Pallet operation sequencing based on network part program logic

Abstract

Abstract CAPP systems play a relevant role in aiding planners during setup planning, operation sequencing and pallet configuration activities. The support and automation granted by these techniques, together with the use of non-linear process planning logic, lead to a reduction in the planning time and costs, thus making manufacturers more competitive. This paper presents an approach that integrating process and production planning leads to the definition at the shop-floor level of the optimal operation sequence to machine all of the workpieces on a pallet using a four-axis machine tool. Part programs of non-production movements for each possible sequence of two operations are automatically generated at the shop-floor level and are simulated to obtain the non-production time. The complete sequence of operations is then defined on the basis of the minimisation of the estimated non-production time. This minimisation is performed using a mathematical model that defines a good sequence of operations. Four algorithms are adopted to analyse the proposed solution and to reduce the gap from optimality. The approach is tested on some cases taken from literature and on a real case. The real case was provided by a company that produces mechanical components. The obtained results underline a reduction on production and planning time, and consequently an increment in the company profit.