Improvement of Operational Efficiency effectiveness (OEE) using Six Sigma DMAIC Methodology — Case Bottomer line AD2378

Overall Equipment Effectiveness (OEE) is the key metric of operational excellence. OEE monitors the actual performance of equipment relative to its performance capabilities under optimal manufacturing conditions. It looks at the entire manufacturing environment measuring, in addition to the equipment availability, the production efficiency while the equipment is available to run products, as well as the efficiency loss that results from scrap, rework, and yield losses. The analysis of the OEE provides improvement opportunities for the operation. One of the tools used for OEE improvement is Six Sigma DMAIC methodology which is a set of practices originally developed to improve processes by eliminating defects. It asserts the continuous efforts to reduce variation in process outputs as key to business success, as well as the possibility of measurement, analysis, improvement and control of manufacturing and business processes. In the case of the Bottomer line AD2378 in Papsac Maghreb Casablanca plant, the OEE figures reached 48.65 %, which is below the accepted OEE group performance. This required immediate actions to achieve OEE improvement. This Master thesis focuses on the application of Six Sigma DMAIC methodology in the OEE improvement on the Bottomer Line AD2378 in Papsac Maghreb Casablanca plant. First, the Six Sigma DMAIC and OEE usage in operation measurement will be discussed. Afterwards, the different DMAIC phases will allow the identification of improvement focus, the identification of OEE low performance causes and the design of improvement solutions. These will be implemented to allow further tracking of improvement impact on the plant operations.

Energy efficiency parameters in variable speed drives

The main purpose of this thesis is to measure and evaluate how accurately the current energy saving calculation in ABB’s new variable speed drive ACS850 works. The main topic of this thesis is energy-efficiency parameters. At the beginning of this thesis centrifugal pump, squirrel cage motor and variable speed drive, including some equations related to them, are being introduced. Also methods of throttling control and variable speed drive control of centrifugal pumps are being introduced. These subjects are introduced because the energy saving calculation in ACS850 is related to the centrifugal pumps usually driven by squirrel cage motors. The theory also includes short section about specific energy of pumping. Before measurements the current energy saving calculation of ACS850 is being introduced and analyzed. The measurements part includes introduction of measuring equipment, measurement results, summary and analysis of the measurements. At the end of this thesis a proposal for an improvement to the current energy saving calculation is being introduced and few proposals are made for new energy-efficiency parameters, which could be added to variable speed drives. At the end are also thoughts

Enhancing the efficiency of freight transport by using simulation

The role of transport in the economy is twofold. As a sector of economic activity it contributes to a share of national income. On the other hand, improvements in transport infrastructure create room for accelerated economic growth. As a means to support railways as a safe and environmentally friendly transportation mode, the EU legislation has required the opening of domestic railway freight for competition from beginning of year 2007. The importance of railways as a mode of transport has been great in Finland, as a larger share of freight has been carried on rails than in Europe on average. In this thesis it is claimed that the efficiency of goods transport can be enhanced by service specific investments. Furthermore, it is stressed that simulation can and should be used to evaluate the cost-efficiency of transport systems on operational level, as well as to assess transportation infrastructure investments. In all the studied cases notable efficiency improvements were found. For example in distribution, home delivery of groceries can be almost twice as cost efficient as the current practice of visiting the store. The majority of the cases concentrated on railway freight. In timber transportation, the item with the largest annual transport volume in domestic railway freight in Finland, the transportation cost could be reduced most substantially. Also in international timber procurement, the utilization of railway wagons could be improved by combining complementary flows. The efficiency improvements also have positive environmental effects; a large part of road transit could be moved to rails annually. If impacts of freight transport are included in cost-benefit analysis of railway investments, up to 50 % increase in the net benefits of the evaluated alternatives can be experienced, avoiding a possible inbuilt bias in the assessment framework, and thus increasing the efficiency of national investments in transportation infrastructure. Transportation systems are a typical example of complex real world systems that cannot be analysed realistically by analytical methods, whereas simulation allows inclusion of dynamics and the level of detail required. Regarding simulation as a viable tool for assessing the efficiency of transportation systems finds support also in the international survey conducted for railway freight operators; operators use operations research methods widely for planning purposes, while simulation is applied only by the larger operators.

A Practical Micro Mechanical Model Based Local Approach Methodology for the Analysis of Ductile Fracture of Welded T-Joints

This thesis concentrates on developing a practical local approach methodology based on micro mechanical models for the analysis of ductile fracture of welded joints. Two major problems involved in the local approach, namely the dilational constitutive relation reflecting the softening behaviour of material, and the failure criterion associated with the constitutive equation, have been studied in detail. Firstly, considerable efforts were made on the numerical integration and computer implementation for the non trivial dilational Gurson Tvergaard model. Considering the weaknesses of the widely used Euler forward integration algorithms, a family of generalized mid point algorithms is proposed for the Gurson Tvergaard model. Correspondingly, based on the decomposition of stresses into hydrostatic and deviatoric parts, an explicit seven parameter expression for the consistent tangent moduli of the algorithms is presented. This explicit formula avoids any matrix inversion during numerical iteration and thus greatly facilitates the computer implementation of the algorithms and increase the efficiency of the code. The accuracy of the proposed algorithms and other conventional algorithms has been assessed in a systematic manner in order to highlight the best algorithm for this study. The accurate and efficient performance of present finite element implementation of the proposed algorithms has been demonstrated by various numerical examples. It has been found that the true mid point algorithm (a = 0.5) is the most accurate one when the deviatoric strain increment is radial to the yield surface and it is very important to use the consistent tangent moduli in the Newton iteration procedure. Secondly, an assessment of the consistency of current local failure criteria for ductile fracture, the critical void growth criterion, the constant critical void volume fraction criterion and Thomason's plastic limit load failure criterion, has been made. Significant differences in the predictions of ductility by the three criteria were found. By assuming the void grows spherically and using the void volume fraction from the Gurson Tvergaard model to calculate the current void matrix geometry, Thomason's failure criterion has been modified and a new failure criterion for the Gurson Tvergaard model is presented. Comparison with Koplik and Needleman's finite element results shows that the new failure criterion is fairly accurate indeed. A novel feature of the new failure criterion is that a mechanism for void coalescence is incorporated into the constitutive model. Hence the material failure is a natural result of the development of macroscopic plastic flow and the microscopic internal necking mechanism. By the new failure criterion, the critical void volume fraction is not a material constant and the initial void volume fraction and/or void nucleation parameters essentially control the material failure. This feature is very desirable and makes the numerical calibration of void nucleation parameters(s) possible and physically sound. Thirdly, a local approach methodology based on the above two major contributions has been built up in ABAQUS via the user material subroutine UMAT and applied to welded T joints. By using the void nucleation parameters calibrated from simple smooth and notched specimens, it was found that the fracture behaviour of the welded T joints can be well predicted using present methodology. This application has shown how the damage parameters of both base material and heat affected zone (HAZ) material can be obtained in a step by step manner and how useful and capable the local approach methodology is in the analysis of fracture behaviour and crack development as well as structural integrity assessment of practical problems where non homogeneous materials are involved. Finally, a procedure for the possible engineering application of the present methodology is suggested and discussed.

Performance Improvement of Centrifugal Compressor Stage with Pinched Geometry or Vaned Diffuser

Centrifugal compressors are widely used for example in refrigeration processes, the oil and gas industry, superchargers, and waste water treatment. In this work, five different vaneless diffusers and six different vaned diffusers are investigated numerically. The vaneless diffusers vary only by their diffuser width, so that four of the geometries have pinch implemented to them. Pinch means a decrease in the diffuser width. Four of the vaned diffusers have the same vane turning angle and a different number of vanes, and two have different vane turning angles. The flow solver used to solve the flow fields is Finflo, which is a Navier-Stokes solver. All the cases are modeled with the Chien's k – έ- turbulence model, and selected cases are modeled also with the k – ώ-SST turbulence model. All five vaneless diffusers and three vaned diffusers are investigated also experimentally. For each construction, the compressor operating map is measured according to relevant standards. In addition to this, the flow fields before and after the diffuser are measured with static and total pressure, flow angle and total temperature measurements. When comparing the computational results to the measured results, it is evident that the k – ώ-SST turbulence model predicts the flow fields better. The simulation results indicate that it is possible to improve the efficiency with the pinch, and according to the numerical results, the two best geometries are the ones with most pinch at the shroud. These geometries have approximately 4 percentage points higher efficiency than the unpinched vaneless diffusers. The hub pinch does not seem to have any major benefits. In general, the pinches make the flow fields before and after the diffuser more uniform. The pinch also seems to improve the impeller efficiency. This is down to two reasons. The major reason is that the pinch decreases the size of slow flow and possible backflow region located near the shroud after the impeller. Secondly, the pinches decrease the flow velocity in the tip clearance, leading to a smaller tip leakage flow and therefore slightly better impeller efficiency. Also some of the vaned diffusers improve the efficiency, the increment being 1...3 percentage points, when compared to the vaneless unpinched geometry. The measurement results confirm that the pinch is beneficial to the performance of the compressor. The flow fields are more uniform with the pinched cases, and the slow flow regions are smaller. The peak efficiency is approximately 2 percentage points and the design point efficiency approximately 4 percentage points higher with the pinched geometries than with the un- pinched geometry. According to the measurements, the two best geometries are the ones with the most pinch at the shroud, the case with the pinch only at the shroud being slightly better of the two. The vaned diffusers also have better efficiency than the vaneless unpinched geometries. However, the pinched cases have even better efficiencies. The vaned diffusers narrow the operating range considerably, whilst the pinch has no significant effect on the operating range.

Analyzing the cost-efficiency and performance of a payroll department by benchmarking

Tämän diplomityön tavoitteena oli analysoida Stora Enson palkkakeskuksen ja sen henkilöstöhallinnon järjestelmän, SAP HR:n, kustannustehokkuutta ja suorituskykyä. Tutkimuksessa käytettiin apuna benchmarkingia. Viisi suurta suomalaisyritystä osallistui benchmarkingiin. Benchmarkingin pääkohteena oli yritysten välinen kustannusvertailu. Kyselyssä perehdyttiin myös yritysten järjestelmien suorituskykyyn. Tuloksien perusteella Stora Enson palkkakeskus tarjoaa kustannustehokkaan ja kilpailukykyisen ratkaisun, joka menestyy hyvin vertailussa muihin suomalaisiin yrityksiin.

The effect of pulp washing on bleaching efficiency

The main aim of this study was to inspect the influence of the ultrafiltration implementation on the washing and on bleaching efficiency. Four cases corresponding to four washing stages were observed: two with hardwood pulp and two with softwood pulp; each case had a reference and a trial experiment. The experiments with hardwood pulp were arranged in a manner to explore predominantly the possibility of bleaching performance improvement by applying for washing instead of untreated filtrate (reference case) the same treated one (trial case). Despite that the ultrafiltration reduced the COD of the wash filtrates allowing the decreasing of COD carry-over to the bleaching stage it didn’t affect the bleaching performance. Another set was used in the experiments with softwood pulp. It implied the ultrafiltration and recirculation of the filtrate to the same washing stage with the purpose to reduce the volumes and pollution of the bleaching effluents. In one case the negative result was obtained which was expressed by worse parameters of the pulp after bleaching. Another case showed the opportunity to replace hot water with the filtrate and reduce the fresh water consumption.

Environmental policy instruments concerning industrial end-use energy efficiency

Energy efficiency and saving energy are the main question marks when thinking of reducing carbon dioxide emissions or cutting costs. The objective of thesis is to evaluate policy instruments concerning end-use energy efficiency of heavy industry in European Union. These policy instruments may be divided in various ways, but in this thesis the division is to administrative, financial, informative and voluntary instruments. Administrative instruments introduced in this thesis are Directive on Integrated Pollution Prevention and Control, Directive on Energy End-use Efficiency and Energy Services, and Climate and Energy Package. Financial means include energy and emission taxation, EU Emission Trading Scheme and diverse support systems. Informative instruments consist of horizontal BAT Reference Document for Energy Efficiency, as well as substantial EU documents including Green Paper on Energy Efficiency, Action Plan for Energy Efficiency and An Energy Policy for Europe. And finally, voluntary instruments include environmental managements systems like ISO 14001 and EMAS, energy auditing and benchmarking. The efficiency of different policy instruments vary quite a lot. Informative instruments lack the commitment from industry and are thus almost ineffective, contrary to EU Emission Trading Scheme, which is said to be the solution to climate problems. The efficiency of administrative means can be placed between those mentioned and voluntary instruments are still quite fresh to be examined fruitfully. However, each instrument has their potential and challenges. Cases from corporate world strengthen the results from theoretical part. Cases were written mainly on the basis of interviews. The interviewees praised the energy efficiency contract of Finnish industry, but the EU ETS takes the leading role of policy instruments. However, for industry the reductions do not come easily.

Development of beam and plate finite elements based on the absolute nodal coordinate formulation

The focus of this dissertation is to develop finite elements based on the absolute nodal coordinate formulation. The absolute nodal coordinate formulation is a nonlinear finite element formulation, which is introduced for special requirements in the field of flexible multibody dynamics. In this formulation, a special definition for the rotation of elements is employed to ensure the formulation will not suffer from singularities due to large rotations. The absolute nodal coordinate formulation can be used for analyzing the dynamics of beam, plate and shell type structures. The improvements of the formulation are mainly concentrated towards the description of transverse shear deformation. Additionally, the formulation is verified by using conventional iso-parametric solid finite element and geometrically exact beam theory. Previous claims about especially high eigenfrequencies are studied by introducing beam elements based on the absolute nodal coordinate formulation in the framework of the large rotation vector approach. Additionally, the same high eigenfrequency problem is studied by using constraints for transverse deformation. It was determined that the improvements for shear deformation in the transverse direction lead to clear improvements in computational efficiency. This was especially true when comparative stress must be defined, for example when using elasto-plastic material. Furthermore, the developed plate element can be used to avoid certain numerical problems, such as shear and curvature lockings. In addition, it was shown that when compared to conventional solid elements, or elements based on nonlinear beam theory, elements based on the absolute nodal coordinate formulation do not lead to an especially stiff system for the equations of motion.

Improving and User Interface to E-Procurement Software Used in Asset Accounting and Investigating Effects to Efficiency

This diploma thesis has been done to international organization which takes care from the accounting actions of two major companies. In this organization are used three different purchasing tools which are used when new asset master data is wanted to input to SAP R/3- system. The aim of this thesis is to find out how much changing the user interface of one of these three e-procurement programs will affect to overall efficiency in asset accounting. As an addition will be introduced project framework which can be used in future projects and which help to avoid certain steps in the development process. At the moment data needs to be inputted manually with many useless mouse clicks and data needs to be searched from many various resources which slow down the process. Other organization has better tools at the moment than the myOrders system which is under investigation Research was started by exploring the main improvement areas. After this possible defects were traced. Suggested improvements were thought by exploring literature which has been written from usability design and research. Meanwhile also directional calculations from the benefits of the project were done alongside with the analysis of the possible risks and threats. After this NSN IT approved the changes which they thought was acceptable. The next step was to program them into tool and test them before releasing to production environment. The calculations were made also from implemented improvements and compared them to planned ones From whole project was made a framework which can be utilized also to other similar projects. The complete calculation was not possible because of time schedule of the project. Important observation in the project was that efficiency is not improved not only by changing the GUI but also improving processes without any programming. Feedback from end user should be also listened more in development process. End-user is after all the one who knows the best how the program should look like.

Induction Motor Drive Energy Efficiency - Simulation and Analysis

A coupled system simulator, based on analytical circuit equations and a finite element method (FEM) model of the motor has been developed and it is used to analyse a frequency-converterfed industrial squirrel-cage induction motor. Two control systems that emulate the behaviour of commercial direct-torque-controlled (DTC) and vector-controlled industrial frequency converters have been studied, implemented in the simulation software and verified by extensive laboratory tests. Numerous factors that affect the operation of a variable speed drive (VSD) and its energy efficiency have been investigated, and their significance in the simulation of the VSD results has been studied. The dependency of the frequency converter, induction motor and system losses on the switching frequency is investigated by simulations and measurements at different speeds for both the vector control and the DTC. Intensive laboratory measurements have been carried out to verify the simulation results.

Numerical Investigation of Flow Past a Circular Cylinder and in a Staggered Tube Bundle Using Various Turbulence Models

Transitional flow past a three-dimensional circular cylinder is a widely studied phenomenon since this problem is of interest with respect to many technical applications. In the present work, the numerical simulation of flow past a circular cylinder, performed by using a commercial CFD code (ANSYS Fluent 12.1) with large eddy simulation (LES) and RANS (κ - ε and Shear-Stress Transport (SST) κ - ω! model) approaches. The turbulent flow for ReD = 1000 & 3900 is simulated to investigate the force coefficient, Strouhal number, flow separation angle, pressure distribution on cylinder and the complex three dimensional vortex shedding of the cylinder wake region. The numerical results extracted from these simulations have good agreement with the experimental data (Zdravkovich, 1997). Moreover, grid refinement and time-step influence have been examined. Numerical calculations of turbulent cross-flow in a staggered tube bundle continues to attract interest due to its importance in the engineering application as well as the fact that this complex flow represents a challenging problem for CFD. In the present work a time dependent simulation using κ – ε, κ - ω! and SST models are performed in two dimensional for a subcritical flow through a staggered tube bundle. The predicted turbulence statistics (mean and r.m.s velocities) have good agreement with the experimental data (S. Balabani, 1996). Turbulent quantities such as turbulent kinetic energy and dissipation rate are predicted using RANS models and compared with each other. The sensitivity of grid and time-step size have been analyzed. Model constants sensitivity study have been carried out by adopting κ – ε model. It has been observed that model constants are very sensitive to turbulence statistics and turbulent quantities.

Efficiency of the ISM Code in Finnish Shipping Companies

Due to increasing waterborne transportation in the Gulf of Finland, the risk of a hazardous accident increases and therefore manifold preventive actions are needed. As a main legislative authority in the maritime community, The International Maritime Organization (IMO) has set down plenary laws and recommendations which are e.g., utilised in the safe operations in ships and pollution prevention. One of these compulsory requirements, the ISM Code, requires proactive attitude both from the top management and operational workers in the shipping companies. In this study, a crosssectional approach was taken to analyse whether the ISM Code has actively enhanced maritime safety in the Gulf of Finland. The analysis included; 1) performance of the ISM Code in Finnish shipping companies, 2) statistical measurements of maritime safety, 3) influence of corporate top management to the safety culture and 4) comparing safety management practices in shipping companies and port operations of Finnish maritime and port authorities. The main results found were that maritime safety culture has developed in the right direction after the launch of the ISM Code in the 1990´s. However, this study does not exclusively prove that the improvements are the consequence of the ISM Code. Accident prone ships can be recognized due to their behaviour and there is a lesson to learn from the safety culture of some high standard safety disciplines such as, air traffic. In addition, the reporting of accidents and nearmisses should be more widely used in shipping industry. In conclusion, there is still much to be improved in the maritime safety culture of the Finnish Shipping industry, e.g., a “no blame culture” needs to be adopted.