Programming Error Analysis Method For Machining Spiral Rod

At present, the calculative method of cutter-contact points and cutter-path when machining helicoids with section envelope principle has been succeeded to a certain extent, but there is lack of the study and method for such arithmetic and technics. So on the basis of the algorithm of seeking minimal orientation-distance, this paper probe into error analysis method for machining spiral rod by non-instantaneous section envelope principle and make analysis for primary influencing factors.Non-instantaneous section envelope machining principle and the algorithm of seeking minimal orientation-distance are expounded theoretically. Non-interference cutter path is gained after the use of the algorithm of seeking minimal orientation-distance. According to the characteristic of helical surface, "the envelope surface simulation algorithm" for calculating actual machining helicoids is put forward at the presupposition of cutter surface and cutter path. Error analysis model and algorithm in the normal direction for factual machining curved surface is set forth in allusion to the demand that for complicated spiral rod machining precision should be scaled from mesh precision. In this algorithm, for seeking the point of intersection between the normal line passed the academic point and the factual machining curved surface, projection analysis method in the tangent plane is used, the quadrant seeking algorithm is brought forward and algorithm is programmed by the programming language C, detailed error analysis with example is done. The influence of Archimedes spiral curve interpolation on machining precision is analyzed, for the fact that the actual cutter path among the programmed points in the machining of spiral rod is Archimedes spiral curve. On the basis of that, the factors such as the step among the programmed points ,the radius of cutter cirque and the fixed angle of cutter are discussed, the primary factors of influencing machining precision are the section profileof work-piece and the step among the programmed points. Using envelope surface simulation algorithm, the influence of the cutter fixed height on the machining precision of spiral rod is analyzed; the concept of compensatory phase angle and compensation for such error on phase are advanced. The normal error after phase compensation is considered as the analysis gist, the rule of error is summarized. By the analysis, the essential reason for error is the non-consistence between the factual machining path and the calculative cutter one. Such error belong to NC programming error, so the compensational measure form software is set forth.By the study on error analysis method and the summarizing of error rule, the primary factors of influencing machining precision of spiral rod are gained, the measure for improving machining precision is elicited. Thus, the correctness of the algorithm of seeking minimal orientation-distance is proved again, the theory of non-instantaneous envelope machining is perfected, the practice guidance is acted on.