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Shen B.,Tongji University | Qi D.,Tongji University | Fan L.,Tongji University | Fan L.,Tongji SMTCL Research Institute | Zhu Z.,Tongji SMTCL Research Institute
Advanced Materials Research | Year: 2011

By circumference milling with 5-axis machine or machining center has quite the machining efficiency and the surface quality of the products been improved. But when inclined inside surface of cavity is circumference milled with the default linear interpolation of rotation angle algorithm, it results in a serious non-linear error, which takes on over cutting or under cutting, e.g. the inclined plane will be over milled by the machine with dual swivel-head machining center. In order to resolve this problem, the direct interpolation algorithm of tool orientation is developed after analyzing the algorithm of linear interpolation of rotation angles and its non-linear error is. The algorithm is reported and tested with the object of a machine with AB-axis swivel head. The testing results proved that it can resolve the problem of non-linear error. © (2011) Trans Tech Publications. Source


Shen B.,Tongji University | Qi D.,Tongji University | Fan L.,Tongji University | Fan L.,Tongji SMTCL Research Institute | Zhu Z.,Tongji SMTCL Research Institute
Advanced Materials Research | Year: 2011

In the 5-axis machining, when the tool orientation approaches the one of the rotation axis, the sharp changing of the rotation angles obtained by the transforming of tool orientations causes a large over cutting or under cutting for the limit of the machine's dynamic characteristic, which is called singular problem. After analyzing the causing of the singular problem, the position of singular point, the singular value and the nonlinear error, etc, an improved plane interpolation algorithm based on plane interpolation of tool orientation algorithm is given out in the paper following with the simulation and test of the circumference milling of the tilt plane (tilt angle: 1°) separately with the plane interpolation and improved plane interpolation based on a 5-axis machining center with two swiveling heads (rotation axes: C/A). The results prove that the new interpolation is valid and correct. © (2011) Trans Tech Publications, Switzerland. Source


Fan L.,Tongji University | Fan L.,Tongji SMTCL Research Institute | Qi D.,Tongji University | Shen B.,Tongji University | And 2 more authors.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2011

The angular linear interpolation method is still applied as the default interpolation method for two rotation axes in the 5-axis milling, which causes an angle of deviation between the actual vector and the theoretical one. The circumference milling brings on an over/under cutting error, whose actual form of machining error lies on the type of machine. After analyzing, it's found that the nonlinear error is completely made by angular linear interpolation method. Based on the study of the coordinate transforming method of 5-axis machines, and the angular linear interpolation method of the rotation axis & its non-linear error, is the plane interpolation algorithm of tool orientation developed, while the algorithm is reported and tested with the object of a machine with CA-axis swivel head. The result proved that it can resolve the problem of non-linear error. © 2011 Journal of Mechanical Engineering. Source


Shen B.,Tongji University | Qi D.,Tongji University | Fan L.,Tongji University | Fan L.,Tongji SMTCL Research Institute | And 2 more authors.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2012

In order to actualize the high speed and high quality machining, and improve the micro-segment processing, which had the faults of too large capacity of the NC files and frequent acceleration/deceleration controlling in the machining process, a high-speed adaptive NURBS fitting method was developed to actualize the smoothing milling, which was under the constraints of least square approximation algorithm and weight factors of data points. The new fitting algorithm was a high-speed adaptive interpolation algorithm based on NURBS fitting for micro sections. The key of the new algorithm was to fit the micro sections into a new tool path made of NURBS. And then, the new tool path can be interpolated easily by the NURBS interpolation algorithm. Under this method, the machining with micro sections of tool path will be smooth and efficient. Source

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