The main process of precision machining includes three kinds, namely soft machining, hard machining and electric machining.
precision machining
First, cnc precision machining sequence
When the die is very large and deep, soft machining is used for rough machining and semi-finishing machining before quenching, and hard machining is used for finishing machining after quenching; Small, shallow molds can be milled in one go after quenching. If the die wall is very thin and the die cavity is very deep, electrical machining is used.
If the cavity has a large and flat bottom surface, then after rough machining with the integrated milling cutter, the use of round nose milling cutter to clear the Angle, the cutting force of the integrated milling cutter and the effect of heat dispersion is very good. Round nose milling cutter in the machining need to clear the root of the part of the efficiency is faster than flat knife, not easy to break the edge
Two, cnc precision machining tool selection
It is very important to select milling cutter correctly when cnc precision machining with hard die. Usually, it is a good choice to choose the tool with high rigidity tool body design, high temperature resistance, wear-resistant coating and super hard material production. The H series with high speed and high hardness introduced by Zhongshan Airang Precision tool realizes the processing of high speed and high hardness HRC70 below. In addition, the rigidity of the tool is very important, in order to increase the rigidity of the small diameter milling cutter, the diameter of the tool handle is much larger than the diameter of the tool, in order to improve the machining finish and extend the life of the tool; The overhang length of the tool clamp should be as short as possible. On the other hand, new coatings are selected to enable the tool to withstand higher cutting temperatures. For example, the acidizing temperature of Tisin and Cygnus-X coatings is 1300℃, the surface hardness is Hv3700, and the coating thickness is 4um. Therefore, they are more suitable for high-speed and hardening mold processing
Three, cnc precision machining tool handle selection and tool clamping
The tool handle should have dynamic balance or choose the sintered tool handle, and the shape of the tool handle should adapt to the structure of the die. Generally, a half degree clearance should be maintained between the milling cutter and the side of the workpiece. For example, the side of the workpiece is a 3 degree inclined plane, and the shape of the shank is made into 5/2 to obtain great rigidity. If the side of the workpiece is 90° face, the shank should be of fine neck construction.
Clamping milling cutter is very important, which involves the tolerance of the tool handle, the fit of the tool handle and the tool clip, the diameter jump after installation and other factors. For this purpose, the shank shall be manufactured to a tolerance of -0.0025mm to -0.005mm, or the tool shall be held with a heat shrink clamp.
Four, the selection of nc precision machining machine tools and NC programming points
The use of good rigidity, high precision machine tools to achieve good results. When machining high hardness mold programming, the path of cutting tool into the mold should adopt spiral interpolation, so that the cutting process is stable. In the case that can not be used from the side or spiral cut in, should be used oblique wave cut, avoid axial cut. The programming also determines the radial cutting tool size and cutting depth.