Hans Kohler AG, Switzerland’s largest stainless steel dealer, has invested 4.5 million CHF in the new fitting warehouse at the location in Dietikon. Using automated processes, the company can operate significantly more efficiently and effectively today. Simultaneously this also provides a solid basis, which will also ensure stability in the future.
High bay warehouses, harmoniously integrated into the landscape from a visual point of view, are still quite rare. Hans Kohlers’s new fitting warehouse in Dietikon is worth seeing. But the integrated logistic features are also interesting. After its successful go-live in August 2012, this medium-sized commercial stainless steel enterprise with headquarters in Zurich, can now handle its orders significantly faster and more efficiently. The prerequisite for this was automation of the entire facility, which promised significantly higher availability as well as improved labor safety.
Highest possible capacity and performance in limited space
The new fitting warehouse is a part of a comprehensive reorganization project. Hans Kohler AG started the initial planning for GIZELA (Giessen Central Storage) in 2008. Benno Kündig, Logistics Project Manager, summarized the original situation as follows: “In Schlieren and Dietikon we operate three storage locations, none of which satisfy today’s requirements. The storage capacity was limited and not in line with future growth.” Nor were the logistics systems up to the state-of-the-art. However implementation of a higher degree of automation was not practical in the existing space.
The challenge was therefore to erect new facilities on the relatively narrow lot, to completely use the property and thus provide optimum prerequisites for storing, picking and handling approx. 7,500 products, subdivided into approx. 25,000 various batches. This resulted in construction of new building with a volume of 8,000 m³ with integrated, automatic high bay warehouse (HRL) for pallets with three height classes as well as an automatic small parts warehouse (AKL). In the first phase, the ground floor is equipped with a 1,200 m² picking area with four work stations.
The equivalent area on the second floor, which can be used as required at a later time, was prepared for later connection of the conveying equipment. “Custom dimensioning of the building and installed equipment allowed us to used the existing area completely and optimally”, explained Kündig. Provisions for expansion were considered by annexing the small parts warehouse (AKL) at the side to permit expansion to the east.
The entire ‘panoply’ from one company.
The end of June 2011 Stöcklin Logistik AG received the contract to realized a suitable storage concept for the fitting warehouse. However the concept and execution specifications did not focus entirely on the high bay warehouse (HRL) and small parts warehouse (AKL). Hans Kohler AG also entrusted a great deal more to the Swiss intralogistics specialists: A container bay system, storage bays for small parts warehouse (AKL), PLC controls (programmable logic control - SPS) including material flow computer with system visualization as well as fire doors.
Moreover the commercial enterprise ordered a fleet of various floor handling equipment “made by Stöcklin” from the general contractor and system integrator, for highly varying handling and transport tasks. “Stöcklin is well known for quality and process knowhow”, stated Hans Kohler, Business Manager and Governing Board Delegate. Another decisive factor for granting the contract was also the service life assessment, guaranteed by Stöcklin for a period of 10 years. Stöcklin Project Manager Thierry Briswalter added: “Another factor is certainly the local proximity. Long transport routes between production and points of use are eliminated.”
Increase in both performance and availability
Over a length of 62 m, the automatic high bay warehouse (HRL) is laid out for a capacity of 6,200 pallet storage locations with single depth storage. Three stacker cranes (RBG) from Stöcklin’s MASTer series run in the three aisles, moving pallets with a maximum cargo weight of 1,350 kg. The single mast units equipped with telescopic forks are designed analog to the various heights specified for all three aisles of 12.5 m, 17.0 m and 21.5 m. Euro-pallets as well as chemical pallets with deviating dimensions of 1,200 x 1,200 mm are handled. The MASTer 24 stacker cranes (RBG) are laid out for operating speeds of up to 2.0 m/s with an acceleration rate of 0.45 m/s2 and achieve raising and lowering speeds of 0.50 m/s. The possible throughput rate is calculated to be 900 pallet movements per day.
After delivery to stock receiving, the pallets are transferred to the conveying equipment and centered automatically by the elevating transfer unit. Simultaneously the type of pallet is identified by a light barrier. The pallet identity is logged with the support of a laser scanner mounted on one side. An effective weight scale is also located here to allow the warehouse management system to check the plausibility. After booking in, the pallets are routed to the transfer stations for storage in the high bay warehouse (HRL). As previously at the inbound location, Euro-pallets are also moved back 200 mm at these transfer stations, to allow the pallets in the high bay warehouse (HRL) to always be picked up from the same position.
The pallet conveying equipment upstream of the high bay warehouse (HRL) consists of two double picking stations and one each storage/retrieval conveying path. Pallets requested for picking are taken over by a distributor carriage and moved to the work stations in question, which are also equipped with an effective weight scale for checking the plausibility of the picking quantities. The travelling speed of the distributor carriage is 1.0 m/s with acceleration values of 0.5 m/s2. “Although higher speeds are possible, they are not practical due to the short distances travelled at this point, because the speed cannot be reached during operation,” stated Briswalter. The pallets are logged by hand scanners at the picking as well as transfer and outbound locations in shipping. These stations are always approached by the distributor carriages so that the gripping depth is optimal for the worker, i.e. on the roller conveyor the edge of the pallet - regardless of whether Euro or chemical pallet - is always positioned toward the picker. The four safety light barriers, so-called muting systems, between the picking stations and distributor carriage ensure that no one is injured even when work gets “distracting”.
The small parts storage warehouse (AKL) is served by five 12.5 m high stacker cranes (RBG) from the light-weight BOXer series. Five aisles with a length of 35 m each and clear width of 784 mm provide 22,000 container storage bays for single depth small parts storage. The load handling device is designed as a telescopic unit with stationary belt conveyor. The BOXer E1 stacker crane (RBG) ensures that nearly 2,800 containers can be transferred to the picking stations daily. A total of approx. 6,000 containers can be moved each day. This requires travelling speeds of 4.0 m/s and acceleration and deceleration rates of 1.7 m/s2. A lifting and lowering speed of 1.5 m/s is also guaranteed.
The picking work stations were connected using container conveying equipment. The entire system consists of seven multiple container tracks with integrated receiving, transfer, retrieval and packing stations. In order to comply with the required noise emission limits Stöcklin Logistics abstained from using compressed air here. For this reason all drives operate electro-mechanically. By contrast empty containers are fed in using dynamic pressure systems. Electro-mechanical belt elevating transfer units are used wherever it is necessary to transfer storage containers with weights up to 50 kg.
During the course of picking, the quantity to be removed from the containers provided is shown via “pick-to-light”. An automatic laser scanner is installed at each filling station for identification of the attached bar code to ensure an error-free “pick-to-light” function at the picking containers. This also guarantees that the empty containers to be filled at the stock receiving stations as well as at the high bay warehouse (HRL) transfer station are set down in the proper direction. The warehouse management system (LVS) displays how to subdivide or fill these containers only after successful conclusion of this identification process. The “marriage” of a new empty container with an order is then started with hand scanners to initiate a new order. In the course of pushing back the empty order containers from shipping, the load carrier is fed in visually, i.e. as soon as the outbound zone is free, it can be pushed in. Containers to be categorized as “NOK” (not okay) due to a bar code or height error, are discharged via an NOK path and then fed back to the picking station after remedying the problem.
The order goods are transferred to the shipping lines under the control of the warehouse management system (LVS). The first container in a line is scanned by the operator for certain identification. Removal of the goods is confirmed on the display module and the container can be removed. The empty containers from shipping are placed on a storage worm and transported in the direction of the empty container buffer.
Equipped for all contingencies
All orders and logistics processes including batch management, internal transport operations and loading inspection are controlled by the warehouse management system (LVS). In addition to regular functions, the connected material flow computer (MFR) is enriched with an energy management system for the stacker cranes (RBG) moving in the high bay warehouse (HRL) and small parts warehouse (AKL). This feature transfers excess braking energy to the other travel axes via an intermediate coupling. The stacker cranes (RBG) start up at offset intervals and the travel dynamics are organized depending on the order. The energy consumption of the stacker cranes (RBG) as well as the number of trips are also measured and analyzed continuously to improve the work distribution according to electricity rates. The material flow computer (MFR) also includes 2D system visualization, with which the current behavior of the entire system can be called up at any time on the control panel in real time. Any malfunctions are localized immediately and relayed to the control panel, so that the operator can intervene as quickly as possible and restore smooth operation. The subject of visualization was, however, placed on the agenda at an early time. “Simulation of the overall system with real orders at peak times made it possible to precisely verify the dimensioning and layout on a preliminary basis”, stated Thierry Briswalter. Benno Kündig was satisfied with the solution finally implemented: “We were successful, in achieving maximum performance with a comparatively small area and simultaneously increase the storage capacity including reserves.” These were the primary objectives the the GIZELA project initiated at the Hans Kohler Company. The fitting warehouse in Dietikon now already equips up to 1,200 items daily and ships approx. 50,000 packages a year to customers.