Papers by Author: Mika Lohtander

Abstract: Changes taking place in project-based manufacturing emphasize the importance of agile manufacturing, product knowledge management and product lifecycle information. The paper describes dependencies between product definition and production strategy covering also other potential areas of research i.e. growth of industrial service business and development of manufacturing and supply networks. As an outcome it can be argued that more research is needed to align product lifecycle management in project-based manufacturing, as well as to cover the evolving information needs of internal and external stakeholders. Due to the increase of industrial services, also services should be included as a part of product definition; the extended product description introduces a new set of requirements that need to be taken into account as a part of product and production strategy definition.

Abstract: Engineering change management (ECM) affect to cost that are generated during the designing and manufacturing process. ECM also affects to the time how fast the product is on market. The changes have to be made quickly and the notifications of the changes have to reach the person who may need the information. Product Data Management (PDM) is the system which is not only storage place for the data; it is a tool which should make ECs faster and more effective. This paper deals with the techniques that are in use to handle the ECs with the help of PDM system.

Abstract: This work describes a fuzzy expert system for rough turning. In order to automate unmanned turning, safety of the process must be ensured. In addition, any quality requirements should be fulfilled and, within these constraints, productivity maximized. The traditional approach in adaptive control of machining is to keep a measured quantity, such as power, within acceptable limits. However, there have been some studies measuring distinct phenomena in machining and identifying “cutting states” based on the phenomena. By identifying cutting states corresponding to phenomena monitored by human experts, it is possible to construct an intelligent machining system emulating the decision making of a human expert. This paper concentrates on defining the requirements for the inference part of such of an intelligent machining system. This work concentrates on both functional requirements, such as capability to take into account specific cutting states. The existence of process monitoring subsystems which detect and measure the cutting phenomena is assumed. As a result, a Sugeno-type fuzzy control is suggested, and feasibility and the level of completeness of such a system are discussed and issues requiring further study are identified.

Abstract: This research explores how successfully melting and laser based additive manufacturing (LAM) process functions in the manufacture of fractal-like micro channel heat transfer devices. Different micro channels are studied worldwide and the studies at Lappeenranta University of Technology (LUT) aim to utilize micro channel geometries in heat transfer applications to solve cooling problems related to green technologies. Power electronics, micro-reactors, and fuel cell applications are a part of this development. Many of these technologies suffer from high, local heat fluxes. New energy production and vehicle systems can no longer be cooled only by air or water based liquid, because the growing power densities have reached the limits of air and water cooling. The goal of the work is to find an answer to the following question; what is the capability of the LAM process when manufacturing fractal like micro channels The study shows result of manufacturability tests of the micro-channels and gives recommendations for further study. Based on the manufacturing tests and literature findings, it can be stated that the used LAM process does not fully qualify for the manufacture of the micro channels in heat transfer devices at the moment. Process can be considered for manufacturing channels on a larger scale.

Abstract: In the today’s industry the sheet metal design plays a huge role, it has been said that almost the half of the designing is concentrating to sheet metals. But the lack of knowledge of the typical sheet metal aspects and basic rules of sheet metal designing, has led in to situation where more and more products are poor designed. This automatically leads to situation that the products are not manufacturing friendly. Designing time is shortening year after year, so the pressure to design the part as fast as possible is huge. Unfortunately all the design information and the design intent is processed and filtered to be fit for the Product Data Management (PDM) system. As the PDM was firstly designed to be used only for the storage base for the design drawings and other data; the feature-information and design intent is lost. This paper deals with two distinct yet interlinked themes. The first theme is the new requirements set for the new Product (Life-time) Information systems that can save the product information and design intent. And the second theme is the modern, light-weight and updatable product-services that allow the manufacturability to be ensured before product realization. With the help of novel product-service such as Design Manufacturing and Assembly (DFMA) for sheet metal industry designers will able to design in shorter time manufacture friendly sheet metal products.

Abstract: In this paper, we present different points of view to make the sheet metal and micro-wave product as manufacturing friendly as possible. Within DFM(A)-research (Design for Manufacturing and Assembly), engineering design and manufacturability of Micro-Wave (MW) and sheet metal products has been studied. Other aspects of DFM(A) have risen from novel material applications and the development of CAD (Computer Aided Design) environments. In this paper, practical examples are presented to show how to apply DFMA-rules to MW- and sheet metal components, in particular, and how to develop DFM(A)-rules for these purposes.