Ship product modelling

This paper is a fundamental review of ship product modeling techniques with a focus on determining the state of the art, to identify any shortcomings and propose future directions. The review addresses ship product data representations, product modeling techniques and integration issues, and life phase issues. The most significant development has been the construction of the ship Standard for the Exchange of Product Data (STEP) application protocols. However, difficulty has been observed with respect to the general uptake of the standards, in particular with the application to legacy systems, often resulting in embellishments to the standards and limiting the ability to further exchange the product data. The EXPRESS modeling language is increasingly being superseded by the extensible mark-up language (XML) as a method to map the STEP data, due to its wider support throughout the information technology industry and its more obvious structure and hierarchy. The associated XML files are, however, larger than those produced using the EXPRESS language and make further demands on the already considerable storage required for the ship product model. Seamless integration between legacy applications appears to be difficult to achieve using the current technologies, which often rely on manual interaction for the translation of files. The paper concludes with a discussion of future directions that aim to either solve or alleviate these issues

A REVIEW OF INTELLIGENT CNC CONTROLLER DEVELOPMENT BASED ON STEP-NC

In the contemporary Computer Numeric Controlled (CNC) machine tools of Computer Aided Manufacturing (CAM) and CNC process conducted by a number of inter-related operations and parameters using G Codes and M codes set as RS274 or ISO 6983 standard. However, this programming language does not explicitly relate to each other to have control of arbitrary locations other than the motion of the block-by-block. STEP-NC is the extension to STEP, Standard for Exchange Product model data. This determines the neutral data format for digital information from a product. STEP-NC standard is on how information about CNC machining can be added to parts represented in the STEP product model data. In this paper is to review and explore the making of interoperable CNC manufacturing is then provided relating milling, turning, turn-mill through the development of information models for products, processes and new machining system controller developed base on new standard ISO 14649 standard and ISO 10303, which related to data modeling for CNC features, process planning, and machine tool. It is expected that this paper will meet a step towards the requirements for global interoperable manufacturing for real-life machining system

Design of a Feature Recognition System for CAD/CAM Integration

This paper presents a methodology for implementing the feature recognition system for achieving the Computer Aided Design/ Computer Aided Manufacturing (CAD/CAM) integration goals. The Featurebased modeling is being used to model the solid models. The features being considered in this paper is hole form feature. The input of the feature recognition system is the Standard for the Exchange of Product Model Data (STEP) files. The set of feature recognition rules is generated by using ruled based technique

Development of feature recognition system for CAD/CAM integration

This paper presents a methodology for implementing the feature recognition system for achieving the Computer Aided Design/ Computer Aided Manufacturing (CAD/CAM) integration goals. The Featurebased modeling is being used to model the solid models. The features being considered in this paper is hole form feature. The input of the feature recognition system is the Standard for the Exchange of Product Model Data (STEP) files. The set of feature recognition rules is generated by using ruled based technique

Step and Step-Nc as a Tool for Big Data in Cloud Manufacturing

The terms big data, cloud manufacturing, predictive and additive manufacturing, and Internet of Things (IoT) are being most commonly used in the manufacturing industry nowadays. These terms are related to the fourth industrial revolution that emphasizes automation and data exchange between manufacturing tools/elements. Communication occurs between machines, products and even technicians or operators through various technologies while creating records of each interaction resulting in rapid growth of amount of data to be stored. Data acquisition is not a major issue since a structure or framework can properly connect these data in improving manufacturing efficiency. However, lack of effort in collecting and storing manufacturing data in the whole product life cycle process has made integration to be almost difficult to achieve. In this study, the adoption of STEP-NC method/technique was demonstrated in suiting the current explosion of big data in the industrial and manufacturing sector. The proposed methodology was developed through a study of an entity file structure and hierarchical concept in STEP and STEP-NC in gathering manufacturing data in a unified database. The challenge would be in making sense of the data, revealing the patterns in it and using them for operational improvements. The outcome of this study will be useful to support strategic decision making in product manufacturing

STEP/XML based macro data representation for parametric CAD model exchange

There is tremendous need in collaborative design today for the integration of heterogeneous CAx systems. This general practice has serious shortcomings like design discontinuity, limited parallelisation, loss of information, and conversion errors. To overcome these shortcomings, macro-parametric approach (MPA), which is a history-based method of parametric CAD model exchange, has been proposed. The macro-parametric approach is a way to achieve compatible CAD model exchange amongst a variety of mutually incompatible CAD systems. CAD models can be exchanged in the form of a macro file that comprises a sequence of modeling commands. A standard macro file that contains a set of event-driven commands can transfer the designer intent such as parameters, features and constraints. Currently, STEP (STandard for the Exchange of Product model data) as an international standard (ISO-10303, Industrial automation systems and integration - Product data representation and exchange) for the computer-interpretable representation and the exchange of product model data is widely used. STEP is becoming the 'lingua franca' in the area of modelling and exchanging product data. One remaining problem of the using STEP as a neutral format is that it does not retain parametric information such as the designer intent but only the pure boundary representation (B-rep) of the CAD model. The B-rep model without parametric information presents difficulties for engineering changes and it may also lead to an unexpected distortion of shape. This research aims to investigate an exchange method that uses STEP/XML (extensible mark-up) technology to express a set of standard modeling commands extracted from CAD models created by Autodesk InventorTM, to enable the same CAD models are readable and shareable with other CAD application systems

Product Policy and the East-West Productivity Gap: Evidence from German Manufacturing Firms

After 20 years of transition from an economy integrated in an exchange scheme of planned economies towards an open market economy based on the ideas of competition, we ask whether East German firms succeeded in finding their place in the international division of labour. We concentrate on the question, to what extent they have caught up with the productivity level of their Western counterparts of similar size and sector and how this productivity difference is related to changes in their product policy. We analyse these questions with a unique data set provided by Statistics Germany that contains both product policy and productivity information for individual manufacturers from both parts of the country. Using a decomposition approach suggested by Nopo (2008) as a nonparametric extension of the widely-used Oaxaca-Blinder methodology (Blinder 1973; Oaxaca 1973) we find that the time span from 1995 - 2004 has two component periods: a period of adaptation from 1995 to 2001and a period of branding from 2002 to 2004. The initial period is characterized by a smaller share of Eastern firms that modify their product range and by a large productivity gap of Eastern Non-Modifiers if compared to Western Non-Modifiers of comparable size and sector. The evidence for the second period, however, points to a more active and established role of East German manufacturers: more of them alter their product range and step up their productivity performance.Productivity, product policy, decomposition, transition economies

Product policy and the East-West productivity gap

After 20 years of transition from an economy integrated in an exchange scheme of planned economies towards an open market economy based on the ideas of competition, we ask whether East German firms succeeded in finding their place in the international division of labour. We concentrate on the question, to what extent they have caught up with the productivity level of their Western counterparts of similar size and sector and how this productivity difference is related to changes in their product policy. We analyse these questions with a unique data set provided by Statistics Germany that contains both product policy and productivity information for individual manufacturers from both parts of the country. Using a decomposition approach suggested by Nopo (2008) as a nonparametric extension of the widely-used Oaxaca-Blinder methodology (Blinder 1973; Oaxaca 1973) we find that the time span from 1995-2004 has two component periods: a period of adaptation from 1995 to 2001and a period of branding from 2002 to 2004. The initial period is characterized by a smaller share of Eastern firms that modify their product range and by a large productivity gap of Eastern non-modifiers if compared to Western non-modifiers of comparable size and sector. The evidence for the second period, however, points to a more active and established role of East German manufacturers: more of them alter their product range and step up their productivity performance.Productivity, Product Policy, Decomposition, Transition Economies