A Brief Discussion on Metal Stamping Dies in the Mold Industry

Entering the 21st century, fierce market competition is driving advanced manufacturing technology led by machine manufacturing technology to develop at an unprecedented speed, and the manufacturing of aviation components has also entered a development period characterized by digital manufacturing technology. According to the editor of Huicong Surface Treatment Network, advanced aviation products require aviation parts to have better performance, lower cost, and higher environmental friendliness, while processing technology requires faster processing speed, higher reliability, high repeatability, and reproducibility. Traditional cutting tools can no longer meet the above requirements, and the cutting tool industry has entered a new pattern of modern cutting tool production characterized by "high precision, high efficiency, high reliability, and specialization".
High speed and efficient cutting
With the advancement of science and technology, we are in a period of rapid development of advanced manufacturing technology. The promotion and application of CNC machine tools have greatly reduced the auxiliary time for part processing and greatly improved productivity. In the total working hours of aviation parts processing, as the auxiliary time is shortened, the proportion of cutting time increases accordingly. To further improve the productivity of machine tools, it is necessary to significantly increase the cutting speed, which is also the main reason for the rapid development of high-speed cutting technology in recent decades. High speed machining has been mainly used for the processing of light alloys in the aviation industry, and has now become the main way for the aviation manufacturing industry to improve processing efficiency and quality, and reduce processing costs.
High speed cutting is being widely used in the processing of aviation components, mainly for the following reasons:
(1) In order to achieve maximum weight reduction and meet other requirements, many components, wall panels, etc. adopt the "integral manufacturing method", which removes excess on large blanks to form thin-walled and fine ribbed parts. A large amount of metal material needs to be removed, resulting in cutting time occupying a large proportion of the total production time of the parts. Therefore, one of the ways to improve productivity is to use high-speed cutting processing.
(2) The structure of aircraft parts is complex and high-precision, and the thin-walled and fine rib structures of the parts have poor stiffness. It is necessary to minimize the radial cutting force and thermal deformation during processing, and only high-speed cutting can meet these requirements.
(3) Difficult to machine materials such as nickel based high-temperature alloys, titanium alloys, and high-strength structural steels are widely used in modern aviation products. These materials have high strength, hardness, impact resistance, are prone to hardening during processing, high cutting temperatures, and severe tool wear, making them difficult to machine materials. Generally, very low cutting speeds are used for machining. If high-speed cutting is used, it can not only significantly improve productivity but also effectively reduce tool wear and improve the surface quality of parts.
High speed cutting has different machining mechanisms and application advantages from traditional cutting techniques, and it is a transformation of the concept of CNC machining technology. According to the material and structural characteristics of aviation products, advanced high-speed cutting tools must be used to ensure high-speed machining. High speed cutting tools must have good wear resistance and high strength toughness, advanced tool materials, excellent tool coating technology, reasonable geometric structure parameters, highly dynamically balanced tool systems, safe and reliable clamping methods, as well as high concentricity blade accuracy, and so on.
The Development Direction and Application of Cutting Tools and Cutting Materials
At present, in the field of aircraft manufacturing, high-speed steel cutting tools account for about 6% of the total cutting tools, hard alloy cutting tools account for about 35% of the total cutting tools, and superhard cutting tools (cubic boron nitride, diamond) account for no more than 5% of the total cutting tools. In the future, with the continuous emergence of new aviation materials and the increasing application of hard cutting and dry cutting, the proportion of hard alloy cutting tools, coated cutting tools, ceramic cutting tools, cubic boron nitride cutting tools, and polycrystalline diamond cutting tools will be significantly increased.
1. Development of Hard Alloy Materials
In order to meet the rapid development of high-speed cutting technology, the performance of various cutting tool materials, mainly hard alloys, has been comprehensively improved. The development of fine and ultrafine particle hard alloys and the application of coating technology in hard alloy cutting tools have significantly improved the strength and toughness of hard alloy materials. Solid alloy cutting tools manufactured with them are gradually replacing traditional high-speed steel cutting tools, which has increased cutting speed and processing efficiency several times, laying an important foundation for the promotion and application of high-speed cutting. Solid hard alloys have also been applied in some complex forming tools, meeting the demand for product processing diversity. At present, Xiamen Jinlu Special Alloy Co., Ltd., Zhuzhou Diamond Hard Cutting Tools Co., Ltd., Siping Bolt Process Equipment Co., Ltd., and Shaanxi Aviation Hard Alloy Tools Co., Ltd. can all provide hard alloy cutting tools for the aviation industry in China, and their product performance is close to the world's advanced level.
In the 21st century, the development of hard alloy cutting tool materials should focus on two aspects: firstly, refining the grain size to reach the nanometer level microcrystalline level. The smaller the grain size of cemented carbide, the higher its hardness, wear resistance, toughness, and stiffness, thereby expanding its application range; The second is to apply new technologies and processes to develop new types of hard alloys to improve their intrinsic properties and quality.
2. Development of Coating Technology
Tool coating technology plays a very important role in modern cutting and tool development. Since its inception, it has developed rapidly, especially in recent years when significant progress has been made. Chemical coating (CVD) is still the main coating process for reversible inserts. New processes such as medium temperature CVD, thick film alumina, and transition layer have been developed successively. On the basis of improving the substrate material, the wear resistance and toughness of CVD coatings have been improved; Significant breakthroughs have also been made in physical coating (PVD) technology, with significant progress made in the structure, process, and automatic control of coating equipment. Coatings with better heat resistance have been developed to adapt to high-speed cutting, dry cutting, and hard cutting. Through innovation in coating structures, a large number of new coatings such as nano and multi-layer structures have been developed, greatly improving the hardness and toughness of coatings.
3. Development of superhard cutting tool materials
Superhard materials refer to diamond and cubic boron nitride (CBN), whose hardness is several times higher than other tool materials. Diamond is a hard substance in nature, and CBN's hardness is second only to diamond. In recent years, the development of superhard cutting tool materials has been rapid.
Diamond cutting tool materials are divided into five categories: natural diamond (ND), synthetic polycrystalline diamond composite (PCD/CC), diamond thin film coated cutting tools (CD), diamond thick film cutting tools (FCD), and synthetic polycrystalline diamond (PCD). The crystal anisotropy of ND requires the selection of an appropriate direction for the use of knife grinding; Artificial diamond is isotropic, with lower hardness than ND, but better strength and toughness than ND.
Diamond cutting tools can effectively process non-ferrous and non-metallic materials. Non ferrous metals and their alloys such as copper and tungsten, ceramics, hard alloys, various fiber and particle reinforced composite materials, plastics, rubber, graphite, glass, and wood, but diamond should not cut steel and other iron group elements.
Cubic boron nitride (CBN) cutting tool material has extremely high hardness and red hardness, making it an ideal tool material for high-speed precision machining or semi precision machining of quenched steel, chilled cast iron, and high-temperature alloys. Due to the good surface roughness that CBN cutting tools can achieve when machining high hardness parts, cutting quenched steel with CBN cutting tools can achieve "cutting instead of grinding".
4. Development of high-speed steel materials
In the future development of cutting tool materials, the development of high-speed steel materials should still be mentioned. Although the sales of high-speed steel materials worldwide are decreasing year by year, the use of high-performance cobalt high-speed steel and powder metallurgy high-speed steel is still increasing. These two types of high-performance high-speed steel have better wear resistance, red hardness, and reliability than ordinary high-speed steel. With the improvement of people's pursuit of cutting efficiency and the change of concepts, these high-performance high-speed steel cutting tools are widely used in the aviation field. For processing materials in aviation accidents, high-precision composite cutting tools for drilling, expanding, reaming, and countersunking are used on automatic drilling and riveting machines, as well as various composite cutting tools for processing complex surfaces of aircraft parts.
With the advancement of technology, advanced manufacturing systems, the development and implementation of high-speed cutting, ultra precision machining, and green manufacturing, new requirements have been put forward for cutting tools, and there will be significant development in cutting tool materials in the future. The alternating development and mutual promotion between tool materials and workpiece materials have become the historical law of the continuous development of cutting tools. In the future, tool materials will inevitably face more severe challenges such as improving workpiece performance, increasing processing batches, and improving manufacturing accuracy. The progress of materials science has promoted the development of cutting tool materials, and the development of cutting tool materials should consider the constraints of raw material resources. The emergence of new varieties, changes in the proportion of new and old varieties, and the pattern of competition and complementarity between them will become new characteristics of the future development of cutting tool materials.