High-speed milling technology applied in plastic mold processing

At present, plastic molds are becoming more and more sophisticated, structures are becoming more and more complex, and the entire pair of molds is becoming more and more precise. The number of molds required for molds is close to and exceed 800,000 times. The hardness of mold steels used by foreign plastic mold manufacturers is getting higher and higher. Some even exceed HRC 64, and the delivery time of the mold is getting shorter and shorter. These market characteristics have put tremendous pressure on mold manufacturers. The emergence of high-speed milling technology has brought new development opportunities for mold manufacturing, especially in the processing of small and medium-sized precision plastic molds.

Reduce the number of processes in plastic mold processing and shorten the delivery time of molds

The high efficiency of high-speed cutting is not only reflected in how much machine processing time is reduced, but actually reduces overall process time. Higher cutting speeds, less machining allowance for finishing, denser rails and less depth of cut, especially on free-form surfaces (cutting depths are typically 0.02 to 0.1 mm, such as using small tool diameters) For a 0.3-0.8mm diameter tool, the depth of cut is as small as (0.008-0.02mm). Fine, tight tool rails generally improve the finish of the machined surface. Replace the conventional slow weight with fast and fine light cutting. Cutting will greatly simplify the subsequent processes. For example, manual polishing time can be shortened by 60%-100%, and the process and time of EDM can be reduced. This saving has been truly reflected in many foreign mold manufacturers.

Machinable thin-walled ribs and clear roots of small diameter tools

Since the high-speed milling machine greatly improves the spindle speed and the dynamic balance of the spindle and the stability of the machine tool, a larger cutting speed can be obtained under the same tool diameter, so that a light cutting process can be realized on the surface of the tool and the workpiece. Greatly reduce the cutting force in the cutting area. Therefore, it can process thin walls or ribs of 0.1mm or more, and at the same time bring great convenience to the small rounded roots of precision molds. Even if the hardness of the mold material reaches HRC54, the cutter with diameter of 0.3mm can be used for milling operation. This greatly reduces the number of electrodes and also reduces the electrical discharge machining time.

Before the high-speed milling is used, the electrode is made by an engraving machine, and the effect is not satisfactory. It is easy to break the knife during processing, the processing efficiency is low, the finish is low, and the hardness of the processed material is low, which does not meet the requirements of foreign companies. High-speed milling greatly improves machining quality and machining efficiency.

Improve the accuracy of machined parts

Compared with the traditional cutting method, the cutting pattern of high-speed milling is different. Most of the generated heat is taken away by the chips, and the heat does not collect in the processing area. At the same time, the cutting speed is much faster than the conventional cutting speed. The heat is less likely to accumulate, and the material has much less thermal deformation, maintaining a relatively constant and ideal cutting condition, thereby ensuring the machining accuracy of the workpiece. In addition, in the electrode processing, the processed electrode has high precision, good contour shape and high smoothness, and the electrode generally does not need polishing treatment, and the precision of the workpiece is not affected by manual polishing, thereby greatly improving the manufacturing precision of the mold.

High efficiency electrode processing and more efficient electrical discharge machining

Due to the different ways of high-speed milling to produce chips and the difficulty in concentrating the processing heat, it can provide faster cutting speed when processing copper electrodes and graphite electrodes. The material removal rate per unit time is several times higher than that of conventional cutting. The time for roughing and semi-finishing of the electrode is greatly shortened, and high-speed light cutting is adopted in the finishing process, and the finer and more precise tool rail greatly improves the smoothness of the electrode, saving or even eliminating the polishing time. In the processing of graphite electrodes with very large tool wear, the use of PCD (diamond) coated tools greatly reduces the wear of the tool, making high-speed milling possible in the processing of graphite electrodes.

In the electric discharge machining process, coarse and fine electrode processing is generally used at present, and the high-speed cutting electrode reduces or eliminates the polishing work, so that the discharge area of ​​the electrode is uniform, the surface contact is improved, the discharge gap is effectively controlled, and the discharge efficiency is improved. . At the same time, since a smaller tool diameter can be used, the machining allowance of the mold is reduced, so that the coarse electrode can be eliminated, the number of electrodes is reduced, and the time of electric discharge machining is shortened.