How to replace the worn drill

After some time working in the underground drill , drill scraper blade diameter becomes smaller, shorter, blunt , rock crushing capacity will become weak , slowing progress . Tags: geological coring drill concave three wings drill
Drill a certain time after the underground work , scraper blade diameter drill bit smaller , shorter, blunt , rock Crankshaft Grinding  crushing capacity will become weak , slow down progress ; cone bit due to the erosion of tooth wear , bearing damage , can cause cone rotation is not flexible or cone stuck, the torque increases, if not promptly fall from the cone accidents will happen ; diamond drill due to heterogeneity caused by the formation of PDC drill bits crack occurred on , off, off Similarly the drilling footage slower. To speed up the pace of drilling wells whole , must be replaced with the old drill , and drill a few hundred meters to several kilometers in the underground , how to replace the drill bit drilling workers do ?
When drilling rig power driven  hone tool  turntable, kelly , drill and drill bit rotates through the instrument to observe the work of the underground drill rig floor , after the comprehensive judgment, if deemed drill has been worn , replace the drill bit must immediately stop drilling . After stopping drilling, drilling fluid circulation to maintain a period of time , the purpose is to adjust the good performance of the drilling fluid , and the suspension in drilling cuttings out of the ground, the cycle of the new borehole wall remained stable , while also to carry out routine checks on drilling equipment . Workers drilling derrick crane use on the traveling block and hook, according to the height of the mast by column ( generally consisting of two or three drill ) from the entire drill string from the well . After the drill column in the order from the discharge in the derrick while the drill string downhole stone polishing pads  proposed , to use a pump to keep the annular space drilling infusion fluids , the aim of maintaining the liquid level does not fall within the wellbore so that a wellbore pressure to balance the formation pressure to prevent borehole collapse or underground formation fluids into the wellbore . Meanwhile, we should pay particular attention to the reduced diameter borehole drilling may occur card , the operator should be strictly controlled to improve speed. The entire drill wellbore , drill collars from the rear , while the need to replace the drill bit will play out , workers remove the old drill press drill fitted with a new column under the original order can be restored to the wells after drilling

Grinding wheel used to improve the performance of the basic parameters can not be discounted

Carry on the work of the grinding process , to choose the right material , depending on the hardness of the grinding wheel grain size of the workpiece, in addition to these commonly used during the grinding wheel a few basic parameters , but also pay attention to , so masonry saw blades   as to maximize the improvement of grinding efficiency.
Arc a diamond wheel in contact with the workpiece ( unit : mm).
2 . Wear ratio .
3 grinding energy . Is the energy per unit volume ( or weight ) of the metal consumed removed. Its value is smaller, the better the material can be grinding , metal removal rate is relatively higher .
4 diamond wheel line speed . ( Unit : M / S)
According to grinding machine spindle speed diamond wheel speed can be drawn , then the basis of its diameter , it can draw its line speed. Wheel manufacturers are generally of a standard line  granite core bits speed , i.e. the linear velocity , diameter, rotational speed are related.
5 in the axial cylindrical grinding feed rate ( Unit : mm / r)
According to the width of the wheel , using the appropriate amount of axial feed , in the process , you can ensure efficient grinding efficiency at the same time , to get better results. If coarse steel , feed rate of 30% to 70% of the width of the coarse castings , feed rate of 70 % to 80 % of the width , while grinding , feed rate , compared with 10% of the width to 30 %.
6 inner axial cylindrical grinding feed diamond grinding wheel  rate (unit : m / min). Axial and axial feed rate is the feed rate and workpiece speed related .
7 workpiece speed ( unit : m / min). This is the diameter of the rotational speed of the workpiece and the workpiece related .
Only in a variety of relevant factors are considered comprehensive , and will make the grinding wheel to achieve the best results....

The chemical composition of the diamond and the causes

Diamond is one of many married women must have a baby in mind, this is actually a diamond diamond. This diamond and diamond saw we say what does it matter? A senior quality natural diamond, a diamond for industrial use, poor quality, it may be artificial, but one thing wood band saw blades  is the same: their hardness. Diamond is one of the hardest metals, natural form so hard, but why such a beautiful stone?
First, the chemical composition of the diamond
To understand the formation of the first to know his diamond chemical composition. The chemical composition of the diamond is carbon, which is the only single-element in the gem. Is isometric crystal system. Crystal form mostly octahedron, rhombic dodecahedron, tetrahedron, and their poly shape. Pure colorless diamonds, the mixing of trace elements present different colors. Strong adamantine luster. 2.417 refractive index, dispersion medium, 0.044. Homogeneous body. Thermal conductivity of 0.35 cal / cm? Sec? Degrees. Thermal conductivity meter test, the reaction is most sensitive. Hardness of 10, is the hardest known mineral, quartz absolute hardness is 1000 times, 150 times corundum, fear, hit after hit will be broken along its cleavage. A cleavage completely. Density 3.52 g / cc. Diamond has a luminous, the  Plate Compactor sunlight, the night can emit phosphorescent light cyan. X-ray irradiation, emit blue fluorescence. Diamond is chemically stable at room temperature is not easy to dissolve in acid and alkaline, acid does not produce its effect.
Diamonds and similar gems, synthetic diamond distinction. The gemstone market common substitutes or fake colorless stones, colorless spinel, cubic zirconia, strontium titanate, yttrium aluminum garnet, yttrium gallium garnet, synthetic rutile. Synthetic diamond was first developed in 1955 by the Japanese success, but mass production. Because synthetic diamonds than the high cost of natural diamonds, synthetic diamonds on the market so rare. Diamond its unique hardness, density, and dispersion, the refractive index difference may be similar thereto gems. Such as: Fangzuan cubic zirconia and more colorless, strong dispersion (0.060), strong luster, density, 5.8 g / cc, weigh heavy hand feel obvious. Yttrium aluminum garnet dispersion soft, it is difficult to visually distinguish the diamond.
It has become the people who can stone polishing pads  own, wear mass gems. Diamond's culture and long history, more people today see it as a symbol of love and loyalty.
Second, the causes
These components together is how to become a diamond it? Modern science and technology, the means to explore the formation of diamond provides new ideas and methods. Diamonds are the hardest in the world, the most simple ingredients gem, which is composed of carbon, and a natural cubic crystal structure.

As abrasive wheel itself has high hardness and heat resistance

 As intense friction, leaving the grinding zone temperature is high. This will cause the workpiece to produce stress and deformation of the workpiece surface and even cause burns. Therefore, a  dry polishing pads lot of grinding coolant must be injected to reduce the grinding temperature. Also from the coolant and lubrication chip.
Grinding large radial forces. This will cause the machine - grinding wheel - workpiece system flexibility retreat, the actual depth of cut less than the nominal depth of cut. Therefore, the grinding will be completed when the light is not to be infeed grinding to remove the error.
After blunt abrasive, grinding force also increased, resulting in grain crushing or off, re-exposing the sharp abrasive grinding wheels  edge, this feature is called "self-sharpening." Self-sharpening of the grinding head in a certain period of time to normal, but over a certain working time should be performed after manual trimming, grinding force increases so as to cause vibration, noise, and damage the workpiece surface quality.
As abrasive wheel itself has high hardness and heat resistance, high hardness can be processed so grinding materials such as hardened steel, carbide, etc..
Determine the characteristics of  abrasive grinding wheels the grinding wheel and grinding grinding system can make even a trace cutting, general ap = 0.001 ~ 0.005mm; grinding speed is high, generally up to v = 30 ~ 50m / s; grinder stiffness; adopts hydraulic transmission, Therefore, grinding can be obtained economically with high precision (IT6 ~ IT5) and a small surface roughness (Ra = 0.8 ~ 0.2μm). Grinding is one of the main methods parts finishing.

Ultra-thin diamond grinding wheel series use

Thin diamond grinding wheel diamond grinding wheel is used on the basis of common technology, then after selection through the use of diamond powder metal contact made ​​of ways . A variety of hard concrete core bits  and brittle so it can cut grooving data , such as : a variety of silicon , germanium , ferrite, glass , lithium niobate , gallium phosphide ( diamond wheel ) , lithium tantalate , phosphorus arsenic gallium , gallium arsenide , all kinds of ceramics. Which has high strength and ultra-thin diamond grinding wheel tolerance , high precision, ultra-thin and other features .
 Ultra-thin diamond grinding wheel series is a fact that thin ring. Which will demand pick appropriate scale flange can use , through the use of edge wear after assuming full circle may have been destroyed after the blade , then it can be swapped into a smaller flange can be sustained by trimming after use can be described as very economical. Just simply use another fine grinding wheel flange, then we can get the best cut effect. So  diamond blade saws the use of diamond grinding wheel conditions are what it ?
1 cut diamond grinding wheel speed is necessary more than 80 m / s ;
2 cut diamond grinding wheel normal speed ( to be cut speed ) based on the information and cut precision cut demand conclude , usually 0.5 to 200 mm / seconds ;
 3 cut diamond grinding wheel when it is necessary to water cooling, cooling water flow rate is not less than 2.4 l / min ;
 4 cut diamond grinding wheel grinding wheel thickness and depth of cut based on information determined . Maximum depth cbn wheels  of 3 mm incision is usually within ;
 5 new sand grinding wheel before use is necessary to open with a special marking plate edge marking .
 6 films selected diamond grinding wheel , in order to ensure the best cut effect ( glass grinding wheel ) cut data based on different needs to select the appropriate grit size grinding wheel .

CBN grinding wheel dressing cycle is long

  CBN abrasive hardness higher than normal , high hardness means more sharp

and cutting stronger ; CBN has a higher wear resistance, means that it is

harder than ordinary abrasive wear ; ability  sds drill bit  to maintain the shape of CBN

abrasive high-performance one of the main characteristics of the abrasive ;

CBN high compressive strength , which means that in the harsh conditions of

use it can remain intact and not broken particles ; CBN has good thermal

conductivity , the grinding can be achieved when cold cutting .
1, high hardness, high toughness CBN human hardness only to diamond synthesis

of superhard material is much higher than the normal corundum and silicon

carbide abrasive , and thus has a flap wheels  better cutting ability , more sharp.
2 , high temperature resistance , good thermal stability .
3 , chemical inertness . 4 , good thermal conductivity . 5, the grinding

performance, good surface quality 6 , abrasion resistance and longer life.

CBN grinding wheel ratio up to 3500-5500 , a hundred times more than ordinary

high corundum grinding wheel , diamond grinding wheel 3-5 times higher than

that . 7 , environmental pollution, energy saving. Without too much powder

dust. 8 , high efficiency, good overall economic efficiency . Sharp grinding

, grinding force is small , CBN grinding wheel dressing cycle is long ,

finishing less the amount , the replacement for a long time ; long life

cycle, grinding ratio , getting a better economy, in use to maintain good

shape , without regular replacement wheel and wheel dressing , saving time ,

improving working conditions , is  stone drill bits conducive to the machining operation .
   Cubic boron nitride (CBN) is not suitable for grinding carbide and non-

metallic hard materials . In the grinding temperatures , CBN case of alkaline

aqueous chemical reaction occurs , CBN wheel at 300 ℃ alkaline solution will

be decomposed in boiling water to trace decomposition destroyed crystal

grains will result , so that when grinding only use oil-based coolant , not

water-based coolant.

The main mechanism of grinding wheel burns introduction

When the grinding wheel surface temperature , if the cooling measures is not good , it's easy on the workpiece surface ( from tens to hundreds of um um) occur secondary quenching and tempering . If the grinding wheel surface layer of the instant temperature exceeds steels AC1 point, the role of the secondary coolant quenched martensite , while  concrete saw blades in the subsurface due to temperature gradients , short time , only the formation of high-temperature tempering organization This makes the surface and subsurface between the tensile stress and the surface of a thin brittle secondary hardening martensitic , when can not afford , it will crack.
Heat treatment of
A ) residual austenite retained austenite grinding wheel grinding wheel grinding wheel because heat and pressure generated changes occur at the same time may be accompanied by tempering and grinding wheel surface cracks. Amount of residual austenite should be controlled within 30% .
2 ) carbon concentration diffusion layer nitrided layer carbon concentration is too high, easy to form a nitrided layer tissue or excessive free mesh carbide carbide . Because this substance extremely hard , the wheel grinding process may lead to local overheating tendencies and incidence surface tempering . Nitrided layer carbon concentration is too high, the surface will produce excessive residual austenite. Resulting in burns and cracks. Therefore, the surface carbon concentration increases, reducing the performance of the grinding wheel , the general surface carbon concentration should be controlled within the range of 0.75% -0.95 % .
3 ) carbide distribution should be diamond core drills  uniform carbide distribution and morphology , particle size not greater than the average diameter lμm; carbide morphology should be spherical , powdered or finely punctate distribution along the net , mesh or angular carbides are not allowed .
4 ) decarburization heat treatment . Surface or environmental cause improper surface oxidation , so that the workpiece will produce a thin carbon layer , this layer will cause decarburization soft wheel overload or overheating , resulting in surface tempering .
5 ) tempering the premise of ensuring the hardness , the tempering temperature is as high as possible a number , as long as some of the annealing time . This can improve the surface carburized hardened plastic , and the residual stresses are balanced or lower . Improving the abrasive tools  distribution of surface stress . This can reduce the probability of cracks occur workpiece , thereby improving the efficiency of the grinding wheel grinds the workpiece .
6 ) deformation should minimize heat deformation . This reduces the grinding wheel margin. If the heat deformation is too large, if the operation is not in the workpiece grinding wheel radial runout maximum at the beginning of the grinding wheel , grinding wheel each time point at which the grinding wheel is removed margin would not be normal, resulting in burns and cracks.