Functional architecture and specifications for Tolerancing Data and Knowledge Management

Part 1: Knowledge ManagementInternational audienceThe paper deals with the Computer-Aided Tolerancing and Product Data Management. It is especially focus on data and knowledge management system to support and improve the tolerancing tasks in product development process. The first part of the paper introduces an overview about the recent developments related to tolerancing supports and data management systems. Based on a literature survey and industrial issues, the second part proposes a functional architecture and specifications of the data and knowledge manage-ment system addressing the numerous needs clarified by tolerancing experts

Virtual manufacturing: prediction of work piece geometric quality by considering machine and set-up

Lien vers la version éditeur: http://www.tandfonline.com/doi/full/10.1080/0951192X.2011.569952#.U4yZIHeqP3UIn the context of concurrent engineering, the design of the parts, the production planning and the manufacturing facility must be considered simultaneously. The design and development cycle can thus be reduced as manufacturing constraints are taken into account as early as possible. Thus, the design phase takes into account the manufacturing constraints as the customer requirements; more these constraints must not restrict the creativity of design. Also to facilitate the choice of the most suitable system for a specific process, Virtual Manufacturing is supplemented with developments of numerical computations (Altintas et al. 2005, Bianchi et al. 1996) in order to compare at low cost several solutions developed with several hypothesis without manufacturing of prototypes. In this context, the authors want to predict the work piece geometric more accurately by considering machine defects and work piece set-up, through the use of process simulation. A particular case study based on a 3 axis milling machine will be used here to illustrate the authors’ point of view. This study focuses on the following geometric defects: machine geometric errors, work piece positioning errors due to fixture system and part accuracy

DFM synthesis approach based on product-process interface modelling. Application to the peen forming process.

Engineering design approach are curently CAD-centred design process. Manufacturing information is selected and assessed very late in the design process and above all as a reactive task instead of being proactive to lead the design choices. DFM appraoches are therefore assesment methods that compare several design alternatives and not real design approaches at all. Main added value of this research work concerns the use of a product-process interface model to jointly manage both the product and the manufacturing data in a proactive DFM way. The DFM synthesis approach and the interface model are presented via the description of the DFM software platform

Specifications and Development of Interoperability Solution dedicated to Multiple Expertise Collaboration in a Design Framework

This paper describes the specifications of an interoperability platform based on the PPO (Product Process Organization) model developed by the French community IPPOP in the context of collaborative and innovative design. By using PPO model as a reference, this work aims to connect together heterogonous tools used by experts easing data and information exchanges. After underlining the growing needs of collaborative design process, this paper focuses on interoperability concept by describing current solutions and their limits. Then a solution based on the flexibility of the PPO model adapted to the philosophy of interoperability is proposed. To illustrate these concepts, several examples are more particularly described (robustness analysis, CAD and Product Lifecycle Management systems connections)

On Knowledge-based Development: How Documentation Practice Represents a Strategy for Closing Tolerance Engineering Loops

AbstractKnowledge from multiple sources is required for defining tolerances in new product development (NPD). Successful outcomes in product development (PD) depend on the collective ability to integrate this knowledge into the product. Assessing variability and tolerance capabilities are essential parts of PD-knowledge as they represent limits of specifications with wide-ranging impact. Reducing the engineers time spend on (re)defining tolerances and searching for the right information can prevent substandard NPD performance in terms of quality, lead time, cost and product innovation. Hence, two topics of significant importance for achieving leanness (i.e., effectiveness and efficiency) in PD are towering tolerance knowledge and associated documentation practices. This paper presents the results of a survey among engineering professionals of two industrial companies made to study documentation and tolerance practices in different industrial environments. The results reveal similarities between the challenges that the companies face, including implementation of effective documentation (e.g. Knowledge-Briefs, A3 reports), visualization of physical relationship between product performance attributes and design parameters (e.g. trade-off curves) and the transfer of knowledge between projects for organizational learning. This paper makes a contribution to the body of knowledge related to (lean) NPD by documenting current industrial challenges and practices in achieving viable internal tolerance engineering routines and processes, along with the needs for documentation tools

Review of research in feature-based design

Research in feature-based design is reviewed. Feature-based design is regarded as a key factor towards CAD/CAPP integration from a process planning point of view. From a design point of view, feature-based design offers possibilities for supporting the design process better than current CAD systems do. The evolution of feature definitions is briefly discussed. Features and their role in the design process and as representatives of design-objects and design-object knowledge are discussed. The main research issues related to feature-based design are outlined. These are: feature representation, features and tolerances, feature validation, multiple viewpoints towards features, features and standardization, and features and languages. An overview of some academic feature-based design systems is provided. Future research issues in feature-based design are outlined. The conclusion is that feature-based design is still in its infancy, and that more research is needed for a better support of the design process and better integration with manufacturing, although major advances have already been made

Efficiency improvement of product definition and verification through Product Lifecycle Management

The correct and complete geometrical definition of a product is nowadays a critical activity for most companies. To solve this problem, ISO has launched the GPS, Geometrical Product Specifications and Verification, with the goal of consistently and completely describe the geometric characteristics of the products. With this project, it is possible to define a language of communication between the various stages of the product lifecycle based on "operators": these are an ordered set of mathematical operations used for the definition of the products. However, these theoretical and mathematical concepts require a level of detail and completeness of the information hardly used in usual industrial activities. Consequently in industrial practice the definition and verification of products appears to be a slow process, error-prone and difficult to control. Product Lifecycle Management (PLM) is the activity of managing the company's products throughout their lifecycle in the most efficient way. PLM describes the engineering aspects of the products, ensuring the integrity of product definition, the automatic update of the product information and then aiding the product to fulfil with international standards. Despite all these benefits, the concepts of PLM are not yet fully understood in industry and they are difficult to implement for SME's. A first objective of this research is to develop a model to depict and understand processes. This representation is used as a tool during the application of a case study of a whole set of a GPS standards for one type of tolerance. This procedure allows the introduction of the GPS principles and facilitates its implementation within a PLM process. Until now, PLM is presented on isolated aspects without the necessary holistic approach. Furthermore, industry needs people able to operate in PLM context, professional profiles that are not common on the market. There is therefore an educational problem; besides the technical knowledge, the new profile of engineers must be also familiar with the PLM philosophy and instruments to work effectively in a team. With the aim of solving this problem, this thesis presents a PLM solution that gives the guidelines for a correct understanding of these topic

Automated Point-based Tolerance Analysis Model Creation for Sheet Metal Parts

AbstractThis paper focuses on a concept that shows a way to automatically create a point-based tolerance analysis model out of existing development data. Nowadays solutions for an automated tolerance simulation model creation are using a static approach for the model build-up. For this purpose product-/ production- development data are automatically mapped on preexisting models (e.g. skeleton models). If chances during development process occur, the tolerance simulation models have to be reworked. Today only simple changes in the model can be automated (e.g. change of distribution, tolerance range etc.). A complete new tolerance simulation model build-up process for dynamically changing product-/ production- development information is not possible. To give an application example, tolerance simulation models for sheet metal parts in automotive industry are based on different development data. Before the first simulation model is created (to secure the tolerance concepts etc.), all necessary information have already been developed, e.g. in the automotive industry's development process: part geometry, tolerance information, assembly graph, jig and fixture concept, joining location and measurement points. Thus the automated simulation generation should be possible.First step is to describe an interface for a dynamic model creation in tolerance simulation systems. In a second step preprocessing of development data is necessary to map them into tolerance simulation software restrictions. This delivers a solution to fill the gap between the PDM-/ CAD and the CAT-system. The considered approach for automated tolerance simulation model creation provides the opportunity to build-up the tolerance analysis models highly efficient and almost automatically. Tolerance analysis can then be used to rapidly calculate several options. This offers the possibility to increase the product maturity level at a very early stage of the development process

Critical Review of Tolerance Management in Construction

The current practice of Tolerance Management (TM) is still very ad hoc and reactive, despite increasing calls for waste reduction and an improved quality of buildings particularly within industrialised construction. This paper aims to identify the root causes of tolerance problems, the reasons why current methods have not been as successful as expected and why the industry still struggles with this issue. Having reviewed and interpreted the existing literature, it is apparent that tolerance problems fall into two categories defined by intrinsic and extrinsic factors. Furthermore, the drawbacks of the existing methods for TM were analysed, and the findings show that none of the existing methods have been considered in a continuous and holistic process and they remain scattered

Project SPACE: Solar Panel Automated Cleaning Environment

The goal of Project SPACE is to create an automated solar panel cleaner that will address the adverse impact of soiling on commercial photovoltaic cells. Specifically, we hoped to create a device that increases the maximum power output of a soiled panel by 10% (recovering the amount of power lost) while still costing under $500 and operating for up to 7.0 years. A successful design should operate without the use of water. This will help solar panel arrays achieve a production output closer to their maximum potential and save companies on costs associated energy generation. The current apparatus utilizes a brush cleaning system that cleans on set cleaning cycles. The device uses the combination of a gear train (with 48 pitch Delrin gears) and a 12V DC motor to spin both a 5.00 foot long, 0.25 inch diameter vacuum brush shaft and drive two sets of two wheels. The power source for the drive train is a 12V deep cycle lead-acid battery. Our light weight design eliminates water usage during cleaning and reduces the potential dangers stemming from manual labor. Our design’s retail price was estimated to be around$700 with a payback period of less than 3.5 years. To date, we have created a device that improves the efficiency of soiled solar panels by 3.5% after two runs over the solar panel. We hope that our final design will continue to expand the growth of solar energy globally