Search

Purpose: This study aims to develop an optimal tolerance allocation strategy involves integrating the unique transfer (UT) approach and the difficulty coefficient evaluation (DCE) routine in an interactive hybrid method. This method combines the strengths of both UT and DCE, ensuring simultaneous utilization for enhanced performance. The proposed tolerancing model manifests an integrated computer-aided design (CAD) tool. Design/methodology/approach: By combining UT and DCE based on failure mode, effects and criticality analysis (FMECA) tool and the Ishikawa diagram, the proposed collaborative hybrid tool ensures an efficient and optimal tolerance allocation approach. The integration of these methodologies not only addresses specific transfer challenges through UT but also conducts a thorough evaluation of difficulty coefficients via DCE routine using reliability analysis tools as FMECA tool and the Ishikawa diagram. This comprehensive framework contributes to a robust and informed decision-making process in tolerance allocation, ultimately optimizing the design and manufacturing processes. Findings: The presented methodology is implemented with the aim of generating allocated tolerances that align with specific difficulty requirements, facilitating the creation of a mechanical assembly characterized by high quality and low cost. To substantiate and validate the conceptual framework and methods, an integrated tool has been developed, featuring a graphical user interface (GUI) designed in MATLAB. This interface serves as a platform to showcase various interactive and integrated tolerance allocation approaches that adhere to both functional and manufacturing prerequisites. The proposed integrated tool, designed with a GUI in MATLAB, offers the capability to execute various examples that effectively demonstrate the benefits of the developed tolerance transfer and allocation methodology. Originality/value: The originality of the proposed approach is the twining between the UT and DCE simultaneous in an integrated and concurrent tolerance transfer and allocation model. Therefore, the proposed approach is named an integrated CAD/tolerance model based on the manufacturing difficulty tool. The obtained results underscore the tangible advantages stemming from the integration of this innovative tolerance transfer and allocation approach. These benefits include a notable reduction in total cost and a concurrent enhancement in product quality.

Design centers and industrial organizations emphasize that process planning is one of the most important pillars that guarantee an efficient production system, as it represents the principal link between design and manufacturing in target of avoiding time and cost wastes. In order to ensure an effective assembly/disassembly process implementation, several parameters have to be properly treated during the planning phase: product data collection and analysis, alignment with customer demand forecast, capacity calculation and equipment/tools planning, in addition to identify layout steps and process setting-up phases. One of the most important procedures that initiate a product remanufacturability and recyclability is disassembly process. That’s why it is mandatory to predict the disassembly process planning and predefine it in advance. This research paper proposes an analytical formulation of disassembly process planning prediction: it is a proactive procedure which model need of equipment, layout and line balancing from the early design phase of product. The disassembly process elements are defined with reference to a previously extracted disassembly plans (DP) from literature, and the disassembly process planning prediction is applied on an optimal disassembly plan selected based on two combined indicators which are Quality index (Qi) and timing index (Ti).

Every industrial organization, whether it deals with an assembly or a disassembly process, is definitely putting a huge focus on how to optimize its operative mode by reducing: process variation, frequent changes of production tools, quality issues, wastes. That’s why, disassembly plan generation (DP) is a very supportive tool that detects and identifies difficulties and probable blocking assembly/disassembly situations from the early design steps and avoid them. This anticipation is quite beneficial to manufactories point of view cost, time and quality of products as it returns with a remarkable reduction in production stopping time and products’ defects, as a result reduction in cost of production. In order to ameliorate DP algorithm decision generation and make it very similar to real manufacturing circumstances, this article comes with a new approach that combines between two main metrics, which are the Quality index (Qi) and the Timing index (Ti), as criteria while selecting optimal and feasible DP. Qi is calculated based on the failure mode, effects and criticality analysis method (FMECA), on the other side, Ti represents the real processing time index with reference to real manufacturing constraints (workplace, lay-out, work-flow, tools, machines…). To highlight the effectiveness of the proposed approach, an industrial gear box example is simulated and compared to a literature study.

Currently and in view of technological development, mechatronic systems have become more and more complex. This will undoubtedly influenc the design of products. For this reason, designers do not stop developing new solutions to best ensure customer satisfaction on functional dimensional and geometrical requirements. However, to achieve a finished product satisfying all stakeholders, designers should face a multitud of problems. Among them, the difficulty of data exchange between the different developers contributing to the design process of a finishe product. Several research works have focused on data exchange between Computer Aided Design (CAD) and Computer Aided Engineering applications (CAE) or at the CAD development and manufacturing levels. However, few works study the interoperability between all the produc development levels and the system engineering one. For instance, the lack of continuity between the system-engineering model which has global view on the product, and the CAD model which integrates the parts and assembly CAD data, causes an enormous lost time in th verification and validation process of requirements. In this paper a methodology allowing the interoperability between the system leve specifications and the CAD model of a product being designed is proposed. Based on SysML diagrams, the customer needs and the functiona analysis of the product lead to the definition of the initial structure of the product assembly. The results of this step are used as an input by th CAD designer to detail the architecture of the mechanical assembly. Finally, the product assembly data required for verification and validatio are extracted from the CAD model and then used back to enrich the preliminary SysML model. The system engineer uses the collected data i the SysML model to check and validate the product requirements according to a V model. A pedal of a bicycle was used as an example to illustrat and prove the effectiveness and efficiency of the proposed approach.

Assembly Sequence Planning (ASP) is one of the well-known optimization problems in the manufacturing industry. It represents a great deal of interest over the past three decades. This paper aims to present a method for generating ASP, taking into account the stability assignment during assembly’s operations. The developed method uses the topological and geometrical assembly constraints extracted and generated from CAD system (assembly constraints, mass and center of gravity of components, interference and contact matrices), to guarantee the generation of a feasible ASP. The main contribution of this research is the development of a method which respects the stability assignment of heavy machines during the assembly’s operations. Also, it reduces the design costs and minimizes the time of replacement or repair of failing components of industrial equipments, which has become complicated task given the complexity of today’s mechanisms. A validation example is used to highlight the advantages of the proposed approach.

The cost and quality of the product depend directly on the tolerance values. Especially, the tolerance allocation is an important engineering function involving a direct impact on compliance with functional and manufacturing requirements. The mastery of this function requires the use of a tool to analysis the reliability of the process as well as a method to optimize the tolerances. Thus, this work proposes an innovative tolerance allocation method based on the Failure Mode, Effects and Criticality Analysis (FMECA) tool as well as a Lagrange Multiplier (LM) approach.

Disassembly sequencing is a concurrent research subject in design for life-cycle. Many past and recent researches are made to give practical methods for disassembly sequencing. The problem of assembly information’s modeling is one of the important sub-problems of disassembly simulation. The problem includes connection determination, disassembly direction identification, and part mobility state definition. In the present paper, the authors propose a new representation model of disassembly directions, starting from geometric and assembly data of computer aid design models. This model is based on a mobility matrix definition for every part. This matrix is also called disassembly direction matrix. The model gives information about the mobility state of a part during disassembly sequencing by updating its mobility matrix. Mobility state data are used in a practical computing of disassembly sequence feasibility. In this paper, theoretical explication of this modeling is given and validated by computational results. In the validation section, the model is applied to a computer aid design mechanism using a selective disassembly.

To develop a simulation tool for automatic disassembly in computer aid design (CAD) environment two difficulties are found: the huge space of generated sequences and their feasibility especially in combinatory generation. This article deals with automatic sequence generation for selective disassembly of mechanical product. Starting from a CAD model a new appropriate connection tree of a target component is constructed. This tree aims at reducing space solution by eliminatory rules. The generation of sequence is based on reading of connection tree branches and eliminatory tests of feasibility. The feasibility is checked by updating the disassembly mobility of each sequence’s element. A case study is presented to prove the effectiveness of the proposed approach.

Assembly sequence planning has drawn the attention of many researchers over the last years. Despite, the great development of CAD software in many aspects (simulation algorithms, interfaces, and ergonomics), automatic generation of assembly sequence planning from CAD assembly remains an issue to improve especially with the increasing complexity of industrial products. In this paper, an approach of assembly sequence planning generation from a CAD assembly model is presented. In order to generate feasible assembly sequence planning, the developed approach begins with the exploration of CAD assembly. Then, a collision analysis is performed to identify all possible obstacles during the components’ motion. An example of CAD assembly is presented in all sections of this paper in order to demonstrate the efficiency of the proposed approach.

Disassembly sequence planning is a relatively new subject and has only recently gained interest in the research literature. Disassembly simulations are important not only for improving product design, but also for maintaining an updated process plan, which becomes a tedious and complicated task given the complexity of today’s mechanisms. The crucial issue, in the generation of disassembly plans, is the rise in the amount of sequences, especially with the increase of the number of parts in the mechanism. For this reason, it is crucial to seek an optimal feasible method for the disassembly process. In this paper, an optimized disassembly process based on a genetic algorithm is proposed. The method takes into account several criteria such as maintainability of usury component, part volume, tools change and the change of disassembly directions. The results obtained demonstrate the satisfactory side of these criteria to identify a feasible disassembly sequence.

Nowadays, numeric simulation becomes one of the most important activities of the product development cycle. To accelerate the design and simulation tasks, it is necessary to adapt the CAD model before the simulation process. This paper presents a method based on an original algorithm in order to adapt and simplify the design geometric model to a simulation by finite elements method. It consists in the idealization of the CAD geometry by eliminating details (holes, chamfers, etc.). These details increase the computing time due to a refined mesh in these details, which are considered as stress hubs, without providing more precision in the simulation. An implementation of the proposed algorithm using the Open Cascade platform is also presented. The last part of this paper presents two examples of mechanical parts, which are simulated before and after idealization. The results of simulation illustrate the major contribution of the proposed method in terms of computing time gain, without so much changing the exactitude of results.

Nowadays, not only the production but also the design of industrial products is subject to severe constraints in terms of time, quality and delay. In order to satisfy these constraints, it is necessary to efficiently integrate the most recurrent tasks of the design process. For a large majority of mechanical products, the integration of mechanical analysis into the design process is one of the most obvious and crucial requirements, particularly during the early stages of design. This article presents an original model of design and analysis process interoperability, based on the concept of mechanical analysis features and a semantically rich product model. It is intended to support a variety of typical analysis tasks that are frequently required during the mechanical design process. The authors firstly present a brief survey of CAD/analysis integration approaches in order to position their contribution within this domain. Then, a general structure of analysis features is justified by means of experimental results. In order to highlight the modes of interoperability between design and analysis, the authors detail the main characteristics of the product model upon which the design activity is based. This delineation is followed by a formal description of the analysis features, and a proposition for their organisation in feature catalogues. The authors then consider the implementation aspect for these models, and present a scenario illustrating the benefits and current limitations of their approach. The evaluation of the approach is discussed in the conclusion.