Flexible assembly system for heat exchanger coils

This paper introduces the design and experimental validation of a flexible robotized work cell for automated assembly of bends on top of a heat exchanger coil. This automatic system is based on the use of a specifically designed end-effector, able to store several bends together and to singularize and insert them in the tubes. In this way, the pick-and-place operations that are typical in automated assembly are eliminated, thus dramatically reducing cycle time. Automatic bowl-feeders are used to serialize bends in the tool crib, where the end-effectors are refilled in hidden time after each tool change. A machine vision system identifies tube positions and detects defects on tube tops, to avoid insertion in damaged tubes. The insertion scheme is derived by comparing tube positions to those stored in a database, so the work cell can produce a highly variable product mix.