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Next Generation Factory Layouts. Saifallah Benjaafar, University of Minnesota Shahrukh Irani, Ohio State University Sunderesh Heragu, Rensselaer Polytechnic Institute. Characteristics. Flexible Modular Reconfigurable Agile. Needs. High product variety Product demand volatility
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Next Generation Factory Layouts Saifallah Benjaafar, University of Minnesota Shahrukh Irani, Ohio State University Sunderesh Heragu, Rensselaer Polytechnic Institute
Characteristics Flexible Modular Reconfigurable Agile
Needs High product variety Product demand volatility Low production volumes Short product lifecycles
Functional versus Cellular Layouts Functional layout Cellular layout
Limitations of functional layouts Material handling inefficiency Scheduling complexity Vulnerability to changes in product mix/routings/volumes Prohibitive re-layout costs
Limitations of cellular layouts Rapid obsolescence Workload unbalances Limited flexibility Resource duplication
Distributed Layouts Functional layout Partially distributed layout Fully distributed layout
Advantages Effective hedging against future fluctuation in product mix, volume and routings Efficient material handling Flexible workload allocation Rapid formation of virtual cells
Design Procedure for Distributed Layouts Department dis-aggregation procedure Distribution of demand scenarios Product process routings Product unit transfer loads Travel distances Flow allocation procedure Layout design procedure
Modular Layouts Layouts are constructed as a network of basic modules. Each module is a group of machines in a portion of the overall facility that has a flow pattern characteristic of a traditional layout.
Motivation No single prevailing layout configurations can individually describe the complex material flow network in a multi-product manufacturing facility. Modules can be added and removed as needed. It captures the efficiency of each layout configurations without the associated limitations.
Layout Modules C D A B G H A B C D E E F A+B+C B D B C D A C E A E (a) Flowline Module (b) Branched Flowline Module C B D A E (d) Machining Center Module (c) Cell Module (e) Functional Layout Module (f) Patterned Flow Module
Example Modular Layout Functional Layout for ETCH Flowline for ETCH 2.06 2.08 2.09 2.10 2.07 Flowline forPHOTO 2.01 Functional Layout for 7.03 7.02 7.01 3.08 FILM Department 5.01 5.02 5.03 5.04 5.05 5.06 5.07 7.04 7.05 3.04 3.07 2.05 6.01 3.01 3.02 5.02 3.04 3.05 5.03 Flowline for BACKEND 3.06 5.04 5.05 2.02 4.01 1.03 1.04 1.05 Cell for ETCH, IMPLANT and PHOTO 1.02 1.01 Functional Layout for ETCH, FILM and PHOTO Flowlines for DIFF
String Matching-Based Design Procedure Extract common sub-strings Identify predominant product routings Aggregate common sub-strings and form preliminary modules Module selection and layout design
Reconfigurable Layouts Layouts are physically reconfigured (by moving resources and reconfiguring the material handling system) on short notice due to change in product mix or production volumes.
Motivation In many industries, fabrication and assembly workstations are light and can be easily relocated. Newer processing technologies permit light weight equipment. Light weight equipment could be mounted on wheels and easily moved along suitably designed tracks embedded in the shop-floor.
Re-Layout Design Procedure Design Data Production Data + New Product Design + Changed Product Mix + New Processes Selected + Expected Volume Revised Material Flow Matrices / Adjacency Matrices Current Facility Layout Relocation Costs Material Handling Costs Facility Layout Design Output + Machine Locations + Material Flow Plan
Agile Layouts Layouts are designed with agility-based criteria, such as cycle time, work-in-process, and production throughput.
A Queueing-Based Layout Design Procedure Material handling system Processing departments
2 Full trip from the origin of current request to its destination department 1 3 Empty trip from destination of previous delivery to origin of current request 4 Input buffer Output buffer
Queueing Effects Congestion is affected by: travel distances (empty and full travel) travel distance variability number and capacity of material handling devices dispatching policies processing time distributions utilization of processing departments
Queueing Effects Reducing full travel does not always improve performance. Full travel- optimal layouts can be congestion-infeasible. Congestion is affected by both the mean and variance of travel times. Congestion is affected by non-material handling factors.
Summary Although most factories of the future will need customized layout solutions, the produced layouts must be robust, adaptable, and agile. This project is exploring novel ways of achieving this goal.