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Systems for Managing Mobile Production Resources

by Jeffrey D. Lindsay, Fung-jou Chen, Walter Reade and Ron Edens

The following article was published Dec. 20, 2002 on as Article 10606D.

Table of Contents

Systems for Managing Mobile Production Resources

Jeffrey D. Lindsay, Fung-jou Chen, Walter Reade and Ron Edens
Dec. 13, 2002


In the past, establishing a mill or other production facility required the selection of a site which would be suitable for many years or decades. Plans to construct new mills were often abandoned in light of uncertainty about future political or regulatory situations, uncertainty about the dependability of raw materials, and many other factors. However, advances in modular mill construction and the development of mobile mills (sometimes called "mini-mills" ) is now beginning to make it possible for many products, once manufactured only by large production facilities permanently tied to single locations, to now be manufactured with smaller, relocatable production facilities. Mobile mills may be self-contained facilities mounted on platforms that can be moved by truck (e.g., 40-foot long platforms), by train, barge, or other means.

In some cases, essentially all the piping and wiring of a mobile mill is completely contained on the mobile platform. Users must simply provide a power supply and raw materials for operation. In some variations, the mobile mills are not located on land but on floating platforms such as barges or ships, and may have self-contained power sources. Groups of mobile mills, whether on land or water, can be joined or can work cooperatively to achieve production that normally would take a much larger facility than could be mobilized as a single unit.

Mobile mills can benefit from recent advances in modular technology for manufacturing. Modular components within permanent production facilities have become increasingly common and are a tool for improving the flexibility of the production facility. For example, the drying of paper and textile webs can be done with a variety of movable dryer modules, such as those disclosed by Stephansen in US Patent No. 4,514,913, "Apparatus for Drying a Moving Web Having Movable Dryer Modules," issued May 7, 1985. Entire mills have been built with modular construction. See, for example, D. Waters, "Modular Construction Keeps Mill Expansion at Remote Site On Target," Pulp and Paper, Vol. 60, no. 3, pp. 173-176 (March 1986). Modular components for production of absorbent articles is also already known.

As a related example, technology also exists for the construction of a modular tissue machine that does not need to be integrated with the foundations of a mill. For example, installation of a new modular crescent former tissue machine is under way at Charles Turner's Springside mill in Bolton, UK, which will produce 15,000 ton/y with a trim width of 2.75 m. Modular tissue machines freed from the need to be integrated with mill foundations open the possibility not only for prefabricated construction, but relocatable tissue machines or tissue components to permit production of tissue to be optimized with respect to changes in the geographical distribution of demand or resources, as well as changes in regulations and other factors that can make a given location more or less attractive for tissue production.

Many industries have failed to take advantage of the numerous opportunities provided by mobile mills. However, increasing global uncertainty about the long-term suitability of any single location and the improving economics for more flexible production facilities may soon enable relocatable production facilities to be economically favored for a large number of products, at least in some parts of the world. While less developed countries have been proposed as ideal candidates for mobile production facilities, more developed countries also face difficulties that may serve as incentives for further mobilization.

Although the use of one or more mobile mills may have many potential advantages for corporations and governments, the value of these mills is unlikely to be fully realized without the use of a sophisticated management system. Such a system would be required to manage the many different considerations for determining the optimum deployment location of one or more mobile mills. This would include proper codification of relevant data, the ability to perform complex optimization procedures, and the ability to provide analysis and/or decision support.

We propose a system for managing multiple relocatable production facilities to optimize production or profitability by moving the production facilities in light of changing conditions, including geopolitical conditions, regulatory environment, raw materials supplies, climate changes, and so forth. The system can be applied in the production of any suitable product or raw material, including tissue and paper, absorbent articles, cosmetics, health and beauty aids, other personal care articles, baked goods and other edible products, electronics, textiles, articles of clothing, printed materials, disposable and durable goods, vehicles, household articles, children's toys, roofing materials, packaging materials, ceramics, wood products, machined metal goods, plastics, pharmaceuticals, paints and varnishes, inks, rubber goods, medical devices (syringes, catheters, gloves, gowns, sponges, hemostatic clamps, etc.), nonwoven materials, and so forth. Mobile waste treatment facilities (e.g., incinerators) can also be considered. Some manufacturing operations, such as papermaking, may require a larger series of unit operations than can be mounted onto a single mobile platform, but multiple mobile units may then be combined to create a partitioned mobile mill.

The proposed management system for mobile mills is computer-assisted, allowing numerous variables to be considered in optimizing production plans, resource allocation, product mix, and mill locations to better comply with the demands of market conditions, raw materials availability, local regulatory environment, and other social, legal, economic, and market issues.

Rather than managing each mill as a separate resource, a corporation with multiple relocatable mills can manage the entire system in an integrated manner to optimize the use of resources and the distribution of products made. The integrated approach can be used to optimize the location of the mills and products made there to best meet the demands of the market and increase overall profitability of the corporation. This can be accomplished with the help of an administrative program, which can be a software module integrated with an ERP (Enterprise Resource Planning) system.

Overview of the Mobile Mill Management System

One embodiment of an administrative program for mobile mills is shown in Figure 1. A central administrative program receives input from the corporation and from individual mills (shown as Mill A, Mill B, and Mill C). The corporate input can include corporate data such as financial goals, projected product demand, and information about alternative sites that may be available for the mills in question. Optimization criteria can also be provided at the corporate level, identifying what criteria must be met in order to justify a change in the location of one or more mills, or a change in the mix of products and their quantities. The criteria can also include constraints that may reflect legal agreements, regulatory barriers, and the like.

The information from each mill can include data on historical, current, and projected conditions pertaining to raw materials, power supply (e.g., cost and reliability of electrical power or fuel), regulatory burdens (e.g., anticipated banning of a byproduct or raw material, or cost of meeting a proposed regulation), logistics (e.g., shipping costs for providing products to a distribution center), labor supply, market factors, and other factors. Production details for each mill can include information on the range of grades that can be made, the quality of the products, the rate of production, runnability (e.g., machine downtime and typical waste levels), landfilling or effluent needs, manpower required, production cost per unit, and so forth. The representation and projection of data can be performed in many different ways, such as data look-up tables, statistical correlations, neural networks, fuzzy logic, and the like.

The administrative program can receive and store information from each mill at its current location and estimate parameters for alternative locations. Permutations in the geographical distribution of the mills and the product mix from the mills (including intended customers) can be considered in calculations to determine if modifications to the current arrangement would better meet corporate criteria and enhance profitability or achieve other targeted goals specified in the optimization criteria.

The proposed modifications from the administrative program may be reviewed by humans or another program, and the proposed change, if approved, may result in a signal being sent to the involved production sites to order a change in equipment and cause the appropriate components to be relocated according to a schedule provided by optimization software or a human. Work orders or purchase orders may be issued automatically to cause the proposed modifications to happen rapidly. The relocated components can then be installed and monitoring of production and other factors continues until another relocation order is justified.

The allocation of mobile mills, resources for the mills, and the distribution of products or quantities of products produced at each mill can be optimized for given conditions using any known method, such as linear programming, mixed integer programming, neural networks, genetic algorithms, evolutionary programming, genetic programming, mixed integer nonlinear programming, simulated annealing, tree annealing, and the like. Reactive search algorithms can also be employed, as discussed on the "Reactive Search Homepage" of Robert Batiti at (Dec. 10, 2002). One example is the Reactive Tabu Search (RTS) algorithm, described by Robert Battiti and G. Tecchiolli, "The Reactive Tabu Search," ORSA Journal on Computing, 6(2):126-140, 1994. Other tools such as neural networks can also be applied to optimize resource allocation.

In one optimization approach, the conditions at multiple mills are scanned, and trends are used to predict future conditions, which are then considered in optimizing resources in light of lag times for moving mills, changing product grades, establishing new locations for moved mills, and the like, such that the process of implementing a change is started early enough to have the change completed in time to meet the predicted new conditions.

Minimills figure: organization chart showing relationships, with administration of minimill (mobile mill) resources.

Figure 1. Overview of a Mini-mill Optimization System

In another version of the system, a computer algorithm for managing the relocatable assets repeatedly monitors market demand and other factors, and compares the external factors to the production capabilities and performance of two or more mills that are participating in the relocatable equipment system. Cost of moving the assets and the downtime associated with a grade change or production site change is factored into a cost/benefit analysis to determine the optimum location of the components. For improved flexibility, more modules of a given class than the number of production sites may be desired to permit one module to replace another without causing down time at another machine.

Political factors can be considered in the optimization and decision making process. For example, suppose that a company producing articles in mobile plants in several countries in a region receives information regarding the potential outbreak of civil war in one of the countries. A risk factor can be determined, or, if the information is reliable, a criterion can be set to indicate that the factory must be moved out of the at-risk country. A variety of alternate locations can be then be explored, with the administrative program automatically considering the logistics, raw material costs, and other factors pertaining to alternative sites, in order to optimize the new site for the mill or to make a decision that the mill should be shut down for the moment. In some scenarios, the need to move one mill may result in an optimum solution in which multiple mills may need to be shifted to obtain the best return on investment. The optimization process can be constrained to only consider a subset of the related mills in the relocation proposals offered.

In addition to better responding to changing markets, economic factors, political situations, and so forth, relocatable production facilities could be employed to achieve other advantages, such as synergy between different types of mills. For example, some absorbent articles such as diapers or feminine care products may require high-bulk tissue components or airlaid webs produced at distant facilities and shipped at relatively high cost, due to the high bulk, to the production facility for the final product. A relocatable mini-mill for tissue or airlaid webs could be installed in the vicinity of the absorbent article production facility to eliminate the high shipping costs. Similar considerations can apply to many other materials used in the production of final articles. Such materials can include nonwoven webs, tissue and paper, films of all kinds, glass, metals, chemicals of any kind, textiles, foams, and the like. Other materials could be provided without the need for dehydration as an intermediate step prior to shipment.

The relocatable production facilities can include modular mini-mills or relocatable modular components of a full-sized factory. Relocatable components are physically movable to another production site and can be moved to various sites in a manner that optimizes economic returns (e.g., produces a paper grade near the region of highest demand to reduce transportation costs). Entire mills or simply components of the mills can be installed and moved to optimize production (or meet regulatory demands). Similarly, a plurality of papermaking or absorbent article technologies can be relocated to various mills to optimize production strategy. Mobile mills may also be placed near fixed production facilities used to provide raw materials, packaging materials, or related products for combined packaging. Likewise, mobile mills for a final product such as diapers may be located near a fixed mill providing raw materials such as fluff pulp or tissue.

Components of the modular mill may be relocatable by means of rail, truck, barge, and the like, and can include components that remain mounted on a rail car or platform adapted for rapid loading and unloading from a rail car. Mill components can be installed on a standardized track system embedded in the foundation with attachment means to temporarily anchor the component to the foundation. For example, brackets or flanges may fixedly mount the relocatable device to spaced apart receiving mounts embedded in the foundation for stabilizing the components. Alternatively, the components may be mounted to fixed or movable frame members that are firmly joined to the foundation.

Integration with Other Software Systems

A mobile plant administrative program may be integrated with Enterprise Resource Planning (ERP) systems. Exemplary ERP systems include those marketed by suppliers such as SAP (Newtown Square, Pennsylvania), JD Edwards (Denver, Colorado), Manugistics (Rockville, Maryland), Siebel Systems (San Mateo, California), ROI Systems (Minneapolis, Minnesota) including the MANAGE 2000 brand pre-recorded computer programs, or custom built systems. An exemplary tool for integrating mobile plant information with ERP systems (SAP R/3 systems in particular) and generating financial reports is DATA INTEGRATOR of Business Objects Americas, Inc. (San Jose, California). Other ERP software that can be adapted for managing mobile production facilities includes Adonix X3 of Adonix, Inc. (Sewickley, Pennsylvania).

Management of mobile production facilities also can be integrated with manufacturing executions systems (MES) for matching production of goods to the demand for goods and for aligning production commitments with production resources. MES suppliers include CIM-MET of Robesonia, Pennsylvania, and Fronstep of Columbus, Ohio. Exemplary software for scheduling and manufacturing execution includes the products of nMetric Corp. of Costa Mesa, California

Existing software and known methods may be used to determine the financial costs associated with production at multiple mobile plants, including the impact of regulatory burdens, logistics challenges, and other region-specific factors. A computer system for determining the financial cost of various production problems and process bottlenecks is disclosed by Van Der Vegt and Thompson in U.S. Pat. No. 6,144,893, issued Nov. 7, 2000, and in U.S. Pat. No. 6,128,540, issued Oct. 3, 2000. Columns 1 to 12 in U.S. Pat. No. 6,144,893 disclose the computer method, and columns 12 to 19 therein disclose a method for generating a problem priority table for problems in the process. The determination of the cost of a process problem may be calculated based on whether the process is constrained by production limitations or whether the process is sales constrained (demand for the product is less than the maximum capacity of the machine).

Integrated systems, in which mobile plant administration and other systems tie into purchasing and financial systems, may be used for many purposes. Production data and other information from mobile mills may be combined with financial reporting tools, components, or modules as well. Numerous data mining techniques, including but not limited to neural network and fuzzy logic analysis, may be applied to the information and used to optimize profitability and improve process control, identify weaknesses in systems, parts, or vendor performance, and so forth. Results may be displayed on a web page to local or remote viewers (typically authorized viewers only); displayed via a client (e.g., through a window on a monitor for a Human-Machine Interface such as WONDERWARE brand manufacturing and process control operator-machine interface software); incorporated into weekly, monthly, and annual reports; used to guide daily operations; and so forth. Production and profitability results may be sorted and/or displayed according to sector, machine type, product classification, geographical location (to examine the effect of a proposed change in mill's location), technology or raw material types used in production, and the like. In generating reports, any suitable type of chart or graph may be used, and results may be put into any suitable software format.


Manufacturers are expected to increasingly consider the benefits of mobile mills, especially in regions of the world with higher risk or uncertainty in market conditions, currency, socio-political status, and regulatory setting. Computer-assisted methods of tracking pertinent information and optimizing mill allocations and production plans may be useful tools in best using mobile mills or mobile production modules in permanent mills.

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