This is a very real feeling for the application of grinding wheels. A deeper understanding of grinding systems.
"Grinding King" will give you an analysis of the manufacturing method of superhard abrasive tools from the grinding performance, and remind the brothers who only bury themselves in the formula. This might be a wake-up call.
High efficiency grinding technology is a necessary condition for advanced manufacturing technology, which completely solves the processing limitations of high precision and low efficiency of traditional grinding processing.
While obtaining high efficiency and high precision, it can also process various materials and shapes with high surface integrity and reduce costs. Under the present conditions of our country, it is of great significance to strengthen the research, popularization and application of high-efficiency grinding technology to improve the processing level of our country's machinery manufacturing industry and accelerate the development of new products. Nowadays, the application of superhard materials is increasingly extensive, and the implementation of high-speed and efficient grinding is the preferred processing technology for processing superhard materials and hard-to-cut materials. Due to the application of superhard abrasives, high
The development of high-speed, high-power precision machine tools and numerical control technology, the development of new grinding fluid and grinding wheel dressing and other related technologies, the application of high-speed ultra-high-speed grinding and high-efficiency grinding technology, the development of grinding automation and intelligence technology, make high-efficiency abrasive processing in the field of machinery manufacturing has a more important position, with good development prospects.
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"Grinding King" : The high-efficiency grinding wheel should have good wear resistance, high dynamic balance accuracy, crack resistance, good damping characteristics, high stiffness and good thermal conductivity, and its mechanical strength must be able to withstand the cutting force during high-efficiency grinding. High efficiency grinding wheels can use corundum, silicon carbide, CBN, diamond abrasive. Under the conditions of suitable binder and advanced manufacturing process, the production of abrasive tools can be used at speeds up to 125m/s.
The existing ceramic bonded grinding wheel is resistant to water, oil, acid and alkali corrosion, and can maintain the correct geometry. The porosity is large, the grinding rate is high, the strength is large, the toughness, elasticity, the vibration resistance is poor, can not withstand the side force, the grinding of the V wheel < 35m/s, the grinding machine grinding editor tells you: this binder is the most widely used, can be made into a variety of grinding tools, suitable for forming grinding and grinding threads, gears, crankshaft and so on." Editor-in-chief Mill Wang tells you that many ceramic binders are now applied to higher speeds, 50-80m/s, and many are used in examples.
The existing resin bond is strong and elastic, not afraid of impact, and can work at high speed. It has the effect of friction polishing, but its firmness and heat resistance are poor compared with ceramic binder, it is not resistant to acid and alkali, and its porosity is small and easy to block. V wheel > 50m/s high speed grinding, can be made into a wafer grinding wheel groove grinding tool front cutter face, high precision grinding.
Inorganic polymer binder grinding tool has high strength, so it has a high speed of use, generally suitable for high-speed cutting, rough grinding, heavy load grinding; In addition, the inorganic polymer binder grinding has certain elasticity, high heat resistance of the binder and good grinding self-sharpness, so that compared with the traditional resin binder, the sharp Angle of the grinding wheel is good, the shape retention is good, and it is also suitable for fine grinding, such as thread grinding, forming grinding and sharpening. It can be said that the inorganic polymer binder has both the performance of ceramic abrasives and the performance of resin abrasives, and at the same time avoids their defects.
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The production of inorganic polymer binder abrasives is based on the theoretical basis of grinding and application research, and the concept of composite materials is introduced into the production of abrasive tools, and the basic principles of physical chemistry of inorganic polymer binder (1. The crystal chemistry of inorganic polymer materials 2. Thermodynamics of inorganic polymer materials 3. Process dynamics of inorganic polymer materials) and the interface of composite materials and the strengthening and toughening mechanism are introduced, specifically talking about the application of inorganic polymer bonds in the production of new, high efficiency, special, heavy load strength and precision abrasives. Although this advanced process technology has gradually been mastered by some tool industries, there are still some specific problems that need to be seriously summarized and solved.
The following is the specific design principles and methods of inorganic polymer bonding abrasives, the production of inorganic polymer composite abrasives high speed heavy load, rough grinding abrasives, strong grinding abrasives, high efficiency deep grinding, slow feed grinding abrasives, fast point grinding abrasives, high efficiency grinding abrasives, spindle and bearing abrasives, high efficiency grinding abrasives, rail grinding abrasives, sand belt grinding processes Methods To give some superficial views.
Design principle and method of inorganic polymer binder abrasive tool
The following issues should be considered in the design and manufacture of grinding wheels:
First of all, the properties of the processed material and the accuracy of the material processing surface should be considered, and then the appropriate abrasive, particle size and grinding use of mixed abrasives should be selected.
The second is the grinding wheel working conditions of various forces, impact resistance, speed, temperature, processing material and grinding wheel service life and the selection of the appropriate bond, auxiliary materials, and consider the matching between each other and scientific process. Grinding machine grinding micro signal
"Grinding king" tells you: the strength of the grinding tool depends on the performance of the bond, the manufacturing process of the grinding tool and the specifications of the grinding tool. Factors affecting abrasive strength include: abrasive type, particle size, binder type and performance, abrasive hardness, structure, density, mixing, molding process and curing process conditions, abrasive shape, the ratio of abrasive wheel diameter to aperture and so on. Among them, after the characteristics and specifications of abrasive tools are given, the performance of the binder, the mixing molding process and the curing process conditions are the most important.
In addition, the grinding ratio of the grinding wheel is also an important parameter. For the above involved factors, let's talk about one by one:
Abrasives and abrasive thickness and particle gradation in the combination of abrasives matrix
The thickness of abrasives - refers to the overall thickness of abrasives of different particle sizes mixed together; Particle grading refers to the combination or collocation of abrasives of different kinds, sizes and quantities.
Abrasive is an important factor in grinding, abrasive selection is mainly based on the properties of the workpiece material, such as hardness, tensile strength, toughness and so on to determine.
The basic principles for selecting abrasives are:
When grinding workpiece materials with high hardness, abrasives with higher hardness should be selected;
When grinding workpiece materials with high tensile strength, abrasives with high toughness should be selected;
When grinding materials with low tensile strength, silicon carbide abrasives with higher brittleness or strength should be selected.
The performance, use and selection of various abrasives are not discussed in detail here.
When choosing abrasive particle size, "grinding machine grinding wechat editor" grinding Wang "tells you that the main choice should be based on the requirements of processing accuracy, surface roughness and grinding efficiency.
"Mill King" : The general principles are as follows
The grinding parts are required to have high roughness, and coarse grain size should be selected;
The surface roughness is required to be low, and fine particle size should be selected.
When the workpiece requires higher geometric accuracy and lower surface roughness, the mixed particle size should be selected.
The workpiece geometric accuracy requirements are high, when the abrasive wheel and the workpiece contact area is small, should choose fine granularity; When the contact area is large, choose coarse grain size. The workpiece material is hard and brittle, and fine granularity should be selected;
The workpiece material is soft and tough, and coarse grain size should be selected.
The thermal conductivity of the workpiece is poor, easy to heat deformation, easy to burn, should choose coarser particle size.
These problems also involve the thermal conductivity, heat capacity, density, porosity and other factors that affect grinding.
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Abrasives are usually divided into coarse abrasives, medium abrasives, fine abrasives and micro-powder abrasives.
Under the same abrasive condition, the total surface area of the micro-powder abrasive is larger, and the total surface area of the coarse abrasive is smaller. In the production of abrasives, the surface needs to be wrapped with a nodule agent to give bonding strength, and the greater the total surface area of the abrasive, the more inorganic polymer bonding agents need to be wrapped on the abrasive surface. Generally, the binding dose of inorganic polymers used in coarse abrasives is less than that used in fine abrasives.
Abrasive particle grading, in order to improve the grinding efficiency, not only to consider the strength of the abrasive and processing materials, but also must determine the amount of several abrasives, abrasive grinding machine grinding general editor called the grading of abrasive.
When grinding, the grinding tool is affected by the impact of the grinding body on the one hand, and the damage of the grinding body on the other hand, so as to ensure the sharpness of the grinding tool and complete the entire grinding process.
Obviously, in the unit time, the more contact points of the grinding body involved in grinding, that is, the more abrasive particles involved in grinding per unit time, the higher the grinding efficiency.
When the abrasive is fixed, the contact between the abrasive and the grinding body should be increased, and the smaller the size of the abrasive, the better.
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But on the other hand, in order to complete the grinding of the grinding workpiece, the grinding tool must have sufficient impact capacity.
The task of the grinding tool "grinding king" tells you that it is necessary to ensure sufficient ability to grind the material of the workpiece, and to ensure that the grinding tool grinds the workpiece to a certain fineness, therefore, in the case of certain other conditions (such as the strength of the grinding tool, the speed of the grinding tool, etc.), this task can only be completed by choosing the suitable size of the abrasive and the reasonable proportion of them.
The gap between abrasives in the production of abrasives is theoretically generated after the binder is coated with abrasives. In order to achieve the purpose of using less inorganic polymer binder to meet the strength of abrasives and to improve the grinding efficiency, the gap between abrasives should be minimized.
Another used concept that should be clarified is that people are accustomed to the workpiece grinding burns attributed to the abrasive wheel group value is too dense, lack of sufficient chip porosity.
During grinding, the porosity plays the role of chip storage and chip removal, and can contain the coolant, which is conducive to the dissipation of grinding heat. In order to meet some special processing requirements, the pores of traditional abrasives can also be impregnated with certain fillers, such as sulfur and paraffin, to improve the performance of abrasives. This filler is also traditionally known as the fourth element of abrasives. This is not always true, because the number of chips produced in high-cut grinding is too large to be accommodated by small pores, and the superhard abrasive wheel has no pores at all. As long as the surface is properly sharpened, it can work well. If the pore volume ratio of the resin abrasive wheel is increased, it will inevitably reduce its strength and make it wear prematurely, which is not worth the loss.
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In addition, the influence of the grinding wheel working line speed on the number of grinding chips is more complex, when the grinding wheel is increased from 28.8m/s to 33.6m/s, the speed is increased by 16%, and the amount of blockage is increased by three times. Because the increase of the line speed of the grinding wheel reduces the maximum cutting depth of the abrasive particle, the cross-sectional area of the chip decreases, and the cutting times and grinding heat increase, both of these factors increase the amount of plugging, but when the line speed of the grinding wheel is up to a certain degree (such as up to 50m/s or more) the amount of plugging of the grinding wheel is greatly reduced. For each workpiece material, there is a certain critical grinding wheel speed value with minimum plugging amount. The production of inorganic polymer bonding abrasives has little consideration for these, and the grinding theory about these will be introduced again in the future special. If you want to see more about the analysis in the future, please stay tuned. If it feels valuable, the positive energy transmitted by the editor-in-chief "Mill King" is transmitted by relay. Put in the circle of friends, professional level bar beep!
