Simulations in the digital factory
SIMULATIONS IN THE DIGITAL FACTORY
The simulation systems for the analysis and optimisation of processes are linked to the concept of the “digital factory“. The Digital Factory (or Virtual Factory or Digital Manufacturing) consists in the mapping of technical and business processes in the digital world to provide advanced support for decisions that are related to product design, process, programming and production control in the real world, through ICT technologies such as augmented reality, simulation, optimisation, etc.
The Digital Factory will be available to users (managers, designers and operators) through a heterogeneous set of software tools that range from CAD / CAM to PLM (Product Life-cycle Management), discrete event simulation to cinematic simulation, virtual reality to augmented reality, from ERP (Enterprise Resource Planning) systems to sequencing and supervision tools.
Although heterogeneous from each other, the information tools of the Digital Factory will be able to interact with each other thanks to the underlying presence of an overall and coherent factory model, which will guide users in using the functions themselves. Each software tool will be able to interact with the factory model by operating on a particular view of the model itself (for example, a logical view in the case of discrete event simulation, a physical and geometric view for virtual reality applications, a chemical/physical/kinematics view for process simulations, etc.).
The interoperability between the tools will be enabled by the use of standards both for information modelling, communication protocols and data exchange methods.
The Digital Factory will be able to take advantage of advanced connectivity at low factory levels for the acquisition of data on machines, order statuses, warranties, personal times, breakdowns and so on. The data acquisition systems of the factory (which are currently part of the MES systems – Manufacturing Execution Systems) will be made directly available to the highest levels of the company and will make intelligent data management and analytical and computational functions possible through the constant updating and maintenance of the digital representation of the factory. To achieve these functionalities, the new production systems will have to review the traditional structure of the automation pyramid (sensors/actuators, PLC, SCADA, MES, ERP).
The Factory Model must be adopted not only in the design phase but also in the operational phase. It will be essential to ensure digital continuity between the real factory and its virtual representation, maintaining consistency between data collected in a heterogeneous way (e.g. production plans, monitoring, demand forecasts, etc.) which contribute to defining the evolution of the production system over time.
The simulation allows for the verification of the functionality of a plant and foreseeing the appropriate management logic. The simulation is particularly useful for verifying the performance of plants, especially prototype plants for any type of use.
The purposes of a simulation of a plant could interest:
- sizing of a storage and handling system in order to identify the surfaces, the means of handling, the bottlenecks, the correct positions of the withdrawal points, sizing of any decoupling buffer;
- sizing of work stations to meet production capacity;
- evaluation and verification of the dynamic behavior of the plants;
- evaluation of production efficiency of potential automation solutions
Warehouse management in the world of logistics has become a fundamental asset in the management of the industry.
The complexity reached by distribution systems that are scattered all over the world to be able to cover ever-increasing areas generates problems and situations that go beyond the calculation possibilities of the old static methods. This means that the use of dynamic simulation software is absolutely necessary.
The simulation applied to warehouses allows you to accurately identify performance. The simulation can be applied to manual warehouses (with forklifts guided by operators) and also to automatic warehouses with stacker cranes, multi shuttles, satellites etc …
The simulation of an automatic or manual warehouse helps to identify the critical areas and bottlenecks or any eventual congestion areas that if not modified will become critical areas of the system compromising its functionality. Any plant modifications may require the modification of the kinematics of a plant, the variation of the number of machines (stacker cranes, self-propelled machines, shuttles, etc …).
CONTINUOUS FLOW LINE SIMULATIONS
The continuous flow production lines consist of a succession of interconnected stages. Each stage performs a process or an aggregation. The transport is usually carried out with roller or chain belt conveyors, in general by an automatic system. The transport system also acts as a decoupling buffer between the various stages. The buffer capacity between successive stages must be suitably sized to absorb inefficiencies caused by machine downtime, tool changes, jams or any other impediments.
Flow lines are also often subject to format changes. The number of formats managed in the line places two types of complications on this type of line: management and sizing. From the management point of view, it is necessary to make the right assessments on the line set-up times which are a function of a setup matrix. From the sizing point of view, it must always be kept in mind that it must be evaluated for each format that the line will have to process. All these complexities are addressed in a simulation of a flow line.
The simulation allows to optimise the line thanks to an appropriate sizing of the inter-operational buffers and also of the various production stages, even according also to the format that the line produces.
JOB SHOP FLOW SIMULATIONS
A manufacturing process can be simulated for the following reasons:
- verify the production capacity of a process;
- verify the possibility of the system or plant to cope with a pre-established production plan
- verify the possibility of fulfilling customer orders
- determination of specific processing times for each product at each stage of the process
- determination of the setup matrix for each stage of the process from product to product
- determination of the MTBF / MTTR reliability parameters for each stage
- determination of waste coefficients for each stage
- determination of batching criteria