Research On The Interference Detection In Five-axis Complex Surfaces Machining

In recent years, sculptured parts have found broad applications in the automotive, aeronautical, die and mold manufacturing industries for both functional and aesthetic reasons. Five-axis NC machine tools are widely used in sculptured surface machining for its higher performance than 3-axis machine tools. However, with two more rotational degree of freedom, local gouging and collision problem become more complicated in five-axis complex surface machining. Therefore, how to eliminate the interference problems have become an extremely important issue.Aimed at the high precision and high efficiency, on the base of a systematic analysis about the forms and characteristics of interference that exit in five-axis complex NURBS surface machining, a partition based interference-free strategy was put forward to obtain the cutter location points from the cutter contact points.The NURBS surface is first subdivided into many planar rectangular patches which are corresponding to the parameter domains of the parametric surface. Because of the relationship between subdivisions and parameter domains, the efficiency of interference detection is increased. At each cutter contact point, with the relativity of regional adjacent cutter contact points and rectangular patches corresponding with the surface parameter domains, the checking area for the kind of gouging problem that occurred between the bottom of a cutter and the complex surface are determined. Based on the checking area at each cutter contact point, the original cutter location points are obtained utilizing the selecting arithmetic of all types of interference characteristic points. The gouging problem as a result of curvature mismatch between the part surface and cutter are then detected. When this kind of interference occurred, the cutter locations are adjusted to a gouging-free position.Based on the bounding box principle and the visible cone principle, the collision between the cutter and the surface was avoided during each stage. In addition, during the process of avoiding collision between the cutter and the complex surface, the machining form was also considered, and on the pretreatment of no collision between the cutters and the complex surface, the cutting state of the cutter was optimized and the machining efficiency was improved.