How can existing machines be digitalized and connected quickly and easily?
How do I obtain important performance indicators to optimize my system availability and process quality without intervening in the existing automation? An example project from our plant in Homburg shows how quick and easy it can be to gather data for Industry 4.0 applications and transfer it to higher-level systems.
Making existing machines transparent
Machines without connectivity are like a black box. There is an input and an output, but we know nothing about the processes taking place inside.
However, making these machines — of which there are millions in Germany alone — transparent and thus laying the foundations for Industry 4.0 does not necessarily mean intervening in the existing automation. The Bosch Rexroth plant in Homburg has demonstrated how it can be done.
Example from production
The products from Homburg in Saarland include valves for the working hydraulics of mobile machinery such as tractors. Once machining centers have created high-precision channels and holes in the cast blanks, they are cleaned. Fully assembled, the valves are manually synchronized with the electronics and tested for leaks on test benches. Despite previous cleaning, metal particles, chips, or water residue can get into the hydraulic oil and cause subsequent damage to the test benches or test samples. So how can the threat of plant shutdowns due to contaminated hydraulic oil be avoided?
From planned maintenance…
There was an urgent need for action, as in the long term plant shutdowns due to hydraulic oil contamination accounted for around 25 percent of failure costs on average. The previous strategy was planned maintenance. The filter media were exchanged at fixed intervals—regardless of the contamination level—and this process was documented manually. However, it is obvious that this kind of planned maintenance is effective but uneconomical. But what is the alternative?
…to condition-based maintenance
In conjunction with a team of specialists drawn from the entire Bosch Group, Bosch Rexroth connected a ten-year-old test bench retroactively with the Rexroth IoT Gateway and used a range of Bosch IT tools to install a comprehensive condition monitoring concept to continuously monitor the condition of the filters and the oil quality. In case of irregularities, maintenance is automatically initiated using an integrated ticketing system.
IoT Gateway collects sensor data
The key component for data collection and transfer is the IoT Gateway developed by Bosch Rexroth, which acquires the data from the retrofitted sensors, particularly the difference in pressure before and after the oil filter, as an indicator of the level of contamination of the filter cartridge. Further sensors detect the size and number of particles, monitor the temperature, and record the level of dissolved water in the hydraulic oil.
Plug & Run: Connected in only four hours
The classic method of modernizing the testing plant—including sensor connection, interfaces and classic PLC programming—would have taken the specialist team a week. Simplified commissioning using the IoT Gateway reduced this time to just half a day. Instead of programming knowledge, the web-based configuration software only demands a few parameters and checks from the user. The bottom line is that the engineering effort required for modernization of the test bench was reduced by 90 percent.
IoT Gateway and Production Performance Manager (PPM)
The IoT Gateway hardware is based on an industrial-suited XM21 controller from Bosch Rexroth. Certified for reliability and durability, this hardware is an open system that supports a large number of sensors and data sources from various manufacturer, e.g. analog and digital sensors, data from external controllers, or OPC UA based data sources. In Homburg, the Gateway sends the collected and internally translated sensor data to a server on which the Production Performance Manager (PPM) production information and analysis system from Bosch Software Innovations is installed. This system acquires the production and machine data from the connected test bench almost in real time, merges the information into a single visualization, and forwards specified events to predefined persons.
Scalable package: IoT Gateway and PPM
Once the Production Performance Manager is installed, a number of IoT Gateways can be connected to it. The two components are now also available from Bosch Rexroth as a complete package. In Homburg, the maintenance department uses the bundle to intervene before critical failure conditions occur.
Automatic spare parts ordering
They also use Production Rules Configurator (PRC) from Bosch, which uses graphically modeled rules to monitor compliance with the specified parameters. This enables users to specify when a maintenance, a filter or an oil change is necessary, without the need for any IT or programming knowledge. A Maintenance Support System has also been implemented as a link between the software modules for the networked machine and the plant’s ERP system. This digitally maps the ordering of filter media and spare parts stock.
Significant improvements in OEE
Within the first few months, the project showed significant improvements. In terms of process quality the retrofitted test bench can now provide documented data on the purity of the oil, which would previously have had to be analyzed using a complex manual process. Rule-based condition monitoring with predictive maintenance reduces down times and increases the Overall Equipment Effectiveness (OEE) of the pilot test bench by five percent. Failure costs fell by 25 percent. The Return on Investment (ROI) has been calculated at less than 1.5 years. The main reason for this is an OEE optimization through reduction of unscheduled machine stops.