<p>In order to accomplish that a construction is correctly built, it is critical to obtain a well functioning control mechanism throughout the project. The way to enable this is not by having an independent inspector constantly at your side. Today it is praxis to use check lists and have people responsible of quality to make sure that these are followed. This is where discretionary inspections play their part. These among others are documents needed to com-plete the check list. Documented discretionary inspections are based on a control mechanism that allows the entrepreneurs to, in their own organizations, self check the performed task, and by that ensure that the quality of each task is executed in a satisfying way. Due to the fact that most projects today are suffering by lack of time during construction, it is most likely to presume that the discretionary inspections can fall out of the priority, be performed in an unsatisfying way or not be performed at all.</p><p>However, experience from construction business tells us that calculated energy consumption often differs from the actual, once the building is completed. This anomaly strikes hardest to apartment blocks and therefore we intend to find a connection between poorly executed dis-cretionary inspections and high energy usage. Discretionary inspections are used by most contractors in the construction business to ensure that the work in progress always serves en-vironmental lines of thoughts.</p><p>During the progress in our writing we have achieved a good insight in routines and how the business works, for good and for bad. The report finishes with a discussion considering the overall concept of discretionary inspections, how to improve them and potential ways of supporting the concept in the future.</p>

No description available.

<p>Abstract</p><p>My task was to prepare the already designed heating list “Stayhot” for manufacturing.</p><p>I started with drawing the whole list in the CAD-program. It became obvious that some of the designed components had to be changed to work in practice.</p><p>A turnable reflector couldn’t be combined with the isolation. The suggested light emitting diodes wouldn’t give enough light, so I cut them out and the problem with light remains to be solved. The old grating had many rods and I changed that to a grating with fewer rods to make it easier to clean. The hanging-up of the grating was also changed.</p><p>The lower ceasing was changed to be closed towards the reflector to avoid filth and damp.</p><p>The reflector had a different shape. From having been square it became oval to follow the shape of the above ceasing and have a more even isolation. It also opens up to the possibility to use two heating elements. The heating-source should have been changed to be warmer, but as the new elements didn’t come until my work was almost finished, I couldn’t use it.</p>

<p>Bakgrunden till examensarbetet är att det finns ett behov av att höja utnyttjandegraden i stans- och lasermaskiner hos Lars Höglund AB. Anledningen till att utnyttjandegraden behöver höjas är att företaget vill bli mera lönsamt och mera konkurrenskraftigt.</p><p>Uppgiften har varit att mäta utnyttjandegraden, göra en probleminventering och ta fram förslag på åtgärder som kan lösa de problem som kom fram i probleminventeringen.</p><p>Vid probleminventeringen visade det sig att det går att höja utnyttjandegraden genom att bl.a. göra en ställtidsreducering, skapa ordning och reda, samt att förebygga flaskhalsar.</p><p>5S är en metod som har använts för att ta fram förbättringsåtgärderna. Genom att följa denna metod, samt att göra några nya investeringar i företaget, ser det ut som att målet i detta arbete ska kunna uppnås.</p>

<p> </p><p>På ABB i Ludvika tillverkar man en mängd produkter för högspänningsanläggningar. En av dessa produkter är ventilavledare. Ventilavledaren är en säkerhetsapparat som ska skydda övrig utrustning mot förekommande överspänningar. Ventilavledarna som tillverkas i Ludvika är gjorda för system från 52kV upp till 800kV, vilket är den högsta spänningen som används i världen idag. Idag finns två varianter av ventilavledare en med porslinisolant och en med polymerisolant. På ABB ser man att kunderna mer och mer eftersträvar polymeravledare.</p><p>Polymeravledare har p.g.a. mekaniska begränsningar inte kunnat användas i system med högre spänning än ca. 245kV. För att kunna erbjuda polymeravledare för högre spänningar har en ny produkt tagits fram. Den nya produkten kallas <em>PEXLIM Stark. </em></p><p>Med den nya produkten innebär en mängd processer som måste arbetas fram. En sådan process är slutmontaget där man monterar de sista detaljerna.</p><p>Detta arbete har gjorts för att se vilka problem som kan uppstå vid slutmontaget och hur man löser dessa på bästa sätt.</p><p> </p><p> </p> / <p> </p><p>ABB has a big factory in Ludvika where many kinds of apparatus for high voltage systems are manufactured. Among the products are surge arresters, which are used to protect other equipments in power systems against all type of transient overvoltages. The arresters manufactured in Ludvika are for voltage systems from around 52kV up to 800kV which is the highest system voltage level in the world so far. The active elements in the arresters are blocks of ZnO material. The arresters are manufactured utilizing two types of enclosures, porcelains and polymer. Due to the good response from the customers more and more arresters are manufactured with polymer housings but so far the mechanical strength has prevented polymer designs for higher voltages than approximately 245kV. In a new project, therefore, a polymer housed arrester with higher mechanical strength will be developed. The working name for the new product is <em>PEXLIM Strong. </em>Among all the problems which have to be solved during the development of the new product is also how the final assembly of the product shall be performed. In this report, as part of a Bachelor of Science in Machine Engineering, the problems are analyzed and different solutions to obtain an efficient final assembly of the new product are suggested.</p><p> </p><p> </p>

<h2>Abstract</h2><p>At the plant of Outokumpu Stainless Tubular Products AB in Molkom a wide range of butt weld fittings are produced. These are aimed mainly for the process industries and one of the products are ninety degree bend elbows in various dimensions. The elbows are made from stainless sheet metal and when formed to a tube they need to be welded along its inner radius. This is made by a pick and place type industrial robot working in a closed compartment. The assignment given by Outokumpu aims to investigate and suggest a new concept for a more reliable manufacturing process within the work cell.</p><p> </p><p>The cell consists of five main areas chronologically listed as passed by the elbow:</p><p>·          Automated, vibrating conveyor.·          Fixture with the purpose to serve the robot with one elbow at a time, placed in the correct position.·          Industrial robot to pick up the elbow and drag it along the welding head.·          TIG inverter with a stationary welding head·          A hydraulic press with a template of the final shape of the elbow corrects flaws. Almost every problem in the cell and defects on the products coming out of it can be traced back to the fixture and in some cases also to the robots pick up tooling. The focus of the task was therefore put mainly on those two areas. As the work proceeded Outokumpu chose to develop a new tool for the robot themselves which they did with good results. I chose to incorporate it into my study and change focus to the fixture instead.</p><p> </p><p>The problems and possible causes to them were identified and discussed with my tutor:</p><ul><li>The elbows fall incorrectly into or beside of the fixture.  <ul><li>Fixtures are old and worn down.</li><li>The elbows path between conveyor and fixture are somewhat out of control</li><li>The smaller dimensions have room enough to slip past the fixture. <ul><li>Edges to be welded are to far from each other or badly shaped</li></ul></li></ul></li><li>Commissioning time, some start up steps is more complex then they need to be. <ul><li>Some of the setting possibilities in the working cell are unnecessary and can be fixed instead.</li><li>The positions of pick up and welding head are not really fixed in the robot software, these are reprogrammed every time elbow size are changed.</li></ul></li></ul><p>·          Various errors at weldingo    Robot managed to pick incorrectly placed elbow</p><p> </p><p>Proposals to solve the above specified problems:</p><ul><li>All parts in contact with the elbows are to be made of harden able steel. A suitable one is C45E which can be casehardened to about 700HV.</li><li>On the outer edge of the conveyer a support are placed to prevent excessive wear.</li><li>The fixture is partially redesigned with a support to control the elbows path better.</li><li>Guide arms with dual purpose are added. First they guide the elbow into the fixture and secondly they turn it to the correct angle towards the robot.</li><li>Pins are used along with quick lock clamps to obtain faster and easier commissioning.</li><li>The pick and place tool developed by Outokumpu are used.</li></ul>

Cellular Manufacturing Systems (CMS) have claimed many advantages over traditional job shop processes. Some of the advantages reported by several users of CMS are reduction in throughput time, reduction in WIP inventory, improvement in product quality, faster response time to customer orders, shorter move distances, increase in manufacturing flexibility, and greater job satisfaction. In its implementation, CMS organizes a production floor into manufacturing cells. Hence, the important issue that needs to be addressed first is the cell formation (CF) problem. CF deals with the identification of part families, machine groups, and allocation of part families and machine groups to cells or vice versa. In the past, most studies in CF have assumed that the location of a cell is known a priori and a unique route exists between two cells. However, in an actual manufacturing environment, alternative locations are available for locating each cell. Similarly, when the capacity of the material handler being used is limited, alternative routes may have to be used to move part loads between two cells. In this research, the issues dealing with alternative cell locations and alternative routes of material handling equipment are investigated. In addition, several other important factors common to CF are also considered. These include machine capacity limitations, batches of part demands, non-consecutive operations of parts, and maximum number of machines assigned to a cell. A mathematical model is first formulated to represent the research problem. The model is a binary and general integer non-linear programming model, and it belongs to the class of NP-hard problem. Therefore, a higher level heuristic algorithm, based on the concept known as tabu search, is developed to efficiently solve the problems with industry merit. Incorporating the features associated with the tabu search, resulted in developing six different versions of the heuristic solution algorithm. The six heuristics are tested on twenty small problems, and the quality of their solutions is evaluated by investing significant effort to find their optimal solutions. The evaluation shows that the heuristics are highly effective. The solutions obtained from the heuristics have average percentage deviation of less than 3% from the optimal solutions. The heuristics are also tested on their performances with medium and large problems. By using a statistical experiment that is based on randomized block design, the performance of the six heuristics is compared. Three different problem structures, ranging from 4 parts to 30 parts and from 3 locations to 9 locations are used in the experimentation. The experiment reveals that in general, the tabu search based-heuristic using fixed tabu list size and long-term memory based on minimal frequency strategy is preferred to other heuristics as the problem size increases. / Graduation date: 2000

Cellular Manufacturing Systems (CMS) have provided significant increase in manufacturing productivity over the last two decades. This has been achieved because CMS can overcome the problems due to frequent setups, high in-process inventories, long throughput times and complex planning and coordination commonly associated with a batch-type manufacturing operation. The underlying concept of CMS is the grouping of parts into part families and the machines that process these parts into machine cells in order to achieve manufacturing efficiencies. Creating machine cells which can perform all operations of a part without requiring the part to visit one or more cells other than its own is hard to achieve, if not impossible. Hence, in the design of CMS, one tries to minimize the material handling costs incurred due to the movements of parts to other cells. Duplication of "bottleneck" machines that process parts assigned to other cells into the appropriate cells and subcontracting of "bottleneck" parts that require one or more operation on machines assigned to another cell are two important methods utilized to form disaggregated manufacturing cells in order to minimize the material handling costs. A mathematical model and a solution algorithm is developed to simultaneously deal with the issues of duplicating bottleneck machines and subcontracting bottleneck parts. Because there is a cost associated with the process of duplication and subcontracting, the benefits attained are analyzed for different budgetary constraints encountered by a firm. The algorithm was tested on three different problem structures for a range of budgetary restrictions. The results obtained show that the algorithm could be used by the industry to solve problems encountered in the design of CMS. / Graduation date: 1994

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 47-52). Also available in electronic version.

Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 86-90).