Optimization of multifunction machines constructions with required accuracy and productivity

One of the main criteria of the supporting constructions (column, spindle head, bed) of the multifunction machine is the mass of constructions. It is required to find such distribution of material in the supporting constructions whereby conditions of strength reliability are satisfied with minimum possible mass. Supporting system, consisting of these optimum supporting constructions, has to provide the precision and productivity of machining. In order to support business objectives, the technology of rational designing of supporting constructions, offered by us, uses the principle of decomposition and the integrated work of the finite elements method with optimization methods. The main stages of this technology - optimization of the supporting system of the machine with the supporting constructions simplified on geometry and optimum design of the individual supporting constructions for definition of real geometry of cross section are considered. Calculation of the supporting system with the simplified supporting constructions (without edges of rigidity, partitions, etc.) is made for limit and operating conditions of working. Calculations showed that in the stage of the machine supporting system modeling for typical operating conditions the mass of the supporting system due to optimization is 35% less than the production version. Active restrictions in strain of an end face of a spindle in the direction of action increases the cutting force. Due to high dimension of calculation models of the supporting constructions it is offered to use the substructure at a stage of optimum design of the individual supporting constructions on the basis of the principle of decomposition. The calculated strain field of the optimal column substructure is consistent with the strain field of the column, which is obtained when calculating the machine supporting system, consisting of simplified supporting constructions at satisfaction of precision standards of working. Restriction on the allowed strain for knots on an axis of y (0.45 ∙ 10-6) is strictly carried out, and on the rest settlement strains there are less than allowed. The turning angle of the optimal column with real cross-section is less, than the turning angle of the column as part of supporting system with the supporting constructions of simplified geometry - 0.0778 rad and 0.1495 rad, respectively, i.e. torsion rigidity of the optimal column is higher. As a result of optimum design, a mass of the pallet, consisting of the moving-rotary table, is reduced by 35.5 % in comparison with a production version.

multifunction machines, design, supporting system, supporting constructions, finite elements method, optimization methods