Installation balance and dressing of the hottest g

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Installation, balance and dressing of grinding wheel

1 Installation of grinding wheel

special attention should be paid to the installation of grinding wheel on grinding machine. Because the grinding wheel works under the condition of high-speed rotation, it should be carefully checked before use, and cracks are not allowed. The installation must be firm and adjusted by static balance to avoid personal injury and quality accidents

the inner hole of the grinding wheel and the outer circle of the grinding wheel shaft or flange plate should not be too tight, otherwise it will be heated and expanded during grinding, so as to remove the damage layer generated during grinding as soon as possible. It is easy not to disassemble the machine to expand and crack the grinding wheel, nor should it be too loose, otherwise the grinding wheel is easy to be eccentric, lose balance, and cause vibration. Generally, the fitting clearance is 0.1~0.8mm, and the clearance of high-speed grinding wheel should be smaller. When clamping the grinding wheel with a flange, the diameters of the two flanges should be equal, and their outer diameter should not be less than 1/3 of the outer diameter of the grinding wheel. Thick cardboard or oil resistant rubber shall be used as a gasket between the flange and the end face of the grinding wheel to make the pressure evenly distributed. The tightening force of the nut shall not be too large, otherwise the grinding wheel will crack. Note that the rotation direction of the fastening thread should be opposite to that of the grinding wheel, that is, when the grinding wheel slowly unloads the load and the needle rotates counterclockwise, use the right-hand thread, so that the grinding wheel will drive the nut to tighten more and more under the action of grinding force

2. Balance of grinding wheel

generally, the grinding wheel with a diameter greater than 125mm should be balanced so that the center of gravity of the grinding wheel coincides with its rotation axis

when the unbalanced grinding wheel rotates at high speed, it will produce vibration, make a color noise on the machining quality and the accuracy of the machine tool, and even cause machine damage and grinding wheel fragmentation in serious cases The main causes of unbalance are uneven density, asymmetric geometry and eccentric installation of each part of the grinding wheel. Therefore, the grinding wheel must be balanced before installation. The balance of the grinding wheel includes static balance and dynamic balance. In one case, only static balance is needed, but in high-speed mushroom cutting (speed greater than 50m/s) and high-profile grinding, dynamic balance must be carried out The figure below shows the static balancing device of grinding wheel When balancing, install the grinding wheel on the balance spindle then place the grinding wheel with the spindle flat on the balance guide rail of the balance frame, and the grinding wheel will swing back and forth until the swing stops. The balanced grinding wheel can stand still at any position. If the grinding wheel is unbalanced, the heavier part will always turn down At this time, the position of the balance weight can be moved to achieve balance. The balanced grinding wheel must be checked for cracks before being installed on the spindle of the machine tool. The grinding wheel with cracks must not be used During installation, a 0 5-1 volume elastic backing plate: the diameters of the two flanges must be equal, and its size is generally half of the diameter of the grinding wheel There should be a certain gap between the grinding wheel and the grinding wheel shaft or the step flange to avoid the expansion of the main shaft by heating and cracking the grinding wheel

figure balance of grinding wheel

1-grinding wheel 2-spindle 3-flange 4-balancing block 5-balancing track 6-balancing frame

method of balancing grinding wheel: install several balancing blocks in the annular groove of grinding wheel flange, and make the center of gravity of grinding wheel coincide with its rotation axis by adjusting the position of balancing block

3. Dressing of grinding wheel

in the grinding process, the edges and corners of the grinding wheel are gradually rounded and blunt under the action of friction and extrusion, or when grinding ductile materials, the grinding debris is often embedded in the pores of the grinding wheel surface, blocking the grinding wheel surface, and finally making the grinding wheel lose cutting ability. At this time, there will be slippage between the grinding wheel and the workpiece, which may cause vibration and noise, reduce the grinding efficiency and deteriorate the surface roughness. At the same time, due to the increase of grinding force and grinding heat, it will cause workpiece deformation and affect the grinding accuracy. In serious cases, it will also cause burns and small cracks on the grinding surface. In addition, due to the uneven hardness of the grinding wheel and the different working conditions of the abrasive particles, the wear of the working surface of the grinding wheel is uneven, and the number of abrasive particles falling off at each part is different, resulting in the loss of shape accuracy of the grinding wheel and affecting the shape accuracy and roughness of the workpiece surface. In case of the above situation, the grinding wheel must be trimmed, and a layer of abrasive on the surface must be cut off to expose the smooth and sharp abrasive particles on the surface of the grinding wheel again, so as to restore the cutting ability and shape accuracy of the grinding wheel

the second grinding wheel is usually trimmed with diamond, which has high hardness and wear resistance, and is the main tool for dressing the grinding wheel. (end)

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