In this research we consider two different approaches for microfabricating physical templates to be used in template directed colloidal self-assembly experiments. Fabrication of templates, usable with confocal microscopy, forms an essential part of observation and analysis of template directed colloidal self-assembly studies. We use existing laboratory based microfabrication methods for patterning thin glass coverslips and polymeric films. These templates when used for directing colloidal self-assembly along with confocal microscopy analysis provide us with relevant information on the effect of confined geometries of the template on particle packing and order. The first method of template fabrication involves ultraviolet photolithography, thin film deposition, and glass micro machining. Various stages of the process were optimized while selecting reactive ion etch (RIE) and nickel etch mask with a suitable etch recipe for microfabrication of patterns on thin multi-component glass coverslips. Pattern dimensions were shown to be nearly commensurate with patterns on the microfiche, which was used as a field mask. In another approach, mechanical machining for fabricating polymeric templates was attempted on poly(methyl methacrylate) films spin coated on thin glass cover slips. The mechanical machining was implemented using computer numerical control (CNC) machines with the pattern dimensions in the range of 50 Mu m-150 Mu m. The glass and polymeric templates were used in template directed colloidal self-assembly experiments us ing polystyrene or silica particles. Confocal microscopy was used to obtain images of particle packing in template geometries. Imaging of the particles confined in the template geometries show increased particle concentration along pattern walls and corners. Inherent pattern irregularities and roughness possibly resulted in limited order in particle. Using a simple fortran program, image stack generated from confocal microscopy is used for obtaining images of particle packing in four different view planes which includes top, side, cross sectional and diagonal view of the image stack. The results from this research show the application of simple microfabrication processes for creating physical templates for template directed colloidal self-assembly. Confocal microscopy imaging combined with fortran image processing program can provide images of particle packing in different view planes. These images of the particles confined in various pattern geometries illustrate greater possibility of packing order in straight and regular pattern geometries or profiles.

This dissertation focuses on developing algorithms that generate tool paths for free-form surfaces based on accuracy of desired manufactured part. A manufacturing part is represented by mathematical curves and surfaces. Using the mathematical representation of the manufacturing part, we generate reliable and near optimal tool paths as well as cutter location (CL) data file for postprocessing. This algorithm includes two components. First is the forward-step function which determines maximum distance called forward- step between two cutter contact (CC) points with given tolerance. This function is independent of the surface type and is applicable to all continuous parametric surfaces that are twice differentiable. The second component is the side-step function which determines maximum distance called side-step between two adjacent tool paths with a given scallop height. This algorithm reduces manufacturing and computing time as well as the CC points while keeping the given tolerance and scallop height in the tool paths. Several parts, for which the CC points are generated using the proposed algorithm, are machined using a three axes milling machine. As part of the validation process, the tool paths generated during machining are analyzed to compare the machined part and the desired part.

Product miniaturization is a long-term trend. Mechanical micro-machining is a suitable technique for manufacturing of microstructures characterized by cheap equipments, less working time, and possible complex geometry. For the requirements for high precision manufacture, the use of minimum/minimal quantity lubrication (MQL) is a good strategy for micro-machining due to long tool life and high product accuracy. This study presents an experimental investigation of the MQL in micro milling. The tool wear, surface roughness, and burr formation are observed at different feeds (1 £gm/rev, 1.5 £gm/rev, and 2 £gm/rev) and cutting speeds ( 37.7 m/min, 56.55 m/min, and 75.4 m/min) under dry and MQL cutting. Unlike conventional milling, greater tool wear is observed at lower feeds. Compared with the same cutting condition for dry cutting (feed 2 £gm/rev, cutting speed 56.55 m/min), MQL can reduce the tool wear about 56%. In terms of the consumption of the cutting fluid, oil flow rate of 1.88 ml/h is sufficient for reducing the tool wear in micro milling. According to the experimental results, deterioration of surface finish and burr formation are closely related to the tool wear. The use of MQL, not only reduces the tool wear, but also diminishes the deterioration of surface finish (the improvement of Ra is at least 0.6 £gm) and the burr formation.

In this study, an electrolytic micro-machining tester is employed to investigate the effects of supply voltage,electrode gap and initial machining position on the geometry of the tungsten needle. The tungsten needle to be electrolyzed is dipped in an aqueous electrolyte of 2wt % sodium hydroxide as the anode, and the stainless steel needle with a diameter of 50 £gm as the cathode(tool electrode), and the electrode gap is set to be 30 £gm.Morever,the tungsten needle can be allowed to be fixed or in the reciprocating motion. Experimental results show that when the tip diameter of stainless steel needle is less than 50 £gm, a great quantity of current density and power are generated to cause the temperature failure of the tool electrode. At a certain gap between the electrodes, the electric field is focused on the narrow range to improve its processing efficiency. Under the higher supply voltage condition, it is difficult to control the size because the diameter of tungsten rod is reduced very quickly. Under the lower supply voltage condition, the diameter of tungsten rod can be processed to smaller sizes, but it takes a long time. Therefore, in the beginning of the experiment, the tungsten rod is electrolyzed under a higher voltage to the small size, and then the supply vltage is switched to lower value to conduct the electrolysis process. Consequently, a finer and more even tungsten needle can be obtained. Experimental results show that a more even tungsten needle with the length of 600 £gm and the diameter of 4 £gm can be manufactured.

<p>The objective of this thesis is to find and develop methods that enhance and support the creation of evolvable master process plans with possibilities to challenge productivity and meet changing design requirements. The condition for achieving this is primarily that both the fundamental thinking and the results behind a process plan can be described. How should this be done?</p><p>The focus is laid on process planning of gear transmission parts for heavy vehicles like trucks and coaches.</p><p>Process planning is the activity where design and manufacturing are brought together with the common target to achieve both a competitive product and production process. There are many factors that influence the process planner when a new product or process shall be introduced for production. Process planning is, in most cases, performed by an experienced, skilled person but without any defined methodology or way of working. Much of the process planning is based on the retrieval of solutions already used.</p><p>Much research effort has been devoted to developing systems for computer-aided process planning (CAPP). Yet CAPP systems have not been accepted and spread over a wide front within the manufacturing industry, much because of the functional incompleteness combined with the difficulties of adopting knowledge and changing requests.</p><p>A method for systematic process planning is proposed as a way to perform and describe the procedure of creating a process plan. The method facilitates the interpretation and understanding of the plan, not only immediately for the process planner responsible, but also for designers, engineers, researchers and other interest groups involved in a manufacturing process.</p><p>In the last chapter is a case study regarding manufacturing of a bevel gear pinion presented to exemplify use of the proposed method for systematic process planning.</p> / KUGG

<p>Detta examensarbete har utförts vid Linköpings universitet i samarbete med Scania Transmission i Södertälje och behandlar kravsättning av ytstrukturer samt processer för hårdbearbetning av kugghjul och axlar. Aktuella artikelritningar innefattar endast krav för Ra-värde, den aritmetiska medelavvikelsen för ytjämnhetsprofilen (R-profilen). Förslag på nya parametrar enligt av Scania tillämpade SS-EN ISO standards har tagits fram, detta för att ge en noggrannare beskrivning av vilken ytstruktur som skall uppnås. Resultatet är generellt tillämpningsbart men fokuseras mot kugghjulens hål, plan och diametrar. Vidare presenteras en jämförelse mellan metoder så att transmissionsverkstäderna kan tillverka kugghjul/axlar på ett kostnadseffektivare sätt. Arbetet grundas på en litteraturstudie av handböcker och standards kompletterat med kartläggning av nuläget genom insamling av mätdata. En omvärldsanalys och några bearbetningsprover med hårdsvarvning har också utförts. Till skillnad från nuläget föreslås en övergång från att ange Ra-värde på ritningarna till att ange en övre gräns för Rz-värde som en begränsning av amplituden. Ytor i relativ rörelse och ytor som ingår i pressförband föreslås kompletteras med en undre gräns för Rz-värde samt en undre gräns för relativ bärighet. Med införandet av ett bärighetskrav ges även en specifikation för profilens fördelning. Angivelse av bearbetningsmetod och eventuellt bearbetningsmönster föreslås att anges i klartext på ritningen då parametrar som beskriver karakteristiska drag för olika bearbetningsmetoder visat sig väldigt variationsbenägna i nulägesanalysen. Jämförelse av hårdbearbetningsmetoder har visat att det i kombinationsmaskiner, hårdsvarvning och slipning, vore intressant att enbart hårdsvarva kugghjulens glidlagerytor, något som enligt bearbetningsprover och omvärldsanalys verkar rimligt. Detta bör efter godkännda riggprover anammas som ett första optimeringssteg. Fler intressanta koncept för framtida bearbetningsalternativ finns att studera i rapportens resultat och diskussionskapitel.</p> / <p>This master thesis report was performed at Linköpings University in cooperation with Scania Transmission in Södertälje and deals with specification of surface textures and processes for hard part machining of cogwheels and shafts. Present blueprints only include requirements for Ra-values, arithmetic mean deviation of the roughness profile (R-profile). Suggestions of new parameters according to SS-EN ISO standards used by Scania have been compiled with the aim of providing a more accurate description of the surface texture that is to be achieved. The result can be applied in general but are focused towards holes of cogwheels, planes and diameters. Furthermore a comparison between different methods is presented so that the transmission workshops can manufacture cogwheels and shafts in a costefficient manner. The work is based on a comparative literature study of handbooks and standards with complementary documentation of the present situation through collecting of measurements. A reference analysis and a few manufacturing tests of hard turning have also been performed. In difference from the present situation a transition from providing Ra-values on the blueprints to specify an upper limit for Rz-value to restrict the amplitude is recommended. Surfaces in relative motion and surfaces in heavy force fit are suggested to be complemented with a lower limit for Rz-values and a lower limit for relative material ratio. With an introduction of material ratio requirements the profiles distribution are also specified. Denunciation of manufacturing method and surface lay if any is suggested to be stated en clair on the blueprint being so that parameters describing characteristic features for different manufacturing methods have shown a wide range of distribution in the present state analysis. Comparison of hard part machining methods have shown that in combination machines, hard turning and grinding, solely hard turning of the cogwheels slide bearing surfaces would be interesting, which also seems plausible due to manufacturing samples and the reference analysis. After approved rigg tests this method can be adopted as a first step of optimization. More interesting concepts for future manufacturing alternatives are provided in the reports result and discussion chapters.</p>

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 230-235). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 230-235). Also available on the Internet.

Detta examensarbete har utförts vid Linköpings universitet i samarbete med Scania Transmission i Södertälje och behandlar kravsättning av ytstrukturer samt processer för hårdbearbetning av kugghjul och axlar. Aktuella artikelritningar innefattar endast krav för Ra-värde, den aritmetiska medelavvikelsen för ytjämnhetsprofilen (R-profilen). Förslag på nya parametrar enligt av Scania tillämpade SS-EN ISO standards har tagits fram, detta för att ge en noggrannare beskrivning av vilken ytstruktur som skall uppnås. Resultatet är generellt tillämpningsbart men fokuseras mot kugghjulens hål, plan och diametrar. Vidare presenteras en jämförelse mellan metoder så att transmissionsverkstäderna kan tillverka kugghjul/axlar på ett kostnadseffektivare sätt. Arbetet grundas på en litteraturstudie av handböcker och standards kompletterat med kartläggning av nuläget genom insamling av mätdata. En omvärldsanalys och några bearbetningsprover med hårdsvarvning har också utförts. Till skillnad från nuläget föreslås en övergång från att ange Ra-värde på ritningarna till att ange en övre gräns för Rz-värde som en begränsning av amplituden. Ytor i relativ rörelse och ytor som ingår i pressförband föreslås kompletteras med en undre gräns för Rz-värde samt en undre gräns för relativ bärighet. Med införandet av ett bärighetskrav ges även en specifikation för profilens fördelning. Angivelse av bearbetningsmetod och eventuellt bearbetningsmönster föreslås att anges i klartext på ritningen då parametrar som beskriver karakteristiska drag för olika bearbetningsmetoder visat sig väldigt variationsbenägna i nulägesanalysen. Jämförelse av hårdbearbetningsmetoder har visat att det i kombinationsmaskiner, hårdsvarvning och slipning, vore intressant att enbart hårdsvarva kugghjulens glidlagerytor, något som enligt bearbetningsprover och omvärldsanalys verkar rimligt. Detta bör efter godkännda riggprover anammas som ett första optimeringssteg. Fler intressanta koncept för framtida bearbetningsalternativ finns att studera i rapportens resultat och diskussionskapitel. / This master thesis report was performed at Linköpings University in cooperation with Scania Transmission in Södertälje and deals with specification of surface textures and processes for hard part machining of cogwheels and shafts. Present blueprints only include requirements for Ra-values, arithmetic mean deviation of the roughness profile (R-profile). Suggestions of new parameters according to SS-EN ISO standards used by Scania have been compiled with the aim of providing a more accurate description of the surface texture that is to be achieved. The result can be applied in general but are focused towards holes of cogwheels, planes and diameters. Furthermore a comparison between different methods is presented so that the transmission workshops can manufacture cogwheels and shafts in a costefficient manner. The work is based on a comparative literature study of handbooks and standards with complementary documentation of the present situation through collecting of measurements. A reference analysis and a few manufacturing tests of hard turning have also been performed. In difference from the present situation a transition from providing Ra-values on the blueprints to specify an upper limit for Rz-value to restrict the amplitude is recommended. Surfaces in relative motion and surfaces in heavy force fit are suggested to be complemented with a lower limit for Rz-values and a lower limit for relative material ratio. With an introduction of material ratio requirements the profiles distribution are also specified. Denunciation of manufacturing method and surface lay if any is suggested to be stated en clair on the blueprint being so that parameters describing characteristic features for different manufacturing methods have shown a wide range of distribution in the present state analysis. Comparison of hard part machining methods have shown that in combination machines, hard turning and grinding, solely hard turning of the cogwheels slide bearing surfaces would be interesting, which also seems plausible due to manufacturing samples and the reference analysis. After approved rigg tests this method can be adopted as a first step of optimization. More interesting concepts for future manufacturing alternatives are provided in the reports result and discussion chapters.

Particleboard (PB) is a widely used panel material because of its physical properties and low cost. Unfortunately, cutting can degrade its surface creating rejects and increasing manufacturing costs. A major challenge is PB’s internal variability. Different particle and glue bond strength combinations can sometimes create high quality surfaces in one area and defects such as edge chipping in nearby areas. This research examines methods of improving surface quality by examining PB characteristics and their interactions with the cutting tool. It also develops an analytical model and software tool that allows the effects of these factors to be simulated, thereby giving practical guidance and reducing the need for costly experiments. When PB is cut and the glue bond strength is weaker than the particle strength, particles are pulled out, leading to surface defects. When instead the glue bond strength is stronger than the particle strength, particles are smoothly cut, leading to a high quality surface. PB is modeled as a matrix of particles each with stochastically assigned material and glue bond strengths. The PB model is layered allowing particles to be misaligned. Voids are modeled as missing particles. PB cutting is modeled in three zones. In the finished material and tool tip zones, particles are compressed elastically and then crushed at constant stress. After failure, chip formation occurs in the chip formation zone. At large rake angles, the chip is modeled as a transversely loaded beam that can fail by cleavage at its base or tensile failure on its surface. At small rake angles, the chip is modeled as the resultant force acting on the plane from the tool tip through to the panel surface. Experimental and simulation results show that cutting forces increase with depth of cut, glue content and particle strength. They decrease with rake angle. Glue bond strength can be increased to the equivalent particle strength through the selection of particle geometry and the subsequent increased glue bond efficiency, which increases the cut surface quality without the need for additional glue. Minimizing the size and frequency of voids and using larger rake angles can also increase surface quality.