Papers by Author: Stefan Gaspar

Abstract: With a pressure die casting process, one of the important factors affecting the quality of castings represented by porosity is plunger pressing velocity determines the regime die cavity filling and correct determination of dose mass of a molten metal required for one casting cycle. The mass is given by a total of the net mass of a casting, overflows, a gate system and a metal rest inside a filling chamber (the tablet height). As a rule, the tablet height represents the largest mass ratio regarding the waste metal. A correct determination of the tablet height is important from both economical and qualitative aspect of a pressure die casting process.

Abstract: In these days in foundry branch there is a rapid development of sectors of special casting technology with the aim to increase the quality and the efficiency of pressure casting production. Internal homogeneity of pressure casting, characterized by the extent of porosity can be affected by the setup of technological parameters of pressure casting and last but not least by vacuuming the moulds, that means to exhaust air and gases from the mould cavity. Contribution is specifically aimed on the analysing the impact of degassing pressure moulds on the porosity of pressure casting from EN AC43400 Alloy.

Abstract: The production of die castings cast into a metal mold has in recent years achieved an expansive growth in the volume as well as the range of production and that is particularly in aviation and automobile industry. In the process of die casting the final quality of a cast is influenced by a great number of factors. The main factors of die casting are: pressing velocity, increase pressure, the melt temperature and the mold temperature. A primary criterion for achieving reliability, efficiency and quality of production is to ensure minimization of the castings defects occurrence in castings correct setting technological factors of die casting. The presented paper deals with the experimental assessment of the impact of increase pressure on the mechanical properties and homogeneity of a die cast.

Abstract: The production of die castings cast into a metal mold has in recent years achieved an expansive growth in the volume as well as the range of production and that is particularly in aviation and automobile industry. In the process of die casting the final quality of a cast is influenced by a great number of factors. The main factors of die casting are: pressing velocity, increase pressure, the melt temperature and the mold temperature. A primary criterion for achieving reliability, efficiency and quality of production is to ensure minimization of the castings defects occurrence in castings correct setting technological factors of die casting. The presented paper deals with the experimental assessment of the impact of increase pressure on the mechanical properties and homogeneity of a die cast.

Abstract: In the pressure die casting process, a great attention is paid to a die castings quality improvement. This quality has to be ensured with a great reliability and, at the same time, it is necessary to apply control methods to a technological process which provide a complete picture of a die casting process as well as internal quality of the produced die castings. It requires control of the present technological factors of a pressure die casting process. The contribution deals with the effect of die casting plunger velocity inside a filling chamber on mechanical properties of a die casting product from EN AC 47100 alloy.

Abstract: Recent research in the process of die casting production of aluminium alloys which are nowadays deeply implemented in the rapidly developing automobile, shipping and airline industry aims to increase the manufacture and quality properties of the casting in order to obtain its high mechanical properties at acceptable economic costs. In terms of ensuring the quality indicators in the production of aluminium castings it is necessary to pay close attention to internal structural quality of the castings characterized by type and extent of foundry defects (cavities, Al₂O₃ particles, internal cold laps). The presenting contribution deals with the analysis of the fracture process, the microorganism disturbance of test samples, the impact of casting speed on the occurrence and extent of the castings porosity and reasons for the internal foundry defects of casting alloys EN 43100 manufactured by die casting technology.

Abstract: An introduced article deals with the possibility of re-use of waste materials in production. The observed properties are the tensile properties of newly created material, namely yield stress, stress at break. Changes in strength characteristics and suitability of replacing the pure, primary material with the secondary, waste plastics were determined by material tests. The report gives a cross-section in methodology of tests performing, results processing and implementation into practice.

Abstract: The structure and properties of cast metals and alloys are in a high degree influenced by crystallization conditions. By the technological interventions into the crystallization process the mechanical properties and structural parameters of castings can be enhanced. The present contribution deals with the regularities of crystallization of alloys Al-Si produced by die casting process.

Abstract: The structure of casting silumins (Al-Si alloys) contains a big share of eutecticum (40-75%) which, as mentioned afore, enhance fluidity and decrease tendency towards formation of clefts and microporosity. Due to this fact the properties of α - phase on one hand as well as quantity, morphology, size, and distribution of eutectic silicium on the other hand are the most significant factors influencing mechanical properties of the casting.

Abstract: The paper deals with analysis of influence of pressing speed, of melt temperature and of casting position in a mold upon ultimate tensile strength R_m of die casting from aluminium. The monitored parameters of die casting are very important in terms of production efficiency and quality of casting, which is positively reflected in economic indicators of the production.