A simplified modeling approach for human system interaction

Despite increasing dependency on technology, the importance of humans is expected to increase and to provide a realistic basis for decision support; both technical and organizational processes must be included in simulation models. In a rapidly changing environment, skill development is also important and should be considered when developing simulation models. This paper describes a three step straightforward method that support the implementation of supporting (human dependent) processes, operators competence and competence development using learning curves to obtain a more representative simulation of system performance. The effect on the performance measures are also demonstrated based on a case study of a highly automated press line. The advantages and disadvantages with the proposed method are also discussed.Godkänd; 2008; 20081211 (petern

Production simulation as a management tool

This thesis focuses on process simulation and modelling in the context of production engineering. The thesis is presented in the form of seven papers which range in content from the holistic analysis of the application of modelling (papers 1-5) to a detailed examination of some of the areas of weaknesses in commercially available software (papers 6 and 7). The papers can be summarised as follows; Paper 1, The Use of Virtual Reality Tools in Complex Work Cell Implementation - Experiences from Scandinavian Industry; The main contribution of this work is a demonstration of the ability of process modelling tools to predict risks and disturbances during the implementation of robotic based manufacturing cells. Paper 2: The Virtual Arena; experiences from the first industrial application of a new AMT implementation methodology; The main contribution here is a preliminary outline of a methodological approach for the application of process modelling tools in the development and implementation of AMT (advanced manufacturing systems). Paper 3: A new Modelling Approach to Support Identification and Development of Secondary Processes in an Industrial AMT Implementation; The main contribution of this paper is a demonstration of extended process mapping and a modelling approach involving both main and supporting processes and the importance of staff competence. Paper 4: Competence requirements and their impact on manufacturing system performance; This paper explains how staff competence can be implemented into process models to obtain a more representative simulation of overall system performance. Paper 5: Modelling the impact of supporting processes on manufacturing system performance - experiences from an industrial case study. This paper demonstrates the use of the method introduced in paper 5 and its applicability in small cell configurations and SMEs. Paper 6: The effect of process interruption and scrap on production simulation models; This paper investigates an area of weakness in commercially available simulation software; the treatment of breakdown related scrapping events. The paper explains the different types of breakdown/scrapping dynamic possible for any given machine and demonstrates the effect of these scrapping dynamics on the Overall Equipment Effectiveness. The paper demonstrates (for the first time) the need for careful analysis and the correct choice of breakdown/scrapping dynamics in simulation models. Paper 7: Simulation of production lines involving unreliable machines: the importance of machine position and breakdown statistics; This paper the importance of choosing the correct values and statistical distributions for breakdown frequency and duration when simulating production line productivity. The pitfalls of making the wrong choices from those offered in commercially available software are pointed out. The paper also demonstrates that the common technique of reducing the standard deviation of variables to obtain a more deterministic model can lead to inaccurate results. Also, it is demonstrated that the productivity of a production line can be improved by simply re-arranging the order of unreliable machines in the line.Godkänd; 2008; 20080221 (ysko

Modelling the impact of supporting processes on manufacturing system performance : experiences from an industrial case study

Godkänd; 1999; 20130905 (andbra)</p

An extended feasibility study to identify laser welding and laser.arc hybrid welding business cases and business models

The laser research group at Luleå University of Technology has, in collaboration withSwedish industries, performed more than 20 laser welding and laser arc hybrid welding casestudies during the last decade. Most of them can be considered as successful and havedemonstrated improved mechanical properties, new design opportunities and higher weldingproductivity. Nevertheless, very few of the successful case studies have resulted in anindustrial application and the number of industrial implementations is still very limited. Thereare of course several reasons, like company organisation, human factors or lack of experience,but usually it is a rational analysis based on return of investment. The case studies are alsousually limited to one component at one company without any further evaluation and analysisof other business opportunities, i.e. other components/products within the company orforming a cluster of companies in a geographic region. This paper presents an extend analysesof a number of the performed case studies with the objectives to evaluate and identifybusiness cases. Different business models, such as investigate product families for laserwelding within a company and company clusters with common laser welding resource, isevaluated and analysed.Godkänd; 2013; 20131210 (andbra

Simulation of production lines involving unreliable machines : the importance of machine position and breakdown statistics

This paper demonstrates the importance of choosing the correct statistical distributions for breakdown frequency and duration when simulating production line productivity. Statistical distributions with a wide range tend to reduce the productivity of the line. Also, it is demonstrated that the productivity of a production line can be improved simply by re-arranging the order of unreliable machines in the line. If the line consists of similar or exchangeable machines, productivity can improved if the most unreliable machines are placed towards the end of the line.Godkänd; 2007; 20071119 (cira

Keeping Track of Productivity in House-Building

The broad nature of productivity leads to different interpretations and uses depending on the purpose, context and levels giving many ways for measuring productivity. However, measuring productivity in ways that reveal substantial information for operational improvements in house-building seems challenging, and methods like single-factor productivity are reported not to be common in systematic ways to that end. It is unclear how productivity is used by house-builders on-site to control, evaluate and improve operations. This study addresses how Swedish house-building companies keep track of productivity in the processes and sub-processes of production. Productivity measurements and the control of influencing factors on productivity are discussed with findings from interviews and workshops with representatives from five Swedish housebuilding companies. Results show that some productivity measurements are done in parallel with “ordinary” project management assessments to control time and cost. Yet, most factors seemingly affecting productivity are measured qualitatively and “stay in the mind” of the managers. However, some results indicate an increased understanding amongst managers for using performance indicators to track and develop activities and processes assisted with digital tools. Still, further investigation is needed to better understand how factors influencing productivity can systematically be assessed and incorporated into methods for operational development

The effect of process interruption and scrap on production simulation models

This study shows that, for many manufacturing processes (such as welding and injection moulding), a machine breakdown will result in the scrapping of a component, and goes on to explain the effect that this can have on process simulation models. Breakdown related scrapping events are ignored by commercially available process simulation packages and this reduces their usefulness in decision support. This paper explains the different types of breakdown/scrapping dynamic possible and provides equations which can be used to describe them in future generations of simulation software. This work clearly demonstrates the scrapping dynamics effect on one of the major performance measures in LEAN based manufacturing systems, namely the Overall Equipment Effectiveness.Godkänd; 2007; 20071119 (cira

Modelling the cutting geometry for laser remote fusion cutting of metals

The high brilliance fibre and disc lasers that were developed during the last decade providelong range focusing that enables remote laser techniques without assist gas, including remotelaser welding and cutting. In combination with industrial robots these lasers offer industry ahighly flexible production solution, including quick positioning with scanner optics across aworkpiece. The paper presents the state of the art in the field of remote metal cutting with thefocus on analytical models and the physical process analyses. Several remote cuttingtechniques can be distinguished, in particular remote ablation cutting, remote fusion cuttingand remote gravity cutting. The three-dimensional cutting process and kerf geometry isconcluded to an extensive impact on the melted metal flow and the cutting processperformance. A semi-analytical mathematical model has been developed that enables tocalculate and analyse the cutting front with respect to absorption, heat conduction, recoilpressure and melt film flow. Beside analysing the remote laser fusion cutting process, theregimes and their transitions from remote fusion cutting to keyhole laserGodkänd; 2013; 20131210 (andbra

Produktivitet i byggandet : Mått och mätning

Byggindustrin har under lång tid varit utsatt för kritik för bristande produktivitetsutveckling (såväl i Sverige som i många andra länder). En brist som också identifierats är att det faktiskt saknas pågående forskning kring produktivitetsmätning i byggandet i Sverige, något som har initierat detta projekt. Syftet var att visa på olika produktivitetsmått för framdriften av delprocesser i ett byggprojekt, men även jämförelser av dessa utifrån olika perspektiv såsom byggdel, byggnad och projekt. Syftet var inte att mäta och jämföra produktiviteten i/mellan de olika företagen utan att identifiera formella och informella nyckeltal och indikatorer förproduktivitet inom områdena som säkerhet, kund, leverans, ekonomi och kvalitet. En bärande del i projekt var inventeringen av produktivitetsmått som genomfördes genom intervjuer med personer på olika nivåer med tydlig bas i företagens produktion. Totalt genomfördes 15 intervjuerna med 3 personer/roller (Företagsledning, Avdelningschef ochPlatschef) på de 5 företag som deltog i projektet. Underlaget har vidareutvecklats genom diskussioner i referensgruppens. I rapporten presenteras mer än 40 olika produktivitetsrelaterade mätetal som identifierats under intervjuerna. De identifierade måtten baseras på de kvantitativa eller kvalitativa uppföljningarna som plastledningen i varierande grad utför, och kan delas in enligt kategorierna kostnad, tid, resurser, kvalitet, arbetsmiljö och kultur. För att få en större nytta samt möjliggöra en värdeskapande användning av produktivitetsmått, såsom görs i andra industrier, presenteras ett ramverk och system för mätningarna, som exemplifierats. I ett första steg föreslår vi användandet av de identifierade måtten satt i ramverksstrukturen. I ett andra steg för att byggföretag kontinuerligt och strukturerat ska förbättra produktiviteten föreslår vi att måtten behöver placeras i ett prestationsmätningssystem (PMS). Genom att använda mätetal samt förstå relationen mellan mätetalen från olika delar kan resultat användas i erfarenhetsåterföringssyfte såväl för det enskilda projektet som högre upp i en organisation. Några slutsatser/observationer från projekt är: - Det är ingen brist på mått direkt eller indirekt relaterade till produktivitet men företagsgemensamma standar och system för koppling saknas. - Egenmätning och registrering av mätetal bland yrkesgrupper förkommer sällan, där rådande lönesystem och organisation (kombination av YA och UE) är en utmaning. - Systematisk återkoppling av mätetal för kunskapsöverföring mellan projekt saknas. - En utmaning och förslag till fortsatt arbete är att utveckla likare/korrelationsfaktorer för att möjliggöra jämförelse mellan projekt, företag och för kunskapsöverföring mellan projekt