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Disassembly takes place in remanufacturing, recycling, and disposal, with a line being the best choice for automation. The disassembly line balancing problem seeks a sequence that is feasible, minimizes the number of workstations, and ensures similar idle times, as well as other end-of-life specific concerns. Finding the optimal balance is computationally intensive due to exponential growth. Combinatorial optimization methods hold promise for providing solutions to the problem, which is proven here to be NP-hard. Stochastic (genetic algorithm) and deterministic (greedy/hill-climbing hybrid heuristic) methods are presented and compared. Numerical results are obtained using a recent electronic product case study.

Defects in fabric have been and continue to be a major source of seconds in finished garments. These defects persist despite several visual inspections and intensive efforts to remove defective parts during sewing operations. The increased use of automation in assembly steps will intensify the problem of detection and removal of fabric defects in cut‐parts. Describes a workstation utilizing machine vision which has been designed and constructed to detect and remove defective cut‐parts prior to the initiation of assembly operations. The workstation employs two vision systems — an area camera and a line camera — to inspect parts on a conveyor belt both statically and dynamically. The colour of the parts is also determined and the area and perimeter are measured to detect improperly cut parts. The acceptable parts are then stacked in a manner suitable for input to an automated sewing station. The workstation should permit placing into the assembly operations a set of defect‐free, properly‐cut and colour‐matched parts. It is estimated that this cut‐part inspection system will reduce defects in finished garments by approximately 50 per cent and should greatly simplify the labour‐intensive and costly fabric defect control systems currently in place in most apparel plants.

The purpose of this paper is to present a hybrid manufacturing system that integrates stereolithography (SL) and direct print (DP) technologies to fabricate three‐dimensional (3D) structures with embedded electronic circuits. A detailed process was developed that enables fabrication of monolithic 3D packages with electronics without removal from the hybrid SL/DP machine during the process. Successful devices are demonstrated consisting of simple 555 timer circuits designed and fabricated in 2D (single layer of routing) and 3D (multiple layers of routing and component placement).

A hybrid SL/DP system was designed and developed using a 3D Systems SL 250/50 machine and an nScrypt micro‐dispensing pump integrated within the SL machine through orthogonally‐aligned linear translation stages. A corresponding manufacturing process was also developed using this system to fabricate 2D and 3D monolithic structures with embedded electronic circuits. The process involved part design, process planning, integrated manufacturing (including multiple starts and stops of both SL and DP and multiple intermediate processes), and post‐processing. SL provided substrate/mechanical structure manufacturing while interconnections were achieved using DP of conductive inks. Simple functional demonstrations involving 2D and 3D circuit designs were accomplished.

The 3D micro‐dispensing DP system provided control over conductive trace deposition and combined with the manufacturing flexibility of the SL machine enabled the fabrication of monolithic 3D electronic structures. To fabricate a 3D electronic device within the hybrid SL/DP machine, a process was developed that required multiple starts and stops of the SL process, removal of uncured resin from the SL substrate, insertion of active and passive electronic components, and DP and laser curing of the conductive traces. Using this process, the hybrid SL/DP technology was capable of successfully fabricating, without removal from the machine during fabrication, functional 2D and 3D 555 timer circuits packaged within SL substrates.

Results indicated that fabrication of 3D embedded electronic systems is possible using the hybrid SL/DP machine. A complete manufacturing process was developed to fabricate complex, monolithic 3D structures with electronics in a single set‐up, advancing the capabilities of additive manufacturing (AM) technologies. Although the process does not require removal of the structure from the machine during fabrication, many of the current sub‐processes are manual. As a result, further research and development on automation and optimization of many of the sub‐processes are required to enhance the overall manufacturing process.

A new methodology is presented for manufacturing non‐traditional electronic systems in arbitrary form, while achieving miniaturization and enabling rugged structure. Advanced applications are demonstrated using a semi‐automated approach to SL/DP integration. Opportunities exist to fully automate the hybrid SL/DP machine and optimize the manufacturing process for enhancing the commercial appeal for fabricating complex systems.

This work broadly demonstrates what can be achieved by integrating multiple AM technologies together for fabricating unique devices and more specifically demonstrates a hybrid SL/DP machine that can produce 3D monolithic structures with embedded electronics and printed interconnects.

As rapid prototyping technologies improve in accuracy and reliability so the range of applications increases. A number of new systems have recently come on the market and already established systems are showing significant improvements in the materials being used. The systems available appear to be focused on two distinct market sectors. Machines are being used as design office support facilities or “desktop” manufacturing units. Machines are also being used as “shopfloor” systems, concentrating on downstream activities. Suggests that one future for this technology is side‐by‐side with conventional machine tools as one of the process route options for a manufacturing company. One way of achieving this may be to integrate industrial robotics with the technology in the form of flexible manufacturing (or rapid prototyping) cells.

Disturbing increase in the use of virgin resources to produce new products has threatened the environment. Many countries have reacted to this situation through regulations which aim to eliminate negative impact of products on the environment shaping the concept of environmentally conscious manufacturing and product recovery (ECMPRO). The first crucial and the most time-consuming step of product recovery is disassembly. The best productivity rate is achieved via a disassembly line in an automated disassembly process. In this chapter, we consider a sequence-dependent disassembly line balancing problem (SDDLBP) with multiple objectives that is concerned with the assignment of disassembly tasks to a set of ordered disassembly workstations while satisfying the disassembly precedence constraints and optimizing the effectiveness of several measures considering sequence-dependent time increments among disassembly tasks. Due to the high complexity of the SDDLBP, there is currently no known way to optimally solve even moderately sized instances of the problem. Therefore, an efficient methodology based on the simulated annealing (SA) is proposed to solve the SDDLBP. Case scenarios are considered and comparisons with ant colony optimization (ACO), particle swarm optimization (PSO), river formation dynamics (RFD), and tabu search (TS) approaches are provided to demonstrate the superior functionality of the proposed algorithm.

The purpose of this paper is to introduce sequence‐dependent disassembly line balancing problem (SDDLBP) to the literature and propose an efficient metaheuristic solution methodology to this NP‐complete problem.

This manuscript utilizes a well‐proven metaheuristics solution methodology, namely, ant colony optimization, to address the problem.

Since SDDLBP is NP‐complete, finding an optimal balance becomes computationally prohibitive due to exponential growth of the solution space with the increase in the number of parts. The proposed methodology is very fast, generates (near) optimal solutions, preserves precedence requirements and is easy to implement.

Since development of cost effective and profitable disassembly systems is an important issue in end‐of‐life product treatment, every step towards improving disassembly line balancing brings us closer to cost savings and compelling practicality.

This paper introduces a new problem (SDDLBP) and an efficient solution to the literature.

This paper aims to present a monitoring system and the usage of a robotic arm to remove finished parts of a three-dimensional (3D) printer build plate, enabling 3D printers to continuously build a sequence of parts.

The system relies on a 2-degree of freedom planar manipulator. The moment to remove printed parts from the printer build plate can be determined based on direct communication with the 3D printer control software or using information from a computer vision system that applies background subtraction and Speeded up Robust Features methods.

The proposed system automatically detects the end of standard 3D print jobs and controls the robotic arm to remove the part.

Lighting variation can deteriorate the response of the computer vision system, which can be minimized using a controlled illumination environment. In addition, the printer build plate edges must be free so the parts can slip off the printer build plate when the robot pushes them out.

The system enables a more practical and automatized usage of 3D printers, reducing the need of human operators.

The proposed system can reduce work hours of laboratory personnel, as there is no need to remove the printed parts manually before another job starts.

Computer vision system monitors the printing process and the automation system that enables continuous sequential 3D printing of parts. A prototype is described, which can be easily replicated with low cost parts.

This research aims to propose a methodology for a systematic, concurrent consideration of design for assembly (DFA) and disassembly guidelines and constraints for product remanufacturing. The methodology provides a holistic approach to design product from the remanufacturing perspective.

The proposed methodology incorporates parts’ integration assessment and evaluation of part complexity and accessibility taking into consideration both DFA and design-for-disassembly (DFD) guidelines and constraints. Metrics for accessibility and complexity in retrieving the remanufacturable cores from a product are evaluated to determine the best possible disassembly route considering the practical constraints which an operator might face during disassembly. As there could be more than one feasible disassembly route to retrieve a core during remanufacturing, a disassembly evaluation is conducted to determine the optimal path after combination of the parts of the assembly.

In remanufacturing, products need to be disassembled and re-assembled again. Conflicts exist between DFA and DFD. The proposed methodology serves to address these conflicting issues. The proposed methodology eases a designer’s effort systematically to incorporate both aspects, by incorporating practical consideration to determine an optimal disassembly sequence through integrating the handling aspect of assembly complexity assessment with the U-Rating disassembly effort indexing scheme to provide a quantitative evaluation of disassembly complexity, as disassembly still largely requires human effort.

Future research will explore methods to improve the user interface with features to determine feasible disassembly routes of a product automatically. This will relieve the effort of the product designer to a great extent.

This paper proposes a methodology for a systematic, concurrent consideration of DFA and DFD to provide a holistic approach to product design from the remanufacturing perspective to ease the designer’s task. Practical considerations will be made to determine the optimal disassembly route of the product. DFD will only be required to be applied to the selected disassembly route to minimize conflicts with DFA.

There is a rich body of literature on sequencing assembly and on sequencing disassembly, but little that either fuses or contrasts the two, which may be valuable for long-range planning in the closed-loop supply chain and simply convenient in terms of consistency in nomenclature and mathematical formulations. The purpose of this paper is to concisely unify and summarize assembly and disassembly formulae – as well as to add new formulations for completeness – and then demonstrate the similarities and differences between assembly and disassembly.

Along with several familiar assembly-line formulae which are adapted here for disassembly, five (two specific and three general) metrics and a comparative performance formula from disassembly-line balancing are proposed for use in assembly- and disassembly-line sequencing and balancing either directly, through generalization, or with some extension. The size of assembly and disassembly search spaces are also quantified and formulated. Three new metrics are then developed from each of the general metrics to demonstrate the process of using these general formulae as prototypes.

The three new metrics along with several of the original metrics are selectively applied to a simple, notional case study product to be sequenced on an assembly line and then on a disassembly line. Using these analytical results, the inherent differences between assembly and disassembly, even for a seemingly trivial product, are illustrated.

The research adds several new assembly/disassembly metrics, a case study, unifies the evaluation formulae that assembly and disassembly hold in common as well as structuring prototype formulae for flexibility in generating new evaluation criteria for both, and quantifies (using the case study) how assembly and disassembly – while certainly possessing similarities – also demonstrate measurable differences that can be expected to affect product design, planning, production, and end-of-life processing.

The purpose of this paper is to efficiently solve disassembly line balancing problem (DLBP) and the sequence-dependent disassembly line balancing problem (SDDLBP) which are both known to be NP-complete.

This manuscript utilizes a well-proven metaheuristics solution methodology, namely, variable neighborhood search (VNS), to address the problem.

DLBPs are analyzed using the numerical instances from the literature to show the efficiency of the proposed approach. The proposed algorithm showed superior performance compared to other techniques provided in the literature in terms of robustness to reach better solutions.

Since disassembly is the most critical step in end-of-life product treatment, every step toward improving disassembly line balancing brings us closer to cost savings and compelling practicality.

This paper is the first adaptation of VNS algorithm for solving DLBP and SDDLBP.