At present, the CAD system is mainly used for the design of auto parts, and the design of the parts is completed through reverse engineering and various tests. CAM software is used to process the complex surface of the mold. However, CNC machining plays the role of ensuring the accuracy of design and processing. Forlong analyzes the relationship between the application of 5 axis machining centers in mold processing and the quality of auto molds.
In the process of auto mold manufacturing, if a 3 axis machining center is used to process deep cavity molds, the tool holder and tool must be lengthened in order to achieve this. However, if the 5 axis machining service is used for machining deep and steep cavities, to create better technological conditions for machining, the additional rotation and swing of the workpiece or spindle head can appropriately shorten the length of the tool, thereby preventing the occurrence of collision between the tool, the tool holder and the cavity wall, and reducing the vibration and damage of the tool during machining. In this way, the service life of tool is also prolonged, and the surface quality of the mold and the processing efficiency are also greatly improved.
For the processing of the sidewall of the mold, the tool length of the 3 axis machining center is larger than the depth of the sidewall, and the length of the tool is also determined by the depth of the sidewall. If the length of the tool is increased, its strength will be significantly reduced. If the tool length is higher than 3 times the diameter, the phenomenon of cutter back-off will occur, so the quality of the workpiece cannot be guaranteed. If the 5 axis CNC machining is used to process the sidewall of the mold, the swing of the spindle or the workpiece can be used to make the tool and the sidewall of the mold appear vertical. When milling the sidewall of the mold, a plane milling cutter can be used, which can improve the quality of the workpiece and prolong the service life of the tool.
When machining the flat surface of the mold, the 3 axis machining center needs to use a ball cutter for fine milling so as to obtain a good surface quality. In this case, the tool path needs to be increased, but the center rotation speed of the ball end cutter is almost zero. During mold processing, the degree of tool damage is great, the service life of the tool will be shortened, and the surface quality of the mold will also be lowered. If 5 axis CNC machining is adopted to process a relatively flat surface, the tool can be placed on the workpiece at a certain angle for processing, which can increase the relative linear speed between the workpiece and the ball end cutter, thereby improving the service life of the tool, and greatly improving the surface quality of the workpiece.
When machining a mold with an irregular surface, it was generally done by a 3 axis machining center in the past. The direction of the tool cutting the mold is to move along the entire cutting path. The cutting process will not change. At this time, the cutting state of the tool tip cannot guarantee the perfect quality of each part of the mold.
When a 5 axis machining center is used to process a mold with a three-dimensional curved plane, the tool can always maintain a good working state during the cutting process of the mold, and the working angle of the tool can be changed in any area of the machine tool so as to complete the machining of the geometric mold.
When machining the inclined hole on the inclined surface of the mold, the use of 5 axis CNC machining can place the spindle on the vertical side of the inclined surface of the workpiece and position it at the accurate hole position through the machining action of the swing head machine tool. In order to accurately machine the inclined hole on the mold, at least two linear axis interpolation movements are required, while the accuracy of the hole position is also significantly reduced in this process.
If you want to mill a straight line with no direction change, you only need to draw a straight line from the tool tip. If the direction needs to be changed, the tool tip can draw a curve, and the tool tip direction is changed. At this time, if you want a straight line, you must give this curve necessary compensation, which is extremely important when the a 5 axis machining center is applied.