Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 27-40).

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xvi, 255 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Glenn S. Daehn, Dept. of Materials Science and Engineering. Includes bibliographical references (p. 201-202).

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 198-212). Available also in a digital version from Dissertation Abstracts.

Volvo Construction Equipment with headquarters in Eskilstuna is the world's oldest and one of the leading companies in the construction industry with products such articulated haulers, wheel loaders, excavators and skid steer loaders. The main purpose of this study is to create a tool for predicting the production cost of welded structures for the company's articulated haulers, which today is world leading on the market. To succeed, the study has been broken down in three problem areas in which the first one is to completely map out today's manufacturing process of the six basic components of the articulated hauler model A40 (A-Stay front, A-Stay rear, short and long rods and front and rear frame) for both manual and robotic welding. Account is taken to each weld in the manufacturing process and all costs incurred. Various types of welding measurements such as thread consumption for both manual and robotic welding, weld length for both manual and robotic welding is taken account to. The weld metal weight, arc time, robot degree length, deposition rate, price per meter, price per kilo and the total cost for each component has been measured and calculated. Next problem area starts from the identification of the manufacturing process and the purpose is to identify the largest cost culprits to lower manufacturing process costs and making the manufacturing process more efficient. As regards the third and final problem area on basis of the results from the two past problem areas regression is used to generate a mathematical formula that is used to predict the production of welded components for the company's articulated haulers. The final tool that is sought was created in form of a software by embedding the mathematical formula obtained from the regression. Now one can easily predict the production cost of welded structures by using the following tool. The only thing you need to do to predict any production cost of a welded structure is to enter the drawing welding weight, item weight, average welding length, proportion of butt weld percentage and the butt weld length for manual and robot welding. / Volvo Construction Equipment med huvudkontor i Eskilstuna är världens äldsta och en av världens ledande företag vad gäller anläggningsmaskiner som exempelvis dumprar, hjullastare, grävmaskiner och kompaktlastare. Syftet med detta arbete är att skapa ett verktyg för att kunna förutse produktionskostnaden för svetsade komponenter för företagets ramstyrda dumprar som idag är världsledande i sin klass. För att lyckas med projektet har man brutit ner syftet i tre problemområden där man först och främst kartlägger hela dagens tillverkningsprocess av de sex grundläggande delarna för dumpermodellen A40 (A-stag, Vågbalk, kort och långt stag samt fram och bakram) för både manuell och robot svetsning. Hänsyn tas till varje svets i tillverkningen och alla kostnader som uppstår. Man utför även olika typer av svetsmätningar som exempelvis trådförbrukning och total svetslängd för både manuell och robotsvetsning. Man beräknar även svetsgodsvikten, bågtidsfaktorn, robotgradlängden, insvetstalet, pris per meter, pris per kilo och totalkostnaden för varje objekt. Vid nästa steg utgår man från kartläggningen av tillverkningsprocessen och man identifierar de största kostnadsbovarna med syfte att sänka tillverkningskostnaderna och göra tillverkningen mer effektiv. Vad gäller tredje och sista steget med utgångspunkt från tidigare resultaten använder man regression för att generera en matematisk formel som man använder för att kunna förutse produktionskostnaden för svetsade komponenter för företagets ramstyrda dumprar. Det slutgiltiga verktyget som eftersöks skapades i form av en mjukvara för datorer genom att bädda in den matematiska formeln man erhöll från regressionen som bygger på resultaten av kartläggningarna. Nu kan man enkelt förutse produktionskostnaden av svetsade komponenter. Det enda man behöver göra för att förutsäga någon produktionskostnad av en svetsad komponent är att mata in ritningens svetsvikt, objektvikt, medelsvetslängd, andelen stumsvets i procent samt längden manuell och robot stum svets för den komponenten man vill förutsäga priset på. Nyckelord: Svetsgodsvikt, Svetsekonomi, Regression.

No description available.

No description available.

Contour laser transmission welding (LTW) is a technology that has potential for joining large and complicated thermoplastic parts. Thermal expansion is the primary driving force to bridge potential gaps at the weld. A comprehensive investigation into gap bridging was performed using experimental studies, finite element (FE) thermal-mechanical coupled modeling, and analytical analysis of the contour welding process for polycarbonate (PC), polyamide 6 (PA6) , and glass fibres reinforced polyamide 6 (PA6GF). The effects of material properties (carbon black level, glass fibres and crystallinity), process parameters (laser scan power, scan speed) and weld gap thickness on weld shear strength were assessed. The experimental study indicated that low concentration of laser absorbing pigment accompanied with high power laser scan improves gap bridging. Damage on the top surface of the laser-transparent part limited the allowable laser power that could be delivered onto the weld interface. Maximum gaps of 0.2, 0.4 and 0.25 mm were bridged in the experiment for the three types of polymers respectively. The thermal behavior of polymers in contour LTW was analyzed by the 3-D quasi-static thermal FE models. Thermal expansion into the gap was simulated by the simplified 2-D transient, thermal-mechanical coupled FE models. An analytical model describing laser beam transmission and absorption in light-scattering polymers was developed and applied in the FE simulation for PA6 and PA6GF. FE simulated results agree well with the experiment in contour welding with gap of PC and PA6. The optimum material and process parameters have been searched in the model to maximize gap bridging for PC. An analytical model has been developed to predict the temperature rise and the thermal expansion in high speed contour welding of amorphous polymers. The model indicates that the maximum temperature at weld increases linearly with the laser line energy and the laser absorption coefficient. Thermal expansion and hence gap bridging increases with laser line energy. Lower laser absorption coefficient allows higher laser scan energy to be delivered onto the weld interface so helps bridge larger gap. The predicted thermal expansions by the model agree well with the measured maximum gaps bridged for polycarbonate. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2009-09-24 22:24:11.734

No description available.

No description available.

No description available.