For manual assembly; the process, access, movement, resistance, and alignment of the parts are considered. Time penalties are given to those parts which have difficulties in excess of handling and assembling a standard part. A design efficiency can be calculated for the existing design. The task of the design team is to increase this efficiency and reduce the factory cost. The efficiency can be increased by similar methods to be described for automatic assembly.
Product design for automatic assembly can be implemented at any stage
in the manufacturing process. It is best, however, to design for
automatic assembly before the product goes into production. The
problems associated with re-design, once the product has gone into
production are many. Firstly, the cost of design changes, in terms of
re-tooling, may outweigh the savings gained by greater productivity.
Secondly, an unacceptable lead time may exist from company approval and
customer approval to getting the re-designed product into production.
Also, once a product has been redesigned for automatic assembly, good
productivity gains can often be realized by incorporating the new
product into an existing manual assembly line, without investment in an
automatic assembly system. This highlights the fact that a product
re-designed for automatic assembly always provides savings in manual
assembly, when compared with an existing design.
The object of a design for automatic assembly investigation is to increase the design efficiency of the product.