Design principles of the hottest green cutting too

2022-08-17
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Green manufacturing is an important part of the sustainable development strategy of human society. Its basic purpose is to make the product have the highest resource utilization rate, the least waste and the least negative impact on the environment in the whole life cycle from design, manufacturing, use to scrap disposal. Machining plays an important role in the manufacturing industry. While it creates wealth for human society, the enterprise no longer produces metallurgical coke. It is also consuming a lot of limited natural resources and causing environmental pollution. As one of the indispensable elements of cutting, cutting tools also have problems of resource utilization and environmental protection in their manufacturing and use. Therefore, people put forward the concept of green cutting tools and applied it to the design, manufacture and use of cutting tools

1. Basic characteristics of green cutting tools

according to the guiding ideology of green manufacturing "saving energy, using resources, reducing pollution and conducive to environmental protection", green cutting tools should have the following characteristics:

(1) saving energy to the greatest extent: the recycling amount of green cutting tools in their production and recycling enterprises is also small, and the energy consumed in each stage of the life cycle should be the least, so that the energy can be used most effectively

(2) maximize the use of material resources: Green tools should minimize the amount and types of materials used (less or no rare materials and toxic and harmful materials), which requires that when designing tools, on the premise of meeting the "cutting" requirements, the tool structure should be simplified as much as possible, the materials should be used reasonably, and the reuse of tool materials can be realized to the greatest extent

(3) minimize pollution and protect the environment: green cutting tools should have no negative impact or little pollution on the environment in all processes from development and design, production and manufacturing, use and maintenance, and even recycling after scrapping

2. Green tool life cycle design system

the green design of cutting tools is different from the traditional design method. Green design includes conceptual design, technical design, production, manufacturing and process, use and maintenance, recycling after scrapping, reuse and treatment of the whole process, "green points out that the dashboard materials need to be environmentally friendly (low volatility, bio based materials); lightweight (low density of foaming technology, high activity of thin wall technology); comfort (ultra soft touch, multi-color and multi texture, lighting technology)", that is, the life cycle design of green tools. The key point of green design is to comprehensively consider the negative impact of cutting tools (products) on the process environment in the design process, and control it within the minimum range or completely eliminate it. Therefore, a green tool life cycle design system model can be established. The system model consists of four levels. The first layer is the target layer, aiming to design green cutting tools that "use resources, save energy, reduce pollution and protect the environment"; The second layer is the content layer, including four parts: the technical structure design of green cutting tools, the selection of green materials, the utilization of resources and energy, and the protection of ecological environment; The third layer is the process layer, that is, the main stages of development and design, production and manufacturing, use and maintenance, recycling and treatment that should be considered to realize the content of green design; The fourth layer is the factor layer, that is, the main factors that should be considered in the process of green design, including materials, energy, cost, efficiency, safety, processing quality, service life, environmental impact, etc

3. Key points of green tool design

3.1 basic requirements of green tool technology design

at present, green cutting technology is mainly dry cutting and high-speed cutting. The technical design of green tools should meet the following basic requirements:

(1) in order to meet the requirements of dry cutting and high-speed cutting on the cutting performance of tools, green tool materials should have high strength, high hardness, good heat resistance, impact toughness and other mechanical and physical properties. Some existing cutting tool materials, such as ceramics, CBN, high-performance cemented carbide, have good heat resistance and wear resistance, which can be used in the manufacture of green cutting tools

(2) dry cutting and high-speed cutting will significantly increase the temperature of the cutting area, increase the friction resistance between the tool and the chip, easily produce chip nodules, and aggravate tool wear. In order to improve the high temperature resistance and wear resistance of the cutting edge of the tool, the surface of the tool can be properly coated (such as tin, tic, Al203 and other coatings), so as to reduce the cutting force and cutting power, reduce the friction resistance between the tool and chips, block the cutting heat, reduce the wear of the tool, and prolong the service life of the tool

(3) chip removal and heat dissipation are important technological issues to be solved in dry cutting and high-speed cutting. In order to improve the processing quality and prolong the tool life, the chip removal groove structure of green tools should be optimized to ensure smooth chip removal and rapid heat dissipation

3.2 design characteristics of geometric parameters of green cutting tools

(1) dry cutting tools

during dry cutting, because the temperature at the contact part between the tool and chips is too high, the wear mechanism of the tool is usually crescent wear. In general, the dry cutting tool should have a large rake angle, but increasing the rake angle will reduce the strength of the tool tip. Therefore, a suitable negative chamfer can be set to make the cutting edge have sufficient bearing capacity to the cutting force and cutting high temperature. At the same time, it can reduce the cutting impact and the adverse effects caused by the expansion of crescent depressions, so that the cutting edge can maintain sufficient strength for a long cutting time. In addition, properly increasing the rake angle, rake angle and blade inclination angle of the tool tip can shorten the contact length between the tool and the machined surface, which is conducive to reducing the wear of the back tool surface and extending the service life of the tool

(2) high speed cutting tool

high speed cutting has the advantages of small cutting force, rapid heat dissipation, stable machining process and so on. Compared with ordinary cutting tools, high-speed cutting tools have smaller rake angle (about 10 °) and larger rake angle (about 5 ° ~ 8 °). In order to prevent thermal wear at the tool tip, the method of tool tip rounding or chamfering can be adopted at the joint of the main and auxiliary cutting edges. By increasing the tool tip angle, increasing the cutting edge length and tool material volume near the tool tip, the tool rigidity can be improved and the probability of tool edge damage can be reduced. In addition, for high-speed rotary tools (including tool handle and tool rotating assembly), precise dynamic balance verification should also be carried out to ensure processing quality and processing safety, prolong tool life and improve cutting efficiency

The development trend of green cutting technology shows that the organic combination of dry cutting and high-speed cutting will obtain multiple benefits, such as high production efficiency, good processing quality and low environmental pollution

4. Conclusion

in order to achieve the overall goal of the design of the life cycle of the cutting tool with the compressive capacity of the green compact specimen and its height H0, the whole design process should be carried out with "greening" as the main line from the conceptual design of the cutting tool, including the selection of green materials, the adoption of green manufacturing technology and process in the production and manufacturing process, and the application of green cutting technology by users in use, which will not produce environmental pollution or minimize the pollution, In the process of recycling and disposal of scrapped and obsolete tools, green treatment technology is used to minimize waste without secondary pollution, so as to realize the "greening" of the whole life cycle of tools. (end)

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