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  • 1.
    Aganovic, Dario
    KTH, Superseded Departments, Production Engineering.
    On Manufacturing System Development in the Context of Concurrent Engineering2004Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    This thesis presents an extension of the contemporaryengineering design theory towards a unified view onsimultaneous development of products and manufacturing systems,i.e. concurrent engineering.

    The traditional engineering design theory explains therealization of a product design as a development of productstructure from four perspectives: technical process, function,technical solution, and physical embodiment. This thesisextends the engineering design theory with a set of definitionsand universal statements. These definitions and universalstatements describe manufacturing systems from same fourperspectives. In that context they also describe therelationship between a product and its manufacturing system.The thesis contributes to the creation of a single theoreticalsystem based on an integration of theories from two engineeringdesign schools, the WDK and the Axiomatic Design. WDKtheoriesare in this new context utilized for qualitative synthesis ofthe developed artifacts, while the Axiomatic Design is utilizedfor structuring and analyzing the corresponding quantitativeparameters.

    The definitions and universal statements describe thedevelopment structures for productsand manufacturing systems.This description is utilized for definition of a system fordevelopment of these structures, i.e. (i) a stage-gate-basedmanufacturing system development process, (ii) a developmentmethodology toolbox, and (iii) an information managementframework consisted of an information model harmonized with thesystems engineering data management standard STEP AP 233.

    The research has been carried out in a close collaborationwith Swedish manufacturing industry. The utilized researchmethodology is the hypothetic- deductive method, with casestudy as an observation method.

    Keywords:Concurrent Engineering, Engineering Design,Development Methods and Tools, Manufacturing System,Information Management.

  • 2.
    Aganovic, Dario
    et al.
    KTH, Superseded Departments, Production Engineering.
    Bjelkemyr, Marcus
    KTH, Superseded Departments, Production Engineering.
    A Model for Project-Based Education in Manufacturing System Design and Its Application on Testing Research Results2004In: 8th International Design Conference - Design 2004, 2004, p. 583-594Conference paper (Refereed)
  • 3.
    Aganovic, Dario
    et al.
    KTH, Superseded Departments, Production Engineering.
    Bjelkemyr, Marcus
    KTH, Superseded Departments, Production Engineering.
    Lindberg, Bengt
    KTH, Superseded Departments, Production Engineering.
    Applicability of Engineering Design Theory on Manufacturing System Design in the Context of Concurrent Engineering2004In: Methods and Tools for Co-operative and Integrated Design, Dordrecht, Netherlands: Kluwer Academic Publishers , 2004, p. 145-158Chapter in book (Other academic)
    Abstract [en]

     

    The relationship between a product and a manufacturing system is addressed in various engineering design theories. The different approaches in the engineering design field are mainly focused on product design. The purpose of this paper is to review theories in the area of engineering design, in order to discuss applicability of engineering design theories on the concurrent product and manufacturing system development. The reviewed theories are: Axiomatic Design, Robust Design, Theory of Domains, and Theory of Technical Systems.

  • 4. Almström, Peter
    et al.
    Mårtensson, Pär
    KTH, Superseded Departments, Production Engineering.
    Functional coupling in manufacturing systems and its implications2002In: Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture, ISSN 0954-4054, E-ISSN 2041-2975, Vol. 216, no 4, p. 623-626Article in journal (Refereed)
    Abstract [en]

    The axiomatic design theory as stated by Suh has proven useful when designing products, and this success has led to an increasing interest in applying the theory to manufacturing systems development. The theory states that functional couplings should be avoided in general. However, manufacturing systems are potentially coupled in many ways, the most obvious being that manufacturing operations usually are performed in a sequence. Functional coupling is defined as a dependence between functional requirements. The subject of couplings in manufacturing systems is not extensively explored or described in the literature, and specifically not in relation to the axiomatic design theory. Five different categories of couplings in manufacturing systems are described and exemplified in this paper. Couplings can be designed into the manufacturing system for a diverse range of reasons, e.g. selection of manufacturing processes or materials, but they may also be irrational, e.g. decisions based on political opinions.

  • 5.
    Alsterman, Henric
    KTH, Superseded Departments, Production Engineering.
    Strategic issues for achieving sustainable automatic assembly2004Doctoral thesis, monograph (Other scientific)
  • 6.
    Alsterman, Henric
    KTH, Superseded Departments, Production Engineering.
    Towards hyper-flexible assembly automation: Developemnt of hyper-flexible assembly system concept for lightmechanical assembly2001Licentiate thesis, monograph (Other scientific)
  • 7.
    Alsterman, Henric
    et al.
    KTH, Superseded Departments, Production Engineering.
    Barata, José
    Onori, Mauro
    KTH, Superseded Departments, Production Engineering.
    Evolvable Assembly System Platforms: Opportunities and Requirements2004In: The proceedings of the IMG04 conference / [ed] Rezia Molfino, 2004, p. 18-23Conference paper (Refereed)
  • 8.
    An, Wei
    KTH, Superseded Departments, Production Engineering.
    Industrial applications of speckle techniques2002Doctoral thesis, comprehensive summary (Other scientific)
  • 9.
    Andersson, Tommy
    KTH, Superseded Departments, Production Engineering.
    PRODUCT FLEXIBILITY IN AUTOMOTIVE ASSEMBLY SYSTEMS A Method for Analysis in Early Stage Design of Assembly Equipment2000Licentiate thesis, monograph (Other scientific)
  • 10.
    Axelson, Daniel
    KTH, Superseded Departments, Production Engineering.
    Systematic design of competitive production systems: towards a decision model for manufacturing system layout and organisation design2004Licentiate thesis, monograph (Other scientific)
  • 11. Barata, José
    et al.
    Onori, Mauro
    KTH, Superseded Departments, Production Engineering.
    Agile Assembly Systems: A New Shop Floor Architecture2004Conference paper (Refereed)
  • 12.
    Bayard, Ove
    KTH, Superseded Departments, Production Engineering.
    Investigation of Forces and Contact Area for Modelling Turning Processes2003Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    This thesis is focused on an investigation of forces andcontact area for modelling turning processes. The primary taskin short term research has been to take a first steptowards animproved model of the cutting process. The ultimate goal is tofind predictive models and thereby reduce the number of cuttingtests necessary to perform before an“unknown”tool-material combination can be considered for machining.Today, lot of time and money is spent to gather appropriatecutting data and material parameters. This is, nevertheless,necessary to understand and characterise the fundamentalbehaviour of a workpiece, when it is machined.

    To describe the complicated nature of the deformationprocess in cutting, analytical shear plane models are oftenemployed. In this thesis, a review of some classic models ispresented. The validity of a proposed model can be confirmed ifthe values generated can be correlated to experimental results.A difficulty is often to find a method that gives the desiredexperimental parameters. An important source for information isthe samples generated through Quick Stop tests. A reliableQuick Stop Device (QSD) has therefore been developed and ispresented in the thesis.

    Since the focus for this investigation has been to propose atentative model for cutting forces in turning, a number offorce measurements have been performed. Two different steelgrades have been evaluated in orthogonal machining, AISI-1045and AISI-12L13. Cutting force measurements (feed- and maincutting force), were conducted with a high accuracydynamometer. To investigate contact area conditions, Quick Stopspecimens, chips and inserts were examined. The evaluation wasperformed both in an Optical Light Microscope and a ScanningElectron Microscope. Three different models can be used tocharacterise the contact area. According to the contactconditions these models refer to sticking friction, flow-zoneand sliding friction region.

    Results from model simulations were fitted to those ofexperimental cutting investigations in order to evaluate theaccuracy of the cutting force and contact area approach. Thetest results are also used as reference data for a proposedsimple tentative model presented in this thesis. The model isrestricted to orthogonal machining. The proposed model consistsof several steps. The first step is to determine the maincutting force Fc. Expressions that describe Fcas a function of the cutting velocity (vc) for different feed (f) values have been derived.To be able to evaluate the feed force, the contact length lchas first to be determined. Relationships where lcis expressed as a function of vcfor different feeds have been derived. Tocalculate the feed force, a formula for Ff/Fcas a function of lcis applied. Equations for determining&#923, hchand&#934 have also been derived. In short,the functions found are: Fc= f(vc; f), lc= f (vc; f), Ff= f(Fc; lc),&#923 = f(lc; f) and&#934 = f(vc; f).

    This research work shows that it is of utmost significance,in order to generate realistic values, that a predictive modelis supported by adequate reference data. It is also shown thatthe contact area is an important parameter that has to beconsidered in modelling.

    Keywords:Modelling, turning processes, cutting forces,contact length, Quick Stop Device, QSD, simulation programs,FEM, predictive models.

  • 13.
    Bayard, Ove
    KTH, Superseded Departments, Production Engineering. KTH, Superseded Departments, Materials Processing.
    Investigation of the verification techniques for modelling turning processes2000Licentiate thesis, monograph (Other scientific)
  • 14.
    Bejhem, Mats
    KTH, Superseded Departments, Production Engineering.
    Machining Monitoring and Control: Based on Parametric Modelling2001Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    The objective of this work was the development of aMachining Control prototype system for turning, whichintegrates three fundamental aspects of Machining Controltechnology: Monitoring, Control and Optimisation. MachiningControl refers to the detection and automatic handling ofdisturbances in machining processes. Consequences ofdisturbances can be classified in three major groups:Breakdowns, production rejects and non-optimal production. Byminimising these consequences, the efficiency of the machiningprocess can be improved, which in turn will have a major impacton productivity, machining economy and product quality as well.This calls for user friendly supervisory systems that cansupport the human operator and perform monitoring, control andoptimisation tasks, i.e. Machining Control (MC) systems.

    The MC system presented in this thesis is developed around aturning centre, and consists basically of a PC equipped with amodular DSP multiprocessor, sensor systems for vibration andcutting force measurements, as well as machine tool interfaces.The basic structure of the MC system allows flexibleimplementation of tasks, which can interact with the machinetool controller and other auxiliary devices. In other words,the MC system combines virtually all essential features toperform advanced real time supervision.

    An important aspect in the development of this MC system wasthe access to accurate data, reflecting the underlyingmachining process. Therefore, the turning centre is equippedwith an integrated dynamometer and an acoustical sensor systemthat have access to the tool-workpiece interface. To ensurereliable cutting force measurements, a three-axis calibrationmethod has been developed that performs a transformation ofoutput signals from the force sensor system to accurate cuttingforces at the tool tip. A good knowledge of tool vibration andinstantaneous cutting forces allows the safer use of moreaggressive machining operations, thus utilising most of theavailable tool life withoutcausing costly breakdowns andproduction rejects.

    Two MC functions for in-process tool condition monitoringhave been developed and are discussed from both theoretical andexperimental point of view. Classical models have been used toanalyse the dynamic behaviour of the machining system, whileparametric modelling was employed for in-process monitoring andcontrol of dynamic stability. It is shown that an efficientcontrol of dynamic stability only can be performed if propertooling is selected. Some efficient solutions for improving thedynamic properties of tooling are presented. Finally, a modulefor an automatic optimisation of cutting conditions isdescribed. This module takes advantage of all the features thatare implemented in the MC system.

    This research work shows a successful application of anintegrated MC system for an effective combination betweenpeople and technology in future manufacturing systems.

    Keywords:Machining Control, tool condition monitoring,in-process dynamic stability monitoring and control,optimisation of cutting conditions, MC, DSP, TCM

  • 15.
    Beno, Tomas
    KTH, Superseded Departments, Production Engineering.
    Heat generation and heat transfer ib drilling operations2001Licentiate thesis, monograph (Other scientific)
  • 16.
    Beno, Tomas
    KTH, Superseded Departments, Production Engineering.
    Simulation, verification and control of heat transfer in machining2004Doctoral thesis, monograph (Other scientific)
  • 17.
    Bjelkemyr, Marcus
    et al.
    KTH, Superseded Departments, Production Engineering.
    Lindberg, Bengt
    KTH, Superseded Departments, Production Engineering.
    On complexity and uncertainty in a manufacturing system design process2004In: International Conference on Axiomatic Design, ICAD, 2004, Vol. 4Conference paper (Refereed)
  • 18.
    Björkman, Emma
    KTH, Superseded Departments, Production Engineering.
    Dimensional errors caused by thermal instability in grinding machines2001Licentiate thesis, monograph (Other scientific)
  • 19.
    Boivie, Klas
    KTH, Superseded Departments, Production Engineering.
    On the Manufacturing of SFF Based Tooling and Development of SLS Steel Material2004Doctoral thesis, monograph (Other scientific)
  • 20.
    Boivie, Klas
    KTH, Superseded Departments, Production Engineering.
    On the manufacturingof Sff based tooling and development of SLS steel material2002Licentiate thesis, monograph (Other scientific)
  • 21.
    Carlsson, Torgny E.
    et al.
    KTH, Superseded Departments, Production Engineering.
    Nilsson, B.
    Gustafsson, J.
    System for acquisition of three-dimensional shape and movement using digital Light-in-Flight holography2001In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 40, no 1, p. 67-75Article in journal (Refereed)
  • 22.
    Carlsson, Torgny E.
    et al.
    KTH, Superseded Departments, Production Engineering.
    Stjernstoft, T.
    A model for calculation of the geometrical shape of the cutting tool - Work piece interface2001In: Cirp Annals-Manufacturing Technology, ISSN 0007-8506, Vol. 50, no 1, p. 41-44Article in journal (Refereed)
  • 23.
    Carlsson, Torgny E.
    et al.
    KTH, Superseded Departments, Production Engineering.
    Wei, A.
    Phase evaluation of speckle patterns during continuous deformation by use of phase-shifting speckle interferometry2000In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 39, no 16, p. 2628-2637Article in journal (Refereed)
  • 24. Chiroiu, V.
    et al.
    Munteanu, L.
    Nicolescu, Cornel Mihai
    KTH, Superseded Departments, Production Engineering.
    Shape description of general 3D object using tactile sensing information2004In: Advances in Modelling and Analysis B, ISSN 1240-4543, Vol. 47, no 5-6, p. 81-90Article in journal (Refereed)
    Abstract [en]

    In this paper we consider the problem of recognizing the shape of a 3D object using tactile sensing by a dexterous robot hand. Our approach uses multiple fingers to slide along the surface of the object. From the sensing contact points we extracts a number of 3D points belonging to the surface of the object. The unknown surface Γ of the object is determined by using an "n-ellipsoid" model (Bonnet [4]). The set of parameters that define the surface Γ is determined such that the nellipsoid best fits the set of data points, by using a genetic algorithm.

  • 25.
    Eriksson, Conny
    KTH, Superseded Departments, Production Engineering.
    Roll pass design for improved flexibility and quality in wire rod rolling2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The thesis treats roll pass design in wire rod rolling of stainless steel for sequences and series built up by two-symmetrical grooves. It is focused on predicting rolling flexibility, also called working range, as well as product quality. For analysing the flexibility a computer program has been developed. The minimum and maximum roll gap and corresponding bar areas for series of grooves including "oval", "round", "false round", "square" and "diamond" shapes are calculated. Six pass designs used in Swedish mills are analysed. Full-scale rolling is compared with laboratory experiments for the square-oval and false round (round)-oval series. The false round-oval series offers the largest working range and that the flexibility is smaller for pass sequences designed for high reductions. The false round-oval series are also acknowledged as a series for high quality steels and are usually better than the square-oval series having a tendency for defect formation. The thesis also includes high-speed rolling of wire rod in blocks. Here interstand tensions are utilised in order to keep the process stable. For obtaining the required dimensional tolerances of the product they are kept as low as possible. However interstand tensions could be used in order to increase the working range and move the product range towards smaller wire cross sections. For analysing this possibility, a narrow spread technology is utilised. At present time a practical problem is referred to the fixed gearings in the common blocks, which require a certain and given level of interstand tensions and corresponding reductions. This problem can however be solved by means of new block design and modern process control technology. Roll stands can be separately driven and controlled at very high speeds. Thus the eight stand blocks can be subdivided into four plus four passes blocks with a cooling line between enabling also higher productivity without violating the product quality because defect formations caused by a too high rolling temperature. The true working range of a series for a specific steel grade is however not only dependent on the possible spectrum of wire dimensions that can be obtained but might also depend on its ability to decrease or eliminate defects such as surface cracks. Thus, the behaviour of artificial V-shaped cracks in the longitudinal direction has been investigated and compared for the square-oval and false round (round)-oval series mentioned above. In agreement with other research works it was established that efficient rolling conditions for reducing the cracks are obtained when the cracks open up at the same time as their depth is reduced. If the V-shaped crack is closed by contact between its oxidized side surfaces the rolling schedule is not optimal for getting a high quality product. A deeper understanding of the experimental results was obtained by means of an FE-analysis

  • 26.
    Eriksson, Conny
    KTH, Superseded Departments, Production Engineering.
    Surface cracks in wire rod rolling2004In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 75, no 12, p. 818-828Article in journal (Refereed)
    Abstract [en]

    Surface defects in wire rod and bar rolling are common and well-known to mill people. Nowadays, surface defects are not accepted on high-alloyed steel wire rods. The steel making, casting and rolling processes give rise to defects. Also, the final handling of the wire and bar can destroy the surface. In this work, artificial V-shaped cracks in the longitudinal direction were investigated for different reduction series. The false round-oval series are known as a series for high quality steels and are usually better than square-oval series. Experiments confirmed that in the false round-oval sequences a surface crack in the groove bottom may open up during rolling at the same time as its depth is reduced, which is a beneficial situation. Surface cracks found at 45degrees to the rolling direction, at groove "corners" and on free surfaces will be closed or reduced in depth. The closing of cracks is detrimental since the cracks usually hide rolled-in oxides beneath the bar surface. The experiments showed that for the subsequent oval-false round sequence the visible crack at the groove bottom will be closed and become shallower. The cracks at 45degrees and on the free sides will also be closed, but deeper causing a serious surface defect. An FE-analysis was carried out, explaining the experimental results. Flat oval grooves are better than round ovals and false rounds are superior to square for opening and decreasing the depth of a longitudinal crack. It is difficult to eliminate a surface defect constituting a closed crack.

  • 27.
    Eriksson, Conny
    et al.
    KTH, Superseded Departments, Production Engineering.
    Lundberg, S.-E.
    Working range of roll pass sequences in wire rod rolling with interstand tensions2004In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 31, no 1, p. 81-92Article in journal (Refereed)
    Abstract [en]

    In the high speed rolling of wire rod in blocks, interstand tensions are utilised in order to keep the process stable. However, interstand tensions influence the rolling process, and especially the spread and forward slip, which are dependent of tensions between the stands. By the influence on spread, the tolerances of the rolled product depend on the tensions and usually the interstand tensions are kept as low as possible in order to obtain required tolerances. A narrow spread technology is used to utilise interstand tensions in order to increase the working range of a pass sequence and move the product range towards smaller sizes. By adapting a certain amount of interstand tensions, smaller sizes can be rolled by a given roll pass schedule. A practical problem in this method is the fixed gearings in the common blocks, which require a certain and given level of interstand tensions and corresponding reductions. In the latest generation of blocks, where the stands are arranged in units, two by two, with each unit driven by a dedicated electrical motor, it is possible to introduce 'inter unit' tensions, and by this method extend the working range of the pass sequence. A special computer program for analysis of interstand tensions has been developed by combining a program TENSION, developed at the Royal Institute of Technology in Stockholm, dealing with the basic principles of rolling with interstand tensions, with the recently published program WORKRAN, which analyses the working range of any roll pass sequence built up by common two-symmetrical grooves. From the analysis and experimental data it is shown that interstand tensions at the level of 10% of the yield stress of the material increase the working range in a six stand block by 2% and reduce the lower limit of the exit section area by about 15%. Higher tension levels have a larger effect both on the extension of the working range and on the reduction of the minimum exit area but it becomes more difficult to control the tolerances at higher tension levels. The influence of interstand tensions on the reduction and on the working range of the pass sequence is mainly obtained by the influence on the round passes, while the oval passes have a counteracting effect on the influence of interstand tensions.

  • 28.
    Eskilander, Stephan
    KTH, Superseded Departments, Production Engineering.
    Design for automatic assembly2001Doctoral thesis, monograph (Other scientific)
  • 29.
    Fjellstedt, Carl Jonas
    KTH, Superseded Departments, Production Engineering.
    Crystallisation Processing of Al-base Alloys2001Doctoral thesis, comprehensive summary (Other scientific)
  • 30.
    Ghiassi, Behnam
    KTH, Superseded Departments, Production Engineering.
    Evaluation of temperature distribution on carbide cutting tools using IR-technique2001Licentiate thesis, monograph (Other scientific)
  • 31. Granberg, H.
    et al.
    Jensen, J.
    Mattsson, Lars
    KTH, Superseded Departments, Production Engineering.
    Forward scattering of fiber-containing surfaces studied by 3-D reflectance distribution simulations and measurements2003In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 42, no 8, p. 2384-2390Article in journal (Refereed)
    Abstract [en]

    Recent studies have shown that the angular distribution of diffuse reflectance, obtained from bidirectional reflectance distribution function (BRDF) measurements, differs strongly between paper sheets with and without fibers present in the top surface layer. For fiber-containing surfaces, in contrast to pigment-coated paper surfaces, there is a distinct forward scattering at angles much larger than the specular reflection angle. In the search for an explanation of this phenomenon, we have made calculations of reflectance distributions of a simulated paper web, containing randomly distributed hollow fibers. We did this on the assumption that fibers present in paper are considerably larger than the wavelength of visible light, and that the surface microroughness of the fibers can be treated as a diffraction broadening superposed on the ray calculated reflectance distribution. We investigate whether the structural shape and distribution of wood fibers can explain some of the observed forward-scattering phenomenon. We also compare these Monte-Carlo ray tracing calculations qualitatively with experimental BRDF measurements of the diffuse reflectance from a fiber-containing surface. From the calculations we found that the reflection at the inner fiber wall of the hollow fibers constituting the topmost layer plays a major role in forming a forward-scattering reflectance distribution. We also found that the Monte-Carlo-calculated bulk scattering distribution, i.e., the distribution of reflected light after a large number of reflections within the web structure, tended to be elongated perpendicular to the sheet plane of the fiber web, rather than being uniform.

  • 32. Granberg, H.
    et al.
    Rundlof, M.
    Mattsson, Lars
    KTH, Superseded Departments, Production Engineering.
    Influence of surface-induced nonuniform reflectance on the diffuse reflectance factor. Part I: Model predictions2003In: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 29, no 8, p. 247-253Article in journal (Refereed)
    Abstract [en]

    The Kubelka Munk (KM) model is used frequently as a tool to design paper to reach a desired opacity and whiteness. The input data in this modelling, the scattering and absorption coefficients, are commonly derived from diffuse reflectance factor measurements. The quality of the coefficient values is dependent on the structure of the samples and the backings from which they were obtained. In this paper we focus on modelling the influence of nonflectance factors obtained using the d/0degrees standardized uniform reflectance induced by the surface structure, and how it affects the diffuse reflectants factors obtained using the d/0degrees standardized measurement geometry. From the analysis, we conclude that the structure of the surface facing the detector may have a significant effect on the instrument readings depending on whether the sample is glossy or reflects diffusely from the surface. Based on this surface reflectance, we analyze various situations of relevance for the papermaker and show that common-practice application of the KM model to reflectance factor measurements may lead to serious misinterpretations.

  • 33. Granberg, H.
    et al.
    Rundlof, M.
    Mattsson, Lars
    KTH, Superseded Departments, Production Engineering.
    Influence of surface-inducled nonuniform reflectance on the diffuse reflectance factor. Part II: Experimental verification on coated substrates2003In: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 29, no 8, p. 254-259Article in journal (Refereed)
    Abstract [en]

    Many authors have found that the Kubelka-Munk (KM) scattering coefficient, s(c), of a coating applied to a substrate decreases with increasing coat weight. This decrease is usually explained by a structural/porosity change with coating thickness or a penetration of the coating into the paper In this paper we propose an alternative explanation to the observed decrease in sc, namely the misinterpreted diffuse reflectance factors for non-Lambertian reflecting substrates and coatings. This explanation was recently proposed by the authors; the second part presented here provides experimental support for the presence of a nonuniform reflectance distribution and its influence on KM fitted data. Three different coated systems are considered, using a transparent film, abase paper and a synteape film as substrate. The effect of the surface reflectance of the substrate and of the coated substrate can explain the apparent decrease in sc as an artifact when measuring a sample with an instrument having a d/0degrees geometry.

  • 34.
    Granberg, Hjalmar
    KTH, Superseded Departments, Production Engineering.
    Light scattering in paper: angle-dependent light scattering measurements and analysis2001Licentiate thesis, comprehensive summary (Other scientific)
  • 35.
    Granberg, Hjalmar
    KTH, Superseded Departments, Production Engineering.
    Optical Response From Paper: Angle-dependent Light Scattering Measurements, Modelling, and Analysis2003Doctoral thesis, comprehensive summary (Other scientific)
  • 36.
    Gröndahl, Peter
    et al.
    KTH, Superseded Departments, Production Engineering.
    Onori, Mauro
    KTH, Superseded Departments, Production Engineering.
    Standardised flexible automatic assembly - evaluating the Mark IV approach2000In: Assembly Automation, ISSN 0144-5154, E-ISSN 1758-4078, Vol. 20, no 3, p. 217-224Article in journal (Refereed)
    Abstract [en]

    The Assembly Systems Unit at the Royal Institute of Technology and IVF Stockholm has developed several Flexible Automatic Assembly (FAA) cell solutions over the years (Mark I. Mark II, Mark IIF and Mark III). The industrial reality, however, clearly points out that the basic notions of flexibility must be extended and be enhanced without increasing the complexity. This has led our research team to revise the ideas and solutions available for manual and automatic assembly, resulting in the Hyper Flexible Automatic Assembly (HFAA) project. The paper describes the driving factors behind the needs and objectives for the HFAA project, as well as how it will present a standardised set of assembly process-oriented system components. The paper also describes the new Mark IV application. This industrial HFAA system is being developed in order to test the concept's industrial viability. The HFAA concept will allow the user to start from a manual assembly station and gradually add assembly equipment. The basic concepts of stepwise automation, standard assembly machine and sub-batch principle emanate from our previous research.

  • 37.
    Grünberg, Thomas
    KTH, Superseded Departments, Production Engineering.
    Performance improvement2003Licentiate thesis, monograph (Other scientific)
  • 38.
    Gustafsson, Jonny
    et al.
    KTH, Superseded Departments, Production Engineering.
    Lindfors, Christoffer
    KTH, Superseded Departments, Production Engineering.
    Development of a 3D interaction table2004In: STEREOSCOPIC DISPLAYS AND VIRTUAL REALITY SYSTEMS XI / [ed] Woods, AJ; Merritt, JO; Benton, SA; Bolas, MT, BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING , 2004, Vol. 5291, p. 509-516Conference paper (Refereed)
    Abstract [en]

    We have identified the need for, and started development of, a new tool we call an interaction table. In this paper the experiences with the first prototype are described. The interaction table presents a computer-generated, autostereoscopic, three-dimensional image that can be viewed and interacted with.

  • 39. Gårdstam, Johannes
    et al.
    Melander, Arne
    KTH, Superseded Departments, Production Engineering.
    Self-piercing riveting of stainless steel sheets: simulation and verification2004In: 11th Paderborner Symposium Fügetechnik, LWF Labor fur Werkstoff und Fugetechnik der Universität Paderborn , 2004, p. 135-143Conference paper (Refereed)
  • 40.
    Han, Han
    KTH, Superseded Departments, Production Engineering.
    Determination of Coefficient of Friction and Anisotropy in Metalworking2003Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The work material in metal working operations always showssome kind of anisotropy. To simplify the theoretical analysis,anisotropy is usually neglected and the material is assumed tobe isotropic, especially in determination of coefficients offriction. For predicting the material flow during plasticdeformation and for predicting the final material properties ofthe product, adequate descriptions of both coefficients offriction and flow stress curves have to be developed.

    In the present work, a new pattern describing the influenceof friction and anisotropy on material flow has been identifiedand verified by means of 3D-FEM analyses and experiments inring compression tests. Results reveal that the influence ofanisotropy on the ring deformation is quite similar to thatobtained by changing the frictional condition. If the influenceof anisotropy on material flow is incorrectly attributed tofriction, the possible error of the coefficient of friction canbe as high as 80% for a pronounced anisotropic material.

    Similar results have also been obtained from 2D-FEM analysesof upsetting, extrusion and rolling processes becauseanisotropy can have a significant effect on the shear strain inthe contact surface layer. In a rolling process, results showthat shear strain can be reduced by changing rolling parametersand the shear strain value can be an indicator to evaluate thedegree of optimization of the process.

    To determine the coefficient of friction and flow stress foranisotropic material, a modified two-specimen method (MTSM) hasbeen established using an inverse method. The method has beenapplied to cylinder upsetting, Rastegaev specimen upsetting,plane strain compression tests and rolling processes. Resultsshow that MTSM is able to evaluate the validity of mathematicalmodels when both the coefficient of friction and the flowstress are unknown and can also determine the coefficient offriction and flow stress provided that the selectedmathematical model is adequate. Regarding rolling, it is shownthat the Ekelund model combined with the Hitchcock equationmodified by Roberts gives the most accurate value of frictioncoefficient and flow stress in comparison with other forcemodels and equations.

    A number of experimental methods (yield loci, strain ratiosand multi-directional flow stress-curves) for determining theanisotropy have been compared. Results show that the yield locimeasurements are weak in predicting anisotropy when thematerial strain hardening differs in different directions. Itis also concluded that strain ratio (R-value) measurements areunreliable for describing anisotropy. The most reliable anduseful results were derived from multi-direction determinationsof the flow stresses.

    Key words:Coefficient of friction, anisotropy, flowstress, modified two-specimen method (MTSM) and FE-analysis

  • 41.
    Han, Han
    KTH, Superseded Departments, Production Engineering.
    Determination of Flow Stress and Coefficient of Friction for Extruded Anisotropic Materials under Cold Forming Conditions2002Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The work material in metal working operations always showssome kind of anisotropy. In order to simplify the theoreticalanalysis, especially considering bulk deformation processes,anisotropy is usually neglected and the material is assumed tobe isotropic. On the other hand, the analysis that consideredthe influence of anisotropy seldom incorporates the influenceof friction. For predicting the material flow during plasticdeformation and for predicting the final material properties ofthe product, adequate descriptions of both flow stress curvesand coefficients of friction have to be developed.

    In the present work a number of experimental methods fordetermining the anisotropy have been utilized and compared:Yield loci, strain ratios (R-values) and establishing flowstress-curves in different directions. The results show thatthe yield loci measurements are weak in predicting anisotropywhen the material strain hardening is different in differentdirections. It is concluded that also the strain ration(R-value) measurements are unreliable for describinganisotropy. The most trustable and useful results were foundfrom multi-direction determinations of the flow stresses.

    Three typical cases of ring upsetting conditions wereanalyzed by theory (3D-FEM) and experiments:

        An anisotropic ring, oriented 900 to the axis ofrotational symmetrical anisotropy. The friction coefficientwas the same in all directions

        An isotropic ring. The friction coefficient was differentin different directions

        An anisotropic ring oriented 00 to the axis of rotationalsymmetrical anisotropy. The friction coefficient was the samein all directions

    The cases 1) and 2) reveal that the influence of anisotropyon the ring deformation is quite similar to that obtained bychanging the frictional condition. The case 3) exposes that ifthe material flow caused by anisotropy is incorrectly referredto friction, the possible error of the friction coefficient canbe as high as 80% for a pronounced anisotropic material. Amodified two-specimen method (MTSM) has been establishedaccording to an inverse method. Experiments were carried ascylinder upsetting. Here both ordinary cylinders were used aswell as so-called Rastegaev specimen. Also plane straincompression tests were utilized. The results show that MTSM isable to evaluate the validity of a selected mathematical modelwhen both the friction coefficient and the flow stress areunknown for a certain process. MTSM can also be used toestimate the friction coefficient and flow stress provided thatthe selected mathematical model is adequate.

    Key words:Anisotropy, friction coefficient, flowstress, modified two-specimen method and FE-analysis

  • 42.
    Hansson, Karin
    KTH, Superseded Departments, Production Engineering.
    On the hot crack formation during solidification of iron-base alloys2001Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Hot cracking during solidification is a severe problem inmany casting processes, for example in continuous casting.Combinations of low strength and low ductility of the materialat high temperatures and applied tensile stress can cause hotcracking. In order to investigate the hot crack susceptibilityof several iron-base alloys, the transition temperature betweenbrittle and ductile fracture, TDB, was determined by high temperature tensiletesting of 'in situ' solidified samples using cooling rates inthe range of 10-1900ºC/min.

    Fe-Ni alloys, including Invar steel, with a narrowsolidification interval, and Fe-Cu alloys, with a broadsolidification interval, were investigated. The compositionswere selected to study both solidification to austenite and toferrite. The ferritic solidifying Fe-Cu and Fe-Ni alloys werenot sensitive to hot cracking, as the brittle ductiletransition temperature occurred near the solidus temperatureand was not affected by various cooling rates. The austeniticsolidifying Fe-Cu alloy was very sensitive for hot crackingasall samples fractured in the brittle mode in the testedtemperature range. The austenitic solidifying Fe-Ni alloys werealso very susceptible for hot cracking, as the ductile/brittletransition occurred more than hundred degrees below the solidustemperature and with decreased cooling rate, TDBwas decreased. The results found in the Fe-Nialloys could not be explained by the presence of liquid films.In order to explain the observations of the Fe-Ni alloys a newtheory was proposed and analysed. It suggested thatsupersaturation of vacancies formed during the solidificationprocess will initiate a crack and favour the growth of thecrack by vacancy diffusion.

    The hot cracking susceptibility of commercial alloys wasalso determined, such as rock tool steel, free cutting steeland stainless steel. It was shown that the primary austeniticsolidifying stainless steels were much more sensitive for hotcracking and various cooling rates compared to the primaryferritic solidifying stainless steels.

    Copper is notorious for causing hot cracks in steels. Inorder to study hot cracking in presence of liquid films,experiments of liquid copper penetration into iron grainboundaries were investigated. A new theory was proposed for thepenetration process and included the Kirkendall effect, i.e. anuneven diffusion of Cu an Fe will generate vacancies which willdiffuse and condense at grain boundaries. High temperaturetensile tests were also performed on an Fe-10%Ni alloy duringliquid copper penetration in order to study how the penetrationprocess was affected by applied tensile stress. Microprobemeasurements across a crack gave a diffusion constant, whichwas at least 1000 times the value found in literature. Itshowed that there was an enhanced diffusion process caused bystraining the lattice.

    Keywords:hot cracking, hot tearing, cracking(fracturing), tearing, ductility, brittleness, embrittlement,fractures, ductile brittle transition, solidification, iron,copper, nickel, Invar, steels, free machining steels, stainlesssteels, penetration, crack initiation, crack propagation,lattice vacancies, diffusion.

  • 43.
    Hansson, Per
    KTH, Superseded Departments, Production Engineering.
    Control of weldability: Research leading to the development of two new quenched and tempered tool steels2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The understanding of the hardenability is important in steel development with respect to weldability of steels as well as to the design of quenched and tempered steels.The common way to judge if steel is suitability to welding is the use of a carbon equivalent, which reflects the alloy content to the hardenability of the heat affected zone (HAZ). Most common of these equivalent is the IIW carbon equivalent wich has been in use for decades.

    However, this is an empirical equivalent, developed for CMn steels, and it doesn't say anything about the mechanical properties obtained in the HAZ. As a guideline a maximum HAZ hardness of 350 HV is normally put to avoid cold cracking in the HAZ. Numerous carbon equivalents have been published during the years, but few have been accepted and used. A drawnback of all these equivalents is that they have been evaluated for a set of chemical compositions which may be quite narrow, or that they have been evaluated on steels produced having other cleanliness, residual element levels etc. as is common in modern steelmarketing.

    The hardenability of steel designated to quenching and tempering is normally evaluated using either Jominy testing or using a calculation using the Grossmann formalism. As the hardenability described in the carbon equivalents used in welding and the hardenability of quenched and tempered steels using the Grossmann formalism are two different descriptions of the same phenomenon the aim of this thesis is to link these two formalisms together and use the knowledge from the HAZ hardenability to design quenched and tempered steels. The goal is to produce such steel grades having a much better weldability as compared with standard grades available at the market.

    In this work the hardenability in the heat affected zone (HAZ) in weldments in high strength low alloyed steels (HSLA steels) having a yield strength of 350 MPa. This part microalloying elements on the phase transformations which take place during cooling from the peak temperature of the welding cycle. These results have been linked to the mechanical properties of the HAZs.

    In the second part of this thesis the development of tool steel grades with respect to optimise both hardenability with respect to;

    - matrix hardenability (i.e the Grossmann approach)

    - an enhanced weldability of such new steels due to a lower alloying content than is usual in such grades

  • 44.
    Holmström, Patrik
    KTH, Superseded Departments, Production Engineering.
    A data exchange during the realisation process of machining manufacturing equipment: a field studyManuscript (Other academic)
  • 45.
    Holmström, Patrik
    et al.
    KTH, Superseded Departments, Production Engineering.
    Kjellberg, Torsten
    KTH, Superseded Departments, Production Engineering.
    Modelling manufacturing resource capability: a discussion of the industrial benefits2004In: Proceedings of the 37th CIRP International Seminar of Manufacturing Systems, 2004, p. 79-82Conference paper (Refereed)
  • 46.
    Holmström, Patrik
    et al.
    KTH, Superseded Departments, Production Engineering.
    Von Euler-Chelpin, Astrid
    KTH, Superseded Departments, Production Engineering.
    Manufacturing system capability representation with runtime information for reliable prediction of produced output2004In: Proceedings of Product Data Technology Europe 2004 13th Symposium, Stockholm, Sweden, 2004, p. 199-206Conference paper (Refereed)
  • 47.
    Huang, Qi
    KTH, Superseded Departments, Production Engineering.
    Development of a PKM control system by design, modelling, simulation and integration2001Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    PKM (ParallelKinematicMechanism) machines have received increasing interestfrom industries. Nevertheless, they didn't turn out goodresults in control performances as desired. One of the reasonsis the unsuitability of the available control systems for theparallel mechanisms.

    This thesis presents a process to develop a PKM controlsystem. The process is fulfilled by three developing groups:the control supplier, the machine builder and the machine user.By making use of the axiomatic design principle, a conceptualcontrol system is designed to meet the functional requirementsof these three groups. The design is especially focused on thetransformation module within the motion controller since thismodule mainly makes PKM control system different from othercontrol systems.

    Kinematic transformations are needed in the transformationmodule to control the PKM machines. Therefore, a transformationtheory for control is proposed to perform all computations ofthe transformations in the motion controller. The theoryincludes two parts. Part 1 introduces the inverse and forwardtransformations and the roles of singularity and dexterity inmotion control. Part 2 describes how to integrate the kinematicmodels into a control system to realise the transformationfunctions. The integration process takes place on thetransformation platform and makes it possible for a controlsupplier to co-operate with the machine builders and users.

    A new method, named a connection method, is created in thisthesis to establish the dynamic models of the PKM machines. Thepurpose is to reveal the dynamic behaviours of the PKM machinesand to design a better control model via the dynamic modelstogether with the kinematic models. This method is successfullyapplied to a planar PKM machine, PAMELA (PArallelMEchanism withLinearActuators).

    By simulation, a control model, called ISF (IntermediateStateFeedback), is suggested to eliminate the control-errorscaused by the inexact kinematic models. The simulation alsoshows that the good dexterity obtained in the machine designcan lead to good control performances. Together with thekinematic compensation, the ISF control model can improve thepositioning accuracy.

    This thesis demonstrates the whole development process ofthe PKM control system by taking the PAMELA machine as anexample. It helps to verify the development process and gives astudy case to develop other machine control system.

    Keywords: Control System Design, PKM machines, KinematicTransformation, Dynamic Modelling, Motion ControlSimulation

  • 48.
    Håkansson, Kenneth
    KTH, Superseded Departments, Production Engineering.
    Weld Metal Properties for Extra High Strength Steels2002Doctoral thesis, comprehensive summary (Other scientific)
  • 49.
    Iravani, Ebrahim
    KTH, Superseded Departments, Production Engineering.
    Laser and eddy current measuring techniques for agile manufacturing2002Doctoral thesis, monograph (Other scientific)
  • 50.
    Johansson, Mattias
    KTH, Superseded Departments, Production Engineering.
    Information Management for Manufacturing System Development2001Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    In the development of products the actual product design isnot an isolated occurrence solely providing the definitionalinformation needed to realise information into physicalproducts. There is also a need to develop and design themanufacturing process and manufacturing system that is to beused in the transformation of information into a physicalproduct. Integration of the design processes of products,processes and manufacturing systems has become important toeffectively transform knowledge into physical products. Thisdevelopment process is under a constant pressure to deliverhigher quality information in a shorter time than before. Thedrive for perfection has also forced industry to focus on thisspecific area of expertise and cooperate with partners in orderto have a complete coverage of all aspects in the productdevelopment.

    The last decade has shown a significant increased use ofcomputer applications within industry for an exact andefficient information creation. The use of computerapplications however, has not been as successful as intended.One major reason for this is due to problems in informationmanagement and communication issues were sharing of informationbetween computer applications has been a major obstacle.

    The research presented in this thesis focuses on the use ofstandardised information models as a base for an informationsystem supporting integrated design of products, processes andmanufacturing systems. The use of standardised informationmodels is key to communication and sharing of information amongcomputer applications. The development of these informationmodels has until now had a product design focus and theinformation concerned with the design of manufacturing systemshas not yet been addressed.

    In this thesis the design information of manufacturingsystems have been studied and used for the definition of aninformation model enabling communication of information amongcomputer applications used for manufacturing system design. Thedefinition of the information model has had a holistic approachwhere the integrated information management for design anddevelopment of products, processes and manufacturing systemshave been considered.

    This thesis has studied the ISO10303, STEP, standard anddefines the use of ISO10303-214 for the design information ofmanufacturing systems. This definition allows for therepresentation of integrated product, process and manufacturingsystem information through the use of one information model.This research has proposed changes to the ISO10303-214 standardin order to represent the integrated information from early todetailed design and had these changes accepted.

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