Self-oscillating flow field inside the nozzle chamber variation, internal and external flow field dynamic pressure variation

Abrasive jet formation mechanism of the pulse, the pulse characteristics and pulsed abrasive water jet abrasive jet perforating stimulation mechanism and other issues have been studied, and in the Sichuan Basin, a gas well site experiments. The main  polycrystalline diamond : first using a large eddy simulation, through in-depth analysis of the self-oscillating flow field inside the nozzle chamber variation, internal and  synthetic diamond  field dynamic pressure variation, variation of the velocity vector, turbulence intensity distribution, revealing the self-oscillating  abrasive wheels  jet generation mechanism; combined oscillation, bubble collapse on the abrasive jet impact and solid abrasive water jet in the pulse distribution of abrasive water jet pulses revealed the formation mechanism.

Using perforating fracturing methods to transform strata, increased gas production

Low-permeability gas widely distributed in China, large reserves, proven gas reservoirs representing more than 80%. However, due to porosity, permeability and pressure is low,  polycrystalline diamond low productivity and economic inefficiency. In order to increase natural gas production, to solve the "gas shortage" problem, now mostly using perforating fracturing methods to transform formation, increased  Diamond blade . However, the conventional way of perforation perforation shallow depth, hole diameter is small, the construction for a long time, can lead to gas  Synthetic diamond , resulting in low permeability gas reservoirs, yield poor. For these reasons, this paper proposes a pulsed abrasive water jet perforation penetration increased permeability gas reservoir to increase natural gas production of new ideas.

In submerged conditions before and after mixing abrasive jet impact angle, flow, pressure

Using FLUENT software, submerged abrasive jet multiphase flow simulation, calculation of different structural forms of the nozzle flow field inside and outside. Explored the submerged condition after mixing abrasive jet impact angle, flow, pressure, target distance, sand tube length, tube diameter mixed sand, abrasive concentration,  synthetic diamond  change on the nozzle flow field inside and outside the law, on the abrasive particles running track were predicted, while the flow field  polycrystalline diamond  and calculation results are analyzed. For premixed abrasive water jet, respectively, direct numerical simulation of 260,450,600 cone type nozzle and external flow field and grain motion characteristics, and submerged jet  abrasive grinding  under influence factors - target distance, angle of impact and confining pressure for the simulation analysis. The results showed that: there is a submerged abrasive jet jet core, is about (35) D, but then jet decay rapidly. Cylinder, cone, cone straight three typical straight-type nozzle nozzle cone best, and to 260 straight cone nozzle effect is better.

Water by adding abrasives (ie, abrasive water jet) is to improve the performance of an important way jet

For higher pressure jet working condition, basically limited to some of the research sector from abroad pressure generator and jet equipment research work. Attempts have been made in the high-pressure water jet technology, and continue beyond the new high record Generally said current level of technology enables people to use 200 ~ 400 MPa  synthetic diamond  while with further increase the pressure in the device and the device manufacturing, material, cost and other aspects of life will be limited, there is also the use of security .70 years, people began to note exhausted improve the work efficiency of the jet, focusing on research work  synthetic diamond powder  not too high but with a high-performance jet mechanism, for example, additives jet, 'pulse jet, resonance jet, jet and abrasive water jet cavitation in an attempt to lower operating pressure, achieve a higher economic  cutting tools , added to the water abrasive (ie, abrasive water jet) is to improve the performance of a jet important way. abrasive jet high pressure water jet and general different, it is a highly concentrated jet of energy, the working medium is water and a mixed solution of abrasive particles.

Explained rotating abrasive jet nozzle jet nozzle wear serious than ordinary phenomenon

Comparison of the rotating abrasive jet nozzle and the general stress abrasive jet nozzle, the results showed that: the former is much larger than the maximum stress in the latter, which could well explain the rotating  Polycrystalline diamond  nozzle jet nozzle wear serious than  abrasive grinding . Study of the various parameters of the law of the nozzle wear, these parameters were as follows: the abrasive characteristics (shape abrasive,  Diamond blade  size, grain hardness, abrasive concentration), nozzle material properties and surface quality (hardness nozzle, abrasive hardness H_α and nozzle material hardness H_m ratio nozzle processing quality), nozzle structural parameters (inlet contraction angle, nozzle diameter), the jet operating parameters.

Erosion in the nozzle inlet end face wear play a major role

From the nozzle wear mechanisms and effects of two parts for rotary drilling abrasive jet conducted exploratory research. Through  polycrystalline diamond  analysis, the rotating abrasive jet nozzle wear plays a decisive role in the abrasive wear and erosion. Where  cutting tools  is the main form of the nozzle inner wear, and erosion in the nozzle inlet end face wear plays a major role, and were the two wear mechanisms were discussed.  synthetic diamond  method analysis of the stress state in the nozzle. The results showed that: the maximum stress in the nozzle cone section at the beginning of the end of the straight section, the stress cone section is smaller and showed an increasing trend, the average stress is greater than the straight section cone section, in addition to the entrance face of stress as well.

Rotating water jet diffusion angle measured experimental analysis of all relevant parameters on the jet spread angle of the law

Combined rotary abrasive jet casing window casing window mechanism and a set of practical requirements designed impeller, nozzle suitable for indoor as well as experimental research tools, and its strength check. Checking results show that the designed tools to meet the requirements. By  abrasive wheels  jet diffusion angle measured  synthetic diamond  analysis of all relevant parameters on the jet spread angle is studied. The experimental results showed that: rotating water jet pump is larger in the diffusion angle does not vary with the pump pressure is changed, the proliferation of  cutting tools  with water jet nozzle diameter, the impeller blade outlet angle and the number increases. By rotating the casing window abrasive jet experimental analysis of all relevant parameters on the effect of regular windows and preferably out of the relevant parameters.

Small screw motor driven mechanical gimbal drive alloy drill fenestration

In a variety of technology to improve oil recovery, the radial horizontal well technology with its operating procedures are simple, the process cycle is short, less investment, etc. showed good technical and  abrasive grinding . Applications at home and abroad to open a small window radius horizontal well technology uses small screw driver alloy  synthetic diamond  driven mechanical drill fenestration, because underground space constraints, the level of domestic screw motor technology is difficult to meet the requirements. To this end we introduce rotating abrasive jet  cutting tools , and its realization casing window, expand the relevant theoretical analysis and experimental research tools designed to promote open small window radial level technology application in China.

Based abrasive water jet cutting efficiency and high rotating jet good scalability characteristics

The traditional radial drilling technology requires forging mill and a large diameter casing reaming, operating procedures and more difficult construction. Casing window radial horizontal well technology simply open the casing with a diameter of about 30 mm of the window, to the formation of radial drilling channels. At present, foreign multi-use mechanical window. Based abrasive water jet cutting efficiency and high rotating jet good scalability characteristics, the author proposes a  synthetic diamond  jet technology line window, and through numerical simulation and laboratory tests to analyze the combination of means for the further development and improvement of open  Polycrystalline diamond  technique provides a theoretical basis. Injury and damage criterion variable in metallic materials RVE, assuming a  Abrasive grinding  area A normal vector is n, the micro-cracks or micro-voids exist, resulting in an effective bearing area A Zhou ratio A small, that Zhou A = A-AD. AD is considering stress concentration defects and defect area after interaction. In the assumption of isotropy of the premise, the damage variable defined as a defect area and the total area ratio, i.e. D = ADA = A-Zhou AA. (2) when D = 0, the metal material is non-destructive condition; D = 1 , the metal material is completely broken;

Combination of different impeller nozzle to simulate structural characteristics and results rotating jets of various factors

The newly developed rotary abrasive jet casing window tool, using numerical simulation method, the tools to optimize the structure and size of the design . Rotate tool abrasive jet casing window is the core component of the jet nozzle and rotating impeller . From the nozzle and impeller geometry and basic characterization can be seen, leaf number, as well as export-oriented angle nozzle diameter and other parameters that affect the efficiency of rotating abrasive jet major factor . Numerical method, the combination of different impeller nozzle simulation results and the structural  Diamond blade  of rotating jets of various  synthetic diamond  jet spread angle of rotation rule ; through the individual abrasive particle erosion simulation casing , the casing draw stress , strain change process , abrasive particles displacement, velocity change process , as well as the depth of various factors on the impact of erosion pits law ; abrasive jet by  abrasive grinding  window full-size simulation tool , draw nozzle phase fluids inside and outside the field distribution of the casing and a rotating abrasive jet erosion damage process . Finally, the structural parameters of the impeller nozzle size optimization , preferably windows meet the requirements of the impeller and the nozzle , and the simulation and experimental results are compared to verify the accuracy of the simulation results .

Abrasive jet cutting subsea wellhead operating efficiency, to carry out the relevant theoretical and experimental

Demolition work in the offshore oil platform, the abandoned wellhead underwater cutting is one of the most important and most expensive one engineering work. Multilayer casing abrasive jet cutting technology has abandoned wellhead safety, environmental protection advantages. But conventional abrasive jet cutting tool cutting subsea wellhead, due to the ever-increasing standoff distance reduces the cutting efficiency. To improve the abrasive jet cutting subsea wellhead operating efficiency, to carry out the relevant theoretical and experimental studies. The first systematic study using  Diamond blade  of various parameters on the abrasive jet cutting efficiency. The results showed that: the depth of the abrasive jet cutting  cutting tools  pump pressure, nozzle diameter, the number of nozzles, cutting the time increases, as the target distance decreases; with the increase of the cutting speed of the cutting head casing depth first increases and then decreases, the optimal  grinding wheel l 7.895r/min; with the abrasive concentration increases, the cutting depth along first and then decreases, experimental optimum abrasive mass concentration value of 26.10%; abrasive abrasive jet cutting depth in descending order of iron ore, emery, garnet, quartz sand.

Abrasive water jet cutting metal materials physics

Abrasive jet cutting is not subject to the cutting position and the eccentric bushing restrictions, thus becoming obsolete wellhead and riser removal and effective means. Based on the theoretical analysis of cavity expansion abrasive jet cutting metal materials physical process, the establishment of a single abrasive particle  synthetic diamond powder  depth calculation model, obtained the higher jet pressure, the use of high density and with a sharp angular abrasive can significantly improve the cutting efficiency of the law, as the construction work is  synthetic diamond  category provides a theoretical basis. Were submerged jet under pressure, nozzle diameter, number of nozzles, cutting head speed, cutting duration, standoff distance, abrasive quality copies, abrasive type on cutting depth effect.

Mainstream mechanical cutting techniques in cutting

With the offshore oil and gas exploration and development progresses, a number of offshore platforms have completed their mission, platform removal has become a hot project. Platform is one of the key technologies demolition waste wellhead and riser Abrasive grinding of the current foreign mainstream mechanical cutting techniques in cutting, drilling tablets cable cut, shaped blasting abrasive jet cutting and cutting. As is by the multi-layer casing and  Diamond blade  cemented together and there may be eccentric, but need to cut at 5m below the seabed, drilling and mechanical cable cutter grain cutting method is difficult to meet the project needs, and shaped cutting due to blasting a greater damage to the environment, gradually limit the use of;

Mainstream mechanical cutting techniques in cutting, shaped cutting and blasting abrasive jet cutting

With the offshore oil and gas exploration and development progresses, a number of offshore platforms have completed their mission, platform removal has become a hot project. Platform is one of the key technologies demolition waste wellhead and riser  synthetic diamond  of the current foreign mainstream mechanical cutting techniques in cutting, drilling tablets cable cut, shaped blasting abrasive jet cutting and cutting. As is by the multi-layer casing and  Diamond blade  cemented together and there may be eccentric, but need to cut at 5m below the seabed, drilling and mechanical cable cutter grain cutting method is difficult to meet the project needs, and shaped cutting due to blasting a greater damage to the environment, gradually limit the use of;

Mainstream mechanical cutting techniques in cutting, shaped cutting and blasting abrasive jet cutting

With the offshore oil and gas exploration and development progresses, a number of offshore platforms have completed their mission, platform removal has become a hot project. Platform is one of the key technologies demolition waste wellhead and riser  synthetic diamond  of the current foreign mainstream mechanical cutting techniques in cutting, drilling tablets cable cut, shaped blasting abrasive jet cutting and cutting. As is  synthetic diamond powder  by the multi-layer casing and  Diamond blade  cemented together and there may be eccentric, but need to cut at 5m below the seabed, drilling and mechanical cable cutter grain cutting method is difficult to meet the project needs, and shaped cutting due to blasting a greater damage to the environment, gradually limit the use of;

Mainstream mechanical cutting techniques in cutting, shaped cutting and blasting abrasive jet cutting

With the offshore oil and gas exploration and development progresses, a number of offshore platforms have completed their mission, platform removal has become a hot project. Platform is one of the key technologies demolition waste wellhead and riser  synthetic diamond  of the current foreign mainstream mechanical cutting techniques in cutting, drilling tablets cable cut, shaped blasting abrasive jet cutting and cutting. As is  synthetic diamond powder  by the multi-layer casing and  Diamond blade  cemented together and there may be eccentric, but need to cut at 5m below the seabed, drilling and mechanical cable cutter grain cutting method is difficult to meet the project needs, and shaped cutting due to blasting a greater damage to the environment, gradually limit the use of;

Mainstream mechanical cutting techniques in cutting, drilling tablets cable cut, shaped cutting and blasting abrasive jet cutting

With the offshore oil and gas exploration and development progresses, a number of offshore platforms have completed their mission, platform removal has become a hot project. Platform is one of the key technologies demolition waste wellhead and riser  synthetic diamond  of the current foreign mainstream mechanical cutting techniques in cutting, drilling tablets cable cut, shaped blasting abrasive jet cutting and cutting. As is  synthetic diamond powder  by the multi-layer casing and wellhead riser cemented together and there may be eccentric, but need to cut at 5m below the seabed, drilling and mechanical cable cutter grain cutting method is difficult to meet the project needs, and shaped cutting due to blasting a greater damage to the environment, gradually limit the use of;

Abrasive jet cutting seam technology of theoretical research

Wells on the wall in the implementation of abrasive jet cutting seam injection technology to increase production, so that the economic benefits of oil has been great, so a lot of engineering and technical personnel in research on this technology. For abrasive jet cutting seam cutting tools , we must first study abrasive jet cutting cracks in the flow, and then study the material under the action of the jet damage, so as to determine the jet parameters, the development of  synthetic diamond provide a theoretical basis and foundation, so for abrasive water jet cutting theoretical study of sewing techniques, both academic value but also practical significance. When the jet of fluid flow in slotting the basic initial Abrasive grinding wheel segment dissipate when the sand pressure water ejected from the nozzle while moving from top to bottom on the wall casing to be cut, because the casing diameter slotted equipment space is filled with water jet fluid motion can be considered as free submerged jet. Because the nozzle orifice is circular cross section which is circular jet, the jet can be classified into several sections.

Application abrasive jet cutting technology in the underground rock formations on the wall surrounding the cutting

Abrasive jet slotting processing technology is the application of near-wellbore abrasive jet cutting technology in the underground rock formations on the wall surrounding the well cut with deep seam parallel to the axis, so that the well-storey week to  polycrystalline diamond , relieve compaction effect, the near-wellbore to restore the original permeability formations. Meanwhile, it penetrates deep seam produced by the well construction  abrasive wheels  workover wells near wellbore blockage, a new clean oil flow channel, thereby improving near-wellbore permeability  synthetic diamond  pressure, increased oil production and oil recovery . After several ground simulation test and field applications, and achieved good results, after the construction of a general increase oil production wells more than 1 times, can be maintained for 2 years or more.

To overcome the resistance caused by compaction effect

Oil (water) wells drilled, causing stress redistribution, borehole stratigraphy affected stress increased compaction effects occur, rock fissures occur in varying degrees within the pores closed, so that the formation of porous and fractured connecting  synthetic diamond powder  becomes too narrow, permeability reduction, fluid flow resistance increases, flow rate, flow rate decreases, oil production wells, water injection wells decreased. Especially late in oilfield development,  cubic boron nitride  drops, not enough to overcome the resistance caused by compaction effects, crude oil can not flow into the wellbore by a borehole formed within the dead wells, thus eliminating the oil wells near wellbore compaction effect, restoring the original formation some penetration as well stimulation, well stimulation, enhanced oil recovery essential way.

Wells abrasive jet cutting seam, sew the body fluid in the flow

Abrasive jet cutting seam technology is developed in an eighty year-end for releasing pollution and expand the near-wellbore permeability reservoir permeability of the new technology , with a penetration depth , no secondary pollution, the discharge area, the effect is significant construction and so on. But there are still many problems with the air compared to the free water jet , underwater jet  synthetic diamond  is also less . Especially for submerged conditions, high-speed non-free two -phase jet theory needs further study. The abrasive jet wells slotted body fluid flow at the seam , the movement of the solid particles ,  synthetic diamond powder  changes with time , the second return and the jet of fluid as the direction along the kerf attenuation rate few studies . To solve the above problems , this paper uses a theoretical and numerical investigation of the combination of research methods. The use of two -phase jet theory and   Diamond blade fluid dynamics and other basic knowledge , analysis wells abrasive jet slotting two-phase fluid motion mechanism . Gambit pre-processing software application , based on test results to establish the ground and underground seam 2D and 3D model of the body . Based on FLUENT software carried out on the two-dimensional numerical simulation of abrasive jet slotting process provides a theoretical basis and experimental evidence .

Slotted on casing strength analysis demonstrated slotted the casing does not have a big impact

Slotted casing strength through the impact on the analysis demonstrated slotted the casing does not have a big impact. Based on the above findings establish the mathematical model,  synthetic diamond powder  element analysis software ANSYS slotted wells around the well before and after the stress changes the numerical simulation results slotted rock  polycrystalline diamond  the well and spread the scope and impact analysis. Finally, the derived yield well before slotting the mathematical expression of the slotted slotted front and rear output compare output notes further explain and demonstrate the well stimulation mechanism and slotted slotted on yield changes.

Research abrasive jet cutting seam technology on the permeability change impact surrounding wells

Abrasive jet slotting well stimulation technique is the use of two-phase jet abrasive mechanism developed for improved oil recovery in an oil field technology. This article from the seepage - stress coupling based theory, a more comprehensive study on the abrasive jet cutting seam technology surrounding wells permeability  cutting tools  analysis slotted the impact on oil production situation. Application of rock, the effective stress and pore pressure, confining pressure and rock properties  Abrasive grinding  slotted through the rock around the well after the stress and permeability variation  synthetic diamond  and analysis, interpretation of the abrasive jet cutting seam technology to increase production wells the basic principle is the rock around the well after slotting the effective stress reduction and increased permeability of the results;

Abrasive jet with a small amount of abrasive particles formed from a mixture consisting of water jet

Abrasive jet slotting mechanism and mechanical model to study in order to establish oil ( water ) wells abrasive jet slotting theory, as the technology continues to improve and the process parameters to provide theoretical support . Slotted underground rock formations require two different types of metals and materials to be cut , so this study for universal abrasive jet cutting is also instructive significance and reference value. Abrasive jet with a small amount of abrasive  synthetic diamond  from a mixture consisting of water jet , according to the abrasive particle size , and the mass and volume of low concentration, uniform distribution , water flow rate is high, the abrasive particles can be characterized flows together with the water can be regarded as sparse balance solid-liquid two-phase flow .  cutting tools  a continuous medium , in the establishment of a solid-liquid two-phase flow on the basis of the basic differential equations , obtained with the solid-liquid two-phase equivalent single -phase fluid of the basic equations. Which can be applied to single-phase fluid mechanics and  abrasive grinding  fluid flow method problem . This paper uses polar coordinates , time-average method to create turbulence equations . By order of comparative law , the equation reduces to the corresponding turbulent boundary layer equations , namely freedom of circular cross-section turbulence abrasive jet differential equations .

Yearly amount of blade. Processing machinery blade main targets are non-metallic materials, thin blade slender

Mechanical blade is wood, paper, printing, leather and plywood industries processing raw materials and products necessary for the cutting tool, insert specifications varieties , heat treatment is difficult. With the rapid development of these industries , the amount of blade yearly . Processing machinery blade main targets are non-metallic materials , thin bladed slender . As the processing  synthetic diamond  requirement blade both have high hardness , toughness , wear resistance and a certain hot hardness , but also have a high resistance to fatigue cracking and spalling resistance carbide capacity, particularly Woodworking Sliced knives and peeling knives, using higher performance requirements .  abrasive wheels , dependent on imports for a long time , in recent years a breakthrough has not only domestically, but also for export. Application of heat treatment following introduction Jialong Gong Division new blade situation wrong, please correct me. Mechanical cutting blade. Mechanical blade manufacturing processes present, mechanical blade timber there are two situations : First, the overall alloy steel or high speed steel ; Second blade alloy steel or high speed steel blade back ( also known as the cutter body ) of carbon steel. The latter methods are forming and high temperature brazing nip splice categories.

Amorphous silicon thin film will not be light-induced attenuation effect (SW effect), it is considered highly efficient

Not only polycrystalline silicon thin film made ​​of silicon material having a bulk high mobility and high stability characteristics, and will not be an amorphous silicon thin film light-induced attenuation effect (SW effect), it is considered a high efficiency, low cost solar cell is ideal materials. Preparation of polycrystalline  synthetic diamond powder  mainly solid phase crystallization (SPC), excimer laser crystallization (ELA), metal-induced crystallization (MIC) and chemical vapor deposition (CVD) 3 ways. Of which the first two processes more complex, polycrystalline  synthetic diamond  prepared by metal induced the research team also made some more ideal research, Xia Donglin and other aluminum-induced electric field assisted prepared a  Diamond blade  silicon thin film. However, the polysilicon thin film metal induced high levels of metal impurities can not be directly used in the production of solar cells absorbent layer. CVD method, a hot filament chemical vapor deposition (HWCVD) has a low-temperature, low-cost, fast growth characteristics, and there is no plasma bombardment, little damage to the film.

Compared to the conventional amorphous silicon thin film, polycrystalline silicon film has a higher electron mobility and better optical stability

With the development of flat panel display technology and human importance of solar energy utilization , polycrystalline thin films attracted more and more attention. Compared with the conventional amorphous silicon thin film , polycrystalline silicon film has a higher electron mobility and better optical stability of the thin film transistor in flat panel displays as a channel layer and the silicon  synthetic diamond  cells have shown the use of absorbent layer more superior and stable performance. At present , the industrial preparation of polycrystalline silicon thin film deposition techniques which , mainly in chemical vapor deposition (CVD) based hot  Diamond blade  vapor deposition (HWCVD) , and plasma-enhanced chemical vapor deposition (PECVD) technique based. Chemical vapor  abrasive wheels  using a silane which is usually used as a reaction gas ; as an explosive dangerous toxic gas , the use of the silane in the industry need to be supplemented harsh security system and recycling system, resulting in high cost of polysilicon production high. Magnetron sputtering is a simple structure , low cost, a vacuum deposition technique . Since no silane , either production or cost control, safety , than the chemical vapor deposition by magnetron sputtering has a greater advantage .

Active matrix liquid crystal display is a relatively novel liquid crystal display technology

Active matrix liquid crystal display is a relatively novel liquid crystal display technology, in which each pixel switching by deposition on a large area glass substrate constituting the liquid crystal cells on the surface of a thin film electronic  abrasive wheels . Currently, it is the only - one kind has proved in color, grayscale and image quality can be comparable with the CRT LCD technology. Polysilicon thin film silicon materials have both high mobility and a large area amorphous silicon,  abrasive grinding  of the characteristics, and the active matrix liquid crystal display as the most ideal material thin film electronic device. Preparation of polycrystalline silicon thin film in many ways, including through the group phase crystallization of  Abrasive grinding wheel  thin-film method available polysilicon thin film with excellent performance, but due to the crystallization temperature> 600 "C; must use expensive quartz glass as the substrate; while crystallization time also up to 40h or so, which greatly hindered practical devices and industrialization. summarizes the formation of amorphous silicon and metal eutectic temperature and found that if amorphous metal contact, which will be far lower than the crystallization temperature crystallization temperature of the pure amorphous silicon.

Preparation Research progress in recent years and an outlook on future trends and prospects

In recent years, the polysilicon film is widely used in thin-film transistors (TFTs) and thin-film solar cells and other electronic devices by people's attention. In the polycrystalline silicon thin film in the various preparation techniques, hot filament chemical vapor deposition (HWCVD) its low deposition temperatures, high deposition rate and low cost which are widely used. First, an overview of hot  polycrystalline diamond  vapor deposition (HWCVD) polycrystalline silicon thin film preparation process of development, highlighting the preparation of this research progress in recent years and an outlook on future trends and prospects. On this basis, the paper in the preparation of high-quality  cubic boron nitride  silicon thin film has done some exploratory work: at a closer distance hot wire and the substrate (5mm ~ 10mm) under the (100) silicon wafers and ordinary glass slide high-quality polycrystalline silicon thin film  cutting tools  studied various process parameters on the crystal orientation of the film, the grain size and morphology were investigated. Study found that: hot wire and the substrate close spacing (5mm) of the polysilicon thin film crystal growth direction have a significant impact.

Contingency coefficient of polysilicon thin films

By LPCVD method under different conditions in polycrystalline thin films were prepared to study the process conditions on the polysilicon nano-thin film resistors, strain coefficients and their temperature coefficient, select the optimal  abrasive wheels . In this case, the gauge factor of polysilicon thin films to 34, compared with the same doping concentration ordinary polycrystalline silicon thin film is 25% or more;  grinding wheel  coefficient temperature coefficient 1 × 10-3 / ℃ nearby small than ordinary polycrystalline silicon thin film nearly doubled; resistance temperature coefficient of less than 1 × 10-4 / ℃, than ordinary  polycrystalline diamond  silicon thin film nearly an order of magnitude smaller. The selection of optimum conditions for polycrystalline thin films of the pressure sensor applied research to provide the necessary design basis.

Polysilicon piezoresistive theory is late in the last century, many researchers have formed the basis of a large number of experiments

Existing theories polysilicon piezoresistive late in the last century a large number of researchers formed on an experimental basis, and in the ordinary polycrystalline  cubic boron nitride  (thickness generally between a few hundred nanometers to several microns) piezoresistive Experimental and applications has been verified. Existing theory, the larger  polycrystalline diamond  the polycrystalline silicon thin film strain factor (GF) greater; heavy doping cases higher doping of the polysilicon thin film GF smaller. In general, the thinner the film, the smaller the grain, in accordance with existing silicon piezoresistive theory close to or less than 100nm thickness polysilicon thin films GF should have a smaller value.

PSNF piezoresistive properties has not yet attracted domestic and foreign researchers' attention

Polysilicon thin film piezoresistive properties make it good in the MEMS piezoresistive sensors have been widely applied. The research results show that the polycrystalline  abrasive wheels  (PSNF) has a more superior piezoresistive characteristics, has broad application prospects. However, PSNF piezoresistive properties has not yet attracted domestic and  grinding wheel ' attention, basic research in this area nearly empty. In this paper, the use of low pressure chemical vapor deposition (LPCVD) were  cubic boron nitride  different structures polysilicon thin films, on the basis of the experimental PSNF piezoresistive characteristics of a systematic study, to establish a theoretical model of polysilicon piezoresistive characteristics for such functional nanomaterials application development foundation.

Polycrystalline silicon thin films with the ordinary compared with the more superior film piezoresistive characteristics

Polysilicon thin film piezoresistive properties make it good in piezoresistive sensors have been widely applied. Existing research results show that the polycrystalline silicon thin films as compared with the ordinary polycrystalline silicon thin film has a  grinding wheel  piezoresistive characteristics, so has broad application prospects. In this paper, thin films of polysilicon piezoresistive  abrasive grinding  were studied, including processing conditions on the piezoresistive properties of silicon and polycrystalline silicon thin films Young's Modulus. Piezoresistive characteristics on the basis of research on nano-film polycrystalline silicon pressure sensor applied research. In the process conditions on the piezoresistive characteristics of the study.

Three ultra-high speed grinding of advanced technology in an advanced processing technology

Ultra-high speed grinding technology has been hailed as the "modern grinding peak ," has been listed as the International Institute of Production Engineering Center for the 21st century development. Ultra- high-speed point grinding technology is another new ultra high speed grinding applications forms , is a flexible CNC machining technology , CBN super abrasive , ultra high speed grinding three  Abrasive grinding  in an advanced processing technology . Ultra- high-speed ceramic CBN wheel technology is  abrasive wheels  grinding one of the key points , vitrified CBN grinding wheel because of its excellent performance and production process of the green, environmental protection , energy saving, low power consumption is recognized as a high-speed, high efficiency, high fine, low cost, low  Diamond blade  , high-performance wheels, racing around the world in recent years, the development of hot spots. This article from the ultra high-speed point grinding mechanism analysis start point for ultra high speed CBN wheel grinding ceramic structural characteristics , in accordance with the grinding theory and synthetic material preparation
Principle , its components and their key technologies, manufacturing processes for a more systematic research , and research and development of ultra- high-speed point grinding wheel grinding performance conducted experiments . Concludes the paper , outlining the ultra-high speed grinding technology and its theoretical research areas of development history. Systematically discusses the ultra high-speed ceramic CBN grinding wheel superiority and development at home and abroad .

Rational use of wheel, the use of appropriate electrolyte, select the appropriate electrical parameters

Electrolytic grinding process, including the rational use of wheel, the use of appropriate electrolyte, select the appropriate electrical parameters, using the correct sharpening methods. Carbide (YG) verification test tools, test was designed to improve the electrolytic grinding tools (D7540) performed on. Grinding wheel  abrasive grinding  choice: current  Polycrystalline diamond  many types of electrolytic grinding wheel, we choose two. One is electrolytic copper-based sintered wheel, a sintered  Synthetic diamond  particle size of 60, 30% concentration. Another is an iron-based sintered electrolytic grinding, abrasive is sintered corundum, particle size of 60, 40% concentration. Using the results of two wheels can achieve electrolytic grinding tools, copper electrolytic grinding wheel, grinding of good quality, an anti-electrolysis life of about 60 to 100 vehicles grinding flank.

If it is a different wheel designs will not, or how it will affect the accuracy of trajectory knife

Wheels, also called wheel. Grinding machine designed to split from two wheels, respectively, the upper and lower knives mounted on a position. This paper first discusses the wheel  synthetic diamond  the exact trajectory, but do not explore what the second "wheel of the processing should be grinding wheel  and other similar problems, and the third study is whether what kind of knife grinding wheel designed to make access to accurate trajectory. In other words, if it is a different wheel designs will not, or how it will affect the accuracy of trajectory knife. So,  synthetic diamond powder  side to split into knife knives centered on top of the wheel and under the knife under the wheel design is less known. In the tanning industry, from wet blue leather split between the world of new technology has been widely adopted because of the fresh human attention, researchers shortage. But most are "Because domestic aircraft do not know much, especially its structure described below" or "its merits numerous reports have been made" and so can not be obtained in a village a good article, does give future generations to enlightenment and thematic studies on the structure and properties of a split might affect rare.

By chamfering the edges of the cut wafers processed through the formation of an arc-shaped grinding wheel

Chamfering in silicon wafer processing plays an important role , it is a semiconductor material processing before the procedure , the main purpose is to improve the wafer edge quality , it will cut through the chamfered edge of the wafer after  synthetic diamond  to form a circular shape. Wafer chamfering machine for its high technical content , a huge market , with good development prospects. However, due to the machine control system complexity , action and more, data volume, high precision requirements of each action are independent, but the timing and inter-related , DMC motion control card in the software and hardware aspects have a strong feature,  grinding wheel  design, using this card , combined with the VB development environment to achieve a wafer chamfering machine control requirements , and have achieved good results. Chamfering machine motion control card system and implementation of this device in the development process , using a digital motion controller series of two independent board controller, motion control card features a motion control card intelligent motion control card , the internal 32-bit high-speed MCU ( micro-program controller unit ) can be controlled axes , while providing the servo and stepper motor interface, the user can be used in any combination , to achieve optimum control system configuration.

The current theory is the main factor to slip line because there is stress on the substrate sheet and the substrate crystal growth defects

The current theory is the main factor to slip line because there is stress on the substrate sheet and the substrate crystal growth defects. Classified according to the cause of stress for the mechanical and thermal stresses, and the stress on the substrate sheet is  synthetic diamond  in the ingot diameter roll mill and the wafer chamfering step. Therefore, to reduce the stresses generated during chamfering and how to Abrasive grinding wheel of stress on the epitaxial wafer is essential. The mechanical properties of silicon at room temperature, the silicon is a brittle non-malleable material, but at temperatures above 700-800 ℃, the silicon and has a clear thermoplastic, under the stress will show plastic deformation. Tensile stress greater than silicon shear stress, so the process is prone to the fragmentation.

Some types of components need epitaxial substrate epitaxial film thickness of the epitaxial layer also will continue to increase

As the semiconductor industry, IC scale has been expanded, the quality of the substrate sheet manufacturers are increasingly high  Diamond blade . Requires not only high-quality  cutting tools  polished surface with crystals, while some types of components need epitaxial substrate epitaxial film thickness of the epitaxial layer also will continue to increase. In previous years the thickness of the epitaxial layer epitaxial  abrasive wheels  is about 30, is now mainstream epitaxial thickness increased to between 50-60. Increasing the thickness of the epitaxial layer epitaxy, epi chance of defects increases. In order to solve the slip lines produced after epitaxial defects, all manufacturers put a lot of research.

Chamfering wafer processing step marks the level of technology

Wafer chamfering, also known as a full circle of silicon , silicon is an essential step of the normalized form . In a sense, it has chamfered wafer processing step marks the level of technology . The purpose of the chamfer is to reduce silicon  synthetic diamond , to prevent cracking of silicon , to improve the yield , when the epitaxial silicon to prevent curling and slip lines , to improve the quality of  Diamond blade  important role .  Abrasive grinding wheel  main silicon materials in foreign companies have also adopted the relevant units . Previously used in China and silicon wafer chamfering machine chamfering wheel lines imported from Japan , the manufacturing technology are " patent ." Now , wafer chamfering machine and grinding wheel China has succeeded in the trial and has been used in production . Chamfer with a diamond wheel only wafer manufacturing and use , to talk about some understanding and experience . Wheel base design and main parameters plated metal bonded diamond abrasive each species , have their own type of matrix design , wafer chamfering with a diamond grinding wheel is no exception. Silicon wafer with a diamond grinding wheel , silicon qualified edges must be rounded end face without chipping, to achieve this purpose , the wheel base body structure is a key factor.

Chamfer grinding wheel grooves on the quality of life as well as the impact has to be formed on the wafer edge profile requirements

Grinding wheel is a major material wafer processing, is currently in the purchase of grinding wheel, grinding wheel manufacturers generally require customers to provide their own wheel design drawings, and wheel design and wafer chamfer outline the pros and cons of great  cubic boron nitride . A better design not only improves the grinding wheel of life, but also to ensure the stability of product quality.  grinding wheel  wheel grooves on the impact of the general quality of life of our customers have been placing orders for wafer edge profile provides a good requirements, such as SEMI standard or profile half-width of the chamfer 11 °, or require a  abrasive wheels  profile widths, etc. . Therefore, the shape of the grinding wheel groove designed according to customer requirements, so that the chamfered wafer after processing to meet customer requirements. According to the author of these years of work experience, first in customer satisfaction guaranteed under the premise of the specific parameters for the design of the grinding wheel groove following three ideas: coarse grinding down groove bottom radius than the fine groove bottom circle down large number of specific arc radius, according to the amount of sperm removal down to develop.

Without the magnetic properties of granite, is widely used in production of precision measuring tools and instruments and the base platform

With the precision and ultra- precision processing technology, with high hardness, high wear resistance , low thermal expansion coefficient , are not electrically conductive , non- magnetic properties of granite, is widely used in production of  abrasive grinding  and instrument platform and the base , ultra- precision machine tool bed and rails , spindle, spindle box and workbench. The traditional processing methods granite widespread low processing efficiency and quality problems . Belt grinding is developed in the sixties and advanced machining methods. It has a high processing efficiency , " cold " grinding , grinding speed and stability,  abrasive wheels  , grinding and low cost , in the machinery manufacturing plays an increasingly important role , is now widely used in ordinary metals , difficult to machine metals plane , inside and outside the circle , the processing of complex shaped surfaces . Abroad in granite, marble, ceramic , glass and other  abrasive grinding  materials aspects of belt grinding process carried out some exploratory research . In this paper, abrasive belt grinding technology in the hard stone processing applications were reviewed . Belt grinding characteristics compared with the ordinary grinding wheel , abrasive belt grinding has the following salient features.

Grinding is a very important machining a class method, and is ultra-precision machining and finishing basic and preferred processing method

Manufacturing in the production process , not only to consume large amounts of limited resources , while also pollute the environment . Faced with the need for sustainable development of human society , the implementation of green manufacturing  Polycrystalline diamond  . Grinding is a very important machining a class method , and is ultra- precision machining and finishing basic and preferred processing method, widely used in industry . While also grinding machining the greatest impact on the environment and resources as a process . Own manufacturing abrasive article , the abrasive in the processing of the consumption of energy caused by  Synthetic diamond  consumption , as well as the extensive use of the grinding process and the resulting powder and fluid noise are all produced resources and the environment Yan Tong effects . China is the world abrasives production and  abrasive wheels , thus establishing grinding green degree evaluation system to improve grinding green degree is significant. In this paper, based on the literature review , analysis of the grinding process of the green requirements, a comprehensive study of the grinding process of the green characteristics and its influencing factors , to establish a grinding green degree evaluation index system and summarized for the Environment, energy and resources.

By wheel size and the change in processing stone finish, causes wear of the grinding wheel

Based on the experimental study, by wheel size and the change in processing stone finish, causes wear of the grinding wheel, the factors that affect the gloss level, in order to  synthetic diamond  the grinding of granite. Using two different size but the same size and shape of shaped resin wheels, two different hardness granite  cubic boron nitride  in a  Diamond blade , by measuring changes in the size and stone wheel gloss, of the grinding wheel wear and gloss effect factors, has been in the granite grinding wheel radius compensation process values ​​to improve the efficiency and accuracy of the grinding stone, stone processing equipment to promote the CNC industry applications.