This paper deals with experimental investigations and numerical simulations of HELICOIL® inserts in ABS-M30 plastic. The aim is to explore the possibilities of modelling HELICOIL® inserts using Finite Element Method (FEM) and thus predict the load-bearing capacity of these inserts. The motivation was based on a previously published article that dealt with the topological design of the robot manipulator arm shape. During the mechanical tests, the structure of the arm did not collapse, but the HELICOIL® inserts were torn out. To determine the load-bearing capacity of HELICOIL® inserts, the necessary experimental tests were designed and carried out. FEM calculations of the inserts were adjusted to the obtained data. The results from the FEM were verified in an experimental validation test.