(II) Development trend of cutting technology

From the development history of the tool, from the end of the 19th century to the middle of the 20th century, the tool material was mainly represented by high-speed steel; in 1927, Germany first developed the cemented carbide tool material and was widely used; in the 1950s, Sweden and the United States Synthetic diamonds are separately synthesized, and the cutting tools are stepped into a period represented by superhard materials. In the 1970s, people used high-pressure synthesis technology to synthesize polycrystalline diamond (PCD), which solved the problem of rare and expensive natural diamonds, and extended the application range of diamond tools to aviation, aerospace, automotive, electronics, stone, etc. Multiple areas.

The choice of tool material is the basis for successful machining. Compared to cemented carbides, PCD cutters can reach speeds of up to 4000 m/min, while cemented carbides have only 1/4 of them. In terms of life, PCD tools can generally be increased by 20 times. From the surface quality of the processed, the effect of PCD is 30% to 40% better than that of cemented carbide. In addition, the development of CBN (Nbright Boron Nitride) superhard material tools and surface coating tools has also contributed to the advancement of cutting technology.

For more than 100 years, the cutting speed of cutting tools has been continuously improved, which has brought about changes in processing efficiency, which has further expanded the processing range. The biggest mark of the development of cutting processing is the development of high speed cutting (HSC).

A high-speed machining system involves many aspects. From the processing point of view, the traditional cutting process, a workpiece (such as mold), through the blank annealing - roughing - finishing - quenching - EDM preparation - EDM - special finishing - manual polishing procedures . High-speed machining only requires blank quenching-roughing-semi-finishing-finishing and super-finishing. It is reduced by three steps, and the processing time is shortened by 30%~50% compared with the traditional processing method. This advantage is especially noticeable when it comes to small parts. What's more, in the past, some companies used to make complex molds, which basically took 3 or 4 months to be delivered. After high-speed cutting, it only took half a month to complete.

A high-speed machining system consisting of two parts: tool and technology. The factors associated with the tool are the choice of tool material, the composition of the tool system, and the shape of the edge to be machined. Closely related to the technology is the choice of CAD / CAM system, the planning of the tool processing path, the setting of cutting parameters and the cooling and lubrication links.

Since the popularization of high-speed cutting, the processing efficiency has increased by 4 to 5 times in the half century from 1950 to 2000. Of course, it should be mentioned that high-speed cutting generally defines its "high speed" range from its processed objects.

The proportion of the tool in the total processing cost is not large. We take the manufacturing process of the automobile industry as an example: the investment in machine tools and other equipment accounts for 35% of the total cost, the energy consumption of the equipment accounts for 7%, the normal operating cost of the enterprise accounts for 27%, and the cooling and lubrication costs account for 17%. Labor accounts for 9% and tools account for 4%. Coincidentally, in the mass production cost of machine tool aluminum alloy workpieces, cooling and lubrication accounted for 16%, tools 4%, and other processing costs accounted for 80%. It can be seen that the tool only accounts for a very small part of the total cost. However, it should not be overlooked that this 4% cost tool may affect the overall processing efficiency of 10% to 15%.

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