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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.

    • Creado: 23-11-21
    • Última sesión: 23-11-21

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