Ökonomische Prozessanalyse und Modellintegration zur Kostenberechnung von Faser-Kunststoff-Verbunden
- The introduction to the topic is a description of the techno-economic evolution of
composites. Apart from this, today’s market state of the art of composites is also explained.
As a conclusion, the principal trend towards the higher quality by the increased
application of carbon fibers is ascertained. In particular, it is pointed out that
the restraints of the market growth are mainly caused by the high price, most notably,
of the fiber materials. This situation, in connection with the maturation of the composite
manufacturing processes, demands the need of a cost calculation tool.
In the second step, former composite cost models and their implementations into
software – if available – are described and benchmarked. As a result it is proposed to
combine, different approaches because of their fundamental potential as well as the
deficits. It is suggested to use a resource-based methodology combined with the
PBKM (prozessbasierte Kostenmodellierung = process-based cost modelling) and to
implement the models in a cost calculation software.
The first aim is an economic process analysis which is carried out to receive an abstract
and modular system. Thereby, it is possible to describe the production processes
by successive refinement more and more detailed. The process is divided in
multiple steps which are itself subdivided in technical activities or handlings. The
relevant cost objects with the identifiable cost positions are assigned to those handlings.
This approach assures modularity and offers the possibility of an easy software
implementation. In addition, the functionality of this methodology is demonstrated
considering the two examples “thermoplastic tape placement” and “continuous
pressing”. For that reason these composite manufacturing techniques are analyzed
and the structure is mapped within the use of suggested methodology.
The next topic deals with the modelling of the cycle time for the thermoplastic tape
placement with the use of the PBKM. Within this methodology the derivation of the
cycle time depends only on physical process parameters, which results in a geometrical
complexity based model. The developed model is verified by comparing of the
theoretically derived values with practical experiments. Along with this, the assumptions
for this model are revised and verified. As a technical enhancement of the tape
placement process, different designs of a geometry-adaptive consolidation role are introduced. This technical extension of the process technology is necessary for the
final verification of the model. The new consolidation unit enables to move all geometrical
degrees of freedom and complexities with the same laminate quality. Finally,
a possibility to transfer the methodology of the PBKM to other technologies is proved.
Therefore, it is offered a modus operandi how the continuous pressing technique can
be modelled with the help of the PBKM.
The last chapter deals with the cost calculation tool concerning the structural configuration,
design, and functionality of the software. It is the consequential synthesis of
the results of the economic process analysis and the cycle time models. The practicability
of the modularity is proved by its application in the design phase of the software
and by the integration of the modelling into the tool. The developed cost calculation
software for composite manufacturing processes offers a standardization of the
inputs and calculation algorithms by the use of introduced process analysis, the subdivision
into smallest units. The cycle time calculation models are process specific
know-how which can easily be used unlike an expert's system. The separation of the
single functional entities assures a stringent data management, possibilities for the
advancement, and furthermore, the variableness of representation and reuse of the
derived data. The functionality of the cost tool concerning evaluations and comparisons
are pointed out with two case studies. Plus, the postulated transferability of the
methodology on other composite technologies is demonstrated. The main advantage
of this system is that the modelling offers economical statements of different process
variations without experimentation. Besides, the values ascertained by the PBKM are
more precise compared to other existing models. Therefore, the PBKM can be the
basis for investment decisions like technology change or modifications and helps to
identify techno-economic limitations and potentials.
This version of the cost calculation software offers only the standard repertoire of
cost evaluations and comparisons which turn out to be upgradeable. Thus, there exists
potential to enhance the functionality concerning sensitivity analyses, the integration
of cycle time models for other composite processing technologies, and further
possibilities for the graphic processing. As a conclusion the software with the combination
of different attempts offers a good starting position with respect to the current
evolution status and should be extended.