Criteria for the choice of work pieces for conventional or Numerical-Control (NC) manufacturing (turning, drilling, and cutting)

Methods to prepare and check the use of conventional and numerical control (NC) machines in research workshops where single and prototype manufacturing prevail are discussed. The methods permit determination of which work pieces are suited for conventional and which for NC-machining. The methods of qualified work piece visual assessment and of the comparison of fabrication costs provide evaluation criteria. Starting from manufacturing-relevant geometrical and technological characteristics, the work pieces to be produced can be objectively classed with a single machine type. The results over a one-year period can give a reliable basis for long term investment decisions. If the requirements are fulfilled, conventional machines should be replaced by NC-machines, although the number of NC-machines is very limited compared to conventional machines.