Developed and owned by Precorp Inc. of Utah, USA, the high-voltage monolithic sintered PCD bit (PCD-veineddrill) with technology patent name DiaEdge has been applied to metal cutting since the late 1980s, but the drill has not been used for many years. Can establish a high degree of credibility in people's minds. Today, this type of sintered VCD drill bit, which is grooved along the length of the drill bit groove and obtained by high-temperature and high-pressure sintering of polycrystalline diamond (PCD) powder in the groove, has received a lot of attention. Its application range has also been widely expanded. . High-pressure monolithic sintered PCD drills were initially used sporadically in the processing of aerospace parts and electronic devices. Today, it has become a common tool for machining difficult-to-machine materials in the aerospace, electronics, automotive, and medical device industries, and its application range continues to expand.
Diamond has the highest hardness and the smallest coefficient of friction and is an ideal material for preparing cutting tools. The main process steps of Precorp's manufacturing of DiaEdge polycrystalline diamond drills are: 1 Preparation of solid carbide drill tip blanks; 2 Narrow grooves on drill blanks; 3 Incorporation of PCD diamond powder and binder into the trough; 4 The drill blank is placed in a special sintering press and sintered at 1480°C and 61320kg/cm2 under high temperature and high pressure. 5 The diamond tip blank embedded with a PCD land is obtained; 6 The drill bit blank is welded to the solid carbide drill. On the rod blank; 7 Grind the required geometry of the drill bit. Using this process, an integrally sintered PCD drill having a complex drill tip shape can be prepared, and the drill diameter can be as small as φ0.4 mm. This drill is very suitable for high-speed, high-efficiency drilling.
The length of the drill tip and drill pipe weld joint from the cutting edge depends on the size of the drill bit diameter. The distance should be such that the weld joint will not be affected by the heating of the cutting zone during processing to ensure the integrity of the joint and the blade body. Because the integrity of the welded joint and the body is the weak link of the diamond tool, it is necessary to carefully study the characteristics of the high-pressure integrated sintered PCD bit different from the conventional welded type PCD bit.
The conventional PCD drill bit is usually prepared by machining a groove at the drill tip, cutting the PCD film deposited on the cemented carbide substrate by wire cutting, and then welding it in the drill tip groove. In the late 1980s, only a few manufacturers in the world (including Precorp) were able to successfully prepare PCD drills. In the early 1990s, welded PCD drills were used to drill locator holes in pistons of automotive engines. The pistons were hypereutectic aluminum alloy castings (silicon content 12% or more) and must be machined with PCD bits to achieve the desired tooling. Life, the drill sharpening once usually can process 3500 pairs of holes (in fact, it may reach 10,000 processing holes). However, welding PCD drills require longer machining times and higher processing costs per piece. In addition, the cutting edge of the drill bit often suffers from welding failure under high temperature, resulting in breakage of the entire drill bit. Using an integrally sintered PCD drill can better solve the above problems.
Precorp's DiaEdge integrated sintered PCD drills were originally designed for the electronics and aerospace industries. With further processing trials, the field of application of this technology is gradually expanding. At present, the drill can be used to process green hard alloys, aluminum matrix composites, reinforced composite ceramics, and various grades of aluminum materials. The processing objects include automotive engine housings, transmission boxes, wing beams of new jet fighters, and so on. The fighter wing spar is made of composite resin material with excellent toughness. The drill processing volume is very large. For example, each surface of the wing of the F-22 jet fighter needs to drill 3,500 holes, and the upper and lower surfaces of each wing need to be drilled. Cut 14,000 holes. In the past, it took 16 hours to machine a 20m spar with a carbide drill, which is now 4.5 hours using an integrally sintered PCD drill. Reducing the processing cost and processing time per hole is a major factor affecting the total cost of processing, and is also an advantage of using an integrally sintered PCD drill bit. At present, the United States aviation industry has planned to use the whole sintered PCD drill bit for the production and processing of B-2, A-6, 777 and other models.
Since the price of a diamond drill is many times that of a conventional hard alloy drill, in order to reduce the processing cost per hole, the processing cost must be balanced by extending the tool life and shortening the machining time of the machine tool. The same principles apply to the overall sintered PCD drill compared to conventional welded PCD drills. If the use of integrated sintered PCD drill bit can significantly reduce the possibility of tool failure, this drill bit can significantly improve the drilling process of difficult-to-machine materials. Since the development of processing technology is ultimately driven by user demand, it is difficult to determine whether it is best to use an integrally sintered PCD drill or a conventional welded PCD drill. Therefore, it is very important to carefully study the material to be processed and the process integrity when selecting the tool. The close cooperation between the machining department and the tool manufacturer is the best way to meet the needs of users. For example, the Honda Transmission manufacturing facility in Ohio, USA has successfully applied Precorp's integrated sintered PCD drill/reamer (trade name OneShot) to the processing of automotive actuators, thereby reducing the original three-step process to one step Increased productivity. According to the latest statistics, Honda Transmission Factory has used this tool to process more than 300,000 holes, reduced production costs, improved product quality, and shortened the production cycle.
The traditional application field of the integrated sintered PCD drill manufactured by Precorp is mainly aerospace manufacturing for processing carbon fiber reinforced plastic workpieces. When machining this material, the sharpness of the cutting edge is critical. For example, if the drill edge is dull, carbon fibers in the material may be torn during processing, thereby destroying the integrity of the orifice. The use of sharp-edged sintered PCD drill bits reduces the impact of the drill bit, and the cutting edge can trim the carbon fiber at the orifice. Through a large number of actual processing, the recommended cutting speed and feed rate for the carbon fiber reinforced plastic processed by the integrated sintered PCD bit can be obtained. The small feed rate (about 0.025-0.05mm/r) and excessive cutting speed (100-200m/min or more) used to prevent delamination of the processed material will generate large cutting heat, which will cause the material The resin melts and requires coolant for processing. Dry drilling with advanced chip vacuum suction system can also receive good processing results. The processing practice shows that the number of drilled holes in the overall sintered PCD drill is 3 times the number of standard (118°) drilled PCD drills, 6 times the number of drilled PCD insert bits, and 100 times the number of drilled carbide drill bits. .
With the continuous development of high-speed machining technology, sintered PCD drill bits and other rotating tools will be more widely used. This is because the high-speed machining of machine tool spindle speeds exceeding 10000 r/min has little effect on the diamond tools used on high-rigidity machine tools. . Today, sintered PCD drill bits have been used in the automotive industry to process carbon fiber-reinforced plastic parts. For example, a GM Powertrain plant in Michigan, USA, uses an integrally sintered PCD drill called “freedrill†to machine a car's transmission case. Transverse hole. The original use of carbide drill bit processing, the drill easily dull, and cause drilling burrs, so need to change the drill every day. After switching to the integrated sintered PCD bit, although the cost of the bit itself is increased by 5 times than before, the tool processing life is greatly extended, and only one blade per year is needed. The Robert E. Morris Turbine Group, which manufactures carbon-carbon material aircraft brakes, has also recently successfully completed a process test for the use of integrally sintered PCD drill bits for machining brake materials. In fact, drilling of metal-based composite brake materials is becoming a major application area for sintered PCD drill bits in the automotive industry. Alcan, a major manufacturer of metal matrix composites (MMCs), has included Percorp's integrated sintered PCD drills as a process guide for processing MMC materials. Although the addition of silicon carbide and alumina particles in the MMC material can significantly improve the mechanical properties of the composite material, the hard phases in the material also aggravate tool wear during processing. So far, diamond tools are still the most effective tools for machining MMC materials. The unique structure of the sintered PCD drills makes them have excellent wear resistance, and can obtain high processing dimensional accuracy and surface quality, in some cases completely The subsequent reaming step can be omitted.
It can be foreseen that the overall sintered PCD tool will be used more and more widely in machining workshops in the future.
Diamond has the highest hardness and the smallest coefficient of friction and is an ideal material for preparing cutting tools. The main process steps of Precorp's manufacturing of DiaEdge polycrystalline diamond drills are: 1 Preparation of solid carbide drill tip blanks; 2 Narrow grooves on drill blanks; 3 Incorporation of PCD diamond powder and binder into the trough; 4 The drill blank is placed in a special sintering press and sintered at 1480°C and 61320kg/cm2 under high temperature and high pressure. 5 The diamond tip blank embedded with a PCD land is obtained; 6 The drill bit blank is welded to the solid carbide drill. On the rod blank; 7 Grind the required geometry of the drill bit. Using this process, an integrally sintered PCD drill having a complex drill tip shape can be prepared, and the drill diameter can be as small as φ0.4 mm. This drill is very suitable for high-speed, high-efficiency drilling.
The length of the drill tip and drill pipe weld joint from the cutting edge depends on the size of the drill bit diameter. The distance should be such that the weld joint will not be affected by the heating of the cutting zone during processing to ensure the integrity of the joint and the blade body. Because the integrity of the welded joint and the body is the weak link of the diamond tool, it is necessary to carefully study the characteristics of the high-pressure integrated sintered PCD bit different from the conventional welded type PCD bit.
The conventional PCD drill bit is usually prepared by machining a groove at the drill tip, cutting the PCD film deposited on the cemented carbide substrate by wire cutting, and then welding it in the drill tip groove. In the late 1980s, only a few manufacturers in the world (including Precorp) were able to successfully prepare PCD drills. In the early 1990s, welded PCD drills were used to drill locator holes in pistons of automotive engines. The pistons were hypereutectic aluminum alloy castings (silicon content 12% or more) and must be machined with PCD bits to achieve the desired tooling. Life, the drill sharpening once usually can process 3500 pairs of holes (in fact, it may reach 10,000 processing holes). However, welding PCD drills require longer machining times and higher processing costs per piece. In addition, the cutting edge of the drill bit often suffers from welding failure under high temperature, resulting in breakage of the entire drill bit. Using an integrally sintered PCD drill can better solve the above problems.
Precorp's DiaEdge integrated sintered PCD drills were originally designed for the electronics and aerospace industries. With further processing trials, the field of application of this technology is gradually expanding. At present, the drill can be used to process green hard alloys, aluminum matrix composites, reinforced composite ceramics, and various grades of aluminum materials. The processing objects include automotive engine housings, transmission boxes, wing beams of new jet fighters, and so on. The fighter wing spar is made of composite resin material with excellent toughness. The drill processing volume is very large. For example, each surface of the wing of the F-22 jet fighter needs to drill 3,500 holes, and the upper and lower surfaces of each wing need to be drilled. Cut 14,000 holes. In the past, it took 16 hours to machine a 20m spar with a carbide drill, which is now 4.5 hours using an integrally sintered PCD drill. Reducing the processing cost and processing time per hole is a major factor affecting the total cost of processing, and is also an advantage of using an integrally sintered PCD drill bit. At present, the United States aviation industry has planned to use the whole sintered PCD drill bit for the production and processing of B-2, A-6, 777 and other models.
Since the price of a diamond drill is many times that of a conventional hard alloy drill, in order to reduce the processing cost per hole, the processing cost must be balanced by extending the tool life and shortening the machining time of the machine tool. The same principles apply to the overall sintered PCD drill compared to conventional welded PCD drills. If the use of integrated sintered PCD drill bit can significantly reduce the possibility of tool failure, this drill bit can significantly improve the drilling process of difficult-to-machine materials. Since the development of processing technology is ultimately driven by user demand, it is difficult to determine whether it is best to use an integrally sintered PCD drill or a conventional welded PCD drill. Therefore, it is very important to carefully study the material to be processed and the process integrity when selecting the tool. The close cooperation between the machining department and the tool manufacturer is the best way to meet the needs of users. For example, the Honda Transmission manufacturing facility in Ohio, USA has successfully applied Precorp's integrated sintered PCD drill/reamer (trade name OneShot) to the processing of automotive actuators, thereby reducing the original three-step process to one step Increased productivity. According to the latest statistics, Honda Transmission Factory has used this tool to process more than 300,000 holes, reduced production costs, improved product quality, and shortened the production cycle.
The traditional application field of the integrated sintered PCD drill manufactured by Precorp is mainly aerospace manufacturing for processing carbon fiber reinforced plastic workpieces. When machining this material, the sharpness of the cutting edge is critical. For example, if the drill edge is dull, carbon fibers in the material may be torn during processing, thereby destroying the integrity of the orifice. The use of sharp-edged sintered PCD drill bits reduces the impact of the drill bit, and the cutting edge can trim the carbon fiber at the orifice. Through a large number of actual processing, the recommended cutting speed and feed rate for the carbon fiber reinforced plastic processed by the integrated sintered PCD bit can be obtained. The small feed rate (about 0.025-0.05mm/r) and excessive cutting speed (100-200m/min or more) used to prevent delamination of the processed material will generate large cutting heat, which will cause the material The resin melts and requires coolant for processing. Dry drilling with advanced chip vacuum suction system can also receive good processing results. The processing practice shows that the number of drilled holes in the overall sintered PCD drill is 3 times the number of standard (118°) drilled PCD drills, 6 times the number of drilled PCD insert bits, and 100 times the number of drilled carbide drill bits. .
With the continuous development of high-speed machining technology, sintered PCD drill bits and other rotating tools will be more widely used. This is because the high-speed machining of machine tool spindle speeds exceeding 10000 r/min has little effect on the diamond tools used on high-rigidity machine tools. . Today, sintered PCD drill bits have been used in the automotive industry to process carbon fiber-reinforced plastic parts. For example, a GM Powertrain plant in Michigan, USA, uses an integrally sintered PCD drill called “freedrill†to machine a car's transmission case. Transverse hole. The original use of carbide drill bit processing, the drill easily dull, and cause drilling burrs, so need to change the drill every day. After switching to the integrated sintered PCD bit, although the cost of the bit itself is increased by 5 times than before, the tool processing life is greatly extended, and only one blade per year is needed. The Robert E. Morris Turbine Group, which manufactures carbon-carbon material aircraft brakes, has also recently successfully completed a process test for the use of integrally sintered PCD drill bits for machining brake materials. In fact, drilling of metal-based composite brake materials is becoming a major application area for sintered PCD drill bits in the automotive industry. Alcan, a major manufacturer of metal matrix composites (MMCs), has included Percorp's integrated sintered PCD drills as a process guide for processing MMC materials. Although the addition of silicon carbide and alumina particles in the MMC material can significantly improve the mechanical properties of the composite material, the hard phases in the material also aggravate tool wear during processing. So far, diamond tools are still the most effective tools for machining MMC materials. The unique structure of the sintered PCD drills makes them have excellent wear resistance, and can obtain high processing dimensional accuracy and surface quality, in some cases completely The subsequent reaming step can be omitted.
It can be foreseen that the overall sintered PCD tool will be used more and more widely in machining workshops in the future.