A Framework Of Next Generation Adaptive CNC Controller

Modern manufacturing industries have increasingly demanded to bring comprehensive input data described using high-level languages such as STEP-NC, rather than outdated G&M codes into computer numerical control machine tool levels. In current dynamic shop floor environments, predefined numerical control (NC) command generated in early stages is regularly found unusable or unsuitable for the dedicated resources, causing useless efforts used up in the initial process planning and NC code generation. This research aims to propose a new structure of an adaptive CNC controller by taking the advantages of well-known IEC61499 and STEP-NC standards.For realising adaptive CNC controller capability, integration of the native process planning decision-making function into CNC controller will be established. The activities such as cutting tool selection, machining parameter determination and toolpath generation will be issued automatically by the controller itself that subject to available online machine resources. The generic STEP-NC file is employed as data input and arranged accordingly in the IEC 61499 function block software editor. The system is developed in the JAVA environment by using proposed language

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

partially_open4noThe 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.S. Borgia; S. Pellegrinelli; S. Petro'; T. TolioBorgia, Stefano; Pellegrinelli, Stefania; Petro', Stefano; Tolio, TULLIO ANTONIO MARI

STEP COMPLIANT APPROACH FOR TURN-MILL OPERATIONS

Current machine tools have incurred challenges on limitation such as part programming complexity of G and M code, weak integration of digital machine tools and coverage of universal data modeling for product and manufacturing resources. In response to this manufacturing system requirement, Standard for Exchange of Product data (STEP) and its implementation on developing an interface for the next generation of machine tool controllers (STEP-NC) has become a concern of research interest and performed on basic manufacturing technology limited to a unit domain such as turning, milling or Wire EDM. Therefore; extending this STEP implementation on multipurpose machine tools such as turn-mill machines is mandatory since the machines are the main component in these industries. The research work offers a STEP-NC compliant interface supporting turn-mill machining environment identified as SCSTMO

Um Sistema para o projeto e fabricação de peças mecânicas a distância via internet aderente à norma ISO 14649 (STEP-NC)

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia MecânicaCom o rápido avanço da tecnologia da informação associada à tecnologia da fabricação, os ambientes de manufatura mudaram significativamente nas últimas décadas. A usinagem de alta velocidade, usinagem de ultra-precisão e usinagem de múltiplos eixos tem melhorado a produtividade e a qualidade da manufatura. Além disso, a tecnologia da internet introduziu a e-manufatura (isto é, projetado por qualquer um em qualquer lugar, fabricado por qualquer um em qualquer lugar). A chave para o sucesso da e-manufatura consiste em um fluxo de dados compatíveis e sem brechas na cadeia CAD-CAPP-CAM-CNC. Apesar do avanço nas tecnologias de manufatura, a linguagem que as máquinas de comando numérico utilizam nos dias de hoje (código G # norma ISO 6983) ainda baseia-se nas movimentações da extremidade das ferramentas e no status da máquina, fazendo com que muitas informações acerca do produto sejam perdidas, tornando difícil ou impossível o compartilhamento de tais informações em diferentes áreas da empresa. O padrão ISO 14649 (STEP-NC) fornece um modelo de informações de alto nível referentes ao produto, como por exemplo o uso de features para a modelagem de peças e operações de fabricação, e este padrão tem sido apontado como uma ferramenta adequada para superar os problemas acima mencionados. Assim, para um mercado onde é bastante comum a elevada variabilidade das peças sendo produzidas, a alteração nas features que compõem a peça é mais rápida e fácil do que a alteração do código G para a usinagem da peça, e desta forma capacita-se as empresas a responderem mais rapidamente à mudança no projeto das peças, além de contribuir para acelerar a tomada de decisões referentes à fabricação das peças. Uma outra vantagem do uso de STEP-NC é que a sua estruturação proporciona que organizações de manufatura venham a compartilhar informações de maneira transparente via Internet. Tendo em vista o contexto acima, no presente trabalho foi desenvolvido um protótipo de um sistema computacional CAD/CAPP/CAM voltado à manufatura remota de peças mecânicas de característica prismática utilizando a Internet como meio de comunicação, sendo completamente aderente ao padrão ISO 14649. No sistema desenvolvido foram disponibilizadas inúmeras features para o usuário remoto, incluindo não apenas superfícies com características prismáticas, mas também elementos curvos como fundos abaulados de cavidades. Um dos módulos do sistema verifica se a peça criada pelo usuário é válida do ponto de vista de fabricabilidade com as ferramentas disponíveis. Além disso, o sistema identifica se a peça pode ser fabricada em uma máquina de comando numérico de três eixos, e no caso de impossibilidade o sistema informa o usuário o que causou a não-fabricabilidade. Finalmente, o sistema gera automaticamente o arquivo físico no formato STEP (padrão ISO 10303 parte 21), o qual é disponibilizado para o usuário via Internet, podendo ele efetuar uma simulação gráfica dos movimentos das ferramentas usinando a peça, tendo o arquivo físico como entrada. Até o momento não foi desenvolvido nenhum sistema computacional que disponibilize tal arquivo gratuitamente na Internet, e consequentemente o sistema desenvolvido neste trabalho contribui para uma maior disseminação do padrão STEP-NC, além do fato que o arquivo gerado poderá ser utilizado em máquinas CNC reais compatíveis com o formato STEP parte 21.With the rapid advancement of information technology associated with manufacturing technology, manufacturing environments have changed significantly in recent decades. High speed machining, ultra-precision machining, and multi-axis machining have improved manufacturing productivity and quality. In addition, Internet technology has introduced e-manufacturing (i.e., designed by anyone anywhere, manufactured by anyone anywhere). The key to the success of e-manufacturing consists of compatible data stream with no gaps in the CAD-CAPP-CAM-CNC chain. Despite advances in manufacturing technologies, the language that are used by numerical control machines today (i.e. G-code - ISO 6983 standard) is still based on the movements of the end of the tools and on the machine status, causing the loss of much information about the product, making it difficult or impossible to share such information in different areas of the company. The ISO 14649 (STEP-NC) standard provides a model of high-level information about the product, such as the use of features for the modeling parts and manufacturing operations, and this standard has been recommended as a suitable tool to overcome the aforementioned problems. Thus, for a market where it is quite common the high variability of parts being produced, the change in features that compose the part is faster and easier than changing the G code for machining the part, and thus companies are enabled to respond more quickly to the change in part design, besides helping to accelerate decision-making related to the manufacture of parts. Another advantage of using STEP-NC is that its structure enables manufacturing organizations to share information seamlessly via the Internet. Given the above context, in the present research work a prototype CAD/CAPP/CAM computer system was developed for the remote manufacture of mechanical prismatic mechanical parts using the Internet as a means of communication, completely compliant with the ISO 14649 standard. In the developed system many features are provided to the remote user, including not only surfaces with prismatic features, but also curved elements like general cavities. One of the modules of the system verifies whether the part created by the user is valid from the standpoint of manufacturability with the tools available. In addition, the system identifies whether the part can be manufactured in a numerical control machine with three axes, and if that is not feasible, the system informs the user the cause of non-manufacturability. Finally, the system generates automatically the physical STEP file (ISO 10303 Part 21), which is provided to the user via the Internet, and he can perform a graphic simulation of the movement of the tools machining the part, having the physical file as input. So far no computer system was developed that provides such a file for free on the Internet, and therefore the system developed in this work contributes to a further spread of the STEP-NC standard, plus the fact that the generated file can be used in real CNC machines compatible with the STEP part 21 format