The paper focuses on an analysis of materials produced by modern classic additive method direct metal laser sintering (i.e. powder metallurgy). Direct metal laser sintering belongs to file of additive technologies of rapid prototyping. Rapid prototyping technology is a progressive group of methods used for fast creating of models, prototypes and components directly from 3D data. According to a used technology photopolymers, thermoplastics, specially modified paper or metal powders are used in rapid prototyping machines. Nowadays those production machines creates not only models and prototypes, but they are used to manufacture tools, forms and components for small series production. The purpose of the theoretical part is to gain in depth understanding of exactly what is the principle of direct metal laser sintering and what are properties of explored materials. The practical part analyses structures of materials used by classic and powder metallurgy. It concentrates on samples preparation, their analysis (using light and electron microscopy) and testing. Samples are analysed by mechanical tensile test and Vickers hardness test. The paper also compares sintered samples with steel equivalents produced by classic metallurgy giving final recommendation.
An investigation on reaming using minimal quantity lubrication (MQL) was carried out with the scope of documenting process capability using a metrological approach. Reaming tests were carried out on austenitic stainless steel, using HSS reamers with different cutting data and lubrication conditions. The reaming operations were compared with respect to a number of evaluation parameters, both hole quality (diameter, roundness, cylindricity and surface roughness) and cutting forces (reaming thrust and torque).Absolute average values as well as experimental standard deviations of the evaluation parameters were calculated, and uncertainty budgeting was performed for all measurands. Results show that reaming operations at lower cutting speed and feed produce low process scatter. The use of smaller depth of cut (i.e. smaller reamer diameter) resulted in larger reaming torque scatter than when a larger depth of cut was employed. The suitability of MQL for reaming was proven under the investigated process conditions, concerning both the quality of the machined holes, in terms of geometrical characteristics and surface finishing, and the process quality, with respect to reaming torque and thrust, along with their repeatability.
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