The thickness of a silicone seal determines the initial compression and assembly tolerance. When selecting the thickness, a comprehensive evaluation should be made, taking into account the housing clearance, tolerances, screw preload, and long-term rebound.
1. First, establish the dimensional chain
Selecting shims based solely on the nominal clearance can lead to overlooking the flatness of the housing and the cumulative tolerances of the parts.
- List the size ranges for the housing, grooves, and gaskets
- Identify the maximum and minimum compression states
- Consider the effects of warping on long, narrow or large, flat structures
2. Set a reasonable compression level
Insufficient compression can cause leaks, while excessive compression accelerates permanent deformation and increases assembly force.
- Determine the Design Window Based on Material and Cross-Section Shape
- Ensure continuous and uniform circumferential stress distribution
- Avoid excessive tightening of screws in specific areas
3. Sealing Surface Requirements
Surface roughness, steps, holes, and corners can all create leakage paths.
- Ensure the sealing surface is free of sharp burrs and scratches
- Allow sufficient sealing width around the hole
- Round the corners and check the fit.
4. Authentication Methods
It is recommended to determine the actual window size through post-installation pressure or water immersion testing.
- Comparison of Leakage and Assembly Force for Samples of Different Thicknesses
- Retesting After Heat Aging
- Disassemble the unit to check whether the compression marks are uniform.
FAQ
1. Does a thicker gasket provide a better seal?
Not necessarily. If it is too thick, it may cause over-compression, assembly interference, or uneven screw preload.
2. Can foam gaskets be used as a substitute for solid silicone?
Depending on the requirements for protection, temperature resistance, and long-term compression, verification through comparison based on actual operating conditions is necessary.