The paper presents the properties of plastics under the trade names of PMMA and Midas, and of Formowax, Romocast 305 and Romocast 930 casting waxes. Their effect on the quality of foundry patterns used in the manufacture of ceramic moulds for precision casting is also discussed. From the selected materials for foundry patterns, samples were made for testing using the following methods: (i) 3D printing in the case of plastics, and (ii) conventional method based on tooling in the form of metal moulds (dies) in the case of casting waxes.

The most important physico-mechanical properties of materials for foundry patterns were determined, i.e. linear shrinkage, softening temperature, relative elongation and coefficient of thermal linear expansion. Bending tests were carried out on samples of patterns printed and made in metal moulds, including determination of the surface roughness of patterns.

After the process of melting out patterns from the cavities of ceramic moulds in an autoclave, the degree of their melting out was visually assessed (i.e. the residues from pattern removal were evaluated). The ash content after burning out of foundry patterns was also determined. The conducted tests allowed comparing the important parameters of materials used for foundry patterns and assessing the suitability of selected plastics as a material for foundry patterns used in the manufacture of high-quality precision castings.

The topic of this paper is the description of the General Contractor Selection procedure using the AHP method. Another aim of this paper – within the scope of decision-making – is the determination of the potential General Contractor’s evaluation criteria and the selection of the best Bidder using the AHP method. We included the description of the conducted tender proceeding for the purpose of the procurement’s subject. As the decision-making options, we adopted four construction companies that submitted their bid. A key element of the studies was the paired comparison of all hierarchical structure elements. We estimated the local weighting coefficients and global priorities of particular decision-making options as well as analysed the vulnerabilities of the obtained results.