| 摘要 |
Parallelism between two opposite surfaces of workpiece (106) is assured by referencing of three features of the edge(s) of the workpiece, the three edge features establishing a single, unique plane within the workpiece for referencing the machining operations performed on the two opposite surfaces of the workpiece. The workpiece is held by corresponding two sets of three fixture points (214a, 214b, 214c and 264a, 264b, 264c), above the surface of two corresponding fixtures (208, 258) or of one compound fixture, while machining the two opposite surfaces (206a, 206b). In this manner, problems associated with referencing off of the first machined surface, to machine the second surface, are completely avoided. This is particularly useful when machining the opposite faces of an automatic transmission valve body. The one set of fixture points is identical to the other set of fixture points, to ensure accurate positioning of the workpiece from fixture-to-fixture, or from set of fixture points to set of fixture points, in a compound fixture. |
