Jill Urbanic

Semi-Generative Macro-Process Planning For Reconfigurable Manufacturing

Global competition and frequent market changes are challenges facing manufacturing enterprises at present. Manufacturers are faced with new unpredicted modifications at the part design level, which require increased functionality at the system design level. Reconfigurable Manufacturing Systems (RMS) addresses this situation by providing the exact capacity needed when needed. Process planning concepts and methods should be developed to support this new manufacturing environment. Variant process planning systems with their rigid definition of the boundaries of part families do not satisfactorily support Reconfigurable Manufacturing Systems. A semigenerative macro process planning system has been developed and is reported in this paper. Precedence graphs, which depict the precedence relationships between features/operations, are reconfigured by adding and removing nodes. The problem of generating optimal macro-level process plans is combinatorial in nature and proven NP-hard. Hence, a random-based heuristic based on Simulated Annealing is tailored for this problem. Finally, a realistic case study is presented to illustrate the proposed methodology. A family of single-cylinder front covers is used. The proposed method produced good quality optimal solutions and is proven efficient in terms of computation time as demonstrated by the obtained results.

Relating additive and subtractive processes in a teleological and modular approach

Purpose – The purpose of this paper is to relate additive manufacturing (AM) and machining (CNC) synergistically in a modular approach in the design and manufacturing domains, to generate value for end‐users and manufacturers (a teleological system).Design/methodology/approach – The research methodology decomposes a part into modules, by employing a teleological systems theory approach paired with principles of modular design. Modules are manufactured with either additive manufacturing (fused deposition modeling, FDM) or machining (CNC). Process selection is determined by a decision‐making framework that quantifies strength and weakness comparisons of FDM and CNC machining processes, accomplished using the analytic hierarchy process (AHP).Findings – The developed methodology and decision‐making framework is successfully applied to the design and manufacturing of a large, complex V6 engine section sand casting pattern. This case study highlights the merits of the research.Research limitations/implications ...

Design and evaluation of reconfigurable robotic systems for 2 1/2 axis based material deposition strategies

Simulation tools need to be developed to support modeling and product/process analysis activities for material deposition processes. The long term research goal is to develop a set of virtual modeling tools to support advanced tool motions and process planning strategies for this application. The goal of this research is to develop a reconfigurable robotic platform that can adapt alternative deposition strategies while respecting the unique process-related constraints for 2 1/2 axis and 2 1/2 axis + 2 axis tool paths. A variety of topologies are investigated. For the selected systems, a parametric kinematic, dynamic and control model is developed, and results presented for kinematic and dynamic reconfigurations. An adaptability assessment is performed to determine a relative effort measure to physically reconfigure a base platform to a potential new configuration. This combined with reviewing the modeling complexity issue, is used to determine an appropriate base platform. To simulate the process realistically using existing tools, a methodology is developed to illustrate material deposition in conjunction with the tool motions for the systems investigated.

Minimizing Voids With Using an Optimal Raster Orientation and Bead Width for a Material Extrusion Based Process

Additive Manufacturing (AM) is the process of joining materials ‘layer by layer’ to make products from Computer Aided Design (CAD) model data. AM processes support faster product realization for a wide selection in industries. The Material Extrusion (ME) process is an AM process that builds a product from thin layers of extruded filaments from a semi-melted material such as a thermoplastic. In commercial systems, the software automatically generates the tool paths for both the model and any necessary supports, based on the curve geometry and the specified build parameters. The interior fill rotates 90° between each layer. Automatically generating the tool path can be the biggest weakness for this process planning strategy. Voids and discontinuities have been observed after evaluating test specimens developed to explore mechanical characteristics. Choosing an optimal raster orientation and bead width will help minimize voids and discontinuities in each layer. A mathematical model is introduced in this paper to find optimal raster orientation and bead widths based on the geometry of the slice for selected 2D extruded parts. As well, preliminary quality assessment metrics are introduced. Void analysis is performed to evaluate solution approaches, and the results compared. The future work will investigate utilizing multiple bead widths for a layer to minimize voids, and developing more comprehensive quality metrics to highlight problematic regions.Copyright

Effective Work Region Visualization for Serial 6 DOF Robots

Optimal serial 6 degree of freedom (DOF) robot path planning has challenges due to the kinematic structures, singularity conditions, and the practical reach limits due to the a path-fixture-end effector orientation and design-robot structure combination. Previous research has been done to define and visualize the functional reach limits for a robot-end effector orientation-end effector tool geometry set. This is expanded and combined with singularity region analyses to be able to visualize the total effective travel path regions for a target application (i.e., FANUC, ABB, or Comau robot families) using the MATLAB toolbox. Visualization tools that represent both the functional work region or work window and singularity regions are presented. This research will provide designers the ability to assess a wide range of industrial robot configurations comprehensively at the design or redesign stages as the valid bounded region defined in this work can be employed for subsequent downstream optimization related to velocity and acceleration control.

An Ethical Roadmap for Engineering Participatory Design and Sociotechnical Participation: A Manufacturing Case Study

Participatory design (PD) is a sociotechnical approach grounded in mutual learning between various stakeholders in a design process. The PD literature emphasizes that authentic participation requires a critical ethical foundation, which, in turn, requires designers to be aware of this ethical foundation and bring it to bear on the design process. Since this is an emerging field in engineering, and since the ethical foundation is critical, it is important for engineers to seek clarity around the ethical considerations for utilizing PD and other sociotechnical methods involving participation. The purpose of the research presented here is to contribute to this clarity, in the context of manufacturing systems design, with the following question: what are the ethical considerations involved in participatory design, in engineering research and practice? To answer this, a case study research methodology is positioned as a nexus between research and practice. A roadmap of ethical considerations relating PD and manufacturing is developed by triangulating between internationally accepted research ethics principles, a professional engineering code of ethics, and an industrial case study with eight participants engaged in PD. This ethical roadmap is useful to engineering researchers and practitioners when using PD and sociotechnical approaches where participation is involved, to encourage a high standard of ethical practice and supporting theory.Copyright

Singularity Analysis for a 6 DOF Family of Robots

Path planning for serial 6 degree of freedom (DOF) robot based systems is challenging due to their kinematic structure, the behaviour of robot based on the configuration, and singularity conditions. Understanding the singularity conditions and zones is critical for both single robot applications, and robot cells. Visual representations of singularity zones will help process designers develop valid travel paths and layout designs. MATLAB tools are employed to represent the singularity zones using fundamental kinematic equations. The target application for this research is the FANUC family of serial 6 DOF robots, and the identified singularity regions are plotted in 2D and 3D Cartesian space.

Design of a reconfigurable robot-based system for material deposition applications

Simulation tools need to be developed to support modeling and product/process analysis activities for material deposition processes. The long term research goal is to develop a set of virtual modelling tools to support advanced tool motions and process planning strategies for this application. The goal of this research is to develop a reconfigurable robotic platform that can adapt to variable product size characteristics, and alternative deposition strategies while respecting the unique process-related constraints for 2 ½ axis and 2 ½ axis + 2 axis tool paths. A variety of topologies are investigated. For the selected system, a parametric kinematic, dynamic and control model is developed for configurations of the basic platform. Results for kinematic and dynamic reconfigurations of this base platform are then presented. To simulate the process realistically using existing tools, a methodology is developed to illustrate material deposition in conjunction with the tool motions for a 3 degree of freedom (2 degree of freedom planar robot with a translational axis) configuration.

A Systematic Investigation for Reducing Shredder Residue for Complex Automotive Seat Subassemblies

Automotive shredder residue is a byproduct of the automotive recycling infrastructure and represents 15% of the overall weight of a vehicle. The byproduct is currently diverted to landfill and although the potential for recycling exists, none are currently being utilized within Canada. Consequently, the possibility of dismantling vehicle seats separately from the current vehicle dismantling process in order to remove a large portion of automotive shredder residue before the shredding process is investigated using a systems approach. Issues such as government regulations, expenses and potential revenues are discussed to determine the economical success of vehicle seat recycling.