Improvement of thin-walled cylindrical workpiece machining accuracy by means of control programs

摘要

Treatment of thin-walled cylindrical workpieces is accompanied by displacements caused by the clamping forces (locking). These displacements affect the total error of the treatment and reach values commensurable with the manufacturing tolerances of the product. Development of programs for technological process design, Computer Aided Design / Computer Aided Manufacturing (CAD/CAM), is based on economical precision. The displacements caused by the clamping forces are usually not considered. Thus implementation of the CAD/CAM process impairs the quality of the designed products and the precision of the treated workpieces. Hence calculation of the clamping forces which cause displacements within the interval of tolerance is a topical problem. A procedure for calculation of permissible clamping forces under various schemes of loading of rings, cartridges and pipes was developed by the authors. An algorithm and a program in FORTRAN language were compiled and realized on a PC computer. The permissible clamping force [Q] and the permissible feed [f] ensuring the permissible cutting force P{sub}Z are determined depending on the allowable form deviation [△F]. A complex of equations for calculation of maximum displacements of rings, cartridges and pipes under various loading schemes, and the sources in which the equations appeared in a general form, are presented. The procedure can be used for calculation of displacements and stresses in the design, production and operation of thin-walled cylindrical workpieces and other non-rigid parts.