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Why Superabrasives?


Super abrasives are tools

used in precision grinding. Superabrasive materials attach to a wheel to make

Superabrasive grinding wheels. The reason some abrasives are Superabrasives is due to

their extraordinary hardness, unparalleled performance, and longevity.


WHAT ARE SUPERABRASIVES?


Abrasives that belong to the Superabrasive family includes,Industrial diamonds: an

industrial diamond is a non-gem quality small diamond that is for abrasives, cutting, and

drilling tools.


Cubic boron nitride (CBN): Usually called CBN it is the second hardest cutting tool

material after a diamond.


Polycrystalline: Is an abrasive material that has a multiple collection of crystal

grain structures with individual orientations


CVD Diamond: These are synthetic diamonds made by a process known as chemical vapor

deposition.CVD diamonds grow from a hydrocarbon gas mixture. They are extremely hard,

have a high thermal conductivity that is five times that of copper. They also have

broadband optical transparency, are chemically inert, and only reach graphitization at

very high temperatures.


Nanodiamonds: These tiny diamonds are the product of a controlled explosion.

Sometimes called a detonation nanodiamond (DND) or an ultradispersed diamond, as this is

how they form.


INDUSTRIES THAT USE SUPERABRASIVES


A great number of industries use Superabrasive grinding wheels and the coated

abrasives subsection of the abrasives industry continues to grow. Industries that are

prime buyers of Superabrasive grinding wheels are:


Aerospace


Automotive


Medical


Electronics


Composites


Oil Industry


ADVANTAGES OF SUPERABRASIVES


The advantages of Superabrasive grinding wheels are more than extraordinary hardness,

unparalleled performance, and longevity. These three features of Superabrasives are the

core of many advantages manufacturers gain by

an aggregation of services that normal abrasives simply cannot deliver.


These include,


Less expensive tooling and fixturing costs


More wheels on the spindle, smaller wheels, multiple operations


Less floor space needed for manufacturing


Virtual elimination of wheel wear


Automated CNC machines, less labor intensive operations requiring less training


Consistent surface speed from part to part


Better overall throughput with fewer machines needed


Improved Material Removal Rates, Lower Per Part Abrasive Costs and higher speeds


With Superabrasives, production increased by automated CNC equipment, industries have

found one way to compensate for the lack of availability of skilled labor. With fewer

machines needed, so is fewer workers. With Superabrasives CNC, automation is more

concerned with defining a manufacturing process using machine capabilities and

mechanization. There is less concern on operator technique. A properly defined process,

combined with automatic loaders make for equipment that is almost running itself.


INDUSTRY OUTLOOK


Future growth of the abrasives industries will primarily be in Superabrasives.

Currently, research and development of Superabrasives are taking place in the following

areas:


Custom designed “hard to grind”? materials in an increasing number of industries


Creep or deep feed grinding


High-speed, high-performance grinding of hardened steel


Form grinding, sometimes with electroplating, in high precision, high-removal, and

high-surface quality applications


CNC-control of line grinding machines


In a nanotwinned crystalline structure, neighboring atoms share a boundary, the way

neighboring apartments do. And like some apartments, the twins mirror each other.

Typically, to make a substance harder, scientists decrease the size of the grains, which

makes it harder for anything to puncture it — small grains equals less space between

them for any point to enter. But the process hit a wall: in anything smaller than about

10 nm, inherent defects or distortions are nearly as big as the grains themselves, and

thus weakens the structure.


But the nanotwinning also makes substances harder to puncture, and in the case of

boron nitride, maintained that characteristic strength at sizes averaging about 4 nm,

explains Tian. And as a bonus, the cubic boron nitride was stable at high temperatures

as well.


"In our nanotwinned cBN, the excellent thermal stability and chemical inertness

are maintained with hardness competitive to or even more than diamond, making it the most

desirable tool material for industry," says Tian.


He anticipates that, with further research, the product will be comparable in price

to the softer, commercial forms of cubic boron nitride that are currently available.

Probable uses include machining, grinding, drilling and cutting tools, as well as

scientific instrumentation.


Articles About cutting tools


1 Material Properties and Performance Considerations for High-Speed Steel Gear-

Cutting Tools


Users of gear-cutting tools probably do not often consciously consider the raw

material from which those hobs, broaches or shavers are made. However, a rudimentary

awareness of the various grades and their properties may allow tool users to improve the

performance or life of their tools, or to address tool failures. The high-speed steel

from which the tool is made certainly is not the only factor affecting tool performance,

but as the raw material, the steel may be the first place to start.






2 Cutting Tools Now


The cutting tool is basic to gear manufacturing. Whether it's a hob, broach,

shaper cutter or EDM wire, not much gets done without it. And the mission of the tool

remains the same as always; removing material as quickly, accurately and cost-effectively

as possible. Progress in the field tends to be evolutionary, coming gradually over time,

but recently, a confluence of emerging technologies and new customer demands has caused

significant changes in the machines, the materials and the coatings that make

cutting tools.






3 Cutting Tools Roundup


The cutting tool industry has undergone some serious changes in the last couple of

years in both technology and the way the industry does business. The emerging technology

today, as well as for the foreseeable future, is dry cutting, especially in high volume

production settings. Wet cutting continues to be as popular as ever with lubrication

advances making it more economical and environmentally friendly. There has also developed

a process called "near dry cutting." this process offers many of the benefits

of fluids while eliminating many of hte associated problems.






4 Big Gears Better and Faster


Indexable carbide insert cutting tools for gears are nothing new. But big gears have

recently become a very big business. The result is that there's been a renewed

interest in carbide insert cutting tools.






5 High Speed Steel: Different Grades for Different Requirements


Hobs, broaches, shaper cutters, shaver cutters, milling cutters, and bevel cutters

used in the manufacture of gears are commonly made of high speed steel. These specialized

gear cutting tools often require properties, such as toughness or manufacturability, that

are difficult to achieve with carbide, despite the developments in carbide cutting tools

for end mills, milling cutters, and tool inserts.


When considering the use of CBN (cubic boron nitride) grains in an aerospace part

grinding process, the first questions that come to mind may be associated with the

grinding conditions and machine capabilities. It’s commonly assumed that CBN grinding

wheels need very specific operating conditions that only a re-tooled or new machine can

achieve. It’s also typical to think that those conditions are completely different from

the ones used by conventional grinding wheels. However, depending on the bond system,

some of the conditions may resemble those suitable for conventional wheels.






The first thing to determine when considering a CBN wheel is whether it will bring

any advantage to the current process. A cost analysis should be completed to make this

determination. In other words, how many parts can be ground using the CBN wheel and what

is the cost? This information can be used to make a cost/piece analysis, which can be

used for comparison to the current wheel (usually a conventional wheel) to determine if

there is value in incorporating the CBN wheel. After cost justifying the use of a CBN

wheel, it is helpful to look at the different bond options in order to optimize the

grinding process.


The most common bond systems for CBN wheels are resin, vitrified and electroplated

matrixes. Depending on the grinding conditions, each system has its own unique

requirements which will allow the wheel to achieve optimal performance.


RESIN BOND


Features: Resin is a bond that gives up easily and it is the most forgiving bond

among all. One downside of this bond is that resin does not do well if the grinding

conditions generate too much heat. Since the CBN grain is held in place by a mechanical

method, a resin bond tends to release the CBN grain before it dulls, so the wheel will

keep its cutting ability, but may never use the CBN grain completely.


Dressing Conditions: The wheel can be dressed outside or inside the machine. It is

usually done by using another

grinding wheel
such as silicon carbide, which trues the CBN wheel slowly. A white

stick made of Alox could be used to open the structure again after truing the wheel.


Grinding Conditions: Resin bonded wheels can be run wet or dry. The wheel speeds

range from 30 to 40 m/s when using coolant, and from 10 to 15 m/s when running in dry

conditions without the use of coolant. However, running a dry process can have a negative

effect on wheel life.


Cost: The cost of the wheel is based not only on the CBN concentration and wheel

size, but also on the thickness of the abrasives layer (usable layer). In many cases it

is possible to reuse the core of the wheel, but that can depend on the size of the wheel

and if the core material is reusable, such as steel. In some cases the actual technology

or manufacturing process doesn’t allow for reuse.


The History Of Diamond Jewelry


We all know that diamonds have been here longer than we have, but when exactly were

they first discovered? More importantly, when were they first used for jewelry? By taking

a quick look at the history of diamonds we will be able to learn a bit more about how

diamond jewelry came to be.


India – Where it All Began


Diamonds are located all around the world, but for our intents and purposes, our

story begins in India. This is because the first diamond is believed to have originated

from this particular country. At the time, they were valued not for their beauty or

durability but for they’re ability to refract light. This made them ideal for talismans

and decorations. As the times changed, diamonds were sought out for different purposes.

During the Dark Ages people believed that diamonds had medicinal value. The diamond later

evolved from a medicinal object into an item of value during the Middle Ages.
  • Létrehozva: 21-11-24
  • Utolsó belépés: 21-11-24

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