Helmut Bley

Appropriate human involvement in assembly and disassembly

Product assembly as well as disassembly is often carried out by workers who have been trained and are flexible with respect to the different variants, delivery dates and changing lot sizes. Though there has been a strong tendency to mechanize and automate production during the last years many operations in assembly and disassembly are still very often performed manually. Furthermore there might be an increase in manually operated assembly or disassembly as a result of product equipment investments with shorter usage time. This keynote paper deals with the state of practice as well as the tendencies in product and production technology and the influence of markets. Another question is going to be the use of information technology on the shop floor level and between the shop floor and other levels within a company as well as the customers. Therefore industrial engineering is increasingly dealing with the influence of organization and structuring of production processes.

Integration of Product Design and Assembly Planning in the Digital Factory

Abstract As assembly process planning fulfils the main function of connecting product design to production simulation and thus, the production system itself, a feasible software solution is needed to support this process. Thus, a novel concept is presented that aims at improving the integration of digital product design and assembly planning by introducing a consistent data structuring. This approach helps to reduce redundant tasks and supports the continuous data exchange. It is based on the use of assembly features, i.e. pre-defined geometry elements that contain additional technological information. The prototypical implementation of the concept focuses on the use of commercially available software tools, expanding them with additional functionality for the application of assembly features. The feature-based concept has been tested with a scenario from the automotive supplier industry. For the considered assembly, a comparison between the conventional and the feature-based planning approach is presented in the paper. It points out that the major advantages of the developed concept can be seen in an improved data consistency as well as a higher level of efficiency within the planning activities.

Variant-oriented Assembly Planning

To remain competitive, companies have to fulfil the requirements of their customers for individualised products of high quality. Thus, they have to become capable of managing the continuously rising number of product variants, especially in assembly planning. As the current variant management concepts are not adequate, this paper deals with a novel approach towards an integrated consideration of all required product and process variants. A generalised product description that can be enhanced with assembly features represents an optimal initial point for assembly planning. The implementation of so-called variant junctions allows for the regard of variants within the planning of the required assembly processes.

Distributed Simulation Applied to Production Systems

Abstract To run nowadays production systems in an optimized way complex and time consuming models are helpful especially if an isolated analysis of subsystems is not possible. Operating problems like scheduling and resource requirement planning need short processing times while strategic problems lead to a large number of solutions to be evaluated. This paper proposes the problems to be solved and a modeling and simulation architecture that allows the use of distributed computer resources and databases. The approach of separated modeling and simulation allows a better performance. By a distinct example it is shown how this approach can be used for the optimization of storage using the eventdriven material flow simulation.

Distributed model management system for material flow simulation

Abstract Several concepts to increase the efficiency of modelling processes for simulation such as the use of specialised simulation tools, model integration, implementation of reference models and model reuse are discussed. Systems similar to existing model management systems (MMS) are postulated for simulation of production systems. A prototype MMS for material flow simulation is presented by describing its distributed architecture, its application during the modelling process and as an optimisation tool. Substantial advantages of this new MMS are the support of distributed planning teams and a higher efficiency of the modelling process by multiple use of simulation models. Finally, experience from an industrial test phase is discussed and requirements for the industrial operation of the system are derived.

A tolerance system to interface design and manufacturing

In this article the concept and a prototype of a feature based integrated tolerance support system is described. The system consists of a “functional view” and a “manufacturing view” onto the tolerances. The “functional view” supports the designer finding appropriate solutions concerning dimensions and tolerances for certain functions like “bearing seat” or “transfer torque”. The “manufacturing view” contains information about the feasibility, production cost and time of a tolerance. This knowledge based on experiments is stored in a SQL database. The manufacturing information is given to the designer and he/she can alter his/her decisions in a very early phase of the design process if problems arise. Implementation platform of the fully CAD integrated support system is CoCreate’s SolidDesigner.

Process-based assembly planning using a simulation system with cell calibration

When using simulation systems in assembly planning, a considerable gap between simulated accuracy and real environment can often be detected. As an approach to bridge this gap, a cell calibration method based on measurements by a laser triangulation sensor is presented. The sensor system is mounted on an industrial robot and delivers the relevant data to the simulation system. Thus it is possible for the simulation system to calculate the change in position and orientation compared to the original model of the cell. This method eliminates the teaching effort that is required to adapt the simulation-based robot program to reality when using a conventional assembly planning method. Furthermore, it enables the user to derive the layout of assembly system directly from the process model with a high level of accuracy and to considerably reduce the time-to-market.

New Strategies and Tools for Increasing Simulation Efficiency

Abstract In recent years, the progress of simulation technology led to modeling software showing a very high level of perfection and functionality. However the expense of modeling has held the number of users lower than original expectations. The central idea to increase acceptance is the multiple use of simulation models. Based on this perception, comprehensive strategies have been developed for three different kinds of simulation projects: small/standardized, spontaneous and large/long-running projects. These strategies are supported by tools for planning and implementation of efficient simulation projects. The methods and tools have been implemented to prove their feasibility in event-driven material flow simulation.

Solving technical problems in assembly system's design

Abstract The design of an assembly system leads to very difficult technical problems in which technological, functional and economical aspects must be considered. The designers experience represents a crucial portion of the information which has to be made available. Another part of the needed information is contained in the product design, and part of it is provided by suppliers of assembly system components. Problem solving based on information incorporated in assembly features will be demonstrated using problems encountered in an existing assembly system. The characterisation of features related to assembly is a research topic at the Saarland University. Preliminary results of a contribution to feature-based CAD-systems will be presented.

Future Challenges in Process/Resource Planning Due to Increasing (Product) Variants

Factories that are flexible in production and cost-efficient are needed. But obviously, it is not so easy to plan/realise such factories — the complexity of the task increases with every additional (product) variant to be considered. All fields of the production engineering process are affected by the above-mentioned complexity problem. But, this paper only deals with shortcomings/challenges within the first steps of production planning. Future planning experts need suitable concepts to perform their tasks in an easier, faster and more precise manner. The transparency within production planning has to be improved in order to simplify decision making.