Ensuring economic efficiency of flexible fixtures in multiproduct manufacturing

The first-priority directions for modern engineering, especially for multiproduct manufacturing, include the intensification of manufacturing processes, increasing the efficiency of technological equipment, and reducing the time required to implement technological solutions. Fixture design is a complicated and time-consuming process that requires considering many parameters of the closed-loop technological system “machine tool — fixture — cutting tool — workpiece”. One machined part can have several fixture layouts corresponding to all specified parameters; however, their effectiveness differs depending on production conditions. Search for an optimal fixture for specified production conditions is an essential stage of production planning. It has been proved that the efficiency of a manufacturing process should be assessed using single economic indicator — the cost of machining, which considers the costs of time, the total costs for process realisation, and a batch of parts. The paper aims to substantiate the efficiency of manufacturing processes in machining complex parts using flexible fixtures by developing a mathematical model that considers the cost of time, the cost of implementing the manufacturing process, and the batch value of parts production. This approach estimates the efficiency of manufacturing processes for machining complex parts and choosing the flexible fixture layout that corresponds to specific production conditions. It was proved that flexible fixtures could be effectively used for machining small batches of parts with frequent readjustments to new workpieces and short-term machining. A tendency has been established that the higher number of nomenclature of parts contributes to expanding the scope of the effective use of flexible fixtures.