can be calculated by the finite element method of stress magnitude different speeds to simulate the failure process and improve the design.
2013年7月29日星期一
Abrasives
Outline
Abrasives
Abrasives [1], is abrasive and abrasive collectively, including abrasive products and abrasive products. Known as dental abrasives industry reputation. Commonly used
in the grinding or abrasive abrasive grinding tool as the machining of parts to be machined to a certain technology to achieve the
Requirements.
Abrasive Category
Wherein the abrasive products are mainly divided abrasive corundum and silicon carbide abrasive two categories, specifically, there are basically the following:
1, corundum abrasive, the main component of Al2O3, with medium hardness, toughness, particle Fengrui, relatively inexpensive, suitable for machining high tensile
strength of the metal. Microcrystalline corundum abrasives and black corundum abrasives are its derived varieties.
2, white fused alumina abrasive, slightly higher than the hardness of corundum, but poor toughness, easy to cut into the workpiece during grinding, good self-
sharpening, less heat, grinding ability, high efficiency. Chromium corundum abrasive is its derived varieties.
3, single crystal corundum abrasive material particles are composed of a single crystal, and has a good polygonal cutting edge, high hardness and toughness, grinding
ability, less grinding heat, the disadvantage is the high cost of production, yield lower, so the price is relatively high. Corundum abrasives also
Is a crystalline compound, slightly lower hardness, crystal size is fine, good wear resistance.
Monocrystalline corundum
4, black silicon carbide abrasive, green silicon carbide abrasive, abrasive cubic silicon carbide, silicon carbide abrasive cerium, etc., are silicon carbide abrasive,
the main ingredient is silicon carbide SiC, high hardness, brittleness, sharp abrasive grains, good thermal conductivity, strong wear resistance, more suitable for
processing hard and brittle
Metallic and non-metallic products.
Abrasives classification, development
Is for Abrasive grinding , grinding and polishing tools. Most of the abrasive is made of abrasive plus artificial abrasive binding agent, is also useful natural mineral
rock directly processed into natural abrasive. In addition to grinding and other metal processing machinery manufacturing industry has been widely used outside,
Also used in food processing, paper industry and the ceramics, glass, stone, plastic, rubber, wood and other non-metal materials processing.
Abrasive in use, when the blunt abrasive, because the abrasive agent or a combination of its own to break fracture, the abrasive grain from the partial or complete
loss, the working surface of the abrasive grinding emerging new cutting edge, constantly exposing new sharp or abrasive, so abrasive
In a certain period of time to maintain the cutting performance. This self-sharpening abrasive is abrasive tool compared with the general prominent feature.
As early as the Neolithic Age, humans had already started to process the application of natural stone knives, stone axes, bone, horn, and tools such as a tooth; 1872,
appeared in the United States with natural abrasives combined with clay firing ceramic grinding wheel; 1900, artificial abrasives
Advent of artificial abrasives manufactured using a variety of abrasive successively generated for the rapid development of grinding and grinding machines to create
the conditions. Since then, natural abrasive in the abrasive proportion gradually reduced.
Abrasives source of their raw materials, with natural and artificial abrasive abrasive categories. Commonly used in machinery industry is only natural abrasive
Whetstone. Artificial abrasive characteristics according to the basic shape and structure of the distinction between a grinding wheel, grinding, stone, sand tile (the
foregoing collectively referred abrasive) and coated abrasives
Five. In addition, it is customary also put abrasives abrasive as a class.
Bonded Abrasives are used by different abrasives can be divided into ordinary abrasive abrasive and superabrasive abrasive. The former corundum and silicon carbide and
other common abrasive, the latter with diamond and cubic boron nitride and other superhard abrasive material. In addition, there are some special varieties, such as
burning
Results corundum abrasive and so on.
By ordinary abrasive abrasive abrasive solid binding agent to form a certain shape common, and has a certain strength abrasive. Generally abrasive, binder and pore
structure, these three parts are frequently referred to as the three elements of abrasive.
Abrasive abrasive cutting action play. Binding agent is a solid form of the abrasive loose abrasive materials, with inorganic and organic types. Inorganic binder with
ceramic, magnesite, sodium silicate and the like; organic a resin, rubber and shellac. One of the most commonly used is a ceramic
, Resins and rubber binders.
Holes in the ground when debris from the role of the chip and the chip, and can accommodate coolant, helps grinding heat dissipation. To meet the requirements of
certain special processing, the pores can be impregnated with certain fillers such as sulfur and paraffin, so as to improve the abrasive performance. This
Kinds of fillers, also known as the fourth element of the abrasive.
Means a common abrasive abrasive characteristics of the project are: shape, size abrasive, grain size, hardness, organization, Velcro, adhesive and bonding agent.
Abrasive abrasive hardness refers to the external force from the abrasive surface of the shedding of degree of difficulty, which reflects the binding agent holding
abrasive
Intensity.
The hardness of the abrasive agent is added depends on the amount of binding and the density of abrasive, abrasive grains easily fall off indication low hardness; vice
versa, which means high hardness. Hardness level is generally divided into super-soft, soft, medium soft, medium, medium-hard, hard and superhard seven level from
these
Hierarchy can be further subdivided into a number of small magnitude. Abrasive hardness measurement methods are more commonly used hand cone, mechanical cone method,
Rockwell hardness measurement method and sandblasting assay.
The hardness of the abrasive and its dynamic modulus of elasticity has a corresponding relationship, which is conducive to the audio abrasive measured dynamic elastic
modulus of said abrasive tools. In the grinding process, if they are grinding workpiece material hardness, generally used in low hardness abrasive; contrary, the
choice of hard-
High abrasive.
Grinding of crude into tight, medium and loose categories. Each category can be further subdivided and number, with the numbers to differentiate between organizations.
Abrasives organization number greater share of the abrasive grinding smaller volume percentage, the wider the gap between the grains, which means that more loose
tissue. Conversely, tissue
The smaller the number the more tightly organized. Loose organization is not easy to use abrasive passivation less heat during grinding, the workpiece can reduce heat
deformation and burns. Tight organization abrasive grit easy to fall off, helps maintain the abrasive geometry. Abrasives organizations only
Manufacture of abrasive formulations are controlled by, generally do not make determination.
Edit this paragraph
Use
Grinding, polishing, grinding, cleaning, cutting, drilling.
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