Influence of Shielding Gas and Mechanical Activation of Metal Powders on the Quality of Surface Sintered Layers

The thesis analyses the influence of argon shielding gas and mechanical activation of PMS-1 copper powder and DSK-F75 cobalt chrome molybdenum powder on the surface sintered layer quality under various sintering conditions. Factors affecting the quality of the sintered surface and internal structure are studied. The obtained results prove positive impact of the shielding gas and mechanical activation. Sintering PMS-1 copper powder in argon shielding gas after mechanical activation leads to reduced internal stresses and roughness, as well as improved strength characteristics of the sintered surface. Analysis of sintered samples of mechanically activated DSK-F75 cobalt chrome molybdenum powder shows that the strength of the sintered surface grows porosity and coagulation changes

Analysis and prediction of copper surface roughness obtained by selective laser melting

The paper presents the results of experimental studies of the effect of mechanoactivation of the powder, argon shielding gas and the effect of technological modes of melting: the speed of the laser beam, the power of laser radiation, the scanning step, the preliminary temperature of heating the powder material on the surface roughness of the copper powder material obtained by selective laser melting. Experiments on the melting of copper powder are implemented on the installation of layer-by-layer laser melting of the original design, which allows to adjust all technological modes of melting. The surface roughness is determined on the non-contact digital microscope Olympus LEXT OLS4100. The mathematical dependence of the surface layer roughness of copper powder on the technological modes of melting is obtained on the basis of the theory of experiment planning and static processing of the results. The significant parameters of the regime-the power of laser radiation, the speed of the laser beam, the scanning step affecting the roughness of the layer. The positive effect of mechanical activation of powder material and protective atmosphere on the quality of the surface layer is shown

The Development of Equipment for the Disposal of Solid Organic Waste and Optimization of Its Operation

The paper describes the developed system for the thermal utilization of solid organic waste, which can simultaneously process the paper, wood, rubber, plastic, etc. A method for improving the efficiency of the equipment, due to optimization of the gas extraction system was proposed. The influence of the characteristics of installed equipment and modes of their work on energy savings and efficiency of the gas extraction system was also determined. Optimization work which includes the introduction into the exhauster control system of the frequency converter, can save up to 70% of electricity and increases the life of the equipment

Influence of layer-by-layer laser sintering conditions on the quality of sintered surface layer of products

The influence of technological modes of sintering: the displacement velocity of laser beam V, laser power P, scanning step S and preheating temperature of powder material t on the quality of sintered surface layer of aluminum powder PA-4, copper powder PMS-1 and cobaltchromium- molybdenum powder DSK-F75 were studied

Improvement of the Sintered Surface and Bulk of the Product Via Differentiating Laser Sintering (Melting) Modes

Selective laser sintering (melting) enables using metal powdered materials to manufacture products of any geometrical complexity, requiring no preliminary costs to prepare processing equipment. However, quality of the sintered surface is often inadequate as against the product manufactured traditionally. Manufacturing a high quality product requires solution of such vital task as prediction of the sintered surface roughness. The authors address to the effect of laser sintering modes on roughness of the surface, sintered of copper powdered material PMS-l (IIMC-1). The dependence of roughness of the surface layer sintered of copper powder material PMS-l upon sintering process conditions is expressed mathematically. The authors suggest differentiating sintering modes to improve the sintered surface and the bulk of the product and dividing them into rough, semi-finishing, and finishing ones

Process Conditions of Forming the Surface Layer of Aluminum Powder Product by Layer-by-layer Laser Sintering

The paper presents data on state of the art in selective laser sintering of products. Layer-by-layer sintering is shown to be a future-oriented technology, making it possible to synthesize products of metal powder materials. Factors, influencing the quality of a sintered product, are revealed in the paper. It presents outcomes of experiments, focused on the dependence of surface layer thickness of sintered aluminum powder PA-4 on laser processing conditions. Basic factors, influencing the quality of a sintered surface layer include laser power, speeds of scanning and moving the laser beam on the layer of powder. Thickness of the sintered layer varies from 0.74 to 1.55 mm, as the result of changing the laser processing conditions