Meaning
Kinematic coupling mechanisms providing six points of contact ensure the exact and repeatable relocation of a component in a mechanical assembly. The kelvin clamp uses a combination of three spheres resting in a V groove, a pit and a flat to constrain all degrees of freedom. It prevents overconstraint and allows for sub micron repositioning without the need for manual alignment.
Kinematic Restraint
Contact points are arranged to provide a unique location in space for the coupled part. Using a kelvin clamp eliminates the play found in traditional pinned joints or bolted surfaces. This design is preferred for modular tooling and interchangeable laser optics where accuracy is paramount.
Interfacial Friction
Material choice for the contact balls and seats affects the stability of the mount. Hardened steel or tungsten carbide prevents wear at the contact interface during repeated docking cycles. Lubrication is avoided to prevent the buildup of contaminants that would degrade the repeatability of the kelvin clamp.
Error Budget
Repeatability of the mount is measured by removing and replacing the component multiple times while tracking the position with an indicator. This test distinguishes the mechanical capability of the coupling from the resolution of the adjustment screws. The cost of a failure in this interface is a loss of system calibration and increased downtime.
