The paper was presented at the International Logistics Conference “Logistics 2002 – Flexible supply chains – concepts, experiences, challenges”. Poznań, May 14-15, 2002.
Introduction
As part of a joint project between Rolls-Royce Deutschland Ltd & Co KG, Projektlogistik GmbH, and Technische Fachhochschule Wildau, a logistical analysis of physical and information flows was conducted to develop proposals for the future technological layout of the assembly hall. The task of the project was to identify potential sources of reserves in the turbine assembly process, thereby creating premises for the decision-making process aimed at ensuring a 40-day delivery cycle.
The 40-day delivery cycle is defined as a goal for the operational units of Rolls-Royce Deutschland Ltd & Co KG, consisting of reducing order lead times to 40 calendar days. Flow time serves as an efficiency indicator for the order fulfillment process, implying goals for quality, costs, inventory, and meeting delivery deadlines. The flow time indicator is the time calculated from the launch of an order, which in the case of internal and external suppliers is 30 calendar days before the start of turbine assembly, and achieving a 10-day assembly time at the production plant in Dahlewitz. Rolls-Royce Deutschland Ltd & Co KG defined assembly time as the period between the first booking of material in an assembly order and the transfer of the turbine to the finished goods warehouse and subsequent shipment to the customer. By commissioning the implementation of this project to Projektlogistik GmbH, which carried it out together with students from Technische Fachhochschule Wildau, Rolls-Royce Deutschland Ltd & Co KG chose a logistics consulting firm from the client’s area that cooperates closely with a technical university. Thanks to this, logistics processes were also analyzed, thus obtaining an elementary structure of logistics processes.
Material flow analysis
The first milestone was the analysis of material flow and its graphical representation. Due to the high variety of parts, parts of groups A and B for both turbine types, BR 710 and BR 715, were prepared in the form of a bill of materials. The analysis was performed by 4 teams. Based on the analysis of assembly process sheets, observations, and interviews with assembly workers, the physical flow of parts or modules was recorded. The number of parts, the route, and the times (requested time and examined time) of the flow of parts were presented in the form of segments of the technical layout of the assembly hall or individual modules. The evaluation of the results already showed savings potential in the sphere of flow, thanks to the possible reorganization of workstations or measuring devices within individual assembly zones.
Fig. 1. Illustration of material flow.
For optimal material flow, information flow is of central importance. Based on the observations and interviews with employees, another source of flow improvement was identified in this area as well.
Fig. 2. Information flow.
The first was relieving the assembler of non-value-added activities, such as material transport. More attention was also paid to communication between assemblers of individual modules during the assembly process. The assembler is the most important link in the assembly process and for this reason, they must have access to the information necessary for performing their assigned tasks. This applies primarily to assembly process sheets regarding the processes they perform, but also to information/requirements related to preceding and subsequent processes. Calculations made on the basis of plant data records showed a very varied output over a period of 17 calendar weeks (from 3 to 7 turbines per week), with a weekly material stock for an average of 28 turbines. This is obviously associated with high capital commitment, which, however, can be minimized as a result of shortening the flow time.
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