Optimization of the support structure of a multipurpose machine tool

Modern manufacturers of multipurpose machining centers design and manufacture equipment according to the criterion of maximum rigidity and productivity to ensure processing of the maximum range of materials at high accelerated cutting modes. As a result, in most machine-building tasks, the support structure of the machine is unnecessarily rigid due to the production of excessively massive frames and body elements of the machine. These structural elements have high weight and size characteristics, which leads to an increase in inertial loads on the drive feed mechanisms. In serial and mass production, heavy elements of the support structure significantly increase the energy consumption of the machine, while reducing labor productivity. Modern methods of design optimization, together with finite element methods, allow solving the problem of energy efficiency and productivity by modifying the support structures according to the criterion of minimum rigidity in accordance with the boundary conditions of the cutting forces when processing the selected product range.

TWO–COMPONENT RESTORABLE TOOL SYSTEM MULTI–PURPOSE MACHINE WITH AN INSTANTLY REFILLED TIME RESERVE

The object of the research is the technical system of a multipurpose machine tool, the tools of which can fail and be restored. A failed tool remains functional for some time due to a temporary reserve until a parametric failure occurs, the magnitude of which is random. All random variables describing the system have general distributions. The apparatus for constructing a mathematical model of the described system is a semi–Markov process with a discrete–continuous phase space of states. The stationary distribution of the embedded Markov chain is found explicitly. For systems with parallel connection, series connection with disconnection and without disconnection of elements, the stationary time between failures of the system, the stationary time spent in the state of failure and the stationary system availability factor are found. A numerical example shows the dependence of the stationary characteristics of the system on the size of the time reserve.