How can you quickly and dramatically reduce electricity consumption within heavy industrial manufacturing? In today's article, I will look at a case published by Siemens Digital Industries, where a major engine manufacturing unit within BMW managed to save three million kilowatt hours per year on one of its production lines. The secret: PLM and digital factory simulation.
The issue of energy savings is extremely topical. First, consumers and regulators are demanding greener products every year. Second, electricity prices in Europe are skyrocketing as a result of Russia's war of aggression against Ukraine. Finally, there are the effects of climate change and the world’s goals to radically lower energy consumption and reduce CO2 emissions. Electricity-intensive industries, such as automotive manufacturing, have been particularly affected by all of these factors—with a vision of the industry going net-zero by 2040, according to COP26.
Overall, there are two ways to achieve zero-emissions: reduce/offset the contributions from the transport sector and reduce/offset the emissions from manufacturing itself—preferably to the point of neutral climate and environmental impact. The question is how to move forward?
Even if electric cars gradually take over, fossil-fueled vehicles will continue to be manufactured for a number of years. These will partly be "pure" petrol or diesel engines, as well as hybrid solutions with mixed electricity and fossil fuel operation. And then there will be fully electrical solutions—which have different manufacturing content than their more complex internal combustion counterparts. During this time, and regardless which powertrain is in use, the principles of digital factory optimization can be used. In this regard, BMW's production in Steyr, Austria is an excellent example of how to optimize energy in advanced manufacturing processes.
Automakers manufacture many of the core parts and components of their engines in-house. Crankcases, crankshafts, cylinder heads and connecting rods are turned, milled, drilled, ground and honed on sophisticated production and transmission lines at facilities such as BMW Motoren GmbH in Steyr, the largest engine plant within the BMW Group. Manufacturing engineers throughout the group use the Tecnomatix portfolio from Siemens Digital Industries for plant simulation.
With the help of the Plant Simulation solution in the Tecnomatix portfolio, complete production lines with machine tools and robot cells, as well as material handling and transport systems, are designed and simulated.
Part of Siemens PLM Portfolio Xcelerator
The Plant Simulation module is part of the Siemens PLM portfolio Xcelerator, where Teamcenter is the data backbone for product data and Tecnomatix supports the management of digital manufacturing control. In Xcelerator, there is generally a series of seamlessly communicating apps that tie together state-of-the-art product development. This includes everything from the initial requirement specifications around a product via design tools, to manufacturing-related software such as Tecnomatix.
The latter tools offer opportunities to sharpen and optimize the production process—for example, by rearranging the layouts on the factory floor. The trick is to do this digitally instead of physically. By simulating the manufacturing arrangements digitally, one can reach the optimal structures from a number of different perspectives without adding much cost. In addition to including energy consumption as a parameter, there are several others which can be selected such as speeding up production cycles and saving investment costs through optimized tool and machine utilization.
The Plant Simulation solution in the Tecnomatix portfolio is in common use among German vehicle manufacturers, because it contains a kit of powertrain parts developed by the German Automobile Manufacturers Association Verband der Automobilindustrie e.V. (VDA). In BMW's engine manufacturing plant in Steyr, Plant Simulation is used for the planning of the whole plant from personnel to each piece of machine.
Optimizing Energy Efficiency at No Extra Cost
Siemens’ case study notes that the number of versions in which cars are available has changed dramatically in recent years. What used to be a business based on mass production has increasingly come to be based on customized configuration.
These trends indicate that more versions of the same basic solution mean lower quantities of each. At the same time, no manufacturer wants the introduction of a new component to require the creation of a whole new production line. Instead, the capability of existing production lines is maintained as far as possible while still being able to cope with changing requirements. In the most advanced production technology solutions, this can even be managed by replacing or adding connectable units, such as new or greatly changed processing centers.
The BMW engineers in the Steyr factory faced some of the latter problems a couple of years ago when a line producing crankcases was modified to handle a growing demand for smaller engines. “Many new machining centers were added. The high-pressure pumps in the basement needed to address this new challenge in order to supply sufficient cooling lubricant. At the same time, within the production line equipment dedicated to components for 6-cylinder engines was not used to capacity,” reads the case study.
A New Version of Plant Simulation Paved the Way
Around the same time, a new version of the Plant Simulation software became available, with new features for energy analysis. With this, the traditional scope of use for plant simulation models was expanded to optimize throughput, alleviate bottlenecks and minimize work in progress.
“Available without additional fees in all license configurations, the software provides dialog boxes for setting wattage values for various modes of operation such as working, setup, operational, standby or off for all simulation entities, as well as the time required for changing from one state to the next,” Siemens writes in the case story.
The simulation model can thus be used to reveal load imbalances, optimize individual machine use or streamline spare parts logistics. Siemens claims in the case study that with this feature, energy savings can be easily achieved, “as even simple measures such as actively changing to standby rather than awaiting the timeout often show remarkable results.”
Modification of the PLCs
When modeling the existing production line in Plant Simulation, all that was required to obtain a relevant energy simulation was to map power consumption of each machine in the line and add the production steps in the process control system to the existing simulation model.
It only took the engineers at Steyr two weeks to obtain presentable results.
Based on the energy simulation, where the Steyr plant was assisted by the German simulation specialist company iSILOG GmbH, various scenarios were tested in the virtual production model that had been created with Plant Simulation.
In the simulation model, modifications to the existing programmable logic controller (PLC) for machines within the line were predicted to provide energy savings of 1.66 million kilowatt-hours of electricity on the shop floor. This became exactly what was achieved in the physical plant after the maintenance technicians reprogrammed the PLCs.
Since an idling machine does not need to be supplied with cooling lubricant, the plant saved an additional 1.4 million kilowatt-hours of electricity by shutting down some of the high-pressure pumps at the media supply facilities.
An Investment Well Worth Considering
In the case study, Siemens summarized the important energy consumption gains. “Implementing the auto start-stop function in the crankcase line as an energy-saving measure not only led to a total energy reduction by 3 million kilowatt hours of electricity per year, but it also showed a favorable side-effect: if machines or supply pumps are turned off while they are not needed, this also reduces noise.”
Reduced energy consumption in connection with electricity-intensive manufacturing is something that is very timely, and may be well worth considering. It is easy to see the power of production optimization via simulation and what it can do to contribute to reduced electricity consumption, lower costs and improved sustainability.