| 1. |
- Bi, Z. M., et al.
(författare)
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Reconfigurable Manufacturing Systems: The State of the Art
- 2008
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Ingår i: International Journal of Production Research. - : Taylor & Francis. - 0020-7543 .- 1366-588X. ; 46:4, s. 967-992
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, general requirements of next generation manufacturing systems are discussed, and the strategies to meet these requirements are considered. The production paradigms which apply these strategies are also classified. Particular emphasis is put on the paradigm of Reconfigurable Manufacturing System (RMS). Some key issues of the RMS design are discussed, and a critical review is presented concerning the developments of RMSs. Finally, suggestions of the RMS research are made and future research directions are identified.
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| 2. |
- Brander, Pär, et al.
(författare)
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Cyclic lot scheduling with sequence-dependent set-ups : a heuristic for disassembly processes
- 2005
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 43:2, s. 295-310
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Tidskriftsartikel (refereegranskat)abstract
- The importance of material and product recovery is steadily increasing, mainly due to customer expectations and take-back obligations. Disassembly is a major operation in material and product recovery, since returned products are often disassembled to separate materials and components. The paper considers the problem of scheduling several items on a single disassembly facility. It develops a cyclic lot-scheduling heuristic for disassembly processes with sequence- dependent set-ups, resulting in disassembly frequencies for the items. Additionally, the way the problem is formulated allows calculation of the profitable use of the facility. The disassembly frequencies and the profitable use of the facility are used to create a cyclic schedule.
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| 3. |
- Brander, Pär, et al.
(författare)
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Economic lot scheduling problems incorporating a cost of using the production facility
- 2009
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 47:13, s. 3611-3624
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers scheduling the production of several different items on a single machine with constrained capacity, commonly known as the Economic Lot Scheduling Problem (ELSP). Most traditional approaches for the ELSP consider the sum of the setup cost and inventory holding cost and provide cyclic schedules that minimize this sum. In practice, there are not only costs for setups and inventory holding, but also costs for operating the production facility due to e.g. electricity, service, maintenance, tools, operators etc, which depend on the number of hours the facility is operating per working day. In this paper, we modify the traditional cost function to include not only setup and inventory holding cost but also a time variable cost for operating the production facility. The paper shows it is possible to adapt a previous heuristic procedure to this complemented cost. The model can help to determine cyclic schedules and the number of production hours per working day.
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| 4. |
- Cai, Ningxu, et al.
(författare)
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Adaptive setup planning of prismatic parts for machine tools with varying configurations
- 2008
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Ingår i: International Journal of Production Research. - : Taylor & Francis. - 0020-7543 .- 1366-588X. ; 46:3, s. 571-594
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Tidskriftsartikel (refereegranskat)abstract
- Setup planning for machining a part is to determine the number and sequence of setups (including machining features grouping in setups) and the part orientation of each setup. Tool accessibility plays a key role in this process. An adaptive setup planning approach for various multi-axis machine tools is proposed in this paper focusing on kinematic analysis of tool accessibility and optimal setup plan selection. In our approach, feasible Tool Access Directions (TADs) of machining features are denoted by partially sequenced unit vectors; The Tool Orientation Spaces (TOS) of different multi-axis machine tools are generated according to their configurations through a kinematic model, and represented on a unit spherical surface. Starting from a 3-axis-based machining feature grouping, all possible setup plans of a given part for different types of machine tools (3-axis, 3-axis with an indexing table, 4-axis, and 5-axis machines) can be achieved effectively by tool accessibility examination. The optimal setup plans are selected from obtained candidates by evaluating both their locating and grouping factors. A so-generated setup plan can provide not only the best coverage of machining features and the primary locating directions but the optimal orientations of the work-piece for each setup. Only prismatic parts are considered in this proof-of-concept study, and the algorithms introduced in this paper are implemented in MATLAB. A case study is conducted to validate the algorithms.Setup planning for machining a part is to determine the number and sequence of setups (including machining features grouping in setups) and the part orientation of each setup. Tool accessibility plays a key role in this process. An adaptive setup planning approach for various multi-axis machine tools is proposed in this paper focusing on kinematic analysis of tool accessibility and optimal setup plan selection. In our approach, feasible Tool Access Directions (TADs) of machining features are denoted by partially sequenced unit vectors; The Tool Orientation Spaces (TOS) of different multi-axis machine tools are generated according to their configurations through a kinematic model, and represented on a unit spherical surface. Starting from a 3-axis-based machining feature grouping, all possible setup plans of a given part for different types of machine tools (3-axis, 3-axis with an indexing table, 4-axis, and 5-axis machines) can be achieved effectively by tool accessibility examination. The optimal setup plans are selected from obtained candidates by evaluating both their locating and grouping factors. A so-generated setup plan can provide not only the best coverage of machining features and the primary locating directions but the optimal orientations of the work-piece for each setup. Only prismatic parts are considered in this proof-of-concept study, and the algorithms introduced in this paper are implemented in MATLAB. A case study is conducted to validate the algorithms.
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| 5. |
- Cai, Ningxu, et al.
(författare)
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GA based Adaptive Setup Planning toward Process Planning and Scheduling Integration
- 2009
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Ingår i: International Journal of Production Research. - : Taylor & Francis Group. - 0020-7543 .- 1366-588X. ; 47:10, s. 2745-2766
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Tidskriftsartikel (refereegranskat)abstract
- Setup planning of a part for more than one available machine is a typical combinatorial optimisation problem under certain constraints. It has significant impact not only on the whole process planning but also on scheduling, as well as on the integration of process planning and scheduling. Targeting the potential adaptability of process plans associated with setups, a cross-machine setup planning approach using genetic algorithms (GA) for machines with different configurations is presented in this paper. First, based on tool accessibility analysis of different machine configurations, partially sequenced machining features can be grouped into certain setups; then by responding to the requirements from a scheduling system, optimal or near-optimal setup plans are selected for certain criteria, such as cost, makespan and/or machine utilisation. GA is adopted for the combinatorial optimisation, which includes gene pool generation based on tool accessibility examination, setup plan encoding and fitness evaluation, and optimal setup plan selection through GA operations. The proposed approach is implemented in a GA toolbox, and tested using a sample part. The results demonstrate that the proposed approach is applicable to machines with varying configurations, and adaptive to different setup requirements from a scheduling system due to machine availability changes. It is expected that this approach can contribute to process planning and scheduling integration when a process plan is combined with setups for alternative machines during adaptive setupplanning.
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| 6. |
- Grubbström, Robert W., et al.
(författare)
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Analysis of standard ordering policies within the framework of MRP theory
- 2006
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 44:18-19, s. 3759-3773
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Tidskriftsartikel (refereegranskat)abstract
- A number of different standard ordering policies are presented within the methodology of Material Requirements Planning (MRP), such as Lot-For-Lot (L4L), Fixed Order Quantity (FOQ), Fixed Period Requirements (FPR), etc. In MRP theory the time development of the production-inventory system is determined by a set of fundamental equations for available inventory, total inventory and backlogs using Input-Output Analysis for capturing the Bill of Materials and Laplace transforms for describing the advanced timing requirements. This paper aims at formally introducing standard ordering policies into the fundamental equations of MRP Theory in order to analyse the possibility to obtain closed-form expressions for the time development of the system, when such rules are applied.
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| 7. |
- Grubbström, Robert W., et al.
(författare)
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Optimal production opportunities in a remanufacturing system
- 2006
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 44:18-19, s. 3953-3966
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, remanufacturing has emerged in various industrial sectors, and it adds an additional production alternative apart from the conventional manufacturing process. With remanufacturing, a used return product is often disassembled, reprocessed, and then reassembled into a new product. The remanufactured product is often of the same quality as those from regular manufacturing. Even though remanufacturing saves a substantial cost of materials, it often requires more labour and other inputs. Thus, it becomes important to examine the expanded production opportunity of the system. In this paper, we therefore make a first attempt to model such a system with respect to its optimal production. This model is based on the Cobb-Douglas (Wicksell) production function. More specifically, we focus on how labour costs, material costs, and the budget influence optimal production decisions. Explicit properties of the optimal plan are derived and presented as theorems. Results of this study are intended to provide a guideline for managers to make sound decisions, when dealing with the increasingly important remanufacturing systems.
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| 8. |
- Hallgren, Mattias, et al.
(författare)
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Differentiating manufacturing focus
- 2006
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 44:18-19, s. 3863-3878
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Tidskriftsartikel (refereegranskat)abstract
- In order for a manufacturing firm to be competitive, by supporting the market requirements through the manufacturing function, manufacturing should focus on a narrow set of tasks. Focused manufacturing is concerned with the perspectives when designing a manufacturing facility, be it a factory, plant, or plant within a plant. Traditionally, focus has been on the product, the process, or the manufacturing task based on competitive priorities (order winners and qualifiers). So far, the literature implies that a certain facility should have only one focus. In this paper, we present a framework that differentiates focus with respect to different parts of the manufacturing value chain. The point around which focus needs to be differentiated is the customer order decoupling point. We associate alternative types of focus relative to the customer order decoupling point, separating the upstream and downstream parts, and create a framework for choosing focus and how to differentiate manufacturing focus.
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| 9. |
- Johansson, Eva, et al.
(författare)
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Evaluation of materials supply systems during product development projects
- 2006
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 44:5, s. 903-917
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to analyse how materials supply systems can be evaluated during product development projects in a concurrent engineering context. The focus is on performance assessment of materials supply systems and the input data required. A case study was conducted in close cooperation with a company and two performance measures were assessed during the concept definition phase and recalculated during the product and process validation phase. The results show that preliminary input data can be used to calculate performance measures by means of the following approaches: indicators, standards or scenarios. Furthermore, it is discussed how performance assessment can assist the materials supply systems design process in a concurrent engineering context by facilitating early problem discovery, early decision-making, and common understanding.
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| 10. |
- Johansson, Eva, 1969-
(författare)
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Information management for materials supply systems design
- 2009
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Ingår i: International Journal of Production Research. - Oxon : Taylor & Francis. - 0020-7543 .- 1366-588X. ; 47:8, s. 2217-2229
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to categorise difficulties related to release and use of information for materials supply systems design during product development projects as well as specific approaches to deal with them. In the literature it has been argued that materials supply systems design should form one dimension of concurrent engineering and be coordinated with product and production systems design although little research on how to manage it has been presented. The research presented in this paper is based on multiple sources of data, mainly gathered by means of three case studies conducted at two companies from the automotive industry. The difficulties are categorised in terms of whether or not they are related to a concurrent engineering context. The approaches are categorised with regard to whether or not they focus on difficulties related to a concurrent engineering context, and whether or not they focus on the materials supply systems designers and their work.
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