Coupling Design Process: Coupling Selection
The second step in the coupling design process is the selection of the coupling type. This selection process is most easily done by comparing the critical design parameters with the capabilites of the basic coupling types using some form of comparison table. For example, a Pugh chart or weighted decision chart could be used. The selection process is difficult due to the adaptability of each coupling type to the design requirements. General trends in the abilities of the different coupling types are shown in the table below.
| Coupling Type | Contact Type | Repeatability | Stiffness/Load Capacity | Industrially Ideal |
|---|---|---|---|---|
| Basic Pin Joint | Surface | Poor (~5µm) | High | Fair |
| Elastic Averaging | Surface | Fair (~1µm) | High | Good |
| Planar Kinematic | Mixed | Good | High | Good |
| Quasi-Kinematic | Line | Good (~0.5µm) | Medium to High | Good |
| Kinematic | Point | Excellent (~0.01µm) | Varies (Usually Low) | Poor |
