The casting technology is one of the oldest production technologies in the world but in the recent years metal additive manufacturing also known as metal 3D printing has been evolving with huge steps. Both technologies have capabilities to produce parts with internal holes and at first glance surface roughness is similar for both technologies, which means that for precise dimensions parts have to be machined in places where precise fit is necessary. Benchmark tests have been made to find out if parts which are produced with metal additive manufacturing can be used to replace parts which are produced with casting technology. Most of the comparative tests have been made with GJS-400-15 grade which is one of the most popular cast iron grades. To compare mechanical properties samples have been produced using additive manufacturing and tested for tensile strength, hardness, surface roughness and microstructure and then the results have been compared with the samples produced with casting technology. In addition, both technologies have been compared in terms of the production time and production costs to see if additive manufacturing is competitive with the casting technology. The original paper has been written in the Latvian language as part of the Master Thesis within the framework of the production technology study programme at Riga Technical University.

No abstract

Continuous casting is the most productive method of casting. Manufacturers often tend to increase casting velocity without taking into account the fact that it can cause latent defects within the casting and accordingly lead to a deterioration of the mechanical properties of product. The casting process of tin bronzes encumbers high shrinkage and high segregation in the cross section of the castings. The research was performed on three types of tin bronze alloys CuSn12-C, CuSn5Zn5Pb2-C, and CuSn7Zn3Pb7-C (EN 1982:2008). Influence of casting velocity on mechanical properties and macrostructure was studied and optimal velocity parameters were given. The following study revealed a significant effect of the velocity of continuous casting on the mechanical properties of tin bronze, which was also reflected in the macrostructure of the selected samples. Based on the results of the study the recommendations about the optimal casting parameters to increase a quality of end-product were given. The recommendations were later implemented in the manufacturing confirming the value of this study.

The paper analyzes a pressure deviation issues in a vacuum technological process, which occurs due to vacuum gauge inaccuracies during its use. For this purpose a unique vacuum system was designed and used for research. Developed system allows verification of vacuum gauges in manufacturing conditions using various experimental settings for obtaining necessary measuring data and allowing to perform an evaluation about its accuracy, repeatability and the need of calibration. In the following research several experiments with ionization vacuum gauges were carried out to obtain performance data. Presented results and vacuum system allowed to develop a new methodology of vacuum gauge verification under manufacturing conditions.

Paper presents experiments with processing parameters on additive manufacturing machine working with SLM method for stainless steel 316L. Most of the experiments which have been done before are on machines which are equipped with fiber optics lasers and these processing parameters cannot be used on machines which are equipped with CO2 lasers. Aim of research was to test processing parameter influence on printed material density and mechanical properties. Experiments were performed on Aurora Labs Titanium Pro machine which is equipped with two CO2 lasers with total power of 300 W. For processing parameters laser power was used at 300 W, laser travel speed was varied from 1500 mm/min to 2400 mm/min. Hatch distance was changed from 0.8 to 0.3 mm and layer thickness was changed from 30 µm to 50 µm. Specimens were polished and material density was evaluated by imaging analysis software and tests on tensile strength were performed.