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 Na bosanskom jeziku  Non-proportional scaling of metal casting moulds

Project Title

Non-proportional scaling of metal casting moulds

Short Title


Project Coordinator University of Zenica, Mechanical Engineering Faculty
Project Partners Slovenian Tool Development Centre TECOS, Celje, Slovenia
Project Timeline 2012 - 2013
Financing Source Bilateral project BiH - Slovenia
Project Description

In order to compensate shrinkage in casting, it is common to transform the 3D CAD model of a tool by a certain percentage. These transformations include 3D scaling (up to 1,5% for cast metal) or external surface offset. Both methods are proportional and uniform in all three axes, and they are already included in a vast variety of CAD software packages. The shrinkage process, however, is not necessarily uniform, and some portions of a product can have different shrinkage ratio. Therefore, it is necessary to introduce the new CAD transformation technique: non-proportional 3D scaling. This research deals with estimation of 3D function that should be used to transform the 3D CAD model of a tool, in order to obtain the optimum result. The casting tool and sample castings will be measured on a coordinate measuring machine, and these measurement results will be used to estimate the shrinkage percentage needed for different parts of a CAD model. After 3D function is determined, an algorithm will be defined to enable implementation of this function into 3D modelling software, i.e. creation of casting tool which is nonproportionally scaled from the casting pattern. That would enable higher precision of castings, despite shrinkage phenomenon.
Although needs of metal and plastics-processing industry for casting tool design are high, only a few manufacturers in Bosnia and Herzegovina have their own tooling departments. Tools are mainly imported, and that reflects onto higher production costs, thus making Bosnian products less competitive in global market. This project represents a contribution in the development of tool making in terms of application of new technologies of development and design of casting tools. The partner institutions in this project will be Mechanical Engineering Faculty at the University of Zenica, and Slovenian Tool and Die Development Centre TECOS Celje. This project will engage young researchers - final year students at the Mechanical Engineering Faculty in Zenica, and they would have a chance to connect theoretical knowledge and skills with industrial praxis. The project will also be supported by industrial partner, foundry "Novi život" Zenica, which will make the tool prototypes and sample castings to be tested through this research.

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