This article examines the process of technological processing of semi-finished product in the manufacture of rod profile products from fibrous composite materials, in particular - round. The purpose is to determine the theoretical value of the parameter which ensures the necessary impregnation of the winding layer during the final moulding of profile products. It is mentioned that in order to ensure a defined structure and degree of filling during the production of rod profile products from spirally reinforced semi-finished products, they are compacted. Compaction can take place in one of two methods: by pressing in a spinneret, crimping with winding. The second method is used in the production of round cross-section rods. In this case, the spirally reinforced structural elements, which initially have a circular cross-sectional shape, deform and acquire an elliptical shape. At the same time, the degree of reinforcement filling of the central part of the structural element changes. The volume of binder removed during deformation per unit time is presented as a function of the ellipse parameter.The displacement of the binder at steady-state mode of moulding is considered.Law of change of pressure gradient along the length of formed element before molding front is defined. The volume of binder removed during bundle formation per unit time is determined. Required molding pressure necessary to ensure a given degree of filling has been determined. It is shown that it is possible to calculate the parameters of a deformed element that will ensure that the binder fills the space between the elements. An equation for determining the value of the parameter of the degree of crimping of an element, depending on the diameter of the used semi-finished product and the thickness of the winding layer is obtained. Data on critical values of a parameter of a degree of crimping of element, depending on diameter of a half-finished product and thickness of a layer of a winding is resulted. A method of determining the parameter of the degree of crimping of the element, which ensures the necessary impregnation of the winding layer during the forming of the profiled products, is proposed.