Fraunhofer Chalmers Research Centre for Industrial Mathematics
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A Lean Transformation Journey - A Case Study of the Lean Implementation Process at a Medium-Sized Manufacturing Plant
No full textThe fierce market competition has forced organizations to constantly improve in order to keep up with their competitors and increasing customer demands. Lean manufacturing is a popular improvement strategy for companies to embrace, as it aims to increase the customer value through the removal of wastes in production. However, embracing a Lean philosophy is far from easy, and an insufficient understanding of the Lean concepts and practices is a main cause of the failure rates of 80%.
This study aims to investigate how Lean manufacturing can be implemented into a medium-sized manufacturing plant and the decisive success factors, to define a suitable approach for others who seeks to become Lean. Moreover, the research aims to identify the challenges that arose during a Lean implementation at Gunnebo Entrance Control S.p.A., and the process of solving them.
The results and conclusions of this research are based on an extensive literature review of 65 publications, and a 5-month case study with daily interviews and 500 hours of observations at the shop-floor. To achieve the purpose, the authors have been involved in a Lean transformation project at Gunnebo Entrance Control S.p.A., a manufacturing plant in Lavis, Italy.
The findings demonstrate that Gunnebo was successful in their Lean implementation which is based on improvements validated through increased capacity and improved space utilization, in combination with qualitative assessments from interviews and observations. The challenges faced at Gunnebo were closely connected to change management, which stresses the importance of Lean implementation projects not only possessing appropriate Lean expertise, but also expertise in managing an extensive organizational change. Furthermore, a holistic framework for a successful Lean implementation is presented to assist companies in Lean transformations. The framework suggests lower maturity Lean practices at an early stage to provide short-term success to overcome resistance, and higher maturity Lean practices once a robust Lean foundation has been set. Lastly, following the framework will result in different Lean practices for every company and it cannot be emphasized enough that a Lean transformation, like any other extensive organizational change, has to be adapted to the specific context in order to be successful
Kraftfulla mikroorganismer - En studie om den mikrobiella bränslecellen och dess sensorapplicering inom vattenrening
No full text
A Stochastic Approach for Parameter Relevance Estimation in Vehicle Interior Simulations of Frontal Impacts
No full textThe evaluation of frontal crash performance of vehicles is mainly performed using standardized barrier
tests and the safety system is designed against these. Innovation has led to improved technologies
such as more accurate simulation models enabling us to improve how the safety system can work in
a variety of scenarios. Thus, virtual crash tests using finite elements (FE) have almost replaced the
physical tests among vehicle manufactures. The combination of faster computers and more accurate
models has led to the possibility to simulate the variability in the system performance using stochastic
simulations. If stochastic simulations are performed, which allows for testing of different design options
and variability, information can be gathered as how to create a balanced and optimized safety system
where all components work together at their best. In this thesis, simulations and physical tests
of a currently used car platform are studied in full-frontal crash tests in order to determine which
components need to be represented in the stochastic simulations. Based on the discovered behavior
in theses tests, a list of relevant input and output parameters for the stochastic simulation is defined.
Input parameters are sorted into three different types; production, design and real life, and both risk
injury criteria and kinematics of a crash test dummy are used as output. Furthermore, a simplified and
parameterized FE model of a vehicle interior for frontal impacts is developed and validated. Passenger
airbag and knee airbag are simplified as unfolded airbags and a curve fitting function that measured
the root mean square error between the reference airbag pressure and the simplified airbags is used to
reproduce the behavior of the studied airbags. Floor and windscreen are modeled as rigid surfaces and
the seat is simplified by removing parts of the backrest and prestensioned bolt connections are changed
to rigid. The validation show that the simplified model deviates slightly compared to the studied tests,
but it is approximately 14 times faster compared to the reference. Further, stochastic simulations are
performed with geometrical, impact and airbag parameters varied. The statistical information such
as mean, standard deviation and correlation between parameters is evaluated. The results produced
from the simplified model follows the existing trends in the reference model making it possible to draw
trend-based conclusions from the stochastic simulations. The stochastic simulations indicates that a
crash pulse with low Vehicle Pulse Index is to strive for when developing a car to get low values of
the risk indicators in full frontal impact. In general, the linear correlation matrix is a valuable tool
to see the influence a variation of the input parameters have on the risk injury criteria and dummy
kinematics. Lastly, different ways to present the data, i.e. scatter plots and history curves based
on time data are visualized. In summary, the methodology developed offers an approach for using
stochastic vehicle interior simulations in frontal impact, which can lead to a deeper understanding of
the safety system and the opportunity to optimize and make it more robust
Regional plastic waste recycling through pyrolysis – a techno-economic evaluation
No full textThe aim of this thes is was to investigate the economic feasibility of plastic waste recycling by pyrolysis-based processes on a regional scale. The Gothenburg region was used as a reference regarding the volumes of plastic waste flows. The initial part of the project was a mapping of the regional and national waste flows to see how the amounts of different polymers compare to each other, establishing the possibility of treating certain flows separately. Parallel to this, a literature study was performed to investigate the current processes for treating plastic polymers using pyrolysis.
Four different processes were modelled using the flow-sheeting software Aspen Plus inb oth regional and national scale; one process handling mixed plastics, one handling polyvinyl chloride (PVC) and two handling polystyrene (PS), the two latter being one simpler and one more complex, with different degrees of product separation. With the process layouts established, investment costs, revenues and running costs were calculated for both the regional and national scale plants. A cash flow analysis was conducted to assess the feasibility of regional plastic waste recycling by pyrolysis. The economic performance of regional scale plants was compared to the national scale plants.
The results show that economies of scale have a large impact on profitability and with the current price setting, only the national scale mixed process handling 320 kt/yr shows any potential to raise interest from investors, with a pay-back period (PBP) of seven years. The simpler PS process and the more complex PS process have a PBP of 15 and 17.5 years respectively, the difference mainly arising from the substantially higher investment cost for the more complex process which is not compensated by the extra revenue. The PVC process is nowhere near profitable in any of the cases, mainly due to the complexity of the process and the low value of the products. Even though the national scale mixed process is promising, one drawback is that it does not treat wastes containing PVC, hence leaving the waste management problem with PVC unresolved
