Digital manufacturing supports leading automotive supplier’s primary initiative
Value stream mapping and material flow simulation lead to more flexible manufacturing
The drive to optimize production costs
The Behr Group is a systems partner for the international automobile industry. Headquartered in Stuttgart, Germany, Behr employs approxi-mately 17,000 people worldwide at 17 development locations, 28 production sites and 12 joint ventures. Specializing in automotive air conditioning and engine cooling systems, Behr is one of the world’s leading manufacturers and suppliers of original equipment for passenger and commercial vehicles.
Behr’s engine cooling division designs and manufactures complex systems while making certain that each and every brand and type represents a cost effective solution for its customers. In addition, as Behr is a key supplier in the automotive industry, the company faces increasing cost pressures and is always looking for ways to optimize its productions costs.
Manufacturing process flexibility is a crucial parameter for enabling Behr to optimize production. Today’s economy demands that Behr increase the number of product variants that it provides. While product complexity rises, the product cycle times for engine components, which were already very short at 12 to 24 months, constantly get shorter – mainly because of new or revised conformance regulations, such as the European emissions standard.
The road to digital manufacturing
In 2008, Behr started a pilot project to optimize the manufacturing process for stack plate oil coolers at its Muehlacker site. Traditionally, this site had focused on manufacturing single products with tightly defined product structures. To increase its competitiveness, the company needed to replace its single-product manufacturing systems with more flexible manufacturing systems capable of producing multiple products, as well as products with multiple variants and options.
“We didn’t have much experience with digital manufacturing,” explains Markus Schmidt, process designer for Behr’s stack plate oil coolers. Cut off from ERP and CAD data, he and 12 colleagues had been developing manufacturing plans with table calculation sheets and presentation programs. A pilot program was instituted to facilitate multi-product process optimization using the Tecnomatix® Plant Simulation application within Siemens PLM Software’s Tecnomatix Plant Design and Optimization solution. Plant Simulation enables companies to verify and precisely validate material flow scenarios before the actual production system is physically implemented and launched.
At the beginning of the project, value stream mapping was used to evaluate Behr’s existing manufacturing situation. Using this analysis technique, the project team identified the site’s push control strategy as a primary weakness and recommended that Behr change to a pull strategy. To increase productivity, the product cycle time needed to be shortened, work in progress reduced and unnecessary material buffers ahead of manufacturing equipment eliminated.
The need to introduce fully automated part manufacturing also presented process designers with additional challenges. Previously, Behr purchased cores out of stacked plates and drove them through a degreasing unit. During manual manufacturing, the staff assembles the coolers, fills and controls the vacuum furnaces and performs leak tests on the finished coolers. To facilitate fully automated part manufacturing, these two different systems needed to be combined and the process control had to be calibrated correctly. “The stack plate oil coolers are perfect test objects for changing our strategy for multi-product manufacturing,” says Schmidt. “The number of heat exchanging disks that are used defines the performance of the coolers. As a result, we can produce units that provide adequate cooling for each motor type. Theoretically, numerous variants can be realized in the same way.”
Using simulation to facilitate best-practice processes
Leveraging value stream mapping and the process team’s expertise in equipment utilization and manufacturing, the company’s process designers were able to develop a target model with different scenarios. The process team used Plant Simulation to evaluate these scenarios with respect to productivity and cycle times. The simulation revealed the need for the company to establish a buffer to coordinate the two different process elements. Behr decided to use a FiFo (first-in, first-out) buffer for this task, enabling the manufacturing site to optimize the vacuum furnaces, which had been a critical bottleneck in the manufacturing process.
In-depth adjustments to the simulation model focused on the interface between the automated and manual manufacturing processes. While the buffer is designed for a maximum of 320 parts per type, simulations showed that the optimal number of parts in the buffer should not exceed 200. The value of Plant Simulation became apparent when the results of the simulations were compared against Behr’s traditional planning methodology. In fact, the buffer would have been twice as big as necessary if simulation had not been used.
In the end, the company’s process designers were also able to reduce the work in progress by using simulation technology. In the old push-manufacturing approach, 2,000 parts per type were used in the process chain. Now, after Behr successfully changed to pull manufacturing, it is only 700.
The utilization of the vacuum furnaces has been optimized so that all idle times have been eliminated – except during the required cooling and heating phases. All non-essential buffers have been successfully removed. The product cycle time was significantly reduced as the company established an optimal process for order management. Plant Simulation played a crucial role in enabling the company’s process designers to make the right choices about where potential savings and improvements could be made. Now, complete material flow can be planned in detail and validated precisely through simulation. Furthermore, time consuming and costly launch corrections have been totally eliminated.
Significant daily benefits
Behr implemented the lion’s share of the changes it wanted into its manufacturing processes to produce its stack plate oil coolers. Most importantly, the new optimized processes enable the company to continuously realize productivity and financial gains. “The results justify the deployment of the software; the costs were amortized after a short time,” says Schmidt.
All simulation results have been confirmed through practical use. The reductions in work in progress have decreased capital lockup by several thousand Euros per day, which translates into several million Euros a year. The conversion from push to pull manufacturing and changing production control to optimized FiFo buffers improved process synchronization and reduced cycle times by up to 66 percent. Delivery times are significantly shorter. Behr is now more flexible and able to react faster to customer demands. The company’s new multi-product flexible manufacturing systems enable the production of more variants in less time. With the new approach, Behr is also experiencing productivity increases up to 35 percent.
“By implementing flexible manufacturing systems, we are able to meet demands for more variants in a more relaxed manner and adjust quicker to new situations,” explains Juergen Wolf, head of oil cooler process design and optimization, Behr. “The benefits that Plant Simulation generates have noticeably increased the interest in digital manufacturing throughout the company. I am sure that this pilot project is just the beginning, with more process optimization projects in the future.”