KUKA Creates System to Remove Securing Bands from Empty Bottle Crates

Problem:

Securing bands which hold crates of empty bottles together during transport back to the filling plant must be cut and removed before the bottles can be washed and refilled. The extent to which this process can be rationalized is shown by a robot functioning as an “escape artist” which locates the band, identifies its characteristics, cuts it and disposes of it. The benefit for the user lies in the high cost-effectiveness of the design: not only does it pay for itself quickly, it also provides production equipment with effective protection against band remnants.

Solution:

The company that created this solution, RST Roboter-System-Technik GmbH, was founded in late 1996 by Georg Gau in Barbing near Regensburg, Germany. Starting with just one electronics engineer as the sole employee, and one robot on loan from KUKA Roboter GmbH, based in Augsburg, RST soon developed its first palletizer for cardboard boxes. Since the start-up company had the benefit of Georg Gau’s wealth of experience in packaging line automation, its natural point of focus was packaging and palletizing. At present, RST’s customers are still primarily from the beverage industry, but interest from other branches is already growing.

With regard to the removal of securing bands, large breweries and producers of mineral water have already expressed serious interest. “One day someone from a brewery called to inquire about such a system”, relates Georg Gau. “Thanks to my connections in the beverage industry, I was soon able to find out whether or not there was a large overall demand in this area. What became clear was that almost all of the companies concerned had invested in band removal machines, but that they often switched them off and went back to removing the bands by hand. Otherwise, pieces of the securing bands would constantly be getting into vulnerable areas of the conveyor system and into downstream systems and damaging them”.

Georg Gau recognized this market niche, and in response designed a robotic cell for removing the securing bands from crates of empty bottles. This features a KUKA KR 15 robot, mounted in inverted position over a roller conveyor; the inverted position of the robot saves floor space. The robot gets its start signal when a carrier stops beneath it. The KR 15 uses an integrated camera to find the loaded pallet, gages it with respect to its height and edges, and quickly and reliably locates the securing band. Because the cell is easily protected against interference from external light, the availability of the camera system is similar to that of the robot, which approaches 100 %.

After identifying the strapping material, the KR 15 inserts its tool between two of the beverage crates and cuts the securing band at one side of the stack. It makes no difference here whether cords, plastic bands, adhesive strips, or steel bands are involved. The cutter used for this purpose is equipped with hardened blades, and is able to cut steel bands up to 3 mm thick. This process does not place any mechanical stress on the empty bottles, and no centering is necessary.

On the other side of the stack, a fixture holds the strapping in place against the crates with a gentle, foam-buffered pressure until the robot grips it, and - after cutting it again - disposes of it in a container. Cords and bands which get stuck are trimmed as short as possible by the robot. This way it prevents longer pieces from getting wrapped around parts of the system during later operations downstream. The robot separates stacks of crates held together by adhesive strips by simply cutting the strip between two of the individual crates. With this robotic cell, it is no longer necessary to vacuum up the straps, a procedure that tends to be problematic; furthermore, the changeover work previously required for varying beverage crates and pallets is no longer needed.

The high acceleration capacity of the KR 15 guarantees that all necessary points on the path will be reached quickly. Of the 30 seconds available for the cycle time, 10 seconds are allowed for moving the pallet into and out of the cell. Since the robot does not use all of the remaining 20 seconds, a reserve capacity exists for use on unusual securing bands. The time required for such bands could, in some instances, cause a pallet backup, but this is compensated for by means of a buffer segment in the line.

The end-effector attached to the KR 15’s wrist combines very different functions like recognition and cutting, and at the same time leaves space open for installation of additional tools or vision systems. The advantage for the user could hardly be more obvious: this kind of robotic cell can be re-equipped at any time, and can thus be adapted to suit changed work conditions or processes.

So that the robot can by itself recognize the material to be removed, programs for a large variety of beverage crates and securing bands are stored in the KR 15’s controller. Programming is carried out by means of the KUKA Control Panel, with its Windows-based user-friendly man-machine interface.

 “We developed this new process to the point where it was ready for the market in very little time; from the idea phase to presentation at the Brau 98 trade fair in Nuremberg took just under three months”, says Georg Gau in summary. “We promise our customers that it will pay for itself quickly; with two shifts that will take about one and a half years. Since the intelligent robotic cell can be converted flexibly in response to new requirements, every user is also guaranteed to be making an investment in the future.”

This design is a prime example of the systems partner strategy, in which KUKA Roboter focuses systematically on core competencies. The company from Augsburg combines its own robot-specific expertise with the respective industry-specific knowledge of its partner, in this case RST Roboter-System-Technik, thus achieving significant synergy effects. This way every user gets a solution that incorporates key robotic technologies – and also a turnkey system.

Author: Jürgen Warmbold, freelance technical journalist, 27327 Martfeld