An Integrated Intelligent CAD/CAPP Platform: Part I-Product Design Based on Elementary Machining Features

We present a platform for integrated CAD/CAPP part design based on Elementary Machining Features (EMF) and intelligent approach for setup planning and operation sequencing based on a genetic algorithm through two papers. In this paper, as Part I of this platform, CAD design is executed by destructive method using objects in the form of EMF. We developed this platform based on EMF in the form of extension of the SolidWorks program system, based on Application Programming Interface (API). Also, completely new informational structure of the EMF`s, database and management of the database of the EMF`s were developed. During design phase, child EMF (generated via parent EMF from database) was enriched with a wide range of technological information. Production rules, based on the existing (geometrical) and additional (technological) information generated from the EMF, were developed and further used to generate a list of elementary machining operations (EMO) for each EMF. All previously mentioned pieces of information were necessary in the later phase of the proposed platform which was described in Part II of this paper. In this paper we present a case study applied to one new industrial example-body of the hydraulic cylinder, confirming a high level of usability of this part of integrated intelligent platform

Industry 4.0 and New Paradigms in the Field of Metal Forming

Over the last few year, the metalworking sector has been undergoing rapid and radical transformations driven by global competition and the revision of the production focus that is being moved from mass customization to mass individualization. A results of this is introduction of new manufacturing strategies such as Industry 4.0, a concept that combines cyber-physical systems and promote communication and connectivity. Therefore, this concept changes not only the face of the manufacturing systems but also causes transformation of existing business models and the society as a whole. This paper deals with the recent trends and paradigms in the field of metal forming, resulting from the concept of Industry 4.0 and the modern market challenges. The maim attention is paid on the flexibility of manufacturing systems and recent developments in design of smart forming tools

A model of collaborative process planning system (e-CAPP)

Današnja tendencija globalne konkurentnosti zahtijeva razvoj distribuiranih aplikacionih sustava koji se koriste u projektiranju proizvoda, pripremi proizvodnje, kao i izravno u procesu proizvodnje. Na ovaj način se stvaraju distribuirana projektantska i proizvodna okruženja koja nadilaze tradicionalna fizička i vremenska ograničenja. Primjenom Internet/intranet tehnologije povezuju se i integriraju geografski dislocirani projektanti, eksperti, sustavi, resursi i servisi. Analizom novih tendencija u planiranju i pripremi distribuirane proizvodnje uočena je potreba za razvojem kolaborativnog sustava u oblasti projektiranja tehnoloških procesa. Aktivnosti vezane za projektiranje tehnoloških procesa izrade se u distribuiranim okruženjima često realiziraju primjenom proširenog CAPP sustava čija je baza znanja proširena i unaprijeđena znanjem dislociranih eksperata. e-CAPP upravo predstavlja jedan takav kolaborativni sustav namijenjen projektiranju tehnoloških procesa izrade proizvoda.The current tendency of global competitiveness requires the development of distributed application systems that are used in the product design, the production preparation, as well as directly in the manufacturing processes. In this way, distributed design and production environments created actually exceed traditional physical and time constraints. The application of internet/intranet technologies enables the connection and integration of geographically dislocated designers, experts, systems, resources and services. After analysing new tendencies in planning and preparing the distributed manufacturing, a need to develop a collaborative system in the area of process planning is identified. Activities related to process planning in distributed environments are often realized by applying the extended CAPP system whose knowledge base is increased and improved by the knowledge of geographically dislocated experts. The e-CAPP represents exactly such a collaborative system which can be effectively applied in the area of process planning

APPLYING PRECEDENCE RELATIONSHIPS AND CAD/CAM SIMULATION IN TIME-BASED OPTIMIZATION OF PROCESS PLANNING

Optimization of process planning belongs to the group of combinatorial optimization problems which at the macro and micro level consists of the selection of machining operations, definition of sequences of machining operations and their grouping into processes, selection of manufacturing resources, machining parameters and strategies. The objective function used for evaluating process plans is mostly defined by manufacturing cost, manufacturing time, surface quality and surface accuracy. The main goal of this research refers to the process planning and optimization of manufacturing time by applying precedence relationships among machining operations, as well as the simulation technique within the CAD/CAM system. The precedence relationships are defined on the basis of dimensional, geometric, technological and economical precedence constraints. Based on these rules, precedence matrices for determining operation sequence for the given shaft part are formed, and afterwards, machining operations are grouped into appropriate processes. For the given rational variants of process plans, a simulation of machining process is performed within the Catia software system. The obtained output is the best variant of process plan for the shaft part on the basis of manufacturing time as the adopted objective function

A model of tool wear monitoring system for turning

Prikupljanje kvalitetnih i pravovremenih informacija o stanju alata u realnom vremenu predstavlja nužan uvjet za identifikaciju stupnja istrošenosti alata čime se u značajnoj mjeri poboljšava postojanost i kvaliteta procesa obrade. Ovaj rad se bavi definiranjem modela sustava za klasifikaciju istrošenosti alata uz poseban osvrt na modul za prikupljanje i obradu signala ubrzanja vibracija primjenom diskretnih "wavelet" transformacija (DWT) pri dekomponiranju signala. U radu je prikazan model razvijenog fuzzy sustava za klasifikaciju trošenja alata. Sustav sačinjavaju tri podsustava: za prikupljanje i obradu podataka, za klasifikaciju istrošenosti alata i odlučivanje. U okviru podsustava za prikupljanje i obradu podataka prikazana je izabrana metoda izdvajanja značajki. U okviru klasifikacije i grupiranja podataka prikazan je izabrani model fuzzy klasifikatora i provjera klasifikacije u eksperimentalnim laboratorijskim uvjetima. Primijenjeni model testiran je za zahvate uzdužne i poprečne obrade.Acquiring high-quality and timely information on the tool wear condition in real time, presents a necessary prerequisite for identification of tool wear degree, which significantly improves the stability and quality of the machining process. Defined in this paper is a model of tool wear monitoring system with special emphasis on the module for acquisition and processing of vibration acceleration signal by applying discrete wavelet transformations (DWT) in signal decomposition. The paper presents a model of the developed fuzzy system for tool wear classification. The system comprises three modules: module for data acquisition and processing, module for tool wear classification, and module for decision-making. The selected method for feature extraction is presented within the module for data classification and processing. The selected model for the fuzzy classifier and classification in experimental laboratory conditions is shown within data classification and clustering. The proposed model has been tested in longitudinal and transversal machining operations

A model of tool wear monitoring system for turning

Prikupljanje kvalitetnih i pravovremenih informacija o stanju alata u realnom vremenu predstavlja nužan uvjet za identifikaciju stupnja istrošenosti alata čime se u značajnoj mjeri poboljšava postojanost i kvaliteta procesa obrade. Ovaj rad se bavi definiranjem modela sustava za klasifikaciju istrošenosti alata uz poseban osvrt na modul za prikupljanje i obradu signala ubrzanja vibracija primjenom diskretnih "wavelet" transformacija (DWT) pri dekomponiranju signala. U radu je prikazan model razvijenog fuzzy sustava za klasifikaciju trošenja alata. Sustav sačinjavaju tri podsustava: za prikupljanje i obradu podataka, za klasifikaciju istrošenosti alata i odlučivanje. U okviru podsustava za prikupljanje i obradu podataka prikazana je izabrana metoda izdvajanja značajki. U okviru klasifikacije i grupiranja podataka prikazan je izabrani model fuzzy klasifikatora i provjera klasifikacije u eksperimentalnim laboratorijskim uvjetima. Primijenjeni model testiran je za zahvate uzdužne i poprečne obrade.Acquiring high-quality and timely information on the tool wear condition in real time, presents a necessary prerequisite for identification of tool wear degree, which significantly improves the stability and quality of the machining process. Defined in this paper is a model of tool wear monitoring system with special emphasis on the module for acquisition and processing of vibration acceleration signal by applying discrete wavelet transformations (DWT) in signal decomposition. The paper presents a model of the developed fuzzy system for tool wear classification. The system comprises three modules: module for data acquisition and processing, module for tool wear classification, and module for decision-making. The selected method for feature extraction is presented within the module for data classification and processing. The selected model for the fuzzy classifier and classification in experimental laboratory conditions is shown within data classification and clustering. The proposed model has been tested in longitudinal and transversal machining operations

A hybrid grey wolf optimizer for process planning optimization with precedence constraints

Process planning optimization is a well-known NP-hard combinatorial problem extensively studied in the scientific community. Its main components include operation sequencing, selection of manufacturing resources and determination of appropriate setup plans. These problems require metaheuristic-based approaches in order to be effectively and efficiently solved. Therefore, to optimize the complex process planning problem, a novel hybrid grey wolf optimizer (HGWO) is proposed. The traditional grey wolf optimizer (GWO) is improved by employing genetic strategies such as selection, crossover and mutation which enhance global search abilities and convergence of the traditional GWO. Precedence relationships among machining operations are taken into account and precedence constraints are modeled using operation precedence graphs and adjacency matrices. Constraint handling heuristic procedure is adopted to move infeasible solutions to a feasible domain. Minimization of the total weighted machining cost of a process plan is adopted as the objective and three experimental studies that consider three different prismatic parts are conducted. Comparative analysis of the obtained cost values, as well as the convergence analysis, are performed and the HGWO approach demonstrated effectiveness and flexibility in finding optimal and near-optimal process plans. On the other side, comparative analysis of computational times and execution times of certain MATLAB functions showed that the HGWO have good time efficiency but limited since it requires more time compared to considered hybrid and traditional algorithms. Potential directions to improving efficiency and performances of the proposed approach are given in conclusions.Web of Science1423art. no. 736

Application of STEP-NC in the integration CAX and CNC systems: Case studies

The paper describes possibility of implementation the STEP-NC in process planning for CNC machining, and integration of CAx and CNC systems. Proposed are two variants of possible applying, with verification on example. As software for the realization of CAD/CAM activities were used Pro/E and Catia, while for generate STEP-NC programs and management information to process used software STEP-NC Machine

Application of STEP-NC in the integration CAX and CNC systems: Case studies

The paper describes possibility of implementation the STEP-NC in process planning for CNC machining, and integration of CAx and CNC systems. Proposed are two variants of possible applying, with verification on example. As software for the realization of CAD/CAM activities were used Pro/E and Catia, while for generate STEP-NC programs and management information to process used software STEP-NC Machine

A grey fuzzy approach to the selection of cutting process from the aspect of technological parameters

This study deals with the selection of the cutting process using the grey fuzzy relation approach. The analysis was performed using plasma arc machining, laser beam machining, and abrasive waterjet machining on three different workpiece thicknesses with different cutting speeds. The objective was to select the best cutting process considering several performance characteristics such as machining time, dimensional accuracy, kerf width, and surface roughness. Data normalization, grey relation coefficients, fuzzy inference system, and grey fuzzy relation grade are used to evaluate the machining performances of the machining processes. The developed fuzzy model can be used to study the effects of different cutting processes on technological features. The results show that the grey fuzzy technique can be effectively used for the analysis and selection of cutting processes.Web of Science1224art. no. 1258