The purpose of the diploma work was the characterization of materials that can be 3D printed and afterwards used for investment casting. We wanted to find out the properties of three materials, polyvinyl alcohol or PVA, a photosensitive resin called Castable, and polylactic acid PLA. Properties that were important to us were melting temperature, shrinkage and expansion of the material under certain conditions such as temperature, speed of heating and time. At the end, we also determined the ash content. Methods or analyses that were used to determine the listed properties were differential scanning calorimetry or DSC analysis, dilatometric analysis and determination of ash content. With the DSC analysis, we determined the melting temperatures for individual materials. These results were taken into account for the dilatometric analysis, where we measured the shrinkage and expansion of the materials while they were heated. The determination of ash content was carried out at higher temperatures, as we wanted to burn the sample. In the end, only the ash remained in a cup and we calculated the percentage.
The results showed that each material has its advantages and disadvantages. For some, one analysis showed better results, while others had worse and vice versa. However, we found out that for our purpose to use a material for an investment casting and produce the model using 3D printing method is the most appropriate PVA polymer.