Network part program approach based on the STEP-NC data structure for the machining of multiple fixture pallets

Abstract

The adoption of alternative process plans, that is, process plans that include alternative ways of machining a workpiece, can improve system performance through a better management of resource availability. Unfortunately even if this opportunity is deeply analysed in literature, it is not frequently adopted in real manufacturing practice. In order to fill this gap, this article presents the network part program (NPP) approach for the machining of multiple fixture pallets. The NPP approach is based on the STEP-NC data structure which supports nonlinear sequences of operations and process flexibility. In the NPP approach, a machining system supervisor defines the machining sequences and generates the related part programs just before the execution of the pallet. This article provides an approach with high scientific value and industrial applicability based on the integration of new and existing process planning methods. A real industrial case study is considered in order to show that in real applications the final quality is unaffected by the change of the sequence of the operations due to the employment of nonlinear process plans. Since the results appear very encouraging, the proposed approach is a possible solution to accelerate the adoption of nonlinear process planning in real manufacturing practice

Design and management of manufacturing systems for production quality

“…A first attempt to develop NPP on industrial scale was led in the Italian national project NetPP [21] where the approach was limited to the production of pallets mounting one single part type on one work area. Non-linear process planning able to support the configuration of multi-fixtures (pallet) with different parts has been later developed [217] for managing small batches and a high number of product variants.…”

Exploiting Modular Pallet Flexibility for Product and Process Co-evolution Through Zero-Point Clamping Systems

“…Such limitations regarding the pallet configuration can be properly addressed only by jointly tackling also the process planning in a modular way, e.g. by defining the machining process as a Network Part Program (NPP) [11] that is a process plan (and then a part program) defined in terms of a Directed Acyclic Graph (DAG). An approach for pallet configuration based on NPP to deal with the simultaneous machining of different workpieces on the same pallet has been recently proposed [12].…”

Feature-based adaptive numerical control programming method for the environment of changing manufacturing resources

“…Wosnik et al 14 introduced a generic approach to preprocess and feed process data back from servo drives to CNC and computer-aided process planning (CAPP) systems. Borgia et al 15 presented a network part program approach for the machining of multiple fixture pallets, which is based on the STEP-NC data structure so as to support nonlinear sequences of operations and process flexibility. Choi et al 16 presented the development and data management of Turn-STEP to support intelligent manufacturing and autonomous execution of NC machines.…”