Investigation and modeling of mould surfaces and the alterations during the process on the basis of geometrical product specifications

INVESTIGATION AND MODELING OF MOULD SURFACES AND THEALTERATIONS DURING THE PROCESS ON THE BASIS OF GEOMETRICALPRODUCT SPECIFICATIONSAnıl NOMAK AKDOĞANMechanical Engineering, Ph.D. ThesisSurface Roughness is a suitability state that must be pursued closely for forming componentswhich work under severe conditions. It is a fact that forming component?s surface roughnessaffects the product?s nature that is being formed. In this scientific perspective, monitoring thesurface roughness diversities that the moulds used for manufacturing the glass product encounterduring manufacturing and the effects of these diversities on mould performance and glass productsuitability has a significant importance. Surface Roughness is an important relevance conditionhas to be evaluated in the frame of ?Geometric Product Specifications? standards like form,dimension, direction and location tolerances.In this study, test specimens consist of DIN 1.2787 stainless steel that is widely used inmanufacturing glass household goods, DIN 1.2080 stainless steel specimen and the specimen ofthe same material that was surface boronized. In laboratory conditions, these specimens aresubjected to glass that was in forming temperature and the changing surface roughnessparameters have been monitored with precise measuring techniques. At the end of thecomparison and the evaluation processes, using the boronized 1.2080 steel as a glassmanufacturing mould, it was observed that some of the surface roughness parameters were higherthan the other specimens. Contrary to this, in some parameters, affirmative values that increaseperformance have been monitored. The data that were obtained have been evaluated by usingSPSS 13.0 (Statistical Package for Social Science) and a mathematical model that gives Ra(Arithmetical Average Roughness) parameter against some thermal specifications of material andN (number of cycling) value has been established.In this study also, the effect of the stresses and the stress periods on surface roughness areproved. A heat transfer model is developed which identifies a thermomechanical cycling andagree with the tests. That model could apply the materials which are exposed to the similareffects. The created stress formula has the ?Gaussian Probability Function? solution in it. Withthat model is it possible to find the stresses at any point of any material which subjected to anytemperature degree.Keywords: Surface roughness, Geometric Product Specifications (GPS), precision measurement,glass forming moulds, thermal cycling.JURY:Prof. Dr. M. Numan DURAKBAŞA (Supervisor) Date:03.03.2006Prof. Dr. Murat DİNÇMEN Page: 217Prof. Dr. Nurullah GÜLTEKİNProf. Dr. Talha DİNİBÜTÜNProf. Dr. Bülent DURMUŞOĞLU