Optimal tool magazine operation. Part 1: Rotating magazines with unbuffered tool change

Abstract

Minimisation of tool change waiting time of numerically controlled machine tools is studied for machines equipped with tool revolvers or rotating tool magazines and unbuffered tool change. The tool order in the magazine is optimised with the primary objective of minimising the time required for tool magazine rotation and tool change. Numerical experiments are conducted and their results show that optimisation of tool locations of a fixed tool position revolver or revolver type magazine is usually always useful. The optimisation is most beneficial when the magazine is large and the tool usage frequency distribution is non-uniform. Savings of 60% on waiting time are typical compared to the use of a random tool order in the magazine. A tool magazine operating method utilising empty tool slots in the magazine is examined and found to be useful. Rotating tool magazines equipped with a buffering tool changer are studied in the accompanying Part 2 of the paper.