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
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:
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.
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.
Future growth of the abrasives industries will primarily be in Superabrasives.
Currently, research and development of Superabrasives are taking place in the following
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
"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
Articles About cutting tools
1 Material Properties and Performance Considerations for High-Speed Steel Gear-
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
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
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.
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