Fast and flexible production of bent wire components
Technical brushes are part of our daily lives. We encounter them all the time, often without even noticing. Specialty types include strip brushes, twist knot brushes, dental brushes, street sweeper brushes and chimney brushes, as well as paint rollers. Wöhler Bohemia, the leading manufacturer of specialized machines for the production of technical brushes, has recently outfitted its machines with cutting-edge automation solutions from B&R.
Wöhler Bohemia was founded in 1994 as a subsidiary of the German companies Wöhler Messgeräte Kehrgeräte GmbH and Wöhler Brush Tech GmbH. Together they now form Wöhler Holding GmbH. The company sells industrial technical brushes, chimney cleaning equipment and specialized machines for brush production. Under the category of twist-in brushes, Wöhler produces heat-resistant brushes with silicon carbide and diamond additives. They develop and build production machines for paint rollers, primarily frame parts, as well as offering chimney cleaning equipment and chimney sweep accessories.
Since 2006, Wöhler Bohemia has been working together closely with B&R to develop a range of control solutions, drives and control cabinets, with additional intensive cooperation on programming, troubleshooting and training. The consistently exceptional quality of B&R's products and services provides an optimal foundation for the expansion of Wöhler's business in the area of specialized machines.
The first step in the production of paint roller frames is to remove the wire from the servo-controlled coil holder. The wire is fed through a straightening unit before being received and measured on two pairs of servo-controlled rollers. The next step is to press stubs onto the wire to prevent it from twisting inside the plastic handle. Another pair of stubs can be pressed onto the other end to keep the roller from slipping on the wire. The number of pressing units can be varied to accommodate the design.
Once the sleeves have been pressed on the wire, it is bent into the desired shape. The bending process is normally performed in three bending and moving steps. The bending unit is also servo-driven. Finally, the frame is assembled from the bent wire and the handle, which is supplied from a magazine through a vibrating conveyor.
Wöhler Bohemia's proven paint roller frame production machines – the ADMV and ADMV SM – are now complemented by a completely revamped new generation: the ADMV 3S, presented at the Interbrush 2012 fair in Freiburg. The new ADMV 3S can handle two different wire diameters, which it uncoils, measures, presses, bends, deburrs and assembles with a plastic handle – all within 1.4 seconds. That makes 40 frames per minute, or twice the capacity of the machine's predecessors.
Three servo drives govern the bending cams and allow all three steps of the previous bend-move-bend-move-bend scenario to be performed virtually simultaneously.
An older B&R control system and PP21 panels were replaced by the B&R X20 I/O System, which communicates with the PP420 controller via POWERLINK. The ACOPOS inverters controlling the machine's axes are also connected via the POWERLINK bus. "Upgrading the control system and the bending unit not only allowed us to increase the capacity to 2,400 frames per hour," says Jaroslav Markvart, general manager of Wöhler Bohemia, "it has also simplified wiring and made work easier and more comfortable for the operator."
Equipped with a touch screen and running software developed in Automation Studio, the controller allows the size and shape of the frames to be programmed exactly as needed. The system also helps manage performance, downtime and fault monitoring.
High-tech production machines with B&R technology
"B&R has helped us branch out to new customers outside the brush industry. Our variety of wire bending units with pressing and assembly tools can be used in a wide range of applications. We are also moving towards 3D bending capabilities," concludes Markvart.
The ADMV 3S from Wöhler Bohemia, a machine for producing paint roller frames, relies on POWERLINK. This real-time capable Ethernet protocol allows the X20 I/O system to communicate with the PP420 controller and integrates the ACOPOS inverters that drive the machine's axes. The machine produces 40 frames every minute – double the capacity of its predecessor.