Abstract-Computer numerical control (CNC) and robotic welding have long been applied to industrial manufacturing in production lines. This paper introduces optimal control to layout the maneuvering sequence for a five-linked manipulator arm. Two-point boundary-value problem (TPBVP) is inevitable in most of the dynamic optimal control problem. Direct collocation with Nonlinear Programming (DCNLP) converts a TPBVP into a nonlinear programming problem. DCNLP has been extensively applied in solving the space and aircraft control problems but is not much adopted in solving robotic optimization problems. The paper requires a manipulator to weld up two cylinders which are intersecting and perpendicular to each other. A least energy maneuvering sequence is expected.