The analyzing of process parameters effects on residual stress in the stereolitography made prototypes

In the past, during the design process which is the rising point of production technologies, considerable problems are faced, particularly when the new product is being released. Especially after the design is finished, discussing concretely the first outputs of this design and by observing the existent mistakes, making the necessary corrections become nearly impossible or this come out as a stage which cost very high amounts. As a result of experiencing high-level cost and loss of time during the product?s releasing process, competition chance among firms is removed. By means of ?Rapid Prototyping Technologies? that has been raised in recent years, time of product releasing is decreased and minimized the mistakes in this process so greeted us as a cost-reducing component of production technologies. Nowadays, these technologies are widely used by various firms for commercial purposes. In addition to these, ?residual stress? that have been occurred in the materials and effect physical-mechanic characteristics, are one of the basic subject of engineering. Even if, residual stresses generally appear as a parameter which affects mechanic characteristics negatively, in certain occasions, it turns into a particularly desirable condition. With the help of experimental studies, the relationship between some process parameters that are used at the moment of manufacturing and residual stresses formation is researched in the most well-known method of ?Rapid Prototype Technologies?- Stereolithography made prototype parts. Test specimens were produced from epoxy-based resins with 0.1 mm and 0.15 mm layer thickness. Also with changing the support structures of these specimens as a triangle and square; different prototypes were obtained. In the results of experiments, increased layer thickness, which used during the manufacturing of prototypes, decreases the compressive residual stresses. When the stress values change to the tensile, it is related to both layer thickness and support structures. When using a triangle support structure, if the layer thickness is increased, tensile residual stresses are also increased. However, when the support structure is a square; tensile residual stresses are decreased with increased layer thickness. If the high strength is desired in the constructions which are composed to compressive stress, the triangle support structures should be used. If the construction is composed to tensile stress, the square support structure should be used. Keywords: Rapid Prototyping, Sterelithography, Residual Stress, Layer Removal Method