Constructing a punch press for small-scale manufacture of crossflow turbines

To produce good quality metal products in these regions, techniques need to be adapted to existing equipment and available raw materials. This paper describes a punch press which enables metal processors in eastern Zaire to produce commercially viable, hydropowered grain mills. The press is a refinement of a well-known, traditional technology, used mostly in machinery driven by air or hydraulic pressure, to allow for use in small-scale manufacturing. Initial surveys indicate that the grain mills give poor people access to a milling capacity not otherwise available. Reportedly, women now use the time they save by having their corn or cassava milled to market extra produce or to engage in other income-generating activities. Included in the paper are chapters on: (1) punch and die applications to small-scale manufacture; (2) design and construction of punches, dies, and presses in small workshops; (3) use of a punch press in small-scale manufacture of cross-flow turbines; (4) design and construction of a punch press for slotting turbine runner disks; and (5) the impact of the punch press on turbine manufacture in eastern Zaire. This technical description, not meant to be a step by step manual for the production and use of a punch press, is designed to help promote discussion between the professional technician and a local producer or entrepreneur searching for an appropriate technology.