The correct choice of abrasive

Overview faced due to blasting construction productivity and environmental stakes so well-known characteristics of abrasive blasting has become in today's business

environment to survive and maintain a competitive advantage specific demands. Introduction sandblasted surface is re-established protective paint systems

To step. Over the years many tests concluded: providing stability in blast cleaning the surface of the anchor-like appearance of the coating application can get the

corrosion resistance and high durability. In order to obtain the proper surface roughness must select the appropriate requirements engineering polish

abrasive grinding . In some cases, because the sand will damage the surface residues of the degree of cleaning, polishing must consider not strong blasting particles. Today's

business environment for quality assurance and environmental requirements are very strict, so familiar with the characteristics of the abrasive blasting is critical.

Unlucky

There is no one kind of blasting abrasives suitable for all construction work, fortunately, there are many different types and grades of abrasive, to ensure the

project is completed. Learning the characteristics of each type of abrasive can help you choose the more efficient and interests of abrasive blasting.
When selecting the desired abrasive, it must take into account the characteristics of each. These include abrasive hardness, shape, size, color, weight, chemical

composition, availability, cost, and environmental factors, to choose the best according to each item.
Hardness The hardness of the abrasive particles determines the ability to form etching or sandblasting the surface of the substrate to form a specific anchor-like

appearance. Determine abrasive method is Mohs hardness scale hardness. The scale ranges from 1 to 10, 1 being the most flexible (Mica) 10 represents one of the hardest

(

Diamond). Generally reach anchor-like appearance sandblasting pellets hardness was 6.0 or higher. But there are some requirements in the range 3.0 to 4.5 using soft

pellets, these pellets were not etched glass or steel surface, but will remove foreign soil, provides surface

Cleanliness, mainly for the substrate surface do not want to damage or sand blasting particles or residues be damage to the environment surrounding the area. Soft sand

pellets usually used around the bearing or other vulnerable machines range. Hard abrasive grit and steel shot is with Rockwell

C notation hardness. Hardness in the range between 42-65. Etching the surface of the steel grit and steel shot in the steel surface dents.
Shape The shape of the abrasive is not the same, there is angular, massive, semi-circular shape or spherical. There are sharp edges on the substrate in clearing

angular abrasive substances or dirt adhering closely to clean the highest rate. A sharp edge angular abrasive surface of the steel can anchor-like appearance of the

paint

The attachment provides excellent mechanical properties. In addition to very difficult to remove the dirt, the bulk abrasive cleaning can guarantee a good rate.

Abrasives or semi-spherical indentation in the surface, which is mainly used to increase the surface hardness of the abrasive.
The size of the clean abrasive size and the rate of formation of anchor-like appearance. Sieving through the United States or particle diameter size of France decided

to differentiate tablets
Abrasive grinding generally divided into four sieve to 325 sieve, the smaller the size, the larger abrasive particles. 8-16 grade pellets is very rough, mainly for difficult

cleaning or need deeper anchor-like appearance of the surface; 20-40 level for general purposes; 80-120 grade for polishing metal surfaces.

Round or spherical sand particle diameter pellets to distinguish through the grades, the size range between 0.070 -0.660 feet. Uniform level to ensure that the size of

the abrasive blasting machine through accurate flow measuring valves, uniform level of grit in order to protect the base

Stable metal surface roughness.
If you consider is color selection abrasive type, color is not very important, but in some cases also a key factor. After blasting the surface of the residue will

affect the appearance. Black abrasive because of the difficulty reflected sunlight, less dust than light, interior lighting is needed

This is especially when blasting area important. If in a confined area or areas for maintenance construction, easy to completely remove the abrasive from the aesthetic

point of view is very important to choose the color of abrasive.
Weight or gravity will affect the weight of the abrasive surface cleanliness and surface roughness. By the weight in pounds / cubic foot, said referring to the

proportion of the particle density than the major means heavy weight. The same pressure conditions, heavy pellets made deeper anchor-like appearance. Ratio

Significant less abrasive dust generated, light weight pellets impact the substrate is small, mainly used for light sandblasting or polishing to remove burrs. Chemical

composition in order to ensure the compatibility with the substrate, the chemical composition of the abrasive must be considered. When blasting, the spray sand

Child will be embedded in the substrate or leave residues, will be on the protective coating system damage. If the stainless steel substrate using iron blasting

particles embedded corrosion electrode formed on the substrate. Availability must ensure that the chosen blasting particles have sufficient supply

, Easy access, to ensure the successful completion of the project. To ensure the best engineering results, not recommended way to replace the abrasive. Many abrasive

is a natural byproduct of ores or other industries, is not easy to ensure timely delivery of large quantities.
Cost Cost is abrasive key factor in the project. Generally speaking, by the supplier to the construction site from the freight decide abrasive choice. Abrasive damage

rate is also important. Cupboards or by sandblasting sand recovery system between the full re-use, reducing the high recycling

Rate abrasive costs. Blasting pressure recirculation rate, hardness, ductility, and determined by the size of abrasive.
Environmental impact on the environment is to determine the final choice of abrasive elements. Include: sandblasting workers respiration. Workers in the sandblasting

process must use respiratory equipment, and monitor the entire blasting process. When the blasting area with poor ventilation, you must use the correct dust

Soil recycling equipment to reduce workers face the dust. It should also be taken into account abrasive dispersed into the soil, enclosed area should be considered

toxic paint additional safety and engineering control measures. Abrasive
    Abrasive directories listed below is just normally use abrasives, not all, the purpose to provide readers with more information, and to arouse the reader's

curiosity looking around for suitable abrasive. Familiar with the performance characteristics of each type of abrasive to ensure the success of the project to provide

good

Good start.
Silica abrasive silica sand is an inexpensive, in many countries, many places you can get. Ores relatively sharp, more rounded sand. Mohs hardness of 6-7, can be

formed on the surface of the substrate etching or anchor-like appearance, a variety of sizes, brown or tan, can pass

Over recycling use, containing 95% -99% silica (SiO2). Because of the danger of silicosis, you must take special sandblasting process control. U.S. Occupational Safety

and Health National Business Association (NIOSH) recommended standard PB-246-697 Part 6 point 2 a

Description: "no silicon controlled blasting will cause silicosis hazard, special attention must. Silica sand or other materials containing more than 1% free silica,

must be prohibited as abrasive blasting process used in the blast." And further that: "The most effective and direct exclusion silicosis

Disease risk approach is replaced with a material of low toxicity free silicon, sandblasting process should consider the silicon content of less than 1% of free

alternatives. "
The utility industry slag by-product slag, massive, free silica content of less than 1%. Mohs hardness of 6, is formed on the substrate surface can be etched, or

anchor-like appearance, with green glossy black, a variety of sizes, mainly composed of silicon oxide, aluminum oxide and iron oxide

Composition, can be recycled several times, but generally one-time use, is inexpensive abrasive. Copper Copper is copper slag slag industrial by-products, block, free

silica content of less than 1%, Mohs hardness of 6, is formed on the substrate surface can be etched, or anchor-like appearance, due to

Proportion of embedded substrate Assembly, black with gray gloss, available in various sizes, are inexpensive abrasive.
Nickel Nickel slag slag are by-products, block, free silica content of less than 1%, Mohs hardness of 6, is formed on the substrate surface can be etched, or anchor-

like appearance, a variety of sizes, can be recycled many times, but generally one-time use, is a low abrasive.
Cross Stone Cross Stone is a natural mineral, cusp-like, free silica content of less than 1% of alumina and iron oxide, Mohs hardness of 7, can be formed on the

surface of the substrate etching or anchor-like appearance, can be recycled many times use, but for outdoor and sandblasting cabinet and there is back

Closing occasionally blasting systems use only once, with moderate and small size. Ceramic Ceramic is specialized in producing abrasive, cusp-shaped, free silica

content of less than 1%, was dark brown / gray, Mohs hardness of 7, a variety of sizes, to the substrate surface erosion

Engraved or anchor-like appearance, can be repeatedly recycled.
Peridot Peridot is a natural mineral, cusp-like, free silica content of less than 1%, Mohs hardness of 6.5, can be formed on the surface of the substrate etching or

anchor-like appearance, pale green, there are a variety of sizes, the main ingredient is silicon oxide, magnesium oxide, iron oxide, can be more

Times recycling use, but for outdoor blasting and sandblasting cabinet and a recovery system can only be used between blasting off.
Zircon is a natural mineral zircon, cusp-shaped, free silica content of less than 1%, the Moh hardness of 6.5, formed on the surface of the substrate can be etched, or

anchor-like appearance, consisting of zirconium silicon, brown, its rapid cutting, mainly in the blasting cabinet and a recovery system sandblasting

Occasional use.
Alumina ceramics are specialized in manufacturing abrasive, cusp-like, free silica content of less than 1%, black, Mohs hardness of 8, a variety of sizes, the surface

of the substrate can be etched, or anchor-like appearance, can be repeated Recycling, because of fast cutting, low dust, high

Costs, mainly in the blasting cabinet and a recovery system used in sandblasting room.
Is specialized in producing glass beads ceramic abrasive, spherical, free silica content of less than 1%, white, Mohs hardness of 6, a variety of sizes, may be formed

on the surface pits can be recycled many times, because of its fast and clean mainly in the blast cabinet and cost recovery system has

Using conventional sandblasting room, used to increase surface hardness and deburring.
Garnet Garnet is a natural mineral, cusp-shaped, free silica content of less than 1% red, Mohs hardness of 7.5, a variety of sizes, the surface of the substrate can be

etched, or anchor-like appearance, can be recycled many times , because of its fast cutting, low dust, high costs

This, mainly in the blasting cabinet and a recovery system used in sandblasting room.
Specializing in the production of silicon carbide SiC abrasive, cusp-shaped, free silica content of less than 1% black, the Mohs hardness of 8.5, a variety of sizes,

the surface of the substrate can be etched, or anchor-like appearance, can be more secondary recovery, because fast cutting, low dust

High costs, mainly in the blasting cabinet and a recovery system used in sandblasting room.
Walnut shell walnut shells are agricultural products, block, free silica content of less than 1%, Mohs hardness of 3, no etching of the substrate surface, black, a

variety of sizes, for deburring, cleaning electrical components, precision thread or bearing the surrounding area. Jade

Corn cob cob grain rice grain agricultural products, block, free silica content of less than 1%, Mohs hardness of 4.5, no etching of the substrate surface, black, a

variety of sizes, for cleaning electrical components , aluminum mold, precision thread or bearing the surrounding area

Domains. Specializing in the production of plastic particles in the plastic abrasive particles, blocks, free silica content of less than 1%, Mohs hardness of 3-4, the

plastic particles are soft, no etching of the substrate surface, because of the high cost, mainly in the spray cabinet and sand blasting rooms have recycling systems

Used for cleaning the mold, thread and precision equipment area. Shot Shot specialized in manufacturing abrasive, spherical, free silica content of less than 1% of the

iron oxide component, Rockwell C hardness of 42-50, to the formation of dents on the surface, the number of recycling

Up to 100 times or more, the use of low cost, mainly used for rotating wheel blasting machine, also for other metals to provide surface hardness. Grit abrasive grit is

specialized in producing, cusp-like, less than 1% free silica content, composition is iron oxide, Rockwell C hardness of 42-62

, Recycling up to 100 times more than the frequency of use, low cost, mainly in the blasting cabinet and a recovery system used in blasting rooms can also be mixed

with steel shot, by rotating the wheel blast machine to achieve special anchor-like appearance. This paper summarizes the total abrasive blasting views

Purpose is to inspire readers to describe consciously find more suitable project is completed around the abrasive. This article describes the various abrasive has its

advantages and disadvantages, and is currently on the market there are more good performance abrasives. To win in the competition, cost-effectively complete the

project

Must be familiar with each of the abrasive. Select the appropriate abrasive, costs and productivity are important, but environmental considerations are also essential.

Monocrystalline diamond tool machining

A single crystal diamond tool of election materials and Orientation
Produce single crystal diamond cutting tools Step 1 job is the choice of materials, depending on the processing conditions, methods, materials can not only choose the right

tool to ensure the quality of raw materials and avoid wasting diamond increases processing costs. General tool with diamond material

Requirements crystal integrity, no cracks, crystal surface should be as flat as possible, the minimum diameter should generally be not less than 4 mm, a weight of 0. 7

~ 3 ct.
As the tool requirements, or diamond shape of the decision, and sometimes you need to split the original stone diamond. Complete cleavage with parallel diamond,

diamond carbon atom between carbon atoms is larger covalent forces combined. However, the structure of the diamond

Certain direction, as applied in a direction parallel to the octahedron face a certain force, the diamond is easily broken, mainly because of the diamond crystal bond

connected to this surface is relatively small. So choose the cleavage planes of diamond segmentation of the original stone, split method shown in Figure 1.

On the need to split out a diamond called the kerf slot or nicks. The trick is to split the slit and know where you want to cut much deeper. To grind a slit-quality

single crystal diamond tool, you must master the technique of single crystal diamond crystal orientation. This is mainly

Is due to the anisotropy of single crystal diamond determined by the characteristics of diamond each side
Hardness up varies greatly. To select the appropriate crystal planes and crystal orientation as the tool rake face, flank, namely the Diamond blade to achieve the best wear

resistance and processing properties. Diamond crystal interface in each direction on good ground, the lowest rate of crystal surface grinding, crystal surface,

followed by plane

Grinding rate is highest. Since crystal surface hardness is too high, grinding difficult and microscopic intensity is not high, easy cleavage, it is difficult grind

sharp edges. Good ground plane in the direction of crystal surface grinding rates than high nearly doubled, but different crystal faces of diamond breakage chance to

apply various types

Number of motor integrated protection. For different motors can simply adjust the threshold accordingly.

Method diamond tool orientation

Currently, there are three main ways crystal orientation: artificial visual crystal orientation, X-ray laser crystal orientation and crystal orientation.
Artificial visual crystal orientation
The method is based on the natural crystal external geometry, surface growth, corrosion characteristics of each crystal face relationship between the geometry, by

virtue of the operator-term work experience, by observation and experiment made rough crystal orientation. The method is simple, easy, do not need to borrow

Aid equipment, but the directional accuracy of the results is poor, the operator experience requirements, and for processed and lost natural crystal crystal

characteristics of the cutting tools can no longer carry out artificial visual orientation.
Laser crystal orientation
Laser crystal orientation is preferably coherent laser beam to the surface of the Diamond blade crystal in different directions present on the surface of the crystal growth

process in the formation of crystal planes of regular shape and microscopic pit pattern formed on the screen is reflected to the characteristics diffracted light

image. But the real

On occasion due to outside interference factors, the natural formation of rules and microscopic crystal faces crystal grain pits are often not obvious or impossible to

observe. Therefore, in this crystal orientation prior to artificial erosion through proper to form characteristic morphology.
X-ray crystal orientation
Since the X-ray wavelength of the lattice constant, when the X-ray crystal or through the surface is reflected back from the crystal, the diffraction occurs. This

principle has been developed using a dedicated X-ray crystal orientation instrument. This method of high accuracy crystal orientation, but due to X-rays

Human body has certain hazards, the need to focus on when in use to protect workers.
Crystal diamond tool to select
Diamond anisotropy, so not only the crystal surface hardness, wear resistance difference is the same crystal plane of the wear is different in different directions. If

the inappropriate choice of crystal orientation, even choosing the right crystal surface, grinding efficiency will be greatly reduced. The same time as anti-diamond

crystals

Compressive strength than the tensile strength is 5 to 7 times, so the grinding process to select the grindability of the crystal plane orientation, while cutting edge

facing the grinding wheel speed to the positive direction (i.e., taking the inverse mill) to ensure grinding efficiency and reduce the extent of cutting edge micro-

cleavage.
Diamond grinding tool breakage
Diamond tool wear mechanism is more complex, can be divided into macro-and micro-abrasion wear, the former mainly mechanical wear, which is dominated by thermal

chemical wear. Diamond grinding tool breakage common form for the former flank wear, flank wear and edge chipping. In the single-crystal

Diamond tool sharpening process, requires the wear to the grinding tool to meet the requirements, but if it produces unwanted wear sharpening may damage the already

good before the flank. The edge crack (ie chipping) is on the edge of the local stress exceeds the diamond tool

Occurs when the capacity is generally a diamond crystal (111) cleavage plane of the micro-damage caused. In the ultra-precision machining, diamond tool edge radius of

the cutting edge is relatively small, which itself is hard and brittle materials, and because of its anisotropy and (111)

Surface prone to cleavage, with vibration and grit grinding wheel cutting edge of the tool impact effect, it is often accompanied produce chipping.

Single-crystal diamond tool plane selection

Diamond crystals are cubic plane, since each crystal form and surface atomic arrangement atom density difference and the distance between the different planes,

resulting in a natural diamond crystal anisotropy, so the performance of the diamond crystal surface only of the physical and mechanical different performance

, Ease of manufacture and service life which are not the same, the microstructure of the crystal surface damage strength are also significant differences. Microscopic

diamond crystals Hertz strength test method used to determine, since the diamond is a typical brittle material, the strength values ​​are generally larger deviation, the

main

Depends on the shape and distribution of the stress distribution range, so suitable for use probability theory to analyze. When the effect of stress is the same, (110)

crystal plane maximum probability of damage, (111), followed by (100) crystal plane of the minimum probability of breakage. Ie external force, (110)

The most easily damaged planes, (111) crystal face, followed by (100) the most difficult to break. Although the (110) crystal plane grinding is higher than the (100)

crystal plane, but the experimental results show that the (100) crystal face and the other plane has a higher resistance to stress, corrosion, and thermal degradation

capability. Integrated micro combined strength

Considered together with the (100) plane to do before and after the cutting tools flank, easy sharpening tool edge high-quality, easy to produce micro-chipping.
Normally be carried out according to requirements of the tool planes of the single crystal diamond tool selection. In general, if the request to obtain the highest

strength diamond tool, should be used (100) surface as the tool before the flank; if required resistance to mechanical wear diamond tool, then select

With the (110) crystal face as the tool before the flank; if required chemical wear resistant diamond cutting tool,Diamond blade it is desirable use of (110) crystal plane as the

tool rake face, (100) crystal face as the flank, or the front , are used flank (100) crystal plane. These requirements need the help of crystal

Body orientation technology to achieve.

Single crystal diamond tool

In the ultra-precision machining, to ensure the quality of the machined surface of the main factors in addition to high-precision machinecutting tools , ultra stable

processing environment, the quality of the tool is also an important aspect. Natural diamond with high hardness, good wear resistance, high strength, good thermal

conductivity, and

Non-ferrous low coefficient of friction and excellent anti-adhesion, good corrosion resistance and chemical stability, can grind extremely sharp blade is considered to

be the best ultra-precision cutting tool material, especially in the field of mechanical processing ultra-precision processing sector has an important

Status and are widely used.
The physical properties of single crystal diamond
Carbon atoms, a single diamond crystal, the crystal structure belongs to a face-centered cubic equiaxed crystal (an atomic crystal highest density). Carbon atoms in

the diamond bond of connection between sp3 hybridized covalent bond, it has a strong binding force, and directional stability.

It is the hardest known natural material, the hardness of up 10000HV, other physical properties see below.
Superiority
Because the physical properties of single crystal diamond itself, cutting knife is not easy to stick and BUE, good surface quality, processing non-ferrous metals, the

surface roughness up Rz0.1 ~ 0.05μm. Diamond also effective processing of non-ferrous metal materials and non-metallic materials,

Such as copper, aluminum and other nonferrous metals and alloys, ceramics, non-sintered carbide, a variety of fiber and particulate reinforced composite materials,

plastics, rubber, graphite, glass and various wear-resistant timber (especially solid wood and plywood, MDF and other composite materials).
Natural characteristics of single crystal diamond tool sharpening
Ultra-precision machining, single crystal diamond tool two basic contour accuracy and precision is the cutting edge of the Diamond blade edge radius. Aspheric lens processing

requirements of the arc tool edge with a roundness of 0.05μm or less, the processing of the polygon mirror with a 0.02μm edge straightness

; Blunt tool edge radius (ρ value) indicates the degree sharp edge of the tool, in order to meet a variety of processing requirements, the blade edge radius ranging

from 20nm ~ 1μm.

Single crystal synthetic diamond

synthetic diamond single crystal diamond tool with high hardness, high strength, good wear resistance, good thermal conductivity, chemical stability and good features, high-

quality knives can be sharpened blade is ultra-precision cutting tool materials.
Synthetic single polycrystalline diamond tool is mainly used for high-precision micro-abrasive mirror finish, such as DVD and digital camera lens detector with a plastic lens

grinding mirror finish.

Manufacture of monocrystalline and polycrystalline diamond tools

With monocrystalline and polycrystalline synthetic diamond manufacturing tools, most must rely on metal, ceramic or resin as adhesive carrier, therefore, diamond tool

life and efficiency except with the choice of diamond and bond related, but also depends on the diamond and binding agents

Bonding strength, but between the diamond and the carrier exists on the physical and chemical properties of a huge difference, so that the combination extremely

difficult. To this end, at home and abroad have developed a variety of diamond surface metallization technology, and strive to improve the diamond between the solder

and the metal carcass

Wettability and adhesion strength then to extend the life of the diamond tool.
Chemical gas and liquid processing technology (CVLT), available on the diamond crystal, powder, polycrystalline surface alloying treatment, is currently a new,

advanced diamond metal surface treatment technology.
1 Technical Features
The technology for all types of diamond surface alloying treatment of the various components, the main technical features:
1 Diamond Type: all kinds of diamond single crystal, polycrystalline, powder and CVD diamond films;
(2) surface alloying material: W, Cr, Ti, Ni, Co, Cu, etc., and good connectivity with the resin compound;
3 surface alloy film thickness: according to need up to 0.3 ~ 40μm;
4 a combination of the diamond surface film forms: covalent and metallurgical bonding.
(2) Applications
The technology applications include the following aspects:
1 polycrystalline diamond surface alloying
CVLT technology used in production of polycrystalline diamond surface alloy layer 15 ~ 40μm film, the sintered polycrystalline diamond or can be firmly welded to the

metal carcass. We have successfully used this technique on oil drill and mining tools, metal effect has reached America

State companies like GE metal film polycrystalline diamond level.
(2) single-crystal diamond surface alloying
CVLT technique using the single crystal diamond layer produced on the surface of the alloy film of 1 ~ 5μm, can greatly improve the single-crystal diamond sintered

compact, diamond grinding wheel tool life.
3 diamond powder surface alloying
CVLT technology for diamond powder has two main purposes, one in the diamond powder surface recombination layer of about 0.5μm (Ni, W, Cr) alloy film, this powder can

be used to produce diamond grinding wheel (metal bond and resin bond ) and diamond polishing belt, polishing

Disk, etc., in order to improve the adhesive properties of diamond and matrix. Second, the surface of the diamond powder composite layer (W, Co, Ti) alloy film, a

polycrystalline diamond produced using this powder, polycrystalline diamond can improve strength and high temperature stability.
4 activation organic single crystal diamond surfaces
CVLT technology using the single crystal diamond layer grown on the surface of the resin having an affinity group and a compound resin can improve the life of the

diamond grinding wheel.
5.CVLT technology can also be used in a variety of tool and die, metal parts surface hardening, lubrication, anti-corrosion, anti-oxidation treatment.