Aldersbach plant. Factory of the future.

For Franz-Josef Birkeneder, Industry 4.0 is nothing new. “Efficiency has always been the crucial factor as far as we’re concerned. Digitalization makes us quicker and more proactive in our everyday routines. It helps us to cut out handling stages and thus eradicate potential sources of error.” As manager of the Aldersbach plant, which makes disc brakes for trucks as its key product, Birkeneder has for years been developing networks and frictionless communication between machines to ensure that the showcase facility remains a leader in its field. “Our five assembly lines here request the materials they require by themselves. There is no longer any need for people or paper to intervene. That means we can reconfigure each line for a different product eight times a day, more or less seamlessly.”

Process chain from specification to product

The system, which Birkeneder likes to compare to a string of pearls, has been in operation for four years. The process chain now includes everything from automatic ordering of empties and individual production steps to loading the finished products onto trucks – which also arrive at the yard in line with a digital schedule. Patrick Harter, Head of Knorr Excellence, who has strategic responsibility for digitalization at Knorr-Bremse, sees Aldersbach as a good example: “As far as new technologies are concerned, we are in a very strong position.”

Collaborative robot is an ideal solution

The most recent example of the use of state-of-the- art technology is a large robot, which for the last few months has been working hand in hand with humans. “We needed to increase capacity on one of our lines,” explains Alexander Gerauer, technical manager of the Mechatronics unit. “The best solution was this collaborative robot.” Its powerful arm is positioned at the end of a line that produces EAC 2 electronic air treatment systems for a major truck manufacturer. Here, it picks up the 12-kg product, holds it out for an employee, who affixes the model nameplate, then carefully places it into the transport box. “This means we get a robot to perform a task that is not ergonomically ideal for humans. Of course, we could also have used a conventional industrial robot,” says Gerauer. “We already have more than 50 of them working at the plant.” But setting up the interaction would have taken longer and, more importantly, would have required a lot more space. And here at the Aldersbach plant, space is a valuable commodity.

Seamlessly integrated into workflows

Thanks to benchmark analyses, targeted research and a little help from other companies, Gerauer eventually found the appropriate appliance for the task – although it only existed as a prototype application at the time. “Collaborative robots have sensors that take force absorption readings every second,” Gerauer explains. “The robot will stop moving immediately if there is any likelihood of contact with an employee.” It moves comparatively slowly for safety reasons. “But we have adapted cycle times to integrate it perfectly into our workflow.”

Prototypes from the 3D printer

“I like to think outside the box,” says Kaspar Obermaier, team leader Testing, Diagnostics and Prototyping. Plant manager Birkeneder was all for the idea when Obermaier explained the benefits of 3D printers to him in late 2016. Three devices were purchased. “Our two FDM printers build up layers of molten plastic, producing results that are stable and inexpensive. The polyjet printer, by contrast, uses artificial resin hardened with UV light, which results in smoother surfaces.” Each procedure has individual advantages, depending on the application. “We’re still on a learning curve.”

The printers can create prototype components such as silencers, adapters, engine speed sensors, coil carriers, heating grilles or parts for solenoid valves. The 3D printer is also unbeatable for the speed at which it can turn out samples resembling a finished product for customers to examine and test. Even cloning (reverse engineering) presents no problem; this can be highly practical for older replacement parts.

Speedy production with rapid tooling

Obermaier is particularly proud of a small coil. “This engine speed sensor is really quite unique.” Engineers from Schwieberdingen, who test systems for highly automated driving on snow and ice in Arjeplog, needed engine speed sensors with two coils for their trucks. But the series product has only one coil. “So there was a lot of waste with our standard procedure.”

The solution: Obermaier and his team used the printer to build a new plastic construction with tiny extra channels that were better suited to protecting the wire ends measuring just 0.06 mm in diameter. “This enabled us to significantly increase the quality rate.” In future 3D printers will save even more time. “With rapid tooling we could quickly print our own provisional injection molds without the need for suppliers, and then use these in a plastic injection molding machine to produce a number of small-series parts for testing. That would help to speed up. However, says Obermaier, there’s no question of using 3D printers for genuine series production – they’re much too slow. “But development is making rapid progress.”

Proven shopfloor management

Twice a day, a team from production, logistics, quality, maintenance and management convenes in front of a large screen at Aldersbach. “This displays in real time any problem that may have cropped up over the last few hours,” says Harald Ebner, head of the Disc Brake business unit. “Our assembly lines have 18 stations. If a problem persistently occurs on Line 3 at Station 1, for example, we check if the same problem is also showing for the other lines. If this is the case, it is probably caused by the quality of the component being assembled on line 3. If not, the line will have a specific technical problem, or perhaps a defective sensor.” This initial analysis saves a great deal of what is a key resource – time. The production mainframe – “the mother of all things” – carries out statistical analysis on a huge volume of data generated by process monitoring. “We began developing our shopfloor management system in 2011,” says Ebner. “It took several years to bring it to maturity.”

Focus on real-time information

The system organizes every aspect of production: logistics, maintenance, industrial engineering, quality and purchasing. “As many workshops have shown, the most important thing is to have an ongoing dialogue about the current situation. This enables managers and staff to work together effectively to find a solution.” But where does the real-time information come from? “We started to standardize interfaces for machine data ten years ago,” explains Ebner. “All analysis tools are now operated almost like plug-and-play devices.” That’s how, despite increasing complexity and automation, productivity was further boosted.

Overall Equipment Efficiency as key performance indicator

“We never question staff performance – rather we commit jointly to specific operational indicators.” First and foremost there is Overall Equipment Efficiency, a product of performance, quality and technical availability. “This operational indicator provides the basis for the agreed staff bonus.” This means that staff are highly motivated to report failures immediately on a small display and seek support if necessary. “The role of moderator at our shopfloor meetings also changes regularly,” says Ebner. “This has contributed significantly to mutual understanding.”