STUDY OF THE FRICTION FACTOR OF POLYMER MATERIALS FOR 3D PRINTING OF ROLLING STOCK STRUCTURAL ELEMENTS

Additive technologies are represented by various methods of 3D printing and are increasingly being used in various industries around the world. For example, printing with metal powders is used for the production of such structural elements as various arm supports in the aircraft industry or the manufacture of spacecraft hulls. The use of 3D printing with the use of polymer materials makes it possible to manufacture, for example, various gears for non-principle mechanisms. The use of such technology in pneumatics is also relevant. However, at the same time, the possibility of using these technologies for the manufacture of various pneumatic devices has not been widely studied up to now. In the course of studying this issue, a pneumatic gearbox was made. However, it was found out that one of the problems that does not allow to design and manufacture a normally functioning pneumatic device is an unknown value of friction factor of the materials of which its elements are made. The study objective is to find out the static friction factor of products made of polymer materials using 3D printing technologies. The necessity of this study is explained by the problems that arose as a result of testing a high-performance pneumatic gearbox manufactured using additive technologies applying various polymer materials. The main problem of this device is the density violation of fixed detachable joints of gearbox case parts and covers. Since the medium to be used is compressed air under a pressure of 0.9 MPa, any density violation can lead to the gearbox destruction or to air losses from the braking system of a freight train due to an increase in the number of leaks in the pipeline for additional power supply to the spare reserve. The paper presents the results of experimental studies on finding the friction factor of various types of materials used in 3D printing. The obtained friction factors are required for the design of seals of pneumatic devices according to generally accepted methods.