Electricity and Control September 2021

DRIVES, MOTORS + SWITCHGEAR

At a glance  BT-Watzke recently integrated a third machine into the painting process for caps that require up to three coats, in order to increase throughput rates.  For Beckhoff, the project involved three individual systems that operate independently but have to run synchronously.  The use of servo drive technology to transport the blanks, rather than a pneumatic solution, was a key optimisation measure in the process.  Collaboration started at the concept phase and enabled an open exchange of ideas and views throughout the project.

[Picture: © Beckhoff]

The cam disc function makes synchronisation easy: regardless of the speed the system is running at, the AM8000 servo motors align themselves solely to the curve they are given. Some 100 self-built systems are currently in use in the capsule factory in Pinggau – including 14 that “simply” paint. One of these machines was recently extended by an additional part. “Because the lateral surface areas of our twist caps require up to three coats, depending on the colour, we decided to integrate a third machine into this production process in order to increase throughput rates,” says Reifbäck, explaining why they decided to give this running system a helping hand. Another optimisation measure, in particular, also helped to increase the performance significantly: it was decided to use servo drive technology from Beckhoff to transport blanks, rather than a pneumatic solution that had been used until then. “The project involved three individual systems that operate independently but have to run synchronously – because they form a unit together with the drying kiln through which every blank to be painted is fed,” says Bernhard Fischer, a member of the sales team at Beckhoff, describing the task they faced at BT-Watzke. The transport chain acts as the time base for this application, determining the nominal speed for all manipulations that have to be carried out in the individual machine parts. “We use an EL5151 incremental encoder interface for this purpose, which records the position of the transport chain as a virtual master axis. All subsequent motion sequences are aligned automatically using the cam disc functionsavailable inour TwinCATautomationsoftware,” says Fischer, pointing out a simple synchronisation feature that the maintenance department at the factory soon came to appreciate. The behaviour of the drives at maximum output of up to 200 cycles per minute can now be tested at slow speed after every reprogramming. “Regardless of the speed the system is running at, the AM8000 servo motors focus solely on the curve set for them,” says Wolf, commenting on the perfectly controlled synchronisation between the newly added machine part

[Picture: © Beckhoff]

Servo motors from the AM8000 series are used for attachment and detachment of capsule blanks at the revolver that is synchronised with production cycles. They also manage the movements of the turntable. and the existing units of the lateral surface painting system. Having to perform reference runs each morning is no longer required. “That was another aspect Beckhoff took into consideration in designing the drive technology. We wanted to be able to start immediately in the morning,” says the electrical engineer, outlining one of a number of small additional requirements BT-Watzke specified in this project. Up to 200 cycles per minute “We communicated what we wanted and indicated that in general a solution for up to 200 cycles per minute would be needed. We relied to a large extent on the experts at Beckhoff, however, when it came to the finer points of the implementation. They know best what their products can do,” says Wolf. Collaboration started as early as the concept phase and enabled an open exchange of ideas and views throughout the project. Workshop Manager Reifbäck first used his CAD program to design how the additional third machine part needed might look. He then had these proposals assessed and double-checked by Beckhoff employees. Some refinements and deliberations took place alongside this process. “I remember when Beckhoff’s drive specialist, Leo Büchinger, and I sat together in front of the screen.

Electricity + Control SEPTEMBER 2021

11