POROSITY OF COMPOSITE STRUCTURES BASED ON 3D-PRINTED FRAMES IMPREGNATED WITH EPOXY RESIN

Abstract

In the designs of modern machines, more and more polymer parts are used, at the same time, there is a problem of their quick replacement in case of failure. Reducing the cost and repair time can be achieved by using 3D printing by FDM method, but such parts do not always demonstrate the necessary strength. To improve their mechanical properties, a method of their impregnation after printing in epoxy resins was previously proposed. (Research purpose) The research purpose is in studying the dependence of the porosity of composite structures based on 3D-printed frames impregnated with resin on the parameters of their manufacture. (Materials and methods) Authors used samples for the first stage of the work, which are 3D-printed cylinders with different wall thicknesses and internal geometries, impregnated with ED-20 epoxy resin. The samples were cut in several sections and the number of pores in these sections was calculated. The second stage of the experiment was to evaluate the porosity of a part of complex geometry. (Results and discussion) With an increase in the percentage of filling and thickening of the wall in 3D printing, there is a tendency to reduce the number of pores. With a less dense filling of the frame and a thinner wall, the resin is worse retained in the product and partially flows out after impregnation. The best filling of a part of a complex shape was observed when it was cured in the position of the massive part up. (Conclusions) For the production of high- quality composite parts based on 3D-printed frames impregnated with epoxy resin, it is recommended to choose the largest possible percentage of filling during 3D printing and strive to position the part during the curing process after impregnation with the massive part up.