Robot Joint End Cover in 7075-T6, Double Layer Stepped Cavities, 0.025 mm Coaxiality

About This Part

This cover closes the joint module of a robot arm, and it is a locating part, not just a lid. Its outside carries the fits: 101.6 K6 and 115 J6 transition fits register the cover to the module housing, the 125 mm diameter sets the envelope, and a 110 mm reference and 98 mm step complete the stack. Inside, the 111 H7 bore carries the bearing or seal seat, with 34 g6, 26 H7, 25 H7 and 24 mm diameters stepping down the axis. Coaxiality is held within 0.025 mm and parallelism within 0.025 mm, because a cover that locates a tenth off loads the joint bearings unevenly for the life of the robot.

The hole fields are dense and equally spaced: twelve 3.2 mm through holes and twelve M3 threads on the flange circles, twenty four 3.2 mm and twenty four 1.4 mm through holes on the outer rings, six R2.5 features drilled through in reverse, four 3.01 x 5 mm dowel features, five M2 threads 3 mm deep and four M2 through. Indexing the patterns is what lets the cover, housing and stator bolt up without hole-to-hole fighting.

Structure is a double layer of stepped cavities, which the turn-mill route cuts in one chucking so the fits share one axis with the bore. Unspecified bosses break at C0.5 and recesses at R0.2 per the drawing's general notes.

The finish is black anodize over a 180 grit bead blast, a hard matte surface that handles the abrasion of a moving joint and reads as finished equipment, not a machined blank. This is a controlled critical part: geometry and key dimensions are CMM verified in full, with thread plug gauges on every tapped hole.