Product design and engineering

The use of recycled materials reduces the need for primary materials and it also minimizes the amount of waste in the production process. Therefore, by using recycled materials, the total material flow necessary for the production of a product can be reduced. Moreover, the total consumption of resources for the production of recycled material is, usually, remarkably inferior that in the production of the same amount of primary material. The purpose of this study is to validate this concept in the injection-moulding field using the Life Cycle Assessment (LCA) methodology. LCA quantifies and evaluates the environmental impacts of a product from the extraction of raw materials, through manufacture and use, to final disposal. Today, most people involved in the industrial engineering community (consultants, manufacturers, researchers and institutional actors) assert that Life Cycle Assessment (LCA) is one of the most successful tool to assess environmental considerations in the product design process. The main goal of this research work is to support the design decision-making process and quantify the resources saving of the use of a post consumer material instead of a primary one in the development process of the injection moulded products. The material object of this study is the Polyethylene Terephthalate (PET). In particular the test case is about the life cycle assessment of a PET clotheshorse, developed in collaboration with a SME Italian company. Traditionally the clotheshorses are made of Polypropylene (PP) or other metallic material, the purpose of this is to compare the traditional solution with the use of recycled PET for the clotheshorse production. The result of this study validates the assumption that the use of recycled material is a more environmental friendly practise and the use of the LCA methodology permitted to quantifies this environmental advantage.

Keywords: Eco-design , Injection moulding , LCA , Recycled PET

The aim of this work is an efficient methodology development for a real-time control of human assembling sequences of mechanical components. The method involves a CAD environment, an hardware system, referred to as a PAA (Personal Active Assistant), and a set of Mixed Reality features. The whole scheme is targeted to positively influence the connection between CAD and Mixed Reality in order to proficiently reduce the gap between engineers and manual operators. The system is based on a CAD assembly module and on an Mixed Reality wearable equipment. It can be used to improve several activities in the industrial field, such as operator professional training, optimal assembly sequence seeking or on-field teleconferencing (suitable for remote collaboration or for full exploitation of Concurrent Engineering suggestions during design and set up stages). The main characteristic of PAA is a real-time wireless linkage to a remote server or designer workstation, where project geometric database is stored. The Mixed Reality wearable equipment consists of an optical see-through display device and a PAA head-mounted camera. The user can freely operate in the mixed environment, while the camera can record the human driven assembly sequence and check the efficiency and correctness via object recognition: an incrementally sub-assembly detection algorithm has been developed in order to achieve complex dataset monitoring. Conversely, designer or assembly planner can exploit the peculiarities of Mixed Reality-based assembly: a straightforward interaction with the assembly operator can be obtained by sending vocal advices or by displaying superimposed visual information on the real scene. In the paper a new method for CAD models and Mixed Reality environment integration will be presented and discussed in order to improve and simplify personnel training or warehouse part seeking. © 2006 - IOS Press and the auther(s). All rights reserved.

Keywords: Assembly , CAD , Concurrent engineering , Mixed reality

Recently much interest has been devoted to novel distributed approaches which lead to the formation of collaborative networked organizations, e.g. virtual organizations, specifically oriented to generate an innovative product concept. Making use of logical-formal structures based on concepts related to directed hypergraphs, we formally represent competitive inter-organization and collaborative intra-organization relationships. Thanks to these structures, models for distributed processes which lead to the emergence of both design chains and functional architectures of an innovative product are formally described and then illustrated through examples from an applicative scenario.

Recently, the manufacturing business is moving from an economy of scale to an economy of scope, under global competition for customers' satisfaction. Under those conditions, for companies around the world, surviving in business means to satisfy at least three challenges: granting the on-duty performance, at the point-of-service; addressing value-added intangibles; and lowering life-cycle eco impact. These changes in industry reflect on the human society; they are driven both through economical and political measures, as well as being increasingly affected by ecological constraints. Servicing and recovering become challenging demands. Besides technical aspects, the emphasis is in enabling economic profits on the supply chain (by new businesses in maintenance, remanufacturing, etc.), with account of legal acts (suppliers responsibility, landfill regulation, etc.), ruled by voluntary agreements or by compulsory targets frames. Our emphasis is on the following new paradigms: extended virtual enterprise and extended product, service engineering, life-cycle engineering, product life-cycle management, proactive maintenance, recovery, reuse, recycling, ubiquitous computing and communication, and so forth. © 2007, Idea Group Inc.

The paper addresses the flexible assembly and disassembly of electromechanical products in white industry. The work is in the frame of a research project on modular assembly systems for innovative production systems. For the assembly and disassembly of washing-machine components, instead of a sequence of dedicated stations with specialized grippers designed for each component, the alternative solution of high degree-of-freedom assembly cells using reconfigurable grippers for components holding and handling is investigated. A low-cost, multifunctional adaptable gripper for handling cylindrical and prismatic shaped parts within dimensional ranges typical of the washing machines components, as provided by the industrial partner Electrolux-Zanussi, is presented and its functionalities shown and evaluated. Copyright © 2006 IFAC.

Keywords: Assembly , Automation , Design , Handling , Manipulation

The pursued goal of the present paper is to foresee modular solutions which are suitable for scale production of mobile robots for surveillance in airport indoor and outdoor areas. To this aim, a possible mechatronic modular architecture is proposed, giving details about the mechanical layout, the actuation characteristics, the power supply figures and the command-control organization. The application of quite consolidated modularity methodologies, already successfully exploited in the industrial field, offers the possibility of creating different mobile robots by the proper combinations of basic frame modules and traction/steering modules; this allows to match different requirements in terms of vehicle mobility (average speed, number of traction/steering wheels, maximum slope, etc.) and operability (payload, autonomy, type of onboard equipment, size/arrangements, etc.). Modularity, other than in the production phase, gives significant advantages during service and maintenance, reducing the MTTR and improving the overall availability. It is worthwhile noting how the outlined approach to mobile robotic systems may be effectively extended to the monitoring of similar sites, such as large squares, stock-park spots, containers districts, cars storing places, and the likes. Copyright © 2006 by ASME.

In this paper the buckling and post-buckling behaviour of unidirectional and cross-ply composite laminated plates with multiple delaminations has been studied. Finite elements analyses have been performed, using a linear buckling model, based on the solution of the eigenvalues problem, and a non-linear one, based on an incremental-iterative method. With non-linear method large displacements have been taken into account and also contact constraints between sublaminates have been added to avoid their interpenetration. It has been found that both delamination length and position and stacking sequence of the plies influence the critical load of the plate; furthermore, linear and non-linear buckling models are not always in perfect agreement. © 2005 Elsevier Ltd. All rights reserved.

Keywords: Buckling , Composite laminated plates , Composite materials , Delamination , Numerical analysis

Redesign of a product becomes necessary as a consequence of the evolution of the market requirements, of the man creativity, of the influence of the environmental factors, of the technological development etc. The redesign activity, especially in a context of exasperated economic competition, has become a crucial point in order to try to increase the competitiveness, if not even the life, of a product and/or a company. The redesign must allow the resumption of the increasing process of the performances. This aim requires a methodical and structured approach, which can also cause the modification of the standard conception of the product. In this paper the possibility to reduce the mass of a semitrailer is analysed, modifying its structure. Various solutions have been considered, characterized also by new topology and/or materials, and between all of them the one constituted from a structural floor in composite material has been chosen. © 2005 WIT Press.

Keywords: Composite material , Redesign , Semitrailer , Structural floor

This work presents a CAD prototype, named ClothAssembler, targeted at complex-shaped apparel design for real manufacturing. The intent is to fill a gap in the current CAD technology for garment design as it is mainly conceived for 2D/3D geometric modelling of cloth shapes, but generally does not provide high level operators that allow interactive and easy design of aesthetic/functional features that characterize the garment pieces, and relations/connections between parts. Though still an academic prototype, ClothAssembler allows to define/choose in an interactive way all the necessary geometric and functional information for the design and finishing of 2D pieces, such as insertion of textile layers, reinforcement lines, pockets, cut lines and pleats, as well as topological information about how pieces are pair-wise connected and assembled, by definition of seams, darts, zips, constraints such as buttons and hooks, etc. A taxonomy and parametrization of cloth tailoring features is discussed, and system functionalities are presented, with applications to garment models of real production. © 2005 by CAD Solutions Company Limited.

Keywords: CAD , Garment design , Tailoring features

In this paper the results of an experimental investigation on the effect of subcritical damage on the residual strength properties of notched composite laminates are presented. A procedure based on the digital image correlation method was applied to laminates subjected to static and fatigue tensile loading. The digital image correlation method (DICM) is a whole-field technique that calculates surface displacements and strains from digital images characterized by a random distribution of intensity grey levels. Graphite/PEEK (polyether ether ketone) and graphite/epoxy laminates with different stacking sequences were analysed and the damage progression near the stress riser was evaluated by means of the strain maps obtained by digital image correlation. It was found that damage developing before final fracture may significantly affect the structural performance of composite laminates. The digital image correlation technique allowed clarification of the beneficial or detrimental role played by the different failure mechanisms on the strain redistribution around the hole and, as a consequence, on the residual strength and fatigue life of notched samples. The findings of the investigation suggest that the DICM is an efficient and reliable tool for full-field monitoring and detailed damage characterization of structural composite elements. © IMechE 2005.

Keywords: Composite materials , Damage , Digital image correlation , Fatigue , Notch

The overall aim of this paper is to present a web-based system to simulate the process of aircraft design in a competitive environment. The main purpose is to provide a tool to introduce design and simulation problems in engineering-design education. The structure of the system is a game where a group of teams carry out the design of an aircraft trying to optimize product performances and minimizing product and development costs. The web-based framework is a three-tier system developed in a pure Java platform using the JavaServer Faces technology for the presentation layer and Hiber-nate/HSQL for the persistence layer.

Keywords: Competitive environments , Engineering education , Lean simulation , Product design , Web-based simulation

We report on the development of the LISA Technology Package (LTP) experiment that will fly onboard the LISA Pathfinder mission of the European Space Agency in 2008. We first summarize the science rationale of the experiment aimed at showing the operational feasibility of the so-called transverse-traceless coordinate frame within the accuracy needed for LISA. We then show briefly the basic features of the instrument and we finally discuss its projected sensitivity and the extrapolation of its results to LISA. © 2005 IOP Publishing Ltd.

In a Design For Manufacturing context, Rapid Prototyping techniques are some way still considered as “new technologies”: the peculiar characteristics of the manufacturing processes are not widely known and may deeply affect the final product functionality. A Knowledge Based System, the Design Guidelines — DGLs, was developed by our Research Group at the University of Udine; it evaluated the products design, in order to verify its feasibility by DMLS (Direct Metal Laser Sintering) Rapid Prototyping technique. During the evaluation process, the DGLs also keep into consideration the aspects relating the verification step, according to the ISO-GPS principles, thus enhancing the completeness of the tool. Aim of this work was to customise the DGLs for design optimisation in FDM (Fused Deposition Modelling), also evidencing the critical aspects and proposing alternative solutions. The contents and structure of the customised version of DGLs are presented in this work.

Keywords: Fused deposition modelling , Knowledge-based systems , Rapid prototyping

Incremental forming applications are currently increasing in industry, especially for the production of small batches or single components. In fact, sufficient know-how is now available for the manufacture of simple products. However, further efforts are required to reduce the drawbacks of typical incremental forming processes, which compromise important advantages in terms of costs and flexibility. First of all the duration of the process, usually a few minutes, influences this kind of process, even if the operations are carried out on high-speed digitally controlled units. A tendency to produce inaccurate parts can reduce industrial interest with respect to incremental forming. Different approaches could be proposed to reduce this drawback, and a feasible and easily implemented strategy is the design of modified trajectories able to take into account both springback effects and stiffness reduction owing to specific clamping equipment. In this paper, such a strategy is pursued by integrating an on-line measuring system, composed of a digital inspector and a computer numerically controlled (CNC) open program. The geometry obtained is sampled in particular steps and an appropriate routine modifies the coordinates of the future punch path. This procedure of automatic control has been developed using an effective finite element (FE) code. An experimental design illustrates the potential use of the suggested methodology. © IMechE 2005.

Keywords: Incremental forming , Net shape , Sheet metal forming

Incremental Forming processes have been introduced in the recent past as an alternative to the money consuming stamping technology, when small batches have to be manufactured. Anyway, they introduce some advantages in terms of flexibility and material formability but, also, some problems such as the dimensional accuracy decreasing. In this paper, a particular application is carried out taking into account the development of an innovative technique to produce a customised ankle support. In this way Incremental Forming process has been selected for the sheet profiling, exalting the role that this technology may play when single complex product has to be manufactured. The producing procedure finishes with a measure of the dimensional accuracy that shown a good result for the desired application. © 2005 Elsevier B.V. All rights reserved.

Keywords: Ankle support , Incremental Forming , Reverse engineering

We have developed a pen device for CAD applications in virtual reality which provides novel features compared to existing systems. The SenStylus consists of a wireless pen designed to be ergonomically handled by the user for spatial interaction using a six degree of freedom optical tracking. In addition to the classic digital button(s) input, it provides analog multi-axial control, and a dual-rumble feedback output. We have integrated the device into an existing virtual reality CAD environment and extended the application functionalities with new devicespecific features. The SenStylus vibration feedback improves perception in the virtual world by controlling frequency, amplitude, and duration of the feedback, simulating a variety of responses during collisions and selection tasks. This capability enforces the visual depth sensitivity, which is critical when wo rking with complex CAD models. The multi-axial analog input provides a natural interaction paradigm to the user, thus simulating pen pressure and angle as in real world sketching and in real clay modeling. Dynamic tool-tip dimensioning and shaping are implemented as extra features. We present some applications to prove the added value of the SenStylus. The evaluation of the device received positive feedback by designers and engineers alike. The new features offered by this device can easily be extended to other VR applications using the API provided. Copyright UNION Agency - Science Press.

Keywords: 3D interaction , CAD , User interface hardware , Virtual reality