Process planning is a task comprising a broad range of activities to design and develop an appropriate manufacturing process for producing a part. Interpretation of the part design, selection of manufacturing processes, definition of operations, operation sequences, machining datums, geometrical dimensions and tolerances are some common activities associated with the task. Process planning is also “the link between product design and manufacturing” with the supplementary commission to support design of competitive products. Process planning is of a complex and dynamic nature, often managed by a skilled person with few, or no, explicit methods to solve the task. The work is heuristic and the result is depending on personal experiences and decisions. Since decades, there have been plenty of attempts to develop systems for computer-aided process planning (CAPP). CAPP is still awaiting its breakthrough and one reason is the gap between the functionality of the CAPP systems and the industrial process planning practice. This thesis has an all-embracing aim of finding methods that cover essential activities for process planning, including abilities to predict the outcome of a proposed manufacturing process. This is realised by gathering supporting methods suitable to manage both qualitative and quantitative characterisation and analyses of a manufacturing process. The production research community has requested systematisation and deeper understanding of industrial process planning. This thesis contributes with a flow chart describing the process planning process (PPP), in consequence of the methodological studies. The flow chart includes process planning activities and information flows between these activities. The research has been performed in an industrial environment for high volume manufacturing of gear parts. Though gear manufacturing has many distinctive features, the methods and results presented in this thesis are generally applicable to precision manufacturing of many kinds of mechanical parts. / <p>QC 20140522</p>

Målet med detta examensarbete har varit att utvärdera ett simuleringsverktyg för toleranskedjeanalyser i 1D, följt av en jämförelse med dagens metod att beräkna toleranskedjor i 1D med kalkylark i Excel. Simuleringsverktyget heter EZtol och har funnits sedan ett och ett halvt år tillbaka. Examensarbetet utfördes på uppdrag från Scania CV AB, som ville undersöka om mjukvaran kan ersätta den nuvarande metoden. Examensarbetet utfördes under 10 veckor och delades upp i tre huvudområden: Upplärning i form av webkurs och internkurs på Scania, simulering av olika toleranskedjor i mjukvaran samtidigt som beräkningar i kalkylark gjordes och till sist rapportskrivning. Rapporten är uppdelad i sex kapitel. I det första kapitlet beskrivs bakgrunden till problemet, mål och syfte. Det andra kapitlet redogör för nuläget som påvisar att det finns ett visst behov av en mjukvara. Konstruktörer intervjuades för att få en bild över vilka behov som inte uppfylldes i kalkylarket. Dessa visade sig främst sig vara grafisk visualisering och bidragslista över toleranser (en lista som visar vilka toleranser som påverkar utfallet mest). I det tredje kapitlet beskrivs teorierna som använts som grund till arbetet. Teorierna är Användarguiden i EZtol, Grundläggande om toleranser, toleranskedjor, Simulering och CATIA V5. I kapitel fyra beskrivs genomförandet vilket till största del bestått av upplärning samt simulering i mjukvaran. Det femte kapitlet redogör resultatet vilket presenteras i form av för- och nackdelar. De främsta fördelarna har visat sig vara grafisk visualisering av toleranskedjor samt bidragslista över toleranser. Dock visade det sig att den främsta nackdelen var att mjukvaran inte klarar av att hantera långa och mer komplicerade toleranskedjor, vilket har lett till slutsatsen att mjukvaran inte rekommenderas till Scania i dagsläget. Scanias krav uppfylls inte då mjukvaran inte kan hantera företagets alla toleranskedjor. Men eftersom konceptet kring EZtol är intressant bedöms ändå mjukvaran ha potential att passa in på Scania om några år. En rekommendation är därför att simuleringsmjukvaran bör utvärderas om på nytt i framtiden. / The aim with this thesis work has been to evaluate a simulation tool for 1D-analysis of tolerancechains, followed by a comparison with the current method to calculate tolerance-chains in 1D with spreadsheets in Excel. The simulation tool is named EZtol and has existed for one and a half year. The thesis work has been carried out on assignment from Scania CV AB. The company wanted us to evaluate if the software could replace the current method. The thesis work has been carried out during 10 weeks and was divided in three main sections: Education in terms of a web-course and internal course, simulation of different tolerance-chains in the software as well as calculations in the spreadsheet and finally make a scientific report based on the thesis work. The essay is divided in six chapters. The first chapter describes the background, aim and purpose of the thesis work. The second chapter describes how the situation of tolerance-chain calculations looks today, which has shown that there is a certain need of a software. The designers were interviewed so that the thesis workers could establish what the spreadsheet could not fulfill, which was graphic visualization of tolerance-chains and also a list with the contributions of all tolerances. The third chapter describes the theories that have been used for this thesis work. The theories are Tutorial in EZtol, Fundamental facts about tolerances and tolerance‐chains and Simulation and CATIA V5. In the fifth chapter the results of this thesis work are featured, which are presented as advantages and disadvantages. The main advantages with the software are graphic visualization of the tolerance-chains as well as a list that shows the contributions of every tolerance. The primary disadvantage though is that the software cannot handle long and more complicated tolerance-chains. Which has led to the conclusion that the thesis workers do not recommend the software to Scania at present time. Scanias requirements cannot be fulfilled with the software because it has not been able to handle all of Scanias tolerance-chains. But since the EZtol concept is good the software is estimated to potentially fulfill Scanias needs in a few years. A recommendation is that the software ought to be reexamined in the future.