Overview

The ideal assembly fixtures let the assembler work with both hands, present all points of assembly in an ergonomically appropriate orientation, dock as needed in automatic equipment, double as a kit pallet for product-specific parts, and if possible can hold more than one product. Fixtures for manual assembly travel through multiple stations, and need to return afterward to the first station at which they are used, traveling above or below the assembly line.

Fixtures for mechanized assembly hold parts with clamps or pneumatic cylinders and must be oriented for easy loading and unloading. The machine must be prevented from starting while the operator's hands are inside, but the most common approach dual finger switches is a productivity drag in short cycle jobs; therefore, equally safe but more productive alternatives need to be sought on a case-by-case basis. In-line mechanical automation is a alternative to offline robotics that is cheaper in high-volume applications and relies on jigs and locating pins to align components.

Hand tools must be attached to the station and not to the assembler, positioned within arm's reach, oriented for immediate use, and as much as possible fitted with a mechanism to return them automatically after use. On large products, "nagara"fixtures are used to keep tools aligned with moving product.

Assembly instructions are provided in 11-inch by 17-inch sheets posted at eye level at each station, rather than in binders. These sheets contain a drawing or photograph, surrounded with blocks of text with sequences of operations,...