Leading material handling integrator, TGW, has recently implemented a new automated logistics system within Aesculap, a global supplier of medical equipment, in order to handle their growing volumes and meet the high service levels that the surgical practice demands.
Faced with the challenge of improving their existing intra-logistics operations, TGW worked closely with Aesculap to deliver a cost-efficient logistics solution that not only meets the current requirements of the business, but which also allows for future expansion and increase in capacities.
The products and services used in surgical procedures are the core competence of Aesculap, a division of B.BRAUN Melsungen AG. The product range of the company includes surgical instruments for open or minimal invasive surgery, implants for orthopedics, neurosurgery or spinal surgery, surgical sutures, sterile containers, devices and navigation systems as well as products for the cardiology sector.
Limited Capacities
The former logistics centre of Aesculap in Tuttlingen, Germany, had grown considerably since its opening in 1989, and had experienced significant changes and extensions to its in-house material handling and storage operations. With throughput capacities reaching the logistics centre's limits in 2006 and its 5-year corporate strategy projecting substantial growth, an improvement to the current system was necessary. Consequently, a logistics solution was designed that permitted the further utilisation of the existing premises as well as the construction of a new building on the company site.
"The new solution has to be capable of handling 2,500 consignments per day", explains Bernd Hermle, Logistics Director at Aesculap. "The order sizes vary considerably. The smallest orders consist of only one item, whereas large orders may include new equipment for an entire hospital unit with a correspondingly high number of order lines."
To achieve such diversity in order volumes, a sustainable picking system had to be designed to perform 13,000 picks during a ten-hour day operation.
'Flashing Light Drives' Determine Order Lead Times
The logistics solution had to guarantee very high service levels and ensure that high-priority orders are fulfilled in the shortest possible time. "It is crucial for our customers that all orders with priority 1 requested up to 4:45pm are shipped by 5:30pm on the very same day", says Bernd Hermle. An even shorter lead time is required for the so-called 'flashing light drives', which are those orders containing urgently needed surgical items to be collected directly by emergency vehicles.
Strict batch tracing is required by law for all medical products which applies to Aesculap's goods. Furthermore, the special conditions of such goods require extremely gentle handling. "Our products are very delicate and often require sterile packaging", explains Bernd Hermle. "Therefore, it is essential that all sharp and pointed surgical instruments are not damaged in any way during handling."
The material handling system designed by TGW not only delivers this required level of care in handling, but also delivers the guaranteed high picking performance through a time and route optimised 'goods-to-man' picking solution where accuracy is assured by means of 'put-to-light' technology.
A Solution Connecting Goods-In, ASRS and Order Picking
The design of the high performance picking solution took into account all areas of the logistics centre, starting at the goods receiving area. Each goods-in workstation carries a stock of three different tote heights all of which are handled in the mini-load automated storage and retrieval system (ASRS). These totes may be sub-divided with up to eight sections. If one of the sections becomes empty at a picking station, this tote is directly diverted to the goods-in area and filled with corresponding goods. After replenishment, the tote is sent back into the warehouse or transported to the picking workstation if there is a pick demand for any of the contents.
The automatic mini-load storage and retrieval system or ASRS, allows for a performance of 1,365 double cycles per hour and accommodates over 51,240 totes. Three storage aisles, with a total of 38,630 double-deep storage positions, are served by high-performance TGW Mustang stacker cranes. The three aisles provide direct access to all C classification items and are used as replenishment buffer for A and B categorised items.
TGW Booster: High Performance Order Picking Supply
Another six aisles of the automatic mini-load ASRS are equipped with TGW Booster stacker cranes. This type of storage and retrieval machine is 5m high, extremely lightweight, dynamic and cost-effective, making it the perfect device for very fast order picking transactions. These aisles are arranged in two blocks of three, installed one on top of the other and located between the three Mustang aisles. The two storage blocks accommodate all A and B classified items on 12,600 single depth storage locations offering 100% direct access of the stock for order picking.
"The order picking area was divided into three sub-areas" explains Bernd Hermle. "There are approximately 200 'classification A' items and these are picked at three workplaces that are automatically provided with order totes by the Warehouse Management System (WMS). Mobile data acquisition devices direct the operators to the corresponding shelving rack locations. Depending on the number of operators who are logged in, the WMS also controls the size of the picking area to be covered by each of the operators, optimising the entire picking process".
Ergonomic Workplaces for High Picking Performance
The 20,500 A, B and C classified items, which account for approximately 70 % of the entire picking activity, are picked at eight highly ergonomic workstations. Each picking workstation consists of two in-feed conveyor lines for totes coming from the mini-load ASRS, one out-feed conveyor line for totes going back into the ASRS, one inclined out-feed conveyor line for order totes, two buffer lines at face level for the provision of empty order totes and eight pick-to-light positions.
"The design of the conveyor system permits future extensions without having to interrupt the operation" adds Bernd Hermle. "Furthermore, the workstations can be extended by three more positions with minimum impact on the operation".
The remaining 10% of the picking performance is represented by about 700 items picked from the high bay warehouse using narrow-aisle forklift trucks in a two-stage procedure. Firstly, multiple orders are collated onto pallets as a batch pick; and afterwards the goods are distributed to their respective order totes.
Order Consolidation in High Performance Mini-Load Aisle
A special feature of the intra-logistics solution is the order consolidation area, where all orders that are distributed over several totes, due to their size, or include goods from different picking areas, are prepared for consolidation ready for despatch. All the order totes are automatically collated into one dedicated mini-load aisle, serviced by a TGW Booster stacker crane. Once all the totes for an order are available in this high-performance buffer, they are automatically retrieved and presented to the operators on a conveyor spur. The operators withdraw the totes from the spur and prepare the goods for despatch.
Small orders are directly transported from picking to a small order despatch area. This area consists of 12 workstations in which the goods are packed for shipping.
Seamless Interface Between SAP and CI_LOG
Inventory management, storage and retrieval functions, merchandise management, stocktaking and material flow control are all mapped in the supply chain software CI_LOG by TGW. The software interfaces with the ERP system SAP, and all transactions are communicated between the two systems.
SAP manages the overall warehouse stock in the Warehouse Management (WM) module, making no differentiation between the distinctive storage areas of the installation, i.e. all storage areas such as mini-load, manual pallet storage and manual fast-moving items storage are mapped as 'Blackbox'. CI_LOG is the WMS designed by TGW that manages all stock control tasks such as inventory and load carrier management in all storage areas, master data and stock management of all loading units as well as all workstation-related functions (goods-in, order picking and order consolidation).
TGW Solution Saves Cost
The new intra-logistics solution provided considerable advantages to Aesculap in comparison to the former logistics operation. Bernd Hermle explains, "The ergonomic and clearly structured operational processes at the mini-load picking workstations have helped us to minimise error rates and achieve a higher performance. The solution for the A, B and C classified items led to substantial cost savings, minimised throughput times and reduced space requirements. Furthermore, the increase in capacity and productivity has laid the foundations for further growth."