Cubic boron nitride(CBN) Applications

CBN abrasive grinding performance is excellent, not only capable of performing grinding hard materials processing, improve productivity, and is conducive to strictly

control the shape and dimensional accuracy of the workpiece, but also effectively improve the quality of the grinding of the workpiece, significantly increased After

grinding the workpiece surface integrity, thus increasing the fatigue strength of parts, extended service life, increase reliability, coupled with cubic boron nitride

abrasive production process in terms of energy consumption and environmental pollution than conventional abrasives production as well, Therefore, the expansion of

cubic boron nitride0) abrasive production and application of a mechanical application of the machinery industry development trend.
1. Tungsten, molybdenum, tungsten and other high-speed steel, especially vanadium steel, cobalt alloy, special high-speed steel tool sharpening and coarse.
(2) by the heat-resistant steel, stainless steel and high hardness alloy steel precision parts made of fine grinding and finish grinding. These parts with ordinary

abrasive abrasive due to excessive consumption, or blunt, but can not achieve high accuracy.
3. The local thermal stress and thermal shock sensitive materials (such as cast magnets, ferrite) parts grinding.
4. Large precision parts (Machine Tool, precision machine screw) fine grinding and finish grinding. These artifacts are often due to the high temperatures caused by

grinding larger thermal deformation, thereby failing to obtain high accuracy.
5. In the automatic and semi-automatic machines for mass production of the workpiece (instrumentation and miniature bearings parts) of fine grinding and finish

grinding.
6 Requirements abrasive edges with good retention of complex surface parts (gear shaper cutters, broaches, precision gears, cam, punch) grinding.
7. Thread cutter and thread gauges (taps, thread roller, thread plug gauges, etc.) type surface grinding.
8. Heat-resistant steels difficult to machine the workpiece super finishing.
9. Other hardened tool steel honing.
Cutting applications
PCBN inserts fine car with hardened steel
Machining of hard cast iron and gray cast iron
Boring holes casting speed
Reaming holes hardened steel or hard castings
Material removal
Using PCBN tool finishing of hardened steel, and its work harder than 45HRC, the best results. Its cutting speed is generally 80 ~ 120m/min, the higher the hardness of

the workpiece, the cutting speed should take a low value, such as car 70HRC hardness of the workpiece, the cutting speed should choose 60 ~ 80m/min. Finishing depth of

cut in 0.1 ~ 0.3mm, the feed rate at 0.05 ~ 0.025mm / r, finishing the workpiece surface roughness Ra0.3 ~ 0.6μm, dimensional accuracy up to 0.013mm. If a good

standard rigid CNC lathe, PCBN tool rigidity and sharp edge, then finishing the workpiece surface roughness up Ra0.3μm, dimensional accuracy up to 0.01mm, can be

achieved with CNC grinding machining level. If the machine rigidity, the choice of cutting speed is low, the selection of fine cars PCBN composite blade may

intermittently surfaces. Finishing allowance is generally about 0.3mm, before quenching to maximize the dimensional accuracy and low thermal deformation, cutting

margin in order to ensure uniform fine car, extending the life of the PCBN cutting tool. Finishing cutting fluid is generally not, because at higher cutting speeds, a

lot of cutting heat away from the chip, rarely stay in the surface affect the surface quality and precision. Finishing blades should use high strength and toughness to

the 80 ° diamond blade tip radius of 0.8 ~ 1.2mm, between the tool edge protection, need to use a fine whetstone chamfering. Finish turning of hardened workpiece is a

new technology, process testing to be done prior to the implementation, use and workpiece material, hardness and size of the same bar, in the same machine for

finishing or roughing test, the key is to experiment with the cutting tool parameter selection and process systems have sufficient rigidity. The process is currently

the country has adopted, such as FAW Group with PCBN tooling carburizing (58 ~ 63HRC) of 20CrMnTi transmission gear shift fork groove, using the process parameters are

Vc = 150m/min, f = 0.1mm / r, ap = 0.2 ~ 0.3mm, achieved by turning instead of grinding.
Processing of iron
Turning hardened steel with PCBN tools, require quenching hardness higher than 45 ~ 55HRC, machining of hard cast iron, as long as the level of hardness of medium

hardness (45HRC), will achieve good processing results. Such as automobile engine cylinder head on the exhaust valve seat is the use of copper, molybdenum, high-

chromium alloy cast iron material, the hardness of generally about 44HRC, the seat of the hole using the countersink (hinge), the car two processes , mostly in the

private automatic on-line processing, and carried a gun hinge hole catheter. Cutting used as: Vc = 71.6m/min, Vf = 26.5mm/min, ap = 1.0mm, using BC broaching oils,

processed since the adoption of PCBN cutting tools with carbide inserts previously used a variety of processing compared to the average durability of the tool 1200,

the machined surface roughness is Ra0.4μm, swing differential valve seat surface, the milling of cast iron
High-speed milling of gray cast iron, generally roughing can certainly use class K carbide, silicon helium finishing ceramic blade available. Such as a blade with 8

end mills use only installed on the two symmetrical PCBN inserts and cutting speed increased by 4 times, the result is the same metal removal rates while cutting force

declined by 3/4, tool life and machining quality than the former. Right pearlite cast and chilled cast iron, also should adopt PCBN cutting tools for high-speed

processing, comparison with other tool materials, can improve the cutting speed, longer tool life and reduce the surface roughness. Boring bar at high speed using

paired panels with single PCBN Boring boring compared good balance, thus increasing the rigidity of the boring bar, in a given feed, the use of twin blade boring holes

PCBN achieve high metal removal rate and surface quality. Currently there are more engine manufacturer of the cylinder block cylinder bore (or cylinder) finishing PCBN

cutting tools have been used. Such as Shanghai Volkswagen and FAW Group's engine plant, cylinder bore fine boring PCBN inserts are used and automatically compensates (

υc = 500m/min, f = 0.2mm / r, ap = 0.1mm). So out of the cylinder bore machining high precision, dimensional stability, and high efficiency, long tool life. For

boring holes, although ceramic or blade coating can be used, but the blades should be a negative rake angle, which will increase the cutting and chip resistance, easy

to produce vibration of the long boring bar. If using PCBN cutting tools for high-speed boring, its bore surface quality, high production efficiency. This kind of hole

machining the workpiece should adopt CBN electroplated reamer. The reamer is its hardness of 42HRC 9CrSi No. 45 steel or stainless steel as the base, and a cutting

portion having a front and rear guide, the matrix must be high precision manufacturing, design should be reasonable. Reamer as its front section with a diameter

smaller than the guide portion of the cutting edge diameter of 0.04mm, the length of the cutting area to the hole depth is greater than the workpiece, the latter is

greater than the length of the guide length of the cutting area, the diameter should be smaller than the diameter of the cutting blade 0.02mm. Reaming in order to be

able to flush chips and cutting fluid cooling and lubricating the machined surface, the substrate reamer opened two deep spiral groove. If a factory machining hardened

steel workpiece hole f12.06 ± 0.05mm, hardness 45HRC, Bottom size f12 ± 0.01mm, cylindrical bore as required 0.005mm, surface roughness Ra0.2μm. Using a group of

five of the electroplated CBN reamers after processing, to achieve better economic results. Some engine manufacturers, diamond or CBN electroplated reamer on the

cylinder block main bearing hole honing reaming, honing replace the original, so that processing efficiency increased by several times, and the quality and stability.

Used with a positive rake angle of PCBN tool, choose the appropriate cutting parameters, namely Vc = 100m/min, f = 0.05 ~ 0.2mm, ap = 0.1 ~ 0.2mm, using extreme

pressure coolant emulsion or oil, processed Austria austenitic stainless steel (45HRC), high temperature alloy steel, high manganese steel, high strength steel and

high nickel alloy steel and other materials, obtain higher machining efficiency and surface quality.
Grinding
 cBN materials in addition to the tool used to make, but its biggest application areas or CBN abrasive made for fast and efficient grinding and honing, grinding

efficiency can greatly improve the accuracy and quality of its grinding up a notch.
Grinding auto parts - camshafts and crankshafts
CBN wheel bore Grinding Application
With CBN grinding wheel gear
Application CBN abrasive machining difficult materials and hard work surface
Automotive engine camshaft having a plurality of cams, cam kibble after quenching and grinding cams that affect the quality of key processes. Are generally used by

imitating shaped grinding, the workpiece speed increase is limited, the workpiece is easy to produce grinding burn crack, using shaped grinding by imitating its cam

surface contour curve by the wheel diameter to the size of the impact, it is difficult to ensure correct the contour curve. Production Practice has proved that when

the wheel diameter is large, grind cam lean, when wheel diameter hours, grind cam fat, only when close to or equal to the diameter of the grinding wheel cam cam roller

diameter (usually f570mm), its copying the error approaches zero, the cam surface grind cam profile curve of the cam close. In actual production, the use of wheel

diameter are generally from the D600 (or 610) is used D500, and the ideal wheel diameter (570) differ very much, so a majority of the total production of the camshaft

cam curve exceeded. To solve this problem, we rely on the use of imitation cam grinder CBN grinding wheel, CBN grinding wheel diameter can be made of the D575, CBN

abrasive layer thickness of 4 ~ 5mm, its smallest diameter grinding wheel D565, grinding diameter range although only 10mm, but the number was equivalent to tens of

grinding parts ordinary piece wheel, not only to ensure proper cam curve, but it does not produce the phenomenon of grinding burn. Such as internal grinding efficiency

has been low, the main reason is grinding speed, grinding wheel materials and rigid rod problem. Production process used in the dressing wheel, replace the wheel time

work accounted for almost one-piece 1/3 to 1/5. If the inner circle or trench with CBN electroplated grinding wheel and the wheel speed, increasing the grinding rod

diameter, can be an appropriate increase in the workpiece speed and feed rate, not only to ensure the hole (arc) diameter, width size and shape bit accuracy, surface

roughness and to avoid burns, but also can be multiplied to improve processing efficiency and reduce processing costs. Such as domestic factory processing an annual

output of 600,000 sets of textile machinery bearings, grinding f15.5 +0.04 hole and the adjacent arc groove, in the past with chromium corundum (GG) wheel, two steps

were required in two M224 internal grinding machine processing, its slot (arc) diameter difference and the size of the hole is difficult to ensure concentricity and

low efficiency, the use of CBN grinding wheels, bold a grinding rod, improved feed, saving the trimming and replacing the wheel of the time, solve the original

problem. Later changed to hole, ditch while grinding, grinding rod that is installed in two wheel, the grinding efficiency by 1 times, saving a grinder. The processing

of the workpiece surface roughness Ra0.63μm grinding process parameters used: V sand = 36m / s, V2 = 19m/min, f rough cut = 1μm / r, f fine cut = 0.5μm / r, light

grinding time t = bs, emulsion concentration of 10% values. Gears grinding in the past is the use of a single tooth and multiple tooth surface grinding, surface

grinding, although single tooth can obtain higher precision, but low efficiency, high cost, multi-tooth grinding, although high production efficiency, but its

processing single tooth grinding poor quality ratio. The use of CBN grinding wheel, either single-or multi-tooth grinding, tooth grinding, electroplating or vitrified

CBN grinding wheel for grinding, the effect is extremely significant:
CBN grinding wheel can be made with high precision tooth, because high durability, less frequent dressing, without constantly adjust the machine, to obtain a stable

tooth Gallery, lead and pitch accuracy.
Can be achieved with a high speed grinding tooth surface grinding feed rate, low roughness and will not burn, can improve the grinding efficiency in the conditions to

obtain a high precision gears (6 to 7).
CBN grinding wheel, long life, good grinding performance, saving replacement wheel dressing machine adjustment and testing, and many artifacts auxiliary time.
On hardened steel or chilled cast iron bore honing, CBN honing stone can be used for high-strength, high hardness and high heat-sensitive alloy steel, stainless steel,

heat-resistant steel and alloys, should adopt high hardness, high strength CBN wheel, using extreme pressure emulsion or liquid cooled high-speed grinding. For longer

rail surface or complex surfaces, cam shaft cam grinder etc. CBN grinding wheel should be used.
Machining
CBN materials either produced or produced abrasive tool, used in high-speed cutting or grinding, can receive improve product quality, improve processing efficiency,

shorten the processing cycle and reduce processing costs and other significant effects. Therefore, in the processing, and vigorously promote the CBN tool (grinding) is

to improve the manufacturing technology with powerful measures. However, if popularized use, there are many problems. In order to better promote the use of production

CBN cutter (grinding) with, you should do the following tasks:
Action
Achieve joint development of three-point line, that CBN - Tool Manufacturing - user or CBN and tool manufacturing - machine tools - user applications jointly developed

CBN
Research
At present, a lot of CBN materials manufacturers, production is also a lot, but not much high-quality, CBN cutting (grinding) with the stability of the user less. The

reason is mainly machining department CBN expensive knife (grinding) with a lack of choice and use of knowledge, the procurement of CBN Tools effectiveness much, in

its austerity conditions, will not dare to invest in technology test.
Quality awareness
Courage to improve manufacturing technology in order to solve this problem, only the CBN tool (grinding) with Institute (The) active-depth machinery manufacturing

production units, production efficiency and quality selection weaknesses and already has or is easy to create a point CBN processing conditions , jointly developed

with the user CBN negotiated and signed application contract. Tools developed by the test unit is responsible for the CBN gratis knife (grinding) with the user's

responsibility to provide the necessary conditions to organize production test pilot. This played a multi enthusiasm, select the tool from the CBN quality

manufacturing, will to the best, the fastest speed, users from preparation to the experimental conditions used, to see the results of the target to achieve the

contract, do not spend testing fee will be solved production problems, it is easy to promote. The Tool Academy (the) supply in the future also gradually recovered

profits, as long as the two sides have maintained mutual benefit, cooperation relations will further consolidate. I plant is the use of this approach with a number of

research institutions have developed many new technologies. Many in machining processing difficulties, although CBN tools available to solve, but the condition is not

domestic Which can be done alone, because not all CBN tools have unique and universal processing capacity. We have also used the CBN inserts fine boring boron liner,

its effect is not better than the new ceramic blades.
Quality reasons
The reasons are many, such as CBN quality, content, branding specifications and binders are suitable boron cast iron. As CBN abrasive grinding effect of factors

influence even more, in addition to its quality of raw materials, proportion and abrasive manufacturing technology, there are conditions of use and technologies. Such

as grinding speed (high speed grinding applications speed), grinding rigidity, no vibration, automatic feeding and dressing fine compensation mechanism, appropriate

grinding parameters and coolant, etc. These are important complementary factors, by the parties concerned concerted efforts to improve their quality of their products,

promote each other in order to make CBN tools and special equipment for the production successfully. Users want to use with the effectiveness of CBN tools, therefore,

requires tools manufacturing units, in addition to CBN tools and to improve manufacturing techniques, the quality of the product should also establish clear criteria

and methods of identification, the distribution of certain performance parameters, such as the CBN tool content and brand, hardness and abrasive CBN precision,

concentration, etc., on the basis of production use tests to give full play to the user's experience in the production of different cutting parameters and machining

coolant obtained results were analyzed, the CBN tools are qualitative improvement. CBN tools, scope, conditions of use and application of technical support (such as

equipment and coolant, etc.), the user can correct selection and use of CBN tools. 21st century is the era of high technology, the product must be a high-performance,

high-quality, no market, business vitality. Therefore, we should increase the level of manufacturing technology as soon as possible, while promoting the use of CBN

tools to improve manufacturing technology is a powerful measure, which requires not only the competent authorities of the strong funding and support, organized,

planned and gradual promotion of technical support and CBN tools use, but also require the user to the courage to accept new materials, new technologies change the

past, outdated production methods and management concepts, namely knife (grinding) with indicators of consumption costs are very low, we can only total product cost

about 1/100, rather than to improve production efficiency and product quality assurance prevail, this will limit the quality and efficiency of the knife (grinding)

with a production capacity of applications and advanced equipment to play. Practice has proved that, CBN cutting (grinding) with the effectiveness of the process can

not only improve the quality of products, but also can improve economic efficiency.