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Wärtsilä: Plant Simulation

Wärtsilä: Plant Simulation

Wärtsilä Netherlands BV in Drunen designs and produces ship propulsion systems. In 2008 the company increased its production capacity to meet rapidly growing demand. Investments such as these are prompted by logistic needs that cannot be satisfactorily met by existing processes. A pilot project was set up to simulate processes with the Tecnomatix Plant Simulation tool developed by Siemens Industry Software. cards PLM Solutions BV taught Wärtsilä employees how to use the simulation software and provided assistance. The results showed that the introduction of a pull production process would radically reduce lead times and that adjustments needed to be made in the foundry to achieve the desired output.
 
Business case
 
An enormous increase in demand for propulsion systems over a period of several years exceeded Wärtsilä’s production capacity. Broadly speaking, the process of producing an adjustable screw system can be divided into three stages: the casting of the propeller blades and hub components, machining and assembling. The machining processes were the main bottleneck at the production plant in Drunen so the company planned to implement a series of investments. 
Each propulsion system produced by Wärtsilä is unique and every system is adjusted on board the ship. In this engineer-to-order environment routing and processing times differ from one order to the next and production lead time is invariably long. Wärtsilä’s production engineers had various ideas about how to reduce the lead time and minimize the amount of work in hand and wanted to use simulation to predict the effect of the new planning strategies.
 
Process simulation
 
Simulation involves the creation of a realistic model of production processes in order to analyze all kinds of scenarios. It is a powerful tool that can be used to make strategic decisions, especially if the dynamics and complexity of the production process are significant or if a virtual situation needs to be optimized.
 
Project
 
Together with cards PLM Solutions Wärtsilä identified the aims of the project. These were to increase production capacity and reduce production costs. The company planned to achieve this by expanding the capacity of the machinery and reducing the lead time. Wärtsilä wanted to use a POLCA or CONWIP production control system to implement a quick response manufacturing (QRM) solution that would reduce production lead time from six months to just a few weeks.
cards PLM Solutions taught two Wärtsilä production engineers how to use the software to conduct simulation projects. First they created a production model of the foundry and mechanical engineering plant. There was a large buffer of rough cast components between these two departments. Including the foundry in the model made it possible to perform an accurate analysis of the movement of the buffer of components. As well as the machinery the simulation model also included the operators, shift schedules and robots. So the behavior of the model replicated reality. The model was fed with data, such as production times, production routings and the expected product mix in the years to come.
 
Unexpected insight
 
Having created and validated a model of the existing situation the engineers then expanded the model with the addition of QRM principles using POLCA and CONWIP production control systems. A simple dashboard enables the user to plan simulation scenarios and select the right parameters. From the start the experiments showed that the planned expansion of the capacity of the mechanical engineering plant, which was already being implemented, was critical in aligning capacity with the foundry output. The experiments also showed that the lead times could be reduced to just a few weeks. Yet the model indicated that increasing capacity would not make it possible to increase the total production volume to the desired level. This paradox led to a more detailed analysis and the model was used to identify possible causes.
When the model would not produce the desired production volume, the project team initially concluded that there must be a bottleneck in the process. Yet an analysis of capacity utilization rates showed that none of the machines were being overutilized and none of the buffers in the system were full. Nor were there any strange outliers in the lead times of individual orders. In other words, the model indicated that the mechanical engineering plant was producing the parts presented by the foundry. This meant that the source of the problem had to be in the foundry. A series of additional experiments showed that the foundry itself would become a bottleneck in the near future: the reach of the sand mixers was insufficient to fill the desired number of molds. The results of the simulation gave Wärtsilä an insight into the investments it needed to make to be able to meet demand in the years to come.
 
Results
 
The simulation project showed Wärtsilä Netherlands BV the most effective way to increase capacity and also enabled the company to avoid pointless investments. The shorter lead times have reduced the amount of work in hand and given the Procurement Department more time and flexibility that can be used to achieve additional costs savings.
Simulation gave Wärtsilä greater insight into its own processes and also helped the company to communicate these insights.
 
www.wartsila.com