Jens Bathelt

Performance Factory in the context of mass customization

A novel performance measurement and assessment frame called Performance Factory (PerFact) applied on a specific example focussing on mass customization in the context of the Factory of the Future is presented in this work. PerFact operates target-oriented towards the mission and vision of the company by connecting the overall mission and vision via related requirements with the Key Performance Indicators (KPIs) and their specific reference values. The performance is measured on manufactured customer-driven products, corresponding production processes and used resources. Furthermore, PerFact is able to monitor and assess the performance of both real production systems and simulated production scenarios. Moreover, the measurement system is balanced; it assesses the performance of the factory considering all perspectives relevant for each specific case.

Implications of Modelling One-Dimensional Impact by Using a Spring and Damper Element

Abstract A spring and damper contact force element is often used for modelling impact in multi-body dynamics. The related condition for transition between contact and non-contact is, however, inconsistently implemented in the literature and commercial software. This comparative study aims to clarify the implications of four commonly used transition conditions. Principal differences are discussed and, by simulation of a typical system, it is shown that there are significant differences in the dynamics of the system depending on the different conditions. Two of them give unrealistic contact forces and should imply incorrect prediction of system dynamics in most applications. This suggests that it is important to review results obtained from using these conditions and to eliminate them from commercial software. A discussion of the two other conditions culminates in a recommendation.

Exploitation method for functional product requirements - An integrated function oriented approach

The development of mechatronic products - in particular across the domain borders - is challenging. Possible interdisciplinary improvements are neglected and design inconsistencies are neither prevented nor identified efficiently. Moreover, the complexity of mechatronic products is growing continuously due to an ongoing impact of software on product functions. In addition, the quality of a product is often judged by the quality of its functions. Thus it becomes hard to track the functions of a specific product and how they are realized and the quality of the product functions cannot be assured. Daimler is facing this problem by extending the traditional requirement list with functional requirements in the early design stages. This Function Oriented Product Description (FOPD) is leading to a mature product specification, because it is able to grow and adapt while designing the current mechatronic product and the following product generations of one product family. This work presents a novel approach to gain a benefit directly from the FOPD for the succeeding design process. Therefore the authors provide directions for deriving the so-called Extended Function Structure (EFS) from a FOPD. The EFS is enhancing the traditional function structure by considering sensors, actors and the control logic explicitly. This approach will be exemplified in a case study.

A shoe design support module towards mass customization

The transition from mass production to mass customization has brought new “facts” in the way the different actors of the supply chain do business together. On this context, new business models are being developed and introduced. This work presents a shoe design support module addressing the requirements of the new models for involving more actors such as product and production engineers, suppliers, customers, retailers etc. in the shoe development process. This module fosters the early integration and close collaboration of these Groups of Interest. Furthermore, a novel performance calculation tool is introduced which supports the iterative, collaborative shoe design process by automatically deriving the cost and time values for the new developed shoe model based on the envisioned production processes and the current situation at the production site.

Interacting with real time simulations: virtual reality in industry applications

Modern manufacturing machines are highly multidisciplinary, and with demands on short time-to-market, product development based on traditional prototype testing has become impractical. By using virtual models, it is possible to test large numbers of variants and optimise the product with the aid of a minimum of physical prototypes. Due to the immense development of software and hardware for simulation and visualisation it should today be possible also for small and medium sized enterprises to use methods that just few years ago were too expensive and complicated. There is however still a great need for building knowledge and competence. This work is an early step in a project aiming at a virtual water jet cutting machine to be used by the industrial partner for optimisation during the development process. The possibility of performing real-time simulations of this machine in a virtual environment, using a normal PC and commercial software, will be investigated. Initially strongly simplified models of the system components are used and the focus is on the overall system model and the interaction between the operator and the virtual machine. It is shown that realtime interaction is possible with this system and with the obtained flexibility of the overall virtual model it should be easy to include more realistic component models for improved accuracy in future work. Preliminary results indicate however that to include, for example, flexibility within the mechanic structure, component modelling will be delicate. These models must describe relevant characteristics accurately enough while still being computationally effective enough for real-time interaction and systems optimisation to be possible. This will probably be a challenge in the continuation of the project, even with an expected continued strong development of computer capacity.

Integrated Modeling of Functions and Requirements in Product Design and Factory Planning

A mature management of requirements is seen as a crucial activity within the development of high quality mechatronic products (Heumesser and Houdek 2003; Houdek 2003). Market demands and customer needs have to be captured (Akao 1992). In addition, the company strategy should be considered while designing new products. Moreover, further stakeholders are providing additional constraints, such as legal aspects and production limitations. A holistic approach is desired covering the requirements from every stakeholder spanning from high level strategic goals to low level elementary product functions.