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

High service life of cable routing with 180° bend radius and multi-dimensional movements

Today, many pharmacies no longer retrieve medicines from drawers, but rely on an automated warehouse. Behind this is always an automated storage and picking system - and often one from CareFusion | Rowa. The Eifel-based company has been a pioneer in the field of pharmacy automation since 1996 and has established itself on the market. The chainflex® cable and energy chain from igus® ensure the reliable supply of energy and signals to the highly manoeuvrable grippers.

Profile

What was needed: E2 and 2500 series energy chain, chainflex® cable, including CF10 energy and control cable, CF11 data cable and CF99 control cable
Requirements: Cable solution for multidimensional movements of the energy and signal supply with a special requirement profile, S-shaped movements, bend radius of over 180°, high service life with minimal noise development
Industry: Mechanical engineering, pharmacy warehouse
Success for the customer: customised solution for cable and cable routing, tests in the igus® laboratory, particularly bend-resistant cable with no wire breaks and minimal wear, special compact type

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Vmax order picking system with chainflex

Problem

In 1996, the then newly founded Rowa Automatisierungssysteme GmbH presented the first fully automated storage and picking system for pharmacies. In the meantime, Rowa has installed more than 5,000 of these systems, and in Germany, with around 3,000 installed systems, Rowa has even secured a market share of around 70 per cent. From the pharmacist's point of view, automation saves a lot of space and even more time. It also creates the conditions for reducing stock levels and thus capital commitment.
The centrepiece of the systems is the gripper system. The latest generation of the patented HD multi-picking gripper can move up to eight packs - of the same type or different types - at the same time. 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 perform very complex coordinated movements in order to store and retrieve the required goods as quickly as possible.
However, the high freedom of movement also places high demands on the energy and signal supply as well as the cable. These must be able to follow the multidimensional movements without any problems, which means that the energy chain and cable are subject to significantly greater demands than in most other automation applications. For example, the cable routing must allow S-shaped movements with a very tight bend radius and be able to stretch in the opposite direction.
Despite the heavy load, a high service life was a key concern for the customer. And an equally important development goal was to minimise noise emissions. The increased service life could not be achieved at the expense of noise emissions.

Solution

Rowa now uses the igus® product range for energy and signal supply systems and cables.
Even though the chainflex® cables were explicitly developed for very high loads and intensive movements, the systems presented a special requirement profile. The frequent bending beyond a bending angle of 180 degrees and the simultaneous use of a very small radius put a lot of strain on the cable. In order to find the optimum solution, Rowa provided the igus® team with two gripper systems. Endurance tests were carried out in the igus® laboratory and the electrical specifications of the cable were tested - with the result that the decision was made in favour of partially different wire cross-sections. The focus was clearly placed on service life so that the systems can run maintenance-free.
Specifically, chainflex® cables of type CF10 are used as power and control cables and cables from the CF11 series as data cables. As a result of the tests, the conductors in all series are designed to be extremely resistant to bending, and the special stranding ensures permanent flexibility in several dimensions without wire breaks and with minimal wear. In some applications where the cables have extremely small radii, a CF99 series control cable with an alloy conductor is used to enable even smaller radii.
In the case of the energy chain, which is subjected to the same stresses as the cable, the radius of the chain had to be customised due to the installation space. Here, the igus® designers worked on the details to achieve maximum availability. The energy chain-series E2 is used here in closed and open design on the gripper and the 2500 series for the longitudinal travel of the complete gripper system along the racks.

Overview energy chain E2

chainflex® cables

"We prefer to use high-quality standard components - not only for cost reasons, but also because of availability. We have concluded service contracts for most of the systems and are therefore responsible for ensuring that there is no downtime."

Stephan Brokonier, Electrical Design Team Leader at CareFusion | Rowa

Further cooperation between Rowa and igus®

This development co-operation was not the first for igus® and CareFusion | Rowa. Andreas Pauli: "We have been working with igus® for many years and appreciate both the accuracy with which our concerns and enquiries are processed and the flexibility and speed with which tests are carried out, for example." That is why we are currently working on further development projects. One concerns a new series of sorters that separates and identifies the medicine packs to be stored and assigns them a storage location. Moving cameras are used for this - and igus® has the relevant expertise for data cables in image processing applications. In terms of bus technology, CareFusion | Rowa is planning the next steps and can obtain the corresponding flexible cables from igus®, for example for Ethernet and other data standards. A major advantage here is that the variety of qualities of the bus cables means that you can choose exactly the right one to get exactly the cable you need.
Another current topic for CareFusion | Rowa is the qualification of the systems in accordance with the North American UL/CSA standards. Being part of CareFusion opens up additional opportunities for Rowa systems in the American market, which follows different "rules of the game" when it comes to the approval of cable types. Andreas Muckes: "The European standards focus on the materials and wall thicknesses used, while the UL/CSA take a different approach and concentrate on the flammability of the components. This requires new tests and documentation tailored to this." The igus® components used require little additional work for this task: they are already available as a UL/CSA-certified solution.