Scheduling (production processes)

Scheduling is an important tool for manufacturing and engineering, where it can have a major impact on the productivity of a process. In manufacturing, the purpose of scheduling is to minimize the production time and costs, by telling a production facility what to make, when, with which staff, and on which equipment. Production scheduling aims to maximize the efficiency of the operation and reduce costs.

Production scheduling tools greatly outperform older manual scheduling methods. These provide the production scheduler with powerful graphical interfaces which can be used to visually optimize real-time work loads in various stages of production, and pattern recognition allows the software to automatically create scheduling opportunities which might not be apparent without this view into the data. For example, an airline might wish to minimize the number of airport gates required for its aircraft, in order to reduce costs, and scheduling software can allow the planners to see how this can be done, by analyzing time tables, aircraft usage, or the flow of passengers.

Companies use backward and forward scheduling to allocate plant and machinery resources, plan human resources, plan production processes and purchase materials.

Forward scheduling is planning the tasks from the date resources become available to determine the shipping date or the due date.

Backward scheduling is planning the tasks from the due date or required-by date to determine the start date and/or any changes in capacity required.

The benefits of production scheduling include:

*Process change-over reduction
*Inventory reduction, leveling
*Reduced scheduling effort
*Increased production efficiency
*Labor load leveling
*Accurate delivery date quotes
*Real time information

cheduling Algorithms

Heuristic algorithms

Production scheduling can take a significant amount of computing power if there are a large number of tasks. Therefore a range of short-cut algorithms (heuristics) (a.k.a. dispatching rules) are used:
*Modified due date scheduling heuristic
*Shortest processing time scheduling heuristic
*Earliest due date scheduling heuristic
*GreedyET scheduling heuristic
*Shifting bottleneck heuristic
*Minimum slack heuristic
*Apparent tardiness cost scheduling heuristic

tochastic Algorithms

*Genetic Algorithm Scheduling

References

* Blazewicz, J., Ecker, K.H., Pesch, E., Schmidt, G. und J. Weglarz, Scheduling Computer and Manufacturing Processes, Berlin (Springer) 2001, ISBN 3-540-41931-4
*Herrmann, Jeffrey W., editor, 2006, "Handbook of Production Scheduling," Springer, New York.
*McKay, K.N., and Wiers, V.C.S., 2004, "Practical Production Control: a Survival Guide for Planners and Schedulers," J. Ross Publishing, Boca Raton, Florida. Co-published with APICS.
*Pinedo, Michael L. 2005. "Planning and Scheduling in Manufacturing and Services," Springer, New York.

ee also

* Manufacturing process management
* Advanced planning and scheduling
* Timebar Scheduling

External links

* [http://www.productionscheduling.com Production Scheduling Portal] News, articles, resources and software.
* [http://www.planningengineers.org/software/ Planning Engineers Organisation] Details all known production scheduling software.
* [http://www.planningplanet.com/ Planning Planet] PlanningPlanet provides online resources, networking and self-help for Planning, Scheduling & Project Controls Professionals.
* [http://www.asap.cs.nott.ac.uk/iol/is-network/links.shtml University of Nottingham. Inter-disciplinary Scheduling Network] Research groups, scheduling link directories and a directory of scheduling suppliers.
* [http://www.taylor.com/ The Taylor Group] The Taylor Group has been implementing advanced planning and production scheduling solutions with manufacturers around the world since 1989.

Open source solutions

* [http://www.erp5.org ERP5]
* [http://rtime.felk.cvut.cz/scheduling-toolbox TORSCHE Scheduling Toolbox for Matlab] is a freely available toolbox of scheduling and graph algorithms.
* [http://www.frepple.com frePPLe] is a toolkit for building production planning solutions.