The Missile Radome Cam Software Design And Development, Precision Grinding Machine Tool

The missile radome, a thin-wall and revolving body with complicated curved surface, is one of the key parts of homing guidance missile. The hitting accuracy of the missile is seriously affected by the manufacturing precision of the radome. But the semi-finished radome mostly can't meet the demand of the electromagnetic properties of the high-precision homing guidance system because disparity of radome material's dielectric coefficient and errors of the radome geometric thickness induce larger error of the electric thickness. So it is necessary to precisely grind inner surface to compensate disparity of material's dielectric coefficient by changing the geometric thickness of radome, so as to reduce error of the electric thickness. In order to establish the datum surface before precisely grinding inner surface, it is necessary to reconstruct of the free curved surface according to the measurement data. Tool-path of grinding inner-surface is then planned on the reconstructed offset surface according to required grinding allowance. Finally, NC G-Code for precision grinding is automatically generated.A bicubic B-spline method based on the least squares technique is presented to reconstruct 3D inner surface of the radome inner-surface both before and after ground, and it is successfully applied in the precise grinding system of missile radome. The practical test shows that the inner surface reconstructed by this method is smooth and accurate even if the discrete data are not double sequential.When planning the tool-path on the offset surface, it is necessary to determine the offset points according to the finished inner surface. The key to determine the offset points is to calculate the normal vectors at the corresponding points on the finished inner surface, which can be calculated according to the tangent vectors at those points along the two parametric directions. An tool-path planning method, unequally-spaced sectional ring-cutting method, is presented, which is a combination of determining the width of the machining belt by equal-residual-height method along the generatrix direction and determining the steplength by an isoparametric method along the circumferential direction. G-Code generated based on the method has been able to grind the missile radome's inner-surface accurately and efficiently.The CAM software is developed based on VC++ and object-oriented programming technology, which has such functions as reconstruction of generatrix line, circumferential line and inner surface both. before and after ground, reconstruction of the offset surface, error analysis of the reconstruction, generation of the NC G-Gode. The software has expandability, transportability and friendly interface, it has been applied successfully in the precise NC grinding system of missile radome.