Good Production Plan Research Articles

The Virtual Shipyard: A Simulation Model of the Shipbuilding Process

This paper describes a unique software program that simulates the dynamic complexities of the ship construction process. The program, called ShipBuild™, was developed by Decision Dynamics, Inc. (DDI) under a Small Business Innovation Research (SBIR) contract sponsored by NAVSEA. The program greatly simplifies the planning and replanning process, making it easy to create a good production plan and keep it current. This simulation model of the shipyard production process captures both the essential physical shipbuilding activities and the essential management decision making activities that support the physical production processes. The application consists of two independent submodels, a simulation capability and a results viewer component. The first submodel identifies the overall shipyard facility and manpower resources and the second identifies the construction tasks required to build a ship. The submodels interact to calculate the specific allocation of resources over time necessary to produce the ship. The output generated from the program provides the durations and manhour loadings of elements of the ship construction process based upon dynamic resource availability. The output (unlike other scheduling programs for which durations are typically input and resource allocations an output) provides both schedule and resource use. Task durations are calculated based upon the manhour requirements, the number of people assigned and their productivity. Output generated by the application can assist Program Managers and Design Engineers in analyzing the manhour cost and schedule impacts of alternative designs and construction sequences. The program can also help to quantify the cost and schedule impact of delay and disruption as well as assist in identifying the most effective management actions to overcome such problems.

A case study in FMS production planning and dispatching

The speedy development and extensive application of computers have helped play a significant role in a new technological revolution. The importance of FMS flexibility in producing a variety of products and adapting rapidly to customer requirements makes FMSs attractive. Further, FMSs are most appropriate for largevariety and medium- to high-volume production environments. However, the module of the FMS production planning system is not perfect. This paper focuses on a new scheme for FMS production planning and dispatching under the realistic assumptions promoted by a particular flexible manufacturing factory. Some practical constraints such as fixture uniqueness, limited tool magazine capacity, and a given number of pallets are considered. The simulation results indicate that the scheme provides a good production plan, according to the short-term plans from the MIS Department. Some conclusions are drawn and a discussion is presented.

A transition planning method applied in a decision support system for potplant nurseries

In the Netherlands, some thousands of glasshouse nurseries produce potplants. The design of a good production plan is often a complex problem, because of the great number of different types of potplants and their varying requirements for space and labour during the cultivation process. During the last six years a decision support system was developed. Researchers and practitioners cooperate closely in this project. It is possible to characterize the developed model by the name ‘transition planning’, because the essential operation optimizes the transition of the firm's present production scheme towards a desired production scheme. The computerprograms are divided into programs for simulation and for optimization of production plans. The decision support system, implemented on several types of microcomputers, is already in practice in a number of potplant nurseries. Improvements of the net financial results of about ten percent have been reached.