Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology / Logistic Engineering
B.J. Goossens Materiaalbeheer KLM Catering Service.
Masters thesis, Report 93.3.LT.4090, Transport Technology, Logistic Engineering.
KLM-Catering makes arrangements with caterers all over the world to supply KLM flights with everything needed for the catering aboard. To do this these caterers need KLM equipment, like trolleys, containers, plates and cutlery. The objective of this research is to determine how to control this equipment flow with minimum costs. The organisation of the material management was also an issue in this research. Two other questions were "How do we determine the rotability (number of flights equipment can be used) of our equipment?" and "What is the pipeline with the introduction of new equipment?".
With the help of a great number of participants function models of the Catering organisation were made. With these models the relations between the processes in the Catering could be understood. This was used to discuss the organisation of the material management. The function models were also used to make a simulation model. With the simulation several management strategies were compared. Different loading methods and different intervals between caterers' stock adjustments were tested. These stock adjustments were done with equipment shipments from and to Schiphol, the major KLM hub.
When the there and back travelling passengers on a flight do not match, equipment shortages and surpluses will arise. To prevent this one can supply extra equipment on a flight. This is called 'pre set-up' (PSU). This is done only with equipment used for meals, like trays, plates and cutlery. Three loading methods, with a slightly different definition than the KLM uses, were tested:
1. Variable loading. The amount of equipment loaded is according to the number of passengers on board. In reality only equipment used for meals is not loaded, but in the simulation all equipment was loaded passenger dependent.
2. Semi-variable loading. When more back than there travelling passengers are booked for a flight, the difference is supplied with PSU. In the simulation this was done with all equipment.
3. Full complement loading. This means PSU is supplied for the maximum number of passengers that can be on board. Full complement with max max loading PSU equipment is supplied taking into account that configuration changes can occur. When the simulation was done with full complement loading, the equipment was loaded max max in the case the KLM did that on the same flight in reality. In the simulation all equipment was loaded full complement.
From the research could be concluded that the lowest value of equipment in circulation was realized with variable loading of all equipment. A rough estimate of shipment costs leads to the conclusion that more shipments with less total transported equipment, which occurred with variable loading, is more profitable.
There are two ways to determine the preferred stock levels at the stations:
1. One can experiment by putting surplus stock at some stations and apply variable loading to the flights to and from that station. 2. The simulation model can be expanded so that different hypothesis about the preferred stock levels can be tested.
The first possibility can be performed quickly, the second will probably lead to a better result. In both cases the structural passenger imbalances should be taken into account.
One can also investigate the use of different order intervals for different stations, depending on the number of flights a station has to handle.
The optimal order interval could not be determined with the information about shipments available. It seems wise first to implement the other proposed changes in the material management. Thereafter the order interval can be looked at more precisely.
To accomplish an optimal material management more information should be used. The information should also be used mutually in a formal, structured manner, preferably with one information system. To do that the material management can best be divided into three sections, supervised by one person. The three sections should be responsible for:
1. Purchase and planning. 2. Equipment-flow control.
3. Dispatch and maintenance in warehouses.
The information system should contain a planner designed for the catering equipment flow. The stock levels that caterers give and data about shipments should also be stored herein. In that way answers can be found to the questions about rotability figures and the pipeline. These questions were not answered in this research because no data about the total amount of equipment in circulation was available. By introducing one system an integral approach of the catering logistics can be accomplished instead of sub-optimisation of the sections.
From the simulation was found that a major part of the total value of equipment in circulation is divided over two stocks at Schiphol. These are the equipment holding, where Production Schiphol has its stock, and the central warehouse. Coupling these will reduce the amount of equipment to be in circulation. Three ways exist to manage this coupled warehouse:
2. Combined management of the sections 'Assemblage en afhandeling' and KLM Catering Netwerk.
3. Management by the section Netwerk. The section Production will get a counter for the equipment they need. In this way better insight in the working stock of Production will be obtained.
In all cases purchase and planning should be the responsibility of Netwerk.
A possibility to further reduce the equipment in circulation is moving the parts of Production which use equipment to the warehouse. This way there will be less intermediate stock. Dividing the warehouse according to usage of equipment would be less efficient for the composition of shipments.
Reports on Logistic Engineering (in Dutch)
