Projects:
Here some well-chosen projects are introduced.Technology Foresight in Materials Science and Engineering
In the last ten to fifteen years, technology foresight has become increasingly popular with public organizations. It is a framework and toolset which seeks to take a systematic look at the longer-term future of science, technology and economy, the environment and society with the aim of identifying the emerging generic technologies and the underpinning areas of strategic research likely to yield the greatest economic and social benefits in economies and companies.Roadmaps, scenarios or other "visionary documents" are a vehicle to communicate technology and industry specific potentials (e.g. new markets, employment, national competitiveness) to the public.
The field of material science and engineering is a research area which is characterized by a situation where a great number of experts work in partly congruent disciplines which differ in perspectives. Each discipline and its expert community have a comprehensive overview of tasks and research needs. Many disciplines dispose over a great wealth of research agendas, roadmaps or strategy papers. However, most of the time these lack understanding in the big picture where interdependencies and interfaces are integrated in order to transform research efforts effectively and efficiently into safe and secure new products.
´Strategic Technology Foresight´ can be understood as a linking device not only between the disciplines of process technology and materials but also as a logical interconnection along the lines of a process chain.
This requires a methodical application which will be outlined in the following.
Roadmapping is used as a technique to identify structure and to visualize future tasks in research and development in companies and other institutions. It helps to identify, select and develop technology alternatives to satisfy future service, product or operational needs. Specific Roadmaps, e.g. in smart materials or virtual material design can be the basis for a comprehensive process to identify today’s technology potentials in order to prepare for future market success.
Scenarios describe various potential pictures of the future. Therefore, scenario planning is used as an instrument for long-term planning. It is a framework which is used to identify all relevant influence factors and to analyse their interconnections for a given topic or system. A problem of scenario planning is the fact that it includes many qualitative variables.
The interconnection with Multi-Criteria Decision Making (MCDM), based on mathematical and quantitative methods, can help to complete the comprehensive process, or in terms of modulating societal acceptance. Generally, multi-criteria problems are characterised by the analysis of a great deal of activities (alternatives, solutions, scope of actions, options). The goal is to select or to rate different choices.
Contact: Prof. Dr. Dipl.-Kffr. Dipl.-Ing. Marion Weissenberger-Eibl
Development of Product and Production System
Material science and production engineering move closer together which enables new perspectives for safe, secure and resource efficient products. Consequently numerous interdependencies between products, processes and materials occur. They need to be taken into account during product design. Therefore product planning, product development and production system planning have to be carried out in an interplay. This idea has first been published in the 90s under the term concurrent engineering. However the focus then was an engineering process with overlapping process steps in order to shorten the time to market. In our experience product design cannot be seen as a stringent sequence of phases and milestones. It is more an interplay of activities, which can be subdivided into three cycles: Strategic product planning, product development and production system planning.This first cycle characterizes the steps from finding the success potentials of the future to create a promising product design, which we call the principle solution. There are the four major tasks foresight, product discovering, business planning and conceptual design in this cycle.
The second cycle is product development. It covers the three phases conceptual design, domain-specific concretization and system integration. Within the last phase the domain-specific results are integrated into one overall solution.
The production system planning forms the third cycle. It is carried out in parallel and in a close coordination with the product development. The starting point is the conceptual design of the production system. The result constitutes the starting point for the further process planning, the place of work planning, the working appliance planning and the planning of production logistics.
Within the addressed field of research the aspects of the cycles mentioned before must be adapted for the development of safe and secure structures. Hereby the following challenges arise:
- Developing a design methodology for the integrative development of safe and secure structures and the associated production systems, which takes the numerous interdependencies between product, process and material into account,
- Developing a knowledge based system, which makes domain-specific as well as procedural knowledge available to support designers and production planners during the design process,
- Identifying existing and future areas of application for materials with material-integrated functions and anticipating future costumer demands within the strategic product development. Thereby future materials and production technologies as well as economical and ecological constraints must be taken into account. A methodology for a holistic strategic technology, product and production system planning which has to incorporate the approaches technology push and the market pull.
Contact: Prof. Dr.-Ing. Jürgen Gausemeier
Integrative Product and Material Design
Our current research approach in light weight construction takes as a starting point the analysis of how a product should be designed in order to achieve a minimum weight at reasonable manufacturing costs. Thus, in a first step a component is characterized by defining the desired bunch of component properties, which usually strongly depend on the position within the component. In a second step, the desired properties are related to materials and production technologies, however, because properties of advanced materials and production processes exhibit a strong mutual dependence, both cannot be considered separately. In this sense we focus on very high strength materials, generation of graded properties within components and especially technologies for advanced hybrid structures, where products, materials as well as processes are considered jointly.Currently, hybrid structures in the automotive area are used only in exceptionally cases and the materials combined usually are taken without any special adjustment to the hybrid partner. In addition, the design itself typically starts for example from a given metallic structure where plastics are added. Thus, the construction and overall structure is governed either by one of the partners or by partners who were developed separately. Therefore, the full hybrid potential to achieve symbiotic effects cannot be realized. In order to go beyond the current approaches, we want to define and develop specific material properties, which are designed to make them most suitable especially for hybrid applications. As an example, first studies on hybrid systems consisting of sheet metal and fiber reinforced plastics are manufactured by using special adhesives for joining the materials. However, if the resin systems of the fiber reinforced plastics are refined especially with regard to the hybrid system application, the resin systems themselves could act as the adhesive. Such a hybrid material development concerns not only joining, but also many other areas like joint forming or corrosion protection of hybrid materials. Furthermore, also improved new properties (improved energy absorption in crash events, improved processing properties) could be defined, if real adapted structures are developed.
The scientific challenges concern the optimal adaption and development of different materials and processing technologies with regard to their use in hybrid systems. For this, a new methodology has to be developed. This methodology should start from the definition of product requirements and desired improvements. Then, according to the component properties desired, suitable hybrid materials and production processes must be developed. In the context of lightweight construction, the development of adapted materials should focus on high strength steels and high strength fiber reinforced plastics, faster and large-scale production technologies of the hybrid systems (as for example using Prepreg technologies) as well as new forming technologies.
Contact: Prof. Dr. rer. nat. habil. Thomas Tröster
Intelligent Processing For Complex Product Functions
One highly promising way of reducing the weight of technical components is to make use of multi-material systems. In cases where current materials, in the form of monosystems, come up against material and process engineering limits, the combined use of different materials offers a means of promoting lightweight construction in this field. With the appropriate choice of materials, this material "hybridization" permits weight savings which go beyond those achieved through pure material substitution. This then opens up further possibilities for implementing functions which could result in further weight savings.With the aid of bionic hybrid structures, it is possible to divide up component functions over the specific properties of different materials. This can include the absorption and elimination of forces and moments on the one hand, for instance, and the sealing of a housing filled with media, on the other hand. It would be conceivable to design a lightweight metal frame structure to take bearings and shafts, and also to guarantee a sufficiently high mechanical stiffness. It would then be possible to use plastic components to make this frame structure into a closed housing. Different joining techniques would be feasible for connecting the two materials, such as gluing, injecting the plastic component onto the metal structure or completely overmolding the frame. The choice of process depends to a major extent on the material properties and their processability.
A further aspect then arises from the complex interaction of technology, process choice, process control and material behavior in the above case: the entire plastic production chain, from the raw material to the finished part, ought to be viewed as a whole. It has to be possible to depict this chain in experimental terms with the appropriate methods and also to describe it with simulation methods. The full potential of hybrid and/or bionic component concepts can only be exhausted by overcoming material-typical and process-typical boundaries - such as existing machine concepts and the "customary" processing concepts for material groups. One of the key challenges for the future will lie in identifying the relevant process stages and dividing up processes in such a way that they can be recombined into intelligent process chains or highly integrated processes. This constitutes a major challenge, since, there is no knowledge available, or only an insufficient amount of knowledge available, on the process/material/product interactions for many of the individual process steps. Precisely against the background of process capability and controllability and product reliability, there are a lot of questions that need to be answered in respect of the interdependence of material behavior and process behavior.
Contact: Prof. Dr.-Ing. Hans-Peter Heim
Intelligent Processing: New incremental thermo-forming
Aim of the project is the development of new incremental thermo-mechanical forming-processes with self-inductive heat-generation for the efficient and save production of multifunctional high strength parts with complex geometry using homogenous or heterogeneous material (metallic, organic or inorganic materials). As consequent enhancement of the TR30 thematic this project focuses on the production of complex parts directly from simple semi-finished or precursor materials as well as on the realization of a short, robust process chain. The use of universal tools in combination with new approaches for kinematic shape-generation should be the basis for a save and flexible production.What is new?
A completely new approach is the development of an adequate forming technology for a process capable production of complex, multifunctional Parts and the defined and repeatable adjustment of part properties. Particular demanding is the use of simple semi-finished or precursor materials as basis for a short and robust process chain and a high product quality.
New approaches are necessary for:
- The process planning (reliable planning based on simulation)
- The forming process (high process capability by production in closed loop control scenarios)
- Innovative tool and machine tools (Online-Control of tool-systems and adequate machine structures for the kinematic shape-generation of hybrid materials).
Contact: Prof. Dr.-Ing. Werner Homberg
Process technology for hybrid plastic support structures
In view of the ever-greater shortage of naturally-occurring resources, increasing calls are being made for the development of support structures which are suitable for lightweight construction and which will make it possible to produce electric cars with an appropriate range. Since it is necessary to ensure that newly developed systems meet standardised safety requirements - they will, after all, be in contact with the human species when in use - it is essential to adopt a holistic approach to the process.Employing the GIT-blow process, reinforced zones capable of supporting loads are to be created in specific areas of the part, using polymeric organic sheet. In the GIT-blow process, a preform that has been produced by the gas injection technique during the first process step is inflated to a final part during a second process step. In this second step, the hollow space created by the GIT process has its external contour further expanded in the mould, with the aim of overmoulding the polymeric organic sheets that have been selectively positioned inside the mould. It must be ensured that a bond develops between the parts being joined - through selective activation and the design of the contact surfaces. This can be an adhesive bond, which ought to be created inside the mould through the thermal activation of the expanding plastic support. The proposed idea is set out in diagram form in
Fig. 1.
Contact: Prof. Dr.-Ing. Elmar Moritzer
Multi-functional products/ hybrid material and production concepts
Development of security products and structures is a great challenge for the automotive industry. The introduction of novel materials allows enhancing products, optimizing modern energy management in connection with the weight reduction as well as the energy absorption during impact. Due to the extraordinary properties, composite materials have a great potential for different applications and are regarded as very attractive targets of automotive industry especially with respect to the passenger security. Composite materials with specific functionality are ideal candidates to replace heavier materials in the car. Development of lightweight energy absorbing hybrid materials allowing crash safety or "controlled crush" of car body components is of increasing importance. The goal of security structures during car impact is the crushing in a relatively gradual, predictable way, absorbing much of the impact energy and as a result increasing passenger safety. Incorporation of sensor systems into laminated composites allowing deformation force measurement can increase a complex functionality of car body components. Stiffened laminates and sandwich panels can be effectively used as a light weight protection against collisions and ballistic impact.Contact: Prof. Dr.-Ing. habil. Kurt Steinhoff
New joining and cutting manufacturing processes
Modern products are distinguished by the use of functionally optimized materials and consist usually of different substructures. The processes to produce products of these sub-structures are assembly or joining. By progressive material or functional material development, the joining processes, which are material-dependent also have to be evolved constantly. Therefore, new aspects, such as resource efficiency and adaptability, have also to taken into account. The work theses of the department "tff" "new joining and cutting manufacturing processes for new materials" and "functional integration by joining technology" are thus part of the Cluster objectives.The scientific challenge in the investigation and development of cutting and joining production processes lies in the integration of both technological and strategic issues.
Contact: Prof. Dr.-Ing. Prof. h.c. Stefan Böhm
Polymers: interdependence between material and process
Polymer processing is a scientific area which mainly deals with the modeling, simulation and improvement of production technologies for parts based on polymer materials. But with thermoplastic polymers there is a high interdependence between material properties and the process conditions, which influence each other.Area 1: Polymer Welding
Products with improved properties will consist of different materials, so that each part can be designed with the best possible material. For the combination to the whole product, joining techniques are necessary. One of the most interesting methods is welding, due to the good quality. But welding is a method with high temperature and mechanical load to the material which may change it´s properties. So polymer welding needs research work in the following points
- Welding different materials
- Long time behavior of weld lines
- Techniques for very small interfaces
Area 2: Changing material properties by molecular orientation
Polymer materials change their mechanical properties (stiffness and strength), if their molecules are oriented in space. This is based on modified crystallization or on the simple stretching of the macromolecules. So we can modify the mechanical properties of a part in different areas so that we have non-hybrid-parts with graded properties for improved stiffness or strength on the one hand and less-stiff areas for movements on the other hand.
Compared to the state-of-the-art, we do not know enough about this in high-temperature-resistant materials and we have to learn a lot about the stability of this effects under permanent mechanical load. The processes for molecular orientation in small areas have to be developed and improved. We do not have enough understanding of the relation between the resulting material properties and the process conditions to get them. This is important for getting high stiff and high temperature resistant engineering polymers for light weight construction.
Area 3: Modelling of process and material properties during processing
The carbon-based macromolecules of polymer materials are mainly processed as melt, that means in the small regime between their melting temperature and thermal induced chemical damage. So they will change their molecular weight during processing where they are treated with pressure, temperature and shear stress. This treatment can also be used for chemical reactions. It is supposed that the material´s complexity will rise in the next years, and that further process integration will take place due to the cost effects of these effects. So the material and the process will influence each other.
Modern simulation techniques are necessary for the design of the material and the production process. So understanding these interactions is an important topic for the process modeling. The material laws as constitutive equations for the process modeling are not known and need to be developed. This means the molecular weight development under pressure, shear and temperature for different materials (in which thermal degradation, thermal induced cross-linking or other effects may occur) has to be measured, as well as the reaction kinetics under high pressure.
Contact: Prof. Dr.-Ing. habil. Volker Schöppner
Nanoimprinting for enhanced product properties
Functionalized nanostructured surfaces obtain increasing importance. With decreasing size the conventional fabrication techniques are encountered revealing NanoImprint to be one of the promising techniques. Commercially available NanoImprint templates provide only high lateral resolution (6 nm), thus, high resolution 3D structures cannot be addressed. We have developed sub-nm resolved vertical structures using NanoImprint and wish to apply these structures in research topics adressed by the cluster. Our novel 3D NanoImprint technology enables low-cost material structurization having a size of up to 2" at the moment. 3D NanoImprint allows to repeatedly mould a template into different curable materials and to define nanostructures precisely with a high aspect ratio.As an example a 3D array mesa of different heights (vertical differences in the nm range with total heights in the sub µm range) including 128 different mesa heights have been fabricated. The template has been fabricated using only 7 lithograhic and etching steps. In NanoImprint these templates can be used to generate all the different heights in a single process step with high vertical high-resolution at considerably reduced costs.
Contact: Prof. Dr. rer. nat. habil. Hartmut Hillmer
Local product properties for plastic parts
With a large number of plastics (e.g. fiber-reinforced plastics, highly-filled or conductive plastics, blends/multi-phase material systems, renewable raw materials biologically degradable materials, and functionalized materials), not enough is known as yet about many of the underlying mechanisms relative to the material behavior and its impact on the process and the component properties. It is thus necessary to create a means of permitting the prediction of component properties through interrelated experimental work conducted into natural-science, process engineering and production engineering questions, on the one hand, and into the process description, on the other hand.A typical feature of plastics conversion processes is the simultaneous, thermo-mechanically coupled generation of macroscopic component properties, such as shape and dimensional stability, and micromechanical properties (structure, morphology), right through to molecular nano-scale properties. The locally prevailing micro and nano-scale properties determine the mechanical behavior of the part - this being particularly important for safety-relevant parts (e.g. service life and crash behavior). Processes are generally designed with consideration to the part design and the macroscopic properties. For the increasingly complex, functionalized material and part properties of the future, however, it will be more important to understand the cause and effect chains for the development of local material structures under the actual production conditions for three-dimensional part geometries. Aspects such as the local gradation of properties, the selective adjustment of the mechanical properties of structured parts, or the thermo-mechanical coupling of shaping and structuring are of relevance in this context.
Contact: Prof. Dr.-Ing. Hans-Peter Heim
Safe materials - safe structures
The holistic observation of the entire process chain during part production is essential for the development and production of mechanical and plant engineering components while observing the constraints of high process reliability and guaranteeing both secured and defined properties and a high cost and resource efficiency. By far the largest number of technical innovations in this and other fields is directly or indirectly dependent on the properties of the materials used and the degree of innovation and efficiency of the production technologies employed.Consideration must also be paid to the fact that a direct link exists between applied production processes and local material properties. Of particular importance are the areas close to the surface in the components produced, since it is generally here that key damage and failure processes take place. This also includes the modeling of the relevant process steps, the resultant material structure and the material and component properties that are obtained. A holistic observation of the material, component and process is required here, taking into account structure/property relationships and size effects on different length scales.
Equally important is the development or further development of material characterization methods, both in the field of fundamental research and in the quality assurance of production processes. Only in this way is it possible to optimize the material-, production-, construction- and design-based part properties in a targeted manner, suitably tailored to the load, and to correctly assess the efficiency of specific process steps.
Contact: Prof. Dr.-Ing. habil. Berthold Scholtes
Damage accumulation vs. closed process control loops
The relations between process and performance under mechanical/ thermal loading are closely related to the reliability along the process chain and the information about the materials at each process step. The knowledge that has to be gathered will open up new paths for performance based optimizing of components subjected to mechanical and/or thermal loading. The vision is to establish control loops as an integral part of the processing routine.processing parameters --> microstructure --> -damage mechanisms
--> lifetime --> processing parameters
The scientific challenge lies in understanding the interrelations between the different steps. While there is quite a good understanding of the relations between processing parameters and microstructure in many cases, most models for the damage accumulation process are either purely descriptive or not based on experimental observation. A widespread damage mechanism is crack initiation and growth of micro-cracks. Whereas there is a good understanding of the crack growth phase and its interaction with the microstructure, the mechanisms to crack initiation are less clear. The propensity of a specific micro-structural unit to acting as a crack initiation site depends both on the properties of the unit and on the surrounding microstructure. Moreover, local variations of the micro-deformation field may enhance or suppress crack initiation. Here, both the spatial arrangement of phases and their mechanical properties play an important role. Both quantities depend strongly on the details of the processing routine. Consequently, the complete control loop has to be taken into account, if the crack initiation process is critical for performance-based optimization and lifetime analysis. For metals, some progress has been made in this field over to past few years. However, most efforts were concentrated on high strength materials such as superalloys and less on technical alloys used in mass production. Another interesting new area of application are plastics and fibre-reinforced materials.
Contact: Prof. Dr. rer. nat. Angelika Brückner-Foit
High performance materials for safety-relevant components
Recently, considerable research effort has been directed towards the development of light-weight metallic materials in order to engineer more energy efficient structures without sacrificing safety, which necessitates an increase of the specific strength of the material of interest. This has led to the development of new materials such as TWIP and TRIP steels. However, these materials demonstrate complex microstructures. As a result, both stable processing and safe design of components made of such materials has become more difficult.The use of these steel grades in chassis components is also linked to a change of design concepts since thin walled lightweight structures can no longer be designed using simple material constants such as the fatigue endurance limit. Moreover, critical failure mechanisms such as delayed failure or microstructural instability during cyclic loading have become major road blocks already limiting the use of these advanced materials. In this area the scientific challenges are two-fold. Firstly, one needs to understand the mechanisms that govern the long-term stability of these materials. Given the complex microstructures, this calls for use of advanced in-situ test techniques as the failure mechanisms in these materials tend to occur on a length scale that is typically not accessible by state-of-the-art methods. Secondly, reliable models for such materials need to be developed, which implies complexity of the models. At the same designers will hardly use such models for actual components.
Contact: Prof. Dr.-Ing. Hans-Jürgen Maier
Polymer/ oxide interface stability in composite materials
By means of the combination of computational chemistry of interfaces and experimental interface spectroscopic and microscopic analysis the fundamental mechanisms of de-adhesion mechanisms and kinetics will be evaluated. The aim of the project would be the prediction of the stability of adhesively bonded metal alloys in corrosive environments.The tasks would be as follows:
- Surface analysis of the metal alloy
- Molecular chemistry at the adhesive/oxide/metal interface
- Water ingression in polymer/oxide interfaces
- Measurement of interfacial forces of adhesion
- Prediction of molecular de-adhesion mechanisms and kinetics
Contact: Prof. Dr.-Ing. habil. Guido Grundmeier
Biobased Plastics: a new class of polymers
An alternative to light-weight metallic materials and often a direct competitor in many applications are polymers and polymer composites. These materials, however, are produced mainly from fossil resources with the related consequences on sustainability, resource efficiency, and carbon footprint. Therefore, attempts have been and are being made to change the feedstock to renewable resources and thus contribute to a bio-based economy. The resulting new class of polymer materials includes, among others, polylactic acid (PLA) and polyhydroxyalkanoates (PHA) on the commodity side and biobased polyamides and polyurethanes on the side of engineering polymers. Altogether, these so-called bioplastics still represent a niche market, but achieve growth rates of more than 10 per cent per year. The group of bioplastics is complemented by derivatives of natural polymers like cellulose and starch, and thermoplastic starch formulations. Currently, an appreciable amount of research is directed towards improving mechanical and thermo mechanical properties of these polymers in order to extend the applications from, say, packaging and other short-lived goods on the commodity side to durables and, e.g., automotive applications. In this respect, biogenic reinforcement with natural and man-made cellulose fibers is one option which is followed with remarkable success.What is lacking almost completely today is in depth scientific knowledge on long-term stability and reliability, failure modes and the influence of the changing micro and nano structure on durability. Moreover, bioplastics are often biodegradable under certain circumstances (PLA, PHA) and thus stability considerations appear in a new context. A pre-defined service life with biodegradation as an end of life option may become possible with tailor made copolymers and compound formulations. For fiber reinforced bioplastics in particular, long-term failure mechanisms and the role of the fiber-matrix interphase pose a series of questions requiring scientific investigation. Additionally, in the composite area, bio-based carbon fiber precursors as an alternative to conventional materials raise a lot of scientific attention and should be followed within the proposed research cluster.
Contact: Prof. Dr. habil. Hans-Peter Fink
Complex functionality and intelligent production processes
The reproducible production of such modern security products with complex graded properties and/or integrated special functionalities poses new motivations for the future process design. Common process strategies will fail in the reliable prediction of the process course and its outcome with regard to the safety properties of such components due to their lack in flexibility, online control mechanisms and property prediction methods. New process strategies are needed based on an architecture of editable process control modules and a real time online monitoring with intelligent process visualization to increase the process robustness and reliability. An online visualization of relevant process parameters allows the immediate adjustment in the case of intolerable deviations from the ideal process window or predictable variations of product properties. The control modules represent the entire variety of different basic process characteristics and will be stored in a database. According to the desired product property distribution, a software-based intelligence will ensure the appropriate combination of adequate control modules, which, if required, can be edited in order to refine its parameters and characteristics manually. This implies a self-learning effect of the process control system. The development of this architecture, its intelligence and the identification and implementation of the basic process control characteristics represents the main challenge for future research in the enhancement of process safety and reliability.Contact: Prof. Dr.-Ing. habil. Kurt Steinhoff
Quality control of complex production processes
The reliable processing of innovative security components with a graded property distribution is only feasible, if it is possible to cope with the complexity of the product and the manufacturing process by an appropriate safe quality control. Established methods are inefficient and of no avail in the characterisation of non-uniform microstructures and resulting inhomogeneous properties. A new solution for a quick non-destructive indication of even complex microstructural property distributions with a high efficiency and reliability is unavoidable. Within the transregional research center Transregio 30 a new measurement method based on the different acoustic damping characteristics of locally different microstructures by using an acoustic camera is developed. The enhancement of this quality safety technique towards, on the one hand, more complex sheet metal structures and, on the other hand, further materials especially composite materials poses the scientific challenge.Contact: Prof. Dr.-Ing. habil. Kurt Steinhoff
Process Control for complex process chains
Rising quality requirements coupled with technical products of an ever-greater complexity mean that the steps of polymer processing can no longer be observed in isolation. It is becoming increasingly important to view the process chain in its entirety, starting with the material properties and proceeding via plasticization, mold filling and cooling (e.g. for injection molding), right through to the downstream processes such as refinement and coating, or joining techniques. Each process stage along a production line has an impact on the final result. It is thus only logical, when optimizing the part and the process chain, to make consistent use of all the information that can be made available in the individual process stages.One of the main routes to ensuring greater mastery of the process is process transparency, which can essentially be achieved through the acquisition and assessment of data. It is possible to acquire data from each step of a production line in order to characterize the starting parameters (raw material data, semi-finished product characteristics), the processing operation (process data) and the process results (intensity of quality attributes). Plastics conversion processes are subject to natural fluctuations, however, with the actual values of the raw material data and process data deviating from their setpoint values. Both trends over time and cyclic fluctuations can emerge here, leading to corresponding quality deviations in the molded part.
The target ought to be the observation of quality attributes rather than the observation of specific fluctuating process parameters. With respect to quality related costs and in order to fulfill the requirements of predictive process control it is therefore necessary to model the combined effect of the parameters that exert an influence. Different methods are available for this modeling, including pattern recognition, statistical regression methods, fuzzy logic and neural networks, as well as combinations of these. Each of these methods has its strengths and weaknesses for different fields of application. From the angle of increased process reliability and to ensure product specifications,
It is particularly important to establish how far a method is suitable for process modeling in a specific case and how different methods can be combined in order to cover the whole process chain. In the context of this cluster of excellence, the following main topics should be addressed:
- Real time process modeling for highly integrated complex processes (large parameter set and complex interactions of parameters)
- Modeling of local product properties which may additionally interact (e.g. local internal stresses, local visco-elastic material behavior)
- Both aspects lead to multiple parameter multi criteria problems which are not trivial for process control applications
Contact: Prof. Dr.-Ing. Hans-Peter Heim
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