What is Grinder sanding disc?

background

Grinder sanding disc are made of natural or synthetic abrasive minerals that are bonded together in a matrix to form a grinding wheel.

Although such tools may be familiar to workers at home factories, the majority of the tools are developed and used by the manufacturing industry, so the public may not know them.

In this field, the sanding disc has been around for more than 150 years.

For manufacturers, concrete sanding disc provide an effective way to shape and finish metals and other materials.

Abrasives are often the only way to make parts with precise dimensions and high quality surface finish.

Today, grinding wheels are found in almost every manufacturing company in the United States. These wheels are used to cut steel and masonry, sharpening, drill bits and many other tools, or to clean and prepare surfaces for painting or plating.

More specifically, the accuracy of the automotive camshaft and jet engine depends on the use of the concrete grinding disc.

Without them, it is impossible to produce high-quality bearings. If there are no metal sanding disc to form and finish the parts, new materials such as ceramics or material composites will not be possible.

Sandstone is probably the earliest type of abrasive, an organic abrasive made of quartz particles bonded together with natural cement.

It is used to smooth and sharpen the flint on the shaft. By the early 19th century, emery (a natural mineral containing iron and corundum) was used to cut and shape metals.

However, the quality of the corundum is mixed, and the problem of importing it from India before it was discovered in the United States has prompted efforts to find more reliable abrasive minerals.

By the 1890s, people’s research had produced silicon carbide, a synthetic mineral that was harder than corundum.

In the end, the manufacturer came up with a way to produce a better alternative – artificial corundum or alumina.

In the manufacture of this bauxite derivative, they developed a more reliable abrasive than natural minerals and silicon carbide.

Research on synthetic minerals has also led to the production of so-called superabrasives. In this category, the most important is synthetic diamonds and a mineral called cubic boron nitride (CBN), which is second only to synthetic diamonds in hardness.

Today, development continues, and seed alumina has just been introduced.

In the history of the entire grinding wheel, the adhesion of the abrasive particles together has proven to be as important as the abrasive particles themselves.

The success of the cutting wheel began in the early 1840s when a rubber or clay-containing adhesive was introduced. By the 1870s, a binder with a vitrified or glassy structure was patented.

Since then, adhesives for cutting wheel have been constantly improving.

Wheels are available in a variety of sizes ranging from less than .25 inches (0.63 cm) to a few feet.

They are also available in a variety of shapes: discs, cylinders, cups, cones and rounds that are contoured at the periphery.

While many techniques, such as bonding an abrasive layer to the surface of a metal grinding wheel, are used to make the grinding wheel, the discussion is limited to Grinder sanding disc consisting of vitrified materials contained in the bonding matrix.

To make a metal sanding disc, all ingredients must be mixed together.

Some manufacturers simply mix all the materials in one mixer.

Others use a separate step to mix the abrasive particles with the binder, transfer the wet abrasive to a second mixer containing the powdered binder, and then tumble the mixture. Next, a grinding wheel is formed in the forming step: the ingredient mixture is poured into a mold and compacted by a hydraulic press.

raw material

The grinding wheel consists of two important components: abrasive particles and bonding materials.

Typically, the additives are mixed to produce a grinding wheel having the properties necessary to shape a particular material in the desired manner.

The abrasive particles constitute the central part of any metal sanding disc, and the hardness and friability of the abrasive material will significantly affect the behavior of a given wheel.

The hardness is measured by the relative scale developed by the German mineralogist Friedrich Mohs in 1812.

On this scale, the hardness of the extremely soft talc and gypsum is 1 and 2, respectively, and the hardness of corundum and diamond is 9 and 10, respectively.

Fragility is the degree to which a substance is easily broken or comminuted.

The design of the Grinder sanding disc takes very carefully into account the fragility of the abrasive (which varies with the nature of the material being ground).

For example, diamond is the hardest material known, but it is an unwelcome steel abrasive because it undergoes a destructive chemical reaction during the cutting process.

The same is true for silicon carbide.

On the other hand, alumina has a better cutting effect on steel than diamond and silicon carbide, but it has a poor effect on cutting non-metallic materials.

If the choice is correct, the selected abrasive that will shape the particular material will retain its brittleness when it is ground: the grinding will cause the abrasive to continue to break along the clean, sharp lines, so throughout the grinding process Keep sharp edges. This gives the wheel a unique feature that it becomes sharp during use.

Although bonded abrasives were originally made from natural minerals, modern products are made almost exclusively of synthetic materials.

The bonding material holds the abrasive particles in place and leaves a gap between them. The manufacturer of the diamond cutting disc specifies the hardness of the grinding wheel and should not be confused with the hardness of the abrasive particles.

A binder that causes the abrasive particles to break easily is classified as a soil binder. A key that limits grain breakage and allows the wheel to withstand large forces is referred to as a hard bond.

Usually, the soil wheel is easy to cut, the surface finish is poor, and the service life is short.

On the other hand, harder grinding wheels have a longer service life and produce a higher surface finish, but they do not cut well and generate more heat during the grinding process.

The bonding matrix to which the abrasive particles are fixed may include various organic materials such as rubber, shellac or resin; and inorganic materials such as clay may also be used.

An inorganic binder having a glassy or glassy structure is used for a sharpening wheel of a home-type grinding machine, and a resin binder is used for a masonry or a cutting wheel.

Generally, vitrified binders can be used for fine-grained grinding wheels required for precision machining.

Resin binders are typically used with coarse particles and are used in heavy metal removal operations such as casting operations.

In addition to abrasives and bonding materials, the concrete sanding disc usually contains other components that create holes in the grinding wheel or chemistry when grinding special materials with special abrasives.

An important aspect of a sanding disc that can be produced or altered by an additive is porosity, which also contributes to the cutting characteristics of the grinder sanding disc.

Porosity refers to the open space in the bond that accommodates small pieces of metal chips and abrasives produced during the grinding process.

Porosity also provides a path for transporting fluid that is used to control heat and improve the cutting characteristics of the abrasive. There is not enough porosity and the spacing between the abrasive particles,

A variety of products are used as additives to create the proper porosity and spacing.

In the past, sawdust, broken shells and coke were used, but today, materials that evaporate during the firing step of manufacture (eg, naphtha-wax) are preferred.

Some wheels will accept other materials to aid in grinding.

These include sulfur and chlorine compounds, which inhibit micro-welding of metal particles and generally improve metal cutting performance.

process

Most of the metal sanding discs are manufactured by cold pressing in which a mixture of various ingredients is press-formed at room temperature.

The details of the processing vary widely depending on the type of wheel and the practice of each company.

For mass production of small wheels, many parts of the process are automated.

Mixed ingredients

1 Prepare the grinding wheel mixture First, select the exact amount of abrasive, bonding material and additives according to the specific formulation.

A binder is added, typically in the case of a vitrified grinding wheel, a water based wetting agent to coat the abrasive particles. This coating improves the adhesion of the grain to the adhesive.

The binder also helps the wheel retain its shape until the bond cures.

Some manufacturers simply mix all the materials in one mixer. Others use a separate step to mix the abrasive particles with the binder.

Wheel manufacturers often spend a lot of effort to develop a satisfactory mixture.

The mixture must be able to flow freely and distribute the particles evenly throughout the metal sanding disc structure to ensure uniform cutting action and minimal vibration during rotation of the grinder sanding disc during use.

This is especially important for large cutting wheel that may be up to several feet in diameter, or for wheels that are different in shape from the familiar flat plate.

forming

2 For the most common type of grinder sanding disc, pour the disc, a predetermined amount of the grinding wheel mixture into a mold consisting of four parts: a round pin of the same size as the shaft hole (central hole) of the finished grinding wheel; the wall thickness is 1 The inch (2.5 cm) outer casing is about twice the thickness of the required wheel; there are two apartments that are shaped and finally molded, and the wheel is fired in an oven or furnace.

The calcination melts the binder around the abrasive and converts it into a form that resists the heat and solvent encountered during the grinding process.

The finishing step after firing may include reaming the cutter shaft (center) hole to an appropriate size, correcting the thickness of the side of the grinding wheel, balancing the grinding wheel and adding a label.

After forming and final forming, the grinding wheel is fired in an oven or furnace.

The calcination melts the binder around the abrasive and converts it into a form that resists the heat and solvent encountered during the grinding process.

The finishing step after firing may include reaming the cutter shaft (center) hole to an appropriate size, correcting the thickness of the side of the grinding wheel, balancing the grinding wheel and adding a label.

The circular plate has a diameter and a shaft hole size equal to the diameter of the grinder sanding disc. A variety of methods are used to evenly distribute the mixture. Typically, the straight edge pivots about the central mandrel pin to spread the mixture throughout the mold.

3 Use a pressure of 100 to 5000 pounds per square inch (psi) for 10 to 30 seconds, then use a hydraulic press to compact the mixture into the final shape of the wheel. Some manufacturers use gauge blocks between two panels to limit their movement and determine a uniform thickness. Others control the thickness of the wheel by closely monitoring the consistency of the mixture and the pressure of the press.

4 After removing the mold from the press and removing the grinding wheel from the mold, place the grinding wheel on a flat heat-resistant bracket.

The final shaping of the wheel may occur at this time. All work at this stage must be done very carefully, as the wheels can only be held together by temporary binders.

At this stage, the lighter wheels can be lifted by hand. Heavier cargo can be lifted with a hoist or carefully slid over the vehicle for transport to the kiln.

shooting

5 Typically, the purpose of firing is to melt the binder around the abrasive and convert it into a form that is resistant to the heat and solvent encountered during the grinding process.

A wide variety of furnaces and kilns are used to polish the grinding wheel, and the temperature varies greatly depending on the type of bonding.

Wheels with resin binders are typically sintered at temperatures between 300 and 400 degrees Fahrenheit (149 to 204 degrees Celsius), while wheels with vitrified binders are at temperatures between 1700 and 2300 degrees Fahrenheit (927 to 1260 degrees Celsius). sintering.

finishing

6 After launching, move the wheel to the finishing area where the shaft hole is reamed or cast to the specified size and the wheel circumference is concentric with the center.

Some steps may need to be taken to correct the thickness or parallelism of the sides of the wheel, or to create a special profile on the side or circumference of the grinder sanding disc. The manufacturer also balances the large grinding wheel to reduce the vibration generated when the grinding wheel rotates on the grinding machine. Once the wheels receive the labels and other marks, they are ready to ship to the consumer.

QC

The concrete sanding disc has no clear performance standards. In addition to grinding wheels that contain expensive abrasives such as diamonds, the sanding discs are consumable items and the rate of consumption varies widely depending on the application. However, manufacturers voluntarily accept many domestic and global standards.

Trade organizations representing some manufacturers in the highly competitive US market have developed standards covering issues such as abrasive grain size, abrasive labeling and safe use of concrete sanding disc.

The degree to which the quality of the wheel is inspected depends on the size, cost and end use of the cutting wheel.

Typically, wheel manufacturers monitor the quality of raw materials and their production processes to ensure product consistency.

Special attention should be paid to metal sanding disc larger than six inches in diameter, as if the wheel breaks during use, it may injure people and equipment.

Each large vitrified cutting wheel is inspected to determine the strength and integrity of the bonding system and the particle uniformity of each wheel. Acoustic testing measures wheel stiffness; hardness testing ensures the correct hardness of the bond; rotation testing ensures sufficient strength.

future

Changes in manufacturing methods will determine the future demand for all types of metal sanding disc.

For example, the trend in the steel industry to use continuous casting as a means of manufacturing steel has greatly reduced the industry’s use of certain types of grinder sanding disc.

Manufacturers’ drive for higher productivity is the result of market predictions, indicating that the market has turned from concrete sanding disc made from traditional alumina abrasives to grinder sanding disc made from new forms of synthetic abrasives such as seed alumina and cubic boron.

nitride. Similarly, the use of advanced materials such as ceramics and composites will increase the demand for new types of sanding disc.

However, the transition to new abrasive minerals has been hampered by the fact that many manufacturing equipment and many industrial processes are still unable to effectively utilize newer (and more expensive products). Despite the trend, traditional abrasives are expected to continue to be used in a variety of applications.

However, competition from multiple alternative technologies may increase.

Advances in cutting tools made of polycrystalline superabrasives (fine grain crystalline materials made of diamond or cubic boron nitride) will make this tool a viable option for forming hard materials.

Moreover, advances in diamond film chemical vapor deposition will affect the need for abrasives by extending the life of the cutting tool and expanding its performance.

BINIC-abrasive grinding wheel manufacturers – If you have questions about these products or any abrasives, our sales and technical experts will be happy to help you. You can send a message in the contact form below.

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