A responsive automotive manufacturing plant producing a large range of vehicles with a dynamic demand profile has been simulated using discrete event simulation software. The facility is based on a matrix structure and a modular construction paradigm. Results show that it is possible to achieve high levels of equipment utilisation while building a large range of vehicles through a single facility and that this gives high levels of volume flexibility for all models. Other benefits can also be realised from this approach including-
Attempts to compare costs for such a facility with similar traditional methods have however been less successful. While published figures for existing plants clearly show the losses incurred by an inability to handle large demand fluctuations it has been impossible to cost up a generic production system. Companies have either been unwilling or incapable of divulging cost models for existing facilities let alone a novel concept such as RAMP. While we remain convinced that the gains from such an approach can out weigh the extra cost involved any comparison would need to be done using specific data for a real project. A cost framework exists to allow this but this would invariably require some modification for case specific detail.
Unfortunately at this moment in time although most of the vehicle manufacturers active in the UK have shown an interest in this approach none are currently ready to adopt such a radical approach. The project will therefore not be moving forward to looking at a real facility at this stage. It is however hoped that this will happen at some stage in the near future. It is intended to publish the findings more widely over the next 12 months with a view to attracting partners to take the concept to the next stage.
The Responsive Automotive Manufacturing Plant (RAMP) concept was developed in direct response to the perceived threats to and weaknesses of the UK Automotive Industry.
A flexible, matrix style production system was proposed that meets these requirements and allows new vehicles to be launched without disruption to current production and with minimal facility investment. The concept utilised many of the design features currently being tried by major automotive companies but was rather less conservative in the way they are applied.
RAMP is based on a matrix of cells rather than the traditional linear assembly system. It moves the body-in-white vehicles through individual process cells in which all the vehicle’s structure, system modules, core components and optional fittings are attached to achieve a specified model build. In a conventional linear system any shortages of parts, equipment breakdowns or stoppage for maintenance can force the whole line to stop, however a RAMP system will divert vehicles from a non-working cell to a working one and maintain a continuous flow of production. RAMP can also accommodate a wider range of customisation options and model variations, allowing cars to be built-to-order.
The increased flexibility inherent in the matrix assembly system also allows variations in the production volumes of each vehicle per shift. Long-term variations are accommodated by the addition of cells when required, rather than paying for all the equipment at the beginning of the project.
The RAMP system also provides increased capital utilisation and an ability to continually build new concepts or prototypes without compromising production figures.
A facility incorporating the RAMP method was modelled using QUEST Software; a flexible object based environment in which to build and modify discrete event simulations of manufacturing facilities. The production rates were based on forecasts produced from the SALVO project (details are shown in Table 1). A typical (though static) pictorial output is shown in Figure 1.