For the Siemens AG Energy Sector, a supplier of products, solutions and services for power generation, transmission and distribution, as well as for the production, conversion and transport of oil and gas, Plant Simulation software allowed them to lower costs and eliminate bottlenecks - all before construction of a new manufacturing plant began.
Siemens Energy's High Voltage Products business unit, part of the Power Transmission division, manufactures conduits for circuit breakers that are considered the centerpiece of all switching stations. These conduits are made of fibre-reinforced polymers created by hardening a mixture of epoxy and fibre optics, or aramid, which is typically used for bulletproof vests.
To improve its position in the global energy market, Siemens Energy Power Transmission decided to increase its manufacturing capacity by building an entirely new conduit manufacturing plant in Berlin, Germany. The purpose of this plant was ambitious: to manufacture conduits that are significantly longer and have greater diameters than the previous versions.
To accommodate the new dimensions, a new, automated thread winding process would be needed to replace the old manually organized vacuum method. The new facility and machinery would allow the company to manufacture conduit more cost-efficiently and also improve quality.
In the course of building the new plant, manufacturing planners at the Siemens Energy offices in Berlin took advantage of the Plant Simulation solution in the Tecnomatix portfolio from Siemens PLM Software. This software makes it possible to simulate and optimize material flows and resource utilization. It also enables offline analyses of production system components, as well as evaluations of different what-if scenarios.
The new conduit production method was a pilot project, which meant that manufacturing planners had to design a complex, highly interlinked production process and ensure that annual target quantities would be met, without any comparable experience to guide them.
"Surely we would have been able to plan the plant layout with conventional methods," explains Yasin Vardar, a manufacturing planner with Siemens Energy and the main Plant Simulation software user on this project. "Without Plant Simulation, we would have never been capable of determining production quantities."
Indeed, the software solution was critical to the success of the new facility.
Siemens PLM Software partner, Frankfurt, Germany-based SimPlan AG, helped create the simulation models. Having already optimized many material flows using the Plant Simulation solution in the Tecnomatix portfolio, SimPlan brought a wealth of experience to the project. Arne Frenkel, project manager at SimPlan, implemented the simulation model on-site while at the same time training Vardar in the use of the software.
"We assist our customers from initial purchase considerations to routine application of simulation during operations," says Frenkel. "The use of Plant Simulation helps make certain that the manufacturing planners will achieve their ambitious goals."
Simulation and optimization of complex material flow
To create the simulation model, all automated portions of the proposed plant were modelled digitally. This included the mandrels (the tools on which conduits are made), the winding machine (whose spools wind plastic threads onto the mandrels), the pre-hardening furnace, and the conduit removal machine, as well as the tempering furnace in which the conduits are hardened.
To define material flow, the planners had to consider several parameters: number of tools, availability of machines, speed of transportation systems, cycle times, manpower requirements, control of the furnaces, and so on. In addition, three types of conduits requiring different materials with different hardening times were going to be manufactured.
"With Plant Simulation, we were able to incorporate a variety of interacting variables in a single model," says Vardar.
Delivering clear business value
Plant Simulation made a clear and significant difference in terms of added business value. One simulation showed that one of the three initial chambers of the tempering furnace could be eliminated through the use of an intelligent buffer concept for pre- and post-transportation tracks. The furnace had not been purchased when the simulation was run, so it was possible to modify the order accordingly.
"In this situation, Plant Simulation helped us avoid significant capital investments and operational costs," explains Vardar.
Another optimization involved the control of the start of the tempering furnace. Simulations of the planned start times led to a strategy that showed that it is more efficient to turn the furnace on when it is fully filled with conduits rather than at the end of each shift. This small change would lower energy costs. In addition, simulation helped planners identify the optimum number of mandrels. And by evaluating in detail the cooling phase of the tools, simulations were able to make significantly more precise predictions than previous calculation methods. As a result, unnecessary overcapacity was avoided.
The digital model also revealed that the original cycles of the pre-hardening furnace led to congestion at the winding machine. A cycle change eliminated that blockage and ensured a continuous mandrel supply. The planners also saw that the speed of the transportation system was too slow throughout the entire material flow.
"Using Plant Simulation was a key to the success of the entire project. It's hard to imagine how we planned previously," says Vardar.
Even now that the new plant is operational, manufacturing planners at Siemens Energy still benefit by using Plant Simulation. As a "living virtual model," the software helps determine the right manpower requirements for different quantity scenarios, and also helps in organizing shift work. The company is now considering the use of Tecnomatix for digitally modelling and optimizing manufacturing processes at other, older plants.
This article originally appeared in the March/April 2012 issue of Manufacturing AUTOMATION.