Abstract
A problem to minimize the number of tool exchange times is one of tool module design problems for a numerical controlled complex machine. In this study, we propose two approximate solutions that take note of tools and parts to generate a smaller number of tool modules. As the results of computational experiments, in the first solution to take note of tools, we find a rule to select "seed tools", which can produce a part using the largest number of tools, and also choosing additional tools, for which the ratio of the number of common tools with "seed tools" is maximal, and allow us to improve the solution. In another solution paying attention to parts, we find a rule to select them with minimum degree of node, which indicates the relation between parts, and chooses additional parts, which use minimum number of tools, to have the nearly optimal solution in some cases. This solution has the merit of being able to confirm the accuracy of an approximate solution based on its lower limit value.
