Assembly lines are designed for the sequential organization of workers, tools or machines and parts. The motion of workers is minimized to the extent possible. Each worker typically performs one simple operation.
The principles of assembly are these
Place the tools and the men in the sequence of the operation so that each component part shall travel the least possible distance while in the process of finishing.
Use work slides or some other form of carrier so that when a workman completes his operation, he drops the part always in the same place. Which place must always be the most convenient place to his hand and if possible have gravity carry the part to the next workman for his own.