Milling like the masters

At the beginning of 2019, renowned milling machine manufacturer Kunzmann relaunched its line of manually operated universal milling machines, which are particularly popular in vocational training and workshop production. With B&R technology and integrated safety functions such as Safe Brake Test (SBT), Kunzmann was able to reduce axis switching times, save space in the control cabinet and make the machines easier to install and service.

At the end of August 2019, more than 1,600 young trade professionals gathered in the Russian city of Kazan to put their talents to the test at the WorldSkills competition. The world's best millers were crowned in the categories "Polymechanics and Automation", "Manufacturing Team Challenge", "Prototype Modelling" and "Industrial Mechanics Millwright". The competitions were conducted using fifteen WF 410 M milling machines provided by renowned German machine tool builder Kunzmann.

Like its big sister, the WF 610 M, this machine is 100% manually operated. They are known for their long service life, high machining precision and advanced safety features as well as being ergonomic and easy to operate. This makes them perfectly suited for training, prototyping and workshop production. They are standard equipment at many vocational schools and apprentice workshops, but also at many machine tool builders, mold makers and manufacturing OEMs.

Kunzmann implemented numerous improvements when it revamped its milling machines in early 2019. Among them was a switch to a new drive supplier. "B&R prevailed over other providers with its innovative solutions and an attractive price/performance ratio," says Ralf Guthmann, head of electrical design at Kunzmann. "They also scored points early on with their excellent consulting expertise." B&R employees were able to answer the majority of Kunzmann's questions off-the-cuff during initial exploratory discussions. "That's quite different than experiences we've had in the past," reports Guthmann, "In some cases, they had to send as many as four employees to visit us to achieve the same thing. And what B&R presented to us was a quantum leap compared to the previous solution."

Kunzmann experts were very pleased with how B&R's application engineers handled the tasks of selecting the components, sizing the drives and programming the PLC. But that's not all. B&R also assembles the milling machine control system, comprising twelve X20 modules, then installs the software, labels the station and finally tests it. "We then purchase a package that includes all the B&R components we need for six machines at a time. That's a significant relief for our internal ordering, assembly and testing processes," says Guthmann.

Last but not least, the change of supplier and the new automation technology from B&R have also made the manual milling machines easier to service and maintain. "The X20 modules consist of three modular components, so it is possible to replace just the terminal block, electronics module or bus module without having to dismantle the rest of the system. It's a really well thought-out solution." Kunzmann can also access the web server of the X20 PLC directly from the Heidenhain controller's integrated web browser to retrieve diagnostic data from B&R's System Diagnostics Manager (SDM). This makes it possible to perform remote maintenance on both the Heidenhain controller and the B&R system via the TNC128's TeleService. "We don't need another PC on site for this and don't have to install any special software or program anything," says Guthmann. B&R's SDM delivers data about the current state of the drives, such as the current speed, position and controller enable values. It is also possible to open and operate the oscilloscope integrated in each drive via SDM, or use its I/O viewer to display the current states of all the I/O channels in the B&R system. This shortens commissioning times by eliminating the need for time-consuming I/O wiring tests.

For Kunzmann, the bottom line is that introducing B&R technology has made it easier to ensure the high level of safety that users have come to expect from their milling machines, while giving them unprecedented design freedom and making the machines much easier to install and maintain. For users, the transition was a seamless one. "Since shipping the first pilot machine in the fall of 2018 we haven't received a single bit of negative feedback. That's a good indication we did everything right."