Innovative blade assembly robot for slitting line
The team around Plettenberg-based production and project manager Martin Krämer is justifiably proud of the new blade assembly robot. Its main job is to assemble the tools for the blade shafts1 on one of the slitting lines in the production site. To do this, the robot has to select the right combination from a stock of 3,000 tools. The clever thing about this is that the robot’s systematic selection of blades, ejector rings, and adjusting rings is based on algorithms incorporated into the control software containing the knowledge of Waelzholz’s specialists regarding the combination of blade condition, quality, and tensile strength of the material being cut. But that’s not all. Martin Krämer explains further special features: “The new robot can not only automatically remove certain tools from one of the three rotating storage towers and assemble a slitting setup from them. The line also includes a control station that monitors the condition of the blades’ cutting edges. Before this takes place, the blades are cleaned of dirt in an inline washer – and all of this happens while the robot is in operation.” The robot’s extremely precise functionality is also quite impressive, as Martin Krämer explains: “The robot can securely grip tools from a width of only 1 mm (0.039 inch). This requires an extremely high degree of precision.”
Waelzholz expertise in the control software
A nine-member project team at Waelzholz spent many months meticulously programming and setting up the robot. During the team’s collaboration with the supplier, it was possible to extensively customize the system technology and software functionality. This enabled a large share of the Waelzholz team’s expertise to be incorporated into the system. Dennis Fischer, project member and responsible for the production lines’ electrical systems at the Plettenberg site, explains an example of the functionalities they developed: “Together with the equipment supplier, we optimized the blade inspection station to identify the blade condition in the increments we require with absolute precision. The blades are monitored after each pass. If a blade is no longer sharp enough or exhibits signs of chipping, the system removes it from the line and it is sharpened in our in-house grinding shop for reuse later.” When inspecting the blade edges, Waelzholz has set an extremely high standard of precision. “The cut needs to be optimal, particularly where materials with functional edges are concerned. This means the blades need to be in perfect condition,” says Fischer.
Furthermore, it is precisely this development work that has made it possible to combine exact tool specifications for the material being cut with a defined assessment of the respective blade conditions. Gregor Winkler, project member and group leader in production at the Plettenberg site, explains the benefits: “Not only does this ensure that we use the optimal blade for each application, but the defined and standardized setup of the tools also enables us to ensure a repeatable slitting result across many delivery batches, regardless of who is operating the line.”
Teamwork across departments
In addition to the custom-developed robot technology, the internal team’s smooth collaboration is also worth mentioning. Krämer reports: “We had to coordinate across multiple departments – including electrical and mechanical engineering, production, and purchasing – throughout the entire blade assembly robot project. I would like to thank everyone involved for their hard work and dedication – from early in the morning until late at night, on weekends, and even on holidays – and for their fantastic teamwork.”
New robot technology increases efficiency and relieves strain on employees
“Our requirement for the manufacturer was that the robot should fully automate the entire tool assembly process, including the transfer and retrieval of the slitting setup to and from the rotary table. This includes both the aforementioned edge inspection and the washing of the tools,” sums up Timo Ludwig, who is also a member of the robot project team and is responsible for the mechanical systems at the Plettenberg site. This complete process will increase the efficiency of the slitting line in the future. What employees used to do by hand with the same level of precision is now done by the robot, sometimes faster and with unwavering accuracy. The employees operating the slitting line can now use the time saved productively to achieve a higher tonnage.
The employees also appreciate the ergonomic benefits that the robot offers them, as they no longer have to move the heavy tools by hand, as Ludwig explains: “If tools have to be changed several times during a shift, the weight that has to be moved can add up to more than a metric ton (2,205 lbs) over the course of a day.”
All in all, the new slitting robot represents another important step for Waelzholz in the automation and optimization of its own production processes. But for the technology leader, robots in the cold rolling industry are nothing new – the company already uses robot applications at several of its international locations to increase quality and flexibility.
1 Blade shaft: cylindrical axle that is equipped with tools (blades, rubber ejectors, spacer rings) in a defined sequence for the respective slitting process. The slitter head consists of two blade shafts, one above the other: a top and a bottom shaft. The material being cut passes between the two rotating blade shafts and is cleanly and precisely cut to the desired final width according to customer specifications.
Construction of the blade assembly robot at Waelzholz
01 Slitting line
02 Safety enclosure
03 Rotating tool storage towers
04 Blade edge inspection station
05 Washer
06 Robot gripper head
07 Tool transfer point between robot and rotary table
08 Slitting setup
09 Rotary table
10 Guide rail
11 Slitter head in the slitting line
Process steps inside of the blade assembly robot
Path of a tool (e.g., a blade, shown here in blue) from the tool storage tower to the rotary table.