Repeatable positioning and rigid coupling are critical to manufacturing processes. Traditionally, pin joints and elastic averaging methods have been used to create reasonably repeatable and stiff joints. However, for repeatability below 200 μinches (5μm) these methods become expensive to manufacture. Less often used, are kinematic couplings which can attain sub-micron level repeatability, but have limited stiffness and don’t allow the mating of surfaces (as required in casting.)
In this paper, a new type of coupling, a compliant kinematic coupling, which combines the desirable characteristics of many methods is presented. The result is a coupling with the stiffness characteristics of elastically averaged couplings, good repeatability, and the ability to allow surfaces to mate. Repeatability tests in low cost versions of these couplings show radial repeatability of 200μinch (5μm) and angular repeatability of 57 μradians. This coupling method can be used in casting, assembly, fixturing, sheet metal forming, and other processes.