Robert IACOB, Diana POPESCU
University Politehnica of Bucharest
313, Splaiul Independentei, 060032 Bucharest 6, Romania
robert.iacob@gmail.com, diana@mix.mmi.pub.ro

Abstract: The paper presents the development of a new software tool integrated with SolidWorks CAD system for generating feasible disassembly directions based on the concept of mobility operator. In generating the disassembly path of a component, our approach considers that two steps should be undertaken: first, the interface between components is broken and then the component is extracted from the assembly by translating it along a collision free removal path. Different data from the CAD model of the assembly is automatically detected, such as: geometrical constraints, contact surfaces relative position, common area, components neighbours, etc. Based on this information, a general mobility operator is deployed, which is further used to evaluate the families of trajectories associated to the contacts between different components of a mechanical system. Thus, the developed mobility operator mathematically expresses all possible movements between assembly components (rotations, translations and helical movements), and it can be used for a real time graphical representation of components mobilities, mandatory aspects in developing a virtual environment for simulating the Assembly/Disassembly (A/D) tasks as part of an efficient Product Design Process (PDP).

Keywords: assembly/disassembly, disassembly planning, geometrical constraint, mobility operator

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CITE THIS PAPER AS:
Robert IACOB, Diana POPESCU, Generation of Disassembly Directions Based on Component Mobility, Studies in Informatics and Control, ISSN 1220-1766, vol. 22 (4), pp. 307-318, 2013. https://doi.org/10.24846/v22i4y201306

1. Introduction

Although the paradigm of Environmental Conscious Manufacturing (ECM) is not new [Gungor, 1999], [Mascle, 2008], the last couple of years showed an increasing interest and concern in designing and manufacturing products whose components can be recycled or reused in a high percentage. This is due to the reinforcement of European directives such as WEEE 2002/96/EC on Waste Electrical and Electronic Equipment or 2000/53/EC on end-of-life vehicles, which extends producers responsibility on the entire life cycle of a product, therefore also over the components/materials re-using or recycling activities. Products should be designed to be disassembled at the end of their life cycle and parts of them to be used in generating other products, by refurbishing, reuse, recycling or to be safely disposed, in case of dangerous materials/components.

Therefore, in this competitive world and in the global context of concern over the environment and resources, the producers need to reconsider the design process of a product as part of a larger perspective which includes a correct assessment of the impact of different design decisions on the post-consumer stage. In this sense, every bad design decision can cause a reduction on the producer market share and even to its economic failure. Solutions should be found for satisfying client requirements, ensuring profitability for producer and complying with regulations and laws, all in the same time. Thus, there is a need of tools – here including software applications – which can help engineers to take well documented design decisions when modeling a product, leading to a decrease of the costs and time associated to assembly, repair, disassembly or recycling operations.

In this context, the current research proposes an intelligent software tool for assisting the disassembly planning. This tool is integrated with SolidWorks CAD system for generating feasible dismounting plans and it is based on a mobility operator formed by two elements: the mathematical description of the general movements of a component and the real time graphical representation of the component mobility relative to its neighbours.

The proposed software application can assist engineers in establishing valid disassembly plans based on the 3D CAD representation of the product. Having, from the design phase of a product, the complete information of the disassembly operations and components valid movements can be useful in the early determination of the architecture of a mechanism, machine, robot or disassembly tool adapted to perform the operations in question, and also for estimating disassembly costs and time.

From this point forward, the paper is organized as follows. Chapter 2 presents a literature study grouped in two major categories: researches focused on using unit sphere for mapping valid disassembly directions and software applications for disassembly sequence planning. Our approach extends the existing concepts in order to include all the possible movements. Moreover, as another novelty, the software application integrates the mobility operator with the 3D CAD representation of the product for generating feasible disassembly directions.