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.

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.

Vibration control has been and still remains a subject of primary importance in modern manufacturing industry. To be able to remove high volumes of material in shorter time as well as to be able to get the right quality of the parts at the first time are goals that many shops would like to achieve. Tooling systems, and especially cantilever tools, and cantilever structural units of machine tools are the least rigid components of machining systems and therefore the most prone to vibration. Boring tools are often encountered as rotating tools in machining centres or as stationary tools in internal turning. In this thesis the focus is on internal turning. Internal turning is widely known as a very delicate operation and it is often carried out with cutting parameters far from optimal, from a productivity point of view, due to limitations imposed by vibration. Another type of tooling system whose functionality is impaired by vibration is the parting-off tool. The design of damped parting-off tool is one of the focus of this thesis as well. Vibration control has the purpose to achieve an efficient energy dissipation of a vibrational system. Basically this is achieved by controlling the damping of the system. Since damping involves the conversion of energy associated with a vibration to other forms, there are several mechanisms to remove energy from a vibrating system. Typically these mechanisms are divided in two classes:

1. Mechanisms that convert mechanical energy to heat, i.e. passive damping.

2. Mechanisms that transport energy away from vibrating systems, i.e. active damping.

Both these techniques have been used during the years and both have been giving excellent results. The active vibration control mechanisms are more expensive and not suitable for machining due to the cables they necessitate that could interfere with the machining operation. This work proposes an original approach to vibration damping in machining systems, the objects of vibration dissipation being the structural components on the link between turret and cutting insert. The idea is to use composite materials to create damping interfaces between and within the different structural components. Different clamping system designs are being compared in order to see how these influence the performance of the machining system and different cutting inserts have been compared for machining hardened steel. The newly designed components have been going through both extensive off-line (modal analysis) and on-line dynamic testing (machining test) and the results show that the new tool holders used in combination with hydrostatic clamping system are the most optimal solution among the tested ones. The new design for the turret has been giving promising results and more can be achieved by bringing minor changes to it, these changes are being implemented at the time of writing this thesis.

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.

The objective of the research presented in this paper is to characterize the machinability of TOOLOX 44 during cutting with PALBIT inserts with focus on how different combinations of coatings and substrates influence the machining process in aspects such as tool life, cutting forces, temperature and chip forming process.

The foremost result is that TOOLOX is machinable and when the right tool is chosen high productivity can be achieved. Using the right insert, equipped with chipbreaker, should allow to machine this hardened steel even at higher cutting speeds than the ones used in this investigation.

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.

This paper investigates the function of metal working fluid (MWF) emulsions in automotive industries in Sweden and looks at how the negative environmental and health impact of their use can be reduced through means of monitoring and system design. Major input to this study has been collected from several of the large companies in Sweden, through a literature review, interviews, questionnaires, findings from workshops and comparisons with other countries. The mapping of this data was carried out, firstly by defining several concepts and terms related to MWFs in order to give an unambiguous terminology. The MWF system design, with its impact on economical, environmental and health and safety parameters, is then described more in detail. Finally, applied monitoring methodologies are reviewed and analysed in terms of common and best practices. Insights gained were formulated as general recommendations for designing a state-of-the-art sustainable MWF system. The article gives examples of how these recommendations translate into practical design features and requirements of monitoring, and maybe of interest for professionals and researchers working with machining technology, process fluid system design and control methodology.

An increasing number of Higher Education professionals have embraced the Constructivism theory in contrast with the traditional transmissive pedagogy approach where the focal figure is the teacher. Constructivists emphasizes that the learners acquire, or construct, knowledge through their own activities and previous knowledge. Teacher role is to set up an environment that can provide a good learning experience for the students. In view of this the alignment of the intended learning outcome (ILO) with the teaching and learning activity (TLA) and the assessment task (AT) of the course becomes an important requirement for good learning. The driver of the alignment is the educational goal verb (EGV) that represents the educational goal underling a specific intended learning outcome (ILO). This verb should be elicited by the course's TLA and be the base for the consequent AT. The convergence of constructivism with this concept generates the constructive alignment pedagogical paradigm. The CONALI ontology answers the requirement for a structured framework to describe the vast body of knowledge developed in such a field. The salient aspects of constructive alignment have been extracted and classified in a comprehensive taxonomy. The following description of the semantic relationships among the different classes resulted in the CONALI ontology. The chosen modelling language is OWL: this provides the possibility to describe in a computer understandable way a higher education courses to an unprecedented level of detail. OWL enables also the creation of a specific knowledge base by populating the model. The knowledge base can then be analysed and interrogated on many important issues concerning the alignment of the instantiated course. The CONALI ontology becomes an important tool to design and synthesize the related domain knowledge. This paper proves the usability of CONALI ontology as tool to represent the courses in an engineering program and evaluate the alignment of their activities. The specific instantiation is based on the Industrial Engineering program at KTH Royal Institute of Technology in Stockholm, Sweden.

This paper presents a study where acoustic imaging technology was employed for problem identification and high damping interfaces (HDI) were implemented in the machine tool structure to improve performance of process machine interaction, in bevel gear cutting, in terms of resistance to instability. Chatter marks at the gear root and tool fracturing represent a serious and widespread problem in the studied process. The acoustic image approach showed good agreement with modal analysis and also allowed to identify the chatter frequency. Once identified the problem, the paper also presents a novel approach for improving resistance to cutting instability by implementing HDI in the structure. The HDI consists of a viscoelastic composite material and is used to damp out the stick blade motion relative to the clamp block by transformation of vibratory energy, into heat. The primary contributions of this paper are the introduction of acoustic imaging for identification of chatter in gear cutting and employment of HDI for performance improvement for rotating tools.

Dynamic characteristics of machine tools and cutting tools have gained much attention from researchers and industry as it is one of the major factors limiting productivity due to excessive vibrations such as chatter during the cutting process. Numerous factors have to be taken into consideration when selecting material of the cutter body. This paper presents a comparison between two cutter bodies with the same geometry but made out of different alloys. Pre-hardened steel and conventional tool steel were investigated in order to highlight the advantages of selecting correct material to achieve high performance tools with respect of chatter resistance. The experimental part of this paper consists of impact testing, machining tests and surface integrity measurements. Operational dynamic parameters obtained through auto-regressive moving average model estimates from machining tests under stable and unstable conditions was used to characterise the performance. The findings are in correlation with material damping research and chatter analysis, thus giving a strong coupling to material selection in tool holders for enhanced process stability. The research also shows that operational dynamic properties obtained through indirect measurements is a valuable tool for process stability characterisation.