The society today lives on the philosophy of ‘take-make-use-dispose.’ In the long run, this is not sustainable as the natural resources and the waste carrying capacity of the earth are limited. Therefore, it is essential to reduce dependency on the natural resources by decoupling the growth from the consumption. In this venture, both the society and the manufacturing industry have a vital role to play. The society needs to shift towards Circular Economy that rests upon the philosophy of ‘take-make-use-reuse’ and the manufacturing industry has to be a major stakeholder in this shift. Despite being proven to be both economically and environmentally beneficial, successful examples of circular systems are few today. This is primarily due to two reasons; firstly, there is a lack of systemic and systematic approach to guide industries and secondly, there is a lack of analysis methods and tools that are capable of assessing different aspects of circular manufacturing systems. Taking on to these challenges, the objective of this research is to bring forward a framework with methods and decision support tools that are essential to implement circular manufacturing systems. The initial conceptual framework with the systemic approach is developed based on extensive review and analysis of research, which is further adapted for industrial implementation. Systematic analysis methods, decision support and implementation tools are developed to facilitate this adaptation. This development has been supported by four cases from diverse manufacturing sectors. Behind each decision support tool, there are analysis methods built upon mainly system dynamics principles. These tools are based on simulation platforms called Stella and Anylogic. Among other things, these tools are capable of assessing the performance of closed-loop supply chains, consequences of resource scarcity, potential gains from resource conservation and overall economic and environmental performance of circular manufacturing systems.

Purpose

The question of resource scarcity and emerging pressure of environmental legislations has brought a new challenge for the manufacturing industry. On the one hand, there is a huge population that demands a large quantity of commodities; on the other hand, these demands have to be met by minimum resources and pollution. Resource conservative manufacturing (ResCoM) is a proposed holistic concept to manage these challenges. The successful implementation of this concept requires cross functional collaboration among relevant fields, and among them, closed loop supply chain is an essential domain. The paper aims to highlight some misconceptions concerning the closed loop supply chain, to discuss different challenges, and in addition, to show how the proposed concept deals with those challenges through analysis of key performance indicators (KPI).

Methods

The work presented in this paper is mainly based on the literature review. The analysis of performance of the closed loop supply chain is done using system dynamics, and the Stella software has been used to do the simulation. Findings The results of the simulation depict that in ResCoM; the performance of the closed loop supply chain is much enhanced in terms of supply, demand, and other uncertainties involved. The results may particularly be interesting for industries involved in remanufacturing, researchers in the field of closed loop supply chain, and other relevant areas. Originality The paper presented a novel research concept called ResCoM which is supported by system dynamics models of the closed loop supply chain to demonstrate the behavior of KPI in the closed loop supply chain.

Anticipated scarcity of natural resources and concern for the sustainable development forcing manufacturing industries to emphasise on conservation of resources on one hand. On the other hand high competition in the manufacturing industry is forcing companies to look for innovative value propositions. Service based business models are emerging business solutions that fulfil the functional needs of customers. Such business approach demands extensive and sophisticated information collection, sharing and management systems. However, there are evidences of knowledge gap when it comes to defining information requirements, information management and sharing systems needed to adopt such business models. The objective of this paper is to provide an overview of research done in the area of service based business models in terms of information management and communication systems. The paper also includes result of two case studies done in two different manufacturing companies with the purposes to understand information requirements to adopt service based business models.

The question of resource scarcity and emerging pressure of environmentallegislations have put the manufacturing industry with a new challenge. On theone side, there is a huge population that demands a large quantity ofcommodities, on the other side, these demands have to be met by minimumresources and with permissible pollution that the earth’s ecosystem can handle.In this situation, technologic breakthrough that can offer alternative resourceshas become essential. Unfortunately, breakthroughs do not follow any rule ofthumb and while waiting for a miracle, the manufacturing industry has to findways to conserve resources. Within this research the anatomy of a large body ofknowledge has been performed to find the best available practices for resourceconservation. Critical review of the research revealed that none of the availablesolutions are compatible with the level of resource conservation desired by themanufacturing industry or by society. It has also been discovered that a largegap exists between the solutions perceived by the scientists and theapplicability of those solutions. Through careful evaluation of the state-of-theart,the research presented in this thesis introduced a solution of maximizingresource conservation i.e., material, energy and value added, as used inmanufacturing. The solutions emerged from the novel concept named asResource Conservative Manufacturing, which is built upon the concept ofMultiple Lifecycle of product. Unlike other research work, the researchdocumented in this thesis started with the identification of the problem andfrom which a ‘wish to do’ list was drawn. The seriousness of the problem andpotential of adopting the proposed concept has been justified with concreteinformation. A great number of arguments have been presented to show theexisting gaps in the research and from that, a set of solutions to conserveresources has been proposed. Finally, one of the prime hypotheses concerningclosed loop supply chain has been validated through the system dynamicsmodeling and simulation.

To ensure multiple-lifecycle of products through remanufacturing intervention requires a well-functioning closed-loop supply network. Generally, the unpredictability of quantity, timing and quality (physical/functional) of the returned products and demand fluctuation of the remanufactured products are the main sources of uncertainty of closed-loop supply network. To some extent, efficient recollection strategies and separate distribution channels for remanufactured products can minimize the uncertainty. Nevertheless, efficient recollection does not necessarily close the loop if the recovered products do not enter into the main stream of the supply network. Beside, products that are distributed through separate channels create an open loop. Thus, the problem of uncertainty remains unsolved. The aim of this paper is to propose solutions to minimize the uncertainty involved in designing a well-functioning closed-loop supply network using the system dynamics principle and tool.

The main drivers for adopting product multiple lifecycles are to gain ecological and economic advantages. However, in most of the cases it is not straight forward to estimate the potential ecological and economic gain that may result from adopting product multiple lifecycles. Even though many researchers have concluded that product multiple lifecycles result in gain, there are examples which indicate that the gain is often marginal or even none in many cases. The purpose of this research is to develop system dynamics models that can assist decision makers in assessing and analysing the potential gain of product multiple lifecycles considering the dynamics of material scarcity. The foundation of the research presented in this paper is laid based on literature review. System dynamics principles have been used for modelling and simulations have been done on Stella iThink platform. The data used in the models have been extracted from different reports published by World Steel Association and U.S. Geological Survey. Some of the data have been assumed based on expert estimation. The data on iron ore reserves, iron and steel productions and consumptions have been used in the models. This research presents the first system dynamics model for decision making in product multiple lifecycles which takes into consideration the dynamics of material scarcity. Physical unavailability and price of material are the two main factors that would drive product multiple lifecycles approach and more sustainable decisions can be made if it is done by taking holistic system approach over longer time horizon. For an enterprise it is perhaps not attractive to conserve a particular type of material through product multiple lifecycles approach which is naturally abundant but extremely important if the material becomes critical. An enterprise could through engineering, proper business model and marketing may increase the share of multiple lifecycle products which eventually would help the enterprise to reduce its dependency on critical materials.

The transition towards a circular economy has become important. Manufacturing industry being a major stakeholder in this transition has started exploring the potential of this transition and challenges in implementation. Ambitious companies such as Gorenje d.d. has taken the circular economy transition seriously and aims to become a pioneer in implementing circular manufacturing systems. One vital step in this transition is the business model shift from the linear (sales model) to a circular model such as 'product as a service'. This brings new challenges to Original Equipment Manufacturers (OEMs) that have never been experienced in their conventional businesses. One of the challenges is to establish an information communication and technology (ICT) infrastructure that enables information management and sharing as well as establishes a real-time communication between relevant stakeholders. Outlining such an ICT infrastructure is the objective of this paper.

Manufacturing companies are striving to remain competitive in the market and maintain their economic growth and productivity. Uncertainties regarding the changes in product demand, workpiece material, product design, and technological advancement, have imposed pressure on manufacturing systems. Market uncertainties force manufacturing companies to be flexible and responsive in producing different parts, by adapting the existing system without the need for a substantial investment. The market is characterized by time variations in product quantities and varieties while manufacturing systems remain inherently fixed. To sustain competitive manufacturing, a company has to adopt to new production requirements and be responsive to market changes quickly. Conscious decisions have to be made for a system to respond to market fluctuations. In order to respond to the dynamic changes, there is a need for developing methodologies that analyse, evaluate and control performance of manufacturing system at the system and/or process levels.

The primary focus of the thesis is to develop a novel generic framework for modelling and controlling manufacturing systems intending for improvement of the performance of manufacturing and make companies more competitive. The framework incorporates the complex interrelations between the process and system parameters, i.e., the dynamics of the system. Thus, provides a quantitative and qualitative analysis for performance evaluation and for optimizing performance of manufacturing system. The generic framework can further be adapted for studying specific manufacturing systems in discrete manufacturing. Three case studies are presented. The case studies are performed in an automotive company where the effect of various levels of control is investigated in manufacturing systems configured as transfer line or as a flexible manufacturing system.

Two aspects of the dynamic nature of manufacturing system are investigated in this thesis: (1) The engineering nature of the system, i.e., the selection of appropriate process parameters to manufacture a product according to the design specification, and (2) The business nature of the system, i.e., the selection of system parameters with respect to the way the product is manufactured. At the process level, the parameters are controlled within the process capability limits to adapt to the changes of the system parameters in response to the market dynamics. At the system level, operational parameters are controlled to satisfy performance criteria.

A case study for resource use analysis during primary processes has also been investigated and presented. The critical operations and the operations that have the highest energy consumptions and the potential for energy savings have been identified.

The methodology developed for analysing the performance of the dynamic manufacturing system is based on a system dynamics modelling approach. Results obtained from different modelling approaches are presented and compared based on the selected performance metrics.

This paper will introduce a novel methodology for the performance evaluation of machining strategies of engine block manufacturing. The manufacturing of engine components is vital to the automotive and vehicle manufacturing industries. Machining is critical processes in the production of these parts. To survive and excel in the competitive manufacturing environment, companies need to improve as well as update their machining processes and evaluate the performance of their machining lines. Moreover, the lines and processes have to be robust in handling different sources of variation over time that include such examples as demand fluctuations, work-piece materials or even any changes in design specifications. A system dynamics modelling and simulation approach has been deployed to develop a methodology that captures how machining system parameters from the machining process are interacted with each other, how these connections drive performance and how new targets affect process and machine tool parameters through time. The developed model could provide an insight of how to select the crucial machining system parameters and to identify the effect of those parameters on the output of the system. In response to such an analysis, this paper provides (offers) a framework to examine machining strategies and has presented model that is useful as a decision support system for the evaluation and selection of machining strategies. Here a system dynamics methodology for modelling is applied to the milling operation and the model is based on an actual case study from the engine-block manufacturing industry.

Our life is strongly linked with the usage of natural resources. Energy is a necessity in everyday life and is often generated using non-renewable natural resources which are finite. Energy consumption in manufacturing industry is increasing and the way it is consumed is not sustainable. There is great concern about minimizing consumption of energy in manufacturing industry to sustain the natural carrying capacity of the ecosystem. This is one of the challenges in today’s industrial world.In this paper two case studies have been carried out in crankshaft machining and cylinder head casting processes. The outcome of this research enables the company to identify potential avenues to optimize energy usage and offers a decision support tool.

Our life is strongly linked with the usage of natural resources. With increase in world population and welfare there is an increasing global demand for raw material. Energy is a necessity in everyday life and is often generated using non-renewable natural resources which are finite. Manufacturing is one of the largest energy and material resource consumers. There is great concern about minimising consumption of energy in manufacturing industry to sustain the natural carrying capacity of the ecosystem. This is one of the challenges in today’s industrial world. The paper presents the application of system dynamics theory for modelling and simulation of complex manufacturing processes. The simulations help to understand the intricate nature of the interrelation of process parameter and to make sound decision about minimising the energy losses. Two case studies are presented, one in cylinder head casting processes and the other in crankshaft machining. The developed models provide an insight into how to select critical operations and to identify the effect of various parameters on the energy consumption. Also, the models help to understand how changes of parameters over time affect the behaviour of energy changes. The outcome of this research enables the company to identify potential avenues to minimise energy usage and offers a decision support tool.

The worldwide competitive economy, the increase in sustainable issue and investment of new production line is demanding companies to choose the right machine from the available ones. An improper selection can negatively affect the overall performance of the manufacturing system like productivity, quality, cost and company’s responsive manufacturing capabilities. Thus, selecting the right machine is desirable and substantial for the company to sustain competitive in the market. The ultimate objective of this paper is to formulate a framework for machining strategy and also provide methodology for selecting machine tool from two special purpose machine tools in consideration of interaction of attributes. A decision support system for the selection of machine tool is developed. It evaluates the performance of the machining process and enhances the manufacturer (decision maker) to select the machine with respect to the performance and the pre-chosen criteria. Case study was conducted in a manufacturing company. A system dynamics modelling and simulation techniques is demonstrated towards efficient selection of machine tool that satisfy the future requirement of engine-block production.

To be competitive in a manufacturing environment by providing optimal performance in terms of cost-effectiveness and swiftness of system changes, there is a need for flexible production systems based on a well-defined strategy. Companies are steadily looking for methodology to evaluate, improve and update the performance of manufacturing systems for processing operations. Implementation of an adequate strategy for these systems’ flexibility requires a deep understanding of the intricate interactions between the machining process parameters and the manufacturing system’s operational parameters. This paper proposes a framework/generic model for one of the most common metal cuttingoperations—the boring process of an engine block machining system. A system dynamics modelling approach is presented for modelling the structure of machining system parameters of the boring process, key performance parameters and their intrinsic relationships. The model is based on a case study performed in a company manufacturing engine blocks for heavy vehicles. The approach could allow for performance evaluation of an engine block manufacturing system condition. The presented model enables a basis for other similar processes and industries producing discrete parts.

The machining operations that shape a metal component produce a raised edge or small pieces of material remaining attached to a work piece called burrs and sharp edges. The deburring process is intended to remove these imperfections and produce specific edge profiles.

Burr formation during machining operations is one of the most significant problems encountered by industrial companies in component manufacturing. Remaining burrs after machining pose a severe risk for component breakdowns, if the burrs get loose. All work piece edges must therefore be completely defect-free.

In the machining industry manual methods are commonly employed for burr removal. Fully automating deburring operations present a major challenge. Furthermore, removal of internal burrs of various sizes and shapes from parts sometimes becomes an extremely difficult task which causes high cost for labor, time losses, and health and safety risks.

Increasingly, manufacturers are expected to deliver burr-free parts to their customer. Sandvik Coromant, Scania and Volvo Cars are three of these manufacturers, and these three companies have agreed to contribute to this thesis.

Sandvik Coromant AB is part of the global enterprise Sandvik Group AB, and is world- leading in providing and developing cutting tools for the metal working industry. The company operates in over 60 countries worldwide and its main production plant is located in Gimo, Sweden [www.sandvik.com].

Scania is a global automotive industry manufacturer of commercial vehicles—specifically heavy trucks and buses. It also manufactures diesel engines for motive power of heavy vehicles, marine, and general industrial applications. Scania was founded in 1891 in Södertälje, Sweden. Today, Scania has ten production facilities worldwide [www.scania.com].

Volvo Car Corporation is an automobile manufacturer founded in 1927, in Gothenburg, Sweden. Volvo Cars has approximately 2,300 local dealers and around 100 national sales companies worldwide. Volvo Car Engine is a part of Volvo Cars. Volvo Car Engine produces engines and other components for other units, and it is headquartered in Skövde, Sweden [www.volvocars.com].

All of the companies above have problems in burr minimizing and removing strategy in machining and deburring operations to achieve quality assurance. Therefore, to choose a deburring system, and to reveal the results of deburring operations, it is necessary to be able to inspect/measure burrs. But, unfortunately, most industrial companies today lack the specialized systems to measure the presence of burrs, which adversely affect the overall deburring process. In this thesis, different types and sizes of work pieces have been taken directly from the production to measure burrs, and conduct experiments on them.

The thesis focuses on three areas:

• A survey of the current deburring problems, including burr classification and measurement, current minimization strategies of burr formation, and current deburring methods.
• Experiments on new and improved deburring methods, including deburring tools (e.g. drilling deburring tools, countersink tools, grinding tools and alumina fiber brushes), water-jet deburring (multi-nozzle rotary lance jets, pure and abrasive single rotary nozzle water jets).
• A selection matrix as a thesis conclusion which relates these methods to criteria of deburring processes, such as process performance, industrial applications, quality assurance, safety and environment, costs, etc. This matrix can be a basis for a more detailed selection/decision matrix in the future.

Increasing demands for high quality and high performance gear manufacturing are reflected in a need for a model based investigation of gear hobbing process. This paper presents the development of a system for online measurement of actual cutting force components during gear hobbing. Although there are a large number of well developed cutting force measuring systems for different machining operations available in the market, it is difficult to find a system tailored to the requirements of a gear hobbing process. Hence, a fixture containing piezoelectric dynamometer and telemetry device is developed. The fixture is designed taking the real machining circumstances into consideration. The telemetry system enables wireless measurement of cutting force while machining. Multiphysics finite element analysis and Artificial Neural Network (ANN) are used as tools for modeling, simulation, and calibration of the developed system. Final stage of this work includes conducting hobbing experiments to validate both the model and the force measurement system.

Comprehensive knowledge and information about the static and dynamic behaviour of machine tools, cutting processes and their interaction is essential for machining system design, simulation, control and robust operation in safe conditions. The very complex system of a machine tool, fixture and cutting tools during the machining of a part is almost impossible to model analytically with sufficient accuracy. In combination with increasing demands for precision and efficiency in machining call for new control strategies for machining systems. These strategies need to be based on the identification of the static and dynamic stability under both the operational and off-operational conditions. To achieve this it is necessary to monitor and analyze the real system at the factory floor in full production. Design information and operational data can then be linked together to make a realistic digital model of a given machining system. Information from such a model can then be used as input in machining simulation software to find the root causes of instability.

The work presented in this thesis deals with the static and dynamic capability of machining systems. The main focus is on the operational stability of the machining system and structural behaviour of only the machine tool, as well.

When the accuracy of a machining system is measured by traditional techniques, effects from neither the static stiffness nor the cutting process are taken into account. This limits the applicability of these techniques for realistic evaluation of a machining system’s accuracy. The research presented in this thesis takes a different approach by introducing the concept of operational dynamic parameters. The concept of operational dynamic parameters entails an interaction between the structural elements of the machining systems and the process parameters. According to this concept, the absolute criterion of damping is used to evaluate the dynamic behaviour of a machining system. In contrast to the traditional theory, this methodology allows to determine the machining system's dynamic stability, in real time under operating conditions. This framework also includes an evaluation of the static deformations of a machine tool.  In this context, a novel concept of elastically linked system is introduced to account for the representation of the cutting force trough an elastic link that closes the force loop. In addition to the elastic link which behaves as a static element, a dynamic non-contact link has been introduced. The purpose is to study the non-linear effects introduced by variations of contact conditions in joints due to rotational speed.

The increasing demands for precision and efficiency in machining call for new control strategies for machining systems based on the identification of static and dynamic characteristics under operational conditions. By considering the machining system as a closed-loop system consisting of a machine tool structure and a machining process, the join system characteristics can be analyzed. The capability of a machining system is mainly determined by its static and dynamic stiffness.

The goal of this thesis is to introduce some concepts and methods regarding the identification of machining system stability. Two methods are discussed, one for the static behaviour analysis of a machine tool, and one for dynamic stability of a machining system. Preliminary results are indicating unambiguous identification of capabilities of machining systems static and dynamic characteristics.

The static behaviour of a machine tool is evaluated by use of a loaded double ball bar (LDBB) device. The device reproduces the real interaction between the join system, the machine tool elastic structure and the cutting process. This load is not equivalent to real cutting forces, but it does have a similar effect on the structure. This has been investigated both trough simulation and experimental work.

It is possible to capture the process – ­machine interaction in a machining system by use of the model-based identification approach. The identification approach takes into consideration this interaction and can therefore be used to characterize the machining system under operational conditions. The approach provides realistic prerequisites for in-process machining system testing. The model parameters can be further employed for control and optimization of the cutting process. Using different classification schemes, the model-based identification method is promising for the detection of instability.

Furthermore, it is the author’s belief that a model-based stability analysis approach is needed to exploit the full potential of a model driven parts manufacturing approach.

In today’s highly competitive environment there is a need for fast and accurate methods to assess the capability of manufacturing units. The traditional estimation of the dynamic properties of machine tools is usually time consuming and assumes time-invariant properties. This paper introduces a method for analyzing machine tool structure dynamic properties by recursive estimation of modal and operational parameters. A contact-less excitation system and a specially designed tool were employed to enable spindle speed sweep. The primary contribution of this paper lies within the formulation and implementation of recursive parametric models for tracking the time-varying dynamic properties of a machine tool structure.

The spindle system is a critical part of a machine tool structure and its dynamic properties are important for the performance of the whole machining system. Currently the only way to extract the dynamic properties of a given structure is via experimental modal analysis. This approach, however, can only be employed on idle systems and is performed with the assumption that the dynamics of a system are independent of rotational speed. The latter assumption cannot be applied to spindle systems. This paper introduces a novel testing system for analysing machine tool spindles dynamic properties, consisting of real-time recursive estimation of modal and operational dynamic parameters, employed alongside a contactless excitation and response system. The presented approach allows analysing the spindle system condition and dynamic properties not only at discrete rotational speed intervals but also during continuous sweep of rotational speed.

The paper introduces the concept of Elastically Linked Systems (ELS) to directly relate the machine tool positional and static accuracy to the machined part’s geometric errors and form deviation. Practical implementation of the ELS concept resulted in a novel test equipment, Loaded Double Ball Bar (LDBB) which is a precision mechatronic device with variable load. The test method based on the device is able to reveal machine tool characteristics not obtainable with existing methods as for instance the variation of stiffness in the entire working space. The LDBB is used to experimentally evaluate the stiffness and the corresponding accuracy of five machine tools.

The key concept of the identification procedure in this paper is to find a feature of the measured random response (sound pressure) that can be used to discriminate between stable and unstable process-machine interaction (PMI) in milling. The dynamic condition of the machining system is represented by the operational dynamic parameters (ODP), which refer to the contribution of the structural vibration modes and process vibration modes resulting during machining system operation. It is shown that the sound pressure level acquired by a microphone, located in the machine’s working area, is able to follow rapid changes in the process dynamics and therefore may be used as input in the recursive estimation scheme. The primary contribution of this paper lies within the formulation and implementation of recursive parametric models for the study of the real-time dynamics of a face milling operation PMI. A comparison between the experimental, simulated, and identified results is outlined.

The aim of this paper is to introduce a novel methodology, based on a finite element (FE) computation engine for validating of real-time identification schemes applied in machining. FE modelling of the milling process has the purpose of being accountable for a thorough validation of the parametric identification approach, and of providing a good physical insight into the phenomena investigated. The system considered here has a lower number of degree-of-freedoms which permits a thorough analysis. However, when taking into account the system’s nonlinear and time-varying nature, it is clear that the results are far from being trivial. Therefore, the analysis of the milling process, taking into account nonlinearities restricting the growth of response amplitudes in the case of chatter-type instability, provides some intrinsic information of the basic features on the system that might be of both fundamental interest and practical use.

This paper presents a novel test device for the evaluation of the accuracy of machine tools. The design concept is similar to a double ball bar (DBB) with the difference that an adjustable load generated by the device can be applied between spindle nose and machine tool table. The device, called Loaded Double Ball Bar (LDBB), can be used either as an ordinary double ball bar system with no load applied to the structure, or with a predefined load applied to the structure. The load that is generated by the LDBB is generally not equivalent to real cutting forces. However, from the static deflection point of view the effect of the load on the machine tool structure has similar impact on the static behaviour of the system. For instance, the load can in some cases eliminate existing play in ball screws, plays that under normal machining condition will be eliminated by the effect of cutting forces on the structure. With the help of this test device, not only can the identifiable errors by an ordinary DBB be evaluated but also machine tool elastic deflection in different directions. It is also possible to track different error patterns to the applied load.

The aim of this paper is to introduce a novel methodology, based on a finite element (FE) computation engine for simulation of process machine interaction occurring in machining systems. FE modelling of the milling process has the purpose of being accountable for a thorough validation of the parametric identification approach, and of providing a good physical insight into the phenomena investigated. The system considered here has a lower number of degree-of-freedoms which permits a thorough analysis. However, when taking into account the system’s nonlinear and time-varying nature, it is apparent that the results are far from being trivial. Therefore, the analysis of the milling process, taking into account nonlinearities restricting the growth of response amplitudes in the case of chatter-type instability, provides some intrinsic information of the basic features on the system that might be of both fundamental interest and practical use.

This paper presents a novel test concept for the evaluation of the accuracy of NC machine tools. The evaluation of machine tools deformations is performed by help of a device similar to the double ball bar (DBB) with the difference that an adjustable load generated by the device can be applied between spindle nose and machine tool table. This load eliminates the play existing in machine tool joints, thus reproducing the testing conditions that exist during machining. Collected data are used to plot diagrams displaying characteristic aspects of achine tool performance and a number of key figures such as static stiffness may be etermined. The data can also be used for trend analysis; to predict any accuracy deviations, and further to conduct preventive maintenance instead of emergency calls. The determined static behaviour could also be used to improve digital models for process simulations and compensation of errors that are caused by deflection.

Granted by the EU Programme Leonardo da Vinci, a two-year pilot project, EPRODEC (European Production Engineering Certification) has been started. The aim of EPRODEC is to provide an appropriate “European Label” to the graduates of the accredited Production Engineering (PE) programme. The objective is to develop an accreditation system and organization that will implement the certification process for education and training within the field of Production Engineering all over Europe. Creating a unified accreditation system will make it easier to compare qualifications and skills. The paper presents some of the ideas behind EPRODEC and the first results.

The Swedish truck industry is forced to find new material solutions to achieve lighter engines with increased strength. Customers and new environmental regulations demand both higher specific power and more environmentally friendly trucks, and this places a rising pressure on the manufactures. This demand could be met by increasing the peak pressure in the cylinders. Consequently, a more efficient combustion is obtained and the exhaust lowered. This however exposes the engine to higher loads and material physical properties must therefore be enhanced.

Today, alloyed gray iron is the predominantly used engine material. This material cannot meet the requirements of tomorrow’s engines. Compacted Graphite Iron has good potential to be the replacement; it opens new design opportunities with its superior strength, which can lead to smaller, more efficient engines and additional power. The question is: how will manufacturing be affected?

The main goal of this thesis is to identify and investigate the main factors’ effect and their individual contributions on CGI machining.  When the relationship between the fundamental features; machinability, material microstructure, and material physical properties, are revealed, then the CGI material can be optimized, both regarding the manufacturing process and design requirements. The basic understanding is developed mainly through experimental analysis. No attempt has been made to optimize the material to be used as engine material in this thesis.

The thesis demonstrates the importance of having good casting process control. It also illustrates the microstructural properties’ effects on CGI machinability, and what new aspects of machining must be taken into account, compared to gray iron.

Due to environmental regulations, the industry uses both new and recycled material for the casting of new components. In the heavy truck industry, great effort is put into the purchasing of “good quality” recycled/scrap material to be used for casting CGI (compacted graphite iron) cylinder blocks and cylinder heads. Scrap material with a large concentration of carbide promoting elements reduces the machinability drastically due to carbides. The effect of carbide promoting elements on CGI machinability needs to be investigated in order to produce high quality engine components in an economically satisfactory way. This study presents the effect of the carbide promoting elements of chromium, manganese and molybdenum on CGI material processing. 17 unique CGI materials with different material chemical composition were studied. Material testing, milling experiments and image analysis of microstructure were performed on all materials, mapping the process machine interaction. The results show that all carbide promoting elements, but especially chromium, reduce the tool life in CGI milling. The results also illustrate the interaction between concentration of carbide promoting elements, material strength and machinability.

Swedish truck industry is investigating the possibilityfor implementing the use of Compacted Graphite Iron (CGI) in theirheavy duty diesel engines. Compared to the alloyed gray iron usedtoday, CGI has superior mechanical properties but not as goodmachinability. Another issue that needs to be addressed whenimplementing CGI is the inhomogeneous microstructure when thecast component has different section thicknesses, as in cylinderblocks. Thinner sections results in finer pearlite, in the material, withhigher strength. Therefore an investigation on its influence onmachinability was needed. This paper focuses on the effect thatinterlamellar distance in pearlite has on CGI machinability andmaterial physical properties. The effect of pearlite content andnodularity is also examined. The results showed that interlamellardistance in pearlite did not have as large effect on the materialphysical properties or machinability as pearlite content. The paperalso shows the difficulties of obtaining a homogeneousmicrostructure in inhomogeneous workpieces.

The need for a flexible and versatile workforce that is constantly learning and upgrading its skills has led to a continual demand for courses in which employees are re-trained and updated on a lifelong basis. Students and workers now have to be prepared for a labour market in which they can be expected to change jobs many times, and they need to acquire appropriate skills that are transferable and portable across sectors, countries and cultures. This paper presents a new approach to unifying a European curriculum for production engineering. The paper discusses the background, developments, module structure, testing and ongoing work that is carried out in the European Production Engineering Certification project – a two year pilot project granted by the European Union Programme Leonardo da Vinci.

Strukturoptimering används ofta i produktutvecklingsprocessen i modern industri för att ta fram optimala konstruktioner med minsta möjliga materialåtgång för komponenten. Konventionella konstruktionsmetoder genererar vanligtvis överdimensionerade komponenter med överflödigt material och vikt. Detta ökar i sin tur livstidskostnaderna för maskiner både i termer av materialavfall och användning. Avhandlingen "Konstruktion av viktoptimerad gjuten ADI-komponent" behandlar omkonstruktionen av en komponent från en svetsad stålplåtstruktur till en gjutbar konstruktion med minskad tillverkningskostnad och vikt. Komponenten “Borrstöd” monterad i framkant av bommen på en ortdrivningsmaskin är omkonstruerad under detta arbete. Huvudsyftet med avhandlingen är ta fram en alternativ konstruktion med lägre vikt och som kan monteras på befintlig maskinlayout utan någon ändring i monteringsgränssnittet. Denna avhandling innehåller en detaljerad beskrivning av förfarandet för att uppnå viktminskningen av "borrstödet" och presenterar resultaten samt metodiken som baseras på både topologi- och parameter- optimering.

With advances in material technology, allowing, for instance, engines to withstand higher combustion pressure and consequently improving performance, comes challenges to productivity. These materials are, in fact, more difficult to machine with regards to tool wear and especially machine tool stability. Machining vibrations have historically been one of the major limitations to productivity and product quality and the cost of machining vibration for cylinder head manufacturing has been estimated at 0.35 euro per part.

The literature review shows that most of the research on cutting stability has been concentrating on the use of the stability limits diagram (SLD), addressing the limitations of this approach. On the other hand, research dedicated to development of machine tool components designed for chatter avoidance has been concentrating solely on one component at the time.

This thesis proposes therefore to extend the stability limits of the machining system by enhancing the structure’s damping capability via a unified concept based on the distribution of damping within the machining system exploiting the joints composing the machine tool structure. The design solution proposed is based on the enhancement of damping of joint through the exploitation of viscoelastic polymers’ damping properties consciously designed as High Damping Interfaces (HDI).

The tool-turret joint and the turret-lathe joint have been analysed. The computational models for dimensioning the HDI’s within these joints are presented in the thesis and validated by the experiments. The models offer the possibility of consciously design damping in the machining system structure and balance it with regards to the needed stiffness.

These models and the experimental results demonstrate that the approach of enhancing joint damping is viable and effective. The unified concept of the full chain of redesigned components enables the generation of the lowest surface roughness over the whole range of tested cutting parameters. The improved machining system is not affected by instability at any of the tested cutting parameters and offers an outstanding surface quality.

The major scientific contribution of this thesis is therefore represented by the proposed unified concept for designing damping in a machining system alongside the models for computation and optimisation of the HDIs.

From the industrial application point of view, the presented approach allows the end user to select the most suitable parameters in terms of productivity as the enhanced machine tool system becomes less sensitive to stability issues provoked by difficult-to-machine materials or fluctuations of the work material properties that may occur in ordinary production processes.

This paper introduces a novel design for boring bar with enhanced damping capability. The principle followed in thedesign phase was to enhance the damping capability minimizing theloss in static stiffness through implementation of composite materialinterfaces. The newly designed tool has been compared to a conventional tool. The evaluation criteria were the dynamic characteristics, frequency and damping ratio, of the machiningsystem, as well as the surface roughness of the machined workpieces.The use of composite material in the design of damped tool has been demonstrated effective. Furthermore, the autoregressive moving average (ARMA) models presented in this paper take in to consideration the interaction between the elastic structure of themachine tool and the cutting process and can therefore be used to characterize the machining system in operational conditions.

Ultraprecision (UP) components have become common in everyday life products such as mobile phones or compact high resolution digital cameras. Thus the need of producing such components with high accuracy and low production cost. UP machine tools are capable of extremely high accuracy in tool positioning but still today the workpiece is positioned by hand, hence the high production cost of UP components. A fully automated chain of production has been developed within the EU-IP project “Production 4 micro”. This paper describes the active alignment chuck for workholding in UP machining. The chuck has been provided with a high damping interface (HDI) and to evaluate its efficiency the chuck has undergone an experimental modal analysis (EMA) as well as machining tests. The chosen operation was grooving by fly cutting using a diamond tool. The EMA showed that the HDI was effective for those modes where there was relative displacement between one side and the other of the HDI. This result was confirmed by the machining tests as well. The HDI resulted being effective in damping high frequency modes (around 4 – 5 kHz), hence one expected benefit would be a longer tool life.

With advances in material technology come challenges to productivity. New materials are, in fact, more difficult to machine with regards to tool wear and especially machine tool stability. This paper proposes to extend the stability limits of the machining system by enhancing the structure’s damping capability. The aim of the research work presented here is to introduce a unified concept based on the distribution of damping within the machining system components exploiting the dynamic properties of the existing joints. To maintain a high level of static stiffness, it was chosen to adapt hydrostatic clamping systems to the tools. Damping is designed in the structure via high damping interfaces (HDI), intentionally introduced interfaces where the damping ratio is enhanced by introduction of viscoelastic polymer metal composites between the two metallic surfaces composing the interface. In this paper HDI are introduced at two joints, between tool and turret and between turret and lathe. The tests show that the designed-in damping is effective and allows extending the stability limits of the machining system. The implementation of designed-in damping allows the end user to select the most suitable parameters in terms of productivity avoiding the hassle of tuning the devices, having to acquire a deep knowledge in structural dynamics or having to use additional control systems. In addition to this, the enhanced machine tool system becomes less sensitive to stability issues provoked by difficult-to-machine materials or even fluctuations of the work material properties that might occur in everyday production processes.

Automotive industry is always struggling to comply with more and more restrictive emission regulations and the trend has been to employ engine materials that can allow higher combustion pressure and lighter design. Compacted Graphite Iron (CGI) is a class of materials that can allow this, but material and mechanical properties may largely vary within the given specification for CGI. Therefore there is a need for a fast and reliable method for classify CGI according to its properties. Impact Acoustic Testing (IAT) method of inspection measures the structural response of a part. Its volumetric approach tests the whole part providing objective and quantitative results. The aim of this paper is to demonstrate that it is possible to distinguish the test objects’ mechanical and material properties provided that geometrical dimensions are not varying. The results show the potential and limitations of this method in the given application.

Obtaining the first part correctly is of vital importance. One way of achieving this is to implement solutions with machine tool components that can enable higher removal rates with unchanged or even improved machining performance. A solution is presented in this paper where the principle followed has been to enhance the damping capability of critical structural components of the machine tool (boring bar and turret), minimizing the loss of stiffness. An analytical model of the damping treatment used is presented. The model has been verified by the experimental modal analysis and the machining tests. The introduction of damping in the machine tool structure has been proved to enable machining in stable conditions over a larger range of cutting parameters. The interaction between the cutting process and the machine structure is therefore revealed.

The precision of machining systems is ever increasing in order to keep up with components’ accuracy requirements. At the same time product variants areincreasing and order quantities are decreasing, which introduces high demands on the capability of machining systems. The machining system is an interaction between the machine tool structure, the process and the control system and is defined in terms of capability by the positional, static, dynamic and thermal accuracy. So far, the control of the machining system, in terms of static and dynamic stability is process based which is often translated into sub-optimum process parameters and therefore low productivity.This thesis proposes a new approach for control of the machining systemwhich is based on the capability to control the structural properties of themachine tool and as a result, controlling the outcome of the machining process.The control of the structural properties is realized by carefully designed Joint Interface Modules (JIMS). These modules allow for control of the stiffness and damping of the structure, as a result of tuning the contact conditions on the interface of the JIM; this is performed by control of the pre-load on the interface,by treatment of the interface with damping enhancing materials, or both. The thesis consists of a presentation of the motivation behind this work, the theoretical basis on which the proposed concept is based and a part describing the experimental investigations carried out. Two prototype JIMs, one for a milling process and one for a turning process were used in the experimental investigations that constitute the case studies for examining the validity of the proposed concept and demonstrating its applicability in a real production environment.

Vibration phenomena are a main consideration during the material removal operation, as it has prominent effects on the product quality, cutting tool life, and productivity of that machining operation. Within the context of machining performance, role of enhanced stiffness and damping on the dynamic behaviour of machining systems such as turning and milling is well established. In this experimental analysis, investigations have been conducted for identifying the natural characteristics and dynamic responses of a milling process with the application of a novel carbon based (CNx) nano-composite damping material. TheCNx material has been applied into the joint interface of a workholding device with adaptive dynamic stiffness. Prior investigations of this material, produced by theplasma enhanced chemical vapor (PECVD) process, showed inherent damping capacity via interfacial frictional losses of its micro-columnar structures. For thisstudy, natural characteristics of the workholding system have been characterized bythe modal impact testing method. Dynamic responses during the machining processhave been measured through the vibration acceleration signals. The ultimate objective of this study is to comprehend the potentiality of CNx coating material forimproving machining process performance by analyzing the frequency response functions and measured vibration signals of the investigated milling process with varying stiffness and damping levels.

A main consideration in the operation of machine tools is vibrations occurring during the cutting process.Whether they are forced vibrations or self-excited ones, they have pronounced effects on surface quality, tool lifeand material removal rate. This work is an experimental study of interactions between natural characteristics,control parameters and process parameters of a machining system designed with adaptive dynamic stiffness. Inorder to comprehend these interactions, the effect of changes in dynamic stiffness on the system’s response isexamined. The system under study consists of an end-milling tool, a steel workpiece and a work holding devicewith controllable stiffness. Natural dynamic characteristics of the system components are determined throughmodal impact testing. Then the behaviour of the whole machining system is examined under both high and lowcutting speed conditions by analysing vibration levels using acceleration signals acquired through a tri-axialsensor mounted on the workpiece. Cutting is performed in both directions of the horizontal plane of a CNCmilling machine. In both cases the results are presented for two extremes of stiffness and damping in the workholding device. The effect of control parameters on the system’s natural characteristics could be identifiedtogether with a relation between these parameters and the system’s response in high and low cutting speedconditions. The high-damping configuration reduces the vibration amplitudes significantly, while the increaseof pre-stress has a different effect depending on the cutting conditions.

Vibration control requires high dynamic stiffness in mechanical structures for a reliable performance under extreme conditions. Dynamic stiffness composes the parameters of stiffness (K) and damping (η) that are usually in a trade-off relationship. This thesis study aims to break the trade-off relationship.

After identifying the underlying mechanism of damping in composite materials and joint interfaces, this thesis studies the deposition technique and physical characteristics of nano-structured HDS (high dynamic stiffness) composite thick-layer coatings. The HDS composite were created by enlarging the internal grain boundary surface area through reduced grain size in nano scale (≤ 40 nm). The deposition process utilizes a PECVD (Plasma Enhanced Chemical Vapour Deposition) method combined with the HiPIMS (High Power Impulse Magnetron Sputtering) technology. The HDS composite exhibited significantly higher surface hardness and higher elastic modulus compared to Poly(methyl methacrylate) (PMMA), yet similar damping property. The HDS composites successfully realized vibration control of cutting tools while applied in their clamping interfaces.

Compression preload at essential joint interfaces was found to play a major role in stability of cutting processes and a method was provided for characterizing joint interface properties directly on assembled structures. The detailed analysis of a build-up structure showed that the vibrational mode energy is shifted by varying the joint interface’s compression preload. In a build-up structure, the location shift of vibration mode’s strain energy affects the dynamic responses together with the stiffness and damping properties of joint interfaces.

The thesis demonstrates that it is possible to achieve high stiffness and high damping simultaneously in materials and structures. Analysis of the vibrational strain energy distribution was found essential for the success of vibration control.

Vibration problems are still the major constraint in modern machining processes that seek higher material removal rate, shorter process time, longer tool life and better product quality. Depending on the process, the weaker structure element can be the tool/tool holder, workpiece/fixture or both. When the tool/tool holder is the main source of vibration, the stability limit is determined in most cases by the ratio of length-to-diameter. Regenerative chatter is the most significant dynamic phenomenon generated through the interaction between machine tool and machining process. As a rule of thumb, the ratio between the tool’s overhang length and the tool’s diameter shouldn’t exceed 4 to maintain a stable machining process while using a conventional machining tool. While a longer tool overhang is needed for specific machining operations, vibration damping solutions are required to ensure a stable machining process. Vibration damping solutions include both active and passive damping solutions. In the passive damping solutions, damping medium such as viscoelastic material is used to transform the vibration strain energy into heat and thereby reduce vibration amplitude. For a typical cantilever tool, the highest oscillation displacement is near the anti-node regions of a vibration mode and the highest oscillation strain energy is concentrated at the node of a vibration mode. Viscoelastic materials have been successfully applied in these regions to exhibit their damping property. The node region of the 1st bending mode is at the joint interfaces where the cantilever tools are clamped. In this thesis, the general method that can be used to measure and characterize the joint interface stiffness and damping properties is developed and improved, joint interfaces’ importance at optimizing the dynamic stiffness of the joint interface is studied, and a novel advancing material that is designed to possess both high young’s modulus and high damping property is introduced. In the joint interface characterization model, a method that can measure the joint interface’s stiffness and damping over the full frequency range with only the assembled structure is presented. With the influence of a joint interface’s normal pressure on its stiffness and damping, an optimized joint interface normal pressure is selected for delivering a stable machining process against chatter with a boring bar setting at 6.5 times overhang length to diameter ratio in an internal turning process. The novel advancing material utilizes the carbon nano particles mixed in a metal matrix, and it can deliver both high damping property and high elastic stiffness to the mechanical structure.

Multi-layered nanostructured Cu and Cu-CNx composites synthesized by plasma-enhanced chemical vapour deposition were applied in the clamping area of a milling tool to suppress regenerative tool chatter. Scanning electron microscopy analysis showed a multi-layered nanostructure with excellent conformality, i.e. coating is not only uniform on planar surfaces but also around corners of the substrate. Cu:CuCNx nanostructured multilayers with thicknesses of approximately 0.5:1.6 mu m were obtained. With a diameter of 20 mm, the milling tool performed slotting processes at an overhang length of 120 mm. Modal analysis showed that a coating, with a thickness of approximately 300 mu m, can add sufficient damping without losing stiffness of the tool, to increase the critical stability limit by 50% or 100% depending on cutting direction.

Machining dynamic stability has been enhanced through a damping coating based on a novel carbon-based nanocomposite material. The coating was synthesized using a plasma enhanced chemical vapor deposition method, and deposited on to the round-shank boring bar used for internal turning and tested during machining. Comparisons between an uncoated and a coated boring bar were carried out at 0.25 mm and 0.5 mm depth of cut using a five times length to diameter ratio overhang, which are typical conditions known to generate detrimental mechanical vibrations. From sound pressure measurement it was found that the measured absolute sound level during process could be reduced by about 90% when using the tool coated with damping layer. Surface roughness measurements of the processed workpiece showed decreased Ra values from approximately 3-6 mu m to less than 2 mu m (and in 50% of the cases < 1 mu m) when comparing an uncoated standard tool with its coated counterpart. Moreover, it was found that the addition of an anti-vibration coating did not adversely affect other tool properties, such as rigidity and modularity.