|Title||Grinding wheel blockage problem|
|Description||The types of grinding wheel blockage are embedded type, dependent type, adhesive tape, and mixed type. The embedded type plugging is a blocked state in which the grinding debris is embedded in the air hole of the working surface of the grinding wheel. Dependent plugging is a clogging condition in which the abrasive particles are attached to the flank of the China cutting disc for metal by temporary force. Adhesive plugging refers to adhesion to the periphery of the abrasive cutting edge or the adhesive after the grinding is melted. A hybrid plug is a collection or set of layers of the above three types at a certain location. Adhesive blockage mechanism Mechanism of embedded and dependent plugging The embedded type and the attached type of plugging are clogging phenomena in which the abrasive chips are mechanically filled in the gap of the grinding wheel. The power of filling comes from two aspects, one is external and the other is internal, involving physical, electrical, thermal and other factors. External factors: There is a very important feature in grinding. The radial grinding component Fy is larger than the tangential component Fz, Fy/Fz ≥ 2~10. The harder the workpiece material is, the smaller the plasticity is. The larger the Fy/Fz ratio is. Thus, the grinding debris of the grinding zone is mechanically squeezed into the gap of the surface of the grinding wheel under the action of strong positive pressure. From the microscopic analysis, the grinding debris slides out along the front of the abrasive grain, and a few layers of wear debris accumulate in the local area in front of the abrasive grain. After the abrasive grain, due to the high-speed rotation of the grinding wheel, a vortex zone is formed, and the vortex zone is formed. The air pressure is significantly reduced. Under the action of negative pressure, part of the abrasive debris is attached to the back of the abrasive grain to form a dependency clogging of the abrasive flank, and most of the attachments are ash and particles. The role of the electrostatic field: the relative speed of the grinding wheel and the workpiece is V and much larger than V work, V seconds of ordinary grinding machine = 3 ~ 50m / s, the mature value of the grinding speed of high-speed grinding machine in China is 50 ~ 80 / s, foreign test The speed is from 200m/s to 250m/s, and the speed of the workpiece is below 1.5m/s. When the grinding wheel and the work are moving relative to each other, in the grinding zone, the grinding wheel and the surface of the workpiece will be charged according to a certain regularity due to the escape of electrons. At the same time, the gas in the grinding zone will also be excited to discharge due to the high temperature, so that the neutral gas is ionized into positive ions and electrons. In some small areas of the grinding zone, a small electric field consisting of a grinding wheel and a workpiece is formed. In the electric field, there are neutral atoms, positive ions, electrons, impurities, dust, not only the process of neutralization of neutral atoms but also positive The process of complexing ions with electrons. Under the action of the electric field, part of the grinding debris will exhibit polarity. According to the principle of opposite attraction, the grinding debris with the opposite polarity of the grinding wheel is adsorbed on the working surface of the grinding wheel. Since the electric field strength is small, the adsorption force is also weak, and the grinding debris is not reliable on the surface of the grinding wheel. However, with the large mechanical pressure between the grinding wheel and the workpiece, the grinding debris that has been adsorbed on the surface of the grinding wheel can be stably embedded in the grinding wheel. Between the gaps on the surface.|
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