MIP-based heuristics for combinatorial design of reconfigurable rotary transfer machines for production of multiple parts

This paper deals with a problem of the optimal configuration of a rotary transfer machine with turrets for machining multiple parts. This is a hard combinatorial optimization problem appearing at the preliminary machine design stage. Such machines are multi-positional, i.e. parts are sequentially machined on several working positions. At each working position, several machining modules (spindle heads) can be installed to process the tasks assigned to this position. Machining modules are activated sequentially or simultaneously. Sequential activation is realized by the use of turrets. Simultaneous activation is possible if machining modules are related to the different sides of the part, and if they can work in parallel. There are horizontal and vertical spindle heads, and turrets to access different sides of the parts on a working position. At the preliminary design stage, the following decisions must be made: the choice of orientations of the parts on the rotary table; the partitioning of the given set of tasks into positions and their assignment to machining modules (selection or design of machining modules to use), and the choice of cutting modes for each spindle head and turret. The objective is to minimize the total cost of equipment used. The number of possible solutions for this combinatorial design problem increases exponentially with the number of part types to be produced, and this represents a computational burden for decision-makers (usually process engineers). In this paper, in order to help decision makers deal efficiently with the manufacturing of multiple batches of parts, we develop a powerful heuristic framework which can be used in real life industrial cases. We test the developed methodology on the real-life cases provided by one of our industrial partners and demonstrate its efficiency. The proposed model and algorithms allow to minimize the cost of designed machines.