensuring that 100% gland-fill is not reached. Recommended rectangular groove dimensions, optimized specifically for Perlast materials (PDF).
Double dove-tail face seal grooves Grooves of dovetail shape can be used to ensure that O-rings are retained in the groove. The width at the top of the groove is defined such that there will always be interference with the O-ring. However, the use of these grooves increases gland-fill and may lead to thermal extrusion. Many dove-tail grooves are designed for use with FKM materials.
FFKM materials have a higher coefficient of thermal expansion. Thermal expansion and maximum operating temperatures have been considered in the groove dimensions on the following pages. Recommended double dovetail groove dimensions, optimized specifically for Perlast materials (PDF).
Single dove-tail face seal grooves Single sided dovetail shaped grooves utilize stretch to ensure that O-rings are retained in the groove by the undercut, which is applied to the inside of the groove. The degree of stretch that should be applied to the O-ring is modulus specific, low modulus materials should be stretched to a greater degree than high modulus ones.
High: 100% Modulus > 8Mpa i.e. K13X, G75H Low: 100% Modulus < 8MPa i.e. G67P, G74P, G100XT Recommended single dovetail groove dimensions, optimized specifically for Perlast materials (PDF).