Contact Graphs in Multibody Dynamics Simulation

For this costumer placed in Belfast, UK, simulation has been used to investigate the manufacturing process, to evaluate bottlenecks and to prepare the background for simulation based, in-line scheduling. The actual problem at the shop floor deals with synchronizing work flows and optimizing production in conjunction with customer orders . Over 1700 different kinds of orders can be manufactured at the shop floor and the first task in building the model, was to separate the wide amount of different types of products into main groups. Using the simulation model in connection with more advanced scheduling tools, production managers expect significant improvements of the production efficiency, obtained by reducing the waiting time in queues and by increasing the usage of the resources. Overview of the manufactur ing at the shop floor At the shop floor metal sheets are stored in automatic storage/retrieval system (FMS) that feeds all of the 6 punching machines. Generally products are completed on one machine however there is flexibility to allow component transfer between machines for breakdowns. After punching, the steel is returned into the FMS, then the punched parts are brought to any of 14 folding machines. All machines need an operator full time. Furthermore each machine is manned at all time with an additional operator, or trainer, per shift to help facilitate 2 man operations for some of the larger components. Next step is welding: since the work here is done manually, the capacity depends on the number of workers allocated to this section. The absolute maximum of workers working in this section at the same time is 17. Then there is a fettling process, again capacity depending on the number of workers, the maximum being 12 per shift. Next, there are two paint lines, moving at constant speed. The paint line conveyer speed can be adjusted to suit capacity requirements. The maximum number of operators required per line is 8 for loading and unloading and 4 for the painting operation. The paint lines do stop every hour to allow the changeover of personnel, also due to the complex nature of the product the paint lines are stopped on a regular basis to allow the painters to touch up the more complex products. The painted parts are then moved to two assembly lines and to a nutserting area. The personnel on the paint line stagger lunch breacks so that the line can run continuously. The parts once nutserted are then moved into and out of dispatch. Maximum number of operators in the nutserting area is 5 per shift. The two assembly lines are designed for mixed model