Parametric Design Of Straightening Roller And Research On Reduction Rules For Aluminum Profile Bar

Aluminum profile bar mainly used to manufacture carburetor needle valve of engine, needle valve have high standard on it’s straightness and surface roughness, but the phenomenon of space warp is easy to occur in it’s molding process, which including extrusion, cold rolling, stretching etc, so the Aluminum profile bar need to conduct no scratch precision straightening before its NC processing. In this paper, in terms of widely used triangular and four prism aluminum profile bar in engine, using a composite straightening roller system which consists of flat and vertical roller system to accomplish no scratch straightening of it.The cross section geometry characteristic of aluminum profile bar is analyzed, and a new straightening roller design method is put forward, which both considering match with cross-section shape of aluminum profile bar and conductive to form oil film at the line contact bearing area between bars and rollers. The roller diameter is determined according to bending and biting conditions, the groove structure is designed and the quantitative relationship is established between groove structure and section shape of aluminum profile. On this basis, straightening roller parametric modeling module of aluminum profile bar is established, through further development of Solid Works software, which using VB language to call the Solid Works API function.By using the elastic-plastic deformation and mechanics of materials theory, the equation is derived between straightening bending ratio and elastic region ratio of aluminum profile bar, the maximum straightening bending moment and force is calculated. The minimum oil film thickness formula is derived based on Dowson-Higginson formula, the influence factors on minimum thickness of oil film was analyzed, which including straightening bending ratio, lubricating oil dynamic viscosity and straightening velocity, and thus the technology parameters is determined to realize no scratch straightening for aluminum profiled bar.The explicit function of bending moment and curvature of aluminum profiled bar is established by using the polynomial curve fitting method, and all straightening reduction can be calculated by using two-analytic method. On the basis of this theory, roller regulate schedule operational module for aluminum profiled bar is developed by using Visual Basic software. For aluminum profile bars with a variety of original curvatures, the process of roller straightening is simulated respectively by using finite element analysis software ABAQUS, the straightening roller parametric modeling module and the roller regulate schedule operational module is verified, through analyze each straightening precision values for different bending degree profile bars.The results show that aluminum profile bars can realize no scratch precision straightening and satisfy the straightness accuracy requirements of needle valve production.