interlocution:
1, the concentration of metal binders, cutting pieces, grinding wheels. Some cutting chip suppliers said that the concentration is not high, about 30%, please Wang Gong to give us science popularization.
Answer: The concentration of metal binder is not high, the cutting blade grinding wheel hand tool is more, the power is small, (the finer the particle size, the lower the concentration, and the coarse particle size concentration will be higher).
2. Grinding cemented carbide workpieces of resin diamond grinding wheels, such as resin diamond grinding wheels
D300*T25*H127*X10, particle size 120#, wet-ground cemented carbide, how much is the recommended grinding wheel speed, feed amount, feed speed. There is also a trimming, is it recommended to use a white corundum grinding wheel, or a green silicon carbide grinding wheel?
Answer: The grinding wheel speed is less than 35, generally about 30, and the feed amount is generally 1 to 2 wires, according to different grinding conditions. Trimming is generally more with green silicon carbide, the general particle size is 120 # with the grinding than it is coarse with 80/100, 60 # can be, medium soft 1 or medium hard 1, medium soft 2 soft 3 can be, but the hardness of the soft 1 is the best, too hard then the speed is too slow.
3, foreign customers have asked about the bakelite matrix, the English name Bakelite, which is the bakelite matrix, compared to the aluminum matrix, what advantages does the steel matrix have, I hope that Wang Gong can also give us a popularization.
A: The bakelite matrix is formed after the hardening of phenolic resin and aluminum, and it has good elasticity and thermal conductivity.
4, metal binder grinding wheel, has been known to use electrical processing trimming, whether it can also be used corundum oil blade.
A: Yes, in fact, there are many ways of processing, electric processing, grinding, electrolytic grinding, free grinding, etc., generally corundum, oil stone can be, not too hard, trimming can not be too hard, and the trimmed grinding wheel must be low speed.
5, metal sintered drill, glass hole, how much is the recommended concentration?
A: This has something to do with granularity. Sintered drill bit 80/100, if the concentration requirements of the drill rock layer are relatively high, the harder the drill bit concentration is higher, the softer the concentration, the lower the concentration. Generally speaking, it is between 50-70.
6, resin, ceramics, metals, different binders suitable for what type of material?
A: The resin binder has a relatively weak holding force and is easy to fall off, generally using 1 type material (RVD material) or resin polycrystalline diamond (the synthesis time is short, and the aggregate formed is more). Ceramics generally use a type of better material, type one and a half or type two, normal words are type two yellow material, but not too durable, it is best to use type two material. Metal binders are generally used 2.3.4 type, metal binder formulations are copper-based, cobalt-based nickel-based, tungsten carbide-based and composite groups, its categories are more numerous. In general, the stronger the holding force, the higher the grade of diamond used for the binder. Metal binders are divided into metal sintering, as well as bronze binders (bronze binders are 8515, 8020 copper-tin alloy) the hardness is relatively low, and then up is iron-based, nickel-based, cobalt-based, and then up is tungsten carbide-
7. The influence of the linear speed of the grinding wheel on the effect of the grinding wheel
Answer: The linear speed of the grinding wheel has an optimal value, generally speaking, the speed is too low, the grinding is also very large, and the binding agent wears fast; too high the vibration of the machine tool is large, and it is not good for the diamond, and it is best to be appropriate. The general diamond grinding wheel is about 35 meters.
8. The production process of metal grinding wheel.
9, the initial rough processing of cast iron / steel parts can be used to replace cbn, as well as diamond honing processing engine cylinders; want to know in what kind of processing conditions, can be realized with diamond instead of CBN processing iron group metals.
A: Diamond can be processed into non-metallic hard and brittle materials (marble, granite, ceramics, wear-resistant materials, sandstone, gemstone, semiconductors, glass, etc.). It is non-metallic, except for iron, cobalt and nickel, which cannot be processed, and others can be processed. Because diamond is carbon, processing steel is prone to iron tricarbon reaction, that is, the strength of diamond will drop sharply, because iron cobalt nickel is its catalyst and solvent. Cast iron and iron itself are two different concepts, stainless steel has the lowest carbon content, cast iron has a carbon content of 2.46%, iron and carbon have been saturated, it will no longer react with diamond, so diamond can process cast iron molds, diamond (durable) and CBN (sharp) can be used to process cast iron. Why is honing processed with diamond? Because the diamond crystal shape is complete, the processing surface texture is better.
Processing tungsten steel: To be precise, tungsten steel is not steel but cemented carbide.
10. How is diamond typed?
A: You can do TI (cold punching) TTI (hot punching), the more standard is cold punching, hot punching.
TI (cold punching), the TI value of the diamond to characterize its impact toughness, take a certain amount of diamond specimen together with the steel ball into the specimen tube after the rated number of impacts after the impact into the inspection screen to measure its unfinished rate. TTI (hot punch) characterizes its thermal shock toughness, removes a certain amount of diamond in a furnace and heats it to 1100 °C for 20 minutes, then impacts and tests its unfinished rate. Now the industry believes that simply measuring the TI value or TTI value does not fully reflect the performance of the diamond, and the difference between TI and TTI can better characterize its stability. Due to the large number of internal impurity defects in low-grade diamond, a large number of "black spots" appear inside the crystal after calcination at 1100 °C, and the overall color of the single crystal becomes darker, indicating that the inside of the crystal has caused "internal injury" after calcination. Most of the single crystals will break after impact. However, due to the small number of internal impurities defects in high-grade diamonds, only a small area of "black spots" appear inside the single crystal after calcination at 1100 °C, and most of the single crystal calcination has not changed before and after calcination
(For example: Zhongnan 2120 2110:21 is the catalyst brand, 20 represents 20% of the unbroken after the impact)
11. Crystal form of diamond:
A: Crystal form: The particle size composition is divided into five pieces: basic grain, coarse grain, coarse grain, coarsest grain, fine grain, and finest particle. Micro powder generally does not exceed 2 times, crushing material does not exceed 2.5 times, and it will not work for a long time, and it will be scratched.
Type 1: needle flakes, dendritic, incomplete crystal form, (can detect bulk density, particle size composition, generally not strength detection)
Type II: isoseasonal, with partially intact crystal surface.
Three types: the intact crystal surface accounts for 70-80%, and a small amount of crystal surface has defects.
Four-type material: hexahedron, complete crystal form, good permeability.
12. What material is generally selected for the selection of raw materials for diamond tool grinding wheels?
Answer: The tool grinding wheel must have both strength and thickness, but also appropriate concentration, if too much sharp surface is worn, the strength is too high, then the top will not be too low, then the diamond is crushed as soon as it is ground, generally it is a two-type material, and the particle size is appropriately concentrated. The grinding wheel of korean (new Korea) grinding tools has a general crystal shape feeling, but the diamond is relatively thick.
Courseware:
The main component of diamond is carbon, graphite is the allotrope of carbon, graphite is a layered, hexagonal structure; diamond is a cubic structure, graphite into diamond requires 5-10 million atmospheres of pressure, 1300-1500 °C, (hexagonal boron nitride is a layered structure, is white graphite, hardness is very low, cubic boron nitride hardness are relatively high. ）
Natural diamond is colorless and transparent, light yellow is nitrogen-containing, green is iron-nickel-containing, impurities are mostly gray-green, diamond density is 3.52g/cm3, cubic boron nitride 3.48 g/cm3. Most of the synthetic diamonds are hexahedrons,
The faces in the rectangular box are the most fragile,
Comparison of diamond and cubic boron nitride properties:
CBN is not alkali tolerant and cannot be water-soluble and alkaline abrasives.
Slippery (talc) stone (gypsum) square (calcite) fluorite (fluorite) phosphorus (apatite) long (feldspar) topaz corundum diamond (Mohs hardness 1-10)
Thermal stability of diamond in different atmospheres:
The grinding wheel of the bronze binder will generally pass through inert gas or hydrogen, and if there is no protective gas, it is easy to fall off the ring. There are also diamonds with high temperature resistance and strength, diamonds containing boron, but after adding boron, it is easy to cause lattice radical changes, so the crystal form of boron-containing diamonds is generally not good.
Zhongnan material yellowing is because of nitrogen content, (Type Ia diamond is yellowish, contains flake nitrogen, generally natural, electrical insulator; type Ib is yellow with diffuse nitrogen (uniformly mixed inside), artificial; type IIa is more natural, conductive thermal conductivity is very good; IIb type light blue, contains very little nitrogen, conductivity is very good, semiconductor).
Comparison table of synthetic diamond varieties in various countries:
Resin binders are easy to fall off, generally using a type of material
Roughness: The surface quality of the workpiece after processing. It is generally denoted by Ra.
form:
The mesh size is approximately 15000 divided by the screen number = mesh size.
For example: R0.05→ ▽ 12→W5 (3-6), R0.8→ ▽ 8→100/120
<col>
granularity
Corresponds to the granularity number
45/50
46
140/170
150
50/60
60
170/200
180
60/70
70
200/230
200
80/100
80
230/270
240
100/120
100
270/325
280
120/140
120
325/400
325
Adjacent particle size generally does not cause scratches, but the resin grinding wheel corresponding to the finish particle size is generally to choose a little coarser, because the resin is easy to fall off, so the resin grinding wheel particle size should not be selected too fine, the selection is not sharp,
Diamond raw material picture analysis:
Zhongnan material, high-strength process yellow material, more transparent, concentration is better. Resin grinding wheels are required to be sharp.
Green material, iron nickel catalyst material is relatively green, opaque is low strength, is black material (time short, seven or eight minutes)
Number one is , hexahedral polymorphism.
Number two is the polymorph of a regular dodecahedron and two planes
Crushing material, with edges and corners, and there are not too many large particles, relatively sharp, coarse particle size generally needs such a crystal form.
Type 3 complete crystalline material and type 2 microfinding material
The crushing material is relatively sharp The length-to-width ratio is about 2:1
Zhongnan type, belonging to a type of better material, wear-resistant, pointed.