The main goal of roughing die roughing is to pursue the material removal rate per unit time and to prepare the geometric profile of the workpiece for semi-finishing. During the cutting process, the metal area of ​​the cutting layer changes, causing the load to be changed by the tool, the cutting process is unstable, the tool wear speed is not uniform, and the quality of the machined surface is degraded. Many of the CAM software currently developed can maintain a constant cutting condition by the following measures, thereby obtaining good processing quality. Constant cutting load. A constant cutting area and material removal rate are obtained by calculation to balance the cutting load with the tool wear rate to improve tool life and machining quality. Avoid suddenly changing the tool feed direction. Avoid burying the tool in the workpiece. For example, when machining the mold cavity, the tool should be prevented from being inserted vertically into the workpiece, but the inclined lower knife method should be used (the common inclination angle is 20° to 30°). It is best to use the spiral lower knife to reduce the tool load; when machining the mold core Should try to lower the knife from the outside of the workpiece and then cut it horizontally. When cutting and cutting out the workpiece, the tool should be cut and cut as much as possible by tilting (or arc) to avoid vertical cutting and cutting. Climbcutting reduces cutting heat, reduces tool force and work hardening, and improves machining quality. The main goal of semi-finishing semi-finishing is to make the contour of the workpiece flat and the surface finishing allowance uniform, which is especially important for tool steel molds, because it will affect the change of the cutting area of ​​the tool and the change of the tool load during finishing. , which affects the stability of the cutting process and the quality of the finished surface. Roughing is based on a volume model and finishing is based on a surface model. However, the previously developed CAD/CAM system has a discontinuous geometric description of the part. Since there is no intermediate information describing the machining model after roughing and finishing, the residual machining allowance distribution and the maximum remaining machining allowance of the roughed surface are not described. Both are unknown. Therefore, the semi-finishing strategy should be optimized to ensure a uniform residual machining allowance on the surface of the workpiece after semi-finishing. The optimization process includes: calculation of the contour after roughing, calculation of the maximum residual machining allowance, determination of the maximum allowable machining allowance, and transformation of the profile division (such as grooves, corners, etc.) for the remaining machining allowance greater than the maximum allowable machining allowance. The radius is smaller than the radius of the roughing tool) and the calculation of the tool path during semi-finishing. The existing CAD/CAM software for high-speed machining of molds mostly has the residual machining allowance analysis function, and can adopt a reasonable semi-finishing strategy according to the size and distribution of the remaining machining allowance. For example, OpenMind's HyperMill and HyperForm software provide methods such as beam milling and residual milling to remove corners with large machining allowances after roughing to ensure a uniform machining allowance for subsequent processes. Local milling of PRO/ENGINEER software has similar functions. For example, the residual machining allowance of the local milling process is equal to the roughing. This process uses only a small diameter milling cutter to remove rough cut uncut corners. Then, semi-finishing is performed; if the remaining machining allowance value of the partial milling process is taken as the remaining machining allowance for the semi-finishing, the process can not only remove the uncut corners of the roughing, but also complete the semi-finishing. The high-speed finishing strategy of a finishing tool depends on the point of contact between the tool and the workpiece, and the point of contact between the tool and the workpiece varies with the slope of the surface of the machined surface and the effective radius of the tool. For complex surface machining composed of multiple curved surfaces, continuous machining should be performed in one process as much as possible, instead of processing each curved surface separately to reduce the number of lifting and lowering. However, due to the change in the slope of the surface during processing, if only the sideover of the machining is defined, the actual step distance on the surface with different slopes may be uneven, which may affect the processing quality. Optimization of feed rate Many CAM softwares now have an optimized adjustment of the feed rate: in the semi-finishing process, the feed rate is reduced when the cutting layer area is large, and the feed rate is increased when the cutting layer area is small. The optimized adjustment of the feed rate can make the cutting process smooth and improve the quality of the machined surface. The size of the cutting layer area is completely calculated automatically by the CAM software, and the adjustment of the feed rate can be set by the user according to the processing requirements. 4 Conclusion Mold high-speed machining technology is the integration of a variety of advanced processing technology, not only involves high-speed machining technology, but also high-speed machining machine tools, CNC systems, high-speed cutting tools and CAD / CAM technology. The high-speed mold processing technology has been widely used in the mold manufacturing industry in developed countries, and the application scope and application level in China still need to be improved. We will vigorously develop and promote the application of high-speed mold processing technology to promote the overall technical level and economy of China's mold manufacturing industry. The improvement of benefits is of great significance. Concerned about surprises Tag: High-speed machining Machining allowance Cutting process Machining quality Tool Previous: Introduction to FPC Surface Plating Knowledge Next: How to use gauges? Filter Cylinder,Filter Drum,Filter Cartridge Galvanized Steel Wire Co., Ltd. , http://www.nswiremesh.com
Pro/Engineer solves the above problem by defining the amount of knife on the side while defining the height of the machined surface (Scallopmachine); HyperMill provides an Equidistant machine to ensure uniform path between the passes. The amount of knife on the side is not limited by the slope and curvature of the surface, ensuring that the tool will always receive a uniform load during the cutting process. In general, the radius of curvature of the finished surface should be greater than 1.5 times the radius of the tool to avoid sudden changes in the feed direction. In the high-speed finishing of the mold, the feed direction should be changed by arc or curve as much as possible during each cutting and cutting of the workpiece, avoiding the use of linear transfer to maintain the smoothness of the cutting process. 