Pressure sintering using conventional methods is difficult to achieve

Instruments of diamond powder, diamond powder products are mainly stage sintering furnace by sintering compacts, sintered diamond tools and general process, the sintering temperature is influenced by changes in  Diamond blade graphitization temperature limit, the binder of the diamond easily not strong bonding between the diamond or cause burning, and for shaped diamond powder products (such as sawtooth workpiece, the workpiece surface, etc.), the use of conventional pressure sintering method is difficult to achieve, the current general shaped workpieces by means of  synthetic diamond powder obtained benefit from this method, using a laser to make powder compacts fast heating and subsequently cooling rapidly the characteristics of the entire sintering process time can be greatly reduced at higher  synthetic diamond to avoid excessive burning of diamond, diamond tools combined conventional sintering techniques proposed new diamond powder tool manufacturing method --- diamond powder compacts laser sintering, can reduce diamond burning, improve the sintered body of the diamond substrate holding force, but also for shaped sintered .

Ti-containing powder compacts is more susceptible to oxidation

Process Study showed that: ① sintered in a non-protective atmosphere containing Ti powder compacts is more susceptible to oxidation, powder for powder wettability is poor, wear resistance is lower. ② amount of  Diamond blade  increases (amount of the scanning speed decreases), is conducive to the densification of sintered parts and strong carbide forming elements on the diamond powder infiltration, but if the energy of the laser input line exceeds a certain threshold will result in  polycrystalline diamond . When the spot diameter is 8.5mm, the laser power of 550W, scanning speed 1100mm/min under sintering conditions, powder sintering tool has the best performance. ③ The same process parameters, since the laser  grinding wheel compacts composition non-uniformity, surface state powder and metal binding properties and differences. For the laser sintering process in a variety of different phenomena, the sintering mechanism were studied intensively

Developed a new purification method for ultra-fine diamond powder

Also discussed in the purification process of the ultrafine diamond powder grading, purification and grading will combine. The reagent-treated fine powder was washed by centrifugation, adding a certain proportion of the surface active agent, and observed under the microscope. By a large number of experiments, we developed a new  abrasive wheels  for fine diamond powder: the dedicated reagent strong ultrasonic dispersion, prepared open diamond agglomerates formed during impurities, which is due to high  abrasive grinding pressure such that the resultant diamond single crystal particles and the reaction raw materials, additives,  Polycrystalline diamond other closely bonded together and form, thus increasing the contact area of ​​the reagent, the effect to improve the decomposition of impurities, finally obtained purified to more than 99.95% ultra-fine diamond powder.

Trends whether natural or synthetic diamond powder are today's international one kind of super fine abrasive

Diamond powder is a super fine abrasive, in science and industrial applications more widely. As high-tech development, the production of diamond powder some noteworthy trends. Keywords diamond powder, uses, trends whether natural or synthetic diamond powder are today's international one kind of super fine abrasive. With the development of high  cutting tools , it is in the industrial sector more widely. In the mid-1960s, the Soviet Union used in industry, 70% of the natural diamond is made ​​of  abrasive wheels used for crushing, grinding paste diamond and diamond tools. Since artificial stone into industrial-scale production later this part of the natural  abrasive grinding has almost all been replaced by synthetic diamond. According to statistics, by the end of the 1960s, the Soviet Union manufactured diamond tools, 95% were using synthetic diamond, only 5% is made of natural diamond. In the 1990s, the former Soviet Union's annual output of about synthetic diamond reach 100 million carats.

Fixed to the spindle head of the tool electrode and the workpiece fixed on the table

Fixed to the spindle head of the tool electrode and the workpiece fixed on the table, respectively, with two high-frequency pulse power supply connected to the output, the first drive shaft of the tool electrode of hollow thin-walled tubular high-speed rotation, while the high-pressure gas through the intermediate electrode the media will discharge machining debris produced during machining away. This  abrasive wheels  overcomes the kerosene and other liquid media will produce harmful gases caused by  Abrasive grinding wheel  pollution problems; tool electrode liquid medium without limitation, in any direction, machining scope. Green is an efficient processing methods. The discharge process mainly through discharge between the workpiece and the tool electrode generates heat, melt the workpiece material, gasification and thrown, and thus the heat flow is the main material removal. Discharge machining process of the discharge surface of the workpiece size and depth of pits are made of a single energy pulse discharge decision.

Resulting composite sheet deformation of the sequence after processing has brought great difficulties

A large area of ​​polycrystalline diamond with high hardness, high wear resistance, high utilization of materials can, in the automotive, aerospace, wood processing, oil industry, geological drilling, electronic industry and other fields are widely used, but it is also a great difficulty of processing . The most effective method is to discharge  abrasive wheels , the material removal rate was 12.56 mm3/min. Since the discharge channel during processing with high temperature and pressure, after processing of polycrystalline diamond surface residual stress inevitably, resulting deformation of the composite sheet, after the sequence of machining led to great difficulties, thus seriously affecting the composite sheet the processing quality. Therefore, studying a large area polycrystalline diamond compact EDM grinding process  polycrystalline diamond  field and residual stress distribution, to reveal the EDM grinding mechanism and to improve the quality of products is important. At present, many domestic and foreign scholars on the single pulse EDM  Diamond blade  and stress field in a lot of research, but the actual processing is continuous pulse, so the simulation results with the actual situation is still some distance away, this paper studies EDM mechanism, based on the initial spark for polycrystalline diamond compact continuous pulse discharge grinding process workpiece surface temperature field, stress field distribution and the deformation of the workpiece material were simulated and analyzed.

The results show that the gas spark discharge is started by the breakdown

Gas medium is a green discharge machining process, so that the processing method by domestic and foreign scholars in the field of EDM research attention, EDM research in the field is one of the hotspots. Spark discharge mechanism for gas conducted in-depth research. The results show that the gas breakdown spark discharge is started, and gradually developed into the streamer breakdown formed; gas discharge  Abrasive grinding  than the liquid discharge channel expansion fast; gas discharge process galvanic corrosion products mainly thrown by thermal explosive, high-pressure air blowing force, the magnetic hydrodynamic result of joint action, and for brittle materials, thermal stress erosion plays a dominant role. Single pulse for a spark discharge gas experiment results show that the positive polarity  cubic boron nitride  the workpiece on a single pulse discharge pit ratio to be negative when processing large, and the positive polarity monopulse processing anode is higher than the cathode erosion amount of erosion; compressed air discharge medium single pulse discharge pits  cutting tools  air of the single pulse discharge pits should be large, and the shape of the discharge pits due to airflow blowing action extends along a certain direction; gas both the single pulse discharge pit with the increase of discharge energy.