First, cnc precision machining order
When the mold is very large and deep, the rough machining and semi-finishing before quenching is done with soft machining, and the finishing after quenching is done with hard machining; small and shallow molds can be milled at once after quenching. If the mold wall is very thin and the cavity is very deep, electric machining is used.
If the mold cavity has a large, flat bottom surface, rough machining is done with a one-piece milling disc followed by corner clearing with a round-nose milling cutter, which has good cutting strength and disperses heat. Round nose milling cutter in the processing of the need to clear
the root of the parts faster than the flat bottom cutter efficiency, not easy to collapse the edge
Second, the choice of cnc precision machining tools
When cnc precision machining hardened mold, the correct choice of milling cutter is very important. Usually, the choice of high rigidity body design, high temperature resistance, wear-resistant coating, super hard material production tool is preferred, Zhongshan Elang precision tools launched high-speed and high hardness H series to achieve high-speed and high hardness HRC70 processing. In addition, the rigidity of the tool is important, in order to increase the rigidity of the small diameter milling cutter, the diameter of the shank is made much larger than the diameter of the tool to improve the machining finish and extend the tool life; the overhang length of the tool clamping should be as short as possible. On the other hand, the choice of new coatings, so that the tool can withstand higher cutting temperatures, such as Tisin and Cygnus-X coating with acidification temperature of 1300 ℃, surface hardness Hv3700, coating thickness of 4um so they are more suitable for high-speed and hardening quenching mold processing
Third, cnc precision machining toolholder selection and tool clamping
The toolholder should be dynamically balanced or choose sintered toolholder, while the shape of the toolholder should be adapted to the structure of the mold. Usually a half degree clearance should be maintained between the milling cutter and the side of the workpiece, for example, if the side of the workpiece is 3° bevel, the shape of the toolholder is made 5/2 to get the maximum rigidity. If the side of the workpiece is 90° straight, the shank should be of thin neck construction.
It is important to clamp the milling cutter, which involves the tolerance of the toolholder, the fit of the toolholder and the tool holder, and the diameter jump after installation. For this reason, the manufacturing tolerance of the toolholder should be -0.0025mm to -0.005mm, or the application of heat shrinkable clamping to clamp the tool.
Fourth, nc precision machining machine selection and NC programming points
The use of good rigidity, high precision machine tools to achieve good results. Machining high hardness mold programming tool cutting into the mold path should be used spiral interpolation, so that the cutting process is smoother. In cases where cutting from the side or spiral cannot be used, oblique wave cutting should be used to avoid axial cutting. Programming also determines the size of the radial travel and depth of cut.