There has always been a voice in the mold industry that high-speed milling will replace EDM. In fact, these two technologies have their own advantages and disadvantages, and the appropriate equipment should be selected according to their own processing needs.
1. Can the development of high-speed milling replace EDM?
It can be said that EDM and high-speed milling are the two main forces of mold forming processing technology, and they have their own advantages. With the rapid development of high-speed milling technology, can its development trend replace EDM?
Objectively speaking, high-speed milling technology is not omnipotent. It originated from the supplement of the weaknesses of traditional milling and EDM processes. Its mature development has gradually broadened its application field, but due to the constraints of the characteristics of the milling method itself, it is impossible to replace EDM in mold processing.
2. Advantages and applications of EDM
In general, the advantages of EDM are mainly reflected in the processing of deep grooves and narrow slits, the processing of internal clear angles, the processing of clear edges, the processing of subtle, complex, precision processing, and the processing of deep cavities, as well as the processing of superhard materials, which are all the shortcomings of high-speed milling processing capabilities. It can be seen that in the manufacture of precision molds with subtle and complex shapes, EDM has an absolute advantage.
With the rapid development of high-speed milling technology, the demand for rough and medium processing types of EDM has been significantly reduced. However, in the face of challenges, EDM has integrated advanced CNC technology. The advancement of technology has enabled various process indicators to reach a high level, and can obtain micro-cavities with highly precise edges and corners, and can obtain mirror processing effects with Ra values less than 0.1 microns. In addition, technologies such as EDM CNC milling and large-area fine processing of mixed powder EDM have also expanded the application scope of EDM.
For the processing of precision small cavities, narrow slits, grooves and corners, EDM should be the first choice of process; for the processing of complex shapes, especially when the tool is difficult to reach the complex surface, EDM has its significance; where deep cutting is required and where the aspect ratio is particularly high, high-speed milling should be avoided more clearly; for the processing of high-tech parts, the programming time of the general processing electrode is shorter than the time of high-speed milling workpiece, and this difference becomes more obvious in more complex processing applications; where EDM finishing is required, EDM is used to provide spark pattern surface.
It is worth mentioning that there are many processing situations that can be completed by high-speed milling in theory. But in fact, due to the high cost of fine tools and the risk of milling high-hardness steel parts, EDM is more likely to achieve the expected effect.
3. Advantages and applications of high-speed milling
High-speed milling uses small-diameter milling cutters, high speeds, and small cycle feeds, which greatly improves production efficiency and processing accuracy. At the same time, due to low milling force, reduced thermal deformation of the workpiece, and fast feed due to small milling depth, the surface roughness of the processing is very small.
High-speed milling is suitable for the processing of most molds. In mold processing, high-speed milling can process 60HRC hardened steel parts. Therefore, high-speed milling allows cutting after heat treatment, which greatly simplifies the mold manufacturing process. The traditional processing steps are: rough machining of the shape → rough milling of the cavity → heat treatment → finishing of the shape → EDM machining of the cavity → bench grinding and polishing of the cavity → surface strengthening treatment. The process after high-speed machining is: rough machining of the shape → heat treatment → finishing of the shape → high-speed milling of the cavity → surface strengthening treatment, which can save electrical machining (relatively speaking) and manual grinding processes, shorten the process route, and greatly improve the processing productivity.
In general, high-speed milling should be used as much as possible to replace EDM for large removal processing. When the tool is easy to approach the workpiece, the shape of the processing part is open, and the aspect ratio is small, it is suitable for high-speed milling.
In fact, high-speed milling is very suitable for the manufacture of electrodes. The electrodes of traditional milling need to be polished manually, and the consistency is poor, which will affect the quality of EDM. The electrodes processed by high-speed milling almost do not need manual polishing, and the roughing and finishing electrodes can achieve almost perfect consistency. At the same time, high-speed milling can process thin-walled and more complex electrodes.
However, no matter how high-speed milling develops, it is limited by its mechanism. Even if five-axis machining with a rotating tool is used, it still cannot produce a clear-angle shape. For deep cavities and narrow grooves, the effect is not ideal due to insufficient tool rigidity.
4. The integration and development of EDM and high-speed milling
In today's rapid development of high-speed milling, the development space of EDM has been squeezed to a certain extent. At the same time, high-speed milling has also brought greater technological progress to EDM. For example, the use of high-speed milling to manufacture electrodes greatly reduces the number of electrode designs due to the realization of narrow area processing and high-quality surface results. In addition, using high-speed milling to manufacture electrodes can also improve production efficiency to a new level and ensure the high precision of electrodes, which also improves the precision of EDM. If most of the processing of the cavity is completed by high-speed milling, EDM is only used as an auxiliary means to clear corners and trim edges, so that the allowance is more uniform and less.
The development of EDM and high-speed milling is harmonious and complementary. The development of high-speed milling technology has promoted the development of EDM technology and also provided it with new development momentum. They have irreplaceable roles, and both should play their strengths and avoid their weaknesses. The combination of these two technologies can provide a perfect processing solution for the manufacture of highly complex and high-precision molds.
