Flexible e-chains and cables for grippers in BD Rowa picking systems

Profile

• What was needed: Series E2 and 2500 energy chains, chainflex cables, including CF10 power and control cables, CF11 data cables and CF99 control cables.

• Requirements: Cable solution for multi-dimensional movements of the energy and signal supply with special requirement profile, S-shaped movements, bend radii of more than 180°, long service life with minimum noise development.
• Industry: Mechanical engineering, chemist's warehouse
• Success for the customer: Individually created solution for cables and cable guidance, tests in the igus laboratory, particularly flexurally resistant cables without core ruptures and with minimal wear, particularly compact type

The automated storage and order picking has been implemented – thanks to Rowa – in the chemist's shops. The latest generation Rowa Vmax system.

Problem

In 1996, the newly founded Rowa Automatisierungssysteme GmbH launched the first fully automated storage and order picking system for chemist's shops. In the meantime, Rowa has installed more than 5,000 of these systems; and with around 3,000 installed systems in Germany, Rowa has even secured a market share of around 70 percent. From the chemist's point of view, automation saves a lot of space and even more time. It also creates the right conditions for a reduction in inventory levels and thus capital commitment.
The gripper system is the heart of the machines. The latest generation of the patented HD-Multi-Picking gripper can simultaneously move up to eight packages - of the same variety or even different ones.  In the narrow aisle of the storage system, two gripper systems can work in parallel and without collision, which doubles the picking performance and allows the grippers to make very complex coordinated movements to store and retrieve the desired goods as quickly as possible.
However, the high freedom of movement also includes high requirements for the energy and signal supply as well as the cables. These have to follow the multi-dimensional movements without any problems, which places significantly greater demands on the energy chains and cables than in most other automation applications. For example, the cable guidance must allow S-shaped movements with very tight bend radii and be able to stretch in the opposite direction.
Despite the heavy loads, a long service life was a particular core concern for the customer. And a no less important development goal was to keep noise emissions as low as possible. The increased service life was not to be at the expense of noise generation.

Solution

Today, Rowa uses the igus product range for energy and signal supply systems as well as cables.
Even though the chainflex cables were explicitly developed for very high stresses and intensive movements, the systems represented a special requirement profile.  The frequent bending beyond a bending angle of 180 degrees and the simultaneous use of a very small radius puts a lot of stress on the cables. In order to find the optimum solution, Rowa provided the igus team with two gripper systems.  Endurance tests were run in the igus laboratory and the electrical specifications of the cables were tested - with the result that in some cases different core cross sections were chosen. The focus was clearly placed on the service life so that the systems can run maintenance-free.
Specifically, chainflex cables of the CF10 type are used as energy and control cables as well as cables from the CF11 series as data cables. In all series, according to the tests, the conductors have an extremely bending-resistant design and construction, the special stranding ensures a lasting flexibility in multiple dimensions without core ruptures and with minimum wear. In some applications, where the cables have extremely small radii, a control cable of the CF99 series with an alloy conductor is used, because even smaller radii are now possible.
For the energy chain, which is subjected to the same stresses as the cables, the radius of the chain had to be individually adapted due to the installation space. Here, the igus designers have done detailed work to achieve maximum availability.  The E2 series energy chains are used here in enclosed and open design on the gripper and the 2500 series for the longitudinal travel of the complete gripper system along the racks.

The grippers are characterised by special mobility and can grip up to eight packages at once.

Chain and cables accomplish maximum performance in the Rowa grippers. Here a drylin lead screw module from igus is also used.

The igus energy chains and cables are also used in the fully automated Rowa ProLog storage systems, which automatically identify the medicines and specify a storage location.

The chainflex cables have been developed from the ground up for mobile applications. Therefore, the special stranding is part of their design features.