Isolation mounts, bushings, and vibration components depend on the interface between the elastomer and the metal. By the time a bond fails in service, the decision that caused it was usually made during design.
1. The substrate, and how it will be prepared
Steel, stainless, and aluminum do not prepare the same way. Blast profile, degreasing, and how long a prepared part sits before priming all affect the bond. Prepared metal does not stay ready indefinitely.
2. Geometry and draft
The shape of the bonding area matters as much as the adhesive. Sharp transitions concentrate stress at the bond line. Adequate draft and generous radii cost nothing on a drawing and a great deal in a mold.
3. Compound and adhesive chosen together
The elastomer, the metal, and the bonding agent are one system. An adhesive that works with nitrile on steel is not necessarily right for EPDM on aluminum.
4. The failure mode you will accept
A part that fails at 950 pounds with a clean metal surface is worse than one that fails at 700 pounds and tears the rubber. The first never fully bonded. Specify the failure mode, not only the load.
5. Verification before the tool is cut
We test the bond with the production compound, on the production substrate, before tooling. Finding an adhesive problem at first article is expensive and avoidable.
Bring us the print early if you can. Most of the above is cheap to change on a drawing and costly to change in steel.