Research On Trajectory Generation Of NC Machining For A Centrifugal Pump Impeller

Centrifugal pump impeller serves as a core flow part of pump components,its' surface creating precision will directly affect the efficiency of the pump.The traditional processing method is only applicable to the workpiece with little distortion and simple geometric shape,and it is difficult to ensure the accuracy of the centrifugal pump impeller.In view of the above situation,combining with the characteristics of the five axis NC machining technology,the five axis NC machining processing technics of the centrifugal pump impeller is planned,and a constant scallop trajectory generation method is proposed.Meanwhile,in order to avoid the interference in the machining process,a new method for the axis vector programming of the guide curve is presented.In the programming,the CLS file of tool bit is obtained,and the NC code is generated by UG/post-processing.In order to verify its effectiveness,the simulation process is carried out in VERICUT.Finally,the trial cutting experiment was carried out on the five axis NC machine tool,and the results showed that the impeller's creating precision reached the expected effect after measuring and comparing.In the planning of constant scallop tool path for bland with finish machining.Firstly,the geometric morphology on the processing surface is analyzed,and a trajectory is extracted from the boundary curve as the initial trajectory and according to the discretion of permitting chord tolerance,a sequence of cutter contact points are formed.Then,the cross section of the construction method is perpendicular to the feed direction In this sequence,and a circle arc is constructed with the spacing given scallop high value obtained by the radius of cutter contact points in each sectional plane.After that,along the tool axis directions the cutter location points are calculated to processing the tool-path.Numerical example shows that the algorithm is effective and feasible.When planning tool axis vector.First,the geometric shape and surface processing between adjacent bland is analysised,by looking for and migrate the coated border midpointbetween adjacent blades,the tool axis vector guidance curve has been generated.It started from the CL point and end of the guided line point.In order to achieve the proposed algorithm,centrifugal impeller machining module is designed by UG secondary development technology.The module simulations show that a smooth tool path will be generated,assuming a given residual scallop height of0.02 mm,with a Root Mean Square(RMS)residual scallop height of 0.0087 mm,It also generates tilt angles(10.3762o,24.8914o),roll angles(71.4596o,84.5163o)and a cutter axis which rotates smoothly without aviation.After the NC program has been verified by the simulation process,the trial cutting experiment is carried out,and then the non-contact measurement of the structure light binocular grating is made,and the precision creation of the centrifugal pump impeller is achieved.