Klaus Feldmann

INNOVATIVE DISASSEMBLY STRATEGIES BASED ON FLEXIBLE PARTIAL DESTRUCTIVE TOOLS

Abstract Recycling concepts, as they are required in the actual waste management legislation, often need the development of disassembly processes to assure, i.e. an efficient separation of hazardous materials, or the accumulation of worthy ingredients for further recovery. Therfore methods and tools have to be found in order to determinate law-conformal and economic disassembly strategies. Further efficient disassembly processes and tool have to be developed, considering the specific requirements. In this contribution is given an overview of the actual German legislative situation regarding waste management. After an analysis of the caracteristics of disassembly an approach for computer aided disassembly planing is presented. In the last part of the paper are shown some innovative disassembly tools.

Specification, design, and implementation of logic controllers based on colored Petri net models and the standard IEC 1131. I. Specification and design

This work aims at designing and implementing logic control structures that allow a combination of the advantages of classical techniques for the development of programmable logic controller code and elimination of disadvantages such as the lack of formal validation. This paper introduces ordered color Petri nets in combination with some extensions as a modeling tool for logic controllers. The validation of both the model and the specifications of the logic control structures is then pursued through a structural analysis of the net. A special compiler that generates code according to the standard IEC 1131 is discussed. The modeling and implementation of a logic control system of a sector of a flexible assembly cell serves as an example.

Closed loop quality control in printed circuit assembly

Almost 30-50% of fabrication costs in electronics production are caused by testing and repair operations. The reasons for that problem are many. First of all, there is still a lack of knowledge concerning the conditions for robust process control. On the other hand, uncertain specification of product quality causes unnecessary inspection, testing, and repair actions. Thus, a strategy for yield improvement requires strong dedication to causal relationships and specification of process and product quality. In the first step, critical process parameters and their causal effects on product quality must be analyzed. In the second step, once critical process parameter are addressed, control strategies can be developed to assure high first pass yields. This paper gives an overview of ongoing work that has been performed to establish a SMT production line with closed loop quality control via direct process monitoring capabilities and integrated inspection operations. For different inspection tasks, 3-D laser and X-ray inspection is applied. Process parameters as well as test and inspection results are gathered on line. Thus, interrelationships between different process steps, beginning from material inspection, solder paste application, components placement, reflow soldering, and final inspection, can be analyzed. Moreover, variation of process parameters conforming to different approaches to design of experiments (DOE) can be performed while running production. On-line diagnosis of process parameters and inspection results enables a closed loop quality control. >

Modularised, distributed real-time control of flexible production cells, using petri nets

Abstract The main goal of this work is the design of a real-time scheduler for cotrolling flexible production cells using an extension of Petri nets. The approach comprises a modularisation of a Petri-net, which models the different resources of the cell under study. This leads to the design of a distributed discrete-event control system, which is built up of three main structures, the coordination system, and the local and complex controllers for solving conflicts. The dynamics of the proposed control system is operated by means of an application protocol, which allows for coordination and synchronisation between both controllers. The validation of this approach is shown on an example application.

Computer-aided planning systems for integrated electronic and mechanical design

The data processing requirements that arise when integrating housing and circuitry by means of three-dimensional molded interconnection devices (3-D-MIDs) are addressed. An overview of these requirements is given, and promising steps for integrating the functionality of CAD systems for electronic (ECAD) and mechanical (MCAD) applications are described. >

Monitoring of flexible production systems using high-level Petri net specifications

Abstract The degree of reliability in the operation of flexible production systems depends not only on the operation of the individual components, but also on the structure and evolution of the embedded supervisory control system. Monitoring of operations and of the behaviour of the components and of the system as a whole is an essential function of such a supervisory control system. This paper focuses on the development and implementation of feature- and model-based monitoring methods using high-level Petri net specifications of flexible production systems and of the embedded discrete-event controllers. The combination of machine–human interface concepts with the developed monitoring methods leads to a user-friendly representation of monitoring information. An application at industrial level is shown by means of a case study, i.e., a sample flexible assembly cell, situated at the Institute for Manufacturing Automation and Production Systems, Germany.

Specification, design, and implementation of logic controllers based on colored Petri net models and the standard IEC 1131. II. Design and implementation

This work aims at designing and implementing logic control structures that allow a combination of the advantages of classical techniques for the development of programmable logic controller code and elimination of disadvantages such as the lack of formal validation. This paper introduces a method to automatically generate code for a programmable logic controller from a validated textual description of this kind of Petri nets. A special compiler that generates code according to the standard IEC 1131 is discussed. The modeling and implementation of a logic control system for flexible assembly cell using the method describe serves as an example.

Design of a theoretical holistic system model as base of construction kits for building Plug&Produce-able modular production systems

With the aim of creating flexible and variable production systems, the concept of Plug&Produce contributes to changing markets. Increasing product diversity entails increasing mixes to be produced. Thus, flexibility in adapting production quickly to fluctuating demands in functionality and performance is required. The associated shortening of life cycles involves the requirement of variable production systems structures. To solve these tasks, holistic concepts are necessary on whose basis construction kits can be created which are necessary to built up those kinds of production systems. These concepts must all-embracing cover physical structure, processes and energy supply as well as process-, flow- and logistic-control. Since we are convinced that without a theoretical fundament this task cannot be accomplished, we present a holistic system model, based upon both, the analysis of the general system theory and the analysis of controlled systems.

MID in the automotive industry-potentials, benefits and applications

Molded interconnect device (MID) technology integrates electrical and mechanical functions into a single molded part. A variety of methods is available for manufacturing MIDs. Depending on the application, the use of MID technology allows more than 20% in cost savings over conventional technologies, as proven by several examples. MIDs boast a wide field of applications in an automobile and have been sucessfully used in several cases.

Design of a formal model for the specification of agent platforms based on Plug&Produce-able production systems

The optimal dispatching of orders to the production system and the assignment of workpieces to machines is influenced by numerous disturbances at run time, which can neither be foreseen nor regarded in every detail with conventional strategies for coordination. Often, workflows are defined manually and therefore they implicate problems in adapting to changed situations. To provide the maximum flexibility in exceptional situations, the concept of Plug&Produce is combined with the agent technology. The presented Plug&Produce-principles provide the fast build-up of production plants with construction kit elements, which consider the flow of material, energy and information in common. On top of this, extended functionality is featured by agent technology for the organisation and optimization of process steps. In this paper a formalism and system definition is derived from the Plug&Produce system model for the clear specification of an agent, its internal structure and external behaviour towards other agents and the real world. This is the basis for the further development of a continuous agent platform directly applied in the control system on shop floor.