Curved surface parts and curved tooling tools are the types of workpieces that are very suitable for processing by machining centers. In the industrial field, curved surface parts are also widely used, such as turbine blades, ship propellers, industrial products with cylindrical and conical surfaces, and so on. When performing CNC machining on curved surfaces, CNC milling is generally used. What aspects should be paid attention to when milling surfaces? What should a complete surfacing process look like?
CNC machining of curved surface parts also follows the machining rules of CNC machining centers, that is, rough machining (rough opening)-semi-finishing-finishing-detail processing. Since the free-form curve and surface cannot be clearly expressed by geometric drawing and mechanical drawing, it has become the primary problem to be solved in the roughing stage of the machining center.
Open rough
In order to improve the efficiency of CNC milling when performing preliminary processing on the blanks of curved surface parts, the end mill can be used to mill layer by layer according to the contour surface according to the allowance given by the processed curved surface. After rough milling, the shape of the curved surface will be distributed in layers, and the height of the steps depends on the rough milling accuracy. During rough machining, due to the large machining allowance and cutting amount of CNC, a large amount of cutting heat is generated during the cutting process, which is easy to cause rapid wear of the tool. At this time, the temperature of the cutting area should be lowered. to lubrication and cooling.
Semi-rough machining
Semi-roughing is essential, which is an important stage from roughing to finishing, and its purpose is to mill out the excess parts left in the roughing step. Semi-finish milling should be carried out with a ball end milling cutter, and its line spacing and step distance should be larger than that of fine milling. It should be noted that semi-finish milling should leave a CNC machining allowance of about 0.5 mm for the subsequent fine milling process. After this process, the shape of the machined surface is close to the theoretical surface.
The tool for CNC machining curved surface parts is mainly a ball end milling cutter
Ball end milling cutter
The material of the ball end milling cutter is mostly high-speed steel. Due to the structure and the way of movement, the cutting speed of the ball end milling cutter at the tip is very low. When using a ball end milling cutter to mill a gentle curved surface perpendicular to the machined surface, the quality of the surface cut out by the tool tip will be relatively poor. Therefore, try not to cut with the tip of the tool as much as possible, and increase the spindle speed appropriately.
The processing of CNC parts with complex curved surfaces and different surfaces is an important manifestation of the degree of numerical control, and it is also a standard for testing the processing performance of CNC machining centers. If you have any questions about CNC milling surface parts, welcome to discuss growth with CNCMF!