Papers by Keyword: CAPP

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Authors: R.K. Abdel-Magied, H.M.A. Hussein
Abstract: The aim of this work is to develop an integrated system for facilitating the process of designing the drawing dies and their component. The developed system is based on the integration between Computer Aided Process Planning in Sheet Metal Drawn parts “CAPP”, and the Computer Aided Design in Deep Drawing Die components “CAD”. Both modules are coded using Visual Basic program and joined with AutoCAD. The CAPP module made to report the drawing load and to plot the shape of the drawn shell in each stage of the Axis-Symmetric Deep Drawing process. Based on the reported shell geometry, the dimensions of the die components are calculated and transferred to the CAD module. The CAD module, which is based on many data bases (standard parts, sheet metal data), plots the required deep drawing die components for each drawn stage on the AutoCAD monitor. A demonstrated example is presented to validate the developed system and to show that the system results are acceptable.
Authors: T.H.M. Nguyen, Joost R. Duflou, Jean Pierre Kruth
Abstract: Sheet metal bending is a metal forming process, in which flat sheets are bent along straight bend lines in a specific bending sequence to form three-dimensional parts. A large number of tools with different characteristics can be used in this process. The task to choose the right tooling for a requested sheet metal part is however one of the bottle necks in process planning. An inefficient tool selection may result in failure of finding a feasible bending sequence. In previous work, methodologies for tool selection and optimization have been proposed. The presented paper describes a framework to implement these methodologies into a system that allows automatic tool selection in consistent consideration of bend sequencing. As a result, automated and optimized tool selection for sheet metal bending is achieved, as illustrated by performance test results for a robust software implementation.
Authors: Cezary Grabowik, Krzysztof Kalinowski, Wojciech Kempa, Iwona Paprocka
Abstract: The proposed idea of the integration methodology is based on the two basic pillars it is the modified functional model of the manufacturing process plan and a product intermediate states representation. The product state in certain moment of the manufacturing process can be identified by a set of states which describe the current status of the manufacturing process advance for particular manufacturing features. On the other hand from a manufacturing process nature results that during its course a product can be at one of the following states after rough, medium and finishing manufacturing treatment. Information about product states makes the full integration between CAPP and CAP systems possible. The proposed methodology allows reacting to unexpected production process disturbances. In this case the CAP system in cooperation with manufacturing execution system MES, which collects production data just from PLCs controllers, communicates with CAPP system in the feedback loop and sends a set of the product intermediate states. Base on this description the CAPP system redesign a manufacturing process plan taking into account the current product state. In the paper the modified functional model of the technological process plan and the method of product intermediate states are presented. Moreover the proposal of the functional schema of the integrated CAD/CAPP/CAP environment is shown.
Authors: Cezary Grabowik, Rafał Zbiciak
Abstract: Problems of design similarity identification and elements grouping play a key factor in the development of design standardization and the group technology methods. Design similarity identification methods are most often based on a comparison of codes ascribed to products design. Basically the code makes a quantitative product description including different product features. Whereas a qualitative description has constituted rather supplement of a quantitative description. The most important issue in a process of design similarity identification is a method of a product design description. This description is usually made with use of special codes composed of alphanumeric characters. The coding process allows reducing the number of data which are being processed during design similarity evaluation, but on the other hand in some cases it could cause information loss. Taking into account above there is still a need of working out of a new method of a product design description which will be able to reduce these negative features of coding techniques. In the paper a novel approach for a product design description is presented. It is proposed to apply a hybrid method for a design representation purpose. This method uses a combination of code chains for a product longitudinal cross-section representation and a spatial matrix for transvers sections. As a result of the conducted research a new method of a product design description was worked out. This method is especially suggested for application in automatic design feature recognition systems (AFR systems) in which a design feature database (DFD) is present.
Authors: Cezary Grabowik, Krzysztof Kalinowski, Wojciech M. Kempa, Iwona Paprocka
Abstract: Process planning is one of the most important links in planning of the manufacturing system functioning, it coordinates and integrates processes planners, designers and economists intentions. The main goal to reach during the process planning phase is to determine the process plan structure it is manufacturing operations and cuts which have to be applied in order to transform given semifinished product into a product with the strict determined design and properties. Simultaneously process planers strive for working out such a process plan which satisfies criteria of the lowest manufacturing cost and labour consumption taking into account current accessibility of manufacturing resources. Process planning is still one of the most difficult, complex and time consuming process planner activities. Traditionally the process plan is designed with so-called manual method. During process planning with this method a process planner is forced to analyse the sequence of manufacturing cuts and operations in the process plan structure and also to analyse alternative processes taking into consideration achieving as low as possible unit manufacturing cost. In this case the process plan quality in principle depends exclusively on process planner knowledge and skills. Taking into account above the methods of process planning functions automation are searched. This goal can be reached by application of computer tools. Computer methods of process planning went through the long evolution process and their development is characterized by the following features: decreasing of process planner participation in the planning of the base structure of process plan, broad application of technological databases, broad application of technological knowledge bases, and possibilities of cooperation with commercial CAD/CAM/CAE systems [1,. In this paper the detailed information on methods of computer aided process planning are given. The variant, semi generative and generative methods are discussed. The main merits and drawbacks for each method are shown.
Authors: Cezary Grabowik, Krzysztof Kalinowski, Iwona Paprocka, Wojciech Kempa
Abstract: The need of integration of all engineering activities starting from a designing stage finishing on manufacturing implies the necessity of application of a new software solution. Among them CAPP systems seem to be the best and the most promising integration tool. There are the two basic methods of the computer aided process planning it is the variant and generative methods. These CAPP modelling methods are based on the different principles. The variant method is based, in general, on the ideas of the design similarity and group technology whilst the generative one mainly on the basis of utilization of the manufacturing knowledge store and the automatic process synthesis. It is a well-known fact that the variant process planning approach is based on the hypothesis that similar parts would have similar process plans. In a CAPP variant process planning system it is necessary to look for similarities between parts. Process plans formerly prepared and stored in the CAPP system manufacturing database are used for planning of new manufacturing processes for new parts similar to those recorded in system database. In the variant system working out of the classification schema and similarity measures is essential. In this paper an attempt to application of chain codes for a design similarity evaluation is presented. The proposed procedure is based on application of the chain codes for description of the parts selected longitudinal cross sections. The proposed chain code structure is created in similar way to this used for the Freeman code formation but unlike classic Freeman chain code the parts cross section is discretized in more than the 8 cardinal directions. The characteristic feature of the proposed profile coding method is the approach for the code starting point selection. In each case the part design chain code is created starting from the a priori selected upper left corner of a product. The idea of products similarity evaluation bases on the parts profile codes and application of the minimum edit distance definitions. In the paper the Levenshtein and Hamming distance for code chains similarity comparison are proposed At the current stage of research this method is used for similarity evaluation of rotational symmetric parts. The choice of the minimum edit distance measure in the proposed solution depends on product pins number.
Authors: Li Li Meng, Chun Guang Lu, Hui Zhen Zhao
Abstract: The traditional CAPP system pays much attention to the intelligent generation of the parts process route or pursuit integration of CAD and CAPP and CAM, but it has exposed many shortcomings in the process management of process design and approval. In order to solve the problem of information transmission and process reengineering, this paper discusses the application of work flow technology in the CAPP system, and analyzes the process design and approval process based on Petri Nets model, and finally explains database design and realization of process workflow and the control mechanism of workflow engine based on state transition on emphases. Through the practical application, the system can greatly improve the efficiency of design and management of process, the process design is more flexible and more standardization.
Authors: Xiu Lin Sui, Qing Wang, Ru Yang, Qian Wang
Abstract: In order to realize high efficiency and high integration of the virtual manufacturing system and strengthen the integration of CAD/CAPP/CAM, the paper presents the architecture of virtual manufacturing oriented CAPP system and its realizing method. The method of parts information input is used for the system to connect with CAD directly. The system utilizes object-oriented knowledge representation method and database technology, establishes process knowledge database and carries on the effective management. Using the idea of modular, the virtual processing information can be fed back to design system in real-time, the process can be optimized it and form a closed loop CAPP system by using genetic algorithm. The virtual manufacturing technology of CAPP system enhances the design level and quality and improves the flexibility, scalability and dynamic adaptability of CAPP system.
Authors: Yusuke Narabu, Jiang Zhu, Tomohisa Tanaka, Yoshio Saito
Abstract: Currently CAD/CAM systems have become more common in automated manufacturing to enhance accuracy and efficiency. However, machining efficiency and accuracy are mainly relied on the experience of the engineer. Therefore, in this research the main aim is to propose the system which automatically analyzes the characteristics of a CAD model and to extract manufacturing features. The method for analyzing shapes of a CAD model represented by triangle mesh is studied. The system can extract planar, spherical, cylindrical, hole, arc, and other curved regions. This research will improve the integration of CAD, CAM system, and is supposed to have a great potential in the application of manufacturing and other engineering fields.
Authors: Xu Zhang, Chao Liang, Wei Yu Li
Abstract: In process planning of machined part, three-dimensional process intermediate models are necessary for process design, documentation, and downstream applications including clamping design, NC programing, and process analysis. An automatic process intermediate model generation method is proposed in this paper for machined part represented in B-Rep solid model. Machining features are recognized and classified according to process type. Process plan is expressed in terms of machining features and feature surface modification operations in solid model. Local modification operations are applied to part model to move, replace or remove feature surface resembling machining process. Process intermediate models are generated automatically in a batch manner by applying geometry and topology modification operations directly on B-Rep model for each machining operation. The proposed algorithm is implemented in a CAPP tool developed in solid modeler ACIS.
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