Next Generation Factory Layouts Saifallah Benjaafar, University of Minnesota Shahrukh Irani, Ohio State University Sunderesh Heragu, Rensselaer Polytechnic Institute

> Flexible > Modular > Reconfigurable > Agile Characteristics

> High product variety > Product demand volatility > Low production volumes > Short product lifecycles Needs

Functional versus Cellular Layouts Functional layout Cellular layout

> Material handling inefficiency > Scheduling complexity > Vulnerability to changes in product mix/routings/volumes > Prohibitive re-layout costs Limitations of functional layouts

> Rapid obsolescence > Workload unbalances > Limited flexibility > Resource duplication Limitations of cellular layouts

Distributed Layouts Functional layout Partially distributed layout Fully distributed layout

> Effective hedging against future fluctuation in product mix, volume and routings > Efficient material handling > Flexible workload allocation > Rapid formation of virtual cells Advantages

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

> 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. Modular Layouts

> 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. Motivation

Layout Modules (a) Flowline Module (c) Cell Module C D E B A AB C GH D EF (b) Branched Flowline Module (d) Machining Center Module A B C D E (f) Patterned Flow Module A+B+C ( e) Functional Layout Module A BCD E ABCDE

Example Modular Layout Flowline for PHOTO Functional Layout for ETCH Functional Layout for FILM Department Flowline for BACKEND Cell for ETCH, IMPLANT and PHOTO Flowlines for DIFF Functional Layout for ETCH, FILM and PHOTO Flowline for ETCH

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

> 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. Reconfigurable Layouts

> 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. Motivation

As a result, a layout could be changed several time a year!

Re-Layout Design Procedure Design Data + New Product Design + New Processes Selected Production Data + Expected Volume + Changed Product Mix Revised Material Flow Matrices / Adjacency Matrices Current Facility LayoutRelocation Costs Material Handling Costs Facility Layout Design Output + Machine Locations + Material Flow Plan

> Layouts are designed with agility-based criteria, such as cycle time, work-in-process, and production throughput. Agile Layouts

A Queueing-Based Layout Design Procedure Material handling system Processing departments

Input bufferOutput buffer Empty trip from destination of previous delivery to origin of current request Full trip from the origin of current request to its destination department

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. Queueing Effects

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. Summary