Planning And Experimental Study On Milling Path Of Complex Mold Cavity

Mold manufacturing industry is an important part of Chinese industrial development,andthe importance of mold manufacturing industry in Chinese economic development is self-evident.At the same time,the development of mold manufacturing industry is mainly dependent on the continuous improvement of CNC machining technology.At present,in the automotive,aerospace,ship,etc.as the representative of the industry in order to gain greater advantage in the market competition,putting higher requirements on the mold products.One of the most important requirements is how to reduce the cost of mold products,improving the efficiency of mold manufacturing.Mold cavity processing as an important part of the mold manufacturing process,the processing time is quite time-consuming,but also the most difficult part of CNC mold products processing.The main work of this paper is to study the different CNC machining tool path generation strategy and optimizing the processing parameters.The purpose is to improve the mold cavity processing efficiency.Firstly,the one-way and zigzag tool path is taken as the object of study,and the intersection of the scanning line and the profile of the flat cavity is obtained by scanning line algorithm.The basic segment of the tool path is obtained,In order to improve the processing efficiency,making use of regional segmentation algorithm divided the flat cavity processing area into different sub-processing area,reducing the number of tool lift in CNC machining process effectively.Secondly,plan the contour-parallel tool path on the machining area of the flat cavity.The bounding box method is used to divide the plane cavity processing area into a series of grids,establishing the one-to-one correspondence between the offset line and the grid.The problem of the intersection of large-scale offset lines is transfered into the local intersection calculating problem in the grid-inside,increasing the intersection calculating speed between the offset line segment.In this paper,the interference ring formed in the process of plane cavity contour offseting is removed by equidistant method.Firstly,Offset the planar cavity contour line segments continuously,eliminating the local interference ring,and then using the interference ring removal algorithm eliminating the global interference ring.When the global interference ring and the local interference ring are eliminated,then generating the processing tool path without any interference ring.Finally,the cubic B-spline curve is used to perform thesmoothing process to the effective loop after the offset,fitting the saw tooth path segment formed during the offset processing.Finally,for the three commonly used cavity cutting modes,one-way cutting mode,zigzag cutting mode,contour-parallel cutting mode,the processing simulation and the actual processing experiment on a typical cavity was made,The effects of different feed rates on the cutting time at different cutting modes and the same cutting mode were analyzed respectively.The importance of cutting mode and feed rate in tool path planning is demonstrated.A kinematic model for cavity machining is given,which explains the deviation between the actual processing time and UG simulation processing time.