Diamond tools have excellent adaptability in the processing of non-ferrous metals and wear-resistant materials.
Among the tool materials, diamond is the hardest. Under suitable processing conditions, diamond has a longer service life than high speed steel, cemented carbide, ceramic, and polycrystalline cubic boron nitride. It also has the disadvantage that it is generally not suitable for the processing of ferrous materials. But in high-speed, high-volume production, diamonds are often the most effective tool for processing materials such as aluminum and graphite.
When using diamond tools, users have two options: one is polycrystalline diamond (PCD) and the other is newer chemical vapor deposition (CVD) diamond.
The use of performance has long been proven. Polycrystalline diamond has the hardness, strength and abrasion resistance of natural diamond, but there is no sensitivity of natural diamond to breakage. It is polymerized from synthetic diamond particles under high temperature and high pressure. During the process, the polycrystalline particles are simultaneously bonded to a cemented carbide substrate to improve mechanical strength and impact resistance.
According to GE's Super Abrasives Division, PCD is well suited for high-speed cutting of aluminum, especially for applications where good surface roughness is required. It also exhibits excellent performance when processing highly wear resistant materials. In general, PCD is recommended for cutting high-silicon aluminum alloys and also for the processing of brass, copper, bronze and carbide. The processes used include car, boring, profiling, grooving, milling and hole machining.
Due to the chemical interaction between diamond and iron, PCD is generally not suitable for processing ferrous materials. But it can deal with the processing of bimetallic materials, including the combination of aluminum and cast iron. For example, when an auto parts supplier processes aluminum and cast iron bimetal cylinder blocks, it uses a 305mm diameter face-to-face face milling cutter with a 2.36mm tool nose and a light-cutting knife. The cutting speed is 304.8m/min and the feed is 0.10. Mm/tooth, cutting depth 5mm, after processing 5000 cylinders, the blade needs to be indexed once.
GE's application planning manager believes that the application of PCD has been driven by the mass production industry, mainly the automotive industry's increasing processing speed of aluminum parts. At the same time, in order to reduce weight and reduce costs, automakers are evaluating composites using metal substrates that are processed using PCD. He said: "This type of material cannot be machined with carbide tools."
The production manager of polycrystalline products said that although the development achievements of PCD have been very impressive, GE Super Abrasives continues to work to further improve its anti-wear properties.
PCD tools bring many benefits to the process in terms of application and productivity. Although diamond is the hardest among existing materials, problems such as material properties and toughness still need further study. One factor that improves the toughness of the PCD is the addition of cobalt to the randomly unaligned diamond grains. In addition, the cemented carbide substrate can also mechanically support the diamond abrasive layer, thereby increasing the impact resistance and facilitating brazing in tool manufacturing.
Another benefit of PCD is that the existing range of grades is sufficient for any non-ferrous metal processing needs. In general, fine-grained diamond is used in applications where the wear resistance of the material to be processed is low and the surface roughness is very high; medium-grain diamond is generally used as a general grade for machining; coarse-grained diamond is used for roughing and is particularly resistant to abrasion. Material, but the surface roughness is not high.
A new member of the diamond family Chemical vapor deposition (CVD) diamond is a high-wear, pure diamond material that contains no binder. Diamond deposits come in two forms: a thick film of diamond, deposited as a unitary, individual sheet, and then cut to the desired size; and a thin film of diamond deposited on a carbide insert or rotary cutter.
To date, the most promising use of CVD diamonds has been in the processing of graphite. However, Norton Diamond Film is selling CVD diamonds for a variety of applications in the processing of non-ferrous metals, plastics and composites. Norton's application technology manager believes that CVD diamond is suitable for almost all non-ferrous metals. Good results are being achieved in the interrupted cutting of high silicon aluminum alloys and in the processing of pre-sintered cemented carbide, brass, copper and carbon fiber materials. Norton also believes that CVD diamonds can compete with PCD when processing a wide range of aluminum alloy materials, including 6061 and others.
Norton's application technology manager also believes that the main advantage of CVD diamond compared to PCD is the quality of the cutting edge. Although CVD is also polycrystalline, it does not contain a cobalt binder and is pure diamond, so the cutting edge is continuous. This allows for a higher cutting speed and better surface roughness because the tool does not heat up. He also firmly believes that built-up edge does not pose a problem for CVD diamond.
According to Norton, the thermal conductivity of CVD diamond is 50% higher than that of PCD. The reason is that the CVD blade is a monolithic diamond that can be used to conduct heat immediately. The thermal conduction of the PCD blade passes through the cobalt-diamond composite, and the thermal conductivity is worse.
CVD diamond also has a lower coefficient of friction. Both cemented carbide and PCD bond the workpiece material, while CVD diamond is not sticky. At the same time, the low coefficient of friction also allows CVD diamond tools to withstand large cutting loads, making cutting faster and more efficient.
CVD diamond exhibits thermal and chemical stability in use. PCD and cemented carbide are affected by the inclusion of a metal component binder in this respect. Putting the CVD diamond into hydrochloric acid will not happen. However, if the PCD diamond is put in, the acid will eat the cobalt binder. This means that CVD diamond can withstand the attack of certain materials during the processing of acid, such as phenolic resin, urethane rubber, carbonate lowers and the like.
While all forms of diamond (including PCD) chemically react with some components of ferrous or superalloys at elevated temperatures, it is well known that diamond is still chemically inert to most materials. Since PCD and cemented carbide contain a cobalt binder, chemical stability is lowered when the cutting temperature is high. This phenomenon is avoided by the fact that CVD diamond does not contain a binder. In addition, CVD diamond has good lubricity and thermal conductivity, giving it a key advantage in high speed and dry cutting.
The last advantage of CVD diamond is that it maintains high hardness and wear resistance even at high cutting temperatures. Nagy, Norton's application technology manager, said: "Because there is no soft cobalt wrapped in diamond, the hardness of the blade is uniform."
Bright prospects GE's Super Abrasives and Norton DiamondFirm believe that many production sites do not take full advantage of diamonds. The reason is that the speed and torque of many machine tools are not enough to ensure the high efficiency of the tool.
In addition to the mechanical problems, there is a difficult problem to convince the people in the production plant not to focus on the initial price of diamond (PCD or CVD diamond), but to see the cost savings and performance improvements it brings. benefit. You can increase the throughput by allowing diamonds to run at higher speeds than conventional tools (depending on machine performance). At the same time, the number of tool changes is also small. Assuming that diamonds are 50 to 100 times longer than cemented carbides, you don't have to shut down often.
Among the tool materials, diamond is the hardest. Under suitable processing conditions, diamond has a longer service life than high speed steel, cemented carbide, ceramic, and polycrystalline cubic boron nitride. It also has the disadvantage that it is generally not suitable for the processing of ferrous materials. But in high-speed, high-volume production, diamonds are often the most effective tool for processing materials such as aluminum and graphite.
When using diamond tools, users have two options: one is polycrystalline diamond (PCD) and the other is newer chemical vapor deposition (CVD) diamond.
The use of performance has long been proven. Polycrystalline diamond has the hardness, strength and abrasion resistance of natural diamond, but there is no sensitivity of natural diamond to breakage. It is polymerized from synthetic diamond particles under high temperature and high pressure. During the process, the polycrystalline particles are simultaneously bonded to a cemented carbide substrate to improve mechanical strength and impact resistance.
According to GE's Super Abrasives Division, PCD is well suited for high-speed cutting of aluminum, especially for applications where good surface roughness is required. It also exhibits excellent performance when processing highly wear resistant materials. In general, PCD is recommended for cutting high-silicon aluminum alloys and also for the processing of brass, copper, bronze and carbide. The processes used include car, boring, profiling, grooving, milling and hole machining.
Due to the chemical interaction between diamond and iron, PCD is generally not suitable for processing ferrous materials. But it can deal with the processing of bimetallic materials, including the combination of aluminum and cast iron. For example, when an auto parts supplier processes aluminum and cast iron bimetal cylinder blocks, it uses a 305mm diameter face-to-face face milling cutter with a 2.36mm tool nose and a light-cutting knife. The cutting speed is 304.8m/min and the feed is 0.10. Mm/tooth, cutting depth 5mm, after processing 5000 cylinders, the blade needs to be indexed once.
GE's application planning manager believes that the application of PCD has been driven by the mass production industry, mainly the automotive industry's increasing processing speed of aluminum parts. At the same time, in order to reduce weight and reduce costs, automakers are evaluating composites using metal substrates that are processed using PCD. He said: "This type of material cannot be machined with carbide tools."
The production manager of polycrystalline products said that although the development achievements of PCD have been very impressive, GE Super Abrasives continues to work to further improve its anti-wear properties.
PCD tools bring many benefits to the process in terms of application and productivity. Although diamond is the hardest among existing materials, problems such as material properties and toughness still need further study. One factor that improves the toughness of the PCD is the addition of cobalt to the randomly unaligned diamond grains. In addition, the cemented carbide substrate can also mechanically support the diamond abrasive layer, thereby increasing the impact resistance and facilitating brazing in tool manufacturing.
Another benefit of PCD is that the existing range of grades is sufficient for any non-ferrous metal processing needs. In general, fine-grained diamond is used in applications where the wear resistance of the material to be processed is low and the surface roughness is very high; medium-grain diamond is generally used as a general grade for machining; coarse-grained diamond is used for roughing and is particularly resistant to abrasion. Material, but the surface roughness is not high.
A new member of the diamond family Chemical vapor deposition (CVD) diamond is a high-wear, pure diamond material that contains no binder. Diamond deposits come in two forms: a thick film of diamond, deposited as a unitary, individual sheet, and then cut to the desired size; and a thin film of diamond deposited on a carbide insert or rotary cutter.
To date, the most promising use of CVD diamonds has been in the processing of graphite. However, Norton Diamond Film is selling CVD diamonds for a variety of applications in the processing of non-ferrous metals, plastics and composites. Norton's application technology manager believes that CVD diamond is suitable for almost all non-ferrous metals. Good results are being achieved in the interrupted cutting of high silicon aluminum alloys and in the processing of pre-sintered cemented carbide, brass, copper and carbon fiber materials. Norton also believes that CVD diamonds can compete with PCD when processing a wide range of aluminum alloy materials, including 6061 and others.
Norton's application technology manager also believes that the main advantage of CVD diamond compared to PCD is the quality of the cutting edge. Although CVD is also polycrystalline, it does not contain a cobalt binder and is pure diamond, so the cutting edge is continuous. This allows for a higher cutting speed and better surface roughness because the tool does not heat up. He also firmly believes that built-up edge does not pose a problem for CVD diamond.
According to Norton, the thermal conductivity of CVD diamond is 50% higher than that of PCD. The reason is that the CVD blade is a monolithic diamond that can be used to conduct heat immediately. The thermal conduction of the PCD blade passes through the cobalt-diamond composite, and the thermal conductivity is worse.
CVD diamond also has a lower coefficient of friction. Both cemented carbide and PCD bond the workpiece material, while CVD diamond is not sticky. At the same time, the low coefficient of friction also allows CVD diamond tools to withstand large cutting loads, making cutting faster and more efficient.
CVD diamond exhibits thermal and chemical stability in use. PCD and cemented carbide are affected by the inclusion of a metal component binder in this respect. Putting the CVD diamond into hydrochloric acid will not happen. However, if the PCD diamond is put in, the acid will eat the cobalt binder. This means that CVD diamond can withstand the attack of certain materials during the processing of acid, such as phenolic resin, urethane rubber, carbonate lowers and the like.
While all forms of diamond (including PCD) chemically react with some components of ferrous or superalloys at elevated temperatures, it is well known that diamond is still chemically inert to most materials. Since PCD and cemented carbide contain a cobalt binder, chemical stability is lowered when the cutting temperature is high. This phenomenon is avoided by the fact that CVD diamond does not contain a binder. In addition, CVD diamond has good lubricity and thermal conductivity, giving it a key advantage in high speed and dry cutting.
The last advantage of CVD diamond is that it maintains high hardness and wear resistance even at high cutting temperatures. Nagy, Norton's application technology manager, said: "Because there is no soft cobalt wrapped in diamond, the hardness of the blade is uniform."
Bright prospects GE's Super Abrasives and Norton DiamondFirm believe that many production sites do not take full advantage of diamonds. The reason is that the speed and torque of many machine tools are not enough to ensure the high efficiency of the tool.
In addition to the mechanical problems, there is a difficult problem to convince the people in the production plant not to focus on the initial price of diamond (PCD or CVD diamond), but to see the cost savings and performance improvements it brings. benefit. You can increase the throughput by allowing diamonds to run at higher speeds than conventional tools (depending on machine performance). At the same time, the number of tool changes is also small. Assuming that diamonds are 50 to 100 times longer than cemented carbides, you don't have to shut down often.
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